CN105209375A

CN105209375A - Integrated power generation and carbon capture using fuel cells

Info

Publication number: CN105209375A
Application number: CN201480027118.1A
Authority: CN
Inventors: P·J·贝洛维茨; T·A·巴尔克霍尔兹; F·赫什科维茨
Original assignee: ExxonMobil Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 2013-03-15
Filing date: 2014-03-13
Publication date: 2015-12-30
Also published as: AU2014235197B2; AU2014235198B2; KR20150131068A; AU2014235197A1; CA2902862A1; CA2902860C; AU2014235212A1; AU2014235193A1; CA2902860A1; AU2014235203A1; AU2014235219B2; CA2902861A1; AU2014235219A1; AU2014235198A1; CA2902862C; AU2014235275A1; AU2014235193B2; AU2014235203B2

Abstract

Systems and methods are provided for capturing CO2 from a combustion source using molten carbonate fuel cells (MCFCs). At least a portion of the anode exhaust can be recycled for use as a fuel for the combustion source. Optionally, a second portion of the anode exhaust can be recycled for use as part of an anode input stream. This can allow for a reduction in the amount of fuel cell area required for separating CO2 from the combustion source exhaust and/or modifications in how the fuel cells can be operated.

Description

Use comprehensive electric generating and the carbon trapping of fuel cell

Invention field

In in various, the present invention relates to the low emission power generation of the discharge produced with integrated purification and/or the trapping of the burning energy by molten carbonate fuel cell.

Background of invention

The trapping of the gas of power station discharge is more and more concerned field.Power station based on the burning of fossil oil (such as oil, Sweet natural gas or coal) generates carbonic acid gas as byproduct of reaction.In history, after combustion by this release of carbonate dioxide in air.But, more and more wish that the carbonic acid gas pointing out as generating in combustion processes finds the mode of alternative purposes.

The option managing the carbonic acid gas generated by combustion reactions uses method of trapping by CO ₂with other gas delivery in burning and gas-exhausting.Make this exhaust stream through amine washer for trapping an example of the traditional method of carbon.Although amine washer can effective separation of C O from exhaust stream ₂, but have several shortcoming.Especially, energy is needed to run the temperature and pressure of amine washer and/or change exhaust stream to be applicable to through amine washer.CO ₂energy needed for separation reduces the overall efficiency of electrification technique as well as.

In order to compensate CO ₂power needed for trapping, an option uses molten carbonate fuel cell to assist CO ₂be separated.Cause CO ₂the fuel cell reaction being transferred to the anode part of fuel cell from the cathode portion of fuel cell also can cause electric power to generate.But the conventional combination of the fuel cell that burning energy supply turbine or generator are separated with for carbon causes the generating efficiency of per unit consume fuel only to reduce.

One section of article (people such as G.Manzolini in JournalofFuelCellScienceandTechnology, J.FuelCellSci.andTech., 9th volume, in February, 2012) describe a kind of power generation system burning generators and molten carbonate fuel cell combined.Describe various layout and the operating parameter of fuel cell.From burning generators burning output be used as the input of fuel battery negative pole.Export through deep cooling CO making anode ₂this input is supplemented with the recycling part that this anode exports after separator.

A target of the simulation in Manzolini article uses MCFC separation of C O from the waste gas of generator ₂.The simulation described in Manzolini article establishes the maximum temperature out of 660 DEG C and points out that temperature in is sufficiently colder with the intensification taken into account through fuel cell.In basic model truth shape, the electrical efficiency (i.e. generated energy/fuel input) of MCFC fuel cell is 50%.For CO ₂the electrical efficiency caught in the trial model situation optimized also is 50%.

The article (Intl.J.ofHydrogenEnergy, Vol.37,2012) of the people such as Desideri describes and uses fuel cell separation of C O ₂the modeling method of performance of power generation system.Anode off-gas recirculation is utilized to be recycled to cathode inlet to improve the performance of fuel cell to anode inlet and cathode exhaust gas.Based on the model shown in this article and configuration, demonstrate, improve the CO in fuel cell ₂utilization ratio is applicable to improve CO ₂separation.Model parameter describes the MCFC electrical efficiency of 50.3%.

U.S. Patent No. 7,396,603 describe minimizing CO ₂the integrated fossil-fuelled power-plants of discharge and fuel cell system.Anode exports and remove a part of CO in exporting from this anode at least partially ₂after be recycled to anode input.

Molten carbonate fuel cell utilizes hydrogen and/or other fuel power generation function.Hydrogen is provided by reforming methane in the steam reformer in fuel cell upstream or fuel cell or other reformable fuel.Reformable fuel can comprise and can react the hydrocarbon material of the gaseous product producing hydrogen with steam and/or oxygen at elevated temperatures and/or pressures.Especially, reformable fuel can include but not limited to alkane, alkene, alcohol, aromatic substance and/or reformable generation H ₂with oxycarbide (CO or CO ₂) other carbonaceous and organic compound.Or or in addition, fuel can be reformed in the anode pool of molten carbonate fuel cell, described fuel cell can be run to create the condition being applicable to fuel reforming in the anode.Or or in addition, can reform in the outside of fuel cell and inside.

Traditionally, run the Energy Maximization that molten carbonate fuel cell inputs to make per unit fuel, this can be referred to as the electrical efficiency of fuel cell.This maximization can based on alone or the fuel cell be combined with another power generation system.In order to the generated energy realizing improving generates heat with management, the fuel availability in fuel cell remains on 70% to 75% usually.

US publication application 2011/0111315 describes a kind of system and method that there is the fuel cell operation system of remarkable hydrogen content in anode inlet stream.Technology during ' 315 are open relate to anode inlet provide enough fuel with at fuel close to still having enough fuel for oxidizing reaction during anode export.In order to ensure enough fuel, ' 315 openly provide has high H ₂the fuel of concentration.The H do not used in oxidizing reaction ₂be recycled to anode for next journey.By one way, H ₂utilization ratio can be 10% to 30%.Document ' 315 do not describe the remarkable reformation in anode, but reform in the main outside that relies on.

US publication application 2005/0123810 describes a kind of system and method for hydrogen and electric energy coproduction.This co-generation system comprises fuel cell and is configured to receive anode exhaust stream and the separating unit of separating hydrogen gas.Part anode exhaust is also recycled to anode inlet.The operating range provided during ' 810 are open seems based on Solid Oxide Fuel Cell.Molten carbonate fuel cell is described to surrogate.

US publication application 2003/0008183 describes a kind of system and method for hydrogen and electric power co.As for becoming the universal class of the chemical converter of hydrogen to mention fuel cell hydrocarbon type converting fuel.This fuel cell system also comprises external reformer and high-temperature fuel cell.Describe an embodiment of this fuel cell system, it has the electrical efficiency of about 45% and the chemical production rate of about 25%, causes system coproduction efficiency to be about 70%.' 183 openly seem do not have to describe the electrical efficiency independent of the fuel cell of this system.

United States Patent (USP) 5,084,362 describe a kind of using fuel cell and gasification system integrated coal gas can be used as the system of the fuel source of anode of fuel cell.The hydrogen using fuel cell to generate is as the charging of the gasifier for being generated methane by coal gas (or other coal) charging.Then use methane from gasifier as the fuel of input at least partially of fuel cell.Thus, the form indirect recycling of the methane that the hydrogen at least partially that fuel cell generates generates with gasifier is to fuel cell anode inlet.

Summary of the invention

In one aspect of the invention, provide the method for a kind of trapping from the carbonic acid gas of Combustion Source.The method can comprise: by one or more fuel streams with containing O ₂combustion zone introduced by stream; Carry out combustion reactions in combustion zone, produce burning and gas-exhausting, burning and gas-exhausting comprises CO ₂; Use at least first part of the fuel cell array processing burning and gas-exhausting of one or more molten carbonate fuel cell, cathode exhaust gas stream is formed by least one cathode outlet of fuel cell array, described one or more fuel cell has anode and negative electrode separately, and described molten carbonate fuel cell and burning and gas-exhausting are operated by one or more cathode inlets of fuel cell in fuel cell array and be connected; Make to react at described one or more anode of fuel cell from the carbonate of described one or more fuel battery negative pole and hydrogen to produce electricity, the anode exhaust stream from least one anode export of fuel cell array comprises CO ₂and H ₂; By anode exhaust stream separation of C O in one or more segregation section ₂, form poor CO ₂anode exhaust stream; With by described poor CO ₂anode exhaust stream at least first part send into combustion zone.Optionally, the method also can comprise described poor CO ₂at least second section of anode exhaust stream be recycled to anode.

In another aspect of this invention, provide the system for generating electricity.This system can comprise: the combustion turbine comprising compressor, described compressor receives oxygenant input and is communicated with combustion zone fluid, described combustion zone receives the first fuel input further and the second fuel inputs, and described combustion zone is vented the decompressor fluid exported and is communicated with having; Exhaust gas recycling system, which provides the first part exported at described expander exhaust gas and is communicated with the fluid between combustion zone; Fuel cell array, it has the input of at least one negative electrode, at least one negative electrode exports, at least one anode inputs and at least one anode exports, and the second section that described expander exhaust gas exports is communicated with at least one negative electrode input fluid described; Comprise the anode recirculation loop of one or more carbon dioxide separation section, the first part that anode recirculation loop exports is supplied to combustion zone as described second fuel input at least partially.Optionally, the second section that described anode recirculation loop exports is supplied to anode input.

The application is relevant with the PCT application of other 21 common pending trials, and they therewith to be submitted to and by following attorney docket and name identification in same date: the 2013EM104-WO that name is called " IntegratedPowerGenerationandCarbonCaptureusingFuelCells "; Name is called the 2013EM107-WO of " IntegratedPowerGenerationandCarbonCaptureusingFuelCells "; Name is called the 2013EM109-WO of " IntegratedPowerGenerationandCarbonCaptureusingFuelCells "; Name is called the 2013EM272-WO of " IntegratedPowerGenerationandChemicalProductionusingFuelC ells "; Name is called the 2013EM273-WO of " IntegratedPowerGenerationandChemicalProductionusingFuelC ellsataReducedElectricalEfficiency "; Name is called the 2013EM274-WO of " IntegratedPowerGenerationandChemicalProductionusingFuelC ells "; Name is called the 2013EM277-WO of " IntegratedPowerGenerationandChemicalProductionusingFuelC ells "; Name is called the 2013EM278-WO of " IntegratedCarbonCaptureandChemicalProductionusingFuelCel ls "; Name is called the 2013EM279-WO of " IntegratedPowerGenerationandChemicalProductionusingFuelC ells "; Name is called the 2013EM285-WO of " IntegratedOperationofMoltenCarbonateFuelCells "; Name is called the 2014EM047-WO of " MitigationofNOxinIntegratedPowerProduction "; Name is called the 2014EM048-WO of " IntegratedPowerGenerationusingMoltenCarbonateFuelCells "; Name is called the 2014EM049-WO of " IntegratedofMoltenCarbonateFuelCellsinFischer-TropschSyn thesis "; Name is called the 2014EM050-WO of " IntegratedofMoltenCarbonateFuelCellsinFischer-TropschSyn thesis "; Name is called the 2014EM051-WO of " IntegratedofMoltenCarbonateFuelCellsinFischer-TropschSyn thesis "; Name is called the 2014EM052-WO of " IntegratedofMoltenCarbonateFuelCellsinMethanolSynthesis "; Name is called the 2014EM053-WO of " IntegratedofMoltenCarbonateFuelCellsinaRefinerySetting "; Name is called the 2014EM054-WO of " IntegratedofMoltenCarbonateFuelCellsforSynthesisofNitrog enCompounds "; Name is called the 2014EM055-WO of " IntegratedofMoltenCarbonateFuelCellswithFermentationProc esses "; Name is called the 2014EM056-WO of " IntegratedofMoltenCarbonateFuelCellsinIronandSteelProces sing "; The 2014EM057-WO of " IntegratedofMoltenCarbonateFuelCellsinCementProcessing " is called with name.Each in the PCT application of these common pending trials is incorporated to herein through quoting in full.

Accompanying drawing is sketched

Fig. 1 schematically shows an example of the combined cycle system of the generating based on carbon-based fuel burning.

Fig. 2 schematically shows an example of the operation of molten carbonate fuel cell.

Fig. 3 shows an example of the relation between the anode fuel utilization ratio of molten carbonate fuel cell and voltage.

Fig. 4 schematically shows an example of the configuration of anode recirculation loop.

Fig. 5 shows the CO of molten carbonate fuel cell ₂an example of utilization ratio, relation between voltage and power.

Fig. 6 schematically shows an example of the configuration of molten carbonate fuel cell and relevant reformation and segregation section.

Fig. 7 schematically shows another example of the configuration of molten carbonate fuel cell and relevant reformation and segregation section.

Fig. 8 schematically shows an example of the combined cycle system of the generating based on carbon-based fuel burning.

Fig. 9 schematically shows an example of the combined cycle system of the generating based on carbon-based fuel burning.

Figure 10-14 shows the result from comprising burning energy supply turbine and the simulation for separating of the various configurations of the power generation system of the molten carbonate fuel cell of carbonic acid gas.

Figure 15 and 16 is presented at different fuel battery operating voltage V _aunder CH ₄the example of transformation efficiency.

Embodiment describes in detail

In all fields, provide the CO using molten carbonate fuel cell (MCFCs) trapping from Combustion Source ₂system and method.This system and method can solve and trap and/or use molten carbonate fuel cell to carry out carbon with the carbon from burning and gas-exhausting stream to trap relevant one or more problems.

Use molten carbonate fuel cell separation of C O from exhaust stream ₂a difficulty can comprise the big area of the fuel cell that process needs usually from the exhaust of commercial size turbine or other electricity/heat(ing)generator.Use molten carbonate fuel cell to receive commercial size evacuation circuit and usually can relate to the multiple fuel cell of use but not the single fuel cell that there is enough areas.In order to the plurality of fuel cell conveying exhaust stream, the connection added can be needed with segmentation exhaust between each fuel cell.Therefore, the fuel cell area needed for carbonic acid gas reducing trapping aequum can provide the corresponding reduction of required flow process linking number and/or complicacy.

In some aspects of the invention, maybe processing is contained CO by making anode exhaust stream recirculation at least partially get back to anode inlet to reduce ₂the fuel cell area needed for exhaust stream minimize.In addition or or, can at fuel cell operation under comparatively low fuel utilization ratio.Exhaust stream can be sent into the negative electrode of molten carbonate fuel cell.In the operational process of this fuel cell, anode exhaust can be passed through one or more segregation section.This can comprise for removing H ₂o and/or CO ₂segregation section.Then can by residue anode exhaust be recycled to anode inlet at least partially.In a preferred embodiment, anode exhaust can be avoided directly to any recirculation of negative electrode.By will anode off-gas recirculation is to anode inlet at least partially, at least some of the fuel do not utilized in by the first journey of anode can be utilized in stroke subsequently.

Except by except anode off-gas recirculation to anode inlet or as an alternative, the hydrogen at least partially in anode exhaust can be recycled to the combustion zone of turbine or the generator/thermal source of other burning energy supply.It is to be noted, any hydrogen produced by the reformation of the part as plate tank can represent wherein CO ₂by being transferred to plate tank by the fuel of " trapping ".This can reduce and will be transferred to CO needed for anode side from the cathode side of fuel cell ₂amount, therefore can cause reduce fuel cell area.

Contributive extra or alternative characteristics can be able to be reduce and/or minimize the amount of the energy needed for technique be not directly included in generating to the fuel cell area reduced.Anodic reaction such as in molten carbonate fuel cell can make H ₂and the electrolytical CO be conveyed through between negative electrode and anode ₃ ^2-in conjunction with, form H ₂o and CO ₂.Although anodic reaction environment to a certain degree can promote that fuel is as CH ₄reform and form H ₂, but can advantageously there are some H in fuel ₂to keep desirable speed of reaction at anode.Therefore, before entering anode itself, fuel (as natural gas/methane) was conventionally reformed at least in part before entering anode.Reforming sections before the anode of fuel cell can need extra heat to integrate suitable temperature to keep counterweight.

In some aspects of the invention, anode off-gas recirculation is at least partially enable to reduce reformation amount to anode inlet and/or eliminate the reforming sections before anode inlet.Replace fuel reforming stream before entering anode, the anode exhaust of recirculation can provide enough hydrogen for the fuel input of anode.This can allow anode to input stream and just send into anode without independent pre-reforming section.Under the hydrogen fuel utilization ratio level reduced, run anode be conducive to further by providing the anode exhaust of the hydrogen content with raising reducing and/or eliminating pre-reforming section.In anode inlet charging, still there is enough hydrogen thus while can reducing and/or eliminating pre-reforming, increase hydrogen content and a part for anode exhaust can be allowed also to be used as the input in turbine combustion district.

Another challenge during molten carbonate fuel cell is used to be attributable to the relatively low CO of the exhaust of the internal combustion turbine suitably run ₂content.Such as, by low CO ₂the internal combustion turbine of the natural gas fuel source energy supply of content can generate the CO such as containing about 4 volume % ₂exhaust.If use the exhaust gas recirculatioon of certain type, this value can bring up to such as about 6 volume %.Unlike this, molten carbonate fuel cell negative electrode input typical case needed for CO ₂content can be about 10% or larger.In some aspects of the invention, provide in this article and still effectively can improve the CO in exhaust while operating gas turbine or other burning energy supply generator ₂the system and method for content.In some aspects of the invention, provide with having low CO ₂the system and method for the carbon collection efficiency of improvement and/or optimization fuel cell when the cathode exhaust gas of content is run.

Another challenge can comprise reduce or alleviate by carbon trap cause generating efficiency loss.As mentioned above, traditional carbon capture method can cause the loss of the generating net efficiency of per unit consume fuel.In some aspects of the invention, the system and method improving total generating efficiency is provided.In addition or or, in some aspects of the invention, provide to reduce and/or will the CO having commercial value be generated ₂the mode separation of C O that energy needed for stream minimizes ₂method.

Of the present invention most of in, can at least partly by with association circulating power generation system, combined-cycle power plant as gas-firing is combined molten carbonate fuel cell and realizes one or more above-mentioned advantage, wherein also can be used for steam turbine energy supply from the stack gas of combustion reactions and/or heat.More generally, this molten carbonate fuel cell can with various types of electricity or hot generation systems, as the generator combined use of burning energy supply of boiler, burner, catalytic oxidizer and/or other type.In some aspects of the invention, from the anode exhaust at least partially of MCFCs (at separation of C O ₂can be recycled to afterwards) in the inlet flow of MCFC anode.In addition or or, can by a part of anode off-gas recirculation from MCFCs to the inlet flow of the combustion reactions being used for generating electricity.MCFCs can residue (unreacted) H in anode exhaust wherein ₂in the aspect run, by a part of H from anode exhaust ₂be recycled to anode input and can reduce the fuel run needed for MCFCs.Be delivered to the H of combustion reactions ₂part can advantageously change and/or improve the reaction conditions of combustion reactions, causes more effective generating.Water gas shift reaction district after anode exhaust can optionally for improving the H existed in anode exhaust further ₂amount, also can change into more segregative CO by CO simultaneously ₂.

Of the present invention various in, can provide and use molten carbonate fuel cell trapping from the CO of Combustion Source ₂the method of improvement.This can comprise the system and method such as using turbine (or based on other electricity or hot method for generation of burning, as boiler, burner and/or catalytic oxidizer) to generate electricity while the discharge reduced and/or alleviate in power generation process.This optionally at least partly by using association circulating power generation system to realize, wherein also can be used for steam turbine energy supply from the stack gas of combustion reactions and/or heat.In addition or or, this can at least partly by using one or more molten carbonate fuel cell (MCFCs) to realize as carbon capturing device and auxiliary power source.In some aspects of the invention, this MCFCs can run under low fuel utilization ratio condition, and this can improve the carbon trapping in fuel cell, also reduces simultaneously and/or is minimized by the fuel quantity of loss or waste.In addition or or, can run this MCFCs with reduce and/or reduce the CO of combustion flue gas stream to greatest extent ₂content is down to desired level, the MCFCs sum that such as 1.5 volume % or lower or 1.0 volume % or lower are required and/or volume.In in such, (usually at least arranged in series is comprised for from array sequence, or last (multiple) negative electrode is identical with initial (multiple) negative electrode) in the negative electrode of last (multiple) negative electrode export, export to form and can comprise about 2.0 volume % or less CO ₂the CO of (such as, the less or about 1.2 volume % of about 1.5 volume % or less) and/or at least about 1.0 volume % ₂, as at least about 1.2 volume % or at least about 1.5 volume %.Can at least partly by anode off-gas recirculation being returned anode inlet and removed the CO at least partially in anode exhaust before sending anode exhaust back to anode inlet ₂realize these aspects.Can such as use deep cooling CO ₂separator realizes so removing CO from anode exhaust ₂.More of the present invention optional in, can by anode off-gas recirculation to anode inlet so that do not provide path anode exhaust being directly recycled to cathode inlet.By avoiding anode exhaust to be directly recycled to cathode inlet, be transferred to any CO of anode recirculation loop through MCFCs ₂can stay in anode recirculation loop until isolate CO from other gas this loop ₂.

Molten carbonate fuel cell makes traditionally in a standalone mode for generating.In stand-alone mode, can by fuel, the anode side of molten carbonate fuel cell sent into by the input stream as methane.(outside or inside) methane can be reformed to form H ₂with other gas.H ₂then can react form CO through electrolytical carbanion in a fuel cell with from negative electrode ₂and H ₂o.For the reaction in anode of fuel cell, fuel availability is typically about 70% or 75% or even higher.In conventional arrangement, consider the endothermic nature of reforming reaction, can by residual fuel oxidation (burning) in anode exhaust to generate the heat of the temperature for keeping fuel cell and/or external reformer.Air and/or another oxygen source can be added so that more perfect combustion in this oxidising process.Then anode exhaust (after oxidation) can be sent into negative electrode.Thus, the single-fuel stream entering anode can be used for for anode and negative electrode provide all energy and nearly all reactant.This configuration also can make to enter all of anode and run out of gas, and only needs ~ 70% or ~ 75% or slightly high fuel availability in the anode simultaneously.

In the typical above-mentioned independent solution of legacy system possibility, the target running molten carbonate fuel cell normally effectively may generate electric power based on input fuel streams.Unlike this, the molten carbonate fuel cell integrated from the energy supply turbine that burns, engine or other generator can be used to provide different utilizations.Although the generating of fuel cell is still desirable, can fuel cell operation such as to improve for the fuel cell of given volume and/or to maximize the CO that trapped by exhaust stream ₂amount.This can improve CO while still by fuel cell power generation ₂trapping.In addition, in some aspects of the invention, the exhaust from the anode of fuel cell still can contain excess hydrogen.This excess hydrogen can be advantageously used for the fuel of turbine combustion reaction, thus allows the turbine efficiency of improvement.

Fig. 1 provides the schematic overview of the concept of aspects more of the present invention.Thering is provided Fig. 1 to help understanding universal, therefore can be incorporated to additional charging, technique and/or configuration in FIG and not deviating from the spirit of global concept.In the general view example shown in Fig. 1, natural gas turbines 110 (or another burning energy supply turbine) can be used to generate electric power based on the burning of fuel 112.For the natural gas turbines 110 shown in Fig. 1, this can comprise compressed air stream or other gas phase stream 111 to form compressed gas stream 113.Then compressed gas stream 113 can be introduced combustion zone 115 together with fuel 112.Optionally, additionally or alternatively the stream 185 comprising a part of fuel (hydrogen) existed in the exhaust of anode 130 can be introduced combustion zone 115.This extra hydrogen can allow combustion reactions to run under the condition strengthened.Then produced hot flue gases or exhaust 117 can be sent into the decompressor part of turbine 110 to generate electric power.

After expansion (with optionally purify and/or other procedure of processing), the stack gas expanded can be sent into the cathode portion 120 of molten carbonate fuel cell.This stack gas can comprise enough for the oxygen of the reaction at negative electrode place, or if necessary, can provide extra oxygen.In order to promote fuel cell reaction, fuel 132 can be sent into together with anode exhaust 135 at least partially the anode part 130 of fuel cell.Before being recycled, can by anode exhaust 135 by several additional technique.A kind of additional technique can comprise or can be water gas shift reaction technique 170.Water gas shift reaction 170 can be used for the H making to exist in anode exhaust 135 ₂o and CO reaction forms extra H ₂and CO ₂.This can allow to improve and remove carbon by anode exhaust 135, because compared with CO, and CO ₂usually can be more easily separated by anode exhaust.Then the output 175 of the water-gas shift technique 170 of (optionally) can be passed through carbon dioxide separating system 140, as deep cooling carbon dioxide separator.This can remove CO at least partially from anode exhaust ₂147, also some water 149 usually.Removing CO at least partially ₂after water, the anode exhaust of recirculation is still containing some CO ₂with water and H ₂and/or possibility hydrocarbon, as the unreacted fuel of methane form.In some embodiments of the present invention, can by from CO ₂second section, to be used as the input stream of anode 130, can be used as the input 185 of combustion reactions 115 by a part 145 recirculation of the output of segregation section simultaneously.Fuel 132 can represent hydrogen stream and/or form H containing methane and/or reformable (inner or outside) ₂the stream of another hydrocarbon.

Then the exhaust of the cathode portion 120 from fuel cell can be sent into heat recovery area 150, so that the recyclable heat from cathode exhaust gas, with such as to vapour generator 160 energy supply.After recovery heat, cathode exhaust gas can be used as exhaust stream 156 and leaves this system.Exhaust stream 156 can be discharged in environment, maybe can use optional additional purification technique, carries out the additional CO on stream 156 as use amine washer ₂trapping.

A kind of method characterizing fuel cell operation can be " utilization ratio " that characterize the various inputs that fuel cell receives.Such as, a kind of common methods characterizing fuel cell operation can be show fuel cell (anode) fuel availability.

Except fuel availability, the utilization ratio of other reactant in fuel cell can be characterized.Such as, in addition or or, can just " CO ₂utilization ratio " and/or " oxygenant " utilization ratio characterize the operation of fuel cell.CO can be specified in a similar manner ₂the value of utilization ratio and/or oxidant utilization.For CO ₂utilization ratio, if CO ₂the sole fuel component being negative electrode input stream or existing in flowing, therefore unique reaction is CO ₃ ^2-formation, then can use (CO ₂-speed-enter-CO ₂-speed-go out)/CO ₂the simplification of-speed-enter calculates.Similarly, for oxidant utilization, if O ₂the sole oxidizing agent being negative electrode input stream or existing in flowing, therefore unique reaction is CO ₃ ^2-formation, then can use this reduced form.

Use another reason of multiple fuel cell may be at the CO by burning and gas-exhausting ₂effective fuel cell operation is allowed while content is down to desired level.While desired level is down in burning, two (or more) fuel cells can be run under comparatively low fuel utilization ratio, but not fuel cell operation is to have height (or best) CO ₂utilization ratio.

Run in the tradition of fuel cell, as in independent operating process, the target of fuel cell operation can generate electric power while effectively utilization is supplied to battery " fuel "." fuel " should can be equivalent to hydrogen (H ₂), hydrogen gas streams and/or comprise the gas streams of the reformable material (as methane, another alkane or the carbon containing of hydrocarbon and/or one or more other types and the compound of hydrogen, they can provide hydrogen when reacting) that hydrogen is provided.These reforming reactions are normally absorbed heat, therefore usual hydrogen produce in consume some heat energy.Also can use and directly and/or when reacting can provide the carbon source of CO, because usually water gas shift reaction (CO+H can be there is under fuel battery anode catalyst surface exists ₂o=H ₂+ CO ₂).This can produce hydrogen by CO source.Such tradition is run, a potential target of fuel cell operation can be exhaust all fuel being supplied to battery, keep the desirable output voltage of fuel cell simultaneously, this is traditionally by fuel cell operation anode under the fuel availability of about 70% to about 75%, and remaining fuel of then burning realizes with the heat generating the temperature keeping fuel cell.

In molten carbonate fuel cell, the electrolytical carbanion transmission striden across in fuel cell can provide from the first flowing-path to the second flowing path transmission CO ₂method, wherein this transmission method can allow from low concentration (negative electrode) to higher concentration (anode) transmit, this can therefore be conducive to trap CO ₂.This fuel cell is to CO ₂the selectivity part be separated can based on the electrochemical reaction that this battery can be made to generate electric power.For the non-reacted thing class of the electrochemical reaction effectively do not participated in fuel cell (as N ₂), unconspicuous reacting weight and the transmission from negative electrode to anode can be there is.On the contrary, current potential (voltage) difference between negative electrode and anode can provide the strong motivating force across fuel cell transmission carbanion.Therefore, the carbanion transmission in molten carbonate fuel cell can allow with relatively high selectivity from negative electrode (lower CO ₂concentration) anode (higher CO ₂concentration) transmit CO ₂.But use a challenge of molten carbonate fuel cell carbon dioxide removal to be, fuel cell has the limited ability removing carbonic acid gas from relatively rare negative electrode charging.Along with CO ₂density loss to about 2.0 below volume %, the voltage generated by carbonate fuel battery and/or power can quick reduction.Along with CO ₂concentration reduces further, such as, drop to about 1.0 below volume %, and at a time, the voltage variable striding across fuel cell obtains enough low so that the further transmission of carbonate almost or completely can not occur and fuel cell.Therefore, under the operational conditions of commericially feasible, at least some CO may be there is in the exhaust of the negative electrode section of fuel cell ₂.

Can based on the CO in cathode inlet source ₂content determines the amount of carbon dioxide being sent to fuel battery negative pole.What be suitable as negative electrode inlet flow contains CO ₂an example of stream can be output from Combustion Source or evacuation circuit.The example of Combustion Source includes, but not limited to the source of the burning based on the burning of Sweet natural gas, burning of coal and/or other hydrocarbon type fuel (comprising biologically-derived fuel).In addition or the source substituted can comprise the boiler of other type, fired heater, stove and/or combust carbonaceous fuel to heat the device of other type of another material (as water or air).Haply, from the CO of the output stream of Combustion Source ₂content can be the secondary part of this stream.Even to higher CO ₂the evacuation circuit of content, the output of Tathagata spontaneous combustion coal Combustion Source, from the CO of most of business coal-fired power plant ₂content can be about 15 volume % or lower.More generally, from the output of Combustion Source or the CO of evacuation circuit ₂content can be at least about 1.5 volume %, or at least about 1.6 volume %, or at least about 1.7 volume %, or at least about 1.8 volume %, or at least about 1.9 volume %, or be at least greater than 2 volume %, or at least about 4 volume %, or at least about 5 volume %, or at least about 6 volume %, or at least about 8 volume %.In addition or or, from the output of Combustion Source or the CO of evacuation circuit ₂content can be about 20 volume % or lower, as about 15 volume % or lower, or about 12 volume % or lower, or about 10 volume % or lower, or about 9 volume % or lower, or about 8 volume % or lower, or about 7 volume % or lower, or about 6.5 volume % or lower, or about 6 volume % or lower, or about 5.5 volume % or lower, or about 5 volume % or lower, or about 4.5 volume % or lower.Concentration given above is based on dry-basis.Point out can there is lower CO in the exhaust from some Sweet natural gases or methyl hydride combustion source (as the generator of a part of power generation system that may comprise or not comprise exhaust gas recycling loop) ₂content value.

The operation of anode part and anode recirculation loop

Of the present invention various in, can allow fuel cell anode part in the condition compared with low fuel utilization ratio under run molten carbonate fuel cell.This tradition that can be different from fuel cell is run, and wherein usually selects fuel availability using make the fuel being sent to fuel cell 70% or more as the part consumption of fuel cell operation.In conventional operation, nearly all fuel can usually fuel cell anode internal consumption or burning to provide obvious heat to the feed steam of fuel cell.

An example of the relation between the fuel availability of the fuel cell that Fig. 3 runs under being presented at tradition (independence) condition and output rating.Figure shown in Fig. 3 shows two kinds of limiting cases of fuel cell operation.A kind of limiting case comprise fuel cell operation with consume be sent to the fuel of fuel cell close to 100% fuel (as H ₂or be reformatted into H ₂methane) limit measured.From standpoint of efficiency, be sent to the fuel of fuel cell ~ 100% consume be desirable, not waste fuel in the operational process of fuel cell.But fuel cell operation is sent to being greater than of the fuel of battery about 80% has two possible shortcomings to consume.First, along with fuel consumption is close to 100%, the voltage provided by this fuel cell can sharply reduce.In order to consume the fuel quantity close to 100%, the fuel concentration in fuel cell (or at least near anode) must by defining almost close to 0 in the operational process at least partially of fuel cell.With gradually 0 the anode of fuel concentration fuel cell operation the motivating force of the electrolyte transport carbonate for striding across fuel cell can be caused gradually low.This can cause the corresponding reduction of voltage, and in the true limiting case of all fuel consuming supply anode, voltage may also close to 0.

The fuel availability value (be greater than about 80%) of second shortcoming also with relatively high is relevant.As shown in Figure 3, under the fuel availability value of about 75% or lower, the voltage produced by fuel cell and fuel availability have substantial linear relation.In figure 3, under about 75% fuel availability, the voltage of generation can be about 0.7 volt.In figure 3, under the fuel availability value of about 80% or higher, voltage reveals exponentially utilization ratio curve table or power type relation.From the angle of technology stability, can preferably wherein this relation voltage linearly to fuel cell operation in utilization ratio curved portion.

In another limiting case in figure 3, along with fuel availability reduces, the voltmeter produced by molten carbonate fuel cell reveals slight raising.But in conventional operation, under the utilization ratio reduced, fuel cell operation can cause all difficulties.Such as, may need to reduce the total fuel quantity be sent to the fuel cell of the tradition run compared with low fuel utilization ratio operation, the heat (when burning further) being suitable for keeping fuel battery temperature still can be provided to make any fuel stayed in anode exhaust/output stream.If reduce fuel availability and do not regulate the fuel quantity being sent to fuel cell, the oxidation of untapped fuel may cause the temperature higher than expectation of fuel cell.At least consider based on these limiting cases, conventional fuel cell runs the thermal equilibrium realizing utilizing completely with fuel usually under the fuel availability of about 70% to about 75%.

Alternative configurations can be by least partially from the exhaust gas recirculatioon of anode of fuel cell to the input of anode of fuel cell.Output stream from MCFC anode can comprise H ₂o, CO ₂, optional CO and optionally but normally unreacted fuel (as H ₂or CH ₄) as mainly exporting component.Replace using this output stream as fuel source with to reforming reaction heat supply, stream can be exported carry out one or many and be separated with by CO by antianode ₂with the component with potential fuel value, as H ₂or CO is separated.Then the component with fuel value can be recycled to the input of anode.

Such configuration can provide one or more benefit.First, CO can be isolated from anode exports ₂, as passed through to use deep cooling CO ₂separator.Several component (H that anode exports ₂, CO, CH ₄) not easy condensed components, and CO ₂and H ₂o can be separated as condensation independently.According to this embodiment, the CO in anode output can be isolated ₂at least about 90 volume %, form relatively high-purity CO ₂export stream.After isolation, the remainder that anode exports mainly can be equivalent to have the component of fuel value and the CO of reducing amount ₂and/or H ₂o.This part anode after separation export can recirculation to be used as a part for anode input together with additional fuel.In this type of configuration, even if the fuel availability in the one way through MCFC may be low, but non-fuel can advantageously recirculation with again through anode.Therefore, the level that one way fuel availability can reduce, avoids the waste of fuel (discharge) that do not fire in environment simultaneously.

By outside a part of anode off-gas recirculation to anode input or alternatively, another config option can be use a part of anode exhaust as the input of the combustion reactions for turbine or other combustion powered source.Be recycled to anode input and/or relative quantity as the anode exhaust of the input of combustion zone can be any convenience or desirable amount.If anode off-gas recirculation is in the only one of anode input and combustion zone, then recirculation volume can be anyly to measure easily, as removing CO ₂and/or H ₂maximum 100% of the part anode exhaust stayed after any separation of O.When a part of anode exhaust had not only been recycled to anode input but also had been recycled to combustion zone, total recirculation volume can be 100% or lower of the remainder of anode exhaust by definition.Or, any of anode exhaust can be used to shunt easily.In the various embodiments of the present invention, the amount being recycled to anode input can be at least about 10%, such as at least about 25%, at least about 40%, at least about 50%, at least about 60%, at least about 75% or at least about 90% of the anode exhaust stayed after being separated.In these embodiments in addition or or, be recycled to anode input amount can for stay after being separated about 90% of anode exhaust or less, such as about 75% or less, about 60% or less, about 50% or less, about 40% or less, about 25% or less or about 10% or less.Again in addition or or, in the various embodiments of the present invention, the amount being recycled to combustion zone (turbine) can be at least about 10%, such as at least about 25%, at least about 40%, at least about 50%, at least about 60%, at least about 75% or at least about 90% of the anode exhaust stayed after being separated.In these embodiments in addition or or, be recycled to combustion zone (turbine) amount can for stay after being separated about 90% of anode exhaust or less, such as about 75% or less, about 60% or less, about 50% or less, about 40% or less, about 25% or less or about 10% or less.

Any H existed in anode exhaust ₂incendivity can be represented and do not produce CO ₂fuel.Because at least some H ₂can be used as a part for the anode part of fuel cell and produce, therefore, the CO produced in reforming process ₂can mainly through the CO in the anode part of system ₂segregation section removes.Therefore, the H of anode exhaust is used ₂part of fuel as combustion reactions can allow such situation: can occur the CO produced by fuel " burning " in the anode part of system ₂, instead of must by CO ₂be conveyed through film.

By the H of anode exhaust ₂be recycled to combustion reactions to can be the turbine (or other firing system) comprising exhaust gas recirculatioon (EGR) and configure synergistic benefits is provided.In EGR configuration, can the part of in the future auto-combustion reaction containing CO ₂exhaust gas recirculatioon and be used as the part of input air-flow of turbine.In the operational process of the turbine of burning energy supply, oxygenant can be inputted air-flow (as air or oxygen-rich air) and compress before introducing combustion reactions.The compressor used to the inlet flow of combustion reactions can tend to be volume restriction, and therefore the usual quality regardless of gas how, the gas of compressible similar mole number.But the gas with better quality can tend to the pressure ratio having higher heat capacity and/or can allow the larger decompressor part across turbine.Rich CO ₂exhaust stream the convenient source of the gas streams with higher molecu lar weight component can be provided, this can allow the energy of combustion reactions to change into the improvement of electric power by turbine.Although by rich CO ₂stream introduce combustion reactions some benefits can be provided, but on significantly (negative) affect combustion reactions and the rich CO that adds ₂stream amount can there is effective restriction.Due to rich CO ₂stream itself usually not containing " fuel ", therefore this stream can serve as the thinner in combustion reactions to a great extent.Therefore, can at least in part based on the condition in combustion reactions being remained on the CO limiting recirculation in suitable flammability range ₂amount.

The H of anode exhaust ₂recirculation can supplement in one or more ways EGR configuration.First, H ₂burning directly can not cause CO ₂generation.On the contrary, as noted, at H processed ₂time produce CO ₂can occur in plate tank.For given power generation level, this can reduce needs by the CO of cathode transport to anode ₂amount.Additionally, H ₂also can having the benefit improved Combustion Source and run, as by improving flammability range, therefore can allow higher CO while still keeping required combustion reactions ₂concentration.The ability of expansion flammability range can make the CO increased in burning and gas-exhausting ₂concentration, and the CO therefore making the increase in fuel battery negative pole input ₂become possibility.

The CO in fuel battery negative pole input can be improved ₂the benefit of concentration can be relevant with the essence how molten carbonate fuel cell runs.As will be described in further detail below, for the CO that can be separated by cathode exhaust gas stream by MCFC ₂amount can there is physical constraints.Depend on operational conditions, MCFC can by the CO of cathode exhaust gas stream ₂content is reduced to about 2.0 volume % or lower, such as about 1.5 volume % or lower or about 1.2 volume % or lower.Due to this restriction, use CO during molten carbonate fuel cell ₂remove net efficiency can be depending on negative electrode input in CO ₂amount.For the combustion reactions using Sweet natural gas as fuel, the CO in burning and gas-exhausting ₂amount may correspond in the CO in negative electrode input ₂concentration is at least about 4 volume %.The use of exhaust gas recirculatioon can make the CO of negative electrode input ₂amount brings up at least about 5 volume %, such as at least about 6 volume %.Owing to using H ₂as the flammability range of available increase during fuel a part of, the CO added via exhaust gas recirculatioon ₂amount can further improve, therefore can realize the CO of negative electrode input ₂concentration is at least about 7.5 volume % or at least about 8 volume %.Based on cathode exhaust gas place about 1.5 volume % remove the limit, by the CO of negative electrode input ₂content is increased to about 7.5 volume % by about 5.5 volume % and is equivalent to use fuel cell can trap and transfer to plate tank for final CO ₂the CO be separated ₂content increases ~ 50%.

Can such as by use water-gas shift will anode export in exist H ₂o and CO changes into H ₂and CO ₂improve during anode exports the H existed ₂amount.Water is that the expection of the reaction occurred at anode place exports, therefore this anode export usually can have export with anode in the CO that exists measure compared with excessive H ₂o.Due to the incomplete carbon burning in reforming process and/or due to the condition of reorganization or in anodic reaction process H under existent condition ₂o, CO, H ₂and CO ₂between balanced reaction (i.e. water gas shift equilibrium), anode export in can there is CO.Water-gas shift can with CO and H ₂o is that cost is further towards formation CO ₂and H ₂direction drive the condition of this balance under run.Comparatively high temps may often be conducive to forming CO and H ₂o.Therefore, running an option of water-gas shift can be in suitable temperature, such as, makes anode output stream be exposed to suitable catalyzer at about 190 DEG C to about 210 DEG C, as comprise ferric oxide, zinc oxide, copper/zinc oxide etc. catalyzer under.This water-gas shift optionally can comprise two sections exporting the CO concentration in stream for reducing anode, wherein the first higher temperatures section is run at the temperature of at least about 300 DEG C to about 375 DEG C, second comparatively low-temperature zone at about 225 DEG C or lower, as run at the temperature of about 180 DEG C to about 210 DEG C.Except improving during anode exports the H existed ₂outside amount, this water gas shift reaction can also be that cost improves CO with CO ₂amount.The carbon monoxide (CO) that difficulty removes can be transformed into carbonic acid gas by this, and carbonic acid gas can pass more readily condensation (such as deep cooling removes), chemical reaction (as amine removal) and/or other CO ₂removal method removes.

In some aspects of the invention, can by separation (part) CO ₂all or substantially all anodes remaining after (and water) export stream recirculation, as the input of anode of fuel cell or the fuel input as burning energy supply generator.Therefore, at water gas shift reaction, CO ₂remove and/or H ₂part anode remaining after O removes exports stream, and at least about 90% of residue content can be advantageously used for the input of anode of fuel cell anode or be used as the fuel input of burning energy supply generator.Or the anode after separation exports stream and can be used for more than one object, but the anode of any part can be advantageously avoided to export stream recirculation as the direct input of negative electrode and/or the input as the oxidizer for heating fuel battery.

Fig. 4 display is according to an example of the anode flow part of generator/fuel cell system of the present invention.In the diagram, initial fuel stream 405 optionally can reform 410 so that methane (or fuel of another type) and water are changed into H ₂and CO ₂.Or, reforming reaction can be carried out in the reforming sections of a part being the assembly comprising reforming sections and anode of fuel cell 420.In addition or or, fuel streams 405 can be equivalent to hydrogen at least partially, so as can to reduce and/or to greatest extent reduce anode 420 amount of the reformation needed for fuel is provided.Then this fuel 415 optionally reformed can be sent into anode 420.The recycle stream 455 comprising fuel element from anode exhaust 425 also can serve as the input of anode 420.Carbanion stream 422 from the cathode portion (not shown) of fuel cell can provide the remaining reaction thing needed for anode fuel cell reaction.Based on the reaction in anode 420, gained anode exhaust 425 can comprise H ₂o, CO ₂, be equivalent to one or more components (H of unreacted fuel ₂, CO, CH ₄or other) and choose any one kind of them or multiple additional non-reactive component, as N ₂and/or be other pollutent of a part of fuel streams 405.Then anode exhaust 425 can be sent into one or more segregation section 430 to remove CO ₂(and optional H ₂o).Deep cooling CO ₂the system of removing can be an example of the suitable type of segregation section.Optionally, anode exhaust can first through water-gas shift 440 with any CO will existed in anode exhaust (with some H ₂o is together) change into CO in the anode exhaust 445 of optional water-gas shift ₂and H ₂.

The initial portion of segregation section 430 can be used for removing the most of H existed in anode exhaust 425 ₂o, as H ₂o exports stream 432.In addition or or, can use independent of the heat recovery steam generator system of low temperature separation process system or other interchanger to remove a part of H ₂o.Deep cooling CO ₂remove system and then can remove most of CO ₂, as high-purity CO ₂stream 434.If needed, also can there is purging stream (not shown) and accumulate in anode recirculation loop to prevent rare gas element.Then can by the remaining ingredient of anode exhaust stream as being recycled to the input 455 of anode 420 entrance or being used as the input stream 485 of burning energy supply turbine.

Conventionally, before any fuel enters fuel cell, at least some reformation is carried out.This is initial/preliminary reforms and can carry out in the reformer of fuel cell or fuel cell pack outside.Or the assembly for fuel cell pack can comprise and is arranged in heap but or multiple reformer section before the anode of the fuel cell of heap.At least some fuel was changed into hydrogen by this initial reformate usually before entering anode, and the stream therefore entering anode can have the hydrogen being enough to maintain anodic reaction.In certain embodiments, when not this initial reformate, the hydrogen content in anode may be too low, causes few or do not have CO ₂from cathode transport to anode.Unlike this, in some embodiments, the fuel cell in fuel cell array can run when not having outside reformation, namely, only based on the reformation in anode of fuel cell part, this is owing to there is enough hydrogen in the recycling part of anode exhaust.When there is the H of q.s in anode feed ₂time, at least about 10 volume % being delivered to the fuel of anode are H ₂form, the reaction conditions in anode can allow amount in anode itself to reform outward, depends on flowing-path, and this can reduce and/or eliminate the demand of the reforming sections of antianode input outside (before) in the method according to the invention.If anode feed is containing the hydrogen of q.s, then anodic reaction may stop, and other reaction in reforming activity and/or anode can be lowered, minimizes or interrupt completely.Therefore, the H existed in anode feed ₂in the embodiment of quantity not sufficient, may desirable (or required) be the reforming sections that there is anode input outside (before).

The operation of cathode portion

According to of the present invention various in, molten carbonate fuel cell for carbon trapping can be run to improve or to strengthen the carbon trapping aspect of this fuel cell, but not (or even sacrificing) strengthens power generation capacity.Traditionally, desired voltage can be provided to run molten carbonate fuel cell based on while consuming all fuel be sent in the fuel streams of anode.This can traditionally partly by using anode exhaust as negative electrode input stream realization at least partially.On the contrary, antianode of the present invention input and negative electrode input use and separate/different source.By eliminating the contact between anode inlet flow and the composition of negative electrode inlet flow, the additional option for fuel cell operation becomes available, to improve the trapping of carbonic acid gas.

Use an initial challenge in molten carbonate fuel cell removing carbonic acid gas can be that this fuel cell has the limited ability removing carbonic acid gas from relatively rare negative electrode charging.Fig. 5 is based on the CO in negative electrode input gas ₂concentration display 1) voltage and CO ₂concentration and 2) power and CO ₂an example of the relation between concentration.As shown in Figure 5, along with CO ₂density loss to about 2.0 below volume %, the voltage produced by carbonate fuel battery and/or power can quick reduction.Along with CO ₂concentration reduces further, such as, drop to about 1.0 below volume %, and at certain a bit, the voltage striding across fuel cell becomes enough low so that the further transmission of carbonate almost or completely can not occur.Therefore, at least some CO may be there is in the exhaust of the negative electrode section from fuel cell ₂, almost have nothing to do with operational conditions.

An amendment of fuel cell operating conditions can be utilize the excessive available reactant fuel cell operation at anode place, as passed through to run with the low fuel utilization ratio at anode place as mentioned above.By providing excessive reactant for the anodic reaction in fuel cell, for the CO of cathodic reaction ₂availability can be used as the speed limit variable of this reaction.

When running MCFCs to strengthen carbon amount of collected, when balance factor can be different from and attempt improving fuel availability.Especially, can based on from providing containing CO ₂the output stream of the burning generators of stream determines the amount of carbon dioxide being sent to fuel cell.Haply, from the CO of the output stream of burning generators ₂content can be the secondary part of this stream.Even if to higher CO ₂the evacuation circuit of content, the output of Tathagata spontaneous combustion coal burning generators, from the CO of most of business coal-fired power plant ₂content can be about 15 volume % or lower.In order to carry out cathodic reaction, this may comprise about 5% to about 15% potentially, usually about 7% to about 9% for CO ₂reaction forms the oxygen of carbanion.Therefore, cathodic reaction usually can consume negative electrode input stream less than about 25 volume %.All the other parts of at least about 75% of cathode system can by inertia/non-reacted thing class, as N ₂, H ₂o and other typical oxygenant (air) component and any unreacted CO ₂and O ₂form.

Relative to cathodic reaction, based on the character of negative electrode inlet flow, for based on comparatively clean fuel source, as the inlet flow of the burning of gas source, can be about 25 volume % or lower in the negative electrode importation of cathode consumption and removing, such as about 10 volume % or lower.(such as, in Sweet natural gas, usually N can be there is with little per-cent in exact amount based on fuel used, the amount of diluent inputted in fuel ₂) and run oxygenant (the air)/fuel ratio (all these is variable but usually comercial operation is known) of burner and become.Therefore, at the total fuel cell array trapped for carbon, enter the total air flow relatively measurable (constant) of the cathode portion of fuel cell.Several possible fuel cell array being configured to be provided for enhancing/improvement/optimization carbon trapping can be used.Following config option can alone or the combination part of strategy making improvements carbon trapping.

Typical Disposition option can be to contain CO ₂stream split between multiple fuel cell.Relative to the desirable operational conditions of single MCFC of Sizes, from industrial generator containing CO ₂output stream usually can be equivalent to large discharge volume.Replace processing whole stream in single MCFC, this stream can be split between multiple MCFC unit, wherein at least some usually can be in parallel, to make flow velocity in each unit within the scope of required flow rate.

In addition or or, can connect utilize fuel cell with from flowing stream in succession remove CO ₂.No matter contain CO ₂the initial fuel cell number that stream can in parallel be assigned to is how many, can be that one or more balancing cells of series connection are to remove extra CO further after each initial fuel cell ₂.Be similar to the H of antianode in Fig. 3 ₂input illustrative situation, attempt the CO removed in single fuel cell in stream ₂low and/or uncertain voltage can be caused to export.Be different from and attempt removing CO in single fuel cell ₂to desired level, CO can be removed in continuous print battery ₂until can desired level be realized.Such as, each battery in a succession of fuel cell can be used for the CO removing the certain percentage (such as about 50%) existed in fuel streams ₂.In such instances, if series connection use three fuel cells, CO can be reduced ₂(be such as down to about 15% or lower of original amount, this process that can be equivalent to three fuel cells through connecting is by CO for concentration ₂concentration is down to about 1% or lower from about 6%).

Further in addition or or, can operational conditions be selected to provide required output voltage in the comparatively early fuel section of series connection, simultaneously can the section of selection array to realize required carbon trapping level.Such as, the fuel cell array of three fuel cells with series connection can be used.Removing CO while the first two fuel cell of series connection is used in and keeps required output voltage ₂.Then last fuel cell can be run to remove CO ₂to desired concn.

Further in addition or or, the anode in fuel cell array can be connected separately with negative electrode.Such as, if fuel cell array comprises the fuel cell cathode of series connection, corresponding anode can connect in any convenient manner, and layout that need not be identical with their respective cathode matches.This can comprise, and such as, is connected in parallel anode, with the fuel-feed making each anode receive identical type, and/or differential concatenation jointed anode, may correspond in having minimum CO to make the highest fuel concentration in anode ₂those negative electrodes of concentration.

Hydrogen or synthetic gas trapping

Can be used as chemical energy output from anode exhaust, extract hydrogen or synthetic gas.Hydrogen can be used as the clean fuel not generating greenhouse gases when burning.Otherwise, for the hydrogen that the reformation by hydrocarbon (or hydrocarbon matter compound) generates, by CO ₂" trapping " is in plate tank.In addition, hydrogen can be the valuable input for various refinery processes and/or other synthesis technique.Synthetic gas may also be for polytechnic valuable input.Except having fuel value, synthetic gas also can be used as the raw material for the production of other more high-value product, such as, by using synthetic gas as the input of F-T synthesis and/or methanol synthesizing process.

In in various, anode exhaust can have about 1.5:1 to about 10:1, as at least about 3.0:1, or at least about 4.0:1, or at least about 5.0:1, and/or the H of about 8.0:1 or lower or about 6.0:1 or lower ₂/ CO ratio.Synthetic gas stream can be taken out from anode exhaust.In in various, the synthetic gas stream taken out from anode exhaust can have at least approximately 0.9:1, as at least about 1.0:1, or at least about 1.2:1, or at least about 1.5:1, or at least about 1.7:1, or at least about 1.8:1, or the H of at least about 1.9:1 ₂the ratio of mole number and CO mole number.In addition or or, the H of the synthetic gas taken out from anode exhaust ₂/ CO mol ratio can be about 3.0:1 or lower, as about 2.7:1 or lower, or about 2.5:1 or lower, or about 2.3:1 or lower, or about 2.2:1 or lower, or about 2.1:1 or lower.Point out, H higher in the synthetic gas stream of taking-up ₂/ CO is than tending to relative to the CO in cathode exhaust gas ₂amount reduces CO amount.But, permitted the H that the application of eurypalynous synthetic gas benefits to have at least approximately 1.5:1 to about 2.5:1 or lower ₂the synthetic gas of/CO mol ratio, therefore forms the H with such as approximately 1.7:1 to about 2.3:1 ₂the synthetic gas stream of/CO content mol ratio may be desirable for some application.

Synthetic gas can be taken out from anode exhaust by any method easily.In certain aspects, can be undertaken being separated removing by antianode exhaust and be different from H at least partially in anode exhaust ₂from anode exhaust, synthetic gas is taken out with the component of CO.Such as, anode exhaust can first be made through optional water gas shift stage to regulate H ₂with the relative quantity of CO.Then one or more segregation section can be used from anode exhaust to remove H ₂o and/or CO ₂.The remainder of anode exhaust can be equivalent to synthetic gas stream subsequently, and it can take out for use subsequently in any convenient manner.In addition or or, the synthetic gas stream of taking-up can be made through one or more water gas shift stage and/or through one or more segregation section.

Point out, change the H in the synthetic gas taken out ₂additional or the substituting mode of/CO mol ratio can be isolate H from anode exhaust and/or synthetic gas ₂stream, such as, by carrying out membrane sepn.Form independent H ₂export stream this separation can in office what carry out position easily, as made anode exhaust before or after water gas shift reaction section, and make anode exhaust be different from H to remove in anode exhaust through one or more segregation section ₂before or after the component of CO.Optionally, H can be separated from anode exhaust ₂water gas shift stage is used before and after stream.Add at one or in substituting embodiment, optionally can be separated H from the synthetic gas stream taken out ₂.In certain aspects, the H of separation ₂stream can be equivalent to high-purity H ₂stream, as the H containing at least about 90 volume % ₂, as the H of at least about 95 volume % ₂or the H of at least about 99 volume % ₂h ₂stream.

In certain aspects, can use there is medium or low CO ₂the negative electrode input charging of content runs molten carbonate fuel cell.Be applicable to carbon be separated and the various streams of trapping can comprise have medium to low CO ₂the stream of content.Such as, the possible input stream of cathode inlet can have about 20 volume % or lower, as about 15 volume % or lower, or about 12 volume % or lower, or the CO of about 10 volume % or lower ₂content.This containing CO ₂stream can by burning generators, and the turbine as fire coal or gas-firing produces.Based on having medium or low CO ₂the negative electrode input stream of content realizes required CO ₂utilize level can allow to use the CO of lower aq ₂stream, and do not need to make this stream enrichment CO before this stream of use is as negative electrode input stream ₂.In in various, the CO of fuel cell ₂utilization ratio can be at least about 50%, as at least about 55% or at least about 60%.In addition or or, CO ₂utilization ratio can be about 98% or lower, as about 97% or lower, or about 95% or lower, or about 90% or lower, or can just be high enough to make enough CO ₂stay in cathode exhaust gas to allow fuel cell effectively or as required to run.CO used herein ₂utilization ratio can be the CO in cathode outlet stream ₂cO in mole number and cathode inlet stream ₂the difference of mole number is divided by the CO in cathode inlet ₂mole number.Express with mathematical way, CO ₂utilization ratio=(CO _{2 (negative electrode inputs)}-CO _{2 (negative electrode outputs)})/CO _{2 (negative electrode inputs)}.

Operation reserve

As the increase to fuel cell operation strategy described herein, supplement and/or substitute, in reduction or can will leave the CO of fuel cell in cathode exhaust gas stream ₂molten carbonate fuel cell (as fuel cell module) is run with synthetic gas (or hydrogen) output improved while amount minimizes.Synthetic gas can be for polytechnic valuable input.Except having fuel value, synthetic gas also can be used as the starting material for the formation of other more high-value product, such as, by using synthetic gas as the input of F-T synthesis and/or methanol synthesizing process.An option for the manufacture of synthetic gas can be reforming hydrocarbon or class hydrocarbon fuel, as methane or Sweet natural gas.For being permitted eurypalynous industrial technology, there is the H close to 2:1 (or even lower) ₂the synthetic gas of/CO ratio can be normally desirable.If there is extra CO ₂available, as the CO produced at anode ₂, then the H in water gas shift reaction reduction synthetic gas can be utilized ₂/ CO ratio.

By synthetic gas to be generated and the integrated and a kind of characteristic manner of overall efficiency that provides of the use of molten carbonate fuel cell can based on leaving the net amount of synthetic gas of fuel cell relative to the CO leaving fuel cell in cathode exhaust gas in anode exhaust ₂the ratio of amount.This effect characterizing measurement and generate electricity with low emission and high-level efficiency (electricity and chemistry).In this manual, the net amount of the synthetic gas in anode exhaust is defined as the H existed in anode exhaust ₂the summation of mole number and CO mole number deducts the H of anode inlet existence ₂measure with CO.Because this ratio is based on the net amount of the synthetic gas in anode exhaust, simply by excessive H ₂send into the value that anode can not change this ratio.But, the H generated owing to reforming in the anode and/or in the inside reforming section relevant to anode ₂and/or CO can cause the much higher value of this ratio.The hydrogen be oxidized in the anode can reduce this ratio.Point out, water gas shift reaction can use H ₂exchange CO, therefore H ₂the total potential synthetic gas in anode exhaust is represented, no matter final required H in synthetic gas with the total mole number of CO ₂/ CO ratio how.Then can by the synthetic gas content (H of anode exhaust ₂+ CO) with the CO of cathode exhaust gas ₂content is compared.This can provide the efficiency value of a type, and it also can illustrate (accountfor) carbon amount of collected.This can be expressed as equation comparably

Clean synthetic gas in anode exhaust and negative electrode CO ₂ratio=

(H ₂+ CO) _anodeclean mole number/(CO ₂) _{negative electrode}mole number

In in various, the CO in the clean mole number of the synthetic gas in anode exhaust and cathode exhaust gas ₂the ratio of mole number can be at least about 2.0, as at least about 3.0, or at least about 4.0, or at least about 5.0.In certain aspects, the clean synthetic gas in anode exhaust and the CO in cathode exhaust gas ₂the ratio of amount can be higher, as at least about 10.0, or at least about 15.0, or at least about 20.0.In addition or or, about 40.0 or lower can be realized, as about 30.0 or lower, or the rate value of about 20.0 or lower.At the CO at cathode inlet place ₂amount is for about 6.0 volume % or lower, and in the aspect as about 5.0 volume % or lower, the rate value of at least about 1.5 may enough/reality.Clean synthetic gas in anode exhaust and the CO in cathode exhaust gas ₂this molar ratio value of amount can higher than the value of the fuel cell run according to tradition.

As the increase to fuel cell operation strategy described herein, supplement and/or substitute, molten carbonate fuel cell (as fuel cell module) can run under the fuel availability value reduced is as the fuel availability of about 50% or lower, also has high CO simultaneously ₂utilization ratio value, as at least about 60%.In this type of configuration, this molten carbonate fuel cell can be effective to carbon trapping, because CO ₂utilization ratio can be advantageously enough high.Be different from and attempt electrical efficiency is maximized, can improve based on comprehensive electricity and chemical efficiency or improve the total efficiency of this fuel cell in this type of configuration.Chemical efficiency can based on as exporting the hydrogen that takes out from anode exhaust and/or synthetic gas stream for other technique.Although electrical efficiency may be lowered compared with some conventional arrangement, the chemical energy in anode exhaust is utilized to export the desirable total efficiency that can realize fuel cell.

In in various, the fuel availability in anode of fuel cell can be about 50% or lower, as about 40% or lower, or about 30% or lower, or about 25% or lower, or about 20% or lower.In in various, in order to generate at least some electric power, the fuel availability in this fuel cell can be at least about 5%, as at least about 10%, or at least about 15%, or at least about 20%, or at least about 25%, or at least about 30%.In addition or or, CO ₂utilization ratio can be at least about 60%, as at least about 65%, or at least about 70%, or at least about 75%.

As the increase to fuel cell operation strategy described herein, supplement and/or substitute, can molten carbonate fuel cell be run so that can relative to amount of oxidation selectoforming amount to realize thermal ratio needed for fuel cell." thermal ratio " used herein is defined as by the heat absorption demand of the heat of the thermopositive reaction generation in fuel cell module divided by the reforming reaction occurred in fuel cell module.Express with mathematical way, thermal ratio (TH)=Q _eX/ Q _eN, wherein Q _eXthe heat summation and Q that are generated by thermopositive reaction _eNit is the heat summation that the thermo-negative reaction occurred in fuel cell consumes.Point out, the heat generated by thermopositive reaction is equivalent to any heat owing to the reforming reaction in this battery, water gas shift reaction and electrochemical reaction.The actual output voltage that can deduct fuel cell based on the desired electrochemical gesture striding across electrolytical fuel cell reaction calculates the heat generated by electrochemical reaction.Such as, based on the clean reaction occurred in the battery, the desired electrochemical gesture of the reaction thought in MCFC is about 1.04V.In the operational process of MCFC, due to various loss, this battery has the output voltage being less than 1.04V usually.Such as, common output/operating voltage can be about 0.7V.The electrochemical potential (namely ~ 1.04V) that the heat generated equals this battery deducts operating voltage.Such as, when output voltage be ~ 0.7V time, by battery electrochemical reaction generate heat be ~ 0.34V.Therefore, in this case, the electricity of electrochemical reaction generation ~ 0.7V and the heat energy of ~ 0.34V.In such instances, the electric energy of ~ 0.7V is not as Q _eXa part.In other words, heat energy is not electric energy.

In in various, can to any fuel cell structure easily, as the individual fuel cell in fuel cell pack, fuel cell pack, the fuel cell pack with integrated reforming sections, the fuel cell pack with integrated thermo-negative reaction section or its combine measured thermal ratio.Also can to the different units in fuel cell pack, as the Assembly calculation thermal ratio of fuel cell or fuel cell pack.Such as, thermal ratio can be calculated to the anode segment in the single anode in single fuel cell, the anode segment in fuel cell pack or the fuel cell pack together with integrated reforming sections and/or integrated thermo-negative reaction segment element (enough closely near wanting integrated anode segment viewed from hot integrated angle)." anode segment " used herein is included in multiple anodes of share common entrance in fuel cell pack or outlet manifold.

Of the present invention various in, the operation of fuel cell can be characterized based on thermal ratio.If fuel cell operation is to have required thermal ratio, then can run molten carbonate fuel cell to have about 1.5 or lower, such as about 1.3 or lower, or about 1.15 or lower, or about 1.0 or lower, or about 0.95 or lower, or about 0.90 or lower, or about 0.85 or lower, or about 0.80 or lower, or the thermal ratio of about 0.75 or lower.In addition or or, thermal ratio can be at least about 0.25, or at least about 0.35, or at least about 0.45, or at least about 0.50.In addition or or, in certain aspects, can fuel cell operation to have about 40 DEG C or less, as about 20 DEG C or less, or about 10 DEG C or less anode input and anode export between intensification.Again in addition or or, can fuel cell operation with the anode export temperature with lower than anode inlet temperature about 10 DEG C paramount about 10 DEG C.Again in addition or or, can fuel cell operation to have the anode inlet temperature higher than anode export temperature, as at least about in height 5 DEG C, or at least about 10 DEG C of height, or at least about 20 DEG C of height, or at least about 25 DEG C of height.Again in addition or or, can fuel cell operation higher than anode export temperature about 100 DEG C or lower to have, as about in height 80 DEG C or lower, or about 60 DEG C or lower, or about 50 DEG C or lower, or about 40 DEG C or lower, or about 30 DEG C or lower, or the anode inlet temperature of about 20 DEG C or lower.

As the increase to fuel cell operation strategy described herein, supplement and/or substitute, can with the reformable operating fuel molten carbonate fuel cell (as fuel cell module) excessive relative to the hydrogen amount of reacting in the anode of fuel cell.Replace selecting the operational conditions of fuel cell improve or the electrical efficiency of fuel cell is maximized, the anode excessive reformable fuel can being sent into fuel cell exports with the chemical energy improving fuel cell.Optionally but preferably, this can cause improving based on the comprehensive electrical efficiency of fuel cell and the fuel cell total efficiency of chemical efficiency.

In certain aspects, being sent to anode and/or being sent to the reformable hydrogen richness of the reformable fuel in the input stream of the reforming sections relevant to anode can than the hydrogen amount height at least about 50% be oxidized in the anode, as height at least about 75% at least about 100%.In in various, the reformable hydrogen richness of the reformable fuel in fuel streams and the ratio of the hydrogen amount of reacting in the anode can be at least about 1.5:1, or at least about 2.0:1, or at least about 2.5:1, or at least about 3.0:1.In addition or or, the reformable hydrogen richness of the reformable fuel in fuel streams can be about 20:1 or lower with the ratio of the hydrogen amount of reacting in the anode, as about 15:1 or lower or about 10:1 or lower.On the one hand, estimate that being less than of the reformable hydrogen richness in anode inlet stream 100% can change into hydrogen.Such as, at least about 80% of the reformable hydrogen richness in anode inlet stream can change into hydrogen in the anode and/or in relevant reforming sections, as at least about 85%, or at least about 90%.

As the increase to fuel cell operation strategy described herein, supplement and/or substitute, also can run molten carbonate fuel cell (as fuel cell module) under the condition of the comprehensive electrical efficiency and chemical efficiency that can improve or optimize fuel cell.Replace selecting for making the maximized conventional conditions of the electrical efficiency of fuel cell, this operational conditions can export excess syngas and/or hydrogen in the anode exhaust of fuel cell.Then this synthetic gas and/or hydrogen can be used for various application, comprise chemical synthesis process and collect hydrogen to be used as " cleaning " fuel.In in of the present invention, can reduce electrical efficiency to realize high total efficiency, this comprises chemical efficiency, the relative value of its Energy value inputted based on the synthetic gas generated and/or the chemical energy value of hydrogen and the fuel of fuel cell.

In certain aspects, the operation of fuel cell can be characterized based on electrical efficiency.If fuel cell operation is to have low electrical efficiency (EE), molten carbonate fuel cell can be run with the electrical efficiency with about 40% or lower, such as about 35%EE or lower, about 30%EE or lower, about 25%EE or lower, or about 20%EE or lower, about 15%EE or lower, or about 10%EE or lower.In addition or or, EE can be at least about 5%, or at least about 10%, or at least about 15%, or at least about 20%.Again in addition or or, can based on total fuel cell efficiency (TFCE), as the comprehensive electrical efficiency of fuel cell and chemical efficiency characterize the operation of fuel cell.If fuel cell operation is to have high total fuel cell efficiency, molten carbonate fuel cell can be run to have about 55% or larger, such as about 60% or larger, or about 65% or larger, or about 70% or larger, or about 75% or larger, or about 80% or larger, or the TFCE of about 85% or larger (and/or comprehensive electrical efficiency and chemical efficiency).Point out, for total fuel cell efficiency and/or comprehensive electrical efficiency and chemical efficiency, any additional power of the excessive heat generation utilizing fuel cell to generate can not be comprised in efficiency calculation.

Of the present invention various in, the operation of fuel cell can be characterized based on total fuel cell efficiency needed for electrical efficiency and about 55% or larger needed for about 40% or lower.If fuel cell operation is to have required electrical efficiency and required total fuel cell efficiency, molten carbonate fuel cell can be run to have the electrical efficiency of about 40% or lower and the TFCE of about 55% or larger, the such as TFCE of about 35%EE or lower and about 60% or larger, the TFCE of about 30%EE or lower and about 65% or larger, about 25%EE or lower and about 70%TFCE or larger, or the TFCE of about 20%EE or lower and about 75% or larger, the TFCE of about 15%EE or lower and about 80% or larger, or the TFCE of about 10%EE or lower and about 85% or larger.

As the increase to fuel cell operation strategy described herein, supplement and/or substitute, molten carbonate fuel cell (as fuel cell module) can be run under the condition of power density that raising can be provided.The power density of fuel cell is equivalent to real work voltage V _abe multiplied by current density I.For at voltage V _athe molten carbonate fuel cell of lower operation, this fuel cell also tends to generate used heat, used heat is defined as (V ₀– V _a) * I, it is based on V _awith the desired voltage V of fuel cell providing current density I ₀difference.The reformation of reformable fuel in the anode of fuel cell can consume a part of this used heat.This used heat of remainder can be absorbed by the fuel cell structure of surrounding and air-flow, causes the temperature head across fuel cell.Under traditional operational conditions, the power density of fuel cell can be restricted based on fuel cell permissible waste heat when not damaging fuel cell integrity.

In in various, by carrying out the thermo-negative reaction of significant quantity in fuel cell, the permissible waste heat of fuel cell can be improved.An example of thermo-negative reaction comprises reformable fuel in anode of fuel cell and/or in relevant reforming sections, as the steam reformation in the integrated reforming sections in fuel cell pack.There is provided extra reformable fuel by the anode (or to integrated/relevant reforming sections) to fuel cell, can extra reformation be carried out extra used heat can be consumed.This can reduce the amount of the temperature head across fuel cell, allows fuel cell to run under the operational conditions of waste heat with raising thus.The loss of electrical efficiency is offset by producing the additional product stream that can be used for various uses (comprising extra generating), and described additional product stream is such as synthetic gas and/or H ₂, to expand the power range of this system further.

In in various, the waste heat that fuel cell generates, as defined above (V ₀– V _a) * I can be at least about 30mW/cm ², as at least about 40mW/cm ², or at least about 50mW/cm ², or at least about 60mW/cm ², or at least about 70mW/cm ², or at least about 80mW/cm ², or at least about 100mW/cm ², or at least about 120mW/cm ², or at least about 140mW/cm ², or at least about 160mW/cm ², or at least about 180mW/cm ².In addition or or, fuel cell generate waste heat can be less than about 250mW/cm ², as being less than about 200mW/cm ², or be less than about 180mW/cm ², or be less than about 165mW/cm ², or be less than about 150mW/cm ².

Although the waste heat generated may be relatively high, such used heat does not necessarily represent fuel cell and runs to differ from efficiency.On the contrary, can due to fuel cell operation and generate used heat under the power density improved.The part of power density improving fuel cell can be included in fuel cell operation under sufficiently high current density.In in various, the current density that fuel cell generates can be at least about 150mA/cm ², as at least about 160mA/cm ², or at least about 170mA/cm ², or at least about 180mA/cm ², or at least about 190mA/cm ², or at least about 200mA/cm ², or at least about 225mA/cm ², or at least about 250mA/cm ².In addition or or, fuel cell generate current density can be about 500mA/cm ²or lower, as 450mA/cm ²or lower, or 400mA/cm ²or lower, or 350mA/cm ²or lower, or 300mA/cm ²or it is lower.

In in various, in order to can under the used heat of the generating improved and raising generates fuel cell operation, the thermo-negative reaction (as reforming reaction) of significant quantity can be carried out.Or, use other thermo-negative reaction running with anode and have nothing to do to utilize used heat by arranging " plate " that with male or female thermal communication but not fluid is communicated with or section in fuel cell array.The thermo-negative reaction of significant quantity can in relevant reforming sections, integrated reforming sections, carry out in the integrated Nuclear fuel of thermo-negative reaction or its combination for carrying out.The thermo-negative reaction of significant quantity can be equivalent to be enough to the intensification from fuel cell inlet to fuel exit is decreased to about 100 DEG C or lower, as about 90 DEG C or lower, or about 80 DEG C or lower, or about 70 DEG C or lower, or about 60 DEG C or lower, or about 50 DEG C or lower, or about 40 DEG C or lower, or about 30 DEG C or lower amount.In addition or or, the thermo-negative reaction of significant quantity can be equivalent to be enough to make the cooling from fuel cell inlet to fuel exit be about 100 DEG C or lower, as about 90 DEG C or lower, or about 80 DEG C or lower, or about 70 DEG C or lower, or about 60 DEG C or lower, or about 50 DEG C or lower, or about 40 DEG C or lower, or about 30 DEG C or lower, or about 20 DEG C or lower, or about 10 DEG C or lower amount.When the thermo-negative reaction of significant quantity exceedes the used heat of generation, the cooling from fuel cell inlet to fuel exit can be there is.In addition or or, this can be equivalent at least about 40% of the used heat that thermo-negative reaction (as reformation and the combination of another thermo-negative reaction) consume fuel battery generates, as consumed the used heat of at least about 50%, or the used heat of at least about 60%, or the used heat of at least about 75%.Again in addition or or, thermo-negative reaction can consume about 95% or less used heat, as about 90% or less used heat, or about 85% or less used heat.

definition

Synthetic gas: in this manual, synthetic gas is defined as H ₂with the mixture of any ratio of CO.Optionally, H ₂o and/or CO ₂can be present in synthetic gas.Optionally, inert compound (as nitrogen) and residual reformable fuel compound can be present in synthetic gas.If H ₂be present in synthetic gas with the component beyond CO, H in synthetic gas ₂with at least 25 volume % that the total volume percent of CO can be synthetic gas cumulative volume, as at least 40 volume %, or at least 50 volume %, or at least 60 volume %.In addition or or, H in synthetic gas ₂can be 100 volume % or lower with the total volume percent of CO, as 95 volume % or lower or 90 volume % or lower.

Reformable fuel: reformable fuel is defined as containing reformable generation H ₂the fuel of C-H.Hydrocarbon is the example of reformable fuel, and other hydrocarbon matter compound, as alcohol is also.Although CO and H ₂o can participate in water gas shift reaction to form hydrogen, and CO is not regarded as the reformable fuel under this definition.

Reformable hydrogen richness: the reformable hydrogen richness of fuel is defined as can then ordering about water gas shift reaction completely to make H by fuel by this fuel of reforming ₂generate and maximize and the H of formation ₂molecule number.Point out, H ₂there is the reformable hydrogen richness of 1, although H by definition ₂itself be not defined as reformable fuel herein.Similarly, CO has the reformable hydrogen richness of 1.Although CO is not reformable strictly, orders about water gas shift reaction and CO can be caused completely to be exchanged into H ₂.As the example of the reformable hydrogen richness of reformable fuel, the reformable hydrogen richness of methane is 4 H ₂molecule, and the reformable hydrogen richness of ethane is 7 H ₂molecule.More briefly, if fuel consist of CxHyOz, then this fuel 100% reform and water-gas shift under reformable hydrogen richness be n (H ₂maximum reformation)=2x+y/2 – z.Based on this definition, the fuel availability in battery can be expressed as n (H thereupon ₂ox)/n (H ₂maximum reformation).Certainly, can based on the reformable hydrogen richness of the reformable hydrogen richness determination component mixture of each component.Also can calculate in a similar manner containing other heteroatoms, as the reformable hydrogen richness of oxygen, sulphur or nitrogen compound.

Oxidizing reaction: in this discussion, the oxidizing reaction in the anode of fuel cell be defined as be equivalent to by with CO ₃ ^2-reaction and by H ₂oxidation is to form H ₂o and CO ₂reaction.Point out, do not comprise the reforming reaction in anode in this definition of oxidizing reaction in the anode, the compound containing C-H in reforming reaction is converted to H ₂with CO or CO ₂.Water gas shift reaction is similarly outside this definition of oxidizing reaction.Point out further, mentioning that combustion reactions is defined is mention H ₂or containing the compound of C-H at non-electrochemical burner, as in the combustion zone of burning energy supply generator with O ₂reaction forms H ₂the reaction of O and oxycarbide.

The adjustable anode fuel parameter in aspect of the present invention is to realize operating range needed for fuel cell.Anode fuel parameter can directly and/or with other fuel cell process relatively, characterize with the form of one or more ratios.Such as, anode fuel parameter can be controlled to realize one or more ratios, comprise fuel availability, fuel cell utilization rate of heat value, fuel excess rate, reformable fuel excess rate, reformable hydrogen content fuel ratio and combination thereof.

Fuel availability: fuel availability is the option run for characterizing anode, its fuel quantity based on the oxidation of the reformable hydrogen richness relative to input stream can be used for the fuel availability determining fuel cell.In this discussion, " fuel availability " is defined as being the hydrogen amount (as mentioned above) be oxidized in the anode for generating inputs the reformable hydrogen richness of (comprising any relevant reforming sections) ratio to anode.Reformable hydrogen richness has been defined as above and can have then ordered about water gas shift reaction completely to make H by fuel by this fuel of reforming ₂generate and maximize and the H of formation ₂molecule number.Such as, anode is introduced and each methane under being exposed to steam reforming conditions causes generating 4H under maximum production ₂molecular equivalency.(depend on reformation and/or anode condition, reformate can be equivalent to non-water-gas shift product, wherein one or more H ₂molecule instead exists with the form of CO molecule).Therefore, methane is defined as 4 H ₂the reformable hydrogen richness of molecule.As another example, under this definition, ethane has 7 H ₂the reformable hydrogen richness of molecule.

Fuel availability in anode also can by based on the low heat value of hydrogen be oxidized in the anode due to anode of fuel cell reaction to be sent to anode and/or the ratio of the low heat value of all fuel of the reforming sections relevant with anode defines utilization rate of heat value to characterize.The flow velocity of the fuel element entering and leave anode of fuel cell and low heat value (LHV) can be used to calculate " fuel cell utilization rate of heat value " used herein.Therefore, fuel cell utilization rate of heat value can be used as, and (LHV (anode_in) – LHV (anode_out))/LHV (anode_in) calculates, and wherein LHV (anode_in) and LHV (anode_out) refers to that anode inlet and fuel element in outlet stream or stream are (as H respectively ₂, CH ₄and/or CO) LHV.In this definition, can be used as input and/or export the numerical value summation calculating stream of each fuel element in stream or the LHV of stream.The flow velocity (such as mol/hr) that the share of each fuel element in this summation can be equivalent to fuel element is multiplied by the LHV (such as joule/mole) of fuel element.

Low heat value: low heat value is defined as fuel element and burns into gas phase complete oxidation product (i.e. gas phase CO ₂and H ₂o product) enthalpy.Such as, any CO existed in anode input stream ₂do not form the fuel content of anode input, because CO ₂complete oxidation.For this definition, the amount of oxidation occurred in the anode due to anode fuel cell reaction is defined as the H in the anode of a part for the electrochemical reaction in anode as defined above ₂oxidation.

Pointing out, is H for the sole fuel in anode inlet flow ₂special Circumstances, the generable unique reaction relating to fuel element is H in the anode ₂change into H ₂o.In this Special Circumstances, fuel availability is simplified to (H ₂-speed-enter-H ₂-speed-go out)/H ₂-speed-enter.In this case, H ₂unique fuel element, therefore H ₂lHV can cancellation from this equation.When more common, anode feed may contain the CH of such as various amount ₄, H ₂and CO.Because these thing classes can different amount be present in anode export usually, summation as mentioned above may be needed to measure fuel availability.

As substituting or supplementing fuel availability, the utilization ratio of other reactant in fuel cell can be characterized.Such as, in addition or or, can just " CO ₂utilization ratio " and/or " oxygenant " utilization ratio characterize the operation of fuel cell.CO can be specified in a similar manner ₂the value of utilization ratio and/or oxidant utilization.

Fuel excess rate: the another way characterizing the reaction in molten carbonate fuel cell is by defining utilization ratio based on the low heat value of all fuel being sent to anode and/or the reforming sections relevant to anode with the ratio of the low heat value of the hydrogen be oxidized in the anode because anode of fuel cell reacts.This amount is referred to as fuel excess rate.Therefore, fuel excess rate can be used as, and (LHV (anode_in)/(LHV (anode_in)-LHV (anode_out)) calculates, and wherein LHV (anode_in) and LHV (anode_out) refers to that anode inlet and fuel element in outlet stream or stream are (as H respectively ₂, CH ₄and/or CO) LHV.Of the present invention various in, molten carbonate fuel cell can be run to have at least about 1.0, as at least about 1.5, or at least about 2.0, or at least about 2.5, or at least about 3.0, or the fuel excess rate of at least about 4.0.In addition or or, fuel excess rate can be about 25.0 or lower.

Point out, all reformable fuel not in anode input stream all can be reformed.Preferably, enter in the input stream of anode (and/or entering relevant reforming sections) at least about 90% reformable fuel reformable before leaving anode, as at least about 95% or at least about 98%.In in other, the reformation amount of reformable fuel can be about 75% to about 90%, as at least about 80%.

The above-mentioned definition of fuel excess rate is provided to a kind of method of the amount being characterized in the reformation occurred in anode and/or the reforming sections relevant to fuel cell relative to the consumed fuel quantity that generates electricity in anode of fuel cell.

Optionally, fuel excess rate can be changed and export to take into account fuel the situation being recycled to anode input from anode.When fuel is (as H ₂, CO and/or do not reform or the hydrocarbon of partial conversion) from anode export be recycled to anode input time, the fuel that such recycled fuel component does not represent the reformable of the excess quantity that can be used for other purposes or reforms.On the contrary, such recycled fuel component only indicates the demand of the fuel availability reduced in fuel cell.

Reformable fuel excess rate: calculating reformable fuel excess rate is the option taking into account such recycled fuel component, the definition of excess fuel of its constriction, only to comprise the LHV of reformable fuel in anode input stream." reformable fuel excess rate " used herein is defined as the low heat value of the reformable fuel being sent to anode and/or the reforming sections relevant to anode and the relative value of the low heat value of the hydrogen be oxidized in the anode because anode of fuel cell reacts.Under the definition of reformable fuel excess rate, do not comprise any H in anode feed ₂or the LHV of CO.This LHV of reformable fuel still measures by characterizing the actual composition entering anode of fuel cell, does not therefore need to distinguish recyclable component and fresh components.Although some are not reformed or partial conversion fuel also can recirculation, the most of fuel being recycled to anode in most of can be equivalent to reformate, as H ₂or CO.Express with mathematical way, reformable fuel excess rate (R _rFS)=LHV _rF/ LHV _oH, wherein LHV _rFbe the low heat value (LHV) of reformable fuel and LHV _oHit is the low heat value (LHV) of the hydrogen be oxidized in the anode.LHV (such as, LHV (anode_in)-LHV (anode_out)) by deducting anode export stream in the LHV from anode inlet stream calculates the LHV of the hydrogen be oxidized in the anode.Of the present invention various in, molten carbonate fuel cell can be run to have at least about 0.25, as at least about 0.5, or at least about 1.0, or at least about 1.5, or at least about 2.0, or at least about 2.5, or at least about 3.0, or the reformable fuel excess rate of at least about 4.0.In addition or or, reformable fuel excess rate can be about 25.0 or lower.Point out, the fuel cell operation method of two types with low fuel utilization ratio can be distinguished based on this narrower definition being sent to the reformable fuel quantity of anode relative to the amount of oxidation in anode.Some fuel cells realize low fuel utilization ratio by the anode output recirculation of quite a few being returned anode input.Any hydrogen during this recirculation can make anode input is used as the input of anode again.This can reduce reformation amount, even if because low through the fuel availability of fuel cell in one way, fuel non-at least partially also recirculation is used for flow process after a while.Therefore, the fuel cell with diversified fuel utilization value can have the ratio of the identical reformable fuel being sent to anode reforming sections and the hydrogen be oxidized in anodic reaction.In order to change be sent to anode reforming sections reformable fuel and anode in the ratio of amount of oxidation, need to identify there is original content can not the anode feed of fuel reforming, or need to take out anode export in do not use fuel for other purposes, or both.

Reformable hydrogen excess rate: for characterizing another option of fuel cell operation based on " reformable hydrogen excess rate ".Reformable fuel excess rate defined above defines based on the low heat value of reformable fuel element.Reformable hydrogen excess rate is defined as the reformable hydrogen richness of the reformable fuel being sent to anode and/or the reforming sections relevant to anode and the ratio of the hydrogen reacted in the anode because anode of fuel cell reacts.Therefore, " reformable hydrogen excess rate " can be used as, and (RFC (reformable_anode_in)/(RFC (reformable_anode_in)-RFC (anode_out)) calculates, wherein RFC (reformable_anode_in) refers to the reformable hydrogen richness of the reformable fuel in anode inlet stream or stream, and RFC (anode_out) refers to that anode inlet and outlet stream or the fuel element in flowing are (as H ₂, CH ₄and/or CO) reformable hydrogen richness.RFC can with mole/second, mol/hr or similar unit representation.Under the large ratio of the amount of oxidation in the reformable fuel being sent to anode reforming sections and anode, an example of the method for fuel cell operation can be carry out the method that excess reformer occurs with the heat in balancing fuel cell and consume.Reformable fuel reforming is formed H ₂an endothermic process with CO.This thermo-negative reaction of antagonism is generated by the electric current in fuel cell, described electric current generates also can produce excessive heat, and its (roughly) corresponds to the difference of the heat generated by anodic oxidation reactions and carbonate forming reactions and the energy leaving fuel cell as an electrical current.The excessive heat of the every moles of hydrogen related in anodic oxidation reactions/carbonate forming reactions can be greater than the heat absorbed by reformation generation 1 moles of hydrogen.Therefore, the fuel cell run under conventional conditions can show intensification from the inlet to the outlet.Replace such tradition to run, the fuel quantity reformed in the reforming sections relevant to anode can be improved.Such as, extra fuel can be reformed so that heat (roughly) the balance exothermic fuel cell by consuming in reformation reacts the heat generated, or the heat of consumption of reforming even can exceed the excessive heat of oxidized generation, so that the temperature striding across fuel cell declines.This can cause generating with electric power needed for amount compared with hydrogen significantly excessive.As an example, the charging sending into the anode inlet of fuel cell or relevant reforming sections can substantially by reformable fuel, as substantially pure methane feed formation.In the traditional operational process using this fuel power generation function, molten carbonate fuel cell can be run with the fuel availability of about 75%.This means that about 75% (or 3/4) of the fuel content being sent to anode is for the formation of hydrogen, it reacts with carbanion in the anode subsequently and forms H ₂o and CO ₂.In conventional operation, the fuel content remaining about 25% can be reformatted into H in fuel cell ₂(or can for any CO or H in fuel ₂pass fuel cell unreacted), then burn outward to form H at fuel cell ₂o and CO ₂with the cathode inlet heat supply to fuel cell.Reformable hydrogen excess rate can be 4/ (4-1)=4/3 in this case.

Electrical efficiency: term used herein " electrical efficiency " (" EE ") is defined as low heat value (" the LHV ") rate that the electrochemical kinetics that produced by fuel cell inputs divided by the fuel of fuel cell.The fuel input of fuel cell comprises the fuel that is sent to anode and for keeping any fuel of the temperature of fuel cell, as being sent to the fuel of the burner relevant to fuel cell.In this manual, the power produced by this fuel can describe with LHV (el) fuel rate (fuelrate).

Electrochemical kinetics: term used herein " electrochemical kinetics " or LHV (el) are circuit by connecting negative electrode and positive electrode in fuel cell and carbanion through the transfer of fuel-cell electrolyte and the power generated.The power that the equipment that electrochemical kinetics does not comprise fuel cell upstream or downstream produces or consumes.Such as, a part for electrochemical kinetics is not regarded as by the thermogenetic electricity in fuel cell exhaust stream.Similarly, the power generated by internal combustion turbine or the miscellaneous equipment of fuel cell upstream is not a part for the electrochemical kinetics generated." electrochemical kinetics " does not consider the electric power consumed in fuel cell operation or any loss becoming alternating-current to cause by DC conversion.In other words, from the direct current power that fuel cell produces, do not deduct the electric power for supplying fuel cell operation or otherwise fuel cell operation.Power density used herein is that current density is multiplied by voltage.Total fuel battery power used herein is that power density is multiplied by fuel cell area.

Fuel inputs: term used herein " anode fuel input ", being referred to as LHV (anode_in), is the fuel quantity in anode inlet stream.Term " fuel input ", being referred to as LHV (in), is the total amount of fuel being sent to fuel cell, comprises fuel quantity in anode inlet stream and for keeping the fuel quantity of the temperature of fuel cell.Based on the definition of reformable fuel provided herein, this fuel can comprise reformable and not reformable fuel.Fuel input is different from fuel availability.

Total fuel cell efficiency: term used herein " total fuel cell efficiency " (" TFCE ") is defined as: the electrochemical kinetics generated by fuel cell adds the speed (rateofLHV) of the LHV of the synthetic gas generated by fuel cell, the speed of the LHV that the fuel divided by anode inputs.In other words, TFCE=(LHV (el)+LHV (sgnet))/LHV (anode_in), wherein LHV (anode_in) refers to that the fuel element being sent to anode is (as H ₂, CH ₄and/or CO) the speed of LHV, and LHV (sgnet) refers to and produces synthetic gas (H in the anode ₂, CO) speed, it is the difference that the synthetic gas input of anode exports with the synthetic gas of anode.The electrochemical kinetics that LHV (el) describes fuel cell generates.Total fuel cell efficiency is not included in the heat for the useful utilization outside this fuel cell generated by this fuel cell.Be in operation, the heat generated by fuel cell may by the useful utilization of upstream device.Such as, this heat can be used for generating extra electric power or for heating water.When using this term in this application, these purposes implemented outward at fuel cell are not parts for total fuel cell efficiency.Total fuel cell efficiency is only for fuel cell operation, and the power not comprising fuel cell upstream or downstream generates or consumes.

Chemical efficiency: term used herein " chemical efficiency " is defined as the H in the anode exhaust of fuel cell ₂with the low heat value of CO or LHV (sgout) divided by fuel input or LHV (in).

Electrical efficiency and overall system efficiency do not consider the efficiency of upstream or downstream process.Such as, can advantageously use gas turbine exhaust as the CO of fuel battery negative pole ₂source.In this arrangement, the efficiency of turbine is not regarded as a part for electrical efficiency or total fuel cell efficiency calculating.Similarly, can be used as input from the output of fuel cell and be recycled to fuel cell.Recirculation loop is not considered when calculating electrical efficiency or total fuel cell efficiency with single pass mode.

The synthetic gas generated: term used herein " synthetic gas of generation " is the difference that the synthetic gas input of anode exports with the synthetic gas of anode.Synthetic gas can be used as input or the fuel of anode at least partly.Such as, system can comprise anode recirculation loop, and it sends the synthetic gas from anode exhaust back to anode inlet, at this to its supplemental natural gas or other suitable fuel.Synthetic gas LHV (sgnet)=(LHV (the sgout)-LHV (sgin)) generated, wherein LHV (sgin) and LHV (sgout) refers to the LHV of synthetic gas in anode inlet and anode export stream or the synthetic gas in flowing respectively.Point out, the synthetic gas at least partially generated by the reforming reaction in anode usually can in the anode for generating.For the hydrogen that generates electricity not included in the definition of " synthetic gas of generation ", because it does not leave anode.Term used herein " syngas ratio " is LHV or LHV (sgnet)/LHV (anodein) that the LHV of the clean synthetic gas generated inputs divided by the fuel of anode.Mole flow velocity of synthetic gas and fuel can be used to replace LHV to represent the synthetic gas of the generation of mole base syngas ratio and mole base.

Vapor carbon ratio (S/C): vapor carbon ratio used herein (S/C) is the mol ratio of the steam in stream and the reformable carbon in stream.CO and CO ₂the carbon of form does not count the reformable carbon in this definition.Can measure and/or control vapor carbon ratio by difference within the system.Such as, the composition of anode inlet stream can be controlled to realize the S/C of the reformation in applicable anode.S/C can as H ₂mole flow velocity of O provides divided by (mole flow velocity of fuel is multiplied by the product of the carbonatoms (such as methane is 1) in fuel).Therefore, S/C=f _h20/ (f _cH4x#C), wherein f _h20mole flow velocity of water, wherein f _cH4be mole flow velocity of methane (or other fuel) and #C is the carbon number in fuel.

EGR compares: each aspect of the present invention can use the turbine cooperated with fuel cell.Comprehensive fuel battery and turbine system can comprise exhaust gas recirculatioon (" EGR ").In egr system, the exhaust at least partially that turbine generates can be sent to recovery of heat producer.Another part exhaust can be sent to fuel cell.EGR is sent to total exhaust of fuel cell or recovery of heat producer than describing the free air delivery vs being sent to fuel cell." EGR than " used herein is that the flow velocity of the fuel cell relevant portion of exhaust is divided by fuel cell relevant portion and the overall flow rate of recovery relevant portion being sent to recovery of heat producer.

Of the present invention various in, molten carbonate fuel cell (MCFC) can be used for promoting from containing CO ₂separation of C O in stream ₂, also generate extra electric power simultaneously.Can utilize and strengthen CO further with the synergy of combustion radicals generator (it can provide to the cathode portion of fuel cell and input charging at least partially) ₂be separated.

Fuel cell and fuel cell component: in this discussion, fuel cell can be equivalent to monocell, and its Anodic and negative electrode are separated by an electrolyte.Anode and negative electrode can receive input air-flow to promote respective anode and cathodic reaction, transferring charge crossed ionogen and to generate electricity.Fuel cell pack can represent the multiple batteries in integrated unit.Although fuel cell pack can comprise multiple fuel cell, fuel cell usually can be in parallel and can (roughly) show represent the larger single fuel cell of size as their collectives.When carrying inlet flow to the male or female of fuel cell pack, this fuel assembly can comprise for distributing the flow passage of inlet flow and the flow passage for merging the output stream from each battery between each battery in this heap.In this discussion, fuel cell array can be used for representing series, parallel or (combination of such as series and parallel connections) multiple fuel cells (as multiple fuel cell pack) of arranging in any other convenient way.Fuel cell array can comprise one or more sections of fuel cell and/or fuel cell pack, and the anode/cathode wherein from first paragraph exports the anode/cathode input can serving as second segment.Point out, the anode in fuel cell array need not connect in the mode identical with the negative electrode in this array.For simplicity, the input of the first anode section of fuel cell array can be referred to as the anode input of this array, and the input of the first negative electrode section of fuel cell array can be referred to as the negative electrode input of this array.Similarly, the output of final anode/cathode section can be referred to as the anode/cathode output of this array.

It should be understood that to mention in this article uses fuel cell to typically refer to " fuel cell pack " that be made up of multiple single fuel cell, more generally refers to the one or more fuel cell packs using fluid to be communicated with.Usually by independent fuel cell component (plate) together with rectangular array " stacking ", can be referred to as " fuel cell pack ".This fuel cell pack can obtain incoming flow and usually by reactant distribution between all independent fuel cell components, then can from each component collection product.When being regarded as a unit, fuel cell pack is in operation and can be taken as entirety, although be made up of many (usually tens of or hundreds of) independent fuel cell component.These independent fuel cell components can have similar voltage (because reactant similar to production concentration) usually, and when these elements electricity series connection, total electricity exports can from the summation of all electric currents in all cell devices.Battery pile also can arranged in series to produce high-voltage.Being arranged in parallel can motor current.If the fuel cell pack of enough large volumes can be provided to process given exhaust stream, system and method described herein can pile with single molten carbonate fuel cell together with use.Of the present invention in other in, because many reasons may desirable or it is desirable that multiple fuel cell pack.

For the purpose of the present invention, unless specifically stated so, term " fuel cell " should be understood to also refer to and/or be defined as to comprise the fuel cell pack be made up of the combination of one or more independent fuel cell component relating to and have single input and output, because this is fuel cell usual use-pattern in practice.Similarly, unless specifically stated so, term fuel cell (plural number) should be understood to also refer to and/or be defined as to comprise multiple independently fuel cell pack.In other words, unless stated otherwise, all the mentioning in this paper refers to that fuel cell pack runs as " fuel cell " interchangeably.Such as, the exhaust volume that commercial-scale burning generators generates may consequently cannot be processed by the fuel cell of stock size (i.e. cell stack) too greatly.In order to process whole exhaust, multiple fuel cell (i.e. two or more independently fuel cell or fuel cell pack) can be arranged in parallel, with the burning and gas-exhausting making each fuel cell can process (roughly) moiety.Although can use multiple fuel cell, consider the burning and gas-exhausting of its (roughly) moiety, each fuel cell can run usually in a substantially similar manner.

" inside reforming " and " outside reformation ": fuel cell or fuel cell pack can comprise one or more inside reforming section.Term used herein " inside reforming " refers in the main body of fuel cell, fuel cell pack or the fuel reforming otherwise occurred in fuel cell module.Usually and the outside of fuel cell conbined usage reform and to carry out being arranged in the independent means part outside fuel cell pack.In other words, the main body of external reformer does not contact with the main body direct physical of fuel cell or fuel cell pack.In typical layout, the output from external reformer can be sent into the anode inlet of fuel cell.Except non-specifically illustrates separately, the reformation described in the application is inside reforming.

Inside reforming can carry out in anode of fuel cell.In addition or or, inside reforming can carry out being integrated in the inside reforming element in fuel cell module.Integrated reforming element can between the fuel cell component in fuel cell pack.In other words, one of plate in battery pile can be reforming sections but not fuel cell component.On the one hand, fuel leads inside reforming element by the flow arrangement in fuel cell pack, then imports the anode part of fuel cell.Therefore, from flowing angle, inside reforming element and fuel cell component can be disposed in series in fuel cell pack.Term used herein " anode reformation " is the fuel reforming occurred in anode.Term used herein " inside reforming " is the reformation occurred in integrated reforming element but not in anode segment.

In certain aspects, the reforming sections in fuel cell module can be considered to relevant to the anode in fuel cell module.In in other, for can reforming sections in the fuel cell pack of relevant to anode (as being correlated with multiple anode), the flowing-path output stream from reforming sections being sent at least one anode can be provided.This can be equivalent to have fuel cell plate initial segment, and this Duan Buyu ionogen contacts but only can serve as reforming catalyst.Another option of relevant reforming sections can be have independent integrated reforming sections as one of element in fuel cell pack, wherein the output from integrated reforming sections can be sent back to the input side of the one or more fuel cells in fuel cell pack.

From hot integrated angle, the feature height in fuel cell pack can be the height of independent fuel cell Nuclear fuel.Point out, independently reforming sections and/or independently thermo-negative reaction section can have the height different from fuel cell in this heap.In this case, the height of fuel cell component can be used as feature height.In certain aspects, integrated thermo-negative reaction section can be defined as the section integrated with one or more fuel cell heat, can utilize with the thermo-negative reaction section making this integrated the thermal source that the hotwork from fuel cell is thermo-negative reaction.This integrated thermo-negative reaction section can be defined as being less than with any fuel cell to this integrated section of heat supply 5 times of a Nuclear fuel height apart and locate.Such as, any fuel cell that integrated thermo-negative reaction section (as reforming sections) can be integrated with heat is less than 5 times of a Nuclear fuel height apart, as being less than 3 times of places of a Nuclear fuel height.In this discussion, the integrated reforming sections and/or the integrated thermo-negative reaction section that represent the adjacent Nuclear fuel of fuel cell component can be defined as with adjacent fuel cell element at a distance of an about Nuclear fuel height or less.

In certain aspects, integrated to fuel cell component heat independent reforming sections can be equivalent to the reforming sections relevant with fuel cell component.In in such, integrated fuel cell component can provide heat at least partially to relevant reforming sections, and reforming sections at least partially can export and is supplied to integrated fuel cell as fuel streams by relevant reforming sections.In in other, independent reforming sections can be integrated to conduct heat with fuel cell, but not relevant to fuel cell.In such situation, this independent reforming sections can receive heat from fuel cell, but can determine the input output of reforming sections not being used as fuel cell.On the contrary, the output of this reforming sections can be determined to be used for another purposes, as this output directly added in anode exhaust stream and/or the independent output stream formed from fuel cell module.

More generally, the independent Nuclear fuel in fuel cell pack can be used to carry out any thermo-negative reaction facilitating type of the used heat that integrated fuel cell Nuclear fuel can be utilized to provide.Replace being applicable to plate hydrocarbon fuel stream being carried out to reforming reaction, independent Nuclear fuel can have the plate of the thermo-negative reaction being applicable to catalysis another type.Other layout of manifold or inlet conduits can be used in a fuel cell stack to provide suitable inlet flow to each Nuclear fuel.Other layout of similar manifold or delivery channel can additionally or alternatively for taking out output stream from each Nuclear fuel.Optionally, the output stream of the thermo-negative reaction section in heap can be taken out from fuel cell pack and not make this output stream through anode of fuel cell.So optional in, the product of thermopositive reaction therefore can when leaving fuel cell pack without when anode of fuel cell.The example of the thermo-negative reaction of other type can carried out in Nuclear fuel in a fuel cell stack can include but not limited to that ethanol dehydration forms ethene, and ethane cracking.

Recirculation: as defined herein, a part of fuel cell exports, and (as anode exhaust or the stream that is separated from anode exhaust or takes out) is recycled to fuel cell inlet, and this can be equivalent to direct or indirect recycle stream.Stream is directly recycled to the stream recirculation that fuel cell inlet is defined as without pilot process, and indirect recycling relates to and makes the recirculation of stream after one or more pilot process.Such as, if anode exhaust is before being recycled through CO ₂segregation section, this is regarded as the indirect recycling of anode exhaust.If by a part for anode exhaust, as the H taken out from anode exhaust ₂stream is sent into and is used for coal being changed into the gasifier being applicable to the fuel introducing fuel cell, and this is also regarded as indirect recycling.

anode input and output

Of the present invention various in, can feed to MCFC array the fuel received in anode inlet, it comprises such as hydrogen and hydrocarbon, as methane (or, may containing heteroatomic hydrocarbon matter or the class hydrocarbon compound being different from C and H).The most of methane (or other hydrocarbon matter or class hydrocarbon compound) sending into anode can be fresh methane usually.In this manual, fresh fuel is not the fuel come from another fuel cell process recirculation as fresh methane refers to.Such as, the methane being recycled to anode inlet from anode export stream can not be regarded as " fresh " methane, but can be described to regenerate methane.Fuel used source can be shared with other parts, and as turbine, turbine utilizes a part of fuel source to provide containing CO to negative electrode input ₂stream.The input of this fuel source can comprise the water proportional with this fuel, and described ratio is suitable for reforming hydrocarbon in reforming sections (or class hydrocarbon) compound and generates hydrogen.Such as, if methane is for reforming to generate H ₂fuel input, water can be about 1 to 1 to about 10 to 1 with the mol ratio of fuel, as at least about 2 to 1.It is typical that the ratio of 4 to 1 or larger is reformed to outside, but lower value may be typical to inside reforming.At H ₂in degree as a part for fuel source, in some are optional, extra water may not be needed in fuel, because the H at anode place ₂oxidation can be tended to produce and to be can be used for reforming the H of this fuel ₂o.Fuel source also optionally can contain the subsidiary component of this fuel source, and (such as, natural gas feed can contain the CO of certain content ₂as annexing ingredient).Such as, natural gas feed can contain CO ₂, N ₂and/or other inertia (rare) gas is as annexing ingredient.Optionally, in certain aspects, this fuel source also can contain CO, as the CO of the recycling part from anode exhaust.Entering the additional of the CO in the fuel of fuel cell module or may originating of substituting can be the CO generated by the hydrocarbon fuel steam reformation carried out fuel before entering fuel cell module.

More generally, various types of fuel streams can be suitable as the input stream of the anode of molten carbonate fuel cell.Some fuel streams can be equivalent to containing hydrocarbon and/or the stream that also can comprise the heteroatomic class hydrocarbon compound being different from C and H.In this discussion, unless specifically stated so, the mentioning of hydrocarbon containing fuels stream for MCFC anode is defined as comprising the fuel streams containing such class hydrocarbon compound.The example of hydrocarbon (comprising class hydrocarbon) fuel streams comprises Sweet natural gas, containing the stream of C1-C4 carbon compound (as methane or ethane) and the stream containing heavier C5+ hydrocarbon (comprising class hydrocarbon compound) and their combination.Other examples that are additional or that substitute for the possible fuel streams in anode input can comprise the stream of biogas type, as decomposed by natural (biology) of organic materials the methane produced.

In certain aspects, molten carbonate fuel cell can be used for processing the input fuel streams owing to there is thinner compound with low energy content, as Sweet natural gas and/or hydrocarbon stream.Such as, some sources of methane and/or Sweet natural gas are the CO that can comprise significant quantity ₂or other inert molecule, as the source of nitrogen, argon or helium.Owing to there is the CO of increasing amount ₂and/or inert material, the energy content of the fuel streams based on this source can be reduced.The fuel of low energy content is used for combustion reactions (as the turbine energy supply for energy supply of burning) and can causes difficulty.But molten carbonate fuel cell can generate electricity based on the fuel source of low energy content and have reduction or minimum impact to the efficiency of fuel cell.The existence of additional gas volume can need the heat of adding to be risen to by fuel temperature for reforming and/or the temperature of anodic reaction.In addition, due to the equilibrium property of the water gas shift reaction in anode of fuel cell, additional CO ₂existence can affect anode export in exist H ₂with the relative quantity of CO.But in addition, inert compound only can have minimum direct impact to reformation and anodic reaction.CO in the fuel streams of molten carbonate fuel cell ₂and/or the amount of inert compound (when it is present) can be at least about 1 volume %, as at least about 2 volume %, or at least about 5 volume %, or at least about 10 volume %, or at least about 15 volume %, or at least about 20 volume %, or at least about 25 volume %, or at least about 30 volume %, or at least about 35 volume %, or at least about 40 volume %, or at least about 45 volume %, or at least about 50 volume %, or at least about 75 volume %.In addition or or, CO in the fuel streams of molten carbonate fuel cell ₂and/or the amount of inert compound can be about 90 volume % or lower, as about 75 volume % or lower, or about 60 volume % or lower, or about 50 volume % or lower, or about 40 volume % or lower, or about 35 volume % or lower.

Other examples that may originate of anode input stream can be equivalent to the output stream of oil refining and/or other industrial technology.Such as, coking is for heavy compounds being changed into the common technology of lower boiling range in many refinerys.Coking produces usually containing being at room temperature the multiple compounds of gas, comprises the waste gas of CO and various C1-C4 hydrocarbon.This waste gas can be used as anode input stream at least partially.In addition or or, other refinery flares streams can be applicable to being included in anode input stream, as the lighting end (C1-C4) generated in cracking or other refinery processes process.In addition or or, other suitable refinery streams can comprise containing CO or CO ₂refinery stream, it is also containing H ₂and/or reformable fuel compound.

In addition or or, other possible sources of anode input can comprise the stream of the water-content with raising.Such as, export from the ethanol of ethanol factory (or zymotechnique of another type) H that stream can comprise quite a few before final distillation ₂o.Such H ₂o can only cause minimum impact to the operation of fuel cell usually.Therefore, the fermenting mixture of alcohol (or other tunning) and water can be used as anode input stream at least partially.

Biogas or biogas are another additional or substitute may originating of anode input.Biogas may mainly comprise methane and CO ₂and usually produced by organic decomposition or digestion.Anerobe can be used for digestion of organic matter and produces biogas.Impurity can be removed from biogas, as sulfocompound before being used as anode input.

Output stream from MCFC anode can comprise H ₂o, CO ₂, CO and H ₂.Optionally, this anode exports stream and also can have unreacted fuel in charging (as H ₂or CH ₄) or inert compound as additional output component.Replacing using this output stream as the fuel source to reforming reaction heat supply or as being used for the combustion fuel of heating battery, stream can be exported carry out one or many separation with by CO by antianode ₂with the component with the potential value inputted as another technique, as H ₂or CO is separated.H ₂and/or CO can be used as chemosynthesis synthetic gas, be used as chemical reaction hydrogen source and/or as the fuel of greenhouse gas emission with reduction.

In in various, the composition of the output stream of anode can affect by some questions.The factor that can affect anode output composition can comprise the temperature of the composition of the input stream of anode, the magnitude of current generated by fuel cell and/or anode export.Due to the equilibrium property of water gas shift reaction, the temperature of anode export can be related.In typical anode, at least one plate forming anode wall is applicable to catalytic water shift conversion reaction.Therefore, if a) composition of anode input stream is known, the reformation degree of the reformable fuel b) in anode input stream is known, with the amount of carbonate c) from cathode transport to anode (corresponding to the magnitude of current generated) is known, then the composition that can export based on the equilibrium constant determination anode of water gas shift reaction.

K _eq＝[CO ₂][H ₂]/[CO][H ₂O]

In above-mentioned equation, K _eqbe the equilibrium constant of this reaction under given temperature and pressure, and [X] is the dividing potential drop of component X.Based on water gas shift reaction, can point out, the CO improved in anode input ₂concentration can be tended to cause extra CO to be formed (with H ₂for cost), and the H improved ₂o concentration can be tended to cause extra H ₂formed (taking CO as cost).

In order to measure the composition that anode exports, composition that anode inputs can be used as starting point.Then this composition can be changed to be reflected in the reformation degree of contingent any reformable fuel in anode.This reformation can reduce the hydrocarbon content of anode input, is transformed into hydrogen and the CO of increase ₂.Then, based on the magnitude of current generated, the H in anode input can be reduced ₂amount, is transformed into extra H ₂o and CO ₂.Then this composition can be regulated to measure H based on the equilibrium constant of water gas shift reaction ₂, CO, CO ₂and H ₂the exit concentration of O.

Table 1 shows the anode exhaust composition of fuel under different fuel utilization ratio for typical types.Anode exhaust composition can reflect the synthesis result of anode reforming reaction, water gas shift reaction and anodic oxidation reactions.Output composition value in table 1 has the vapour (H of about 2 to 1 by hypothesis anode input composition ₂o)/carbon (reformable fuel) compares and calculates.Suppose that reformable fuel is methane, suppose that it 100% is reformatted into hydrogen.Suppose the initial CO in anode input ₂and H ₂concentration can be ignored, and inputs N ₂concentration is about 0.5%.Fuel availability U is made as shown in this table _f(as defined herein) changes from about 35% to about 70%.In order to measure the exact value of the equilibrium constant, suppose that the temperature out of anode of fuel cell is about 650 DEG C.

Table 1-anode exhaust composition

What table 1 was presented at condition and anode input composition specificly arranges lower anode and exports and form.More generally, in various, anode exports and can comprise about 10 volume % to about 50 volume %H ₂o.H ₂the amount of O can change to a great extent, because the H in anode ₂o can be produced by anodic oxidation reactions.If will the excessive H of reformation aequum be exceeded ₂o introduces anode, then except the H due to fuel reforming and water gas shift reaction consumption (or generation) ₂outside O, this excessive H ₂o can pass through usually mostly unreacted.CO during anode exports ₂concentration also can change to a great extent, as about 20 volume % to about 50 volume %CO ₂.Generate the magnitude of current and anode inlet flow in CO ₂amount all can affect CO ₂amount.In addition or or, depend on the fuel availability in anode, anode export in H ₂amount can be about 10 volume %H ₂to about 50 volume %H ₂.In anode exports, CO amount can be about 5 volume % to about 20 volume %.Point out, for given fuel cell, anode export in relative to H ₂the CO amount measured can depend in part on the equilibrium constant of the water gas shift reaction under the temperature and pressure existed in a fuel cell.In addition or or, anode export also can comprise 5 volume % or less other components various, as N ₂, CH ₄(or other unreacted carbonaceous fuel) and/or other component.

Optionally, if need, can anode export after comprise one or more water gas shift reaction section with by anode export in CO and H ₂o changes into CO ₂and H ₂.Can such as by a lower temperature use water-gas shift will anode export in exist H ₂o and CO changes into H ₂and CO ₂improve during anode exports the H existed ₂amount.Or, temperature can water gas shift reaction be reversed can be improved, with by H ₂and CO ₂produce more CO and H ₂o.Water is that the expection of the reaction occurred at anode place exports, therefore this anode export usually can have export with anode in the CO that exists measure compared with excessive H ₂o.Or, can after anode export but by H before water gas shift reaction ₂o adds in stream.Due to the incomplete carbon in reforming process transform and/or due to the condition of reorganization or in anodic reaction process H under existent condition ₂o, CO, H ₂and CO ₂between balanced reaction (i.e. water gas shift equilibrium), anode export in can there is CO.Water-gas shift can with CO and H ₂o is that cost is further towards formation CO ₂and H ₂direction drive the condition of this balance under run.Comparatively high temps is often conducive to forming CO and H ₂o.Therefore, running an option of water-gas shift can be in suitable temperature, such as, makes anode output stream be exposed to suitable catalyzer at about 190 DEG C to about 210 DEG C, as comprise ferric oxide, zinc oxide, copper/zinc oxide etc. catalyzer under.This water-gas shift optionally can comprise two sections exporting the CO concentration in stream for reducing anode, wherein the first higher temperatures section is run at the temperature of at least about 300 DEG C to about 375 DEG C, second comparatively low-temperature zone at about 225 DEG C or lower, as run at the temperature of about 180 DEG C to about 210 DEG C.Except improving during anode exports the H existed ₂outside amount, in addition or or, water gas shift reaction can be that cost improves CO with CO ₂amount.The carbon monoxide (CO) that difficulty removes can be transformed into carbonic acid gas by this, and carbonic acid gas passes more readily condensation (such as deep cooling removes), chemical reaction (as amine removal) and/or other CO ₂removal method removes.In addition or or, may desirably improve in anode exhaust the CO content that exists to realize required H ₂/ CO ratio.

After optional water gas shift reaction section, anode can be made to export through one or more segregation section to export in stream except anhydrating and/or CO from anode ₂.Such as, by independence or combinationally use one or more method antianodes export carry out CO ₂be separated and form one or more CO ₂export stream.These methods can be used for generation and have 90 volume % or higher, as at least 95% volume %CO ₂or at least 98 volume %CO ₂cO ₂the CO of content ₂export stream.The CO that the recyclable anode of these methods exports ₂about at least 70% of content, as the CO that anode exports ₂at least about 80% of content, or at least about 90%.Or, in certain aspects may desirably reclaim the only a part of CO in anode output stream ₂, the CO of recovery ₂part is the CO in anode output ₂about 33% to about 90%, as at least about 40%, or at least about 50%.Such as, may desirably make some CO ₂stay in anode output stream so that required composition can be realized in water gas shift stage subsequently.Suitable separation method can comprise use physical solvent (such as, Selexol ^tMor Rectisol ^tM); Amine or other alkali (such as, MEA or MDEA); Refrigeration (such as, low temperature separation process); Pressure-variable adsorption; Vacuum Pressure Swing Adsorption; With their combination.Deep cooling CO ₂separator can be an example of suitable separator.Export cooling along with by anode, the most of water during anode exports can be used as condensation (liquid) and is separated out.Further cooling and/or the pressurization of poor-water anode output stream can be separated high-purity CO subsequently ₂, because other remaining ingredient in anode output stream is (as H ₂, N ₂, CH ₄) be not easy to form condensation phase.Depend on operational conditions, deep cooling CO ₂the CO existed in the recyclable stream of separator ₂about 33% to about 90%.

It is also useful for dewatering to form one or more water output stream material from anode exhaust, and no matter this is carrying out CO ₂before separation, among or after.The water yield during anode exports can become with selected operational conditions.Such as, the vapour/carbon ratio set up in anode inlet can affect water-content in anode exhaust, and high vapour/carbon ratio causes a large amount of water usually, its can unreacted ground by anode and/or only react due to the water gas shift equilibrium in anode.According to this aspect, the water-content in anode exhaust can be equivalent to nearly about 30% or larger of volume in anode exhaust.In addition or or, water-content can be about 80% or less of anode exhaust volume.Although by compression and/or cooling and thereupon condensation remove such water, the removing of this water can need extra compressor power and/or a large amount of water coolant of heat exchange surface sum.A kind of beneficial manner removing a part of this excessive water can based on use adsorbent bed, and it can catch moisture from wet Anode effluent, then can utilize dry anode feed gas " regeneration ", provide extra water with anode charging.HVAC-type (heating, ventilation and artificial atmosphere) sorption wheel design can be applicable, because anode exhaust and entrance can be similar on pressure, and can have minimum impact from a stream to the minor leakage of another stream to whole technique.CO is carried out in use Deep Cooling Method ₂in the embodiment removed, at CO ₂before removing or among to dewater may be desirable, comprise and being dewatered by triethylene glycol (TEG) system and/or siccative.On the contrary, if use amine eccysis to remove CO ₂, then can at CO ₂the section of removing downstream dewaters from anode exhaust.

Replace or except CO ₂export outside stream and/or water output stream, anode exports and can be used for forming one or more product stream containing required chemistry or fuel Products.Such product stream can be equivalent to both synthetic gas stream, hydrogen stream or syngas product and hydrogen gas product stream.Such as, can be formed containing at least about 70 volume %H ₂, as at least about 90 volume %H ₂or at least about 95 volume %H ₂hydrogen gas product stream.In addition or or, the H containing at least about 70 volume % altogether can be formed ₂and CO, as the H of at least about 90 volume % ₂with the synthetic gas stream of CO.Described one or more product stream can have the total H be equivalent in anode output ₂with at least about 75% of CO gas volume, as total H ₂with at least about 85% of CO gas volume or the gas volume of at least about 90%.Point out, based on utilizing water gas shift reaction section to transform between product, H in product stream ₂the H in anode output may be different from the relative quantity of CO ₂/ CO ratio.

In certain aspects, may desirably remove or be separated during anode exports a part of H existed ₂.Such as, the H in certain aspects in anode exhaust ₂/ CO ratio can be at least about 3.0:1.On the contrary, utilize the technique of synthetic gas, as F-T synthesis can with different ratio, as the ratio close to 2:1 consumes H ₂and CO.An alternatives can be utilize water gas shift reaction to change the content of anode output to have the H formed closer to required synthetic gas ₂/ CO ratio.Another alternatives can be utilize membrane sepn to remove a part of H existed in anode output ₂to realize required H ₂/ CO ratio, or the combination using membrane sepn and water gas shift reaction.Only a part of H in utilizing membrane sepn removing anode to export ₂an advantage can be can carry out required separation under relatively mild conditions.Because a target can be produce still to have remarkable H ₂the retentate of content, generates the penetrant of High Purity Hydrogen by membrane sepn and does not need exacting terms.Such as, permeate side under the pressure higher than environmental stress, still can have the motivating force being enough to carry out membrane sepn simultaneously, but not on membrane permeate side, has the pressure of about 100kPaa or lower (as environmental stress).In addition or or, sweeping gas such as methane can be used to provide the motivating force of membrane sepn.This can reduce H ₂the purity of penetrant stream, but the required purposes depending on this penetrant stream may be favourable.

Of the present invention various in, anode exhaust stream is (preferably at separation of C O at least partially ₂and/or H ₂after O) can be used as the charging of the technique outside fuel cell and relevant reforming sections.In in various, anode exhaust can have about 1.5:1 to about 10:1, as at least about 3.0:1, or at least about 4.0:1, or the H of at least about 5.0:1 ₂/ CO ratio.Can be generated by anode exhaust or take out synthetic gas stream.Anode exhaust, optionally at separation of C O ₂and/or H ₂after O and optionally carrying out water gas shift reaction and/or membrane sepn with after remove excess hydrogen, can be equivalent to contain quite a few H ₂and/or the stream of CO.For the stream with relatively low CO content, as H ₂/ CO is than the stream at least about 3:1, and this anode exhaust can be suitable as H ₂charging.H can be benefited from ₂the example of the technique of charging can include, but not limited to turbine in refinery processes, ammonia synthesizer or (difference) power generation system or its combination.According to purposes, still lower CO ₂content may be desirable.For have be less than about 2.2 to 1 and be greater than about 1.9 to 1 H ₂the stream of/CO ratio, this stream can be suitable as synthetic gas charging.The example that can benefit from the technique of synthetic gas charging can include, but not limited to gas-to-liquid plant (as used the device by the Fischer-Tropsch method of non-shifting catalyst) and/or methanol synthesizer.Amount as the anode exhaust of the charging of external process can be anyly to measure easily.Optionally, when the charging using a part of anode exhaust as external process, the anode exhaust of second section can be recycled to anode input and/or be recycled to the combustion zone of burning energy supply generator.

The input stream that can be used for dissimilar Fischer-Tropsch synthesis process can provide the example being applicable to being exported the dissimilar product stream generated by anode.For use transformation catalyst, as the Fischer-Tropsch synthesis system of ferrum-based catalyst, the required input stream of this reactive system is except H ₂also CO can be comprised outward with CO ₂.If there is not enough CO in input stream ₂, the fischer-tropsch catalysts with water-gas shift activity can consume CO to generate extra CO ₂, cause the synthetic gas of possibility CO deficiency.In order to by this Fischer-tropsch process and MCFC fuel cell integrated, segregation section that anode exports can be run with CO needed for keeping in syngas product ₂(with optional H ₂o) measure.On the contrary, to the fischer-tropsch catalysts based on non-shifting catalyst, any CO existed in product stream ₂the inert component in fischer-tropsch reaction system can be served as.

With sweeping gas, as methane sweeping gas purges in the aspect of film, methane sweeping gas can be equivalent to be used as anode fuel or for different low pressure process, as the methane stream of boiler, stove, internal combustion turbine or other fuel consumers.In this one side, stride across the low-level CO of this film ₂infiltration can have minimum consequence.This CO of film may be penetrated ₂reaction in antianode can have minimal effects, and this CO ₂can be retained in anodic product.Therefore, the CO of the cross-film loss due to infiltration ₂(if any) do not need to be displaced through MCFC ionogen again.This significantly can reduce the separation selectivity requirement to permeable hydrogen membrane.This can allow such as to use has lower optionally higher permeability film, and it film surface-area of use lower pressure and/or reduction can become possibility.In this one side of the present invention, the volume of sweeping gas can be the large multiple of the hydrogen volume in anode exhaust, and this can make the effective density of hydrogen in permeate side keep close to 0.The hydrogen be separated thus can be incorporated in the charging methane of turbine, can strengthen turbine combustion feature as mentioned above this its.

Point out, the excessive H generated in the anode ₂the fuel having isolated greenhouse gases can be represented.Any CO during anode exports ₂can easily be separated from anode exports, as by using, amine is washed, deep cooling CO ₂separator and/or transformation or vacuum pressure swing adsorption process.Several component (H that anode exports ₂, CO, CH ₄) be not easy removing, and CO ₂and H ₂o can easily remove usually.According to this embodiment, the CO in anode output can be isolated ₂at least about 90 volume %, form relatively high-purity CO ₂export stream.Therefore, any CO generated in the anode can effectively be isolated ₂to form high-purity CO ₂output stream.After isolation, the remainder that anode exports mainly can be equivalent to have the component of chemistry and/or fuel value and the CO of reducing amount ₂and/or H ₂o.Due to quite a few CO generated by original fuel (before reformation) ₂can be separated, the CO generated with afterfire exported by the anode of remainder can be reduced ₂amount.Especially, the fuel in the anode of remainder exports is H ₂degree on, usually can not form extra greenhouse gases by the burning of this fuel.

Antianode exhaust can impose the processing of various gas and select, comprise the disconnected from each other of water-gas shift and component.Two kinds of general Anode machining scheme displays in figs. 6 and 7.

Fig. 6 schematically shows an example with the reactive system of the fuel cell array of chemical synthesis process cooperation molten carbonate fuel cell.In figure 6, fuel streams 605 is provided to (or multiple) reforming sections 610 relevant to the anode 627 of fuel cell 620 (fuel cell as the part as the fuel cell pack in fuel cell array).The reforming sections 610 relevant to fuel cell 620 can in fuel cell module.In in some are optional, also can use the reformable fuel of a part that outside reforming sections (not shown) was reformed in input stream before input stream is sent into fuel cell module.Fuel streams 605 can preferably include reformable fuel, as methane, other hydrocarbon and/or other class hydrocarbon compound, as the organic compound containing C-H.Fuel streams 605 also optionally can contain H ₂and/or CO, as the H provided by optional anode recirculation stream 685 ₂and/or CO.Point out, anode recirculation stream 685 is optional, and in many aspects in, not have directly or by being combined with fuel streams 605 or fuel reforming stream 615 and indirectly getting back to the recirculation flow of anode 627 from anode exhaust 625.In the reformed, fuel reforming stream 615 can be sent into the anode 627 of fuel cell 620.Also CO will can be contained ₂and O ₂stream 619 send into negative electrode 629.From the carbanion stream 622 (CO of the cathode portion 629 of fuel cell ₃ ^2-) can provide anode fuel cell react needed for remaining reaction thing.Based on the reaction in anode 627, gained anode exhaust 625 can comprise H ₂o, CO ₂, be equivalent to one or more components (H of the fuel of incomplete reaction ₂, CO, CH ₄or other component corresponding with reformable fuel) and choose any one kind of them or multiple extra non-reactive component, as N ₂and/or other pollutent of a part as fuel streams 605.Then anode exhaust 625 can be sent into one or more segregation section.Such as, CO ₂the section of removing 640 can be equivalent to deep cooling CO ₂remove system, for removing sour gas, as CO ₂the amine section of washing or for separation of C O from anode exhaust ₂the CO of another suitable type of output stream 643 ₂segregation section.Optionally, anode exhaust can first through water-gas shift 630 with any CO will existed in anode exhaust (with some H ₂o is together) change into CO in the anode exhaust 635 of optional water-gas shift ₂and H ₂.Depend on CO ₂the character of the section of removing, water condensation or the section of removing 650 may be desirable to export stream 653 except anhydrating from anode exhaust.Although what show in figure 6 is at CO ₂after segregation section 640, but it optionally can be positioned at CO ₂before segregation section 640.In addition, spendable optionally for separating of H ₂membrane sepn section 660 to generate H ₂high-purity penetrant stream 663.Gained retentate stream 666 can be used as the input of chemical synthesis process subsequently.In addition or or, stream 666 can convert with by H in the second water-gas shift 631 ₂, CO and CO ₂content is adjusted to different ratio, produces the output stream 668 being further used for chemical synthesis process.In figure 6, display be take out anode recirculation stream 685 from retentate stream 666, but in addition or or, can in various segregation section or between other take out anode recirculation stream 685 in position easily.In addition or or, segregation section and shift-converter can configure with different order and/or with parallel construction.Finally, the output that can be used as negative electrode 629 generates the CO with reduction ₂the stream 639 of content.For the sake of simplicity, the various compression come in handy in the method and heat supply/add or the section of removing except hot arc and steam is not shown.

As mentioned above, antianode is vented various types of separation of carrying out and can carries out with any order easily.Fig. 7 shows the example of another order that antianode exhaust is carried out being separated.In the figure 7, first anode exhaust 625 can be sent into segregation section 760 to remove a part of 763 hydrogen contents from anode exhaust 625.This such as can reduce the H of anode exhaust ₂content is to provide the H had close to 2:1 ₂the retentate 766 of/CO ratio.Then in water gas shift stage 730, H can be regulated further ₂/ CO ratio is to realize desirable value.Then the output 735 of water-gas shift can be passed through CO ₂segregation section 740 and the section of dewatering 750 are to produce the output stream 775 being suitable as the charging of required chemical synthesis process.Optionally can impose additional water gas shift stage (not shown) to output stream 775.A part exports stream 775 and can optionally recirculation (not shown) input to anode.Certainly, export based on the anode with required composition, other combination of segregation section and sequence can be utilized to generate stream.For the sake of simplicity, the various compression come in handy in the method and heat supply/add or the section of removing except hot arc and steam is not shown.

negative electrode input and output

Traditionally, molten carbonate fuel cell can be run based on extracting while consuming a part of fuel be sent in the fuel streams of anode required load.Then the air that the fuel by this load, anode inputs, provide to negative electrode and CO ₂with the voltage of the internal resistance determination fuel cell of fuel cell.Be sent to the CO of negative electrode ₂anode exhaust can be partly used to provide as the input of negative electrode at least partially stream traditionally.On the contrary, the present invention antianode input and negative electrode input can use and separate/different source.Contact directly by eliminate between anode inlet flow and the composition of negative electrode inlet flow any, the additional option of fuel cell operation can be provided for, such as to generate excess syngas, to improve the total efficiency (electricity+chemomotive force) etc. of collecting carbonic anhydride and/or improvement fuel cell.

In molten carbonate fuel cell, the electrolytical carbanion transmission striden across in fuel cell can provide from the first flowing-path to the second flowing path transmission CO ₂method, wherein this transmission method can allow from low concentration (negative electrode) to higher concentration (anode) transmit, this can therefore be conducive to trap CO ₂.This fuel cell is to CO ₂the selectivity part be separated can based on the electrochemical reaction that this battery can be made to generate electric power.For the non-reacted thing class of the electrochemical reaction effectively do not participated in fuel cell (as N ₂), unconspicuous reacting weight and the transmission from negative electrode to anode can be there is.On the contrary, current potential (voltage) difference between negative electrode and anode can provide the strong motivating force across fuel cell transmission carbanion.Therefore, the carbanion transmission in molten carbonate fuel cell can allow with relatively high selectivity from negative electrode (lower CO ₂concentration) anode (higher CO ₂concentration) transmit CO ₂.But use a challenge of molten carbonate fuel cell carbon dioxide removal to be, fuel cell has the limited ability removing carbonic acid gas from relatively rare negative electrode charging.Along with CO ₂density loss to about 2.0 below volume %, quick reduction the voltage generated by carbonate fuel battery and/or power.Along with CO ₂concentration reduces further, such as, drop to about 1.0 below volume %, and at a time, the voltage striding across fuel cell becomes enough low so that the further transmission of carbonate almost or completely can not occur and fuel cell.Therefore, under the operational conditions of commericially feasible, at least some CO may be there is in the exhaust of the negative electrode section of fuel cell ₂.

In addition or or, other possible source of negative electrode input stream comprises biological CO processed ₂source.This can comprise such as, the CO generated in the course of processing of bio-derived compounds ₂, as the CO generated in ethanol production process ₂.Example that is additional or that substitute can comprise the burning by biology fuel, the CO that the burning as lignocellulose generates ₂.Other possible CO that are additional or that substitute ₂source can be equivalent to output from various industrial technology or evacuation circuit, as generated by the manufacturing installation of steel, cement and/or paper containing CO ₂stream.

Another possible CO that is additional or that substitute ₂source can be from fuel cell containing CO ₂stream.From fuel cell containing CO ₂stream can be equivalent to export stream from the negative electrode of different fuel battery, exports stream from the anode of different fuel battery, outputs to the recycle stream of negative electrode input and/or output to the recycle stream of negative electrode input from the anode of fuel cell from the negative electrode of fuel cell.Such as, the MCFC run in a standalone mode under conventional conditions can generate the CO with at least about 5 volume % ₂the cathode exhaust gas of concentration.Like this containing CO ₂cathode exhaust gas can be used as the MCFC run according to an aspect of the present invention negative electrode input.More generally, the CO produced from cathode exhaust gas can additionally or alternatively be used ₂the fuel cell of other type exported, and be not reacted by " burning " and/or other type that burning energy supply generator generates contain CO ₂stream.Optionally but preferably, from another fuel cell containing CO ₂stream can from another molten carbonate fuel cell.Such as, for the molten carbonate fuel cell of series connection with regard to negative electrode, the output from the negative electrode of the first molten carbonate fuel cell can be used as the input of the negative electrode of the second molten carbonate fuel cell.

CO is contained for from the various types of of the source beyond Combustion Source ₂stream, the CO of this stream ₂content can change to a great extent.The CO of negative electrode input stream ₂content can contain the CO of at least about 2 volume % ₂, as at least about 4 volume %, or at least about 5 volume %, or at least about 6 volume %, or at least about 8 volume %.In addition or or, negative electrode input stream CO ₂content can be about 30 volume % or lower, as about 25 volume % or lower, or about 20 volume % or lower, or about 15 volume % or lower, or about 10 volume % or lower, or about 8 volume % or lower, or about 6 volume % or lower, or about 4 volume % or lower.For some higher CO ₂the stream of content, CO ₂content higher than about 30 volume %, can only attach the basic by CO of other compound measured as contained ₂the stream formed.Such as, the internal combustion turbine without exhaust gas recirculatioon can produce the CO with about 4.2 volume % ₂the exhaust stream of content.Under EGR, internal combustion turbine can produce the CO with about 6-8 volume % ₂the exhaust stream of content.The stoichiometric(al) combustion of methane can produce the CO with about 11 volume % ₂the exhaust stream of content.Burning of coal can produce the CO with about 15 – 20 volume % ₂the exhaust stream of content.Use the fired heater of refinery flares can produce the CO with about 12 – 15 volume % ₂the exhaust stream of content.Without can producing with the internal combustion turbine that low BTU gas runs of any EGR, there is ~ the CO of 12 volume % ₂the exhaust stream of content.

Except CO ₂outward, negative electrode input stream also must comprise O ₂to provide cathodic reaction necessary component.Some negative electrodes input stream can based on using air as component.Such as, burning and gas-exhausting stream is formed by burning hydrocarbon fuels in the presence of the air.The negative electrode input stream of this burning and gas-exhausting stream or the another type owing to comprising air with oxygen level can have about 20 volume % or lower, as about 15 volume % or lower, or the oxygen level of about 10 volume % or lower.In addition or or, the oxygen level of negative electrode input stream can be at least about 4 volume %, as at least about 6 volume %, or at least about 8 volume %.More generally, negative electrode input stream can have the oxygen level being applicable to carry out cathodic reaction.In certain aspects, this can be equivalent to about 5 volume % to about 15 volume %, as the oxygen level of about 7 volume % to about 9 volume %.For being permitted eurypalynous negative electrode input stream, CO ₂and O ₂total amount can be equivalent to this input stream be less than about 21 volume %, as this stream be less than about 15 volume % or this stream be less than about 10 volume %.Can will contain oxygen airflow and the CO with low oxygen content ₂source merges.Such as, the exhaust stream generated by coal combustion can comprise low oxygen content, and it can form cathode inlet stream with air mixed.

Except CO ₂and O ₂outward, negative electrode input stream can also by inertia/non-reacted thing class, as N ₂, H ₂o and other typical oxygenant (air) component are formed.Such as, for the negative electrode input be vented derived from combustion reactions, if use air as a part for the oxidant source for combustion reactions, then this exhaust can comprise the typical component of air, as N ₂, H ₂o and other compound being present in the minor amount in air.Depend on the character of the fuel source for combustion reactions, the annexation class existed after the burning based on fuel source can comprise H ₂o, oxynitride (NOx) and/or oxysulfide (SOx) and be present in other compound of the partially or completely products of combustion in fuel and/or as the compound existed in fuel, as one or more in CO.These thing classes can exist, although total they may reduce cathodic activity with the amount of not Poisoning cathode catalyst surface.It may be acceptable that such performance reduces, or will reduce to acceptable level with cathod catalyst interactional thing class by known pollutant removal technology.

The O existed in negative electrode input stream (the negative electrode input stream as based on burning and gas-exhausting) ₂amount can advantageously be enough to provide the oxygen needed for the cathodic reaction in fuel cell.Therefore, O ₂volume percent can be advantageously CO in this exhaust ₂at least 0.5 times that measures.Optionally, if necessary, additional air can be added to provide enough oxygenants to cathodic reaction in negative electrode input.When using the air of certain form as oxygenant, the N in cathode exhaust gas ₂amount can be at least about 78 volume %, such as at least about 88 volume %, and/or about 95 volume % or lower.In certain aspects, negative electrode input stream can additionally or alternatively contain the compound being usually regarded as pollutent, as H ₂s or NH ₃.In in other, negative electrode input stream can be purified to reduce or to be minimized by the content of this pollutant.

Except the reaction for the formation of the carbanion across electrolyte transport, the condition in negative electrode is also applicable to and conversion of nitrogen oxides is become nitrate and/or nitrate ion.For simplicity, only nitrate ion is mentioned below.Gained nitrate ion also can across electrolyte transport for the reaction in anode.NOx concentration in negative electrode input stream can be ppm level usually, and therefore this nitrate radical transmission reaction can have minimal effects to the amount of the carbonate across electrolyte transport.But this NOx removal method can be useful to the negative electrode input stream based on the burning and gas-exhausting from internal combustion turbine, because this can provide the mechanism reducing NOx emission.In addition or or, the condition in negative electrode is applicable to and unburned hydrocarbon (is inputted the O in stream with negative electrode ₂in conjunction with) change into typical combustion product, as CO ₂and H ₂o.

The temperature being applicable to run MCFC can be about 450 DEG C to about 750 DEG C, as at least about 500 DEG C, and the temperature in of such as about 550 DEG C and the temperature out of about 625 DEG C.Before entering negative electrode, heat can be introduced to burning and gas-exhausting, if or need, from burning and gas-exhausting, heat extraction is with such as to other technique (reformation that the fuel as anode inputs) heat supply.Such as, if the source of negative electrode input stream is burning and gas-exhausting stream, the temperature of this burning and gas-exhausting stream can be greater than the temperature required of cathode inlet.This on the one hand in, can before being used as negative electrode input stream from burning and gas-exhausting heat extraction.Such as, or this burning and gas-exhausting can under extremely low temperature, and after the wet gas scrubber on coal firing boiler, this burning and gas-exhausting can lower than about 100 DEG C in this case.Or this burning and gas-exhausting can from the exhaust of the internal combustion turbine of combined cycle mode operation, wherein this gas by generating steam to run steam turbine additional power to cool.In this case, this gas can lower than about 50 DEG C.Heat can be introduced to the burning and gas-exhausting colder than expection.

fuel cell arrangement

In in various, a config option of fuel cell (fuel cell array as containing multiple fuel cell pack) can be distribute containing CO between multiple fuel cell ₂stream.Relative to the capacity of single fuel cell, containing CO ₂the source of some types of stream can generate high volume flow rate.Such as, relative to the desirable operational conditions of single MCFC of Sizes, from industrial combustion source containing CO ₂output stream usually can be equivalent to large discharge volume.Replace processing whole stream in single MCFC, this stream can be distributed between multiple MCFC unit, wherein at least some usually can be in parallel, to make flow velocity in each unit within the scope of required flow rate.

Second config option can be utilize the fuel cell of series connection in succession to remove CO from flowing stream ₂.No matter contain CO ₂the initial fuel cell number that stream can in parallel be assigned to is how many, can be that one or more balancing cells of series connection are to remove extra CO further after each initial fuel cell ₂.The CO during if negative electrode exports ₂aequum is enough low, attempts from negative electrode input stream, removing CO in single fuel cell or Fuel cell segments ₂the low of fuel cell and/or uncertain voltage can be caused to export to desired level.Be different from and attempt removing CO in single fuel cell or Fuel cell segments ₂to desired level, CO can be removed in continuous print battery ₂until can desired level be realized.Such as, each battery in a succession of fuel cell can be used for the CO removing the certain percentage (such as about 50%) existed in fuel streams ₂.In such instances, if series connection use three fuel cells, CO can be reduced ₂(be such as down to about 15% or lower of original amount, this process that can be equivalent to three fuel cells through connecting is by CO for concentration ₂concentration is down to about 1% or lower from about 6%).

In another configuration, can operational conditions be selected to provide required output voltage in the comparatively early fuel section of series connection, simultaneously can the section of selection array to realize required carbon separation of level.Such as, the fuel cell array of three fuel cells with series connection can be used.Removing CO while the first two fuel cell of series connection is used in and keeps required output voltage ₂.Then last fuel cell can be run to remove CO ₂to desired concn, but at the lower voltage.

Again one configuration in, the anode in fuel cell array can be connected separately with negative electrode.Such as, if fuel cell array comprises the fuel cell cathode of series connection, corresponding anode can connect in any convenient manner, and layout that need not be identical with their respective cathode matches.This can comprise, and such as, is connected in parallel anode, with the fuel-feed making each anode receive identical type, and/or differential concatenation jointed anode, to make the highest fuel concentration in anode corresponding to having minimum CO ₂those negative electrodes of concentration.

In another configuration, can control be sent to the fuel quantity of one or more anode segment and/or be sent to the CO of one or more negative electrode section ₂amount is with the performance improving fuel cell array.Such as, fuel cell array can have multiple negative electrode sections of series connection.In the array of three negative electrode sections comprising series connection, this might mean that the output from the first negative electrode section can be equivalent to the input of the second negative electrode section, the output from the second negative electrode section can be equivalent to the input of the 3rd negative electrode section.In this type of configuration, CO ₂concentration can reduce with each negative electrode section in succession.In order to compensate the CO of this reduction ₂concentration, can send into additional hydrogen and/or methane to the anode segment corresponding with follow-up negative electrode section.Additional hydrogen in the anode corresponding with follow-up negative electrode section and/or methane can compensate at least partly by the CO reduced ₂the voltage that concentration causes and/or current loss, this can improve the voltage that produced by this fuel cell and therefore improve pure horsepower.In another example, the negative electrode in fuel cell array can sections in series and part in parallel.In such example, replace the negative electrode whole burning exported in feeding first negative electrode section, burning and gas-exhausting at least partially can be sent into follow-up negative electrode section.This can provide the CO of raising in follow-up negative electrode section ₂content.If needed, anode section or negative electrode section can be used to send into other option of variable feed.

As mentioned above, the negative electrode of fuel cell can be equivalent to the multiple negative electrodes from fuel cell array.In certain aspects, can fuel cell operation array with improve or make from negative electrode anode transfer carbon amounts maximize.In in such, (usually at least arranged in series is comprised for from array sequence, or last (multiple) negative electrode is identical with initial (multiple) negative electrode) in the negative electrode of last (multiple) negative electrode export, export to form and can comprise about 2.0 volume % or less CO ₂the CO of (such as, the less or about 1.2 volume % of about 1.5 volume % or less) and/or at least about 1.0 volume % ₂, as at least about 1.2 volume % or at least about 1.5 volume %.Due to this restriction, CO during use molten carbonate fuel cell ₂the net efficiency removed can be depending on the CO in negative electrode input ₂amount.For CO ₂content is greater than about 6 volume %, as the negative electrode input stream of at least about 8%, to removable CO ₂quantitative limitation is not strict.But, for using Sweet natural gas as fuel and the combustion reactions using excess air as common in internal combustion turbine, the CO in burning and gas-exhausting ₂amount only may be equivalent to the CO of negative electrode input ₂concentration is less than about 5 volume %.The use of exhaust gas recirculatioon can make the CO of negative electrode input ₂amount brings up at least about 5 volume %, such as at least about 6 volume %.If use Sweet natural gas as improving EGR during fuel to produce the CO exceeding about 6 volume % ₂concentration, then the combustibility in burner can reduce and internal combustion turbine becomes unstable.But, by H ₂when adding in fuel, flammable window can be significantly improved, improve the amount of exhaust gas recirculatioon with activation further, thus the CO of negative electrode input can be realized ₂concentration is at least about 7.5 volume % or at least about 8 volume %.Such as, limit is removed, by the CO of negative electrode input based on the about 1.5 volume % in cathode exhaust gas place ₂content is brought up to about 7.5 volume % from about 5.5 volume % and can be equivalent to available fuel battery and trap and be transferred to plate tank with final separation of C O ₂cO ₂amount increases ~ 10%.In addition or or, can reduce negative electrode export in O ₂amount, it typically is and the CO removed ₂measure proportional amount, this can cause the small size corresponding raising of the amount of other (non-cathodic reaction) thing class of cathode outlet place.

In in other, can fuel cell operation array to improve or to make the energy output of fuel cell, as total energy export, electric energy exports, syngas chemistry energy output or its combination maximize.Such as, can with excessive reformable operating fuel molten carbonate fuel cell in various situation, as generating for the synthetic gas stream of chemical synthesizer and/or for generating high-purity hydrogen stream.This synthetic gas stream and/or hydrogen stream can be used as synthetic gas source, hydrogen source, clean fuel source and/or for other purposes easily any.In in such, the CO in cathode exhaust gas ₂amount can input the CO in stream with negative electrode ₂amount and the CO under required operational conditions ₂utilization ratio is associated to improve or make fuel cell energy to export and maximizes.

In addition or or, depend on operational conditions, MCFC can by the CO of cathode exhaust gas stream ₂content is down to about 5.0 volume % or lower, such as about 4.0 volume % or lower, or about 2.0 volume % or lower, or about 1.5 volume % or lower, or about 1.2 volume % or lower.In addition or or, the CO of cathode exhaust gas stream ₂content can be at least about 0.9 volume %, as at least about 1.0 volume %, or at least about 1.2 volume %, or at least about 1.5 volume %.

molten carbonate fuel cell runs

In certain aspects, can with one way or once by mode operation fuel cell.In single pass mode, do not send the reformate in anode exhaust back to anode inlet.Therefore, in one way is run, synthetic gas, hydrogen or some other products are not directly recycled to anode inlet from anode output.More generally, in one way is run, the reformate in anode exhaust does not also send anode inlet back to indirectly, as the fuel streams by utilizing reformate processing to introduce anode inlet subsequently.Optionally, from the CO of anode export ₂cathode inlet is recycled in the process can run with single pass mode at MCFC.More generally, in other, for the MCFC run with single pass mode, the recirculation from anode export to cathode inlet may be there is.In addition or or, the heat from anode exhaust or output can recirculation in single pass mode.Such as, anode output stream can be passed through heat exchanger, and anode is exported cooling with heat exchanger and by another stream, the input stream as anode and/or negative electrode is heated.Heat from anode is recycled to fuel cell and is in one way or once consistent by operating use.Optionally but not preferably, in single pass mode can the composition that exports of combusting anode with to fuel cell heat supply.

Fig. 2 shows an illustrative example of the operation for the MCFC generated electricity.In fig. 2, the anode part of fuel cell can receive fuel and steam (H ₂o) as input, and water, CO is exported ₂with optional excessive H ₂, CH ₄(or other hydrocarbon) and/or CO.The cathode portion of fuel cell can receive CO ₂with some oxygenants (such as air/O ₂) as input, export the CO of the reducing amount be equivalent in the oxygenant (air) of oxygen deprivation ₂.In fuel cell, at the CO that cathode side is formed ₃ ^2-ion can across electrolyte transport be provided in anode place occur reaction needed for carbanion.

At molten carbonate fuel cell, in example fuel cell as shown in Figure 2, some reactions can be there is.And if reforming reaction can be optionally provide enough H directly to anode ₂, then can reduce or save reforming reaction.Following reaction is based on CH ₄, but when using other fuel in a fuel cell, similar reaction can be there is.

(1) < anode reformation >CH ₄+ H ₂o=>3H ₂+ CO

(2) < water-gas shift >CO+H ₂o=>H ₂+ CO ₂

(3) the combination >CH of < reformation and water-gas shift ₄+ 2H ₂o=>4H ₂+ CO ₂

(4) < anode H ₂oxidation >H ₂+ CO ₃ ^2-=>H ₂o+CO ₂+ 2e ^-

(5) < negative electrode >1/2O ₂+ CO ₂+ 2e ^-=>CO ₃ ^2-

Reaction (1) represents basic hydrocarbon reforming reaction to generate the H for the anode of fuel cell ₂.The CO formed in reaction (1) changes into H by water gas shift reaction (2) ₂.The combination of reaction (1) and (2) is shown as reaction (3).Reaction (1) and (2) can be carried out outside fuel cell, and/or reforms and can carry out in anode.

Reaction (4) respectively at anode and negative electrode place and (5) represent the reaction causing the electric power in fuel cell to occur.Reaction (4) will be present in charging or the H optionally generated by reaction (1) and/or (2) ₂merge to form H with carbanion ₂o, CO ₂with the electronics being sent to this circuit.Reaction (5) makes O ₂, CO ₂merge with the electronics from this circuit and form carbanion.The carbanion generated by reaction (5) can across the electrolyte transport of fuel cell to provide the carbanion needed for reaction (4).Combine across electrolytical transmission with carbanion, then by providing electrical connection to form closing current loop between the anode and cathode.

In various embodiments, the target of fuel cell operation can be improve the total efficiency of fuel cell and/or the total efficiency of fuel cell+integrated chemical synthesis technique.This tradition being usually different from fuel cell is run, and wherein target can be for utilizing the fuel power generation function of supply battery with high electrical efficiency fuel cell operation.As defined above, by the electricity of fuel cell is exported add low heat value that fuel cell exports again divided by the low heat value of the input component of fuel cell to determine total fuel cell efficiency.In other words, TFCE=(LHV (el)+LHV (sgout))/LHV (in), wherein LHV (in) and LHV (sgout) refers to that the fuel element being sent to fuel cell is (as H respectively ₂, CH ₄and/or CO) and anode export stream or stream in synthetic gas (H ₂, CO and/or CO ₂) LHV.This can provide measuring of the electric energy+chemical energy of fuel cell and/or integrated chemical Process Production.Point out, under this definition of total efficiency, the heat energy used in that use in fuel cell and/or integrated fuel cell/chemosynthesis system can have contribution to total efficiency.But this definition does not comprise and exchanging or any excessive heat of otherwise taking out from fuel cell or integrated fuel cell/chemosynthesis system.Therefore, if from fuel cell excessive heat such as generating steam to be generated electricity by steam turbine, then do not comprise such excessive heat in the definition of total efficiency.

Some operating parameters can be controlled with excessive reformable operating fuel fuel cell.Some parameters can be similar at present to the parameter that fuel cell operation is recommended.In certain aspects, the cathode conditions of fuel cell and temperature input can be similar to those that recommend in document.Such as, required electrical efficiency and required total fuel cell efficiency can be realized within the scope of the typical temperature of fuel cell operation of molten carbonate fuel cell.In typical operations, temperature can improve across fuel cell.

In in other, the operating parameter of fuel cell can deviate from representative condition thus fuel cell operation reduces from anode inlet to anode export and/or from cathode inlet to cathode outlet to make temperature.Such as, hydrocarbon is changed into H ₂thermo-negative reaction with the reforming reaction of CO.If relative to the amount of oxidation of the hydrogen for generation of electric current, in anode of fuel cell, carry out enough reformations, then the net heat balance in this fuel cell can be heat absorption.This can cause the cooling between the entrance of fuel cell and outlet.In heat absorption operational process, the temperature that can control in fuel cell reduces to make the ionogen in fuel cell keep molten state.

The composition of the fuel that the parameter that can control to be different from the mode of recommending at present can comprise fuel quantity that anode provides, anode provides and/or not having synthetic gas to be significantly recycled to anode input or negative electrode input from anode exhaust anode export in the separation of synthetic gas and trapping.In certain aspects, synthetic gas or hydrogen can not have been allowed directly or indirectly to be recycled to anode input or negative electrode input from anode exhaust.In in additional or substituting, limited amount recirculation can be there is.In in such, from anode exhaust to anode, the recirculation volume of input and/or negative electrode input can be less than about 10 volume % of anode exhaust, as being less than about 5 volume % or being less than about 1 volume %.

In addition or or, the target of fuel cell operation can be except generating is outer also from combustion reactions or generation CO ₂export separation of C O in the output stream of another technique of stream ₂.In in such, combustion reactions can be used for one or more generator or turbine energy supply, and this can provide the most of power generated by magnet synthetic electricity generator/fuel cell system.Be different from fuel cell operation to optimize by fuel cell power generation, this system can be run with in the trapping of carbonic acid gas reducing or improve while being minimized by the fuel cell number needed for capturing carbon dioxide auto-combustion energy supply generator.Select the suitable configuration of the input and output stream of fuel cell and select the suitable operational conditions of fuel cell can realize the desirable combination of total efficiency and carbon trapping.

In some embodiments, can fuel cell in fuel arranged array the fuel cell (as fuel cell pack) of single section only can be there is.In such embodiment, this anode fuel utilization ratio of single section can represent the anode fuel utilization ratio of this array.Another option can be that fuel cell array can contain multiple anode segment and multiple negative electrode section, wherein each anode segment has the fuel availability in same range, as each anode segment has within 10% of prescribed value, such as, fuel availability within 5% of prescribed value.An option can be that each anode segment can have and equals prescribed value or a certain amount of following fuel availability lower than prescribed value again, equals prescribed value or less than prescribed value 10% or lower, such as 5% or lower as made each anode segment.As an illustrative examples, the fuel cell array with multiple anode segment can make each anode segment within about 10% of 50% fuel availability, and this is equivalent to the fuel availability that each anode segment has about 40% to about 60%.As another example, the fuel cell array with multiple sections can make each anode segment for being not more than 60% anode fuel utilization ratio, and maximum deviation is little by about 5%, and this is equivalent to the fuel availability that each anode segment has about 55% to about 60%.In an example again, the one or more Fuel cell segments in fuel cell array can be run with the fuel availability of about 30% to about 50%, as run the multiple Fuel cell segments in this array with the fuel availability of about 30% to about 50%.More generally, the scope of any the above-mentioned type can be matched with any anode anode fuel utilization value specified herein.

Another option that is additional or that substitute can comprise to and not all anode segment specified fuels utilization ratio.Such as, in some aspects of the invention, can at least partially in fuel arranged battery in one or more arranged in series/pile with to other anode segment regulation anode fuel utilization ratio easily any in the second anode section in the first anode section in series connection, series connection, last anode segment in series connection or series connection." first " section in series connection used herein to be equivalent to it from fuel source direct charging input section (if or this layout also containing section in parallel, the then section of being group), follow-up (" second ", " the 3rd ", " finally " etc.) Duan represent with to its charging from the output of one or more formerly section non-immediate from the section of respective fuel source.In the output from formerly section with when directly jointly feeding a section from both inputs of fuel source, " first " (group) section and " last " (group) section can be had, but more difficult between other section (" second ", " the 3rd " etc.) foundation order (such as, under these circumstances, by one or more components in compound input feed composition, such as CO ₂concentration level determine numeric order, from maximum concentration " first " to minimum concentration " finally ", represent identical sequencing level with roughly similar composition difference).

An option that is additional or that substitute can be specify the anode fuel utilization ratio (again, wherein fuel cell/heap still can at least partially in one or more arranged in series arrange) corresponding with particular cathode section again.As mentioned above, based on the flow direction in anode and negative electrode, the first negative electrode section can not correspond to first anode section (can not stride across identical fuel cell membranes with first anode section).Therefore, in some aspects of the invention, can to other negative electrode section regulation anode fuel utilization ratio easily any in the second negative electrode section in the first negative electrode section in series connection, series connection, last the negative electrode section in series connection or series connection.

Another option that is additional or that substitute can be the population mean of the fuel availability of all fuel cells in specified fuels array.In in various, the population mean of the fuel availability of fuel cell array can be about 65% or lower, such as about 60% or lower, about 55% or lower, about 50% or lower, or about 45% or lower (in addition or or, the overall average fuel availability of fuel cell array can be at least about 25%, such as at least about 30%, at least about 35%, or at least about 40%).This average fuel utilization ratio does not need to limit the fuel availability in arbitrary single hop, as long as this fuel cell array meets required fuel availability.

cO after trapping ₂ the purposes exported

Of the present invention various in, said system and method can allow as pressure fluid produce carbonic acid gas.Such as, the CO generated by low temperature separation process section ₂can be equivalent to have at least about 90% at first, such as at least about 95%, at least about 97%, at least about 98% or the pressurization CO of at least about 99% purity ₂liquid.This pressurization CO ₂stream can such as recovering the oil or gas production, as in secondary oil recovery to strengthen further in Injection Well.When implementing near the facility comprising internal combustion turbine, whole system can benefit from extra synergy in the application of electric power/mechanical power and/or integrated with the heat of whole system.

Or, for the system (not namely being incorporated in the tubing system with strict composition standard) being exclusively used in intensified oil reduction (EOR) purposes, obviously CO can be loosened ₂separation requirement.EOR purposes can to O ₂existence responsive, therefore in some embodiments, the CO of EOR is used for ₂can not O be there is in stream ₂.But EOR purposes can often to CO, H of dissolving ₂and/or CH ₄there is Wheat Protein.Conveying CO ₂pipeline also may be responsive to these impurity.These dissolved gasess usually can to the CO for EOR ₂solubilising only have minor impact.As EOR gas inject CO, H ₂and/or CH ₄and so on gas fuel value can be caused to reclaim certain loss of (fuelvaluerecovery), but these gases may be compatible with EOR purposes in other side.

In addition or or, CO ₂can be used as bioprocess technology as one of fluid under pressure possible purposes, as the nutrient substance in algal grown/results.MCFCs is used for CO ₂separation can guarantee that the biologically important pollutent of great majority can be reduced to acceptable low-level, only has other " pollution " gas that can not affect to significant adverse ptotoautotroph growth on a small quantity (as CO, H to produce ₂, N ₂deng and their combination) containing CO ₂stream.This and the most industry output stream generated of originating forms sharp contrast, and the output stream that most industry source generates usually can containing likely high malicious material, as heavy metal.

In in this type of the present invention, in plate tank, pass through CO ₂separation generate CO ₂stream can be used for producing biofuel and/or chemical and their precursor.Again in addition or or, CO ₂can be used as dense fluid to generate, extend across distance pumping and transport so that much easier, such as, transport the land for growing field crops (largefields) of ptotoautotroph to.The addition of C O containing mixing with other gas and pollutent can be discharged in conventional exhaust source ₂the hot gas of (such as about 4-15%).These materials need as rarefied gas pump usually toward the algae pool or biofuel " farm ".On the contrary, MCFC system of the present invention can produce concentrated CO ₂stream (based on dry-basis, ~ 60-70 volume %), it can be concentrated into 95%+ (such as 96%+, 97%+, 98%+ or 99%+) further and easily liquefy.This stream then can with the easily also long-distance transportation also big area distribution effectively effectively of relatively low cost.In these embodiments, from Combustion Source/MCFC waste heat also accessible site in whole system.

Another embodiment can be adopted, wherein CO ₂source/MCFC and biology/chemical production scene in the same place.In this case, minimal compression may be only needed (namely to provide the CO being enough to be used in biological production ₂pressure, such as about 15psig to about 150psig).Several new arrangement may be had in this case.Optionally antianode exhaust can apply secondary reformed to reduce CH ₄content, and additionally or alternatively optionally can there is water-gas shift and become CO to order about any residue CO ₂and H ₂.

The component exporting stream and/or negative electrode output stream from anode can be used for various uses.An option can be use anode to export as hydrogen source as mentioned above.For the MCFC integrated or in the same place with refinery, this hydrogen can be used as various refinery processes, as the hydrogen source of hydrotreatment.Another option can be additionally or alternatively use hydrogen as fuel source, wherein carrys out the CO of auto-combustion ₂by " trapping ".Such hydrogen can be used as the fuel of boiler, stove and/or fired heater in refinery or other industrial plants, and/or this hydrogen can be used as generator, as the charging of turbine.Hydrogen from MCFC fuel cell also can additionally or alternatively as the input stream needing hydrogen as the fuel cell (may comprise fuel cell powered vehicle) of other type of input.Another option can be that the synthetic gas being additionally or alternatively used as the output of MCFC fuel cell to generate inputs as fermentation.

Another option can be additionally or alternatively use to export by anode the synthetic gas generated.Certainly, synthetic gas can be used as fuel, although synthetic gas base fuel is generating some CO as still causing during fuel combustion ₂.In in other, synthetic gas exports the input that stream can be used as chemical synthesis process.An option can be another technique additionally or alternatively synthetic gas being used for fischer-tropsch technique and/or being formed larger hydrocarbon molecule by synthetic gas input.Another option can be additionally or alternatively use synthetic gas to form intermediate product, as methyl alcohol.Methyl alcohol can be used as final product, but in other in the methyl alcohol that generated by synthetic gas can be used for generating more large compound, as gasoline, alkene, aromatic hydrocarbons and/or other product.Point out, methanol synthesizing process and/or use transformation catalyst Fischer-tropsch process synthetic gas charging in, a small amount of CO ₂acceptable.Hydroformylation is an example adding or substitute of the another synthesis technique that synthetic gas can be utilized to input.

Point out, generating a change of synthetic gas to using MCFC can be use MCFC fuel cell as the system for processing methane that offshore oil platform takes out and/or Sweet natural gas or the part apart from its final market other production system quite far away.Not attempt gas phase output or this gas-phase product of standing storage that transport carrys out artesian well, but can use the input of gas phase output as MCFC fuel cell array of artesian well.This can bring various benefit.First, the power supply of this platform is can be used as by the electric power of this fuel cell array column-generation.In addition, the synthetic gas from this fuel cell array exports the input that can be used as the Fischer-tropsch process of production scene.This can form the liquid hydrocarbon product transporting such as shore facilities or larger terminal more easily by pipeline, boats and ships or rail car from production scene to.

Other integrated options additionally or alternatively can comprise the source using negative electrode output as more highly purified heated nitrogen.Negative electrode input can comprise most air usually, this means can comprise quite a few nitrogen in negative electrode input.Fuel cell can from negative electrode across ionogen anode conveying CO ₂and O ₂, and cathode outlet can have than CO low in air ₂and O ₂concentration and therefore higher N ₂concentration.Removing residual O subsequently ₂and CO ₂when, this nitrogen exports and can be used as the production of ammonia or other nitrogenous chemical, as the charging of urea, ammonium nitrate and/or nitric acid.Point out, urea synthesis additionally or alternatively can use the CO be separated from anode exports ₂as input charging.

integration Data Model example: with the purposes that combustion gas turbine is integrated

In some aspects of the invention, for generating electricity and discharging containing CO ₂the Combustion Source of exhaust can be integrated with the operation of molten carbonate fuel cell.An example of suitable Combustion Source is internal combustion turbine.Preferably, internal combustion turbine can with steam generation and integrated combined cycle mode combustion Sweet natural gas, methane gas or another appropriate hydrocarbon gas of recovery of heat to obtain additional efficiency.For maximum up-to-date design, modern gas theory efficiency is about 60%.Gained is containing CO ₂exhaust stream can running the temperature of compatible rising with MCFC, as 300 DEG C-700 DEG C, preferably produce at 500 DEG C-650 DEG C.Can optionally but preferably, from wherein removing the pollutent that MCFC can be made poisoning before gas source enters turbine, as sulphur.Or this gas source can be coal fired power generation machine, wherein due to pollutant level higher in exhaust, usually purify this exhaust after combustion.In this alternatives, may must carry out certain heat exchange can purify at a lower temperature to/from this gas.In additional or substituting embodiment, containing CO ₂the source of exhaust can be the output of other thermal source from boiler, burner or the rich carbon fuel that burns.In the embodiment that other are additional or substituting, containing CO ₂the source of exhaust can be the biology CO combined that originates with other ₂.

In order to integrated with Combustion Source, some alternative configurations for processing fuel-cell anode can be desirable.Such as, alternative configurations can be by least partially from the exhaust gas recirculatioon of anode of fuel cell to the input of anode of fuel cell.Output stream from MCFC anode can comprise H ₂o, CO ₂, optional CO and optionally but normally unreacted fuel (as H ₂or CH ₄) as mainly exporting component.Replace using this output stream as external fuel stream and/or the input stream integrated with another technique, stream can be exported carry out one or many and be separated with by CO by antianode ₂with the component with potential fuel value, as H ₂or CO is separated.Then the component with fuel value can be recycled to the input of anode.

Such configuration can provide one or more benefit.First, can from anode export separation of C O ₂, as passed through to use deep cooling CO ₂separator.Several component (H that anode exports ₂, CO, CH ₄) not easy condensed components, and CO ₂and H ₂o can be separated as condensation independently.According to this embodiment, the CO of at least about 90 volume % in anode output can be isolated ₂to form relatively high-purity CO ₂export stream.Or, less CO can be removed from anode exports in certain aspects ₂, therefore separable go out anode export in about 50 volume % to the CO of about 90 volume % ₂, 70 volume % as less or about in about 80 volume % or less.After isolation, the remainder that anode exports mainly can be equivalent to have the component of fuel value and the CO of reducing amount ₂and/or H ₂o.This part anode after separation export can recirculation to be used as a part for anode input together with additional fuel.In this type of configuration, even if the fuel availability in the one way through MCFC may be low, but non-fuel can advantageously recirculation with again through anode.Therefore, the level that one way fuel availability can reduce, avoids the waste of fuel (discharge) that do not fire in environment simultaneously.

Supplementing as what inputted to anode by a part of anode off-gas recirculation or substituting, another config option can be use a part of anode exhaust as turbine or other combustion unit, as the input of the combustion reactions of boiler, stove and/or fired heater.Be recycled to anode input and/or can be any convenience or desirable amount as the relative quantity that input is recycled to the anode exhaust of combustion unit.If anode off-gas recirculation is in the only one of anode input and combustion unit, then recirculation volume can be anyly to measure easily, as removing CO ₂and/or H ₂maximum 100% of the part anode exhaust stayed after any separation of O.When a part of anode exhaust had not only been recycled to anode input but also had been recycled to combustion unit, total recirculation volume can be 100% or lower of the remainder of anode exhaust by definition.Or, any of anode exhaust can be used to shunt easily.In the various embodiments of the present invention, the amount being recycled to anode input can be at least about 10%, such as at least about 25%, at least about 40%, at least about 50%, at least about 60%, at least about 75% or at least about 90% of the anode exhaust stayed after being separated.In these embodiments in addition or or, be recycled to anode input amount can for stay after being separated about 90% of anode exhaust or less, such as about 75% or less, about 60% or less, about 50% or less, about 40% or less, about 25% or less or about 10% or less.Again in addition or or, in the various embodiments of the present invention, the amount being recycled to combustion unit can be at least about 10%, such as at least about 25%, at least about 40%, at least about 50%, at least about 60%, at least about 75% or at least about 90% of the anode exhaust stayed after being separated.In these embodiments in addition or or, be recycled to combustion unit amount can for stay after being separated about 90% of anode exhaust or less, such as about 75% or less, about 60% or less, about 50% or less, about 40% or less, about 25% or less or about 10% or less.

Of the present invention in other in, in addition or or, the fuel of combustion unit can be have the inertia of increasing amount and/or in fuel, serve as the fuel of component of thinner.CO ₂and N ₂it is the example of the component of relative inertness in combustion reactions process in natural gas feed.When the inert component amount in fuel-feed reach enough level time, the performance of turbine or other Combustion Source can be affected.This impact can be partly due to the heat absorption capacity of inert component, and this tends to quenching combustion reactions.The example with the fuel-feed of enough inert component levels can comprise containing at least about 20 volume %CO ₂fuel-feed or containing at least about 40 volume %N ₂fuel-feed or containing there is the thermal capacitance of enough inertia to provide the CO of similar quenching capability ₂and N ₂the fuel-feed of combination.(to point out, CO ₂thermal capacitance higher than N ₂, the therefore CO of low concentration ₂the N with higher concentration can be had ₂similar impact.CO ₂also comparable N ₂more easily participate in combustion reactions and from this burning, remove H at this moment ₂.H ₂this consumption to the burning of fuel, there is extreme influence by reducing the flammable range of flame velocity and constriction air and fuel mixture.) more generally, for the fuel-feed containing the flammable inert component affecting fuel-feed, the inert component in this fuel-feed can be at least about 20 volume %, as at least about 40 volume %, or at least about 50 volume %, or at least about 60 volume %.Preferably, the amount of the inert component in this fuel-feed can be about 80 volume % or less.

When there is enough inert components in fuel-feed, gained fuel-feed may outside the flammable window of the fuel element of charging.In such situation, from the H of the recycling part of anode exhaust ₂add in the combustion zone of generator and can expand fuel-feed and H ₂the flammable window of combination, this can make such as containing at least about 20 volume %CO ₂or at least about 40%N ₂(or CO ₂and N ₂other combination) fuel-feed successfully burn.

Relative to the fuel-feed and the H that are sent to combustion zone ₂cumulative volume, for expanding the H of flammable window ₂amount can be fuel-feed+H ₂at least about 5 volume % of cumulative volume, as at least about 10 volume % and/or about 25 volume % or lower.Be characterized by and expand flammable window and the H that adds ₂another option of amount can based on interpolation H ₂the amount of the fuel element existed in front fuel-feed.Fuel element can be equivalent to methane, Sweet natural gas, other hydrocarbon and/or be regarded as other component of the burning turbine of energy supply or the fuel of other generator traditionally.Add the H in fuel-feed to ₂amount can be equivalent at least about 1/3 (H of 1:3 of the volume of the fuel element in fuel-feed ₂: fuel element), as at least only about half of (1:2) of the volume of fuel element.In addition or or, add the H in fuel-feed to ₂amount can be substantially equal to the volume (1:1) or lower of the fuel element in fuel-feed.Such as, for containing about 30 volume %CH ₄, about 10%N ₂with about 60%CO ₂charging, enough anode exhaust can be added in fuel-feed to realize the H of about 1:2 ₂: CH ₄ratio.To only containing H ₂idealized anode exhaust, add H ₂can produce containing about 26 volume %CH with the ratio realizing 1:2 ₄, 13 volume %H ₂, 9 volume %N ₂with 52 volume %CO ₂charging.

exhaust gas recirculatioon

Except providing exhaust with trapping and final separation of C O to fuel cell array ₂outward, the other or substituting potential use of exhaust can comprise recirculation and returns combustion reactions to improve CO ₂content.When can be used for when there being hydrogen adding in combustion reactions, Tathagata, can by the CO used in the exhaust raising combustion reactions of recirculation from the hydrogen of the anode exhaust of fuel cell array ₂content obtains further benefit.

Of the present invention various in, the exhaust gas recycling loop of power generation system can receive first part's burning and gas-exhausting, and fuel cell array can receive second section.The amount being recycled to the burning and gas-exhausting of the combustion zone of power generation system can be anyly to measure easily, as at least about 15% (by volume), and such as at least about 25%, at least about 35%, at least about 45% or at least about 50%.In addition or or, the amount being recycled to the burning and gas-exhausting of combustion zone can for about 65% (by volume) or lower, such as about 60% or lower, about 55% or lower, about 50% or lower, or about 45% or lower.

Of the present invention one or more in, the mixture of oxygenant (as air and/or oxygen-rich air) and fuel can burn also (simultaneously) mix with the stream of exhaust gas recirculation.Usually products of combustion can be comprised as CO ₂the stream of exhaust gas recirculation can be used as thinner to control, to regulate or otherwise to relax temperature of combustion and the temperature of exhaust of follow-up expansion machine can be entered.Owing to using oxygen-rich air, the exhaust of recirculation can have the CO of raising ₂content, can make decompressor run with even higher ratio of expansion under identical entrance and exhaust temperature thus, can significantly improve power thus and produce.

Gas turbine engine systems can represent an example that exhaust gas recirculation can be utilized to strengthen the power generation system of the performance of this system.Gas turbine engine systems can have first/main compressor that warp beam is connected with decompressor.This axle can be any machinery, electricity or other power connector, and a part of mechanical energy that decompressor can be made thus to generate drives main compressor.Gas turbine engine systems also can comprise the combustion chamber of the mixture being configured to combustion fuel and oxygenant.Of the present invention various in, fuel can comprise any suitable appropriate hydrocarbon gas/liquid, as synthetic gas, Sweet natural gas, methane, ethane, propane, butane, petroleum naphtha diesel oil, kerosene, aviation fuel, coal derivatived fuel, biofuel, oxygenated hydrocarbon feedstock or their any combination.Oxygenant can be derived from fluid in some embodiments and be connected to combustion chamber and second or the inlet booster that are applicable to compression charging oxygenant.In one or more embodiment of the present invention, charging oxygenant can comprise atmospheric air and/or oxygen-rich air.When oxygenant comprises only oxygen-rich air or comprise the mixture of atmospheric air and oxygen-rich air, by inlet booster compression oxygen-rich air (when mixture, before or after mixing with atmospheric air).Oxygen-rich air and/or air-oxygen-rich air mixture can have at least about 25 volume %, such as total oxygen concn of at least about 30 volume %, at least about 35 volume %, at least about 40 volume %, at least about 45 volume % or at least about 50 volume %.In addition or or, oxygen-rich air and/or air-oxygen-rich air mixture can have about 80 volume % or lower, as total oxygen concn of about 70 volume % or lower.

Oxygen-rich air can derived from any one or more in some sources.Such as, oxygen-rich air can derived from the isolation technique of such as membrane sepn, pressure-variable adsorption, Temp .-changing adsorption, nitrogen-making device by-product stream and/or their combination and so on.In addition or or, oxygen-rich air can derived from the air gas separation unit (ASU) for the production of the nitrogen for keeping pressure or other purposes, as deep cooling ASU.In certain embodiments of the invention, waste streams from this ASU can be oxygen enrichment, there is the total oxygen content of about 50 volume % to about 70 volume %, and if can be used as the needs at least partially of oxygen-rich air, dilute with unprocessed atmospheric air to obtain requisite oxygen concentration subsequently.

Except fuel and oxygenant, combustion chamber optionally also can receive the exhaust gas recirculation of compression, as mainly having CO ₂with the exhaust gas recirculatioon of nitrogen component.The exhaust gas recirculation of compression can also be applicable to the burning of accelerating oxidation agent and fuel, such as, by the temperature of gentle products of combustion derived from such as main compressor.Can recognize, the recirculation of this exhaust can be used for improving CO ₂concentration.

The exhaust of guiding expander inlet can be used as the product generation of combustion reactions.Introduce combustion reactions based on by the exhaust of recirculation at least partly, exhaust can have the CO of raising ₂content.Along with exhaust is through expander, it can generate mechanical power to drive main compressor, drive generator and/or provide power to other facility.

This power generation system also can comprise exhaust gas recirculatioon (EGR) system in many embodiments.Of the present invention one or more in, the another kind of like device that egr system can comprise heat recovery steam generator (HRSG) and/or connect with steam turbine fluid.In at least one embodiment, the combination of HRSG and steam turbine can be characterized by the closed rankine cycle of generating.Be combined with gas turbine engine systems, HRSG and steam turbine can form combined cycle power plant, as a part for gas theory (NGCC) power plant.Gaseous emissions can be introduced HRSG with the exhaust of generating steam and cooling.HRSG can comprise for be separated from exhaust stream and/or condensation of water, heat transfer to be to form steam and/or stream pressure to be adjusted to the various unit of desired level.In certain embodiments, steam can be sent to steam turbine to generate extra electric power.

At least some H is being removed with optional through HRSG ₂after O, containing CO ₂exhaust stream recirculation can be used as the input of combustion reactions in some embodiments.As mentioned above, exhaust stream can compress (or decompress(ion)) with reaction pressure needed for mating in combustion reactions container.

the example of integrated system

Fig. 8 schematically shows an example of integrated system, and it comprises and will contain CO ₂exhaust gas recirculation and from anode of fuel cell exhaust H ₂or CO introduces the combustion reactions providing power to turbine.In fig. 8, this turbine can comprise compressor 802, axle 804, decompressor 806 and combustion zone 815.Oxygen source 811 (as air and/or oxygen-rich air) and exhaust gas recirculation 898 can be merged, and compress in compressor 802 before entering combustion zone 815.Can by fuel 812, as CH ₄, and optional containing H ₂or the stream 187 of CO is sent to combustion zone.Fuel and oxygenant can react and optional but preferably by decompressor 806 to generate electric power in region 815.Exhaust from decompressor 806 can be used for formation two streams, such as, containing CO ₂stream 822 (it can be used as the input charging of fuel cell array 825) and another is containing CO ₂stream 892 (it can be used as the input of recovery of heat and steam generator system 890, and this such as can make to utilize steam turbine 894 to generate additional power becomes possibility).By heat recovery system 890, comprise from containing CO ₂the a part of H of optional removing in stream ₂after O, export stream 898 can recirculation to compress in compressor 802 or the second compressor of not showing.Can based on for CO needed for adding in combustion zone 815 ₂amount determine the exhaust of decompressor 806 for containing CO ₂the ratio of stream 892.

EGR used herein is than being that the flow velocity of fuel cell relevant portion of exhaust is divided by fuel cell relevant portion and the overall flow rate of recovery relevant portion being sent to recovery of heat producer.Such as, the EGR of the stream shown in Fig. 8 is than the overall flow rate of flow velocity divided by stream 822 and 892 being stream 822.

Can will contain CO ₂the cathode portion (not shown) of molten carbonate fuel cell array 825 sent into by stream 822.Based on the reaction in fuel cell array 825, can from stream 822 separation of C O ₂and be sent to the anode part (not shown) of fuel cell array 825.This can produce poor CO ₂negative electrode export stream 824.Then negative electrode can be exported stream 824 to send into recovery of heat (with optional vapour generator) system 850 and exchange and/or additional power to utilize steam turbine 854 (it can be optionally identical with above-mentioned steam turbine 894) Heat of Formation.After by recovery of heat and steam generator system 850, gained exhaust flow 856 can be discharged in environment and/or by the carbon trapping technique of another type, as amine washer.

At CO ₂after being transferred to anode side from the cathode side of fuel cell array 825, optionally anode can being exported 835 and send into water-gas shift 870.Water-gas shift 870 can be used for exporting with anode CO (and the H existed in 835 ₂o) be H that cost creation is extra ₂and CO ₂.Then the output from optional water-gas shift 870 can be sent into one or more segregation section 840, as ice chest or cryogenic separator.This can allow H ₂o stream 847 and CO ₂the rest part that stream 849 exports with anode is separated.The rest part 885 that anode exports can comprise by reformation generation but the unreacted H do not consumed in fuel cell array 825 ₂.Containing H ₂the first part 845 of stream 885 can be recycled to the input of the anode in fuel cell array 825.The second section 887 of stream 885 can be used as the input of combustion zone 815.Part III 865 former state can be used for another purposes and/or treated to use further subsequently.Although nearly three parts are schematically described in Fig. 8 and description herein in detail, estimate can utilize these three parts according to the present invention only one, only can utilize wherein two, maybe can utilize all these three.

In fig. 8, the exhaust for exhaust gas recycling loop is provided by the first recovery of heat and steam generator system 890, and the second recovery of heat and steam generator system 850 can be used for trapping the excessive heat exported from the negative electrode of fuel cell array 825.

Fig. 9 shows an alternative embodiment, wherein provides exhaust gas recycling loop by the identical heat recovery steam generator exported for processing fuel-cell array.In fig .9, the exhaust 998 of recirculation is provided as the part of exhaust flow 956 by recovery of heat and steam generator system 950.This can save the independent recovery of heat relevant to turbine and steam generator system.

In the various embodiments of the present invention, the method can start with combustion reactions, and this combustion reactions is used for another system energy supply that maybe heat generated by combustion reactions and/or pressure can be changed into the power of another form to turbine, oil engine.Fuel for combustion reactions can comprise or hydrogen, hydrocarbon and/or oxidable (burning) be with other carbon compound any released energy.Except fuel only hydrogen time except, the composition from the exhaust of combustion reactions can have the CO of the certain limit depending on reaction property ₂content (such as at least about 2 volume % to about 25 volume % or lower).Therefore, be in some embodiment of carbonaceous fuel at fuel, the CO of exhaust ₂content can be at least about 2 volume %, such as at least about 4 volume %, at least about 5 volume %, at least about 6 volume %, at least about 8 volume % or at least about 10 volume %.In such carbonaceous fuel embodiment in addition or or, CO ₂content can be about 25 volume % or lower, such as about 20 volume % or lower, about 15 volume % or lower, about 10 volume % or lower, about 7 volume % or lower or about 5 volume % or lower.There is lower relative CO ₂the exhaust (for carbonaceous fuel) of content can be equivalent to the exhaust of the combustion reactions of fuel under lean-burn (excess air) using Sweet natural gas and so on.Relative CO ₂the exhaust (for carbonaceous fuel) that content is higher may correspond to the combustion of natural gas reaction in optimizing, as those under exhaust gas recirculatioon, and/or the burning of the class A fuel A of coal.

In some aspects of the invention, for combustion reactions fuel can containing at least about 90 volume % such as, containing 5 or less carbon compounds, at least about 95 volume %.In in such, the CO of this exhaust ₂content can be at least about 4 volume %, such as at least about 5 volume %, at least about 6 volume %, at least about 7 volume % or at least about 7.5 volume %.In addition or or, the CO of this exhaust ₂content can be about 13 volume % or lower, such as about 12 volume % or lower, about 10 volume % or lower, about 9 volume % or lower, about 8 volume % or lower, about 7 volume % or lower, or about 6 volume % or lower.The CO of this exhaust ₂content can represent the numerical range of the configuration depending on burning energy supply generator.The recirculation of exhaust can be of value to the CO of at least about 6 volume % of realization ₂content, and hydrogen is added in combustion reactions and can make CO ₂content improves the CO realizing at least about 7.5 volume % further ₂content.

standby arrangement – high strength NOx turbine

The operation of internal combustion turbine can limit by some questions.Typical case's restriction can be the maximum temperature in combustion zone can be controlled to realize enough low oxynitride (NOx) concentration below certain limit, thus meets supervision emission limit.When making burning and gas-exhausting be discharged in environment, supervision emission limit can require that burning and gas-exhausting has about 20vppm or lower, the NOx content of possible 10vppm or lower.

NOx in the combustion gas turbine of gas-firing is formed can be different with temperature and the residence time.That the reaction causing NOx to be formed has reduction below the flame temperature of about 1500 ℉ and/or minimum importance, but be increased to exceed this point along with temperature, NOx produces can be increased fast.In the gas turbine, initial fuel product can be mixed with additional air with this mixture is cooled to about 1200 ℉ temperature and by the metallurgy limit temperature of decompressor blade.Early stage internal combustion turbine usually have temperature far more than the diffusion flame in the stoichiometry district of 1500 ℉ in implement burning, cause higher NOx concentration.Recently, this generation " dry low NOx " (DLN) burner can use special premixed burner gas-firing under colder lean-burn (fuel fewer than stoichiometric quantity) condition at present.Such as, can more diluent air be mixed in initial flame, can be mixed into less to make temperature drop to ~ 1200 ℉ turboexpander inlet temperature after a while.The shortcoming of DLN burner can comprise bad performance, high maintenance, narrow operating range and difference fuel flexibility when falling combustion (turndown).The latter may pay close attention to, because DLN burner can the more difficult fuel for varying quality (or being difficult to liquid fuel) at all.For low BTU fuel, as containing high CO ₂the fuel of content, does not usually use DLN burner but can use diffusion burner.In addition, higher turboexpander inlet temperature can be used to improve gas turbine proficiency.But the limited and this amount of the amount due to diluent air can improve with turboexpander inlet temperature and reduce, and along with the efficiency improvement of internal combustion turbine, DLN burner can become and not too effectively keep low NOx.

Of the present invention various in, the system that internal combustion turbine is integrated with being used for fuel cell that carbon traps allows to use higher combustion zone temperature, reduce simultaneously and/or extra NOx emission is minimized, and saving by the NOx used at present and the inconsistent turbine fuel of DLN burner realizes similar DLN.In in such, turbine can export cause the higher-wattage of higher NOx emission (i.e. comparatively high temps) and higher-wattage and may run under greater efficiency.In some aspects of the invention, the NOx amount in burning and gas-exhausting can be at least about 20vppm, as at least about 30vppm, or at least about 40vppm.In addition or or, the NOx amount in burning and gas-exhausting can be about 1000vppm or lower, as about 500vppm or lower, or about 250vppm or lower, or about 150vppm or lower, or about 100vppm or lower.In order to NOx level being down to the level of regulatory requirement, the NOx produced balances by destroying (NOx level being down to the equilibrium level in exhaust stream) through the hot NOx of one of several mechanism, and described mechanism is such as the simple heat collapse in gas phase; By the destruction of the nickel cathode catalyst in fuel cell array; And/or the auxiliary heat by injection a small amount of ammonia, urea or other reductive agent before fuel cell destroys.This assists by the hydrogen introduced derived from anode exhaust.Destroy the further reduction of the NOx realized in the negative electrode of fuel cell by electrochemistry, wherein NOx also can be able to be destroyed in cathode surface reaction.This can cause some nitrogen to pass film electrolyte transport to anode, can form the nitrogen compound of ammonia or other reduction this its.With regard to the NOx minimizing method relating to MCFC, the expection NOx minimizing from fuel cell/fuel cell array can be about 80% or lower of the NOx in the input of fuel battery negative pole, as about 70% or lower, and/or at least about 5%.Point out, sulfide corrosion also can limit temperature affect turbine vane metallurgy in conventional systems.But the sulphur restriction of MCFC system can require the fuel sulfur content reduced usually, and this reduces or reduces the problem relevant with sulfide corrosion to greatest extent.Under low fuel utilization ratio, run MCFC array can alleviate these problems further, as be equivalent at a part of fuel for combustion reactions from anode exhaust hydrogen in.

fuel cell operation at lower voltages

Conventional fuel cell practice teaches fused carbonate and Solid Oxide Fuel Cell and should move to power density is maximized.Make the maximized ability of power density can be subject to meeting other demand restriction running constraint condition (as striding across the temperature difference of fuel cell).Usually, select fuel cell parameters with optimizing power density as wide as possible under the prerequisite considering other constraint condition.Such as, NETLFuelCellHandbook Fig. 6-13 and around the discussion of Fig. 6-13 teach when fuel availability reduces occur fuel conversion reduce hinder fuel cell operation under low fuel utilization ratio.Usually, comparatively high working voltage V is needed _ato improve power density.

One aspect of the present invention can be under low fuel utilization ratio fuel cell operation and by reduce voltage overcome CH ₄the problem that transformation efficiency reduces.The voltage reduced can improve the heat being available for conversion reaction.In in various, fuel cell can be less than about 0.7 volt, the voltage V of the about 0.66V or about 0.65V or lower that is such as less than about 0.68V, is less than about 0.67V, is less than _alower operation.In addition or or, fuel cell can at least about 0.60, such as at least about voltage V of 0.61, at least about 0.62 or at least about 0.63 _alower operation.In this case, along with loss of voltage, the energy that originally can leave fuel cell as electric energy under high voltages can be used as heat and stays in battery.This heat additionally can allow the thermo-negative reaction increased to occur, such as, improve CH ₄change into the transformation efficiency of synthetic gas.

Carry out a series of simulation to illustrate the benefit running molten carbonate fuel cell according to the present invention.Specifically, the benefit through different fuel availabilitys fuel cell operation is at the lower voltage carried out simulating illustrating.Under low voltage and low fuel utilization ratio, the impact of fuel cell operation is presented in Figure 15 and 16.Figure 15 illustrates a model of fuel cell with the representation that the Fig. 6-13 with NETLFuelCellHandbook is similar.For generation of the simulation of result shown in Figure 15 at constant CH ₄run under flow velocity.Figure 15 shows the transformation efficiency 1520 that can occur under different fuel utilization ratio 1510 per-cent under different operating voltage.High-voltage (0.8V) 1550 times, along with fuel availability reduces, CH ₄transformation efficiency also shows and is down to low-level.Along with loss of voltage (to 0.7V, 1540 and 0.6V, 1530), the CH under each fuel availability point of modeling ₄transformation efficiency shows higher than the corresponding transformation efficiency under 0.8V.Although Figure 15 shows CH ₄transformation efficiency only improves several per-cent, but as shown in Figure 16, this impact in fact can be quite remarkable.

Simulation for generation of result shown in Figure 16 is not at CH ₄constant flow rate under carry out, but to carry out under constant fuel cell area.In figure 16, not with CH ₄based on conversion percentages but with the CH under available fuel cell area ₄the identical operation of fuel cell is illustrated based on absolute flow velocity.X-axis 1610 shows fuel availability and y-axis 1620 shows stdn CH ₄transformation efficiency.The analog result that curve 1630 produces under being presented at 0.6V.The analog result that curve 1640 produces under being presented at 0.7V.The analog result that curve 1650 produces under being presented at 0.8V.For the data shown in Figure 15 and 16, along with fuel availability reduces, especially along with loss of voltage, current density shows raising and is greater than 5 times.Therefore, with of the present invention in improve power density by reducing operating voltage under consistent operational conditions.The power density improved and low voltage seem to be different from the impact realized in traditional operational process, and wherein lower operating voltage causes lower-wattage density usually.As shown in Figure 16, to total CH ₄it is significant that the impact of transformation efficiency shows: when reducing voltage, under compared with low fuel utilization ratio, realize much higher CH ₄transformation efficiency, it records as absolute flow velocity.

Additional embodiment

Embodiment 1. 1 kinds of methods from Combustion Source capturing carbon dioxide, the method comprises: by combustion fuel stream with containing O ₂combustion zone introduced by stream; Carry out combustion reactions in combustion zone and produce burning and gas-exhausting, burning and gas-exhausting comprises CO ₂; Use the fuel cell array processing cathode inlet stream of one or more molten carbonate fuel cell, this cathode inlet stream comprises at least first part of burning and gas-exhausting, cathode exhaust gas stream is formed by least one cathode outlet of fuel cell array, described one or more molten carbonate fuel cell comprises one or more anode of fuel cell and one or more fuel battery negative pole, and described one or more molten carbonate fuel cell and combustion zone are operated by least one cathode inlet and be connected; Make the carbonate from described one or more fuel battery negative pole and H ₂in described one or more anode of fuel cell, reaction produces the anode exhaust stream of electricity and at least one anode export from fuel cell array, and this anode exhaust stream comprises CO ₂and H ₂; By anode exhaust stream separation of C O in one or more segregation section ₂, form poor CO ₂anode exhaust stream; With by described poor CO ₂at least burns recirculated part of anode exhaust stream be sent to combustion zone.

The method of embodiment 2. embodiment 1, it comprises further by described poor CO ₂the anode recirculation part of anode exhaust stream be recycled to described one or more anode of fuel cell.

The method of embodiment 3. embodiment 2, it comprises further carbonaceous fuel is passed into described one or more anode of fuel cell, and this carbonaceous fuel optionally comprises CH ₄.

The method of embodiment 4. embodiment 3, wherein passes into described one or more anode of fuel cell and comprises by carbonaceous fuel: the reformation at least partially of carbonaceous fuel is produced H ₂; And the H that will produce ₂pass into described one or more anode of fuel cell at least partially.

The method of embodiment 5. embodiment 3, wherein passes into described one or more anode of fuel cell by described carbonaceous fuel, before entering described one or more anode of fuel cell, described carbonaceous fuel is not sent into reforming sections.

Method any one of the above-mentioned embodiment of embodiment 6., wherein said burning and gas-exhausting comprises the CO of about 10 volume % or lower ₂(the such as CO of 8 volume % ₂), described burning and gas-exhausting optionally comprises the CO of at least about 4 volume % ₂.

Method any one of the above-mentioned embodiment of embodiment 7., it comprises further the second section of described burning and gas-exhausting is recycled to combustion zone, and this second section of described burning and gas-exhausting optionally comprises at least about 6 volume %CO ₂.

The method of embodiment 8. embodiment 7, is wherein recycled to combustion zone by the second section of described burning and gas-exhausting and comprises: at the second section of described burning and gas-exhausting and containing H ₂between O stream, exchanging heat forms steam; By this second section Separation of Water of described burning and gas-exhausting, form poor H ₂the burning and gas-exhausting stream of O; And by described poor H ₂the burning and gas-exhausting stream of O pass into combustion zone at least partially.

Method any one of the above-mentioned embodiment of embodiment 9., wherein in one or more segregation section by described anode exhaust stream separation of C O ₂before, described anode exhaust stream comprises the hydrogen (such as at least about 10 volume % or at least about 15 volume %) of at least about 5.0 volume %.

Method any one of the above-mentioned embodiment of embodiment 10., it is included in one or more segregation section further by described anode exhaust stream separation of C O ₂before, described anode exhaust stream is exposed to water gas converting catalyst, forms the anode exhaust stream through conversion, through the H of the anode exhaust stream of conversion ₂content is greater than the H of the anode exhaust stream before being exposed to water gas converting catalyst ₂content.

Method any one of the above-mentioned embodiment of embodiment 11., the fuel availability of wherein said one or more anode of fuel cell is about 45% to about 65% (as about 60% or lower).

Method any one of the above-mentioned embodiment of embodiment 12., wherein by described poor CO ₂the described burns recirculated part of anode exhaust stream pass into combustion zone before, by described poor CO ₂the described burns recirculated part of anode exhaust stream and combustion fuel stream merge.

Method any one of the above-mentioned embodiment of embodiment 13., wherein cathode exhaust gas stream has the CO of about 2.0 volume % or lower (such as about 1.5 volume % or lower or about 1.2 volume % or lower) ₂content.

Method any one of the above-mentioned embodiment of embodiment 14., wherein in one or more segregation section by described anode exhaust stream separation of C O ₂comprise the described anode exhaust stream of cooling, form the CO of condensation ₂phase.

The method of embodiment 15. embodiment 14, wherein in one or more segregation section by described anode exhaust stream separation of C O ₂be included in the CO forming condensation further ₂mutually from described anode exhaust stream Separation of Water.

The system of embodiment 16. for generating electricity, comprise: the combustion turbine comprising compressor, described compressor receives oxygenant input and is communicated with combustion zone fluid, described combustion zone receives the input of at least one combustion fuel further, and described combustion zone is vented the decompressor fluid exported and is communicated with having; Exhaust gas recycling system, which provides the first part exported at described expander exhaust gas and is communicated with the fluid between combustion zone; Molten carbonate fuel cell array, it comprises one or more anode of fuel cell and one or more fuel battery negative pole, this molten carbonate fuel cell array has the input of at least one negative electrode, at least one negative electrode exports, at least one anode inputs and at least one anode exports, and the second section that described expander exhaust gas exports is communicated with at least one negative electrode input fluid described; Anode recirculation loop, it comprises one or more carbon dioxide separation section and exports to form anode recirculation loop for separating of anode exhaust stream, and the first part that anode recirculation loop exports is supplied to combustion zone as combustion fuel input.

The system of embodiment 17. embodiment 16, is wherein supplied to described at least one anode input by the second section that described anode recirculation loop exports.

The system of embodiment 18. embodiment 16 or 17, wherein said anode recirculation loop also comprises water gas shift reaction section, described anode exhaust stream before at least one section of described one or more carbon dioxide separation section by described water gas shift reaction section.

System any one of embodiment 19. embodiment 16-18, wherein said exhaust gas recycling system also comprises heat recovery steam generation systems.

System any one of embodiment 20. embodiment 16-19, wherein said exhaust gas recycling system passes into compressor by the described first part exported by described expander exhaust gas and provides the first part exported at described expander exhaust gas and be communicated with the fluid between combustion zone.

Embodiment

Carry out a series of simulation to confirm for fuel cell separation of C O ₂use the benefit of the configuration improved.These simulations are based on the empirical model of the various parts in power generation system.These simulations are based on the steady state conditions considered according to mass balance and energy balance in Analytical system.

For the combustion reactions of turbine, this model comprises each fuel element in the charging of combustion zone (as C ₁-C ₄hydrocarbon, H ₂and/or CO) expection ignition energy value and expection products of combustion.This is for measuring burning and gas-exhausting composition.Initial reformate district before anode utilizes " idealized " reforming reaction to run with by CH ₄change into H ₂.Anodic reaction modeling to reform further during anode operation.Point out, the empirical model of this anode does not require the initial H in anode ₂concentration is to reform in the anode.Anode and cathodic reaction are all modeled as and expection input are changed into expection output under the utilization ratios selected as mode input.The model of initial reformate district and anode/cathode reaction comprises the expection thermal energy carried out needed for this reaction.This model also measures based on the amount of the reactant consumed in a fuel cell and the utilization ratio of reactant the electric current produced according to Nernst equation.For input combustion zone or the thing class not participating in the reaction in model assembly directly of anode/cathode fuel cell, these thing classes as exhaust or the part that exports through model district.

Except chemical reaction, the parts of this system also have hot I/O value and the efficiency of expection.Such as, cryogenic separator has based on isolated CO ₂and H ₂o volume and the energy that needs, and the energy needed based on compression and the gas volume stayed in anode output stream.Also measure the expection energy expenditure being used for water gas shift reaction district (if existence) and the compression for exhaust gas recirculation.Also use the expection generating efficiency based on the steam generated by heat exchange in the model.

Configurations for simulating comprises internal combustion turbine combination, and it comprises compressor, combustion zone and decompressor, is similar to the configuration in Fig. 8.In this configurations, gas fuel is provided to input 812 to combustion zone 815.The input of this Sweet natural gas comprises ~ 93%CH ₄, ~ 2%C ₂h ₆, ~ 2%CO ₂with ~ 3%N ₂.The oxidant feed 811 of compressor 802 has the representativeness composition of air, comprises about 70%N ₂with about 18%O ₂.After decompressor 806, make a part of burning and gas-exhausting 892 through heat recovery steam generation systems 890, and then be recycled to compressor 802.All the other burning and gas-exhaustings 822 are sent into fuel battery negative pole.After fuel battery negative pole, cathode exhaust gas 824 leaves this system.Unless specifically stated so, the burning and gas-exhausting part 892 of combustion zone is returned in recirculation is ~ 35%.This recycling part of burning and gas-exhausting contributes to the CO improving combustion zone output ₂content.Due to select fuel cell area with by negative electrode export in CO ₂concentration is down to ~ fixed value of 1.45%, find that the recirculation of burning and gas-exhausting improves CO ₂collection efficiency.

In this configurations, fuel cell is as the single fuel cell modeling with the size being applicable to processing burning and gas-exhausting.Carry out this modeling to represent the corresponding multiple fuel cells (fuel cell pack) be arranged in parallel using and there is the active area identical with model battery.Unless specifically stated so, the fuel availability in the anode of fuel cell is set as ~ 75%.Fuel cell area is variable, so that selected fuel availability causes the constant fuel cell voltage of fuel cell at ~ 0.7 volt and the constant CO of ~ 1.45 volume % ₂run under negative electrode output/exhaust concentration.

In this configurations, anode fuel inlet flow provides Sweet natural gas as above to form as anode feed.Also exist steam providing ~ the input fuel of 2:1 in vapor carbon ratio.Optionally, the input of this Sweet natural gas can be carried out reforming with by a part of CH in Sweet natural gas before entering anode ₄change into H ₂.When exist in advance reforming sections time, can reform before entering anode ~ 20% CH ₄to generate H ₂.Anode is exported by cryogenic separator, to remove H ₂o and CO ₂.After being separated, remaining anode output is processed according to the configuration of each embodiment.

For given configuration, various value can be calculated in the steady state.For fuel cell, measure the CO in anode exhaust ₂amount and cathode exhaust gas in O ₂amount.In each calculating, the voltage of fuel cell is fixed as ~ 0.7V.For the condition that can cause higher peak voltage, be exchange with extra current, progressively reduction voltage is beneficial to the comparison between simulation.Also the final cathode exhaust gas CO of realization ~ 1.45 volume % is measured ₂fuel cell area needed for concentration is to measure the current density of every fuel cell area.

Another class value and CO ₂discharge relevant.Based on the total CO generated ₂to the CO through cryogenic separator trapping and removing ₂amount (million tons/year) measures the CO trapped by this system ₂per-cent.The CO do not trapped ₂be equivalent to the CO of the part " loss " as cathode exhaust gas ₂.Based on the CO of trapping ₂amount, also can measure trapping CO per ton ₂required fuel cell area.

Other value measured in this simulation comprises relative to the carbon amounts in anode feed and N ₂amount, the H in anode feed ₂amount.Point out, desired by typical actual natural gas charging, the Sweet natural gas for combustion zone and anode feed comprises a part of N ₂.Therefore, N ₂be present in anode feed.Also be determined as and reform and heat heat needed for anode feed (or equivalently, steam) amount.Based on the Power penalty that the compression in low temperature separation process section is similar with the power measurement needed for being separated.For wherein by the configuration of a part of anode off-gas recirculation to combustion turbine, also measure and correspond to H ₂turbine fuel per-cent.Based on the operation of this turbine, fuel cell and the excess steam of generation and in order to heated reformate district, compression and/or any power of being separated and consuming, measure total pure horsepower of this system so that based on the clean electrical efficiency of flow measurement of Sweet natural gas (or other fuel) of charging being used as this turbine and anode.

The result of the simulation that Figure 10 and 11 display is carried out based on several configuration variants.What Figure 10 display was corresponding with configurations is configured to and wherein a part of anode is exported several configurations that 835 are recycled to anode input 845.In Fig. 10, the first configuration (1a) sends into the burner after being positioned at turbine combustion district based on being exported by anode remaining after carbonic acid gas and water segregation section.This is provided for the heat of reforming reaction, also for negative electrode input provides extra carbonic acid gas.Configuration 1a represents legacy system, Manzolini reference As mentioned above, and just Manzolini reference does not describe the recirculation of exhaust.Anode is used to export 835 CO causing for being exported by negative electrode as the charging of burner ₂content is down to ~ and the predict fuel cell area of 1.45 volume % is ~ 208km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 111lbsCO ₂/ MWhr.Due to trapping CO ₂required large fuel cell area, the pure horsepower of generation is ~ 724MW/ hour.Based on these values, the CO of trapping fixed amount can be calculated ₂required fuel cell area amount, as trapped megaton CO at 1 year run duration ₂required fuel cell area.For configuration 1a, required fuel cell area is ~ 101.4km ²* year/megaton-CO ₂.Be ~ 58.9% relative to the electric power luminous efficiency of the energy content of all fuel used in power generation system.By comparing, the electrical efficiency of the turbine trapped without any type of carbon is ~ 61.1%.

In the second group configuration (2a – 2e), anode is exported 835 and be recycled to anode input 845.Configuration 2a represents anode and exports the basic recirculation of arriving anode input after isolation.Configuration 2b is included in the water gas shift reaction district 870 before carbon dioxide separation section.Configuration 2c is not included in the reforming sections before anode input.Configuration 2d comprise reforming sections, but with ~ 50% but not the fuel availability of ~ 75% run.Configuration 2e runs with the fuel availability of ~ 50% and does not have the reforming sections before anode.

As configured as shown in 2a, anode is exported recirculation get back to anode input cause required fuel cell area to be down to ~ 161km ².But, from the CO of cathode exhaust gas ₂loss is increased to ~ 123lbsCO ₂/ MWhr.This does not add extra CO owing to by the burning in the burner of anode exhaust after turbine in negative electrode input ₂this is true.On the contrary, the CO of negative electrode input ₂content is only based on the CO of combustion zone ₂export.Net result in configuration 2a is ~ 87.5km ²* year/megaton-CO ₂trapping CO per ton ₂comparatively low fuel cell area, but slightly high CO ₂quantity discharged.Due to the fuel cell area reduced, the total power of generation is ~ 661MW.Although the pure horsepower produced in configuration 2a is lower by about 10% than the pure horsepower in configuration 1a, fuel cell area reduction is greater than 20%.Electrical efficiency is ~ 58.9%.

In configuration 2b, the hydrogen content being sent to anode is improved in additional water gas shift reaction district, and this reduces the fuel quantity needed for anodic reaction.Comprising water gas shift reaction district at configuration 2b causes required fuel cell area to be down to ~ 152km ².From the CO of cathode exhaust gas ₂loss is ~ 123lbsCO ₂/ MWhr.Trap every megaton CO ₂fuel cell area be ~ 82.4km ²* year/megaton-CO ₂.The total power produced is ~ 664MW.Electrical efficiency is ~ 59.1%.

Configuration 2c utilizes the hydrogen content in anode recirculation further by eliminating the fuel reforming that occurs before entering anode.In configuration 2c, still can reform in anode itself.But be different from the legacy system in conjunction with independent reforming sections before entering anode of fuel cell, the hydrogen content that configuration 2c relies on recycled anode gas is provided for maintaining the most low hydrogen air content of anodic reaction.Owing to not needing independent reforming sections, do not consume heat energy to keep the temperature of reforming sections.Configuration 2c causes required fuel cell area to be down to ~ 149km ².From the CO of cathode exhaust gas ₂loss is ~ 122lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 80.8km ²* year/megaton-CO ₂.The total power produced is ~ 676MW.Electrical efficiency is ~ 60.2%.Based on analog result, eliminate reforming step and seem that minimal effect is only had to required fuel cell area, but electrical efficiency shows and improves about 1% with configuring compared with 2b.For plant-scale power station, even only the efficiency improvement of 1% is also considered to represent generating advantage huge during a year.

In configuration 2d, still carry out reforming before entering anode with the methane by input anode ~ 20% change into H ₂.But, by the fuel availability in anode from ~ 75% being down to ~ 50%.This causes required fuel cell area to be significantly down to ~ 113km ².From the CO of cathode exhaust gas ₂loss is ~ 123lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 61.3km ²* year/megaton-CO ₂.The total power produced is ~ 660MW.Electrical efficiency is ~ 58.8%.Based on analog result, reduce the remarkable reduction that fuel availability provides fuel cell area.In addition, compare with configuration 2b with 2e, configuration 2d is provided for realizing required CO unexpectedly ₂remove the minimum fuel cell area of level.

Configuration 2e combines ~ fuel availability of the reduction of 50% and the reforming sections before eliminating anode inlet.This configuration provides the combination of the electrical efficiency of improvement and the fuel cell area of reduction.But fuel cell area is slightly larger than fuel cell area required in configuration 2d.This is surprising, because reduce fuel cell area in the reforming sections before eliminating anode inlet in configuration 2c compared with configuration 2b.Based on this, originally estimate that configuration 2e can provide and the further reduction configuring fuel cell area compared with 2d.In configuration 2e, from the CO of cathode exhaust gas ₂loss is ~ 124lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 65.0km ²* year/megaton-CO ₂.The total power produced is ~ 672MW.Electrical efficiency is ~ 59.8%.Point out, configuration 2d produces only than the power of configuration 2e low 2%, and configures the fuel cell area ratio configuration 2e low at least 6% of 2d.

Figure 11 shows the analog result of configuration in addition, and these configure in addition and comprise near few a part of anode off-gas recirculation to the combustion zone for turbine.In fig. 11, configuration 1b is similar to (in Fig. 10) configuration 1a, but be also included in CO ₂water gas shift reaction section before segregation section.Therefore, configuration 1b represents legacy system, Manzolini reference As mentioned above, and just Manzolini reference does not describe the recirculation of water gas shift reaction section or exhaust.Realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 190km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 117lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 97.6km ²* year/megaton-CO ₂.The total power produced is ~ 702MW.Electrical efficiency is ~ 59.1%.

Configuration 3a, 3b and 3d correspond to the configuration that its Anodic exports the input of the combustion zone being used as turbine.In such arrangements, the H of anode output ₂content is effective to the fuel be used as in turbine combustion district.This shows is favourable, because for generation of H ₂carbonaceous fuel produce in anode recirculation loop, wherein most of gained CO ₂can remove via low temperature separation process section.This also can cause the carbonaceous fuel amount being delivered to fuel section to reduce, but the CO during the minimizing of carbonaceous fuel also can cause negative electrode to input in combustion zone ₂concentration reduces.

Configuration 3a is the configuration being similar to configuration 1a, but has the recirculation of anode exhaust to combustion zone.Realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 186km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 114lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 100.3km ²* year/megaton-CO ₂.The total power produced is ~ 668MW.Electrical efficiency is ~ 59.7%.Relative to configuration 1a, configuration 3a has lower total CO ₂generation (configuration 1a ~ 2.05 million tons/year of vs. configuration 3a ~ 1.85 million tons/year).This is presumably because that the amount of the carbonaceous fuel being delivered to combustion zone reduces.But this also shows the CO being delivered to negative electrode input causing reducing ₂concentration, this CO causing models show to reduce for configuration 3a ₂removal efficiency.Therefore, the CO left in cathode exhaust gas ₂net amount is suitable for configuration 1a and configuration 3a.But configuration 3a shows has several advantage relative to configuration 1a.First, configuration 3a requires lower fuel cell area, and therefore the system configured in 3a can have the cost of reduction.In addition, the system table in configuration 3a reveals the electrical efficiency with improvement, and this can show that less fuel uses, even after adjusting the different capacity output of configuration.

Configuration 3b is similar to configuration 3a, but is also included in the water gas shift reaction district before low temperature separation process section.Realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 173km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 124lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 96.1km ²* year/megaton CO ₂.The total power produced is ~ 658MW.Electrical efficiency is ~ 59.8%.Configuration 3b shows the CO via cathode exhaust gas with increase ₂discharge.This is presumably because the added hydrogen being delivered to combustion zone, this can cause the CO of the burning and gas-exhausting for negative electrode input ₂the corresponding reduction of amount.But fuel cell area reduces further.

Configuration 3d is similar to configuration 3b, but anode fuel utilization ratio by ~ 75% being reduced to ~ 50%.Realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 132km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 128lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 77.4km ²* year/megaton-CO ₂.The total power produced is ~ 638MW.Electrical efficiency is ~ 60.7%.Based on analog result, the fuel availability reduced in anode shows the remarkable improvement of the electrical efficiency caused relative to configuration 3b.This is presumably because the added hydrogen of the combustion zone being delivered to turbine.As a comparison, be ~ 61.1% without any the electrical efficiency of the turbine of carbon trapping.Therefore, anode off-gas recirculation is revealed to combustion zone and the more associative list of low fuel utilization ratio allow to obtain the electrical efficiency close to the efficiency under carbon-free trapping system.

Configuration 4d with 4e represents such configuration: wherein will be separated (removing) CO ₂and H ₂after O remaining anode exhaust the recirculation inputted to anode and to the combustion zone of turbine recirculation between even partition.In order to anode input and combustion zone all provide enough hydrogen, the anode fuel utilization ratio in configuration 4d and 4e is set to ~ 50%.Configure the water gas shift reaction district before 4d and 4e is included in segregation section.Configuration 4d comprises independent reforming sections, with by the input of the described additional fuel of anode ~ 20% to reform before fuel enters anode.Configuration 4e enters the reforming sections before anode input not included in fuel.

Configuration 4d shows and presents the benefit of anode off-gas recirculation to both anode input and combustion zone.Relative to configuration 2d, configuration 4d shows the electrical efficiency providing high approximately whole one percentage point (aboutafullpercentagepointgreater).Relative to configuration 3d, configuration 4d provides the fuel cell area of reduction.In configuration 4d, realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 122km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 126lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 63.4km ²* year/megaton-CO ₂.The total power produced is ~ 650MW.Electrical efficiency is ~ 59.9%.

In configuration 4e, remove pre-reforming segment table reveal further benefit is provided.Realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 112km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 126lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 63.4km ²* year/megaton-CO ₂.The total power produced is ~ 665MW.Electrical efficiency is ~ 61.4%.It is to be noted, in fact electrical efficiency is greater than the efficiency (~ 61.1%) of the turbine do not trapped containing the carbon of any type.

Figure 12 display is from the result of the simulation carried out based on several configuration variant and alternative operational conditions.The factor more than the simulation explained with reference to Figure 10 is considered in the simulation of Figure 12 above.In other side, the analogy shown in Figure 12, in the simulation shown in Figure 10, wherein adds minority variation.Such as, except about 0.7 volt used in Figure 10 simulation, each situation is also at about 0.65 volt of Imitating.In addition, in each configuration, also add the situation with 0%EGR.What Figure 12 display was corresponding with configurations is configured to and wherein a part of anode is exported several configurations being recycled to anode input.Unless indicated, for the analog result shown in Figure 10, exhaust gas recirculatioon is about 35%.In fig. 12, each configuration runs as shown under ~ 35% or 0%EGR.

Except different configurations and alternative operational conditions, Figure 12 shows other parameters do not shown in Figure 10.Such as, Figure 12 comprises approximate fuel availability, approximate vapor carbon ratio, EGR recirculation %, no matter whether there is water-gas shift in the configuration to process the approximate CO in anode exhaust, approximate inside reforming %, cathode inlet ₂approximate O in concentration and cathode exhaust gas ₂content.

In fig. 12, the first configuration (0) shown in row 1204 sends into the burner after being positioned at turbine combustion district based on being exported by anode remaining after carbonic acid gas and water segregation section.This is provided for the heat of reforming reaction, also for negative electrode input provides extra carbonic acid gas.Configuration 0 does not comprise EGR.Configuration 0 be provided for do not comprise EGR other simulate the useful base case compared.Configuration 0 represents legacy system, Manzolini reference As mentioned above.Anode is used to export the CO causing for being exported by negative electrode as the charging of burner ₂content is down to ~ and the predict fuel cell area of 1.5 volume % is ~ 185km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 212lbsCO ₂/ MWhr.Due to trapping CO ₂required large fuel cell area, the pure horsepower of generation is ~ 679MW/ hour.Based on these values, the CO of trapping fixed amount can be calculated ₂required fuel cell area amount, as trapped megaton CO at 1 year run duration ₂required fuel cell area.For configuration 0, the fuel cell area trapped needed for a megaton is ~ 113.9km ²* year/megaton-CO ₂.Be ~ 57.6% relative to the electric power luminous efficiency of the energy content of all fuel used in power generation system.

In fig. 12, the second configurations (1a) shown in row 1206 sends into the burner after being positioned at turbine combustion district based on being exported by anode remaining after carbonic acid gas and water segregation section.This is provided for the heat of reforming reaction, also for negative electrode input provides extra carbonic acid gas.Configuration 1a represents legacy system, Manzolini reference As mentioned above, and just Manzolini reference does not describe the recirculation of exhaust.Anode is used to export the CO causing for being exported by negative electrode as the charging of burner ₂content is down to ~ and the predict fuel cell area of 1.5 volume % is ~ 215km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 148lbsCO ₂/ MWhr.Due to trapping CO ₂required large fuel cell area, the pure horsepower of generation is ~ 611MW/ hour.Based on these values, the CO of trapping fixed amount can be calculated ₂required fuel cell area amount, as trapped megaton CO at 1 year run duration ₂required fuel cell area.For configuration 1a, the fuel cell area trapped needed for a megaton is ~ 114.2km ²* year/megaton-CO ₂.Be ~ 51.2% relative to the electric power luminous efficiency of the energy content of all fuel used in power generation system.Can by base case 1a compared with base case 0 to show the result of the exhaust gas recirculatioon increasing ~ 35%.

In fig. 12, the 3rd configurations (1b) shown in row 1208 sends into the burner after being positioned at turbine combustion district based on being exported by anode remaining after carbonic acid gas and water segregation section.This is provided for the heat of reforming reaction, also for negative electrode input provides extra carbonic acid gas.Water-gas shift before base case 1b is included in carbonic acid gas and water segregation section is to process anode exhaust.Configuration 1b represents legacy system, Manzolini reference As mentioned above, and just Manzolini reference does not describe recirculation or the water-gas shift of exhaust.Anode is used to export the CO causing for being exported by negative electrode as the charging of burner ₂content is down to ~ and the predict fuel cell area of 1.5 volume % is ~ 197km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 147.5lbsCO ₂/ MWhr.Due to trapping CO ₂required large fuel cell area, the pure horsepower of generation is ~ 609MW/ hour.Based on these values, the CO of trapping fixed amount can be calculated ₂required fuel cell area amount, as trapped megaton CO at 1 year run duration ₂required fuel cell area.For configuration 1b, the fuel cell area trapped needed for a megaton is ~ 107.6km ²* year/megaton-CO ₂.Be ~ 52.1% relative to the electric power luminous efficiency of the energy content of all fuel used in power generation system.Can by base case 1b compared with base case 1a to show the result increasing water-gas shift.Can by base case 1b compared with base case 0 to show the result of exhaust gas recirculatioon increasing water-gas shift and ~ 35%.

In the second group configuration (2a – 2e), anode is exported and is recycled to anode input.Configuration 2a represents anode and exports after water and carbon dioxide separation to the basic recirculation that anode inputs.Configuration 2b is included in the water gas shift reaction district before carbon dioxide separation section.Configuration 2c is not included in the reforming sections before anode input.Configuration 2d comprise reforming sections, but with ~ 50% but not the fuel availability of ~ 75% run.Configuration 2e runs with the fuel availability of ~ 50% and does not have the reforming sections before anode.Configuration 2g comprises reforming sections and is similar to configuration 2b and 2d, but runs with the fuel availability of ~ 30%.

Simulate three kinds of changes to 2a configuration.2a analog result shown in row 1210 is based on the configuration comprising EGR, and the analog result shown in row 1212 is based on the configuration not comprising EGR.Analog result shown in row 1212 is based on not comprising EGR and keeping the configuration of the operating voltage of about 0.65.In the simulation of row 1210 and 1212, keep the operating voltage of about 0.65.

As shown in 2a, anode to be exported recirculation to get back to anode input cause required fuel cell area compared with relevant rudimentary situation to reduce as configured.In row 1210, required fuel cell area is ~ 174km ², in row 1212, required fuel cell area is ~ 169km ², and required fuel cell area is ~ 131km in row 1210 ².Can find out, the voltage of reduction causes lower fuel cell area.

2a configuration change is from the CO of cathode exhaust gas ₂discharge.CO in row 1210 ₂discharge is ~ 141lbsCO ₂/ MWhr, CO in row 1212 ₂discharge is ~ 217.9lbsCO ₂/ MWhr, in row 1214, CO ₂discharge is ~ 141lbsCO ₂/ MWhr.

Configuration 2b in, except anhydrate and carbonic acid gas before comprise water gas shift reaction district to process anode export stream.Simulate three kinds of changes to 2b configuration.2b analog result shown in row 1216 is based on the configuration comprising EGR, and the analog result shown in row 1218 is based on the configuration not comprising EGR.Analog result shown in row 1220 is based on not comprising EGR and keeping the configuration of the operating voltage of about 0.65.In the simulation of row 1216 and 1218, keep the operating voltage of about 0.65.

In configuration 2b, the hydrogen content being sent to anode is improved in additional water gas shift reaction district, and this reduces the fuel quantity needed for anodic reaction.Comprising water gas shift reaction district at configuration 2b causes required fuel cell area to be ~ 168km in row 1216 ², be ~ 164km in row 1218 ²with in row 1220, be ~ 129km ².From the CO of cathode exhaust gas ₂being lost in row 1216 is ~ 143lbsCO ₂/ MWhr, be ~ 217.5lbsCO in row 1218 ₂/ MWhr and be ~ 218.7lbsCO in row 1220 ₂/ MWhr.Trap every megaton CO ₂fuel cell area be ~ 101.1km in row 1216 ²* year/megaton-CO ₂, be ~ 114.9km in row 1218 ²* year/megaton-CO ₂with in row 1220, be ~ 90.1km ²* year/megaton-CO ₂.

Configuration 2c utilizes the hydrogen content in anode recirculation further by eliminating the fuel reforming that occurs before entering anode.In configuration 2c, still can reform in anode itself.But be different from the legacy system in conjunction with independent reforming sections before entering anode of fuel cell, the hydrogen content that configuration 2c relies on recycled anode gas is provided for maintaining the most low hydrogen air content of anodic reaction.Owing to not needing independent reforming sections, do not consume heat energy to keep the temperature of reforming sections.

Simulate four kinds of changes to 2c configuration.2c analog result shown in row 1222 and 1224 is based on the configuration comprising EGR, and the analog result shown in row 1226 and 1228 is based on the configuration not comprising EGR.Analog result shown in row 1222 and 1226 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1224 and 1228 is based on the simulation of operating voltage wherein keeping about 0.65.

Configuration 2c causes required fuel cell area to be ~ 161km for row 1222 ², be ~ 126km for row 1224 ², be ~ 157km for row 1226 ²be ~ 126km for row 1228 ².From the CO of cathode exhaust gas ₂loss is ~ 142.5lbsCO for row 1222 ₂/ MWhr, be ~ 143.5lbsCO for row 1224 ₂/ MWhr, be ~ 223.7lbsCO for row 1226 ₂/ MWhr and be ~ 225.5lbsCO for row 1228 ₂/ MWhr.

In configuration 2d, with the similar layout of configuration 2b in still carry out reforming before entering anode with the methane by inputting anode ~ 20% change into H ₂.Be different from 2b, by the fuel availability in anode from ~ 75% being down to ~ 50%.

Simulate four kinds of changes to 2d configuration.2d analog result shown in row 1230 and 1232 is based on the configuration comprising EGR, and the analog result shown in row 1234 and 1236 is based on the configuration not comprising EGR.Analog result shown in row 1230 and 1234 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1232 and 1236 is based on the simulation of operating voltage wherein keeping about 0.65.

Configuration 2e combine 2d ~ fuel availability of reduction of 50% and the elimination anode inlet of 2c before reforming sections.Simulate four kinds of changes to 2e configuration.2e analog result shown in row 1238 and 1240 is based on the configuration comprising EGR, and the analog result shown in row 1242 and 1244 is based on the configuration not comprising EGR.Analog result shown in row 1238 and 1242 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1240 and 1244 is based on the simulation of operating voltage wherein keeping about 0.65.

In configuration 2g, with the similar layout of configuration 2b and 2d in still carry out reforming before entering anode with the methane by inputting anode ~ 20% change into H ₂.Be different from 2b and 2d, by the fuel availability in anode from ~ 75% or ~ 50% be down to ~ 30%.

Row 1250 describe the result of the simulation carried out with the configuration similar with the configuration shown in Fig. 9.In fig .9, EGR998 first through negative electrode, then through HRSG854.Carry out simulating the base case of this configuration.Analog result from base case is presented in row 1209.Be different from base case, the analog result of row 1250 is based on ~ 50% but not the fuel availability of ~ 75%.In addition, row 1250 analog result based on wherein with the similar layout of configuration 2b and 2d in carry out reforming before entering anode with the methane by inputting anode ~ 20% change into H ₂configuration.

Figure 13 display is from the result of the simulation carried out based on several configuration variant and alternative operational conditions.The factor more than the simulation explained with reference to Figure 11 is considered in the simulation of Figure 13 above.In other side, the analogy shown in Figure 13, in the simulation shown in Figure 11, wherein adds minority variation.Such as, except about 0.7 volt used in Figure 11 simulation, each situation is also at about 0.65 volt of Imitating.In addition, in each configuration, also add the situation with 0%EGR.Figure 13 display corresponds to configurations and wherein a part of anode is exported the configuration of several configurations being recycled to the combustion zone of turbine.Unless indicated, for the analog result shown in Figure 11, exhaust gas recirculatioon is ~ 35%.In fig. 13, each configuration runs as shown under ~ 35% or 0%EGR.

Except different configurations and alternative operational conditions, Figure 13 shows other parameters do not shown in Figure 11.Such as, Figure 13 comprises approximate fuel availability, approximate vapor carbon ratio, EGR%, no matter whether there is water-gas shift in the configuration to process the approximate CO in anode exhaust, approximate inside reforming %, cathode inlet ₂approximate O in concentration and cathode exhaust gas ₂content.

The analog result of Figure 13 display to additional configuration, these additional configuration comprise at least partially anode exhaust to the recirculation in turbine combustion district.In fig. 13, configuration 1b (row 1304) is similar to configuration 1a (row 1306), but is also included in CO ₂water gas shift reaction section before segregation section.Therefore, configuration 1b represents legacy system, Manzolini reference As mentioned above, and just Manzolini reference does not describe the recirculation of water gas shift reaction section or exhaust.For 1b configuration, realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 197km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 147lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 107.6km ²* year/megaton-CO ₂.The total power produced is ~ 609MW.Electrical efficiency is ~ 52.1%.

Configuration 3a, 3b and 3d correspond to its Anodic and export the configuration being used as the input of turbine combustion district.In such arrangements, the H of anode output ₂content is effective for the fuel be used as in turbine combustion district.This shows is favourable, because for generation of H ₂carbonaceous fuel produce in anode recirculation loop, wherein most of gained CO ₂can remove via low temperature separation process section.This also can cause the carbonaceous fuel amount being delivered to fuel section to reduce, but the CO during the minimizing of carbonaceous fuel also can cause negative electrode to input in combustion zone ₂concentration reduces.

Configuration 3a is the configuration being similar to configuration 1a, but has the recirculation of anode exhaust to combustion zone.Simulate four kinds of changes to 3a configuration.The 3a analog result be presented in row 1310 and 1312 is the configuration based on comprising EGR, and the analog result be presented in row 1314 and 1316 is the configuration based on not comprising EGR.Analog result shown in row 1310 and 1314 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1312 and 1316 is based on the simulation of operating voltage wherein keeping about 0.65.

Row 1310 show the analog result produced by the configuration being similar to most the 1a base case shown in row 1306.Realize the CO in the cathode exhaust gas of ~ 1.45% ₂fuel cell area needed for concentration is ~ 179km ².As the CO that a part for cathode exhaust gas is lost ₂amount is ~ 150.4lbsCO ₂/ MWhr.Catch CO per ton ₂fuel cell area be ~ 116.3km ²* year/megaton-CO ₂.The total power produced is ~ 599MW.Electrical efficiency is ~ 55.5%.Relative to configuration 1a, configuration 3a has lower trapping CO ₂total amount (configuration 1a ~ 1.88 million tons/year of vs. configuration 3a ~ 1.54 million tons/year).This is presumably because that the amount of the carbonaceous fuel being delivered to combustion zone reduces.But this also shows the CO being delivered to negative electrode input causing reducing ₂concentration, this CO causing models show to reduce for configuration 3a ₂removal efficiency.Configuration 3a shows has several advantage relative to configuration 1a.First, configuration 3a requires lower fuel cell area, and therefore the system configured in 3a can have the cost of reduction.In addition, the system table in configuration 3a reveals the electrical efficiency with improvement, and this can show that less fuel uses, even after adjusting the different capacity output of configuration.

Configuration 3b is similar to configuration 3a, but is also included in the water gas shift reaction district before low temperature separation process section.Simulate four kinds of changes to 3b configuration.The 3b analog result be presented in row 1318 and 1320 is the configuration based on comprising EGR, and the analog result be presented in row 1322 and 1324 is the configuration based on not comprising EGR.Analog result shown in row 1318 and 1322 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1320 and 1324 is based on the simulation of operating voltage wherein keeping about 0.65.

Simulation as shown in Figure 11, configuration 3b shows the CO via cathode exhaust gas with increase ₂discharge.This is presumably because the added hydrogen being delivered to combustion zone, this can cause the CO of the burning and gas-exhausting for negative electrode input ₂the corresponding reduction of amount.But fuel cell area reduces further.

Configuration 3d is similar to configuration 3b, but anode fuel utilization ratio by ~ 75% being reduced to ~ 50%.Simulate four kinds of changes to 3d configuration.The 3d analog result be presented in row 1326 and 1328 is the configuration based on comprising EGR, and the analog result be presented in row 1330 and 1332 is the configuration based on not comprising EGR.Analog result shown in row 1326 and 1330 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1328 and 1332 is based on the simulation of operating voltage wherein keeping about 0.65.

Configuration 3d is similar to configuration 3b, but anode fuel utilization ratio by ~ 75% being reduced to ~ 30%.

Row 1336 describe the result of the simulation carried out with the configuration similar with the configuration shown in Fig. 9.In fig .9, EGR998 first through negative electrode, then through HRSG854.Carry out simulating the base case 1a ' of this configuration.The analog result display row 1209 in fig. 13 of base case 1a '.Be different from base case, the analog result of row 1336 is based on ~ 50% but not the fuel availability of ~ 75%.In addition, the analog result of row 1336 is based on such configuration: wherein with the similar layout of configuration 3b and 3d in carry out reforming before entering anode with the methane by inputting anode ~ 20% change into H ₂.

Figure 14 display is from the result of the simulation carried out based on several configuration variant and alternative operational conditions.The factor more than the simulation explained with reference to Figure 11 is considered in the simulation of Figure 14 above.Configuration 4d with 4e represents such configuration: wherein will be separated (removing) CO ₂and H ₂after O remaining anode exhaust the recirculation inputted to anode and to the combustion zone of turbine recirculation between even partition.In order to anode input and combustion zone all provide enough hydrogen, the anode fuel utilization ratio in configuration 4d and 4e is set to ~ 50%.Configure the water gas shift reaction district before 4d and 4e is included in segregation section.Configuration 4d comprises independent reforming sections, with before entering anode at fuel by the described additional fuel input of anode ~ 20% to reform.Configuration 4e enters the reforming sections before anode input not included in fuel.

Simulate four kinds of changes to 4d configuration.The 4b analog result be presented in row 1410 and 1412 is the configuration based on comprising EGR, and the analog result be presented in row 1414 and 1416 is the configuration based on not comprising EGR.Analog result shown in row 1410 and 1414 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1412 and 1416 is based on the simulation of operating voltage wherein keeping about 0.65.

Simulate five kinds of changes to 4e configuration.The 4b analog result be presented in row 1420 and 1422 is the configuration based on comprising about 35%EGR, and the analog result be presented in row 1424 and 1426 is the configuration based on not comprising EGR.The 4e simulation of row 1428 is the configurations comprising about 45%EGR.Analog result shown in row 1420,1424 and 1428 is the simulation based on the operating voltage wherein keeping about 0.70.Analog result shown in row 1422 and 1426 is based on the simulation of operating voltage wherein keeping about 0.65.

Configuration 4f be similar to configuration 4e, unlike configuration 4f in anode fuel utilization ratio be ~ 33%, and configure in 4e be ~ 50% utilization ratio.Simulate four kinds of changes to 4e configuration.The 4f analog result be presented in row 1430 and 1432 is the configuration based on comprising about 35%EGR, and the analog result be presented in row 1434 and 1436 is the configuration based on not comprising EGR.Analog result shown in row 1430 and 1434 is based on the simulation of operating voltage wherein keeping about 0.70.Analog result shown in row 1432 and 1436 is based on the simulation of operating voltage wherein keeping about 0.65.

Row 1438 describe the result of the simulation carried out with the configuration similar with the configuration shown in Fig. 9.In fig .9, EGR998 first through negative electrode, then through HRSG854.Carry out simulating the base case 1a ' of this configuration.The analog result display row 1209 in fig. 13 of base case 1a '.Be different from base case, the analog result of row 1438 is based on ~ 50% but not the fuel availability of ~ 75%.In addition, the analog result of row 1438 is based on such configuration: wherein with the similar layout of configuration 4b and 4d in still carry out reforming before entering anode with the methane by inputting anode ~ 20% change into H ₂.

Although describe the present invention with regard to specific embodiments, the present invention is not limited thereto.Change/the amendment being applicable to operation in specific circumstances it will be apparent to those skilled in the art that.Therefore following patent requires to be intended to be interpreted as containing all change/amendments like this dropped in true spirit/scope of the present invention.

Claims

1., from a method for Combustion Source capturing carbon dioxide, the method comprises:

By combustion fuel stream with containing O ₂combustion zone introduced by stream;

Carry out combustion reactions in combustion zone and produce burning and gas-exhausting, burning and gas-exhausting comprises CO ₂;

Use the fuel cell array processing cathode inlet stream of one or more molten carbonate fuel cell, this cathode inlet stream comprises at least first part of burning and gas-exhausting, cathode exhaust gas stream is formed by least one cathode outlet of fuel cell array, described one or more molten carbonate fuel cell comprises one or more anode of fuel cell and one or more fuel battery negative pole, and described one or more molten carbonate fuel cell and combustion zone are operated by least one cathode inlet and be connected;

Make the carbonate from described one or more fuel battery negative pole and H ₂in described one or more anode of fuel cell, reaction produces the anode exhaust stream of electricity and at least one anode export from fuel cell array, and this anode exhaust stream comprises CO ₂and H ₂;

By anode exhaust stream separation of C O in one or more segregation section ₂, form poor CO ₂anode exhaust stream; And

By described poor CO ₂at least burns recirculated part of anode exhaust stream be sent to combustion zone.

2. the method for claim 1, it comprises further by described poor CO ₂the anode recirculation part of anode exhaust stream be recycled to described one or more anode of fuel cell.

3. the method for claim 2, it comprises further carbonaceous fuel is passed into described one or more anode of fuel cell, and this carbonaceous fuel optionally comprises CH ₄.

4. the method for claim 3, wherein passes into described one or more anode of fuel cell and comprises by carbonaceous fuel:

The reformation at least partially of carbonaceous fuel is produced H ₂; And

By the H produced ₂pass into described one or more anode of fuel cell at least partially.

5. the method for claim 3, wherein passes into described one or more anode of fuel cell by described carbonaceous fuel, before entering described one or more anode of fuel cell, described carbonaceous fuel is not sent into reforming sections.

6. the method any one of the claims, wherein said burning and gas-exhausting comprises the CO of about 10 volume % or lower ₂(the such as CO of 8 volume % ₂), described burning and gas-exhausting optionally comprises the CO of at least about 4 volume % ₂.

7. the method any one of the claims, it comprises further the second section of described burning and gas-exhausting is recycled to combustion zone, and this second section of described burning and gas-exhausting optionally comprises at least about 6 volume %CO ₂.

8. the method for claim 7, is wherein recycled to combustion zone by the second section of described burning and gas-exhausting and comprises:

At the second section of described burning and gas-exhausting and containing H ₂between O stream, exchanging heat forms steam;

By this second section Separation of Water of described burning and gas-exhausting, form poor H ₂the burning and gas-exhausting stream of O; And

By described poor H ₂the burning and gas-exhausting stream of O pass into combustion zone at least partially.

9. the method any one of the claims, wherein in one or more segregation section by described anode exhaust stream separation of C O ₂before, described anode exhaust stream comprises the hydrogen (such as at least about 10 volume % or at least about 15 volume %) of at least about 5.0 volume %.

10. the method any one of the claims, it is included in one or more segregation section further by described anode exhaust stream separation of C O ₂before, described anode exhaust stream is exposed to water gas converting catalyst, forms the anode exhaust stream through conversion, through the H of the anode exhaust stream of conversion ₂content is greater than the H of the anode exhaust stream before being exposed to water gas converting catalyst ₂content.

Method any one of 11. the claims, the fuel availability of wherein said one or more anode of fuel cell is about 45% to about 65% (as about 60% or lower).

Method any one of 12. the claims, wherein by described poor CO ₂the described burns recirculated part of anode exhaust stream pass into combustion zone before, by described poor CO ₂the described burns recirculated part of anode exhaust stream and combustion fuel stream merge.

Method any one of 13. the claims, wherein cathode exhaust gas stream has the CO of about 2.0 volume % or lower (such as about 1.5 volume % or lower or about 1.2 volume % or lower) ₂content.

Method any one of 14. the claims, wherein in one or more segregation section by described anode exhaust stream separation of C O ₂comprise the described anode exhaust stream of cooling, form the CO of condensation ₂phase.

The method of 15. claims 14, wherein in one or more segregation section by described anode exhaust stream separation of C O ₂be included in the CO forming condensation further ₂mutually from anode exhaust stream Separation of Water.

16. systems for generating electricity, comprising:

Comprise the combustion turbine of compressor, described compressor receives oxygenant input and is communicated with combustion zone fluid, and described combustion zone receives the input of at least one combustion fuel further, and described combustion zone is vented the decompressor fluid exported and is communicated with having;

Exhaust gas recycling system, which provides the first part exported at described expander exhaust gas and is communicated with the fluid between combustion zone;

Molten carbonate fuel cell array, it comprises one or more anode of fuel cell and one or more fuel battery negative pole, this molten carbonate fuel cell array has the input of at least one negative electrode, at least one negative electrode exports, at least one anode inputs and at least one anode exports, and the second section that described expander exhaust gas exports is communicated with at least one negative electrode input fluid described;

Anode recirculation loop, it comprises one or more carbon dioxide separation section and exports to form anode recirculation loop for separating of anode exhaust stream, the first part that anode recirculation loop exports is supplied to combustion zone and inputs as combustion fuel.

The system of 17. claims 16, is wherein supplied to described at least one anode input by the second section that described anode recirculation loop exports.

The system of 18. claims 16 or 17, wherein said anode recirculation loop also comprises water gas shift reaction section, described anode exhaust stream before at least one section of described one or more carbon dioxide separation section by described water gas shift reaction section.

System any one of 19. claim 16-18, wherein said exhaust gas recycling system also comprises heat recovery steam generation systems.

System any one of 20. claim 16-19, wherein said exhaust gas recycling system passes into compressor by the described first part exported by described expander exhaust gas and provides the first part exported at described expander exhaust gas and be communicated with the fluid between combustion zone.