CN111446466A - Multi-stage solid oxide fuel cell system, power generation system and power generation method - Google Patents
Multi-stage solid oxide fuel cell system, power generation system and power generation method Download PDFInfo
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- CN111446466A CN111446466A CN201910042735.3A CN201910042735A CN111446466A CN 111446466 A CN111446466 A CN 111446466A CN 201910042735 A CN201910042735 A CN 201910042735A CN 111446466 A CN111446466 A CN 111446466A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
- H01M8/04067—Heat exchange or temperature measuring elements, thermal insulation, e.g. heat pipes, heat pumps, fins
- H01M8/04074—Heat exchange unit structures specially adapted for fuel cell
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
- H01M8/04029—Heat exchange using liquids
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
- H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
- H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
- H01M8/0618—Reforming processes, e.g. autothermal, partial oxidation or steam reforming
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
- H01M8/2455—Grouping of fuel cells, e.g. stacking of fuel cells with liquid, solid or electrolyte-charged reactants
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
The application discloses multistage solid oxide fuel cell system, wherein, at least one the solid oxide fuel cell monomer the upper reaches of anode feed inlet are provided with at least one cooling unit, cooling unit is used for reducing and passes through the anode feed inlet gaseous temperature of fuel, and/or be used for reducing the free inside temperature of solid oxide fuel cell. The present application also relates to a power generation system and a power generation method using the above multistage solid oxide fuel cell system.
Description
Technical Field
The present application relates to the field of solid state batteries; in particular, the present application relates to a multi-stage solid oxide fuel cell system, and a power generation system including the same, and a method of generating power using the same.
Background
Solid oxide fuel cells are commonly used in power plants.
Disclosure of Invention
One aspect of the present application provides a multi-stage solid oxide fuel cell system comprising a plurality of solid oxide fuel cell cells;
each of the solid oxide fuel cells contains: the fuel gas is used as an anode, the oxygen-containing gas is used as a cathode, the anode and the cathode generate reacted gas after electrochemical reaction, an anode feed inlet connected with the anode, a cathode feed inlet connected with the cathode, and a process gas outlet for discharging process gas; the process gas comprises the unreacted fuel gas, the unreacted oxygen-containing gas, and the reacted gas;
the process gas outlet of the upstream solid oxide fuel cell is connected with the anode feed inlet of the downstream solid oxide fuel cell;
wherein, at least one solid oxide fuel cell monomer the upstream of anode feed inlet is provided with at least one cooling unit, cooling unit is used for reducing through the anode feed inlet the gaseous temperature of fuel, and/or be used for reducing the free inside temperature of solid oxide fuel cell.
In an embodiment of the present application, the process gas outlet of each solid oxide fuel cell at the upstream is connected to the anode feed inlet of the adjacent solid oxide fuel cell at the downstream;
the temperature reduction unit is arranged between the process gas outlet of each solid oxide fuel cell unit at the upstream and the anode feed inlet of the adjacent solid oxide fuel cell unit at the downstream.
In an embodiment of the present application, the fuel gas is a synthesis gas produced from a solid fuel and/or a liquid fuel; preferably synthesis gas produced from solid fuel;
the solid fuel is preferably coal, oil shale, and/or coke, more preferably coal; the liquid fuel is preferably petroleum, gasoline, and/or diesel.
In an embodiment of the present application, the cooling unit includes:
a heat exchanger for reducing the temperature of the fuel gas by a coolant; and/or
A methanator and/or a methane supply means for increasing the methane content of the fuel gas to promote the generation of an endothermic reforming reaction in the solid oxide fuel cell cells and increasing the proportion of the fuel gas in the process gas and thereby increasing the nernst potential;
preferably the methanator and/or methane supply means are such that the methane content in the fuel gas is at most 20 mole-%, more preferably at most 10 mole-%.
In an embodiment of the present application, the coolant is at least one selected from the group consisting of:
the balance gas separated by an air separation unit for separating air into oxygen and balance gas, the air separation unit for supplying the separated oxygen to the solid fuel and/or liquid fuel during production of the synthesis gas from the solid fuel and/or liquid fuel; and
other coolants at ambient temperature, such as ambient gas or ambient liquid, which preferably include water;
the balance gas preferably comprises nitrogen separated by an air separation unit.
In an embodiment of the present application, the heat exchanger is further capable of separating the process gas into an incompletely converted gas and a completely converted gas, wherein the incompletely converted gas is a gas having combustibility, which includes, for example, hydrogen gas and carbon monoxide gas; the fully converted gas comprises water vapor and carbon dioxide gas;
discharging the separated completely converted gas to the outside of the multi-stage solid oxide fuel cell system, and introducing the separated incompletely converted gas to the solid oxide fuel cell unit at the downstream.
In an embodiment of the application, each of the individual solid oxide fuel cells is configured to open the process gas outlet to discharge the process gas when an internal temperature of the individual solid oxide fuel cell is equal to or higher than a set temperature, and preferably, the process gas is discharged to the temperature reduction unit of the individual solid oxide fuel cell at the downstream;
the set temperature is 850-1000 ℃, preferably 850-950 ℃, and more preferably 850-900 ℃; most preferably 850 deg.c.
In the embodiment of the present application, in the case where the unit cells are connected in series in the multistage solid oxide fuel cell system, the number of the unit cells is at most 20, preferably at most 10, and more preferably less than 10;
after the heat exchange between the coolant and the process gas, the temperature of the coolant rises to 800 ℃ of 600-; and/or
The temperature of the process gas after heat exchange with the coolant is reduced to 800 ℃ of 600-;
preferably the temperature of the process gas after heat exchange is higher than the temperature of the coolant.
Another aspect of the present application relates to a power generation system comprising the aforementioned multi-stage solid oxide fuel cell system.
Yet another aspect of the present application relates to a method of generating electricity using the aforementioned multi-stage solid oxide fuel cell system.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a diagram of a prior art Integrated Gasification fuel cell system (IGFC);
fig. 2 is an arrangement of a multi-stage solid oxide fuel cell system according to an embodiment of the present application;
FIG. 3 is another arrangement of a multi-stage solid oxide fuel cell system according to an embodiment of the present application;
fig. 4 is a further arrangement of a multi-stage solid oxide fuel cell system according to an embodiment of the present application;
FIGS. 5(a) and 5(b) are graphs showing the relationship between temperature and cell efficiency according to an embodiment of the present application;
fig. 6 is a graph showing the required utilization of different numbers of individual solid oxide fuel cells having the same utilization to achieve 80% fuel utilization according to an embodiment of the present application;
fig. 7 is a diagram showing a relationship between the number of cells and the utilization rate of each cell in the case where the cell is realized by cells having different fuel utilization rates in order to obtain a fuel utilization rate of 80% according to an embodiment of the present application; and
figure 8 is a graph showing the effect of reduced degradation rate of fuel cells on the first year cost of electricity at different cost of a solid oxide fuel cell stack, according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Patent US 6,033,794 discloses the use of a multi-stage fuel cell. The patent discloses Molten Carbonate Fuel Cells (MCFCs) as the primary application. This patent uses different stages of cells where higher temperatures are accommodated by changing the materials of the fuel cell elements themselves.
Patent US 5,518,828 discloses a molten carbonate fuel cell that can be used in multiple stages (multiple solid oxide fuel cell cells) including inter-cooling units between fuel cells. Moreover, this patent discloses co-current and counter-current arrangements of fuel gas (i.e., gas as anode) and oxidant gas (i.e., gas as cathode) flows.
Patent US 5,413,878 also discloses a multi-stage molten carbonate fuel cell. The drawings of this patent show that heat is removed from between the two stages of fuel gas and oxidant gas. However, the patent does not specify why and how intercooling between the fuel cell cells is performed.
It can be seen that the multi-stage cells disclosed in the prior art patents are all molten carbonate fuel cells, and further, the material of the intercooling unit employed therein, or the material of the fuel cell elements themselves, needs to be changed.
The present application relates to a multi-stage Solid Oxide Fuel Cell System (SOFC) comprising a plurality of Solid Oxide Fuel Cell cells;
each of the solid oxide fuel cells contains: the fuel gas is used as an anode, the oxygen-containing gas is used as a cathode, the anode and the cathode generate reacted gas after electrochemical reaction, an anode feed inlet connected with the anode, a cathode feed inlet connected with the cathode, and a process gas outlet for discharging process gas; the process gas comprises the unreacted fuel gas, the unreacted oxygen-containing gas, and the reacted gas;
the process gas outlet of the upstream solid oxide fuel cell is connected with the anode feed inlet of the downstream solid oxide fuel cell;
wherein, at least one solid oxide fuel cell monomer the upstream of anode feed inlet is provided with at least one cooling unit, cooling unit is used for reducing through the anode feed inlet the gaseous temperature of fuel, and/or be used for reducing the free inside temperature of solid oxide fuel cell.
Temperature control is very important for long term reliability and performance of solid oxide fuel cells. A recent study found that using the same material to raise the electrical stack (stack) temperature from 700 c to 800 c increased the degradation coefficient by 24. The electrochemical reaction occurring in the fuel cell is exothermic, and thus the temperature rises as the reaction proceeds. Further, when the reaction occurs, the fuel is consumed, and therefore the rise in temperature starts to tend to be smooth. This results in temperature non-uniformity in the battery. Hot zones result in reduced lifetime and reduced performance reliability. On the other hand, higher operating temperatures are required because higher operating temperatures increase the efficiency of the fuel cell due to increased reaction rates, higher mass transfer rates, and lower cell resistance (due to higher ionic conductivity of the electrolyte). Where the specific temperature of a molten carbonate fuel cell needs to be above 600 ℃, because it allows internal reforming (which is an endothermic reaction), the reaction is inherently endothermic and helps control the internal temperature. High temperature operation has disadvantages associated with the choice of materials for fabrication. The problems arising from differences in thermal expansion coefficients and local reactions cause high mechanical stresses, reduce the service life of the fuel cell, cause degradation and affect performance over time.
At least one cooling unit is arranged on the upstream of the anode feed inlet of the solid oxide fuel cell unit in the multi-stage solid oxide fuel cell system, and the cooling unit is used for reducing the temperature of the fuel gas and/or the internal temperature of the solid oxide fuel cell unit. The application adopts a plurality of smaller solid oxide fuel cell units, wherein in each solid oxide fuel cell unit, the utilization rate of fuel is smaller than that of a single large stack. However, the multi-stage solid oxide fuel cell system of the present application will improve the reliability, performance and lifetime of the solid oxide fuel cell system.
Furthermore, regarding the most upstream solid oxide fuel cell, since it uses the fuel gas as the anode instead of using the gas containing the process gas as the anode, it is not necessary to connect the anode feed opening of the most upstream solid oxide fuel cell with the temperature decreasing unit.
In an embodiment of the present application, the process gas outlet of each solid oxide fuel cell at the upstream is connected to the anode feed inlet of the adjacent solid oxide fuel cell at the downstream; the temperature reduction unit is arranged between the process gas outlet of each solid oxide fuel cell unit at the upstream and the anode feed inlet of the adjacent solid oxide fuel cell unit at the downstream.
Namely, a temperature reduction unit is arranged between each upstream solid oxide fuel cell and the immediately downstream solid oxide fuel cell. The multistage solid oxide fuel cell system arranged in this way is more efficient because the process gas in only the most downstream solid oxide fuel cell unit is not subjected to the cooling effect of the cooling unit.
In embodiments of the present application, the fuel gas is a synthesis gas (syngas) generated from a solid fuel and/or a liquid fuel; preferably synthesis gas produced from solid fuel; the solid fuel is preferably coal, oil shale, and/or coke, more preferably coal; the liquid fuel is preferably petroleum, gasoline, and/or diesel.
Among them, the fuel gas is more preferably a synthetic gas obtained by gasifying a solid fuel and an oxygen-containing gas, for example, a synthetic gas produced by burning a solid fuel with air and/or oxygen or the like. The fuel gas can be supplied to the battery cell including H2And/or CO for oxidation.
In an embodiment of the present application, the cooling unit includes: heat exchanger for passing coldA coolant to lower the temperature of the fuel gas; and/or a methanator and/or a methane supply means for increasing the methane content of the fuel gas to promote the production of endothermic reforming reactions in the solid oxide fuel cell cells and to increase the proportion of the fuel gas in the process gas and thereby increase the nernst potential; preferably the methanator and/or methane supply means are such that the methane content in the fuel gas is at most 20 mole-%, more preferably at most 10 mole-%. Methane to provide H2And CO thereby enables an increase in the nernst potential (in other words, an increase in the proportion of fuel that can undergo electrochemical reactions in the gas).
In general, solid oxide fuel cells can use a variety of fuels. Most commonly methane and/or natural gas or higher hydrocarbons are used. The methane content of natural gas is high. The high methane content can facilitate internal reforming reactions that occur within the solid oxide fuel cell. The reforming reaction has two main purposes: a) providing H2And CO; b) the temperature rise of the electrochemical reaction is controlled by the endothermic reaction taking place inside the fuel cell. Temperature control is difficult to achieve since electrochemical reactions tend to increase temperature, which increases the rate of degradation. Two methods of controlling the temperature rise are: a) cooling the interior of the solid oxide fuel cell with an oxygen-containing gas as an oxidant; b) internal reforming is performed using natural gas or synthesis gas with higher methane content in the fuel cell. The first method is limited by the amount of oxidant required for the electrochemical reaction. A large excess of air is used to keep cool to maintain the temperature inside the fuel cell. For a 550MWe (550 megawatt power) system, the additional airflow requires about 23MWe of auxiliary power. In this case, only 20% of the oxygen in the air is used for the electrochemical reaction. The second method is limited by the reforming reaction that occurs in only one solid oxide fuel cell and therefore cannot reach a constant temperature. The present application employs a multi-stage approach to control the internal temperature and partial pressure of the fuel cell (e.g., by separating out the partially reformed fuel gas of undesired components (e.g., fully reformed gas) or selectively removing undesired components between individual SOFC cellsTo increase the partial pressure of the combustible gas in the anode feed port) and thus control the fuel conversion of the overall solid oxide fuel cell system.
If the air flow rate is reduced (oxidant utilization increased to 80% instead of 20%), the auxiliary power to the air compressor is reduced, thereby increasing the overall efficiency from 39.5% to 40.8% for case 1.1 in the DOE IGFC report (technical-Economic Analysis of Integrated gasification Fuel Cell Systems Created by Energy efficient turbine Planning and Analysis for SEAP & OPPB, SEAP and OPPB Energy Sector Planning and analyzing the technical Economic Analysis of the integrated gasification Fuel Cell Systems Created, November 24, 2014, DOE/NET L-341/112613, assuming the other parameters remain unchanged.
In the embodiment of the present application, in the case that the temperature reduction unit includes the heat exchanger, any fluid having a temperature below the temperature of the process gas generated by the solid oxide fuel cell unit may be used to exchange heat with the process gas. For example, any fluid at normal or slightly elevated temperature (e.g., temperature below 700 ℃, preferably below 600 ℃, and more preferably below 500 ℃) may be used, since the process gas generated by the solid oxide fuel cell typically has a very high temperature, e.g., 850-; most preferably 850 deg.c.
Specifically, the coolant is at least one selected from the group consisting of: the residual gas separated by an Air Separation Unit (ASU) for separating air into oxygen and residual gas, the air separation unit being used to supply the separated oxygen to the solid fuel and/or liquid fuel during the production of the synthesis gas from the solid fuel and/or liquid fuel; and other coolants at ambient temperature, such as ambient gas or ambient liquid, which preferably include water; the balance gas preferably comprises nitrogen separated by an air separation unit.
That is, the air separation unit is used to supply the separated oxygen to the solid fuel and/or liquid fuel during the production of the synthesis gas from the solid fuel and/or liquid fuel, and during the production of oxygen, a surplus gas other than oxygen is also produced, which typically contains nitrogen, for example. The balance gas and/or other coolant at normal temperature may be used to exchange heat with the process gas generated from the sofc cell.
In an embodiment of the present application, the heat exchanger is further capable of separating the process gas into an incompletely converted gas and a completely converted gas, wherein the incompletely converted gas is a gas having combustibility, which includes, for example, hydrogen gas and carbon monoxide gas; the fully converted gas comprises water vapor and carbon dioxide gas; discharging the separated completely converted gas to the outside of the multi-stage solid oxide fuel cell system, and introducing the separated incompletely converted gas to the solid oxide fuel cell unit at the downstream.
Among them, the incompletely converted gas is a gas having combustibility, and includes, for example, hydrogen gas and carbon monoxide gas. For example, the boiling point of the incompletely converted gas may be lower relative to the completely converted gas (e.g., which comprises water and carbon dioxide gas). Therefore, incompletely converted gas and completely converted gas can be separated, so that the incompletely converted gas can be used for subsequent solid oxide fuel cell monomer reaction, and the efficiency of the solid oxide fuel cell is improved. For example, the separated incompletely converted gas may be connected to the anode feed port of the downstream solid oxide fuel cell.
In an embodiment of the present application, each of the individual solid oxide fuel cells is configured to open the process gas outlet to discharge the process gas when an internal temperature of the individual solid oxide fuel cell is equal to or higher than a set temperature, and preferably to discharge the process gas to the temperature reduction unit of the individual solid oxide fuel cell downstream; the set temperature is 850-1000 ℃, preferably 850-950 ℃, and more preferably 850-900 ℃; most preferably 850 deg.c.
When the internal temperature of the solid oxide fuel cell is equal to or higher than the set temperature, the generated process gas (which is usually a high-temperature gas) is discharged to the outside of the solid oxide fuel cell.
Preferably, the process gas is discharged to the temperature reduction unit of the solid oxide fuel cell unit downstream. The process gas discharged to the temperature reduction unit of the downstream solid oxide fuel cell can be further utilized by the downstream solid oxide fuel cell.
In the embodiment of the present application, in the case where the unit cells are connected in series in the multistage solid oxide fuel cell system, the number of the unit cells is at most 20, preferably at most 10, and more preferably less than 10.
In the case that the battery cells are in a series connection relationship, one or more battery cells in a parallel connection relationship with the battery cells may be optionally provided for each of the battery cells in the series connection relationship. In the case of the connection relationship described in this paragraph, the number of battery cells exhibiting a series connection relationship is at most 20, preferably at most 10, and more preferably less than 10. .
In the case of the connection relationship described in the above paragraph, the pressure of each battery cell may be a conventional pressure used in the art. Optionally, a compression device or a decompression device may be used to adjust the pressure between the cells. Among them, each of the battery cells exhibiting the series connection relationship preferably exhibits the same pressure, for example, 1atm, 10atm, 20atm or the like.
Any fluid having a temperature below the temperature of the process gas generated by the individual solid oxide fuel cells serves as a coolant, and after the coolant exchanges heat with the process gas of the present application, the temperature of the coolant will rise and the temperature of the process gas will fall.
Wherein the temperature of the coolant after heat exchange with the process gas is increased to 600-800 ℃, preferably to 650-750 ℃, further preferably to 700-750 ℃, and further preferably to 700 ℃; and/or the temperature of the process gas after the heat exchange with the coolant is reduced to 600-800 ℃, preferably to 650-750 ℃, further preferably to 700-750 ℃, and further preferably to 700 ℃; preferably the temperature of the process gas after heat exchange is higher than the temperature of the coolant.
Furthermore, in the case where gas is generated after the coolant temperature rises, it can also be used to generate additional electricity. Preferably, the warmed gaseous coolant may be used with steam from a Heat Recovery Steam Generator (HRSG) to generate electricity.
The present application also relates to a power generation system comprising the aforementioned multi-stage solid oxide fuel cell system.
The present application further relates to a method of generating electricity using the aforementioned multi-stage solid oxide fuel cell system.
The multistage solid oxide fuel cell system, the power generation system and the power generation method of the application use the temperature reduction unit, and further use the coolant in the temperature reduction unit to exchange heat with the generated process gas. The coolant adopted by the application can produce the following effects: a) performing temperature control of the solid oxide fuel cell cells, b) controlling the partial pressure and composition of the combustible gas in the anode feed port by separating out undesired components of the partially reformed fuel gas (e.g., fully reformed gas) or selectively removing undesired components between individual solid oxide fuel cell cells, c) reducing the flow of air (which is typically used as the cathode) required to maintain internal cooling of the solid oxide fuel cell cells, and d) reducing degradation due to better temperature control of the solid oxide fuel cell cells.
The present application differs from the concepts disclosed in patents US 5,518,828 and US 5,413,878 in a number of ways: a) the present application relates to the use of a multi-stage solid oxide fuel cell system with a temperature reduction unit in an integrated gasification fuel cell system; b) the type of fuel cell used is a solid oxide fuel cell, rather than the molten carbonate fuel cell disclosed in the prior art patents; c) cooling is performed by utilizing the balance gas (which typically contains nitrogen) produced by the air separation unit in the integrated gasification fuel cell system. While the intercooling disclosed in other patents does not have the coolant available in the overall system described in this application; d) staging as disclosed in this application may also include varying the total pressure of the feed stream between stages (total pressure here refers to both gas pressure as anode and cathode in the cell, since the pressure differential across the anode and cathode needs to be minimized to maintain cell integrity) by increasing the total pressure to obtain additional fuel conversion; e) the staging disclosed herein may also utilize other methods of removing undesired components from partially converted fuel gas by cryogenic separation or selectively removing undesired components between stages to increase the partial pressure of the fuel gas stream e) using the synthesis gas obtained by gasification of the fuel as fuel.
Example 1 reference example of the prior art
Fig. 1 is a layout diagram of an example of an integrated gasification fuel cell system in the prior art. Wherein coal is gasified as fuel in a gasifier (gasifier) together with oxygen (in which case oxygen separated by an air separation unit ASU may be used); the syngas produced after the gasification of the fuel with oxygen then enters a syngas cleaner, thereby removing impurities in the syngas, such as particulates, sulfur, and other contaminants such as mercury, and producing a clean syngas; the synthesis gas then enters a synthesis gas expander (expander) to expand the synthesis gas from a high pressure to the operating pressure of the fuel cell cells; the synthesis gas passing through the expander is fed as an anode to the solid oxide fuel cell.
Air or an oxygen-containing gas (e.g., oxygen) is also fed into the solid oxide fuel cell as a cathode, and the air or oxygen may be fed into the compressor before being fed into the solid oxide fuel cell.
The anode exhaust gas is combusted in an oxygen-combustor to produce CO2And H2Hot mixture of O, the mixture being expanded and cooled to condense out water and capture CO2。
It is noted that the heat recovered from the process of treating the synthesis gas, the oxygen burner off-gas and the cathode off-gas, as well as any process heat generated during the synthesis gas cleaning, may be sent to the heat recovery steam generator HRSG.
Example 2
FIG. 2 is a flow chart of a cooling process using nitrogen in the examples of the present application.
Wherein the synthesis gas generated in fig. 2 is fed to the cells of the first stage, partially converted into electric energy, except for the common part of fig. 1. In this process, the temperature rises, and thus the partially reformed fuel gas (sometimes referred to simply as fuel gas) is cooled by the low temperature nitrogen produced by the air separation unit. The cooled fuel gas is then fed to the cells of the second stage where the process is repeated until the desired fuel conversion is achieved. Alternatively, water may be used to reduce the temperature of the combustion gases and in the process generate steam, which may be used to generate additional electricity along with steam generated by a Heat Recovery Steam Generator (HRSG).
Example 3
FIG. 3 is a flow chart of a process for cryogenic separation and temperature control using nitrogen in the examples of the present application.
Wherein fig. 3 relates to the use of low-temperature nitrogen gas by condensing H formed due to electrochemical reactions occurring in the previous-stage battery cell, except for the common part of fig. 12O and CO2To cryogenically separate the partially reformed fuel into its components, specifically into an incompletely reformed gas (which includes hydrogen gas and carbon monoxide gas) and a completely reformed gas (which includes water vapor and carbon dioxide gas).
Then the H is added after the temperature of the gas stream is raised to about 700-2And CO is fed to the second stage cell. The heat of the reforming fuel of about 850 ℃ -. Due to better temperature control and by higher H in the fuel inlet2And CO partial pressure, the efficiency of the solid oxide fuel cell is improved.
Example 4
Fig. 4 is a process flow diagram in an example of the present application that utilizes a high methane content synthesis gas inlet between the methanator and the solid oxide fuel cell to better control the internal temperature within the solid oxide fuel cell.
Wherein figure 4 relates to controlling the temperature inside the fuel cell by a higher methane content in the anode feed inlet, except as in the common part of figure 1. This is achieved by reacting H2And a methanator for converting the CO to a high methane content synthesis gas. The methane content of the synthesis gas controls the temperature inside the fuel cell by the endothermic reforming reaction that takes place in the solid oxide fuel cell cells.
As shown in fig. 2 to 4, the battery cells of each stage may be connected in series. One upstream cell may be connected to a plurality of downstream cells, or a plurality of upstream cells may be connected to one downstream cell, without affecting the performance of the multistage solid oxide fuel cell system of the present application.
Example 5
In general, higher temperatures result in higher cell efficiency at the same current density (as shown in fig. 5 (a)), and a temperature gradient exists within the fuel cell at the same flow rate (as shown in fig. 5 (b)). Higher temperatures are required for higher efficiency, but at the same time there is a temperature gradient in the fuel cell, resulting in temperature non-uniformity, which is undesirable.
Wherein dp, which is one of the ordinate in fig. 5(a), means power density (power density).
Furthermore, as previously mentioned, temperature control is important to the long term reliability and performance of solid oxide fuel cells. A recent study found that using the same material to raise the stack temperature from 700 c to 800 c increased the degradation coefficient by 24. It is therefore apparent that the fuel cell has better temperature uniformity and lower degradation (or longer life) when the fuel cell is in the state of including the intermediate cooling unit.
Example 6
Fig. 6 shows the equal fuel utilization required for each cell if the fuel cell is divided into a number of cells. As is clear from the following figures, a single solid oxide fuel cell will require a fuel utilization of 80% (example), while two solid oxide fuel cells with the same utilization will require a fuel utilization of about 55%.
Example 7
Fig. 7 shows that the grading can also be performed in a different way. In the figure, the required fuel utilization is still 80%, but is achieved by different fuel utilizations of the stages (the broken lines from left to right represent 1 to 10 stages, respectively). Specifically, in the case of using 3 cells (i.e., the broken line of the second from the left in the figure), the fuel utilization rate of the first cell is about 27%, the fuel utilization rate of the second cell is about 34%, the fuel utilization rate of the third cell is about 59%, and the total fuel utilization rate of the multi-stage battery composed of three cells is 80%.
Many different scenarios can be envisaged where the size, and/or processing power of each solid oxide fuel cell is set in order to achieve different fuel utilization rates while keeping the overall fuel utilization rate unchanged. This allows for better temperature control, overall performance and fuel cell life.
The battery components used in the embodiments of the present application may be those conventionally used in the art, and may be available from fuel Cell Energy, for example. In addition, other materials and/or components used in the embodiments of the present application may also be used as materials and/or components conventionally used in the art, as long as the technical effects of the present application are not affected.
Example 8
Figure 8 shows the effect of reduced fuel cell degradation rate (increased life of the fuel cell stack and thus increased age for replacing the fuel cell stack) on the First annual cost of electricity (FY COE) for DOE case 1.1 at different cost of the solid oxide fuel cell stack. In the figure, the data from top to bottom are data for the case of 3000 to 1000$/kWe, respectively. Among other things, the degradation rate affects the life of the fuel cell stack, which is related to the number of years of replacement. Degradation rates highlight the data at 1, 2, 3, 4 and 7 years, which correspond to degradation rates of 1.5%/1000 hours to 0.2%/1000 hours.
The use of multiple solid oxide fuel cell cells, including an intermediate cooling unit, can significantly reduce the degradation rate on a large scale. It can thus be seen that, for example, at a cost of $ 1000/kilowatt of electricity for a solid oxide fuel cell stack, the degradation rate decreases from 1.5%/1000 hours to 0.35%/1000 hours, increasing the lifetime from 1 year to 4 years, and decreasing the electricity cost by over 22% for the first year. The stages therebetween are cooled by low temperature nitrogen generated by an Air Separation Unit (ASU) in the integrated gasification fuel cell system.
The above analysis does not include the beneficial effect of changing the partial pressure of the combustible gas in the anode feed port, since when H is present2O and CO2By using cold N2When the fuel gas is separated from the fuel gas by low-temperature separation, the partial pressure of the fuel is high. This is expected to increase the beneficial effect.
Claims (10)
1. A multi-stage solid oxide fuel cell system comprising a plurality of solid oxide fuel cell cells;
each of the solid oxide fuel cells contains: the fuel gas is used as an anode, the oxygen-containing gas is used as a cathode, the anode and the cathode generate reacted gas after electrochemical reaction, an anode feed inlet connected with the anode, a cathode feed inlet connected with the cathode, and a process gas outlet for discharging process gas; the process gas comprises the unreacted fuel gas, the unreacted oxygen-containing gas, and the reacted gas;
the process gas outlet of the upstream solid oxide fuel cell is connected with the anode feed inlet of the downstream solid oxide fuel cell;
wherein, at least one solid oxide fuel cell monomer the upstream of anode feed inlet is provided with at least one cooling unit, cooling unit is used for reducing through the anode feed inlet the gaseous temperature of fuel, and/or be used for reducing the free inside temperature of solid oxide fuel cell.
2. The multi-stage solid oxide fuel cell system of claim 1, wherein the process gas outlet of each solid oxide fuel cell upstream is connected to the anode feed inlet of the adjacent solid oxide fuel cell downstream;
the temperature reduction unit is arranged between the process gas outlet of each solid oxide fuel cell unit at the upstream and the anode feed inlet of the adjacent solid oxide fuel cell unit at the downstream.
3. The multi-stage solid oxide fuel cell system of claim 1 or 2, wherein the fuel gas is a synthesis gas generated from a solid fuel and/or a liquid fuel; preferably synthesis gas produced from solid fuel;
the solid fuel is preferably coal, oil shale, and/or coke, more preferably coal; the liquid fuel is preferably petroleum, gasoline, and/or diesel.
4. The multi-stage solid oxide fuel cell system of any of claims 1 to 3, wherein the temperature reduction unit comprises:
a heat exchanger for reducing the temperature of the fuel gas by a coolant; and/or
A methanator and/or a methane supply means for increasing the methane content of the fuel gas, thereby promoting the generation of an endothermic reforming reaction in the solid oxide fuel cell cells and increasing the proportion of the fuel gas in the process gas and thereby increasing the nernst potential;
preferably the methanator and/or methane supply means are such that the methane content in the fuel gas is at most 20 mole-%, more preferably at most 10 mole-%.
5. The multi-stage solid oxide fuel cell system of claim 4, wherein the coolant is at least one selected from the group consisting of:
the balance gas separated by an air separation unit for separating air into oxygen and balance gas, the air separation unit for supplying the separated oxygen to the solid fuel and/or liquid fuel during production of the synthesis gas from the solid fuel and/or liquid fuel; and
other coolants at ambient temperature, such as ambient gas or ambient liquid, which preferably include water;
the balance gas preferably comprises nitrogen separated by an air separation unit.
6. The multi-stage solid oxide fuel cell system of claim 4 or 5, wherein the heat exchanger is further capable of separating the process gas into incompletely converted gas and completely converted gas, wherein the incompletely converted gas is a gas having combustibility, including, for example, hydrogen gas and carbon monoxide gas; the fully converted gas comprises water vapor and carbon dioxide gas;
discharging the separated completely converted gas to the outside of the multi-stage solid oxide fuel cell system, and introducing the separated incompletely converted gas to the solid oxide fuel cell unit at the downstream.
7. The multi-stage solid oxide fuel cell system of any one of claims 1 to 6, wherein each of the solid oxide fuel cells is configured to open the process gas outlet to discharge the process gas when an internal temperature of the solid oxide fuel cell is above a set temperature, and preferably to discharge the process gas to the temperature reduction unit of the downstream solid oxide fuel cell;
the set temperature is 850-1000 ℃, preferably 850-950 ℃, and more preferably 850-900 ℃; most preferably 850 deg.c.
8. The multi-stage solid oxide fuel cell system of any one of claims 4 to 7, wherein in the case where the unit cells are connected in series in the multi-stage solid oxide fuel cell system, the number of the unit cells is at most 20, preferably at most 10, more preferably less than 10;
after the heat exchange between the coolant and the process gas, the temperature of the coolant rises to 800 ℃ of 600-; and/or
The temperature of the process gas after heat exchange with the coolant is reduced to 800 ℃ of 600-;
preferably the temperature of the process gas after heat exchange is higher than the temperature of the coolant.
9. A power generation system comprising a multi-stage solid oxide fuel cell system as claimed in any preceding claim.
10. A method of generating electricity using the multi-stage solid oxide fuel cell system of any one of claims 1 to 8.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1370333A (en) * | 1999-08-16 | 2002-09-18 | 塞拉米克燃料电池有限公司 | Fuel cell system |
| CN1393952A (en) * | 2001-07-04 | 2003-01-29 | 上海神力科技有限公司 | Deionizing system for fuel battery |
| US20070184315A1 (en) * | 2006-02-09 | 2007-08-09 | Kelly Sean M | Control of fuel cell stack electrical operating conditions |
| CN102379057A (en) * | 2009-04-01 | 2012-03-14 | 松下电器产业株式会社 | Fuel cell system |
| JP2013114849A (en) * | 2011-11-28 | 2013-06-10 | Aisin Seiki Co Ltd | Fuel cell system |
| WO2014119221A1 (en) * | 2013-01-30 | 2014-08-07 | Honda Motor Co., Ltd. | Fuel cell module |
| CN105144450A (en) * | 2013-02-11 | 2015-12-09 | 麦卡利斯特技术有限责任公司 | Fuel-cell systems operable in multiple modes for variable processing of feedstock materials and associated devices, systems, and methods |
| CN106058287A (en) * | 2016-06-27 | 2016-10-26 | 南京特亿达新能源科技有限公司 | SOFC (Solid Oxide Fuel Cell) independent power generation system capable of producing hydrogen by reforming natural gas |
| CN107925105A (en) * | 2015-08-10 | 2018-04-17 | 日产自动车株式会社 | Solid oxide fuel cell system |
| CN108232231A (en) * | 2016-12-19 | 2018-06-29 | 国家能源投资集团有限责任公司 | Mine backup power system of fuel cell |
-
2019
- 2019-01-16 CN CN201910042735.3A patent/CN111446466B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1370333A (en) * | 1999-08-16 | 2002-09-18 | 塞拉米克燃料电池有限公司 | Fuel cell system |
| CN1393952A (en) * | 2001-07-04 | 2003-01-29 | 上海神力科技有限公司 | Deionizing system for fuel battery |
| US20070184315A1 (en) * | 2006-02-09 | 2007-08-09 | Kelly Sean M | Control of fuel cell stack electrical operating conditions |
| CN102379057A (en) * | 2009-04-01 | 2012-03-14 | 松下电器产业株式会社 | Fuel cell system |
| JP2013114849A (en) * | 2011-11-28 | 2013-06-10 | Aisin Seiki Co Ltd | Fuel cell system |
| WO2014119221A1 (en) * | 2013-01-30 | 2014-08-07 | Honda Motor Co., Ltd. | Fuel cell module |
| CN105144450A (en) * | 2013-02-11 | 2015-12-09 | 麦卡利斯特技术有限责任公司 | Fuel-cell systems operable in multiple modes for variable processing of feedstock materials and associated devices, systems, and methods |
| CN107925105A (en) * | 2015-08-10 | 2018-04-17 | 日产自动车株式会社 | Solid oxide fuel cell system |
| CN106058287A (en) * | 2016-06-27 | 2016-10-26 | 南京特亿达新能源科技有限公司 | SOFC (Solid Oxide Fuel Cell) independent power generation system capable of producing hydrogen by reforming natural gas |
| CN108232231A (en) * | 2016-12-19 | 2018-06-29 | 国家能源投资集团有限责任公司 | Mine backup power system of fuel cell |
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