US20110014578A1 - Coal-fired power station and method for operating the coal-fired power station - Google Patents

Coal-fired power station and method for operating the coal-fired power station Download PDF

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US20110014578A1
US20110014578A1 US12/864,336 US86433609A US2011014578A1 US 20110014578 A1 US20110014578 A1 US 20110014578A1 US 86433609 A US86433609 A US 86433609A US 2011014578 A1 US2011014578 A1 US 2011014578A1
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Prior art keywords
flue gas
steam generator
combustion
gas
steam
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US12/864,336
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English (en)
Inventor
Andreas Rohde
Christian Bergins
Friedrich Klauke
Martin Ehmann
Thorsten Buddenberg
Bernd Vollmer
Thomas Krause
Alfred Gwosdz
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Hitachi Power Europe GmbH
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Hitachi Power Europe GmbH
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Assigned to HITACHI POWER EUROPE GMBH reassignment HITACHI POWER EUROPE GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BUDDENBERG, THORSTEN, EHMANN, MARTIN, ROHDE, ANDREAS, KRAUSE, THOMAS, VOLLMER, BERND, BERGINS, CHRISTIAN, GWOSDZ, ALFRED, KLAUKE, FRIEDRICH
Publication of US20110014578A1 publication Critical patent/US20110014578A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/006—Layout of treatment plant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/003—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for pulverulent fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L7/00—Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam
    • F23L7/007—Supplying oxygen or oxygen-enriched air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
    • F23L2900/07007—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber using specific ranges of oxygen percentage
    • 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
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/32—Direct CO2 mitigation
    • 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
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

  • the invention relates to a method for operating and for controlling a power station which comprises a coal-fired steam generator, whose steam generator is designed for steam parameters which can be achieved for coal combustion, which is carried out with combustion air, in the steam generator by heat transfer to the steam mass flow.
  • the invention furthermore relates to a coal-fired power station having a coal-fired steam generator whose steam generator is designed for steam parameters which can be achieved for coal combustion, which is carried out with combustion air, in the steam generator by heat transfer to the steam mass flow.
  • the CO 2 which is present in a small concentration ( ⁇ 13% by volume) in the flue gas is absorbed with washing solutions in a packed column with energy being released, and is desorbed in a second column, with energy being supplied.
  • the additional energy supply which is required for desorption (generally in the form of energy supplied from steam tapped off from the medium-pressure turbine) leads to decreases in efficiency of 10-12 percentage points in comparison to power stations without such CO 2 capture.
  • This technology has the advantage, inter alia, that the method is carried out after the combustion process and has no reactions on the steam generator, thus allowing existing power stations to be retrofitted.
  • the disadvantages include the large amount of space required for the flue gas washer and the high energy consumption which—in the case of possible retrofitting—results in a large amount of modification effort in the area of the steam circuit and of the turbine.
  • the CO 2 concentration in the flue gas is greatly increased by using a mixture of fed-back flue gas and virtually pure oxygen instead of air for combustion of the coal.
  • the sealing of the power station installation which for safety reasons is still operated at a slightly reduced pressure—with all its components, the purity of the oxygen taken from an air separation unit (ASU), the quality of the flue gas cleaning installations (denitrification (DeNOx), desulfurization (DeSOx), dust removal) and the process control—particularly the location of the flue gas feed back (for example the points/locations 1 - 6 in FIG. 1 )—are the critical factors for the purity of the CO 2 which leaves the process after flue gas drying (condensation of the water by cooling).
  • the CO 2 concentration should in any case be sufficiently high, and the hazardous-substance load so low, that the CO 2 can be compressed directly and be supplied for storage.
  • the advantage of this concept is that both the steam generator as well as the steam circuit and the turbine design, which are designed for a conventional air mode, do not fundamentally differ from those which are designed for the oxyfuel mode.
  • the efficiency reductions in this process are 8-10 percentage points lower than in the case of downstream CO 2 flue gas washing, in comparison to power stations without CO 2 capture. These reductions are contributed to significantly by the electrical energy required for the air separation unit that has to be installed itself (>60% of the reductions) as well as the additional flue gas compression (>25% of the reductions).
  • the proportion of the other units required in comparison to conventional coal-fired power stations in the additional energy requirement is ⁇ 15%.
  • the invention is therefore based on the object of providing a solution which allows coal-fired power stations designed for air operation to be operated with combustion of the fuel based on the oxyfuel process in the furnace area of the steam generator of the coal-fired power station.
  • this object is achieved according to the invention in that combustion of the fuel, which contains carbon, is carried out in the steam generator on the basis of the oxyfuel process with approximately pure oxygen, which contains more than 95% by volume of O 2 , and recirculated flue gas with a high CO 2 content, such that the mass flows of all the fuel flows as well as combustion gas flows, feed gas flows and process gas flows which are supplied to the coal-burners and to the steam generator are formed from combustion oxygen and/or recirculated flue gas in their respective composition ratio of oxygen and/or flue gas, and are matched to one another, such that the heat transfer which takes place in the steam generator by flame radiation, gas radiation and convection to the steam mass flow in the steam/water circuit of the steam generator is kept the same overall in comparison to the air combustion, in particular with the same steam parameters being maintained.
  • the above-mentioned object is achieved according to the invention in an analogous manner in that combustion of the fuel, which contains carbon, is carried out in the steam generator on the basis of the oxyfuel process with approximately pure oxygen, which contains more than 95% by volume of O 2 , and recirculated flue gas with a high CO 2 content, such that the mass flows of all the fuel flows as well as combustion gas flows, feed gas flows and process gas flows which are supplied to the coal-burners and to the steam generator are formed from combustion oxygen and/or recirculated flue gas in their respective composition ratio of oxygen and/or flue gas, and are matched to one another, such that the heat transfer which takes place in the steam generator by flame radiation, gas radiation and convection to the steam mass flow in the steam/water circuit of the steam generator remains the same overall in comparison to the air combustion, in particular with the resultant steam parameters being the same.
  • the invention means that a coal-fired power station designed for combustion with air can also be operated without any problems as a CO 2 -free or low-CO 2 power station operating on the basis of the oxyfuel process with recirculated flue gas, and can be converted to or retrofitted with the oxyfuel process or oxyfuel mode.
  • the burners are then operated with a supply of pure oxygen of with >95% by volume of O 2 , or a mixture of pure oxygen and recirculated flue gas with a high CO 2 content.
  • flue gas which is created during the combustion process is fed back, that is to say recirculated, into the burner and the burner or furnace area.
  • treated and/or untreated flue gas it is possible, according to one refinement of the invention, for treated and/or untreated flue gas to be fed back in a recirculating manner to the steam generator.
  • Untreated flue gas means flue gas which is tapped off in the flue gas path after the steam generator for recirculation before any flue gas treatment is carried out in the flue gas path, for example by an electrical filter, a flue gas desulfurization installation or a flue gas drier. The process of passing through heat displacement systems or elements by means of which energy is simply extracted from the flue gas does not mean that the flue gas can then be regarded as having been treated.
  • the exemplary embodiment illustrated in FIG. 1 shows possible points and locations for tapping off untreated flue gas, provided with the reference symbols 1 , 2 and 3 .
  • the term “treated” flue gas means a treatment which changes the flue gas composition. Possible points or locations for tapping off treated flue gas for recirculation are identified by the reference symbols 4 , 5 and 6 in FIG. 1 .
  • the invention furthermore provides that an existing power station, in particular a so-called 600° C. power station, is retrofitted with the method as claimed in claim 1 or 2 .
  • the recirculation rate of the flue gas is 65% to 80%, in particular 74% to 78%.
  • a power station designed for the air mode can be operated in the oxyfuel mode with particularly minor conversion or modification effort if the flue gas is tapped off after desulfurization (DeSOx) or after a flue gas desulfurization (DeSOx) installation or a flue gas cooler, which is installed in particular additionally and/or subsequently, for recirculation, as the invention likewise provides.
  • the invention provides that a heat displacement system is installed between a suction draft and desulfurization or a desulfurization installation. This makes it possible to influence the thermal balance of the recirculating flue gas flow, as well as the temperature of the recirculated flue gas, via energy removal.
  • the power station according to the invention is, finally, distinguished in that the flue gas channel has a bypass line, which is routed in particular parallel to an air preheater (LUVO) and has a gas/gas heat exchanger arranged therein, after a denitrification (DeNOx) device in the flow direction.
  • LUVO air preheater
  • DeNOx denitrification
  • FIG. 1 shows a schematic illustration of a method and installation layout for the gas and combustion side of a steam generator
  • FIG. 2 shows a schematic outline illustration of a method layout for the gas and combustion side of a steam generator
  • FIG. 3 shows a schematic outline illustration of a further embodiment of a method layout on the gas and combustion side of a steam generator
  • FIG. 4 shows a schematic outline and section illustration of the design of a steam generator
  • FIG. 5 shows a comparison of the temperature profile over the furnace height in the radiation part of a steam generator in comparison between the air mode and the oxyfuel mode
  • FIG. 6 shows a comparison of the temperature profile in the convective part of a steam generator in comparison between the air mode and the oxyfuel mode
  • FIG. 7 shows the temperature profile of the water/steam system in the convective part of a steam generator in comparison between the air mode and the oxyfuel mode
  • FIG. 8 shows an illustration in the form of a table of the difference between various characteristic values in comparison between the oxyfuel mode and the air mode, on the one hand using metric units and on the other hand percentages,
  • FIG. 9 shows an illustration in the form of a table of the difference in the flue gas composition after the electrical filter in comparison between the air mode and the oxyfuel process
  • FIG. 10 shows a table of a comparison between the air mode and the oxyfuel mode in respect of different physical characteristics
  • FIG. 11 shows an illustration, corresponding to
  • FIG. 2 with additional details of the gas temperatures in ° C. and of the mass flows in kg/s.
  • FIGS. 1-3 allow a conventional coal-fired power station to be converted to the oxyfuel mode.
  • a method is also described, on the basis of which the oxyfuel mode can then be carried out in an optimum manner.
  • a special feature of the conversion and of the method is that normal air operation is also still possible after conversion.
  • the installation can be safely started in the air mode before switching to the oxyfuel mode, and with switching once again taking place to the air mode, which can be coped with more easily (with high efficiency) and with CO 2 emission, before shutdown, in the event of disturbances in operation, or in the event of an interruption in the CO 2 storage capability downstream from the power station.
  • FIG. 2 shows a method layout on the gas side of a coal-fired power station, on the basis and by means of which the coal-fired power station can be operated both in the air mode and in the oxyfuel mode on the burner side.
  • the combustion air is preheated after induction by the fresh-air fan 7 in a heat displacement system (WVS) 35 (WÜ3) which may be provided.
  • WVS heat displacement system
  • WÜ3 heat displacement system
  • the air is split into carrier air, other burner air, and —if present—into a mill circuit flow.
  • the carrier air is supplied upstream of the mill to a further fan (primary fan) 9 , whose pressure increase ensures that the coal is removed to the burners 10 .
  • the mill circuit flow is used for heat displacement (WÜ1 and WÜ2) from the off-gas to the feed water preheating path. This has a positive effect on the overall efficiency of the installation, because a greater heat flow of the off-gas is used, thus reducing the off-gas losses. Furthermore, it is possible to save tapped-off steam for feed water preheating.
  • the flue gas After combustion in the steam generator 11 , in addition to exchanging heat with the combustion air (LUVO), the flue gas is also subjected to catalytic denitrification 12 in order to reduce the NOx emissions, dust removal 13 and desulfurization 14 , in order to comply with the respective emission limit values.
  • catalytic denitrification 12 in order to reduce the NOx emissions, dust removal 13 and desulfurization 14 , in order to comply with the respective emission limit values.
  • the coal is burnt in the combustion area and a portion of the heat transfer takes place to the working medium steam/water in the wall heating surfaces of the steam generator (mainly by radiation).
  • a convective heat transfer takes place in the subsequent convective heating surfaces to superheater, intermediate superheater and economizer heater surfaces.
  • the flue gas which is enriched with oxygen as recirculation gas and is used as a substitute for the combustion air is therefore in one preferred embodiment tapped off after the desulfurization 14 , 15 at the point 5 or after a flue gas cooler 16 , which has to be additionally installed, at the point 6 , in which case, of course, mixtures of flue gas fed back at the points to 4 or 1 to 5 or one of these points are also possible.
  • the flue gas has a very high purity level at these points 5 and 6 (in respect of dust, SO 2 /SO 3 content) and is at a sufficiently low temperature.
  • FIG. 5 shows that the temperature profile curve 43 for the oxyfuel mode 43 provides a good match with the curve 44 for the air mode.
  • FIG. 5 shows that the temperature profile curve 43 for the oxyfuel mode 43 provides a good match with the curve 44 for the air mode.
  • the combustion side that is to say the flue gas/gas side of the steam generator 11 , is adapted because of the changed flue gas characteristics, both with respect to the heat content (density, heat capacity) and heat transfer (changed flow rates, heat transfer coefficients).
  • the aim is that the water/steam circuit should remain at least substantially unchanged.
  • the magnitude of the total amount of recirculated flue gas, the split between the various combustion gas, feed gas and process gas flows burner “air”, mill “air”, over fire “air”, curtain “air” as well as the oxygen contents of these gas flows and the total amount of excess oxygen result in new degrees of freedom which are used for adaptation of the combustion.
  • the total amount of recirculated gas is determined such that the heat transfer in the convective heating surfaces corresponds to the old design data.
  • FIG. 8 which figure lists average values of variables which characterize the heat transfer in the convective surfaces
  • this is done in the oxyfuel case with an amount of recirculated gas which causes a flue gas density which is higher by 38.5% than the air mode, a higher heat transfer (alpha) by radiation (+23%) and convection (+6.8%), a flue gas mass flow increased by 7.8% and a reduction in the mean logarithmic temperature difference by 11.2% or produces these effects.
  • the recirculation rate of the flue gas is 75.7%.
  • this value is dependent on the precise fuel characteristics and the basic design of the power station, and can assume values between 65 and 80%.
  • the recirculation rate means the proportion of the recirculated flue gas in the total amount of flue gas.
  • a burner such as this is therefore able to operate with different gas compositions and therefore offers the capability to adjust the combustion and temperature profile in a suitable manner in the oxyfuel mode such that analogous amounts of heat are transferred in the combustion chamber as in the air mode, combustion furthermore taking place with low levels of hazardous substances.
  • the proportion of the recirculated flue gas which is required for the burner in the oxyfuel mode is obtained to a first approximation from the requirement to maintain the impulse flows at the burners in the various operating modes.
  • the component 47 of the burner “air” which is used as a flow element of the combustion gas in order to remove the coal from the mill 36 (carrier gas) must also be determined corresponding to the equality of the impulse forces acting on the coal particles.
  • F SW c w ⁇ A S ⁇ 2 ⁇ ⁇ F ⁇ w F 2 2 Equation ⁇ ⁇ 3
  • F S g ⁇ ⁇ S ⁇ V S Equation ⁇ ⁇ 4
  • F A g ⁇ ⁇ F ⁇ V S Equation ⁇ ⁇ 5
  • a s , V s surface, volume of the dust grain
  • the weight forces are of equal magnitude and will not be considered any further.
  • the lift force is negligibly small, because the density difference between flue gas and dust grain is very great. This means that only the flow force need be compared.
  • Equation 2 for the impulse flow maintenance is therefore applicable and this ensures that the coal is removed.
  • the oxygen content of the burner gas flows 38 or of the burner “airs” is set such that the adiabatic combustion temperature remains virtually constant.
  • the design value for the combustion stoichiometry must also be complied with approximately in the oxyfuel case. Since the risk of the formation of thermal nitrogen oxide is reduced by the lack of nitrogen from the air, slightly increased stoichiometries may also be used, however, to set the level of the combustion area temperatures.
  • oxygen contents of the transport gas and of the other gas flows should differ by up to 15% by mass depending on the fuel characteristics, in particular the capability to ignite the coal. This allows the over fire speed in the flame to be controlled in order to allow the temperature profiles in the combustion chamber 25 of the steam generator 11 to be similar to those of the air combustion.
  • the temperature profile and temperature level are responsible for the heat transfer, which dominates in the combustion area 18 of the steam generator 11 , by radiation in this area, which is the governing design criterion in order to comply with the required combustion chamber final temperature and the amount of heat transferred to the water, as the working medium, in the combustion chamber walls.
  • FIG. 2 does not illustrate the so-called curtain or side-gas injection which is used in some power stations in order to reduce the risk of reducing areas in the vicinity of the combustion chamber walls, and to avoid the risk of increased wall corrosion.
  • its proportion in the total amount of gas or “air” supplied in the area of the burner 10 remains low without any change, in order to still provide the impulse flow which is necessary for the penetration depth and coverage of the entire wall.
  • its oxygen content in the oxyfuel mode is increased by up to 20 percentage points in comparison to the pure air mode, in order to provide effective protection against the higher CO contents (in this part of the combustion area) occur because of the Boudouard equilibrium and the high CO 2 contents.
  • the proportion of the recirculated flue gas which is added in the upper part of the combustion chamber 25 of the steam generator 11 as over fire air (OFA) 37 is governed by the fixing of the other gas flows.
  • the oxygen content in the over fire air (OFA) is determined from the overall stoichiometry, that is to say from the excess oxygen which is required overall for reliable combustion of all the coal components and so as to minimize the CO content—the stoichiometry factor in the exemplary embodiment is 1.17.
  • it can assume values between 1.1 and 1.25 for the air mode, but should be as low as possible in the oxyfuel case in order to avoid further dilution of the CO 2 by excess oxygen.
  • the purging and/or barrier gas (air) which is used nowadays in/on rotating parts of the coal mills 36 associated with the power station is replaced by CO 2 during the conversion to the oxyfuel mode.
  • the air preheater 8 is still required in the illustrated exemplary embodiment.
  • the recirculated amount of flue gas fed back cannot, however, absorb the total amount of heat that is required, because oxygen is still lacking, since the oxygen is not mixed with the flue gas before the air preheater 8 .
  • this is also undesirable since conventional regenerative air preheaters in the design case for air operation have unavoidable leakage in the direction of the flue gas between the two gas flows (off-gas and recirculated flue gas) which flow in opposite directions. Oxygen losses (and a greater energy consumption) as well as reduced CO 2 purity would therefore be expected in the oxyfuel mode.
  • a gas/gas heat exchanger 19 in order to preheat the oxygen is installed together with a control valve to split the flue gas to be cooled down, in the bypass to the air preheater 8 for the oxyfuel mode.
  • the old operating state can therefore still be selected by disconnecting the oxygen preheater by closing the bypass by closing the control valve.
  • the sealing from the environment can be improved with greater or lesser complexity since there is still the reduced pressure at this point on the flue-gas side.
  • the steam generator 11 In order to prevent more environmental air from entering the steam generator 11 in the area of the funnel 41 of the steam generator 11 , it is in any case advantageous during the conversion process for the steam generator 11 to be equipped for wet ash removal if dry ash removal is installed in the existing installation. In the case of wet ash removal, adequate sealing is ensured in any case by the sealing of the water-filled trough with respect to the steam generator walls.
  • shut-off devices to the ash removal system of the electrical filter 13 are designed to be gas-tight (for example gas-tight bucket feed gates). To entirely prevent this leakage flow of leakage air in the system CO 2 should be applied to the shut-off devices as a sealing barrier gas.
  • the absorbent should be changed from limestone (CaCO3) to quicklime (CaO) since the CO 2 release which is required to dissolve the limestone in the dissolving process is impeded by the saturation of the wash suspension with CO 2 .
  • the absorbent mixing systems must be appropriately modified for this.
  • flue gas desulfurization is carried out using the methods that are normally used nowadays, the calcium sulfide which is created in the solution is oxidized by air injection to form calcium sulfate, this method step is also modified during the conversion/modification to the oxyfuel mode.
  • the oxidation in an installation designed for the air mode is carried out by injecting air into the sump of a spray tower, desired oxygen would once again not be introduced when using air without a hardware change. Pure oxygen must not be injected since, on the one hand, the production of this oxygen would result in a correspondingly greater energy requirement for the air separation unit (ASU) 20 .
  • the need for excess oxygen leads to the CO 2 provided for storage being of lower purity.
  • the desulfurization is converted to external oxidation by fitting an external stirring container 39 ( FIG. 3 ), thus preventing N 2 and O 2 from being introduced into the system.
  • the desulfurization installations now being designed for the laws applicable in Germany achieve an SO 2 value of ⁇ 200 mg/Nm 3 (dry, with the current oxygen content)
  • the desulfurization must be improved in order to prevent corrosion problems in downstream process steps (compression, transport to the storage location).
  • the fresh-air fan 7 and the fuel/air channels are also not designed for increased SO 2 /SO 3 contents on conversion/modification to oxyfuel operation.
  • An increase in separation can be achieved in two ways.
  • the existing DeSOx can be improved within limits by increasing the ratio of liquid circulation to flue gas flow, while on the other hand a further spray level can be retrofitted if sufficient space is available in the head area of the spray tower. Retrofitting a tray or the addition of acids which promote solution likewise improves the desulfurization.
  • the flue gas desulfurization installation (REA) 15 is followed by a flue gas condensation drier 21 . This cools the flue gases further in order to achieve the required water contents of ⁇ 3% (for recirculation).
  • the liquid nitrogen from the air separation unit 20 is also used for this purpose. After drying, the flue gas flow is split, and the majority is recirculated 22 , 23 . The flow element which is intended to be supplied to the compressor 24 is pased on for further purification.
  • the flue gases which have been purified in this way are supplied to the compressor station 24 .
  • the residues of O 2 and N 2 which are still present in the gas flow are removed from the liquefied CO 2 by a phase separator, since these gases are not liquefied in these conditions.
  • the CO 2 is now available for storage and further transport.
  • Liquid nitrogen produced in the air separation unit (ASU) 20 can be used in conjunction with a cooling water flow for this purpose (if oxygen and nitrogen as the products of the air separation are in liquid form).
  • the nitrogen is first of all used in the cooling system of the multistage CO 2 compressor 24 , in order to minimize the energy consumption of the compressor.
  • the energy transferred to the “superheated” nitrogen is then optionally partially recovered by means of an expansion turbine, in which process the nitrogen temperature falls again.
  • the mass flow of nitrogen is then used via coupling heat exchangers both for cooling the NaOH recirculation and for cooling the flue gas condensation drier 21 arranged downstream from the flue gas desulfurization installation (REA) 15 , where cooling water flows are added to it.
  • the nitrogen can then optionally once again be passed via expansion turbines for energy recovery, and fed back into the environment via a stack.
  • the described procedure for designing the combustion process of an oxyfuel steam generator can also be iteratively coupled to the normal design of the convective heating surfaces of a steam generator and can be used for cost-optimized design of a new installation by reducing the size of the heating surfaces while at the same time increasing the flue gas speed by reducing the cross section of the combustion chamber. From the flow mechanics point of view, it is now necessary to depart from a direct analogy with the impulse relationships: the case of air combustion can then be designed (for the same flow speed which is limiting under erosion viewpoints) with a correspondingly reduced power (partial load for starting/shut-down processes and operating disturbances).
  • the following explanations likewise relate to a conversion concept for a coal-fired power station.
  • the options for implementation of a CO 2 -free power station in which the CO 2 is separated and stored is discussed, and what the advantages and disadvantages are.
  • the state of research relating to the oxyfuel process is described briefly. After a discussion of possible variants of the oxyfuel process, two variants are selected. These are analyzed in terms of the conversion measures required to the power station components: combustion gas system, flue gas cleaning installation, mills, burners and steam generators. Heat engineering calculations relating to heat transfer in the steam generator indicate that the required steam parameters are achieved without conversion of the steam generator heating surfaces.
  • the aim of the oxyfuel process is to achieve as high a CO 2 concentration as possible in the flue gas in order to save the energy-consuming CO 2 washing of the “post combustion process”.
  • the energy consumption can be reduced if the CO 2 has a high concentration.
  • the compressor power is then applied only to the CO 2 and not to the impurities as well.
  • the nitrogen component of approximately 78% by volume prevents high CO 2 enrichment in the flue gas. If, in contrast, to this, pure oxygen is used for combustion, considerably higher CO 2 contents of up to 80% by volume can be achieved during combustion using dry brown coal, and more than 90% by volume when using hard coal. These values may fluctuate depending on the combustion conditions and the coal composition. Nevertheless, they are good preconditions for separation and storage of CO 2 .
  • the heat transfer in the steam generator 11 takes place by convection or by radiation.
  • a changed flue gas composition results in changed values of heat capacity, viscosity and thermal conductivity as well as flue gas density, as shown in FIG. 8 .
  • the flow speed of the flue gas is therefore also changed.
  • the heat transfer ratios can therefore be matched by adaptation of the molar recirculation ratio.
  • Molar recirculation ratios of 3.25 are determined for the moist feedback of the flue gas (removed at location 5 ) and 2.6 for feedback at location 6 after the flue gas drying 21 . As the recirculation ratio rises, the heat transfer by radiation decreases, because the flame temperatures are lower.
  • the radiation heat transfer varies in particular as a function of the composition and the temperature of the gas.
  • the most important ways include the oxygen content in the combustion gas and the proportion of the recirculated gas mass flow in the flue gas mass flow that is produced overall.
  • the high proportion of nitrogen in the flue gas in the case of air combustion is replaced by CO 2 in the oxyfuel process.
  • the flue gas contains a greater or lesser amount of water.
  • CO 2 and H 2 O are not diathermic in the same way as N 2 and O 2 , but themselves absorb and emit heat radiation depending on the gas temperature.
  • the higher heat capacity of the combustion gas primarily caused by CO 2 and water, changes important flame characteristics.
  • Emissitivity of the flame in the oxyfuel mode and in the air mode is similar. It depends in particular on the coal, the fly ash, soot particles in the flame, but not on the CO 2 concentration.
  • the ignition delay is calculated by dividing the movement distance over which the coal particles travel before ignition by the particle speed.
  • the ignition delay rises when
  • the ignition delay is greater than in a nitrogen-rich atmosphere (air operation), given the same oxygen content.
  • the gas In order to achieve the same ignition delay as with air combustion, the gas must consist of 30% by volume of oxygen and 70% by volume of CO 2 in the oxyfuel gas.
  • FIG. 4 shows, various heating surfaces, which differ in terms of the heat transfer method, exist in a steam generator 11 .
  • Heat transfer by radiation is dominant in the combustion chamber 25 and in the radiation areas 26 and 27 , and these are therefore referred to as radiation heating surfaces.
  • the combustion chamber 25 , the radiation areas 26 and 27 are together referred to as the combustion area 18 .
  • the heat transfer in superheater heating surfaces 28 and 29 and intermediate superheater heating surfaces 30 and 31 as well as the economizer heating surface 32 takes place mainly by convection, as a result of which these heating surfaces are referred to as convective heating surfaces.
  • the convective part of the steam generator 11 represents the totality of all convective heating surfaces.
  • the supporting tube bulkhead 49 has the special feature of also having a large radiation component as a convective heating surface. This can be explained by its position as the first bundle heating surface above the combustion area 18 .
  • the final stages of the HP (high-pressure) and MP (medium-pressure) parts and of the economizer heating surface have flow passing through them in the sense of a parallel-flow device. In the final stages, this is used to reduce the corrosion tendency by means of lower material temperatures, and to protect the turbine against temperature fluctuations.
  • the economizer heating surface 32 is intended to guarantee that any steam bubbles that may occur are removed.
  • the aim is to convert a 600° C. or 700° C. power station designed for air operation to the oxyfuel process. This means that the steam generator 11 must be able to supply the turbine with the required steam parameters in both the air mode and the oxyfuel mode. The aim is to do this without any modifications to the steam generator heating surfaces, mills and burners.
  • the critical criterion for the economy of the oxyfuel process is to achieve a high CO 2 content in the off-gas. Only considerable energy savings in the CO 2 concentration and compression justify the high-energy oxygen generation as an additional process in comparison to simple flue gas washing with a washing agent (for example monoethylamine). Any air leakages which enter in addition to the purging air and barrier air that is supplied counteract this aim, and must therefore be reduced to a minimum.
  • a washing agent for example monoethylamine
  • FIG. 1 shows, it is possible to tap off flue gas for flue gas circulation at the following points:
  • Neither existing regenerative air preheaters 8 nor a heat displacement system 16 before the flue gas desulfurization installation 14 , 15 are required in the oxyfuel mode since, when a large proportion of the flue gas is tapped off before the air preheater 8 , there is no substance flow to be cooled down or heated.
  • An existing electrical filter 13 and the flue gas desulfurization installation 15 are then overdesigned for the oxyfuel mode.
  • the flow ratios can be adapted, if necessary, for optimum dust separation and desulfurization rate by shutting down individual electrical filter passages or washer levels.
  • the drier 21 which is provided only for the oxyfuel mode can in this case be designed for small volume flows.
  • the oxygen flow is then heated in an additional heat exchanger 33 , which is arranged before the electrical filter 13 , where the flue gas temperature is about 380° C.
  • the electrical filter 13 When the flue gas is recirculated from the point 4 , behind the electrical filter 13 , the flue gas is enriched with sulfur oxides and water. The dust load for flue gas channels and fans decreases considerably.
  • the electrical filter 13 is then designed and constructed such that it can be used both for the air mode and for the oxyfuel mode.
  • the flue gas is now further enriched only with water since large amounts of the sulfur are removed in the flue gas desulfurization installation 14 , 15 . This reduces the risk of corrosion caused by sulfuric acid.
  • the quench effect in the flue gas desulfurization installation 15 cools the flue gas by partial vaporization of the absorber suspension. In this case, the water content and the outlet temperature of the flue gas are set as a function of the saturation temperature.
  • the flue gas When the flue gas is recirculated from the point 6 , behind the drier 21 , the flue gas is sucked back or fed back (recirculated) with all the dust removed, after desulfurization and dried. With this flue gas quality, the fresh-air fan can be used as recirculation fan. All the heat exchangers and flue gas treatment components used in the air mode can be operated in the oxyfuel mode without any change from the air mode. However, the entire flue gas mass flow is passed via the drier 21 which means that this must be designed to be appropriately large in order to be able to carry away large heat flows.
  • a flow element which has been passed through all the flue gas treatment components is correspondingly purified, as a result of which the concentrations of hazardous substances such as dust, water and sulfur oxides are reduced.
  • a second flow element can then be recirculated very close to the steam generator 11 , for example at the point 1 , at a high energy level. There is therefore no need for this flue gas flow element to be cooled down and heated up again later.
  • Conversion or modification to the oxyfuel process changes the recirculation mass flow which, together with the mixed-in oxygen mass flow and with the flue gas temperature profile unchanged, primarily influences the flow speeds in and on the heating surfaces.
  • the higher density of CO 2 (oxyfuel mode) in comparison to N 2 (air mode) results in a slower flow for the same mass flow.
  • the flow speed of the flue gas plays an important role, in addition to physical characteristics such as viscosity, thermal conductivity and heat capacity, in the heat transfer from the flue gas to the heating surface. The required steam parameters are achieved, despite the changes in the heat transfer conditions.
  • the control system introduces as much fuel as is required, and for as long as is required, to reach the high-pressure (HP) outlet mass flow, and the temperature is controlled by enthalpy control and injection.
  • the medium-pressure (MP) outlet temperature can be influenced by the magnitude, that is to say the amount, of the recirculation mass flow which ensures advantageous flow speeds for heat transfer.
  • the excess oxygen ⁇ 02 means the ratio of the oxygen flow m 02 supplied to the stoichiometrically required oxygen flow m O2,min .
  • the combustion air mass flow m air required for this is calculated using the equation
  • m . air m . O ⁇ ⁇ 2 , min ⁇ 100 21 ⁇ ⁇ O ⁇ ⁇ 2 .
  • the excess air then corresponds to the excess oxygen.
  • the numerator contains all the oxygen mass flows (combustion gas, feed gas, process gas) supplied for combustion.
  • the denominator contains the stoichiometric oxygen requirement, which is calculated from the reaction of the coal components C, H, O and S to form CO 2 , H 2 O and SO 2 .
  • FIG. 9 A comparison of the flue gas compositions that occur between the air mode and the oxyfuel mode with flow gas circulation after the electrical filter 13 at the point 4 and after the drier 21 at the point 6 is shown in FIG. 9 .
  • FIG. 10 shows the higher density of the flue gas in the oxyfuel process (+23.9%+33.3%).
  • the heat capacity, dynamic viscosity and thermal conductivity of the flue gases vary only slightly in comparison to the air mode when the flue gas is taken off at the point 6 .
  • the higher heat capacity and the higher thermal conductivity at the point 4 in comparison to the point 6 can be explained by the water content of the flue gas being even higher there.
  • the fuel mass flow and the recirculation mass flow are adapted. Because of the higher density of the flue gas in the oxyfuel process, the flow in the convective part is slowed down, despite the flue gas mass flow being higher.
  • the improved heat transfer by radiation in the area of the convective heating surfaces by more than 39% is significant. In the case of the oxyfuel process with recirculation at the points 4 and 6 , this is because of the high CO 2 concentration, and at the point 4 , it is because of the increased water concentration.
  • the heat transfer coefficient k is increased by the greater proportion of the radiation in the heat transfer in the convective part.
  • the heat flow transferred in the convective part is increased.
  • the heat transfer in the convective part also depends on the heat transfer in the radiation heating surfaces. This is because of the conditional flue gas and water/steam temperatures.
  • the radiation heating surfaces are located before the convective heating surfaces 28 to 32 , 49 along the flue gas path in the combustion chamber 25 and the radiation areas 26 , 27 .
  • the economizer heating surface 32 With the economizer heating surface 32 , the water first of all flows through a convective heating surface, followed by the radiation heating surfaces for vaporization, and finally once again convective heating surfaces for superheating the steam.
  • the flue gas will be considerably cooler because of the higher heat capacity in the oxyfuel process in the combustion chamber 25 and, at the end before the air precooler, will be somewhat hotter than in the case of the air process. It is therefore not absolutely essential to reach the adiabatic combustion temperature of the air process.
  • a change in the warming-up ranges in the superheaters and intermediate superheater heating surfaces should be observed.
  • the warming-up ranges are higher than in the air process in the oxyfuel process using the circulation points 4 and 6 .
  • only the heating surface 39 reaches a greater warming-up range in the medium-pressure heating surfaces.
  • FIGS. 2 and 11 illustrate the feed back, with FIG. 11 additionally showing the temperature and mass flow details of the fed-back flue gas flow, of the oxygen supplied from the oxygen preheater, as well as thermal energy flows.
  • the components to be converted or to be added in comparison to an air mode are shown on a grey background.
  • the required pressure increase in order to overcome the flow resistances and in order to produce a pressure gradient in the air preheater 8 and in the gas channels is produced by a recirculation fan 48 , 48 a , 48 b.
  • the temperature on the recirculation side is higher in the flow direction before the air preheater (LUVO) 8 than on the flue gas side in the flow direction behind the air preheater (LUVO) 8 .
  • the flue gas can therefore not be cooled down to a lower temperature, without any further measures, in the air preheater (LUVO) 8 before entering the electrical filter 13 .
  • the cooling down in the air preheater (LUVO) 8 on the flue gas side is therefore controlled via the heat exchanger 35 (WÜ3), 16 by setting a temperature on the recirculation side before the air preheater (LUVO) 8 . Furthermore, the heat transfer in the air preheater (LUVO) 8 is governed by the mass flows. In order to achieve the same flue gas temperatures at the inlet to the flue gas desulfurization installation (REA) 15 as in the air process, the flue gas is cooled down further after the suction draft 17 .
  • the flue gas desulfurization installation 15 designed for the air mode is normally overdesigned for the oxyfuel mode, and adaptation to the reduced volume flow and the higher sulfur concentration may be necessary. This can be done by a design in which a relatively large portion of the washer can be shut down in the oxyfuel mode. Appropriate required flow speeds are then set in the smaller part that is used.
  • the entire flue gas desulfurization installation (REA) 15 would be used in the air mode.
  • the air supplied in the air process in order to improve the reaction must be replaced in the oxyfuel mode by external oxygen injection (external oxidation) 39 , in order not to reduce the CO 2 concentration in the flue gas.
  • the flow speed in the oxyfuel mode is reduced in comparison to the air mode because of the increased density of the flue gas.
  • the heat transfer on the flue gas side is changed because the physical characteristics are different. A reduced heat flow is transferred.
  • the mill circulating flow can be increased by about 60%. This then results in negative feedbacks to the bleeds on the turbine, and in a positive increase in the heat-absorbing mass flow in the air preheater (LUVO).
  • the hot-gas temperature required for coal drying can be determined. Cold air is admixed before the mill in the air process, in order to control this temperature. Instead of this, recirculated flue gas containing CO 2 is used for a high CO 2 concentration in the off gas in the oxyfuel process. Correspondingly cold flue gas is tapped off behind the flue gas drier and condenser 21 at about 25° C. After increasing the pressure and heating, it is mixed in the required proportion before the mills 36 at 30° C., by means of an additional fan.
  • the flue gas can absorb the fuel moisture and the conventional sifter temperature in the mills 36 of 90° C. need not be increased for saturation reasons.
  • the dew-point temperature of the sulfuric acid is undershot in the mills 36 and likewise in the oxygen preheater, in the heat exchangers and in the mill circuit fan, as well as the corresponding associated gas channels.
  • the surfaces of these components may be coated with plastic, if required.
  • this additional layer has the disadvantages that it impedes heat transport and offers scarcely any resistance against erosion.
  • the flue gas recirculation mass flow has an important influence on the flow speed of the flue gases in the convective part of the steam generator and on the adiabatic combustion temperature.
  • a reduction in the flue gas mass flow at the burner acts like an increase in the oxygen content on the processes in the combustion chamber 25 and in the combustion area 18 .
  • FIGS. 1 , 2 and 11 show the process layouts in a flue gas circulation at the point 6 .
  • the flue gases are tapped off behind the flue gas drier 21 , and are fed back. Since the flue gas is cooled down to 25° C. in the drier 21 and a major level of dust removal and desulfurization are carried out, the fresh-air fan 7 can also be used as a recirculation fan.
  • the recirculated flue gas is heated in the heat displacement system (WÜ3) 35 to 107° C.
  • This temperature has an influence on the cooling down of the flue gas in the air preheater 8 , which should be done at most to above the sulfuric acid dew point.
  • the heat displacement system (WÜ3) 35 is no longer in the form of a regenerative heat exchanger in the oxyfuel mode, because this does not allow the desired media temperatures to be achieved.
  • the heat transfer in the air preheater (LUVO) 8 is controlled by the distribution of the flue gas mass flow between the air preheater (LUVO) 8 and the air preheater (LUVO) bypass 34 .
  • the inlet temperature into the flue gas desulfurization installation (REA) 14 , 15 is predetermined by the heat flow which can be transferred to the recirculated flue gas in the heat displacement system (WÜ3) 35 , 16 , without any negative influence on the cooling down of the flue gas in the air preheater (LUVO) 8 .
  • the flue gas in the flue gas desulfurization installation (REA) 14 , 15 is 12% warmer than in the air process.
  • the adiabatic combustion temperature rises because a reduced flue gas mass flow has to be heated at the burner. This results in a greater heat flow being absorbed in the vaporizer.
  • the reduced flue gas mass flow is cooled down more quickly in the convective part, as a result of which the flue gas after the intermediate superheater heating surfaces 31 is cooler than in the air mode.
  • the steam outlet temperature in the HP part is 17 K higher than in the air mode. This is probably because of the increased heat absorption in the vaporizer.
  • the MP part of the steam generator 11 consisting of pure heating surfaces, in contrast does not reach the required warming-up range, as a result of which the temperature before the turbine is 17 K lower than in the air mode.
  • the recirculated mass flow is reduced by 20% and the conditions of impulse maintenance and oxygen content in the carrier gas are maintained, then the recirculated gas mass flow is furthermore not sufficient for impulse maintenance in the secondary gas. Less flue gas is then passed via the secondary gas, and no more is passed via the upper gas nozzles into the steam generator.
  • the fuel mass flow is now set such that the required HP outlet mass flow is achieved. This is linked with adapting the oxygen mass flow in order to maintain the desired excess oxygen of 1.17.
  • the water mass flow injected for cooling before the intermediate superheater heating surfaces 31 is used to control the MP outlet temperature. This reduces the fuel mass flow by 2.5% in comparison to the optimum state in the air mode. In consequence, the adiabatic combustion temperature rises less severely and a somewhat reduced heat flow is absorbed by the radiation heating surfaces.
  • the flue gas cools down more quickly due to the reduced heat flow introduced, and is already cooler behind the superheater heating surfaces 29 than in the optimum case in the air mode. Together with the reduced flue gas mass flow, this affects the heat transfer in the MP part. Despite reducing the injected cooling mass flow by 100%, the required outlet temperature on the intermediate superheater heating surfaces 31 cannot be achieved.
  • the recirculated flue gas mass flow is increased by 20% and the conditions for impulse maintenance and oxygen content in the carrier gas and secondary gas are maintained, and if, furthermore, the upper gas nozzles pass excess sucked-back flue gas into the steam generator, the required HP outlet mass flow can be achieved by adaptation of the fuel mass flow.
  • the excess oxygen of 1.17 should in this case be retained.
  • the water mass flow injected for cooling before the intermediate superheater heating surfaces 31 is used to control the MP outlet temperature.
  • the steam generator control reacts to the steam temperature not being achieved at the outlet of the HP part by increasing the fuel mass flow by 2.5%. This results in the adiabatic combustion temperature rising and thus also the heat absorbed in the combustion chamber and the bulkhead heating surface.
  • the somewhat greater volume flow as a result of the increased flue gas temperatures fuels better heat transfer in the convective part of the steam generator.
  • the MP part is affected negatively by this.
  • the warming-up ranges of the heating surfaces before the water injection are enlarged, which can be compensated for by quadrupling the injected water mass flow.
  • the reduction in the radiation exchange coefficient in the combustion chamber 18 is reduced by 30% from 1.636 to 1.145 and the fuel, oxygen and recirculation mass flows are kept constant, the reduction in the radiation exchange coefficient also causes the heat absorbed in the combustion chamber 18 to fall.
  • the steam at the separator is 25 K cooler.
  • the reduced heat absorption in the vaporizer is virtually completely compensated for by the convective heating surfaces of the HP part.
  • the effects of a change in the radiation exchange coefficient C of the combustion chamber 18 can be compensated for by adaptation of the fuel (HP outlet) and recirculation (MP outlet) mass flows.
  • the excess oxygen is kept constant during this process.
  • a reduced radiation exchange coefficient C can be compensated for by a minimal reduction of the fuel mass flow and an increase of the recirculation mass flow. It is more difficult to compensate for the effects of a varied recirculation mass flow. It is therefore more important to accurately set the circulation mass flow during generator operation.
  • the required steam parameters can be achieved in the oxyfuel process as follows, without any changes to the steam generator heating surfaces.
  • the heat transfer can be adapted by adjusting the fuel, oxygen and recirculation mass flows. However, an increase in the fuel mass flow reduces the overall efficiency, and should therefore be avoided. If, in contrast, variable combustion gas compensations are used to influence the heat transfer in the steam generator, this has a much more advantageous effect.
  • the possibility of mixing in the oxygen into the primary, secondary and upper gases and therefore of adjusting the oxygen component as required provides the oxyfuel process with an additional degree of freedom for controlling the flame temperatures.
  • Increased NO x concentrations are created in an air process without any steps by the nitrogen in the air and high combustion temperatures.
  • the nitrogen component introduced in the combustion gas is less than 7%, as a result of which virtually only fuel NO x can still be formed.
  • the creation of the nitrogen oxides is dependent mainly on the combusted coal mass flow and its composition.
  • compositions and mass flows of the burner gases and of the upper gas can be varied in order to optimally adapt the heat absorption in the combustion area and convective part of the steam generator to the operating conditions. For example, during operation of the steam generator, the reduced heat absorption in the vaporizer resulting from dirt can be compensated for by adaptation of the recirculation mass flow.
  • the efficiency is reduced by the additional electrical consumption for the air separation 20 and the CO 2 compression by about 10%.
  • the efficiency losses are small in comparison to the flue gas washing (MEA).

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100101462A1 (en) * 2008-10-27 2010-04-29 Hitachi, Ltd. Oxyfuel Boiler and a Method of Controlling the Same
US20110011315A1 (en) * 2009-07-14 2011-01-20 Hitachi, Ltd. Oxyfuel Boiler and Control Method for Oxyfuel Boiler
US20110076216A1 (en) * 2009-09-30 2011-03-31 Hitachi, Ltd. Carbon Dioxide Capture Power Generation System
EP2489423A1 (fr) * 2011-01-28 2012-08-22 Korea Institute of Energy Research Appareil de traitement de gaz d'échappement et procédé de traitement pour procédé de capture de dioxyde de carbone
US20120272626A1 (en) * 2009-11-25 2012-11-01 Babcock-Hitachi Kabushiki Kaisha Exhaust gas treatment device for an oxygen combustion system
US20130055937A1 (en) * 2010-05-18 2013-03-07 Babcock-Hitachi Kabushiki Kaisha Flue gas desulfurization device, combustion system and combustion method
US20130092062A1 (en) * 2010-06-16 2013-04-18 Masahiko Matsuda Combustion system
US20130152595A1 (en) * 2011-12-20 2013-06-20 Alexander Alekseev Process for the enhancement of power plant with co2 capture and system for realization of the process
US20140116358A1 (en) * 2012-10-26 2014-05-01 Alstom Technology Ltd Method of treating a carbon dioxide rich flue gas and a flue gas treatment system
US8789479B2 (en) 2009-11-09 2014-07-29 Ihi Corporation Oxygen mixer for oxygen combustion boiler
US20140245270A1 (en) * 2013-02-26 2014-08-28 Red Hat, Inc. Systems and methods for providing context simulation
US9140145B1 (en) * 2011-08-11 2015-09-22 Sandia Corporation PH adjustment of power plant cooling water with flue gas/fly ash
US20170114995A1 (en) * 2014-03-10 2017-04-27 Integrated Test & Measurement Boiler system controlling fuel to a furnace based on temperature of a structure in a superheater section
CN112131727A (zh) * 2020-09-10 2020-12-25 华北电力科学研究院有限责任公司 一种锅炉热效率评估方法、装置及设备
CN113339831A (zh) * 2021-06-02 2021-09-03 西安热工研究院有限公司 一种利用工业供汽蒸汽余热加热烟气的系统及工作方法
CN116362164A (zh) * 2023-06-02 2023-06-30 华北电力科学研究院有限责任公司 空气预热器堵塞状况确定方法及装置

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JP5331648B2 (ja) * 2009-10-22 2013-10-30 株式会社日立製作所 微粉炭ボイラの改造方法
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DE102010030909A1 (de) * 2010-03-31 2011-10-06 Hitachi Power Europe Gmbh Verfahren zur Wärmerückintegration aus einem Rauchgasstrom gewonnener thermischer Energie
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US20120125240A1 (en) * 2010-11-22 2012-05-24 Alstom Technology Ltd. System and method of managing energy utilized in a flue gas processing system
CN102278734A (zh) * 2011-05-27 2011-12-14 开平太平洋绝缘材料有限公司 一种工业燃煤锅炉的余热利用装置
USRE48040E1 (en) 2011-09-23 2020-06-09 The University Of Newcastle Integrated chemical looping air separation in large-scale oxy-fuel plants
EP2584256B1 (fr) * 2011-10-17 2015-01-28 Alstom Technology Ltd Préchauffage de l'oxygène dans un système de combustion à oxy-gaz
DE102013001440A1 (de) * 2013-01-29 2014-07-31 Rwe Power Aktiengesellschaft Verfahren zur Regelung der Rauchgastemperatur an einem mit fossilen Brennstoffen gefeuerten Dampferzeuger
AT14471U1 (de) * 2014-03-06 2015-11-15 Lasco Heutechnik Gmbh Feuerungsanlage
CN107575190B (zh) * 2017-09-25 2018-08-24 中国石油大学(华东) 一种基于最优烟气co2富集率开采稠油油藏的ccus系统及其工作方法
DE102018100712A1 (de) 2018-01-15 2019-07-18 Deutsches Zentrum für Luft- und Raumfahrt e.V. Dampfkraftwerk und Verfahren zum Betreiben eines Dampfkraftwerks

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3356075A (en) * 1965-10-12 1967-12-05 Combustion Eng Method of pulverized coal firing a steam generator and controlling steam temperature
US4479355A (en) * 1983-02-25 1984-10-30 Exxon Research & Engineering Co. Power plant integrating coal-fired steam boiler with air turbine
US4792440A (en) * 1985-11-28 1988-12-20 Aalborg Vaerft A/S Process for desulphurization of flue gas
US5474751A (en) * 1992-02-14 1995-12-12 Siemens Aktiengesellschaft Method and apparatus for reducing the nitrogen oxides in flue gas
US6202574B1 (en) * 1999-07-09 2001-03-20 Abb Alstom Power Inc. Combustion method and apparatus for producing a carbon dioxide end product
US6418865B2 (en) * 1999-06-10 2002-07-16 American Air Liquide Method for operating a boiler using oxygen-enriched oxidants
US6505567B1 (en) * 2001-11-26 2003-01-14 Alstom (Switzerland) Ltd Oxygen fired circulating fluidized bed steam generator
US20060099902A1 (en) * 2002-09-09 2006-05-11 Hirofumi Kikkawa Exhaust smoke-processing system
US7320288B2 (en) * 2002-02-15 2008-01-22 American Air Liquide, Inc. Steam-generating combustion system and method for emission control using oxygen enhancement
US20080076080A1 (en) * 2006-09-22 2008-03-27 Tailai Hu Method and apparatus for optimizing high fgr rate combustion with laser-based diagnostic technology

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8038773B2 (en) * 2005-12-28 2011-10-18 Jupiter Oxygen Corporation Integrated capture of fossil fuel gas pollutants including CO2 with energy recovery
WO2008141412A1 (fr) * 2007-05-18 2008-11-27 Her Majesty The Queen In Right Of Canada As Represented By The Minister Of Natural Resources Procédé de combustion de charbon à l'aide d'oxygène dans un courant de gaz de combustion recyclé pour une capture de dioxyde de carbone

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3356075A (en) * 1965-10-12 1967-12-05 Combustion Eng Method of pulverized coal firing a steam generator and controlling steam temperature
US4479355A (en) * 1983-02-25 1984-10-30 Exxon Research & Engineering Co. Power plant integrating coal-fired steam boiler with air turbine
US4792440A (en) * 1985-11-28 1988-12-20 Aalborg Vaerft A/S Process for desulphurization of flue gas
US5474751A (en) * 1992-02-14 1995-12-12 Siemens Aktiengesellschaft Method and apparatus for reducing the nitrogen oxides in flue gas
US6418865B2 (en) * 1999-06-10 2002-07-16 American Air Liquide Method for operating a boiler using oxygen-enriched oxidants
US6202574B1 (en) * 1999-07-09 2001-03-20 Abb Alstom Power Inc. Combustion method and apparatus for producing a carbon dioxide end product
US6505567B1 (en) * 2001-11-26 2003-01-14 Alstom (Switzerland) Ltd Oxygen fired circulating fluidized bed steam generator
US7320288B2 (en) * 2002-02-15 2008-01-22 American Air Liquide, Inc. Steam-generating combustion system and method for emission control using oxygen enhancement
US20060099902A1 (en) * 2002-09-09 2006-05-11 Hirofumi Kikkawa Exhaust smoke-processing system
US20080076080A1 (en) * 2006-09-22 2008-03-27 Tailai Hu Method and apparatus for optimizing high fgr rate combustion with laser-based diagnostic technology

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Wang, L. K. et al.; Handbook of Environmental Engineering, Volume 6: Biosolids Treatemnt Process, The Humama Press Inc., pg. 210. *

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8413596B2 (en) 2008-10-27 2013-04-09 Hitachi, Ltd. Oxyfuel boiler and a method of controlling the same
US20100101462A1 (en) * 2008-10-27 2010-04-29 Hitachi, Ltd. Oxyfuel Boiler and a Method of Controlling the Same
US20110011315A1 (en) * 2009-07-14 2011-01-20 Hitachi, Ltd. Oxyfuel Boiler and Control Method for Oxyfuel Boiler
US8500881B2 (en) 2009-09-30 2013-08-06 Hitachi, Ltd. Carbon dioxide capture power generation system
US20110076216A1 (en) * 2009-09-30 2011-03-31 Hitachi, Ltd. Carbon Dioxide Capture Power Generation System
US8789479B2 (en) 2009-11-09 2014-07-29 Ihi Corporation Oxygen mixer for oxygen combustion boiler
US20120272626A1 (en) * 2009-11-25 2012-11-01 Babcock-Hitachi Kabushiki Kaisha Exhaust gas treatment device for an oxygen combustion system
US8778041B2 (en) * 2009-11-25 2014-07-15 Babcock-Hitachi Kabushiki Kaisha Exhaust gas treatment device for an oxygen combustion system
US20130055937A1 (en) * 2010-05-18 2013-03-07 Babcock-Hitachi Kabushiki Kaisha Flue gas desulfurization device, combustion system and combustion method
US20130092062A1 (en) * 2010-06-16 2013-04-18 Masahiko Matsuda Combustion system
EP2489423A1 (fr) * 2011-01-28 2012-08-22 Korea Institute of Energy Research Appareil de traitement de gaz d'échappement et procédé de traitement pour procédé de capture de dioxyde de carbone
US9140145B1 (en) * 2011-08-11 2015-09-22 Sandia Corporation PH adjustment of power plant cooling water with flue gas/fly ash
US20130152595A1 (en) * 2011-12-20 2013-06-20 Alexander Alekseev Process for the enhancement of power plant with co2 capture and system for realization of the process
US20140116358A1 (en) * 2012-10-26 2014-05-01 Alstom Technology Ltd Method of treating a carbon dioxide rich flue gas and a flue gas treatment system
US10518212B2 (en) * 2012-10-26 2019-12-31 General Electric Technology Gmbh Method of treating a carbon dioxide rich flue gas and a flue gas treatment system
US20140245270A1 (en) * 2013-02-26 2014-08-28 Red Hat, Inc. Systems and methods for providing context simulation
US20170114995A1 (en) * 2014-03-10 2017-04-27 Integrated Test & Measurement Boiler system controlling fuel to a furnace based on temperature of a structure in a superheater section
CN112131727A (zh) * 2020-09-10 2020-12-25 华北电力科学研究院有限责任公司 一种锅炉热效率评估方法、装置及设备
CN113339831A (zh) * 2021-06-02 2021-09-03 西安热工研究院有限公司 一种利用工业供汽蒸汽余热加热烟气的系统及工作方法
CN116362164A (zh) * 2023-06-02 2023-06-30 华北电力科学研究院有限责任公司 空气预热器堵塞状况确定方法及装置

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