JP2011103212A - Power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten efficiency of a power generation system and achieve simplification of its facilities. <P>SOLUTION: The power generation system is provided with a gasifying unit (10) for producing fuel gas by making oxygen react with carbon obtained by thermal decomposition of coal, a fuel cell (200) generating power by electrochemical reaction of fuel gas produced by the gasifying part and an oxidant, a pressure vessel (210) housing the fuel cell, a separating portion of a cryogenic separation unit (30) separating oxygen and nitrogen from air, an oxygen supply portion of the cryogenic separation unit (30) supplying oxygen separated in the separating portion to the gasifying unit, and a nitrogen supply portion of the cryogenic separation unit (30) supplying nitrogen separated in the separating portion into the pressure vessel as a coolant and maintaining temperature of the fuel cell generating heat by the electrochemical reaction at an operating temperature. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power generation system.

  As a power generation form for efficiently using the energy of coal, for example, IGFC (Integrated Coal Gasification Fuel Cell Combined Cycle) is known. In IGFC, coal is gasified to produce fuel gas containing hydrogen, carbon monoxide, etc., and the fuel cell is operated using this fuel gas, and the gas turbine and steam turbine are driven to generate power in a combined manner. Do.

  A power generation system that performs IGFC includes a gasification unit that partially burns coal using oxygen to generate fuel gas, a separation unit that separates oxygen from air and supplies the gas to the gasification unit, a fuel gas and an oxidant There is known a fuel cell that generates electricity by electrochemically reacting a gas, and a gas turbine and a steam turbine that generate power using fuel gas or exhaust gas from the fuel cell.

  As the fuel cell, for example, a molten carbonate fuel cell (MCFC) using molten carbonate as an electrolyte is used. The operating temperature of this MCFC is about 650 degrees, but since the temperature rises due to an electrochemical reaction during operation, refrigerant gas is supplied to maintain the operating temperature. Therefore, this power generation system further includes a refrigerant gas generation device that generates refrigerant gas and a storage tank that stores separately procured refrigerant gas in order to supply the refrigerant gas to the fuel cell (see, for example, Patent Document 1). ).

JP 2008-277118 A

In the power generation system described above, there is a problem that the equipment becomes complicated by the provision of the refrigerant gas generation device or the storage tank in order to supply the refrigerant gas to the fuel cell.
This invention is made | formed in view of the subject which concerns, and the place made into the objective is to aim at simplification of an installation while making a power generation system highly efficient.

  The power generation system of the present invention for solving the above problems includes a gasification unit that generates fuel gas by reacting oxygen with carbon obtained by pyrolysis of coal, and a fuel gas generated by the gasification unit. A fuel cell that generates electricity by electrochemical reaction with an oxidant, a pressure vessel that houses the fuel cell, a separation unit that separates oxygen and nitrogen from air, and gasification of oxygen separated by the separation unit An oxygen supply unit for supplying to the gas supply unit, a nitrogen supply unit for supplying the nitrogen separated in the separation unit into the pressure vessel as a refrigerant, and maintaining the temperature of the fuel cell that generates heat by the electrochemical reaction at an operating temperature; It is characterized by having.

  In this power generation system, nitrogen by-produced in the separation unit is supplied as a refrigerant gas for cooling the fuel cell into a pressure vessel that houses the fuel cell. For this reason, nitrogen from a separation part can be used effectively and the efficiency of a power generation system can be improved. Moreover, since it is not necessary to separately provide an apparatus for generating refrigerant gas, a storage tank for storing the procured refrigerant gas, etc., the facilities of the power generation system can be simplified. Further, since nitrogen, which is an inert gas, is supplied as a refrigerant gas into the pressure vessel, even when the fuel gas leaks from the fuel cell, the combustion gas can be prevented from causing a combustion reaction, and safety can be improved. Can be increased.

  In such a power generation system, the gasification unit reacts oxygen with the carbon to generate an intermediate fuel gas containing carbon monoxide and hydrogen, and exhaust heat generated when the intermediate fuel gas is generated. The amount of carbon monoxide contained in the intermediate fuel gas is reduced by reacting the water vapor generating portion that generates water vapor, the carbon monoxide contained in the intermediate fuel gas, and the water vapor generated by the water vapor generating portion. And a shift reactor for generating the fuel gas by decreasing and increasing the amount of hydrogen.

  In this power generation system, in the shift reactor, a shift reaction that generates carbon dioxide and hydrogen is generated from carbon monoxide contained in the intermediate fuel gas generated in the gasification furnace and water vapor generated in the water vapor generation unit. Can be made. In other words, the fuel gas can be generated by changing the composition of the intermediate fuel gas so that the carbon monoxide decreases and the hydrogen increases by the shift reactor. By supplying the fuel gas to the fuel cell and causing an electrochemical reaction, the power generation efficiency of the fuel cell can be increased, and the efficiency of the power generation system can be improved.

  In such a power generation system, the separation unit cools the air until the oxygen and the nitrogen are liquefied, and then maintains the liquid state of the oxygen and raises the temperature until the nitrogen becomes a gas. It is preferable to separate the oxygen and the nitrogen from the air.

  In this power generation system, oxygen and nitrogen are separated from air by a so-called deep-cooling separation method, so that compressed and cooled oxygen and nitrogen can be obtained. Thus, oxygen and nitrogen can be efficiently transferred to the gasification unit and the pressure vessel, respectively, and the fuel cell can be efficiently cooled. As a result, the efficiency of the power generation system can be improved.

  In such a power generation system, the fuel cell performs an electrochemical reaction between the fuel gas and the oxidant under pressure, and adjusts the flow rate of the nitrogen discharged from the pressure vessel to thereby adjust the pressure. It is preferable to further have a regulator that suppresses the difference between the pressure in the container and the pressure of the electrochemical reaction.

  In this power generation system, when the fuel cell is pressurized, the pressure in the pressure vessel can be adjusted by the regulator so as not to cause a pressure difference between the inside and the outside of the fuel cell. Accordingly, the fuel cell can be efficiently pressurized and the efficiency of the power generation system can be improved.

  In such a power generation system, oxygen and carbon dioxide in the air are preferably used as the oxidant.

  According to the present invention, the power generation system can be made highly efficient and the equipment can be simplified.

It is a schematic diagram which shows the structural example of the electric power generation system which concerns on this embodiment. It is a figure for demonstrating the electrochemical reaction of a fuel cell.

=== About power generation system ===
Hereinafter, the power generation system 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram illustrating a configuration example of a power generation system 1 according to the present embodiment. FIG. 2 is a diagram for explaining an electrochemical reaction of a molten carbonate fuel cell (MCFC) 200 provided in the power generation system 1 shown in FIG.

  The power generation system 1 includes a gasification unit 10, a first power generation unit 20 including an MCFC 200 and a pressure vessel 210, and a cryogenic separation device 30 (separation unit, oxygen supply unit, nitrogen supply unit). Further, the power generation system 1 includes a second power generation unit 40 that generates power using cathode exhaust gas discharged from the cathode 201 of the MCFC 200 described later, a third power generation unit 50 that generates power using steam, and collects carbon dioxide. And a carbon dioxide recovery unit 60.

  In the power generation system 1, composite power generation is performed by the MCFC 200, the second power generation unit 40, and the third power generation unit 50. That is, the gasification unit 10 gasifies coal to generate fuel gas, and the MCFC 200 of the first power generation unit 20 is operated using the fuel gas. Further, the second power generation unit 40 is driven using the cathode exhaust gas, and water vapor is generated by the heat from the gasification unit 10 and the MCFC 200 to drive the third power generation unit 50. Hereinafter, each configuration of the power generation system 1 will be described.

<<< Cryogenic separator >>>
The cryogenic separator 30 cools the air from which carbon dioxide and moisture have been adsorbed and removed until oxygen and nitrogen are liquefied, and then maintains the liquid state of oxygen and raises the temperature until nitrogen becomes a gas. Separate oxygen and nitrogen from the air. Therefore, in this cryogenic separation device 30, oxygen and nitrogen in a compressed and cooled state can be obtained. The cryogenic separation device 30 supplies the obtained oxygen to the gasification unit 10 and supplies the obtained nitrogen as a refrigerant of the MCFC 200 into the pressure vessel 210. At this time, since the oxygen and nitrogen are in a compressed state, the cryogenic separator 30 can efficiently transport oxygen to the gasification unit 10 and can efficiently transport nitrogen into the pressure vessel 210. Further, since the cryogenic separator 30 can supply cooled nitrogen as the refrigerant gas into the pressure vessel 210, the MCFC 200 can be efficiently cooled and maintained at the operating temperature. Therefore, the efficiency of the power generation system 1 can be improved.

<<< Gasification Department >>>
The gasification unit 10 includes a coal gasification furnace (gasification furnace) 100, a steam generation unit 110, and a shift reactor 140, and further includes a dust removing device 120 and a desulfurization device 130.

  The coal gasification furnace 100 is an intermediate fuel gas containing hydrogen, carbon monoxide, carbon dioxide and the like by pyrolyzing coal into carbon and reacting the obtained carbon with oxygen supplied from the cryogenic separator 30. Is generated.

  The steam generation unit 110 generates steam by using the exhaust heat of the intermediate fuel gas discharged from the coal gasification furnace 100, and includes a gas cooler 101 and a condenser 102. The gas cooler 101 cools the intermediate fuel gas and generates water vapor by exchanging heat between the water supplied from the condenser 102 and the intermediate fuel gas. A part of the steam generated by the gas cooler 101 is supplied to the shift reactor 140 and the rest is supplied to the third power generation unit 50. The condenser 102 collects the water vapor used in the third power generation unit 50, changes it into liquid water, and supplies it to the gas cooler 101 again. That is, in the water vapor generation unit 110, water is circulated through the gas cooler 101 and the condenser 102 while changing the water into a liquid and a gas.

  The dust removing device 120 includes, for example, a porous filter, and removes solid impurities contained in the intermediate fuel gas by passing the intermediate fuel gas discharged from the gas cooler 101 through the porous filter. For example, the desulfurization device 130 makes the intermediate fuel gas discharged from the dust removal device 120 come into contact with a sulfur absorbent such as lime water or calcium carbonate to remove sulfur components contained in the intermediate fuel gas.

The shift reactor 140 shifts the carbon monoxide contained in the intermediate fuel gas discharged from the desulfurization device 130 and the water vapor supplied from the gas cooler 101 as shown in the following equation, so that carbon dioxide and Generate hydrogen.
CO + H ₂ O → CO ₂ + H ₂

  In the shift reactor 140, the fuel gas is generated by changing the composition of the intermediate fuel gas so that carbon monoxide decreases and hydrogen increases. Note that the fuel gas discharged from the shift reactor 140 is, for example, approximately the same temperature as the operating temperature of the MCFC 200 of about 650 degrees (hereinafter simply referred to as the operating temperature). Then, it is supplied to the MCFC 200 of the first power generation unit 20.

<<< First power generation unit >>>
The first power generation unit 20 includes an MCFC 200, a pressure vessel 210, a regulator 220, a combustor 230, a compressor 240, a circulation blower 250, and a heat exchanger 260.

  The compressor 240 conveys air to the MCFC 200. The MCFC 200 reaches an operating temperature when, for example, fuel gas is supplied from the shift reactor 140, and at this operating temperature, the fuel gas and air supplied from the compressor 240 are electrochemically reacted to generate power.

  In this MCFC 200, pressurized fuel gas and air are supplied and pressurized operation is performed in order to efficiently electrochemically react fuel gas and air to increase power generation efficiency.

  For example, as shown in FIG. 2, the MCFC 200 includes a cathode 201 made of a porous nickel oxide plate, an anode 202 made of a porous nickel plate, and an electrolyte 203 made of a carbonate of a mixture of lithium carbonate and sodium carbonate. have. The cathode 201 and the anode 202 are connected by an external circuit 204 via a load 205 that consumes power obtained by the MCFC 200.

At the cathode 201, oxygen (O ₂ , oxidant) and carbon dioxide (CO ₂ , oxidant) contained in the air supplied from the compressor 240 react with electrons (2 e ⁻ ) supplied from the external circuit 204. Thus, carbonate ions (CO ₃ ²⁻ ) are generated. Further, from the cathode 201, water containing the later-described combustion exhaust gas, air containing unreacted carbon dioxide, oxygen and the like is discharged as the cathode exhaust gas. The cathode exhaust gas has an operating temperature, for example. A part of the cathode exhaust gas is supplied to the combustor 230. A part of the remaining cathode exhaust gas is returned to the cathode 201 by the circulation blower 250 and reused for the electrochemical reaction of the MCFC 200. In this way, by returning a part of the cathode exhaust gas to the cathode 201, the temperature of the air supplied to the cathode 201 can be increased to near the operating temperature, and the efficiency of the power generation system 1 can be increased. The remaining cathode exhaust gas is supplied to the second power generation unit 40.

  The electrolyte 203 is in a molten state at the operating temperature, and moves carbonate ions generated at the cathode 201 to the anode 202.

In the anode 202, hydrogen (H ₂ ) in the fuel gas supplied from the shift reactor 140 reacts with carbonate ions that have moved from the cathode 201 via the electrolyte 203, so that carbon dioxide (CO ₂ ) and Water vapor (H ₂ O) is generated, and electrons (2e ⁻ ) are emitted at the same time. The emitted electrons move to the cathode 201 through the external circuit 204, and electricity is generated by repeating this. Also, anode exhaust gas mainly containing carbon dioxide and water vapor and unreacted fuel gas, for example, having reached the operating temperature, is discharged from the anode 202. A part of the anode exhaust gas is supplied to the combustor 230, and the remaining anode exhaust gas is supplied to the third power generation unit 50 via the heat exchanger 260.

  The combustor 230 causes the oxygen in the cathode exhaust gas and the fuel gas in the anode exhaust gas to undergo a combustion reaction, and discharges the combustion exhaust gas mainly containing carbon dioxide and water vapor. The combustion exhaust gas is supplied to the cathode 201 by the circulation blower 250. This can increase the power generation efficiency of the MCFC 200 by increasing the concentration of carbon dioxide supplied to the cathode 201.

  As described above, the circulation blower 250 circulates a part of the cathode exhaust gas and the combustion exhaust gas and supplies it to the cathode 201.

  The pressure vessel 210 houses the MCFC 200 and the combustor 230. Further, nitrogen having a temperature lower than the operating temperature is supplied from the cryogenic separator 30 as a refrigerant gas inside the pressure vessel 210. With this refrigerant gas, the MCFC 200 suppresses the temperature rise accompanying the heat generation of the electrochemical reaction and maintains the operating temperature. Therefore, nitrogen produced as a by-product when oxygen is separated from air by the cryogenic separator 30 can be effectively used as the refrigerant gas of the MCFC 200, and the power generation efficiency of the power generation system 1 can be improved.

  Moreover, since the nitrogen from the cryogenic separation device 30 is supplied into the pressure vessel 210, the power generation system 1 includes a device for generating refrigerant gas, a storage tank for storing the procured refrigerant gas, and the like. There is no need. As a result, facilities can be simplified.

  Incidentally, the nitrogen supplied into the pressure vessel 210 becomes, for example, about 300 to 400 degrees by cooling the MCFC 200, and is supplied to the heat exchanger 603 of the carbon dioxide recovery unit 60 described later via the regulator 220. Is done.

  The regulator 220 is composed of a flow rate regulating valve, for example, and regulates the flow rate of nitrogen discharged from the pressure vessel 210 so that the pressure in the pressure vessel 210 is approximately equal to the pressure of the fuel gas and air supplied to the MCFC 200 or The pressure is adjusted to be higher than this pressure. This can prevent fuel gas and the like from leaking from the inside of the MCFC 200 to the outside, and the MCFC 200 can be efficiently pressurized. As a result, the power generation efficiency of the MCFC 200 can be increased and the efficiency of the power generation system 1 can be improved.

The heat exchanger 260, for example, heat-exchanges the anode exhaust gas at the operating temperature and the CO ₂ separation gas discharged from the absorption tower 601 of the carbon dioxide recovery unit 60 described later, cools the anode exhaust gas, and also cools the CO ₂ separation gas. Heat. The anode exhaust gas discharged from the heat exchanger 260 is supplied to the third power generation unit 50, and the CO ₂ separation gas is supplied to the anode 202.

<<< Second power generation section >>>
The second power generation unit 40 generates electricity using cathode exhaust gas, and includes a gas turbine 401 and a generator 402 connected to the same rotating shaft. The gas turbine 401 rotates the rotating shaft when the cathode exhaust gas is supplied. The generator 402 generates power when the gas turbine 401 rotates the rotation shaft. The compressor 240 is also connected to the same rotating shaft as the gas turbine 401 and the generator 402 and is driven in conjunction with the rotation of the gas turbine 401.

<<< Third power generation section >>>
As described above, the third power generation unit 50 generates power using water vapor. That is, water vapor generated using the anode exhaust gas discharged from the heat exchanger 260 of the first power generation unit 20 and the cathode exhaust gas discharged from the gas turbine 401 of the second power generation unit 40, and the gas of the gasification unit 10 Electric power is generated using the water vapor discharged from the cooler 101.

  The third power generation unit 50 includes exhaust heat recovery boilers 501 and 502, a steam / water separator 503, a circulation pump 504, a generator 505, steam turbines 506 and 507, and a condenser 508. .

  The exhaust heat recovery boiler 501 performs heat exchange between the anode exhaust gas discharged from the heat exchanger 260 and the water supplied by the circulation pump 504, thereby cooling the anode exhaust gas to, for example, about 40 degrees (absorption temperature). Generates water vapor. Note that the steam generated by the exhaust heat recovery boiler 501 is supplied to the steam turbine 507. Further, the anode exhaust gas, for example, having an absorption temperature in the exhaust heat recovery boiler 501 is supplied to the absorption tower 601 of the carbon dioxide recovery unit 60.

  The exhaust heat recovery boiler 502 heat-exchanges the cathode exhaust gas discharged from the gas turbine 401 and the water supplied by the circulation pump 504, thereby cooling the cathode exhaust gas and generating water vapor. The steam generated by the exhaust heat recovery boiler 502 is supplied to the steam turbine 507 together with the steam generated by the exhaust heat recovery boiler 501. Moreover, the cathode exhaust gas cooled by the exhaust heat recovery boiler 502 is supplied to the steam separator 503.

  The steam separator 503 separates water liquefied by being cooled by the exhaust heat recovery boiler 502 from the cathode exhaust gas. The cathode exhaust gas from which water has been separated by the steam separator 503 is exhausted. Further, the water taken out by the steam separator 503 is supplied to the exhaust heat recovery boilers 501 and 502 by the circulation pump 504.

  The steam turbine 507 is connected to the same rotation shaft as the steam turbine 506 and the generator 505, and rotates the rotation shaft by steam supplied from the exhaust heat recovery boilers 501 and 502. Note that the steam discharged from the steam turbine 507 is supplied to the condenser 508.

  The steam turbine 506 rotates the rotating shaft with water vapor supplied from the gas cooler 101 of the gasification unit 10. The steam discharged from the steam turbine 506 is supplied to the condenser 102 of the gasification unit 10. The generator 505 generates power by causing the steam turbines 506 and 507 to rotate the rotation shaft.

  The condenser 508 changes the water vapor supplied from the steam turbine 507 into liquid water. The water discharged from the condenser 508 is supplied to the exhaust heat recovery boilers 501 and 502 together with the water discharged from the steam separator 503 by the circulation pump 504.

<<< CO2 recovery department >>>
The carbon dioxide recovery unit 60 recovers carbon dioxide from the anode exhaust gas discharged from the exhaust heat recovery boiler 501 of the third power generation unit 50 using an absorbing liquid such as an alkanolamine aqueous solution. The absorption liquid absorbs carbon dioxide because carbon dioxide is bonded to amino groups at an absorption temperature of about 40 degrees. Moreover, since the carbon dioxide which couple | bonded with the amino group is desorbed at the regeneration temperature of about 120 ° C., the absorbing solution releases carbon dioxide.

  The carbon dioxide recovery unit 60 includes an absorption tower 601, a regeneration tower 602, heat exchangers 603 and 604, and a separator 605. In the carbon dioxide recovery unit 60, the absorption liquid absorbs carbon dioxide in the absorption tower 601, is heated to a regeneration temperature or higher in the heat exchangers 603 and 604, and releases carbon dioxide in the regeneration tower 602. Then, it is cooled again by the heat exchanger 604 and returned to the absorption tower 601.

In the absorption tower 601, the absorption liquid is brought into contact with, for example, the anode exhaust gas cooled to the absorption temperature by the exhaust heat recovery boiler 501, and the carbon dioxide in the anode exhaust gas is absorbed into the absorption liquid as shown in the following equation. In addition, R shown in the formula is an alkyl group.
R—NH ₂ + H ₂ O + CO ₂ → R—NH ₃ HCO ₃

As a result of the carbon dioxide being separated from the anode exhaust gas by the absorption tower 601, a CO ₂ separation gas mainly containing hydrogen is generated. The CO ₂ separation gas is heated by the heat exchanger 260 of the first power generation unit 20 and then supplied to the anode 202 of the MCFC 200 to be reused for the electrochemical reaction. Thereby, the efficiency of the power generation system 1 can be improved.

  The heat exchanger 604 exchanges heat between the absorption liquid at the absorption temperature discharged from the absorption tower 601 and the absorption liquid at the regeneration temperature discharged from the regeneration tower 602. The heat exchanger 604 heats the absorption liquid discharged from the absorption tower 601 and supplies it to the regeneration tower 602, cools the absorption liquid discharged from the regeneration tower 602, and supplies it to the absorption tower 601.

In the regeneration tower 602, the absorption liquid heated by the heat exchanger 604 to be higher than the absorption temperature and further maintained by the heat exchanger 603 to be higher than the regeneration temperature is stored. Then, in the regeneration tower 602, carbon dioxide is released from the absorbing solution as shown in the following equation. In addition, R shown in the formula is an alkyl group.
R—NH ₃ HCO ₃ → R—NH ₂ + H ₂ O + CO ₂

  In the regeneration tower 602, carbon dioxide released from the absorbing solution is supplied to the separator 605 together with a gas component such as water vapor.

  The heat exchanger 603 exchanges heat between the absorption liquid stored in the regeneration tower 602 and the refrigerant gas of about 300 to 400 degrees supplied from the regulator 220 of the first power generation unit 20, and stores in the regeneration tower 602. Maintain the absorbed liquid above the regeneration temperature. The cooled refrigerant gas is exhausted by the heat exchanger 603.

  The separator 605 cools the carbon dioxide and water vapor supplied from the regeneration tower 602, converts the water vapor and the like into liquid, and separates carbon dioxide from water and the like by gas-liquid separation. The carbon dioxide separated by the separator 605 is collected in a tank (not shown), for example. Further, the water or the like separated by the separator 605 is returned to the regeneration tower 602.

  As described above, in the power generation system 1 according to the present embodiment, the nitrogen produced as a by-product when the oxygen supplied to the coal gasification furnace 100 is separated from the air by the cryogenic separator 30 cools the MCFC 200. The refrigerant gas is supplied into the pressure vessel 210. For this reason, nitrogen produced as a by-product in the cryogenic separator 30 can be used effectively, and the efficiency of the power generation system 1 can be improved.

  In addition, since the cryogenic separator 30 can obtain compressed and cooled oxygen and nitrogen, oxygen can be efficiently conveyed to the coal gasifier 100 and nitrogen can be efficiently conveyed to the pressure vessel 210. be able to. Further, the MCFC 200 can be efficiently cooled by the nitrogen supplied to the pressure vessel 210.

  Furthermore, since nitrogen can be supplied as refrigerant gas from the cryogenic separator 30 into the pressure vessel 210, an apparatus for generating refrigerant gas, a storage tank for storing separately procured refrigerant gas, etc. The equipment of the power generation system 1 can be simplified because it is not necessary to provide it.

  Further, since nitrogen, which is an inert gas, is supplied into the pressure vessel 210 as a refrigerant gas, even if the fuel gas leaks from the MCFC 200, the fuel gas and the refrigerant gas can be prevented from causing a combustion reaction. , Can increase safety.

  Further, in the power generation system 1, the shift reactor 140 generates fuel gas by changing the composition of the intermediate fuel gas so that carbon monoxide is reduced and hydrogen is increased. And since this fuel gas is supplied to MCFC200 and an electrochemical reaction is carried out, the power generation efficiency of MCFC200 can be improved. Therefore, the efficiency of the power generation system 1 can be improved.

  Further, in the power generation system 1, the pressure in the pressure vessel 210 can be adjusted by the regulator 220 so as not to cause a pressure difference between the inside and the outside of the MCFC 200, and the MCFC 200 can be pressurized. Therefore, leakage of fuel gas or the like from the MCFC 200 can be suppressed, and the MCFC 200 can be efficiently pressurized. As a result, the power generation efficiency can be improved, and the efficiency of the power generation system 1 can be improved.

=== Other Embodiments ===
The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention is changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  For example, in the power generation system 1 described above, oxygen and nitrogen are separated from air by the cryogenic separator 30. However, the present invention is not particularly limited to this. For example, air may be separated into oxygen and nitrogen by a membrane separation method using a difference in permeation speed for each gas component in the polymer membrane.

DESCRIPTION OF SYMBOLS 1 ... Electric power generation system 10 ... Gasification part 20 ... 1st electric power generation part 30 ... Cryogenic separator 40 ... 2nd electric power generation part 50 ... 3rd electric power generation part 60 ... Carbon dioxide collection part 100 ... Coal gasification furnace 101 ... Gas cooler DESCRIPTION OF SYMBOLS 102,508 ... Condenser 110 ... Water vapor generating part 120 ... Dedusting device 130 ... Desulfurization device 140 ... Shift reactor 200 ... MCFC 201 ... Cathode 202 ... Anode 203 ... Electrolyte 204 ... External circuit 205 ... Load 210 ... Pressure vessel 220 ... adjuster 230 ... combustor 240 ... compressor 250 ... circulation blower 260, 603, 604 ... heat exchanger 401 ... gas turbine 402, 505 ... generator 501, 502 ... waste heat recovery boiler 503 ... steam separator 504 ... circulation Pumps 506, 507 ... Steam turbine 601 ... Absorption tower 602 ... Regeneration tower 605 ... Separator

Claims (5)

A gasification section for generating fuel gas by reacting oxygen with carbon obtained by pyrolysis of coal;
A fuel cell that generates electricity by electrochemical reaction between the fuel gas generated by the gasification unit and an oxidant;
A pressure vessel containing the fuel cell;
A separation unit for separating oxygen and nitrogen from air;
An oxygen supply unit for supplying oxygen separated in the separation unit to the gasification unit;
A nitrogen supply unit that supplies nitrogen separated in the separation unit as a refrigerant into the pressure vessel, and maintains a temperature of the fuel cell that generates heat by the electrochemical reaction at an operating temperature;
A power generation system comprising: The gasifier is
A gasification furnace for generating an intermediate fuel gas containing carbon monoxide and hydrogen by reacting oxygen with the carbon;
A water vapor generating section that generates water vapor by exhaust heat during the production of the intermediate fuel gas;
By reacting carbon monoxide contained in the intermediate fuel gas with water vapor generated by the water vapor generating unit, the amount of carbon monoxide contained in the intermediate fuel gas is decreased and the amount of hydrogen is increased. A shift reactor for generating the fuel gas;
The power generation system according to claim 1, comprising: The separation unit cools the air until the oxygen and the nitrogen are liquefied, and then maintains the liquid state of the oxygen and raises the temperature until the nitrogen becomes a gas. The power generation system according to claim 1 or 2, wherein the nitrogen and the nitrogen are separated. The fuel cell performs an electrochemical reaction between the fuel gas and the oxidant under pressure,
The apparatus further comprises a regulator that controls a difference between a pressure in the pressure vessel and a pressure of the electrochemical reaction by adjusting a flow rate of the nitrogen discharged from the pressure vessel. 4. The power generation system according to any one of 3.   The power generation system according to any one of claims 1 to 4, wherein the oxidizing agent is oxygen and carbon dioxide in the air.

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