JP5004156B2 - Power generation equipment - Google Patents

Description

  The present invention relates to a power generation facility including a molten carbonate fuel cell that obtains electric power by an electrochemical reaction between hydrogen and oxygen.

A molten carbonate fuel cell (MCFC) that obtains electric power through an electrochemical reaction between hydrogen and oxygen includes, for example, a nickel porous fuel electrode (anode) and a nickel oxide porous air electrode (cathode). The electrolyte (carbonate) is sandwiched between the two. Then, hydrogen (H ₂ ) obtained from a fuel such as natural gas is supplied to the anode, and air (O ₂ ) and carbon dioxide (CO ₂ ) are supplied to the cathode, so that the electricity of H ₂ and O ₂ can be obtained. Electricity is generated by chemical reaction. MCFC has high efficiency because it operates at a high temperature, and has features such as little influence on the environment because CO ₂ can be recovered and separated. For this reason, in recent years, it has attracted attention as a power generation system following hydropower, thermal power, and nuclear power.

  In addition, since MCFC operates at a high temperature, a power generation facility (combined power generation facility) in which the exhaust gas is supplied to the combustor of the gas turbine and the MCFC and the gas turbine are combined has been proposed ( For example, see Patent Document 1). By using a combined power generation facility that combines an MCFC and a gas turbine, it is possible to generate power with the MCFC and the gas turbine.

  In MCFC that obtains electric power by electrochemical reaction between hydrogen and oxygen, in order to obtain hydrogen as fuel, fuel gas such as natural gas is sent to the reforming means, and it is about 2 to 3 times the fuel gas to the reforming means. The fuel gas is reformed and hydrogen gas is obtained. For small power generation facilities, there are restrictions on the operating temperature of the components, but MCFC has no tolerance for the amount of reforming of fuel, and when operating in a wide load range or partial load operation at startup However, at the expense of efficiency, it is necessary to consider the operation restriction temperature.

JP-A-11-135139

  The present invention has been made in view of the above situation, and provides a power generation facility capable of appropriately maintaining the temperature of a fuel cell in a wide load range and improving efficiency and performance in a wide range of operation. With the goal.

The present invention provides a molten carbonate fuel cell in which an anode gas containing hydrogen is supplied to the anode electrode and a cathode gas containing oxygen is supplied to the cathode electrode, and electricity is generated by an electrochemical reaction between the anode gas and the cathode gas; Internal reforming means provided on the anode electrode side, external reforming means in which the exhaust of the anode electrode serves as a heat source for reforming, a fuel supply system for supplying fuel to the anode electrode, a branch from the fuel supply system, and external modification includes a reformed reformed fuel reformed fuel supply system for supplying to the anode electrode in the external reformer is supplied to the fuel quality device, and adjusting means for adjusting the amount of fuel branching from the fuel supply system Yes.

For this reason, a part of the fuel is supplied to the anode electrode via the external reformer, and a part of the fuel is directly supplied to the anode electrode by bypassing the external reformer. The temperature adjustment of the molten carbonate fuel cell is adjusted by the balance between the amount of fuel gas supplied to the external reformer and the amount supplied directly to the anode electrode, bypassing the external reformer. That is, the fuel (methane fuel) passing through the external reformer is reformed in advance to hydrogen and carbon monoxide, and the methane concentration is lowered. The reformed gas and methane bypassing the external reformer are mixed and supplied to the anode electrode, whereby the methane gas concentration in the fuel supplied from the outside of the molten carbonate fuel cell is adjusted, and the molten carbonate fuel The reforming amount inside the battery, that is, the endothermic amount in the molten carbonate fuel cell is arbitrarily set to maintain the temperature appropriately.

  The combined use of such internal reforming and external reforming is applied to a power generation facility of a 300 MW class oxygen-utilized molten carbonate fuel cell. By adjusting the flow rate balance between external reforming and internal reforming, it is possible to realize a power generation facility. As a result, the temperature of the molten carbonate fuel cell can be adjusted only by adjusting the balance of the flow path of the fuel gas, and the temperature of the molten carbonate fuel cell can be controlled under a wide range of operating conditions. This can be applied to other than the molten carbonate fuel cell using oxygen.

Further, pressurizing means for pressurizing the cathode gas supplied to the cathode electrode, a cathode exhaust of the cathode electrode and a combustor for combusting the anode exhaust heat recovered by the external reformer, and a combustion gas from the combustor are expanded. And a turbine for obtaining power .

For this reason, it becomes power generation equipment which pressurizes cathode gas and can collect power with a turbine.

And a fuel preheating means for preheating the fuel in the fuel supply system using the exhaust gas of the turbine as a heat source, and a cathode preheating means for preheating the cathode gas pressurized by the pressurizing means using the exhaust gas of the turbine as a heat source. ing.

For this reason, fuel preheating and cathode gas preheating can be performed by the energy in the system.

In order to achieve the above object, a power generation facility according to a first aspect of the present invention is configured such that an anode gas containing hydrogen is supplied to an anode electrode and a cathode gas containing oxygen is supplied to a cathode electrode. A molten carbonate fuel cell that generates electricity by an electrochemical reaction, an internal reforming means provided on the anode side, an external reforming means in which the exhaust of the anode pole is used as a heat source for reforming, and steam for reforming A fuel supply system that supplies steam and fuel to the anode electrode, and supplies the steam and fuel to the external reformer branched from the fuel supply system and the reformed fuel reformed by the external reformer to the anode electrode A reformed fuel supply system to be supplied, an adjusting means for adjusting the amount of steam / fuel branched from the fuel supply system, a combustor for combusting the cathode exhaust and the anode exhaust recovered by the external reformer, and a combustor Burning Provided with a fuel preheating means for preheating the steam and fuel of the fuel supply system by recovering heat from the fuel and a cathode gas preheating means for preheating the cathode gas by further recovering the combustion gas recovered by the fuel preheating means. It is characterized by.

In the present invention according to claim 1, a part of the steam / fuel is supplied to the anode electrode via the external reformer, and a part thereof is directly supplied to the anode electrode, bypassing the external reformer. The temperature of the molten carbonate fuel cell is adjusted by a balance between the amount of steam / fuel gas supplied to the external reformer and the amount supplied directly to the anode electrode, bypassing the external reformer. That is, the steam / fuel passing through the external reformer is reformed into hydrogen and carbon monoxide, and the methane concentration is lowered. By mixing this reformed gas and steam / fuel bypassing the external reformer and supplying them to the anode electrode, the methane gas concentration in the steam / fuel supplied from the outside of the molten carbonate fuel cell is adjusted and melted. The reforming amount inside the carbonate fuel cell, that is, the endothermic amount in the molten carbonate fuel cell is arbitrarily set to maintain the temperature appropriately.

The combined use of such internal reforming and external reforming is applied to a power generation facility of a 300 MW class oxygen-utilized molten carbonate fuel cell. By adjusting the flow rate balance between external reforming and internal reforming, it is possible to realize a power generation facility. As a result, the temperature of the molten carbonate fuel cell can be adjusted only by adjusting the balance of the flow path of the steam / fuel gas, and the temperature of the molten carbonate fuel cell can be controlled under a wide range of operating conditions. . This can be applied to other than the molten carbonate fuel cell using oxygen.
Then, steam / fuel preheating and cathode gas preheating can be performed by the energy in the system.

The power generating plant of the present invention according to claim 2 is the power generating plant according to claim 1, you characterized by including a temperature control unit to suppress the temperature of the combustion gases from the combustor.

In this invention which concerns on Claim 2, the temperature of the combustion gas from a combustor can be adjusted appropriately.

A power generation facility according to a third aspect of the present invention is the power generation facility according to the second aspect, wherein the temperature adjustment means is a CO ₂ gas that is supplied from the combustion gas recovered by the cathode preheating means to the CO ₂ gas. it is a ₂ gas input system.

In the present invention according to claim 3, the temperature of the combustion gas from the combustor can be appropriately adjusted by the CO ₂ gas recovered in the system.

A power generation facility according to a fourth aspect of the present invention is the power generation facility according to any one of the first to third aspects, wherein pure oxygen at a predetermined pressure is supplied as a cathode gas of the molten carbonate fuel cell, the ratio of hydrogen and oxygen characterized in that the supplied molten carbonate fuel cell in a predetermined stoichiometric ratio is operated.

In the present invention according to claim 4, oxygen is supplied in an equivalent ratio to the fuel, and power generation is provided with a molten carbonate fuel cell in which stoichiometric operation is performed in which the ratio of hydrogen to oxygen becomes a predetermined stoichiometric ratio. It can be equipment.

The power generation facility according to claim 5 of the present invention is the power generation facility according to claim 4, wherein the pure oxygen at a predetermined pressure is oxygen produced by concentrating nitrogen gas by pressure swing adsorption and removing it from the air. it shall be the features a.

In this invention which concerns on Claim 5, it can be set as the power generation equipment provided with the molten carbonate fuel cell which can obtain oxygen of a pressurized state easily, and does not need to be provided with the equipment which pressurizes oxygen.

In order to achieve the above object, a power generation facility according to a sixth aspect of the present invention is configured such that an anode gas containing hydrogen is supplied to an anode electrode and a cathode gas containing oxygen is supplied to a cathode electrode. Molten carbonate fuel cell that generates electricity by electrochemical reaction, internal reforming means provided on the anode side, external reforming means that the anode exhaust is used as a heat source for reforming, and fuel supplied to the anode pole A fuel supply system, a reformed fuel supply system that branches from the fuel supply system, supplies fuel to the external reformer, and supplies reformed fuel reformed by the external reformer to the anode electrode, and fuel supply An adjusting means for adjusting the amount of fuel branched from the system, a compressor for pressurizing the cathode gas supplied to the cathode electrode, and the cathode exhaust at the cathode electrode and the anode exhaust heat recovered by the external reformer are combusted. A combustor, a turbine for obtaining power by expanding combustion gas from the combustor, fuel preheating means for preheating fuel in the fuel supply system using exhaust gas from the turbine as a heat source, and exhaust gas from the turbine as a heat source. Cathode preheating means for preheating the cathode gas pressurized by the pressure means, and steam generating means for generating the steam of the reformed fuel supply system by further recovering the heat of the exhaust gas recovered by the fuel preheating means and the cathode preheating means If, characterized in that a circulating system for supplying the compressor with CO ₂ gas to condense the heat recovery exhaust gas by the steam generating means.

In order to achieve the above object, a power generation facility according to a seventh aspect of the present invention is configured such that an anode gas containing hydrogen is supplied to an anode electrode and a cathode gas containing oxygen is supplied to a cathode electrode. A molten carbonate fuel cell that generates electricity by an electrochemical reaction, an internal reforming means provided on the anode side, an external reforming means in which the exhaust of the anode pole is used as a heat source for reforming, and steam for reforming A fuel supply system that supplies steam and fuel to the anode electrode, and supplies the steam and fuel to the external reformer branched from the fuel supply system and the reformed fuel reformed by the external reformer to the anode electrode Heat is recovered by the reformed fuel supply system to be supplied, adjusting means for adjusting the amount of steam / fuel branched from the fuel supply system, a blower for pressurizing the cathode gas supplied to the cathode electrode, the cathode exhaust and the external reformer. A combustor that burns the anode exhaust, a fuel preheating means that preheats the combustion gas from the combustor to preheat steam and fuel in the fuel supply system, and further recovers the combustion gas recovered by the fuel preheating means. The cathode gas preheating means for preheating the cathode gas, the steam generating means for recovering the exhaust gas heat recovered by the cathode preheating means, and generating the steam of the fuel supply system, and the exhaust gas heat recovered by the steam generating means the CO ₂ gas to condense the gas characterized in that a circulating system for supplying the blower.

  The power generation facility of the present invention can be a power generation facility that can appropriately maintain the temperature of the fuel cell in a wide range of loads and can improve efficiency and performance in a wide range of operation.

  In the power generation facility according to the embodiment of the present invention, natural gas is used as the fuel, and the oxygen production apparatus applies a PSA system in which nitrogen gas is concentrated by pressure swing adsorption and removed from the air to produce oxygen. Yes. The molten carbonate fuel cell (MCFC) stack employs an internal reforming stack in which a catalyst (internal reforming means) is attached to the anode flow path, and has an external reformer. In addition to the external reformer, it has a reformer bypass line so that fuel can be supplied directly to the MCFC stack. The flow rate of fuel flowing through the fuel bypass line and the fuel (steam flowing through the external reformer) The fuel gas composition supplied to the MCFC stack is adjusted by adjusting the flow rate of the mixed fuel). The gas (anode gas) whose reforming rate is adjusted is supplied to the MCFC stack, performs internal reforming reaction and power generation reaction, and adjusts the temperature inside the MCFC stack according to the reforming reaction amount.

  The first embodiment will be specifically described.

  1 is a schematic system of a power generation facility according to the first embodiment of the present invention, FIG. 2 is a temperature condition in high load / low load operation, FIG. 3 is a temperature relationship in high load / low load operation, FIG. FIG. 6 shows the relationship of various states to the output of the power generation facility, and FIG. 7 shows the performance of the power generation facility.

The configuration of the power generation facility will be described with reference to FIG.
As shown in FIG. 1, the power generation facility 1 according to the present embodiment includes a molten carbonate fuel cell (MCFC) 2, and a combustor in which an outlet gas (exhaust gas) of the MCFC 2 is introduced to perform combustion. 3 is provided. A turbine 4 (for example, a micro gas turbine) that expands and drives combustion gas from the combustor 3 is provided. The turbine 4 is provided with a generator 5 on the same axis. The generator 5 is actuated by driving the turbine 4 to generate electricity. Reference numeral 6 in the figure is a mixer provided on the upstream side of the combustor 3 to prevent backfire.

The MCFC 2 is configured, for example, by sandwiching an electrolyte (carbonate) between a fuel electrode (anode) 7 of a nickel porous body and an air electrode (cathode) 8 of a nickel oxide porous body, for example. . Then, hydrogen (H ₂ ) obtained from the fuel f such as natural gas is supplied to the anode 7, and air (O ₂ ) and CO ₂ are supplied to the cathode 8, so that the electrochemistry of H ₂ and O ₂ is achieved. Electricity is generated by the reaction.

  Downstream of the turbine 4, a fuel preheater 9 and a cathode gas preheater 10 that perform heat recovery of exhaust (exhaust gas) that has finished work in the turbine 4 are provided in parallel, and the fuel preheater 9 and the cathode gas preheater 10. A steam generator 11 is provided on the downstream side. The steam generated in the steam generator 11 is mixed with the fuel f as steam for reforming.

The exhaust gas heat-recovered by the steam generator 11 is condensed by the condenser 12 and separated into water (H ₂ O) and non-condensable gas (CO ₂ ). The CO ₂ separated by the condenser 12 is compressed together with O _{2 by the} compressor 13 and sent to the cathode gas preheater 10 as a pressurized cathode gas (circulation system). A mixed gas (cathode gas) of O ₂ and CO ₂ preheated by the cathode gas preheater 10 is supplied to the cathode 8 of the MCFC ₂ . Excess CO ₂ is separately collected and the condensed H ₂ O is supplied to the steam generator 11 by the water supply pump 14.

The compressor 13 is supplied with O ₂ produced by concentrating nitrogen gas by pressure swing adsorption and removed from the air (PSA method), for example, having a composition of 95% oxygen and 5% nitrogen. .

If O ₂ supplied by the PSA method is pressurized to a predetermined pressure, it can be mixed with CO ₂ compressed on the outlet side of the compressor 13. In this case, the compressor 13 provided in the circulation system can be a CO ₂ compressor that compresses only CO ₂ . Since the compressed fluid is specified by using a compressor that compresses only CO ₂ , the compressor can be easily designed and the like. It is also possible to supply normal pressure pure O ₂ from the cryogenic equipment to the compressor 13.

  On the other hand, the anode 7 of the MCFC 2 is provided with a catalyst 15 as internal reforming means, and the anode gas is reformed by the catalyst 15 to cause an endothermic reaction. An external reformer 16 as an external reforming means is provided on the exhaust side of the anode 7 of the MCFC 2, and the exhaust from the anode 7 is sent to the mixer 6 as a reforming heat source of the external reformer 16.

  The fuel f (for example, methane) is sent to the fuel preheater 9 from a supply path 21 as a fuel supply system, preheated by the fuel preheater 9 and supplied to the anode 7 of the MCFC 2. Further, a reformed fuel supply path 17 as a reformed fuel supply system for supplying the fuel f to the external reformer 16 is branched and provided in the supply path 21 on the upstream side of the fuel preheater 9. Steam from the steam generator 11 is mixed into the reformed fuel supply path 17, and the fuel f mixed with the steam is reformed by the external reformer 16 and supplied to the anode 7 of the MCFC 2.

  The supply path 21 where the reformed fuel supply path 17 branches is provided with adjusting means 18 for adjusting the amount of fuel to be branched into the reformed fuel supply path 17. The adjusting means 18 adjusts the amount of fuel f supplied directly to the anode 7 of the MCFC 2 and the amount of fuel f mixed with the steam and reformed by the external reformer 16. By adjusting the amount of the fuel f branched by the adjusting means 18, the fuel f reformed by the catalyst 15 and undergoing endothermic reaction is adjusted.

In the power generation facility 1 described above, the exhaust gas of the MCFC 2 is completely burned by the combustor 3 to drive the turbine 4, the heat of the exhaust gas of the turbine 4 is recovered, and the condenser 12 condenses water (H ₂ O) and non-condensable gas (CO ₂ ). Among these, H ₂ O generated by the cell reaction and combustion is discharged out of the system, and CO ₂ is pressurized and circulated as a cathode gas.

Therefore, by supplying only the equivalent ratio of O ₂ to the fuel f and performing stoichiometric operation,
It becomes possible to build a closed cycle system that can collect CO ₂ generated by power generation and obtain CO ₂ at a high concentration as an oxidant for cathode gas. It can be set as the power generation equipment 1 which can be planned. Further, the anode gas and the cathode gas can be appropriately heated using the exhaust heat of the turbine 4.

  The adjusting means 18 adjusts the amount of the fuel f supplied directly to the anode 7 of the MCFC 2 and the amount of the fuel f mixed with the steam and reformed by the external reformer 16, so that the reforming rate is increased. The adjusted gas (anode gas) is supplied to the anode 7 of the MCFC 2 to perform an internal reforming reaction and a power generation reaction, and the temperature of the MCFC 2 is adjusted by the amount of the reforming reaction. The operation temperature of the MCFC 2 is maintained at a predetermined temperature by the endothermic reaction, and the operation temperature of the MCFC 2 can be controlled to a predetermined state without using power for temperature control.

  The inlet temperature of the turbine 4 (micro gas turbine) is required to be kept at about 950 ° C. or less from the viewpoint of the durability temperature of the metal. For this reason, it is necessary to design the operation so that the combustion gas temperature of the combustor 3 does not exceed the allowable value during the partial load operation. In the power generation facility 1 described above, the ratio of the heat dissipated from the power generation facility 1 to the heat generation amount of the fuel f supplied to the power generation facility 1 during partial load operation including startup is increased. The amount of heat for raising the temperature of the gas is insufficient. In order to compensate for the shortage of heat, it is necessary to reduce the utilization rate of the fuel f and to increase the amount of heat generated at the outlet of the MCFC 2. On the other hand, when the utilization factor of the fuel f decreases, the amount of unburned gas in the exhaust gas of the anode 7 increases, and the temperature at the outlet of the combustor 3 (inlet of the turbine 4) tends to increase. As a measure against temperature restrictions in the power generation facility 1, an external reformer 16 is disposed at the outlet of the anode 7 in order to simultaneously adjust the temperature of not only the MCFC 2 but also the entire facility.

  FIG. 2 shows a table of temperature conditions at high load and low load, and FIG. 3 shows a conceptual diagram of heat generation at high load and low load.

  When the load is high, the amount of heat generated inside the power generation facility 1 is large, so the amount of heat dissipated from the facility is relatively reduced. Therefore, the amount of heat for raising the temperature of the necessary gas in the power generation facility 1 is sufficient, and high-efficiency operation by increasing the fuel utilization rate is possible. On the other hand, during low load operation, the amount of heat dissipated relative to the amount of heat generated inside the power generation facility 1 increases. Therefore, in order to raise the gas required for operation, it is necessary to set the fuel utilization rate low and keep the heat quantity downstream from the MCFC 2 high. During low load operation, the amount of heat generated in the MCFC 2 decreases due to a decrease in current density, and as a result, the cooling rate of the MCFC 2 due to internal reforming decreases, and as a result, the supply rate of the fuel f to the external reformer 16 increases. The amount of heat generated by the exhaust gas from the anode 7 increases as the fuel utilization rate decreases, and the temperature of the combustor 3 increases. However, the increase in the reforming reaction amount in the external reformer 16 It acts in the direction of lowering the temperature and cancels both.

  By adopting such a configuration of the power generation facility 1, it is possible to keep the outlet temperature of the combustor 3 low in a high load to low load operation state. That is, the MCFC 2, the external reformer 16, and the turbine 4 which are the main devices of the power generation facility 1 exhibit a stable behavior regardless of the load, and a stable system operation is possible in a wide load region.

  In the power generation facility 1 of the pressurization system shown in FIG. 1, in addition to applying a configuration in which the internal reforming (catalyst 15) and the external reforming by the external reformer 16 are combined to control the temperature of the MCFC 2, the external reforming is performed. A vessel 16 is arranged at the outlet portion of the anode 7. In the case of MCFC2 using oxygen, the gas flow rate is high and the exhaust gas having a high temperature has a large amount of heat. The endothermic reaction of the catalyst 15 is supplemented by the exhaust gas of the anode 7 and the exhaust gas cooling effect by the external reformer 16 is combined, so that the combustor 3 can be used even when the fuel utilization rate is changed in a wide operating load range. It is possible to keep the outlet temperature constant.

  More specifically, the power generation characteristics of the power generation facility 1 will be discussed.

  As the turbine 4, for example, a case where a 4 atm operation type micro gas turbine is used will be described. In the case of the power generation facility 1, the power is recovered by the turbine 4, so that the amount of heat of the exhaust gas of the turbine 4 tends to decrease. Therefore, in the fuel preheater 9, only the fuel f is heated, and the reforming steam is heated only by the external reformer 16.

  FIG. 4 shows the bypass ratio of the external reformer 16 with respect to the output (kW) of the power generation facility 1, that is, the internal reforming ratio by the catalyst 15 and the outlet temperature of the combustor 3. FIG. 5 shows the operating pressure, the S / C value, the MCFC2 gas utilization rate, and the outlet methane concentration of the external reformer 16 with respect to the output (kW) of the power generation facility 1.

The bypass ratio of the external reformer 16 is obtained as a result of adjusting the internal reforming reaction so that the outlet temperature of the anode 7 (stack outlet temperature) becomes, for example, 670 ° C. In the case of rated load (for example, current density 1800 mA / m ² , system output 1100 kW), the amount of heat generated in the stack increases, so stack cooling by internal reforming is necessary, and most of the fuel f is externally reformed. Therefore, the cooling effect of the anode exhaust gas due to the reforming reaction of the external reformer 16 is hardly obtained. Further, the amount of steam supplied to the external reformer 16 is defined by the S / C value of the equipment, but the amount of fuel f supplied to the external reformer 16 decreases as the required amount of internal reforming increases. To do. For this reason, the steam ratio at the inlet of the external reformer 16 is, for example, about 98%, and the reforming reaction easily proceeds, so that almost no methane remains at the outlet of the external reformer 16. Since methane is not supplied from the external reformer 16, methane supply for internal reforming is supplied exclusively from the supply path 21 (a line that bypasses the external reformer 16). It is close to%.

  On the other hand, in the high load region, heat generation from the inside of the power generation facility 1 is increased, and the amount of heat dissipated from the facility is relatively reduced, so that a sufficient amount of heat is supplied to raise the necessary gas in the power generation facility 1. Therefore, the fuel utilization rate can be set as high as 85%, for example. As a result of combining these effects, the inlet temperature of the turbine 4 is maintained at about 910 ° C., for example.

When the load is low (for example, current density 1000 mA / m ² , system output 600 kw), the amount of heat generated in MCFC ² is small, so the bypass rate of the external reformer that represents the ratio of the fuel flow rate required for internal reforming Is as low as about 60%, for example. As the bypass rate of the external reformer 16 decreases, the ratio of the fuel f to the steam supplied to the external reformer 16 increases, and the methane ratio at the outlet of the external reformer 16 increases. The inside of the stack is cooled by the remaining methane at the outlet of the external reformer 16 and, for example, methane supplied by the bypass of the external reformer 16 of 60%. Further, since the rate of heat dissipation from the facility is relatively large when the load is low, the fuel utilization rate is a low value (for example, 78%) compared to the rated operation. Since the fuel utilization rate is low, the unburned gas component at the outlet of the MCFC 2 has increased from the rated load, but the fuel ratio of the external reformer 16 has also increased (the external reformer bypass rate has decreased) Therefore, the outlet temperature of the combustor 3 does not rise. As can be seen from FIG. 4, the outlet temperature of the combustor 3 is in the temperature range of 890 ° C. to 910 ° C., for example, when the load of the power generation facility 1 is in the range of 50% to 100%, and the load is greatly changed. Even in this case, the change in the outlet temperature of the combustor 3 is small.

FIG. 6 shows the relationship between the output (kW) of the power generation facility during the partial load operation, the MCFC2 / gas turbine (GT) output, the cell voltage, and the power transmission end efficiency. FIG. 7 shows performance analysis results and equipment performance conditions of the power generation facility 1 under rated conditions (for example, at a current density of 1800 mA / m ² ).

The power transmission end efficiency is, for example, 60% HHV under a rated current density condition of a current density of 1800 mA / m ² (for example, an output of the power generation facility 1 of 1100 kW), which is very high thermal efficiency as a 1 MW class system. Is shown. Further, for example, even in a partial load operation state with a current density of 1000 mA / m ² (for example, output 600 kW of the power generation facility 1), the power transmission end thermal efficiency is as high as 52% HHV, for example, from a load of about 50% to 100 50% transmission end efficiency can be secured in a wide load range up to a load of 50%. The cell voltage is, for example, 909 mV at the rated load, and 946 mV, for example, at the 50% load.

On the other hand, paying attention to the output of the turbine 4, for example, it is 106 kW at the rated load, whereas it is extremely reduced to, for example, 8 kW at the load of 50%. In equipment using oxygen, gas is supplied at a stoichiometric ratio between natural gas and oxygen, and the cathode gas is a noble gas, so the utilization rate of carbon dioxide gas is almost equal. Therefore, the flow rate of the turbine 4 decreases when the load decreases. Further, since the operation is performed to reduce the rotation speed of the turbine 4 in accordance with the decrease in the gas flow rate in the turbine 4, the pressure of the turbine 4, that is, the operation pressure of the MCFC 2 is reduced at the time of partial load. Due to changes in the operating conditions of these turbines 4, the gas turbine output is greatly reduced at the time of partial load.
The performance of the power generation facility 1 is, for example, as shown in FIG.

The second embodiment will be specifically described.
In the case of assuming a small-scale oxygen-based power generation facility, it is advantageous from the viewpoint of introduction cost to use a normal-pressure operation type power generation facility. In the case of a power generation facility using oxygen, since the cathode gas flow rate is small, the pressure loss of the cathode gas inside the stack is also small, so that problems such as wet seal leakage can be avoided even in an atmospheric pressure system.

  In the case of the normal pressure operation type power generation equipment, since the gas turbine is not set, the fuel preheater and the cathode preheater are exposed to high-temperature combustion gas. Therefore, in addition to the limitation of the heat resistant temperature of the heat exchanger, in order to select the specification of an inexpensive metal member, it is necessary to lower the temperature of the heat medium to the heat exchanger. For this reason, as in the power generation facility 1 of the first embodiment, the basic configuration is a facility in which an external reformer is installed at the anode outlet of the internal reforming MCFC.

  FIG. 8 is a schematic diagram of a power generation facility according to the second embodiment of the present invention, FIG. 9 is a temperature state in high load / low load operation, and FIGS. 10 to 12 are relationships of various states with respect to the output of the power generation facility. FIG. 13 shows the performance of the power generation facility.

  The configuration of the power generation facility will be described based on FIG.

  As shown in FIG. 8, the power generation facility 31 of the present embodiment is provided with a molten carbonate fuel cell (MCFC) 32, and a combustor in which an outlet gas (exhaust gas) of the MCFC 32 is introduced and combustion is performed. 33 is provided. Reference numeral 36 in the drawing is a mixer provided on the upstream side of the combustor 33 to prevent backfire.

The MCFC 32 is configured, for example, by sandwiching an electrolyte (carbonate) between a fuel electrode (anode) 37 of a nickel porous body and an air electrode (cathode) 38 of a nickel oxide porous body, for example. . Then, hydrogen (H ₂ ) obtained from the fuel f such as natural gas is supplied to the anode 37, and air (O ₂ ) and CO ₂ are supplied to the cathode 38, so that the electrochemistry of H ₂ and O ₂ is achieved. Electricity is generated by the reaction.

  Downstream of the combustor 33, a fuel preheater 39 that performs heat recovery of the combustion gas of the combustor 33 is provided, and a combustion gas recovered by the fuel preheater 39 is provided with a cathode gas preheater 40. Further, a steam generator 41 is provided on the downstream side of the cathode gas preheater 40, and exhaust gas recovered by the cathode gas preheater 40 is sent. The steam generated by the steam generator 41 is mixed with the fuel f as steam for reforming.

The exhaust gas heat recovered by the steam generator 41 is condensed by the condenser 42 and separated into water (H ₂ O) and non-condensable gas (CO ₂ ). The CO ₂ separated by the condenser 42 is pumped by the CO ₂ blower 43, mixed with O ₂ , and then sent to the cathode gas preheater 40 as a normal pressure cathode gas (circulation system). A mixed gas (cathode gas) of O ₂ and CO ₂ preheated by the cathode gas preheater 40 is supplied to the cathode 38 of the MCFC 32. Excess CO ₂ is separately collected and the condensed H ₂ O is supplied to the steam generator 41 by a water supply pump 44.

The flow after the CO ₂ blower 43 is provided extraction line 45, CO ₂ extracted by the extraction line 45 is introduced into the mixer 36 (CO ₂ gas input). When CO ₂ is introduced into the mixer 36 from the extraction line 45, the temperature of the combustion gas from the combustor 33 is adjusted. That is, the temperature of the combustion gas is adjusted to a temperature that does not affect the equipment of the fuel preheater 39 (temperature adjusting means).

By using a system in which CO ₂ is mixed as the temperature adjusting means, an existing combustor can be easily applied. As the temperature adjusting means, it is possible to adjust the temperature of the combustion gas by applying a combustor in which a heat insulating structure is eliminated or a heat dissipating member is attached instead of the system in which CO ₂ is mixed.

The downstream side of the extraction line 45 is supplied with O ₂ produced by concentrating nitrogen gas by pressure swing adsorption and removed from the air (PSA method). For example, oxygen is 95% and nitrogen is 5%. It is considered as a composition. It is also possible to supply normal pressure pure O ₂ from the cryogenic equipment to the downstream of the CO ₂ blower 43.

  On the other hand, the anode 37 of the MCFC 32 is provided with a catalyst 46 as an internal reforming means, and the anode gas is reformed by the catalyst 46 to cause an endothermic reaction. An external reformer 47 as an external reforming means is provided on the exhaust side of the anode 37 of the MCFC 32, and the exhaust of the anode 37 is sent to the mixer 36 as a reforming heat source of the external reformer 47.

  The fuel f (for example, methane) is joined to the steam line from the steam generator 41, and steam / fuel (anode gas) including steam for reforming is sent to the fuel preheater 39 from the supply path 48 as a fuel supply system. The fuel is preheated by the fuel preheater 39 and supplied to the anode 37 of the MCFC 32. In addition, a reformed fuel supply path 49 as a reformed fuel supply system for supplying anode gas to the external reformer 47 is branched and provided in the supply path 48 on the upstream side of the fuel preheater 39.

  The supply path 48 where the reformed fuel supply path 49 branches is provided with an adjusting means 50 for adjusting the amount of anode gas branched into the reformed fuel supply path 49. The adjusting means 50 adjusts the amount of anode gas supplied to the anode 37 of the MCFC 32 and the amount of anode gas reformed by the external reformer 47. By adjusting the amount of the anode gas branched by the adjusting means 50, the anode gas that is reformed by the catalyst 46 and undergoes an endothermic reaction is adjusted.

In the power generation facility 31 described above, the exhaust gas of the MCFC 32 is completely combusted by the combustor 33 to recover the heat of the combustion gas, and the condenser 42 collects condensed water (H ₂ O) and non-condensable gas (CO ₂ ). ₂ ) separated. Among these, water is supplied to the steam generator 41 generated by the battery reaction and combustion, and CO ₂ is circulated and used as the cathode gas.

For this reason, by supplying only O _{2 in an} equivalent ratio to the fuel f and performing stoichiometric operation, the entire amount of CO ₂ generated during power generation is recovered, and CO ₂ is used as a cathode gas oxidant at a high concentration. It is possible to construct a closed cycle system that can be obtained, and the power generation equipment 31 that can achieve high efficiency and high dimensions can be obtained.

  Then, the adjusting means 50 adjusts the amount of the anode gas supplied to the anode 37 of the MCFC 32 and the amount of the anode gas reformed by the external reformer 47 to adjust the reforming rate (anode). Gas) is supplied to the anode 37 of the MCFC 32 to perform an internal reforming reaction and a power generation reaction, and the temperature of the MCFC 32 is adjusted by the amount of reforming reaction. The operation temperature of the MCFC 32 is maintained at a predetermined temperature by the endothermic reaction, and the operation temperature of the MCFC 32 can be controlled to a predetermined state without using power for temperature control.

  In the case of the normal pressure system, since the gas turbine is not set, the fuel preheater 39 and the cathode gas preheater 40 are exposed to high-temperature combustion gas. Therefore, in addition to limiting the heat-resistant temperature of the device, it is necessary to lower the temperature of the device in order to select the specifications of an inexpensive metal member. Therefore, as in the first embodiment, the external reformer 47 is installed on the outlet side of the anode 37 of the internal reforming MCFC 32.

  In order to adjust the temperature of the MCFC 32 of the atmospheric system without reducing the current density of the MCFC 32, the composition of the cathode gas to the external reformer 47 and the composition of the cathode gas to the fuel preheater 39 are made equal. . That is, after mixing steam with the fuel f, the fuel is supplied to the external reformer 47 and the anode 37 (catalyst 46) of the MCFC 32. As a result, the S / C value in the external reformer 47 is lowered and the reforming rate is lowered, so that the amount of residual methane supplied from the external reformer 47 is increased. The rate drops. In the case of the normal pressure system, since there is no power recovery in the gas turbine, the fuel preheater 39 can raise the temperature of the fuel gas containing a large amount of steam.

  Furthermore, since the S / C value seen from the power generation equipment 31 is equal to the S / C value in the external reformer 47, the S / C value is added from the viewpoint of preventing carbon precipitation in the external reformer 47. Although it is necessary to raise it from the pressure system, this is also possible for the same reason, and the S / C value can be set to 2 in the power generation equipment 31.

On the other hand, in the power generation facility 31, since the reforming rate in the external reformer 47 decreases, the gas cooling capacity in the external reformer 47 at the outlet of the anode 37 becomes low, and the outlet temperature of the combustor 33 becomes lower. Reduction effect is reduced. As a mechanism for supplementing the effect of cooling the outlet of the combustor 33 by the external reformer 47, cooling in which CO ₂ is mixed from the extraction line 45 is used. In the case of an atmospheric pressure system, it is possible to supply O ₂ gas only with the PSA-type generated gas pressure, and therefore O ₂ gas pumping by a compressor is not necessary. Therefore, using a CO ₂ blower 43, it is possible to merge the O ₂ gas at the outlet side of the CO ₂ blower 43. Since the CO ₂ blower 43 can supply CO ₂ alone, a part of the outlet gas of the CO ₂ blower 43 is used as the exhaust gas of the cathode 38 for the purpose of supplementing the cooling of the combustion gas of the combustor 33. The temperature at the outlet of the combustor 33 can be lowered by merging.

In order to lower the outlet temperature of the combustor 33 by CO ₂ is also conceivable to increase the flow rate of supplied CO ₂ to the inlet of the cathode 38, in this case, the cathode gas of CO ₂ and O ₂ Since the utilization rate differs, the battery voltage of the MCFC 32 cannot be maintained high. For this reason, CO ₂ alone is merged with the outlet gas of the cathode 38.

  FIG. 9 shows a table of temperature conditions at high load and low load.

  When the load is high, the amount of heat generated inside the power generation facility 31 is large, so the amount of heat dissipated from the facility is relatively reduced. Therefore, the amount of heat for raising the temperature of the necessary gas in the power generation facility 31 is sufficient, and high-efficiency operation by increasing the fuel utilization rate is possible. On the other hand, the amount of heat dissipated relative to the amount of heat generated in the power generation facility 31 increases during low-load operation. Therefore, in order to raise the temperature of gas necessary for operation, it is necessary to set the fuel utilization rate low and keep the heat quantity downstream from the MCFC 32 high. During low load operation, the amount of heat generated in the MCFC 32 decreases due to a decrease in current density, and as a result, the cooling rate of the MCFC 32 by internal reforming decreases, and as a result, the supply rate of anode gas to the external reformer 47 increases. The amount of heat generated by the exhaust gas of the anode 37 increases as the fuel utilization rate decreases, and the temperature of the combustor 33 increases, but the increase in the reforming reaction amount in the external reformer 47 It acts in the direction of lowering the temperature and cancels both.

  By adopting such a configuration of the power generation equipment 31, it is possible to keep the outlet temperature of the combustor 33 low in a high load to low load operation state. That is, the MCFC 32 and the external reformer 47, which are the main equipment of the power generation facility 31, exhibit stable behavior regardless of the load, and a stable system operation can be performed in a wide load region.

  The power generation characteristics of the power generation facility 31 will be more specifically examined.

  FIG. 10 shows the bypass rate of the external reformer 47 with respect to the output (kW) of the power generation equipment 31, that is, the internal reforming ratio by the catalyst 46 and the outlet temperature of the combustor 33. FIG. 11 shows the S / C value with respect to the output (kW) of the power generation facility 31, the gas utilization rate of the MCFC 32, and the outlet methane concentration of the external reformer 47.

As shown in FIG. 10, for example, the bypass rate of the external reformer 47 is 74% under the rated condition of 1800 A / m ² , for example. Also, for example, since the bypass rate is about 100% under a load condition of 2150 A / m ² (for example, the output is 1200 kW), the MCFC 32 (stack) is cooled by the reforming reaction with almost the entire amount of fuel. Will be. When the load decreases, the amount of heat generated from the stack decreases, so the fuel supply ratio to the external reformer 47 increases. Therefore, an increase in the amount of reforming reaction by the external reformer 47 has an effect of lowering the exhaust gas temperature of the anode 37 and lowering the outlet temperature of the combustor 33. For this reason, the outlet temperature of the combustor 33 is lowered at the time of partial load. When the current density is, for example, 1000 A / m ² (for example, the output is 600 kW) at low load operation, the outlet temperature of the combustor 33 is reduced by about 100 ° C. compared to the maximum output (for example, the output is 1200 kW). ing.

As shown in FIG. 11, for the same reason as in the first embodiment, the fuel utilization rate is high on the high load side (for example, 85%) and low on the low load side (for example,> 70%). . In the case of the atmospheric pressure system, since the steam is supplied to both the fuel preheater 39 and the external reformer 47, the S / C value is constant in both the fuel preheater 39 and the external reformer 47, and the external For example, about 14% of methane remains at the outlet of the reformer 47. Since this methane can also be affected by the cooling of the stack, the bypass rate of the external reformer 47 is, for example, 74% in the normal pressure system when the current density is 1800 A / m ² , for example. Yes. As shown by this value, in the case of an atmospheric pressure system, the bypass rate of the external reformer 47 has a margin, so that the stack can be cooled even if the current density is increased. As a result, for example, the power generation facility 31 can be operated at a current density of up to 2150 A / m ² .

As Figure 12 shows, the thermal efficiency analysis, for example, 1800A / load than the rated point m ² high region (e.g., ~2150A / m ²⁾ was performed to demonstrated performance at that time in the drawing. The thermal efficiency when the current density is 1800 A / m ² (for example, output is 1100 kW) is 55% HHV, for example, and the thermal efficiency on the low load side (for example 1000 A / m ² ) is 47% HHV, for example. The thermal efficiency on the high load side (for example, 2150 A / m ² ) is, for example, 53% HHV.

  The performance of the power generation facility 31 is, for example, as shown in FIG.

In the power generation facility 31 that is a normal pressure system, in addition to the effect of cooling the combustor 33 by an endothermic reaction in the external reformer 16 at a low load (for example, the output is 600 kW), cooling by CO ₂ is effective. It is possible to suppress the outlet temperature of the combustor 33 to be low in a wide load region. From the above, even if the operability at low load is taken into consideration, the maximum value of the outlet temperature of the combustor 33 can be designed at, for example, about 800 ° C. and kept below the heat-resistant temperature of the heat exchanger. Is possible.

  In addition, the operable output can be, for example, 1200 kW, the cell voltage is low, and there is no other power recovery, so the characteristics of the atmospheric pressure system, that is, the amount of heat after the outlet of the combustor 33 is large. Because the system configuration that makes good use of this feature is performed, the maximum output of a high value can be realized.

In the power generation equipment of the first embodiment example and the second embodiment example described above, since the mixed gas of O ₂ and CO ₂ is supplied to the battery, the flow rate of the cathode gas is small, but the MCFC includes an internal reforming means, The methane gas concentration in the supplied fuel is adjusted externally. As a result, the reforming amount inside the MCFC, that is, the endothermic amount inside the MCFC, can be arbitrarily set, so that the MCFC temperature can be controlled under a wide range of operating conditions. The present invention can also be applied to devices other than fuel cells using oxygen.

  In the MCFC using oxygen, the outlet temperature of the combustor varies greatly depending on the operation load. In addition, unreacted fuel in MCFC is burned and heat recovery is performed by a gas turbine (in the case of a pressurized system) or a heat exchanger (in the case of an atmospheric pressure system), but these devices have restrictions on heat resistant temperature. Therefore, an external reformer for adjusting the methane concentration was arranged at the outlet of the anode so that the temperature of the entire facility could be adjusted at the same time in addition to the MCFC body.

  As a result, the cause of the increase in the combustion temperature due to the decrease in the external reforming ratio at the time of high load and the cause of the decrease in the combustion temperature due to the increase in the fuel utilization rate can be offset. On the other hand, when the load is low, the combustion temperature increase factor due to the decrease in fuel utilization to compensate for the increase in the heat dissipation rate of the equipment and the combustion temperature decrease factor due to the increase in the external reforming rate cancel each other, greatly changing the combustor outlet temperature You can drive without

As described above, for example, in the case of the pressurizing system of the first embodiment using a micro gas turbine, the outlet temperature of the combustor 3 is substantially constant in a load range of 50% to 100% (for example, 890 ° C. to 910 ° C.). And became possible. On the other hand, even in the atmospheric pressure system of the second embodiment, O ₂ and CO ₂ can be boosted separately, so that the CO ₂ blower 43 can be applied to the cathode gas supply system, and a large amount of heat can be secured in the gas preheating system, so that fuel preheating By combining with the point that the steam can also raise the temperature in the combustor, it is possible to achieve an output equivalent to that of the pressurizing system while lowering the outlet temperature of the combustor 33 (for example, 800 ° C. or less) in a wide load range. .

  From the above, it has been clarified that thermal efficiency of 50% HHV to 60% HHV can be achieved while maintaining the restrictions on the combustor temperature in a load range of 50% to 100%, for example, in both cases of pressurization and normal pressure. .

  INDUSTRIAL APPLICATION This invention can be utilized in the industrial field | area of the power generation equipment provided with the molten carbonate fuel cell which obtains electric power by the electrochemical reaction of hydrogen and oxygen.

1 is a schematic system diagram of a power generation facility according to a first embodiment of the present invention. It is a table | surface showing the temperature condition in a high load and low load operation. It is a relationship conceptual diagram showing the temperature relationship in high load and low load operation. It is a graph showing the relationship of the various states with respect to the output of a power generation facility. It is a graph showing the relationship of the various states with respect to the output of a power generation facility. It is a graph showing the relationship of the various states with respect to the output of a power generation facility. It is a table | surface showing the performance of power generation equipment. It is a schematic system diagram of the power generation equipment according to the second embodiment of the present invention. It is a table | surface showing the temperature condition in a high load and low load operation. It is a graph showing the relationship of the various states with respect to the output of a power generation facility. It is a graph showing the relationship of the various states with respect to the output of a power generation facility. It is a graph showing the relationship of the various states with respect to the output of a power generation facility. It is a table | surface showing the performance of power generation equipment.

Explanation of symbols

1,31 Power generation facilities 2,32 Molten carbonate fuel cell (MCFC)
3, 33 Combustor 4 Turbine 5 Generator 6, 36 Mixer 7, 37 Anode 8, 38 Cathode 9, 39 Fuel preheater 10, 40 Cathode gas preheater 11, 41 Steam generator 12, 42 Condenser 13 Compressor 14, 44 Water supply pump 15, 46 Catalyst 16, 47 External reformer 17 Reformed fuel supply path 18 Adjustment means 43 CO ₂ blower 45 Extraction line 48 Supply path 49 Reformed fuel supply path

Claims (7)

A molten carbonate fuel cell in which an anode gas containing hydrogen is supplied to the anode electrode and a cathode gas containing oxygen is supplied to the cathode electrode, and electricity is generated by an electrochemical reaction between the anode gas and the cathode gas;
Internal reforming means provided on the anode side,
External reforming means in which the anode exhaust is used as a reforming heat source;
A fuel supply system for supplying steam / fuel containing steam for reforming to the anode,
A reformed fuel supply system that branches from the fuel supply system and supplies steam and fuel to the external reformer and supplies reformed fuel reformed by the external reformer to the anode electrode;
Adjusting means for adjusting the amount of steam / fuel branched from the fuel supply system;
A combustor for combusting the cathode exhaust and the anode exhaust heat recovered by the external reformer;
A fuel preheating means for recovering the combustion gas from the combustor and preheating steam and fuel in the fuel supply system;
And a cathode gas preheating means for further recovering the combustion gas recovered by the fuel preheating means and preheating the cathode gas . The power generation facility according to claim 1,
A power generation facility comprising temperature adjusting means for suppressing the temperature of combustion gas from a combustor . The power generation facility according to claim 2,
Temperature adjustment means, power generation equipment, which is a CO ₂ gas input system for introducing CO ₂ gas recovered from the heat recovery and combustion gases in the cathode preheating means to the combustor. In the power generation facility according to any one of claims 1 to 3,
Power generation characterized in that pure oxygen at a predetermined pressure is supplied as a cathode gas of a molten carbonate fuel cell, and a molten carbonate fuel cell is operated with a ratio of hydrogen and oxygen supplied at a predetermined stoichiometric ratio. Facility. The power generation facility according to claim 4,
Pure oxygen at a predetermined pressure is oxygen produced by concentrating nitrogen gas by pressure swing adsorption and removing it from the air . A molten carbonate fuel cell in which an anode gas containing hydrogen is supplied to the anode electrode and a cathode gas containing oxygen is supplied to the cathode electrode, and electricity is generated by an electrochemical reaction between the anode gas and the cathode gas;
Internal reforming means provided on the anode side,
External reforming means in which the anode exhaust is used as a reforming heat source;
A fuel supply system for supplying fuel to the anode electrode;
A reformed fuel supply system that branches from the fuel supply system and supplies fuel to the external reformer and supplies reformed fuel reformed by the external reformer to the anode;
Adjusting means for adjusting the amount of fuel branched from the fuel supply system;
A compressor for pressurizing the cathode gas supplied to the cathode electrode;
A combustor for combusting the cathode exhaust of the cathode electrode and the anode exhaust recovered by the external reformer;
A turbine that obtains power by expanding the combustion gas from the combustor;
Fuel preheating means for preheating the fuel in the fuel supply system using the exhaust gas of the turbine as a heat source;
Cathode preheating means for preheating the cathode gas pressurized by the pressurizing means using the exhaust gas of the turbine as a heat source;
Steam generating means for further recovering the exhaust gas heat recovered by the fuel preheating means and the cathode preheating means to generate steam of the reformed fuel supply system;
A power generation facility comprising: a circulation system for condensing the exhaust gas heat recovered by the steam generating means and supplying CO ₂ gas to the compressor . A molten carbonate fuel cell in which an anode gas containing hydrogen is supplied to the anode electrode and a cathode gas containing oxygen is supplied to the cathode electrode, and electricity is generated by an electrochemical reaction between the anode gas and the cathode gas;
Internal reforming means provided on the anode side,
External reforming means in which the anode exhaust is used as a reforming heat source;
A fuel supply system for supplying steam / fuel containing steam for reforming to the anode,
A reformed fuel supply system that branches from the fuel supply system and supplies steam and fuel to the external reformer and supplies reformed fuel reformed by the external reformer to the anode electrode;
Adjusting means for adjusting the amount of steam / fuel branched from the fuel supply system;
A blower for pressurizing the cathode gas supplied to the cathode electrode;
A combustor for combusting the cathode exhaust and the anode exhaust heat recovered by the external reformer;
Fuel preheating means for recovering heat from combustion gas from the combustor to preheat steam and fuel in the fuel supply system;
A cathode gas preheating means for further recovering the combustion gas recovered by the fuel preheating means to preheat the cathode gas;
Steam generating means for recovering heat from the exhaust gas recovered by the cathode preheating means and generating steam for the fuel supply system;
A power generation facility comprising: a circulation system that condenses the exhaust gas heat recovered by the steam generation means and supplies CO ₂ gas to the blower .

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