JP4467929B2 - Fuel cell power generation system - Google Patents

Description

  The present invention relates to a fuel cell power generation system using a fuel cell stack that operates at a low temperature in a fuel cell power generation system that combines two types of fuel cell stacks to perform high-efficiency power generation.

  FIG. 16 is a diagram illustrating a configuration of a conventional fuel cell power generation system that performs high-efficiency power generation by combining two types of fuel cell stacks (see, for example, Non-Patent Document 1). In the conventional fuel cell power generation system shown in FIG. 16, a solid oxide fuel cell stack is used as the first fuel cell stack, and a solid polymer fuel cell stack is used as the second fuel cell stack. ing.

The fuel cell power generation system shown in FIG. 16 mainly includes a desulfurizer 2, a reformer 3, a solid oxide fuel cell stack 38, a CO shift converter 4, a CO selective oxidizer 5, a condenser 29, and a solid polymer. The fuel cell stack 9, output regulators 16 and 48, flow control valves (10, 11, 27, etc.), air supply blower 12, and piping are included. In FIG. 16, 1 is natural gas, 2 is a desulfurizer, 3 is a reformer, 4 is a CO shift converter, 5 is a CO selective oxidizer, 6 is a fuel electrode, 7 is a solid polymer electrolyte, 8 is an air electrode, 9 is a flow rate control valve for controlling the flow rate of power generation air 25 in the polymer electrolyte fuel cell stack, and 11 is a flow rate for controlling the supply amount of CO selective oxidizer air 26. Control valve, 12 is an air supply blower, 13 is an air electrode exhaust gas of the polymer electrolyte fuel cell stack, 14 is air, 15 is a fuel electrode exhaust gas of the polymer electrolyte fuel cell stack, and 16 is an output adjustment. Device, 17 is a load, 18 is a fuel cell DC output, 19 is a power transmission end AC output, 20 is a reformed gas whose carbon monoxide concentration is reduced to the ppm order, and 21 is a carbon monoxide concentration reduced to 1% or less. Modified gas, 22 Hydrogen-rich reformed gas, 23 is a mixed gas of steam and desulfurized natural gas, 24 is desulfurized natural gas, 25 is power generation air for the polymer electrolyte fuel cell stack, 26 is air for CO selective oxidizer, and 27 is natural A flow control valve for controlling the supply amount of gas 1, 28 is a reformed gas obtained by condensing unreacted water vapor, 29 is a condenser, 30 is water generated by a battery reaction, 31 is condensed water, and 32 is a modified desulfurizer for recycling. 33, a flow control valve for controlling the supply amount of reforming gas for desulfurizer recycling, 34, reforming gas for CO selective oxidizer, 35, fuel electrode, 36, solid oxide electrolyte, 37, air electrode, 38 Is the solid oxide fuel cell stack, 39 is the power generation air for the solid oxide fuel cell stack, 40 is the supply amount of the anode discharge gas 41 of the solid oxide fuel cell stack for reformer recycling control 41 is a fuel electrode exhaust gas of the solid oxide fuel cell stack for reformer recycling, 42 is a fuel electrode exhaust gas of the solid oxide fuel cell stack, and 43 is a solid oxide fuel cell. A flow rate control valve for controlling the supply amount of power generation air 39 in the cell stack, 44 is an air electrode exhaust gas of the solid oxide fuel cell stack, and 45 is a fuel electrode exhaust gas of the solid oxide fuel cell stack for discharge. , 46 is a flow control valve for controlling the supply amount of the hydrogen-rich reformed gas 22 to the CO shift converter 4, and 47 is a fuel electrode 35 of the solid oxide fuel cell stack 38 of the hydrogen-rich reformed gas 22. , 48 is an output adjusting device, 49 is a load, 50 is a fuel cell DC output, and 51 is a power transmission end AC output.
The above “hydrogen rich” means containing hydrogen at a concentration sufficient to contribute to power generation by a battery reaction.

  In FIG. 16, the polymer electrolyte fuel cell stack 9 is shown as being constituted by a single cell composed of a pair of fuel electrode 6, solid polymer electrolyte 7, and air electrode 8. The polymer electrolyte fuel cell stack 9 is composed of a plurality of single cells. Similarly, the solid oxide fuel cell stack 38 is shown as being constituted by a single cell composed of a pair of fuel electrode 35, solid oxide electrolyte 36, and air electrode 37. The solid oxide fuel cell stack 38 is composed of a plurality of single cells.

  Hereinafter, the operation of a conventional fuel cell power generation system that performs high-efficiency power generation by combining two types of fuel cell stacks will be described with reference to FIG. Fuel natural gas 1 is supplied to a desulfurizer 2. The supply amount of the natural gas 1 has a relationship between the preset battery current of the fuel cell DC output 18 and the battery current of the fuel cell DC output 50 and the opening of the flow control valve 27 (that is, the supply amount of the natural gas 1). Based on this, the opening degree of the flow control valve 37 is controlled to set a value corresponding to the battery current of the fuel cell DC output 18 and the battery current of the fuel cell DC output 50.

  In the desulfurizer 2, the reformed catalyst of the reformer 3, the fuel electrode 6 of the polymer electrolyte fuel cell stack 9, and the solid oxidation are acted on by the action of the cobalt-molybdenum-based catalyst and the zinc oxide adsorbent of the filled desulfurization catalyst. The sulfur content contained in the odorant such as mercaptan in the natural gas 1 that causes deterioration of the electrode catalyst of the fuel electrode 35 of the physical fuel cell stack 38 is adsorbed and removed by hydrodesulfurization. Specifically, sulfur and hydrogen are first reacted with a cobalt-molybdenum-based catalyst to generate hydrogen sulfide, and then hydrogen sulfide and zinc oxide are reacted to generate zinc sulfide to remove the sulfur content.

  In order to supply hydrogen necessary for the production of hydrogen sulfide, a part of the reformed gas 21 in which the concentration of hydrogen-rich carbon monoxide is reduced to 1% or less is used as a reformed gas 32 for desulfurizer recycling. Recycle to. The supply amount of the reforming gas 32 for recycling the desulfurizer is based on the preset opening degree of the flow control valve 27 (that is, the supply amount of natural gas 1) and opening degree of the flow control valve 33 (that is, the desulfurizer recycler). Based on the relationship of the supply amount of the quality gas 32), the opening degree of the flow control valve 33 is controlled to set a value commensurate with the supply amount of the natural gas 1. The generation reaction of hydrogen sulfide and sulfur sulfide is an endothermic reaction, and the reaction heat necessary for the reaction is the heat generated by the aqueous shift reaction in the CO shift converter 4 which is an exothermic reaction described later from the CO shift converter 4 to the desulfurizer 2. To cover by supplying to.

  The desulfurized natural gas 24 desulfurized in the desulfurizer 2 is an anode exhaust gas 41 of the solid oxide fuel cell stack for reformer recycling containing water vapor generated by the battery reaction in the solid oxide fuel cell stack 38. Then, the mixture is supplied to the reformer 3 as a mixed gas 23 of steam and desulfurized natural gas. The supply amount of the anode discharge gas 41 of the solid oxide fuel cell stack for reformer recycling is determined based on the preset opening degree of the flow control valve 27 (that is, the supply amount of natural gas 1) and the flow control valve 40. Natural gas by controlling the opening degree of the flow rate control valve 40 based on the relationship of the opening degree (that is, the supply amount of the fuel electrode exhaust gas 41 of the solid oxide fuel cell stack for reformer recycling). The steam carbon ratio of the mixed gas 23 of water vapor and desulfurized natural gas (the molar ratio of water vapor to anthrax in the natural gas 1) is set to a predetermined value with respect to the supply amount of 1.

In the reformer 3, a steam reforming reaction of hydrocarbons contained in the natural gas 1 is performed by the action of a reforming catalyst made of a metal oxide such as alumina carrying a metal such as nickel or ruthenium that has been charged, Rich reformed gas 22 is produced. The steam reforming reaction of methane, which is the main component of natural gas 1, is expressed by the formula (1).
(Methane steam reforming reaction)
CH ₄ + H ₂ O → CO + 3H ₂ (Chemical formula 1)
The steam reforming reaction of hydrocarbons such as the steam reforming reaction of methane shown in the formula (1) is an endothermic reaction and is necessary from the outside of the reformer 3 in order to efficiently generate hydrogen. It is necessary to supply heat of reaction and maintain the temperature of the reformer 3 at 700 to 750 ° C. Therefore, the high-temperature exhaust heat of the solid oxide fuel cell stack 38 installed near the reformer 3 described later and generating power at 800 to 1000 ° C. is used as the reaction heat necessary for the hydrocarbon steam reforming reaction. To the reformer 3.

  A part of the hydrogen-rich reformed gas 22 produced by the reformer 3 is supplied to the CO shift converter 4, and the rest is supplied to the fuel electrode 35 of the solid oxide fuel cell stack 38. The supply amount of the hydrogen-rich reformed gas 22 to the CO shift converter 4 is determined based on the preset direct current of the fuel cell DC output 18 and the opening degree of the flow control valve 46 (that is, the hydrogen rich rich gas to the CO shift converter 4). Based on the relationship of the supply amount of the reformed gas 22), the opening degree of the flow control valve 46 is controlled to set a value commensurate with the DC current of the fuel cell DC output 18. On the other hand, the supply amount of the hydrogen-rich reformed gas 22 to the fuel electrode 35 of the solid oxide fuel cell stack 38 is determined by the direct current of the fuel cell DC output 50 and the opening degree of the flow control valve 47 (that is, The fuel cell DC output is controlled by controlling the opening degree of the flow rate control valve 47 based on the relationship of the supply amount of the hydrogen-rich reformed gas 22 to the fuel electrode 35 of the solid oxide fuel cell stack 38). Set to a value commensurate with 50 direct currents.

  A part of the air 14 taken in using the air supply blower 12 is supplied to the air electrode 37 of the solid oxide fuel cell stack 38 as power generation air 39 of the solid oxide fuel cell stack. The supply amount of the power generation air 39 of the solid oxide fuel cell stack includes a preset direct current of the fuel cell DC output 50 and an opening of the flow control valve 43 (that is, power generation of the solid oxide fuel cell stack). Based on the relationship of the supply amount of the working air 39), the opening degree of the flow control valve 43 is controlled to set a value commensurate with the direct current of the fuel cell direct current output 50.

In the air electrode 37 of the solid oxide fuel cell stack 38, oxygen in the solid oxide fuel cell stack power generation air 39 is expressed by the formula (2) by the action of the metal oxide electrode catalyst. The reaction reacts with electrons and turns into oxygen ions.
(Air electrode reaction)
1 / 2O ₂ + 2e ⁻ → O ²⁻ (2)
Oxygen ions generated at the air electrode 37 move inside the solid oxide electrolyte 36 such as stabilized zirconia (YSZ) and reach the fuel electrode 35. In the fuel electrode 35, oxygen ions that have moved from the air electrode to the fuel electrode inside the solid oxide electrolyte 36 by the action of a metal-based electrode catalyst such as nickel-YSZ cermet, ruthenium-YSZ cermet, And it reacts with hydrogen and carbon monoxide in the hydrogen-rich reformed gas 22 supplied to the fuel electrode 35 by the reaction shown in the chemical formula (4), and steam or carbon dioxide and electrons are generated.
(Fuel electrode reaction)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (Chemical formula 3)
CO + O ²⁻ → CO ₂ + 2e ⁻ (Chemical formula 4)
Electrons generated at the fuel electrode 35 travel through an external circuit and reach the air electrode 37. The electrons that have reached the air electrode 37 react with oxygen by the air electrode reaction shown in the formula (2). Electric energy can be taken out as the fuel cell DC output 50 in the process of the electrons moving through the external circuit.
Summarizing the formulas (2) and (3), and the formulas (2) and (4), the battery reaction of the solid oxide fuel cell stack 38 is represented by hydrogen represented by the formula (5). It can be expressed as the reverse reaction of the electrolysis of water in which water vapor is generated from oxygen and the reaction in which carbon dioxide is generated from carbon monoxide and oxygen shown in the formula (6).
(Battery reaction)
H ₂ + 1 / 2O ₂ → H ₂ O ... (Chemical formula 5)
CO + 1 / 2O ₂ → CO ₂ ... (Chemical formula 6)
The fuel cell direct current output 50 obtained by the power generation of the solid oxide fuel cell stack 38 is subjected to voltage conversion and direct current to alternating current conversion by the output adjusting device 48 in accordance with the load 49, and then the power transmission end alternating current. The output 51 is supplied to the load 49. In FIG. 16, the output adjustment device 48 performs conversion from direct current to alternating current. However, only the voltage conversion may be performed by the output adjustment device 48, and the power transmission end DC output may be supplied to the load 49.

  The operating temperature of the solid oxide fuel cell stack 38 is generally 800 to 1000 ° C., and the operating temperature is maintained by heat generated by the battery reaction. For this reason, the exhaust heat of the solid oxide fuel cell stack 38 can be used as the reaction heat of the hydrocarbon steam reforming reaction in the reformer 3 as described above. Actually, the amount of heat generated by the battery reaction in the solid oxide fuel cell stack 38 is large, and in order to maintain the power generation temperature, a large amount of power generation air 39 of the solid oxide fuel cell stack is used. The solid oxide fuel cell stack 38 is supplied to the air electrode 37 of the cell stack 38 for cooling, and the oxygen utilization rate at the air electrode 37 is about 20%. Therefore, the supply amount of the power generation air 39 of the solid oxide fuel cell stack is changed in accordance with the supply amount of the natural gas 1 and supplied from the solid oxide fuel cell stack 38 to the reformer 3. By changing the amount of exhaust heat, it is possible to efficiently perform the steam reforming reaction of hydrocarbons in the reformer 3. That is, the preset opening degree of the flow control valve 27 (ie, the supply amount of natural gas 1) and the correction amount of the opening degree of the flow control valve 43 (ie, the power generation air 39 of the solid oxide fuel cell stack). When the supply amount of the natural gas 1 is increased based on the relationship of the correction amount of the supply amount), the power generation air 39 of the solid oxide fuel cell stack is reduced by decreasing the opening degree of the flow control valve 43. In order to increase the oxygen utilization rate at the air electrode 37 while maintaining the operating temperature of the solid oxide fuel cell stack 38 at 800 to 1000 ° C. The amount of exhaust heat supplied from the battery cell stack 38 to the reformer 3 is increased. On the other hand, when the supply amount of the natural gas 1 is decreased, a correction for increasing the supply amount of the power generation air 39 of the solid oxide fuel cell stack is performed by increasing the opening degree of the flow control valve 43, While maintaining the operating temperature of the solid oxide fuel cell stack 38 at 800 to 1000 ° C., the oxygen utilization rate at the air electrode 37 is lowered and the solid oxide fuel cell stack 38 is transferred to the reformer 3. Reduce the amount of exhaust heat supplied.

  A part of the fuel electrode exhaust gas 42 of the solid oxide fuel cell stack containing water vapor generated by the battery reaction in the fuel electrode 35 is necessary for the hydrocarbon steam reforming reaction in the reformer 3 as described above. In order to supply fresh steam, it is mixed with the desulfurized natural gas 24 as the fuel electrode exhaust gas 41 of the solid oxide fuel cell stack for reformer recycling and supplied to the reformer 3. The remainder of the fuel electrode exhaust gas 42 of the solid oxide fuel cell stack is discharged as the fuel electrode exhaust gas 45 of the discharge solid oxide fuel cell stack. By using the anode discharge gas 45 of this solid oxide fuel cell stack for discharge as a heat source for cooling with hot water, heating, and absorption refrigerators, the total thermal efficiency combining the electrical output and heat utilization of the system It is possible to improve. Moreover, the cathode exhaust gas 44 of the solid oxide fuel cell stack is also used as a heat source for hot water supply, heating, and an absorption refrigeration machine, thereby improving the overall thermal efficiency combining the electrical output and heat utilization of the system. It is possible.

Since the hydrogen-rich reformed gas 22 contains carbon monoxide which causes deterioration of the electrode catalyst of the fuel electrode 6 of the polymer electrolyte fuel cell stack 9, the solid oxide fuel cell stack 38. The hydrogen-rich reformed gas 22 that is not supplied to the fuel electrode 35 is supplied to the CO shift converter 4 filled with a shift catalyst such as a copper-zinc catalyst, and the aqueous solution shown in the chemical formula (7) by the action of the shift catalyst. By performing the shift reaction, the concentration of carbon monoxide contained in the hydrogen-rich reformed gas 22 is reduced to 1% or less.
(Water-based shift reaction)
CO + H ₂ O → CO ₂ + H ₂ (Chemical formula 7)
The aqueous shift reaction is an exothermic reaction, and the generated heat is supplied to the desulfurizer 2 and used as the reaction heat of the hydrogen sulfide and zinc sulfide generation reaction of the desulfurizer 2 which is the endothermic reaction described above.

A part of the reformed gas 21 produced by the CO shift converter 4 with the carbon monoxide concentration reduced to 1% or less is supplied to the desulfurizer 2 as the desulfurizer recycle reformed gas 32 as described above, and the rest If the carbon monoxide concentration is 100 ppm or more, it will cause deterioration of the electrode catalyst when supplied to the fuel electrode 6 of the polymer electrolyte fuel cell stack 9, so the carbon monoxide concentration is reduced to the ppm order. Therefore, as the reforming gas 34 for the CO selective oxidizer, a noble metal catalyst such as platinum or ruthenium is supplied to the CO selective oxidizer 5 filled as a CO selective oxidation catalyst. A part of the air 14 taken in by the air supply blower 12 is supplied to the CO selective oxidizer 5 as CO selective oxidizer air 26. In the CO selective oxidizer 5, carbon monoxide contained in the reformed gas 34 for CO selective oxidizer is converted into carbon dioxide by reacting with oxygen in the air 26 for CO selective oxidization, and the reformed gas for CO selective oxidizer is used. The carbon monoxide concentration of 34 is reduced to the ppm order. The CO oxidation reaction which is this exothermic reaction is shown in the formula (8).
(CO oxidation reaction)
CO + 1 / 2O ₂ → CO ₂ ... (Chemical formula 8)
The supply amount of the CO selective oxidizer air 26 is determined based on the preset opening degree of the flow control valve 46 (that is, the supply amount of the hydrogen-rich reformed gas 22 to the CO shift converter 4) and the opening degree of the flow control valve 11. Based on the relationship (that is, the supply amount of the CO selective oxidizer air 26), the opening amount of the flow control valve 11 is controlled to meet the supply amount of the hydrogen-rich reformed gas 22 to the CO shift converter 4. Set the value to Unreacted water vapor contained in the reformed gas 20 in which the carbon monoxide concentration produced by the CO selective oxidizer 5 is reduced to the order of ppm is recovered as condensed water 31 by being cooled to 100 ° C. or less by the condenser 29. To do. The reformed gas 28 obtained by condensing unreacted water vapor in the condenser 29 is supplied to the fuel electrode 6 of the polymer electrolyte fuel cell stack 9.

  On the other hand, a part of the air 14 taken in by the air supply blower 12 is supplied to the air electrode 8 of the solid polymer fuel cell stack 9 as the power generation air 25 of the polymer fuel cell stack. The supply amount of the power generation air 25 of the polymer electrolyte fuel cell stack to the air electrode 8 of the polymer electrolyte fuel cell stack 9 is determined by the battery current of the fuel cell DC output 22 and the flow control valve 10 set in advance. Of the fuel cell DC output 18 by controlling the opening of the flow rate control valve 10 based on the relationship of the opening of the fuel cell stack (that is, the supply amount of the power generation air 25 of the polymer electrolyte fuel cell stack). Set to a value appropriate for. The operating temperature of the polymer electrolyte fuel cell stack 9 is generally 60 to 80 ° C., and the operating temperature is maintained by heat generated by the battery reaction.

In the fuel electrode 6 of the polymer electrolyte fuel cell stack 9, about 80% of the hydrogen contained in the reformed gas 28 in which unreacted water vapor is condensed by the action of the platinum-based electrode catalyst is represented by the formula (9). It changes into hydrogen ions and electrons due to the fuel electrode reaction shown in.
(Fuel electrode reaction)
H ₂ → 2H ⁺ + 2e ⁻ (Chemical formula 9)
Hydrogen ions generated at the fuel electrode 6 move inside the solid polymer electrolyte 7 composed of a fluorine-based polymer having a sulfonic acid group such as Nafion and reach the air electrode 8. On the other hand, the electrons generated at the fuel electrode 6 travel through the external circuit and reach the air electrode 8. Electric energy can be taken out as the fuel cell DC output 18 in the process of the electrons moving through the external circuit.

In the air electrode 8 of the polymer electrolyte fuel cell stack 9, hydrogen ions that have moved from the fuel electrode 6 to the air electrode 8 by the action of the platinum-based electrode catalyst, and the fuel electrode 6 to the outside. Electrons that have moved the circuit to the air electrode 8 and the acid cords in the power generation air 25 of the polymer electrolyte fuel cell stack supplied to the air electrode 8 react by the air electrode reaction shown in the chemical formula (10). And water is produced.
(Air electrode reaction)
2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O (Chemical Formula 10)
When the chemical formula (9) and the chemical formula (10) are summarized, the battery reaction of the polymer electrolyte fuel cell stack 9 is the reverse reaction of the electrolysis of water that can be produced from hydrogen and oxygen shown in the formula (11). Can be expressed as
(Battery reaction)
H _{2 1/2} O ₂ → H ₂ O ... (Chemical 11)
The fuel cell direct current output 18 obtained by the power generation of the polymer electrolyte fuel cell stack 9 is subjected to voltage conversion and direct current to alternating current conversion by the output adjusting device 16 in accordance with the load 17, and then the alternating current at the power transmission end. The output 19 is supplied to the load 17. In FIG. 16, the output adjustment device 16 performs conversion from direct current to alternating current. However, the output adjustment device 16 may perform only voltage conversion and supply the power transmission end DC output to the load 17. After the power generation air 25 of the polymer electrolyte fuel cell stack consumes a part of oxygen at the air electrode 8 of the polymer electrolyte fuel cell stack 9 by the air electrode reaction shown in the chemical formula (10), It discharges as the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack. On the other hand, the reformed gas 28 in which the unreacted water vapor is condensed has consumed about 80% of hydrogen in the fuel electrode 6 of the polymer electrolyte fuel cell stack 9 by the fuel electrode reaction shown in the chemical formula (9). Then, it is discharged as the fuel electrode exhaust gas 15 of the polymer electrolyte fuel cell stack.

  A fuel power generation system that generates power by combining two types of fuel cell stacks is, for example, Japanese Patent Application No. 2002-327233 (unpublished) by the present applicant.

“Supervised by Zenichiro Takehara: Fuel cell technology and its applications, pp.141-142, Technosystem (2000)”

The problem to be solved by the present invention is that a conventional solid oxide fuel cell stack has a nickel-YSZ cermet for the fuel electrode, YSZ for the solid oxide electrolyte, and a metal oxide such as lanthanum strontium manganite for the air electrode. Used and operated at 1000 ° C. to generate electricity. However, when the operating temperature is high, there is a problem that the life is short, it takes a long time to start up, it is difficult to use an inexpensive metal material, and the apparatus cost is high. Therefore, for the low-temperature operation of the solid oxide fuel cell stack 38, a solid oxide electrolyte material having a high oxygen ion conductivity at low temperatures instead of YSZ, and a fuel electrode material and an air electrode material having high reactivity at low temperatures. Development is underway. One of the low-temperature-acting solid oxide fuel cell stacks that is currently attracting attention is a nickel-ceria-based material such as NiO— (CeO ₂ ) _0.8 (SmO _1.5 ) _0.2 in the fuel electrode 35. Performance Cermet fuel electrode, high oxygen ion conductive lanthanum gallate electrolyte such as La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _{3-α for} solid oxide electrolyte, Sm _0.5 Sr for air electrode There is a solid oxide fuel cell stack using a samarium cobaltite-based highly active air electrode such as _0.5 CoO _{3 -δ,} and is expected to operate at 600 to 800 ° C. However, when such a low-temperature operation type solid oxide fuel cell stack is applied to the fuel cell power generation system shown in FIG. 16, it can be expected to extend the life, shorten the startup time, and reduce the cost of the apparatus. When the temperature of the reformer 3 is lowered to 700 ° C. or less due to the temperature of the exhaust heat supplied from the solid oxide fuel cell stack 38 to the reformer 3, the methane concentration in the thermodynamic parallel state As a result, the concentration of methane in the hydrogen-rich reformed gas 22 also increases, so that the ratio of the fuel effectively used in the solid oxide fuel cell stack 38 and the solid polymer fuel cell stack 9 is increased. There is a problem in that the power generation efficiency of the fuel cell power generation system is reduced due to a decrease in the fuel utilization rate in terms of methane.

  An object of the present invention is to provide a fuel cell power generation system combining two types of fuel cell stacks, which can generate power with high efficiency even when using a low temperature operation fuel cell stack.

In order to solve the above-described problems, the present invention is configured as described in the claims. That is,
In the fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by the steam reforming reaction of fuel with oxygen as described in claim 1,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in hydrogen-rich reformed gas having a reduced methane concentration discharged from the first reformer into carbon dioxide and hydrogen by reacting with steam;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
The fuel cell power generation system includes a second fuel cell stack that generates power by electrochemically reacting hydrogen in the exhaust gas of the CO selective oxidizer with oxygen.

Moreover, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by the steam reforming reaction of fuel with oxygen as described in claim 2,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon dioxide and hydrogen by reacting carbon monoxide in the hydrogen-rich reformed gas with reduced methane concentration discharged from the first reformer with steam;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
The fuel cell power generation system includes a second fuel cell stack that generates power by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen.

Further, as described in claim 3, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in hydrogen-rich reformed gas having a reduced methane concentration discharged from the first reformer into carbon dioxide and hydrogen by reacting with steam;
The fuel cell power generation system includes a second fuel cell stack that generates electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen.

Further, as described in claim 4, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas into carbon dioxide and hydrogen by reacting with water vapor;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
The fuel cell power generation system includes a second fuel cell stack that generates power by electrochemically reacting hydrogen in the exhaust gas of the CO selective oxidizer with oxygen.

Further, as described in claim 5, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas into carbon dioxide and hydrogen by reacting with water vapor;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
The fuel cell power generation system includes: a second fuel cell stack that generates power by electrochemically reacting the hydrogen and oxygen separated by the hydrogen separator .

Moreover, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by the steam reforming reaction of fuel with oxygen as described in claim 6,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas into carbon dioxide and hydrogen by reacting with water vapor;
The fuel cell power generation system includes a second fuel cell stack that generates electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen.

Further, in the fuel cell power generation system for generating power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel as described in claim 7,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with water vapor;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A second fuel cell stack that generates electricity by electrochemically reacting hydrogen in the exhaust gas of the CO selective oxidizer with oxygen;
I have a,
The reformer burner are those the second der Ru fuel cell power generation system that the cathode exhaust gas and the fuel electrode exhaust gas of the fuel cell stack is combusted.

Further, in the fuel cell power generation system for generating power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel as described in claim 8,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with water vapor;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A second fuel cell stack for generating electricity by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen;
I have a,
The reformer burner are those the second der Ru fuel cell power generation system which an air electrode exhaust gas of the fuel cell stack to combust a portion of the exhaust gas of the hydrogen separator.

Further, as described in claim 9, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with water vapor;
A second fuel cell stack for generating electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen;
I have a,
The reformer burner are those the second der Ru fuel cell power generation system that the cathode exhaust gas and the fuel electrode exhaust gas of the fuel cell stack is combusted.

Further, in the fuel cell power generation system for generating power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel as described in claim 10,
At the fuel electrode, hydrogen and carbon monoxide are generated by a steam reforming reaction of the fuel, and power is generated by electrochemically reacting the hydrogen or the hydrogen and the carbon monoxide with oxygen. The generated heat is consumed as reaction heat necessary for the steam reforming reaction of the fuel at the fuel electrode, and the fuel electrode exhaust gas containing water vapor generated with the power generation is supplied to the fuel electrode. A first fuel cell stack;
A reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the reformer into carbon dioxide and hydrogen by reacting with water vapor;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A second fuel cell stack that generates electricity by electrochemically reacting hydrogen and oxygen in the exhaust gas of the CO selective oxidizer;
Have
The reformer burner are those the second der Ru fuel cell power generation system that the cathode exhaust gas and the fuel electrode exhaust gas of the fuel cell stack is combusted.

Further, as described in claim 11, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
At the fuel electrode, hydrogen and carbon monoxide are generated by a steam reforming reaction of the fuel, and power is generated by electrochemically reacting the hydrogen or the hydrogen and the carbon monoxide with oxygen. The generated heat is consumed as reaction heat necessary for the steam reforming reaction of the fuel at the fuel electrode, and the fuel electrode exhaust gas containing water vapor generated with the power generation is supplied to the fuel electrode. A first fuel cell stack;
A reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the reformer into carbon dioxide and hydrogen by reacting with water vapor;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A second fuel cell stack for generating electricity by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen;
I have a,
The reformer burner are those the second der Ru fuel cell power generation system which an air electrode exhaust gas of the fuel cell stack to combust a portion of the exhaust gas of the hydrogen separator.

Further, as described in claim 12, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
At the fuel electrode, hydrogen and carbon monoxide are generated by a steam reforming reaction of the fuel, and power is generated by electrochemically reacting the hydrogen or the hydrogen and the carbon monoxide with oxygen. The generated heat is consumed as reaction heat necessary for the steam reforming reaction of the fuel at the fuel electrode, and the fuel electrode exhaust gas containing water vapor generated with the power generation is supplied to the fuel electrode. A first fuel cell stack;
A reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas having a reduced methane concentration discharged from the reformer into carbon dioxide and hydrogen by reacting with water vapor;
A second fuel cell stack for generating electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen;
I have a,
The reformer burner are those the second der Ru fuel cell power generation system that the cathode exhaust gas and the fuel electrode exhaust gas of the fuel cell stack is combusted.

Further, as described in claim 13, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by the steam reforming reaction of fuel with oxygen,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
A CO shift converter that converts carbon monoxide in the hydrogen-rich reformed gas with a reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with steam;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
The fuel cell power generation system includes a second fuel cell stack that generates power by electrochemically reacting hydrogen in the exhaust gas of the CO selective oxidizer with oxygen.

In addition, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by the steam reforming reaction of fuel with oxygen as described in claim 14,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
A CO shift converter that converts carbon monoxide in the hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with steam;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
The fuel cell power generation system includes a second fuel cell stack that generates power by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen.

Further, as described in claim 15, in the fuel cell power generation system that generates power by electrochemically reacting hydrogen and oxygen generated by the steam reforming reaction of the fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
A CO shift converter that converts carbon monoxide in the hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with steam;
The fuel cell power generation system includes a second fuel cell stack that generates electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen.

  Further, as described in claim 16, in the fuel cell power generation system according to any one of claims 1 to 15, the first fuel cell stack is a solid oxide fuel cell stack. Thus, the second fuel cell stack is a fuel cell power generation system comprising a polymer electrolyte fuel cell stack.

  In addition, as described in claim 17, in the fuel cell power generation system according to any one of claims 1 to 15, the first fuel cell stack is a solid oxide fuel cell stack. Thus, the fuel cell power generation system in which the second fuel cell stack is a phosphoric acid fuel cell stack.

  According to the present invention, it is possible to efficiently produce a hydrogen-rich reformed gas necessary for power generation by a steam reforming reaction of fuel even when using a low-temperature-operated fuel cell stack, and two types of fuel cells There is an advantage that a highly efficient fuel cell power generation system can be realized by combining cell stacks.

[Example 1]

FIG. 1 is a diagram illustrating a configuration of a fuel cell power generation system of the present invention exemplified as a first embodiment. In FIG. 1, the same components as those in FIG. 16 described above are denoted by the same reference numerals, and description thereof is omitted. In FIG. 1, 52 is a first reformer, 53 is a second reformer, 54 is a reformer burner, 55 is a reformed gas with reduced methane concentration, and 56 is a reformer burner combustion exhaust gas. , 88 are flow rate control valves for controlling the supply amount of the reformed gas 55 with reduced methane concentration to the CO shift converter, and 89 is a solid oxide fuel cell stack 38 of the reformed gas 55 with reduced methane concentration. This is a flow rate control valve that controls the amount of fuel supplied to the fuel electrode 35.

  The fuel cell power generation system of the present invention exemplified in Example 1 will be described with reference to FIG.

  The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a first reformer 52 and a second reformer are used instead of the reformer 3 as shown in FIG. The difference is that two reformers, the reformer 53, are provided, and the second reformer 53 is provided with a reformer burner 54.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a mixed gas 23 of steam and desulfurized natural gas is supplied to the first reformer 52. In the first reformer 52, the steam reforming reaction of hydrocarbons contained in the natural gas 1 is performed by the action of the filled reforming catalyst, and the hydrogen-rich reformed gas 22 is produced. This steam reforming reaction of hydrocarbon is an endothermic reaction, and in order to efficiently generate hydrogen, high-temperature exhaust heat of the solid oxide fuel cell stack 38 installed in the vicinity of the first reformer 52 is obtained. Is supplied to the first reformer 52 as reaction heat required for the steam reforming reaction of hydrocarbons. However, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C., the temperature of the exhaust heat of the solid oxide fuel cell stack 38 is lowered, so the first reformer 52. The temperature of the gas also falls below 700 ° C., and a large amount of unreacted methane is contained in the hydrogen-rich reformed gas 22 due to thermodynamic equilibrium. Therefore, the hydrogen-rich reformed gas 22 is supplied to the second reformer 53 set to a temperature of 700 ° C. or higher, and the steam reforming of methane shown in the formula (1) is performed by the action of the filled reforming catalyst. The methane concentration in the hydrogen-rich reformed gas 22 is reduced by performing a quality reaction. A part of the reformed gas 55 with reduced methane concentration, which is the exhaust gas of the second reformer 53, is supplied to the CO shift converter 4, and the rest is the fuel electrode of the solid oxide fuel cell stack 38. 35.

  The supply amount of the reformed gas 55 in which the methane concentration is reduced to the CO shift converter 4 is the preset DC current of the fuel cell DC output 18 and the opening degree of the flow control valve 88 (that is, to the CO shift converter 4). Based on the relationship of the supply amount of the reformed gas 55 with reduced methane concentration), the opening degree of the flow control valve 88 is controlled to set a value corresponding to the direct current of the fuel cell direct current output 18. On the other hand, the supply amount of the reformed gas 55 in which the methane concentration is reduced to the fuel electrode 35 of the solid oxide fuel cell stack 38 is determined by the direct current of the fuel cell DC output 50 and the opening of the flow control valve 89. The opening degree of the flow rate control valve 89 is controlled based on the relationship of the degree (that is, the supply amount of the reformed gas 55 with reduced methane concentration to the fuel electrode 35 of the solid oxide fuel cell stack 38). Is set to a value commensurate with the direct current of the fuel cell direct current output 50.

  In order to perform the steam reforming reaction of methane, which is an endothermic reaction, by setting the second reformer 53 at 700 ° C. or higher, the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and the polymer electrolyte fuel The fuel cell stack fuel electrode exhaust gas 15 is supplied to the reformer burner 54, and the unreacted oxygen in the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and the fuel electrode of the polymer electrolyte fuel cell stack. The necessary heat is supplied from the reformer burner 54 to the second reformer 53 by burning the unreacted fuel and unreacted hydrogen in the exhaust gas 15. A reformer burner exhaust gas 56 is discharged from the reformer burner 54. In FIG. 1, in order to supply necessary heat to the second reformer 53, the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and the fuel electrode discharge of the polymer electrolyte fuel cell stack The gas 15 was supplied to the reformer burner 54 and burned, but the air electrode exhaust gas 13 of the solid polymer fuel cell stack, the air electrode exhaust gas 44 of the solid oxide fuel cell stack, and the air 14 Supply one or more of the anode discharge gas 15 of the polymer electrolyte fuel cell stack and the anode discharge gas 45 of the solid oxide fuel cell stack for discharge to the reformer burner 54 However, if oxygen, unreacted fuel, unreacted hydrogen, and unreacted carbon monoxide are combusted, the natural gas 1 as the fuel is not supplied for combustion in the reformer burner 54, and the first Water in the second reformer 53 Methane steam reforming reaction of rich reformed gas 22 to effectively take place, it is possible to reduce the methane concentration in the hydrogen-rich reformed gas 22.

In the first embodiment shown in FIG. 1, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. compared to the conventional example shown in FIG. 16, the solid oxide fuel cell stack Since the temperature of the exhaust heat supplied from 38 to the first reformer 52 is low, the temperature of the first reformer 52 is lowered to 700 ° C. or lower, and the methane concentration in the hydrogen-rich reformed gas 22 is reduced. Even if it rises, hydrogen is produced by causing the second reformer 53 to perform a steam reforming reaction of methane in the hydrogen-rich reformed gas 22, and also the hydrogen in the second reformer 53. The reaction heat required for the steam reforming reaction of methane in the rich reformed gas 22 does not use the natural gas 1 as a new fuel, and the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and the solid Fuel cell exhaust gas of polymer fuel cell stack 1 Is supplied by burning it in the reformer burner 54, so that the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the solid oxide fuel cell stack 38 and the solid polymer fuel cell stack 9 The decrease in power generation efficiency of the fuel cell power generation system can be suppressed.
[Example 2]

  FIG. 2 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the second embodiment. 2, the same components as those in FIGS. 16 and 1 described above are denoted by the same reference numerals, and description thereof is omitted. In FIG. 2, 57 is a hydrogen separator, 58 is a hydrogen separator exhaust gas, 59 is hydrogen, 60 is unreacted hydrogen, 61 is a purge valve, 62 is a purge gas, and 63 is a reforming gas for the hydrogen separator.

  The fuel cell power generation system of the present invention exemplified in Example 2 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that the first reformer 52 and the second reformer 3 instead of the reformer 3, as shown in FIG. The reformer 53 is provided with two reformers, the second reformer 53 is provided with a reformer burner 54, and a hydrogen separator 57 instead of the CO selective oxidizer 5 and the condenser 29. Is different.

Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In the present embodiment, the second reformer 53 is set to 700 ° C. or higher and the steam reforming reaction of methane, which is an endothermic reaction, is performed. The hydrogen separator exhaust gas 58 is supplied to the reformer burner 54, and unreacted oxygen in the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and unreacted fuel and unreacted in the hydrogen separator exhaust gas 58. The necessary heat is supplied from the reformer burner 54 to the second reformer 53 by burning hydrogen. A reformer burner exhaust gas 56 is discharged from the reformer burner 54. In FIG. 2, in order to supply necessary heat to the second reformer 53, the air electrode exhaust gas 13 and the hydrogen separator exhaust gas 58 of the polymer electrolyte fuel cell stack are connected to the reformer burner 54. To the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack, the air electrode exhaust gas 44 of the solid oxide fuel cell stack, and the air 14, and hydrogen. One or more of the separator exhaust gas 58 and the fuel electrode exhaust gas 45 of the solid oxide fuel cell stack for discharge are supplied to the reformer burner 54, and oxygen, unreacted fuel, unreacted hydrogen, and unreacted If the reaction carbon monoxide is combusted, the second reformer 53 does not supply the natural gas 1 as a fuel for combustion in the reforming burner 54, and the hydrogen-rich reformed gas 22 is in the second reformer 53. Efficient steam reforming reaction of methane Was performed, it is possible to reduce the methane concentration in the hydrogen-rich reformed gas 22.

  A part of the reformed gas 21 produced by the CO shift converter 4 with the carbon monoxide concentration reduced to 1% or less is a hydrogen separator 57 having a hydrogen separation membrane such as a palladium membrane as the reforming gas 63 for the hydrogen separator. And hydrogen 59 is separated. At that time, in order to perform efficient hydrogen separation, the reforming gas 63 for the hydrogen separator is pressurized as necessary. Hydrogen 59 is supplied to the fuel electrode 6 of the polymer electrolyte fuel cell stack 9 and electrochemically reacts with oxygen in the power generation air 25 of the polymer electrolyte fuel cell stack 9 to thereby produce a polymer electrolyte. Power generation of the fuel cell stack 9 is performed. All unreacted hydrogen 60 is recycled to the fuel electrode 6 and used for power generation in order to improve the power transmission end efficiency of the polymer electrolyte fuel cell stack 9. However, since the unreacted hydrogen 60 contains some impurities other than hydrogen, the purge valve 61 is opened intermittently and the purge gas 62 is released.

In the second embodiment shown in FIG. 2, the operating temperature of the solid oxide fuel cell stack 38 is 600 to 800 as compared with the conventional example shown in FIG. 16 as in the first embodiment shown in FIG. When the temperature is as low as 0 ° C., the temperature of the first reformer 52 decreases to 700 ° C. or lower because the temperature of the exhaust heat supplied from the solid oxide fuel cell stack 38 to the first reformer 52 is low. Even if the methane concentration in the hydrogen-rich reformed gas 22 increases, hydrogen is produced by causing the second reformer 53 to perform a steam reforming reaction of methane in the hydrogen-rich reformed gas 22. In addition, the reaction heat necessary for the steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 is a solid polymer without using the natural gas 1 as a new fuel. cathode exhaust gas fuel cell stack 13 and the hydrogen separator discharge Since supplied by burning a scan 58 in the reformer burner 54, the fuel of the methane conversion indicating the rate of fuel is effectively utilized in a solid oxide fuel cell stack 38 and the solid polymer fuel cell stack 9 A decrease in the utilization rate can be suppressed, and a decrease in power generation efficiency of the fuel cell power generation system can be suppressed.
[Example 3]

  FIG. 3 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the third embodiment. In FIG. 3, the same parts as those in FIGS. 16, 1, and 2 described above are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 3, 64 is a fuel electrode, 65 is a phosphoric acid electrolyte, 66 is an air electrode, 67 is a phosphoric acid fuel cell stack, 68 is a reformed gas for a phosphoric acid fuel cell stack, and 69 is a phosphoric acid fuel. Battery cell stack air electrode exhaust gas, 70 is phosphoric acid fuel cell stack fuel electrode exhaust gas, 85 is phosphoric acid fuel cell stack power generation air, 86 is phosphoric acid fuel cell stack power generation It is a flow rate control valve that controls the supply amount of air 85.

  The fuel cell power generation system of the present invention illustrated in Example 3 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a first reformer 52 and a second reformer are used instead of the reformer 3 as shown in FIG. The reformer 53 is provided with two reformers, and the second reformer 53 is provided with a reformer burner 54. The CO selective oxidizer 5 and the condenser 29 are unnecessary, the fuel electrode 6, Instead of the polymer electrolyte fuel cell stack 9 composed of a single cell composed of the solid polymer electrolyte 7 and the air electrode 8, it is composed of a single cell composed of the fuel electrode 64, the phosphoric acid electrolyte 65, and the air electrode 66. The difference is that a phosphoric acid fuel cell stack 67 is provided. In FIG. 3, the phosphoric acid fuel cell stack 67 is shown as being constituted by a single cell composed of a pair of fuel electrode 64, phosphoric acid electrolyte 65, and air electrode 66. The phosphoric acid fuel cell stack 67 is composed of a plurality of single cells.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In the present embodiment, the second reformer 53 is set to 700 ° C. or higher, and the steam reforming reaction of methane, which is an endothermic reaction, is performed, so that the cathode exhaust gas 69 and phosphorus of the phosphoric acid fuel cell stack The anode discharge gas 70 of the acid fuel cell stack is supplied to the reformer burner 54, and unreacted oxygen in the cathode discharge gas 69 of the phosphoric acid fuel cell stack and the fuel of the phosphoric acid fuel cell stack The necessary heat is supplied from the reformer burner 54 to the second reformer 53 by burning unreacted fuel and unreacted hydrogen in the polar exhaust gas 70. From the reformer burner 54, the reformer burner combustion exhaust gas 56 is discharged. In FIG. 3, in order to supply necessary heat to the second reformer 53, the cathode exhaust gas 69 of the phosphoric acid fuel cell stack and the anode exhaust gas 70 of the phosphoric acid fuel cell stack are used. Was supplied to the reformer burner 54 and burned, but any one of the cathode discharge gas 69 of the phosphoric acid fuel cell stack, the cathode discharge gas 44 of the solid oxide fuel cell stack, and the air 14 was used. At least one of the anode discharge gas 70 of the phosphoric acid fuel cell stack and the anode discharge gas 45 of the solid oxide fuel cell stack for discharge to the reformer burner 54, If unreacted fuel, unreacted hydrogen, and unreacted carbon monoxide are combusted, the second reforming is performed without supplying the natural gas 1 as a new fuel for combustion in the reformer burner 54. Hydrogen-rich reformer gas in vessel 53 Methane steam reforming reaction in the 22 to efficiently carried out, it is possible to reduce the methane concentration in the hydrogen-rich reformed gas 22.

  A part of the reformed gas 21 produced by the CO shift converter 4 and reduced in the concentration of carbon monoxide to 1% or less is used as a reformed gas 68 for a phosphoric acid fuel cell stack. Is supplied to the fuel electrode 64 of the phosphoric acid fuel cell stack 67. On the other hand, a part of the air 14 taken in by the air supply blower 12 is supplied to the air electrode 66 of the phosphoric acid fuel cell stack 67 as power generation air 85 of the phosphoric acid fuel cell stack. The supply amount of the power generation air 85 of the phosphoric acid fuel cell stack to the air electrode 66 of the phosphoric acid fuel cell stack 67 is determined based on the battery current of the fuel cell DC output 18 and the opening of the flow control valve 86. The flow rate control valve 86 is controlled based on the relationship of the degree (that is, the supply amount of the power generation air 85 of the phosphoric acid fuel cell stack) to meet the battery current of the fuel cell DC output 18. Set to value. The operating temperature of the phosphoric acid fuel cell stack 67 is generally 190 ° C., and the operating temperature is maintained by heat generated by the battery reaction.

  In the fuel electrode 64 of the phosphoric acid fuel cell stack 67, about 80% of the hydrogen contained in the reformed gas 68 for the phosphoric acid fuel cell stack is made into a solid polymer fuel by the action of the platinum-based electrode catalyst. As in the case of the battery cell stack, hydrogen ions and electrons are changed by the fuel electrode reaction shown in the chemical formula (9). Hydrogen ions generated at the fuel electrode 65 move inside the phosphate electrolyte and reach the air electrode 66. On the other hand, the electrons generated at the fuel electrode 64 move through the external circuit and reach the air electrode 66. Electric energy can be taken out as the fuel cell DC output 18 in the process of the electrons moving through the external circuit.

  In the air electrode 66 of the phosphoric acid fuel cell stack 67, hydrogen ions that have moved from the fuel electrode 64 to the air electrode 66 by the action of the platinum-based electrode catalyst, an external circuit is connected from the fuel electrode 64. The electrons that have moved to the air electrode 66 and the acid cords in the power generation air 85 of the phosphoric acid fuel cell stack supplied to the air electrode 66 are the same as in the case of the polymer electrolyte fuel cell stack. 10) It reacts by the air electrode reaction shown in the formula, and water is produced (produced with water vapor). Summarizing the formula (9) and the formula (10), the battery reaction of the phosphoric acid fuel cell stack 67 is expressed by the formula (11) as in the case of the polymer electrolyte fuel cell stack. It can be expressed as the reverse reaction of the electrolysis of water that can be produced from hydrogen and oxygen.

  The power generation air 85 of the phosphoric acid fuel cell stack is consumed by phosphoric acid after a part of oxygen is consumed by the air electrode reaction shown in the formula (10) at the air electrode 66 of the phosphoric acid fuel cell stack 67. It is discharged as the air electrode exhaust gas 69 of the fuel cell stack. On the other hand, the reformed gas 68 for the phosphoric acid fuel cell stack consumes about 80% of the hydrogen in the fuel electrode 64 of the phosphoric acid fuel cell stack 67 by the fuel electrode reaction shown in the formula (9). Then, it is discharged as the fuel electrode exhaust gas 70 of the phosphoric acid fuel cell stack.

Also in the third embodiment shown in FIG. 3, the solid oxide fuel cell stack 38 is compared to the conventional example shown in FIG. 16 as in the first and second embodiments shown in FIG. 1 and FIG. The temperature of the first reformer 52 is low because the temperature of the exhaust heat supplied from the solid oxide fuel cell stack 38 to the first reformer 52 is low when the operating temperature of the battery is as low as 600 to 800 ° C. Even when the methane concentration in the hydrogen-rich reformed gas 22 rises to 700 ° C. or lower and the second reformer 53 performs the steam reforming reaction of methane in the hydrogen-rich reformed gas 22. In addition, the reaction heat necessary for the steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 is generated by the natural gas 1 as a new fuel. Without using, the cathode exhaust gas of phosphoric acid fuel cell stack 9 and the anode discharge gas 70 of the phosphoric acid fuel cell stack are supplied by burning in the reformer burner 54, so that the solid oxide fuel cell stack 38 and the phosphoric acid fuel cell stack 67 It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used, and to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 4]

  FIG. 4 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the fourth embodiment. 4, the same components as those in FIGS. 16, 1, 2, and 3 described above are denoted by the same reference numerals, and description thereof is omitted. In FIG. 4, 71 is a fuel electrode exhaust gas of a solid oxide fuel cell stack in which the carbon monoxide concentration is reduced to 1% or less, and 72 is a fuel electrode of a solid oxide fuel cell stack for a CO selective oxidizer. Exhaust gas, 73 is a fuel electrode exhaust gas of a solid oxide fuel cell stack in which the concentration of carbon monoxide is reduced to the order of ppm, and 74 is a fuel electrode of a solid oxide fuel cell stack in which unreacted water vapor is condensed Exhaust gas, 75 is the anode discharge gas of the solid oxide fuel cell stack for recycling the desulfurizer, 76 is controlling the supply amount of the anode discharge gas 75 of the solid oxide fuel cell stack for recycling the desulfurizer The flow control valve 77 is an anode exhaust gas of a solid oxide fuel cell stack for a CO shift converter.

  The fuel cell power generation system of the present invention exemplified in Example 4 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a first reformer 52 and a second reformer are used instead of the reformer 3 as shown in FIG. The reformer 53 is provided with two reformers, the second reformer 53 is provided with a reformer burner 54, and a solid for a CO shift converter instead of the hydrogen-rich reformed gas 22. The difference is that the fuel electrode exhaust gas 77 of the oxide fuel cell stack is supplied to the shift converter 4.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, in the desulfurizer 2, the reforming catalyst of the first reformer 52 and the second reformer 53, the fuel electrode 6 of the polymer electrolyte fuel cell stack 9, and the solid oxide fuel cell. The sulfur content contained in the odorant such as mercaptan in the natural gas 1 which causes deterioration of the electrode catalyst of the fuel electrode 35 of the cell stack 38 is removed by adsorption by hydrodesulfurization. Specifically, sulfur and hydrogen are first reacted with a cobalt-molybdenum-based catalyst to generate hydrogen sulfide, and then hydrogen sulfide and zinc oxide are reacted to generate zinc sulfide to remove the sulfur content. In order to supply the hydrogen necessary for the production of water sulfidation, a part of the fuel electrode exhaust gas 71 of the solid oxide fuel cell stack in which the hydrogen-rich carbon monoxide concentration is reduced to 1% or less is desulfurized. This is recycled to the desulfurizer 2 as the fuel electrode exhaust gas 75 of the solid oxide fuel cell stack for recycler. The supply amount of the anode discharge gas 75 of the solid oxide fuel cell stack for recycling the desulfurizer is determined based on the preset opening degree of the flow control valve 27 (that is, the supply amount of natural gas 1) and the flow control valve 76. Natural gas by controlling the opening degree of the flow rate control valve 76 based on the relationship of the opening degree (that is, the supply amount of the fuel electrode exhaust gas 75 of the solid oxide fuel cell stack for recycling the desulfurizer). Set to a value commensurate with the supply amount of 1.

  The reformed gas 55 whose methane concentration has been reduced by the second reformer 53 is supplied to the fuel electrode 35 of the solid oxide fuel cell stack 38 to generate power in the solid oxide fuel cell stack 38. .

  The fuel cell exhaust gas 77 of the solid oxide fuel cell stack for the CO shift converter contains carbon monoxide that causes deterioration of the electrode catalyst of the fuel electrode 6 of the polymer electrolyte fuel cell stack 9. Therefore, the anode discharge gas 77 of the solid oxide fuel cell stack for the CO shift converter is supplied to the CO shift converter 4, and the anode discharge gas 77 of the solid oxide fuel cell stack for the CO shift converter is supplied. Reduce the carbon monoxide concentration to 1% or less. As described above, a part of the fuel electrode exhaust gas 71 of the solid oxide fuel cell stack in which the carbon monoxide concentration produced by the CO shift converter 4 is reduced to 1% or less is solid oxide for recycling the desulfurizer. It supplied to the desulfurizer 2 as the fuel electrode exhaust gas 75 of the physical fuel cell stack, and the remainder was supplied to the fuel electrode 6 of the solid polymer fuel cell stack 9 when the carbon monoxide concentration was 100 ppm or more. In order to reduce the carbon monoxide concentration on the order of ppm, the CO selective oxidizer 5 is used as the fuel electrode exhaust gas 72 of the solid oxide fuel cell stack for the CO selective oxidizer. Supply. The CO selective oxidizer 5 reduces the carbon monoxide concentration in the fuel electrode exhaust gas 72 of the solid oxide fuel cell for the CO selective oxidizer to the order of ppm.

  The supply amount of the CO selective oxidizer air 26 includes the preset opening degree of the flow control valve 27 (ie, the supply amount of natural gas 1) and the opening degree of the flow control valve 11 (ie, the CO selective oxidizer air 26). Based on the relationship of the supply amount), the opening degree of the flow control valve 11 is controlled to set a value corresponding to the supply amount of the natural gas 1.

  Unreacted water vapor contained in the fuel electrode exhaust gas 73 of the solid oxide fuel cell stack in which the carbon monoxide concentration produced by the CO selective oxidizer 5 is reduced to the order of ppm is reduced to 100 ° C. or less by the condenser 29. The condensed water 31 is recovered by cooling. The fuel electrode exhaust gas 74 of the solid oxide fuel cell stack in which the unreacted water vapor is condensed by the condenser 29 is supplied to the fuel electrode 6 of the polymer electrolyte fuel cell stack 9.

  In the fuel electrode 6 of the polymer electrolyte fuel cell stack 9, about platinum of the hydrogen contained in the fuel electrode exhaust gas 74 of the solid oxide fuel cell stack in which the unreacted water vapor is condensed by the action of the platinum-based electrode catalyst. 80% is converted into hydrogen ions and electrons by the fuel electrode reaction shown in the chemical formula (9). Hydrogen ions generated at the fuel electrode 6 move inside the solid polymer electrolyte 7 composed of a fluorine-based polymer having a sulfonic acid group such as Nafion and reach the air electrode 8. On the other hand, the electrons generated at the fuel electrode 6 travel through the external circuit and reach the air electrode 8. Electric energy can be taken out as the fuel cell DC output 18 in the process of the electrons moving through the external circuit.

In the fourth embodiment shown in FIG. 4, as in the first, second, and third embodiments shown in FIGS. 1, 2, and 3, as compared with the conventional example shown in FIG. When the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C., the temperature of the exhaust heat supplied from the solid oxide fuel cell stack 38 to the first reformer 52 is low. Even if the temperature of the first reformer 52 is lowered to 700 ° C. or lower and the methane concentration in the hydrogen-rich reformed gas 22 is increased, the second reformer 53 in the hydrogen-rich reformed gas 22 Hydrogen is produced by performing the steam reforming reaction of methane, and the reaction heat required for the steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 is Without using natural gas 1 as a new fuel, polymer electrolyte fuel cells Since the air electrode exhaust gas 13 of the tack and the fuel electrode exhaust gas 15 of the polymer electrolyte fuel cell stack are supplied by combustion in the reformer burner 54, the solid oxide fuel cell stack 38 and the polymer electrolyte are supplied. It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the fuel cell stack 9, and to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 5]

  FIG. 5 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the fifth embodiment. In FIG. 5, the same parts as those in FIGS. 16, 1, 2, 3, and 4 described above are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 5, reference numeral 78 denotes an anode exhaust gas of a solid oxide fuel cell stack for a hydrogen separator.

  The fuel cell power generation system of the present invention exemplified in Example 5 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that the first reformer 52 and the second reformer 3 instead of the reformer 3 as shown in FIG. The reformer 53 is provided with two reformers, and the second reformer 53 is provided with a reformer burner 54. Solid oxidation for a CO shift converter instead of the hydrogen-rich reformed gas 22 The difference is that the anode discharge gas 77 of the physical fuel cell stack is supplied to the shift converter 4, and the hydrogen separator 57 is provided in place of the CO selective oxidizer 5 and the condenser 29.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a part of the anode exhaust gas 71 of the solid oxide fuel cell stack in which the carbon monoxide concentration produced by the CO shift converter 4 is reduced to 1% or less is used as a solid oxide for a hydrogen separator. The fuel electrode stack 78 is supplied as a fuel electrode exhaust gas 78 to a hydrogen separator 57 having a hydrogen separation membrane such as a palladium membrane, and hydrogen 59 is separated. At that time, in order to perform efficient hydrogen separation, the anode discharge gas 78 of the solid oxide fuel cell stack for the hydrogen separator is pressurized as necessary.

In the fifth embodiment shown in FIG. 5 as well, as in the first, second, third, and fourth embodiments of the present invention shown in FIG. 1, FIG. 2, FIG. 3, and FIG. 16, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C., the solid oxide fuel cell stack 38 supplies the first reformer 52. Even if the temperature of the first reformer 52 decreases to 700 ° C. or lower due to the low temperature of the exhaust heat generated, the second reformer does not exceed the methane concentration in the hydrogen-rich reformed gas 22. Hydrogen is produced by performing a steam reforming reaction of methane in the hydrogen-rich reformed gas 22 at 53, and the methane in the hydrogen-rich reformed gas 22 in the second reformer 53 is produced. The reaction heat required for the steam reforming reaction can be achieved without using natural gas 1 as a new fuel. Since supplied by burning the air electrode exhaust gas 13 and the hydrogen separator exhaust gas 58 of the solid polymer fuel cell stack reformer burner 54, the solid oxide fuel cell stack 38 and the polymer electrolyte It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the fuel cell stack 9, and it is possible to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 6]

  FIG. 6 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a sixth embodiment. In FIG. 6, the same parts as those in FIGS. 16, 1, 2, 3, 4, and 5 described above are denoted by the same reference numerals, and description thereof is omitted. In FIG. 6, reference numeral 79 denotes an anode exhaust gas of a solid oxide fuel cell stack for a phosphoric acid fuel cell stack.

  The fuel cell power generation system of the present invention exemplified in Example 6 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that the first reformer 52 and the second reformer 3 instead of the reformer 3, as shown in FIG. The reformer 53 is provided with two reformers, and the second reformer 53 is provided with a reformer burner 54. Solid oxidation for a CO shift converter instead of the hydrogen-rich reformed gas 22 The fuel electrode cell stack stack fuel electrode exhaust gas 77 is supplied to the CO shift converter 4, and the CO selective oxidizer 5 and the condenser 29 are unnecessary, and the fuel electrode 6, the solid polymer electrolyte 7, and the air electrode 8. In place of the polymer electrolyte fuel cell stack 9 composed of a single cell made of a phosphoric acid fuel cell stack 67 composed of a single cell composed of a fuel electrode 64, a phosphoric acid electrolyte 65, and an air electrode 66. Different points are provided.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a part of the fuel electrode exhaust gas 71 of the solid oxide fuel cell stack whose carbon monoxide concentration is reduced to 1% or less is used as the solid oxide fuel for the phosphoric acid fuel cell stack. The fuel cell stack fuel electrode exhaust gas 79 is supplied to the fuel electrode 64 of the phosphoric acid fuel cell stack 67 to generate electricity.

Also in the present embodiment shown in FIG. 6, the first, second, third, fourth, and fifth embodiments shown in FIGS. 1, 2, 3, 4, and 5 Similarly, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. as compared with the conventional example shown in FIG. Even if the temperature of the first reformer 52 decreases to 700 ° C. or lower because the temperature of the exhaust heat supplied to the reactor 52 is low, the methane concentration in the hydrogen-rich reformed gas 22 increases. Hydrogen is produced by performing a steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the reformer 53, and in the hydrogen-rich reformed gas 22 in the second reformer 53. The reaction heat required for the steam reforming reaction of methane is to use natural gas 1 as a new fuel. However, since the cathode exhaust gas 69 of the phosphoric acid fuel cell stack and the anode exhaust gas 70 of the phosphoric acid fuel cell stack are supplied by combustion in the reformer burner 54, the solid oxide fuel cell It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel effectively used in the cell stack 38 and the phosphoric acid fuel cell stack 67, and to suppress a decrease in power generation efficiency of the fuel cell power generation system Is possible.
[Example 7]

  FIG. 7 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a seventh embodiment. 7, the same parts as those in FIGS. 16, 1, 2, 3, 4, 5, and 6 described above are denoted by the same reference numerals, and description thereof is omitted. In FIG. 7, 80 is the anode discharge gas of the solid oxide fuel cell stack for the second reformer, and 81 is the anode discharge gas of the solid oxide fuel cell stack with reduced methane concentration. .

  The fuel cell power generation system of the present invention exemplified in Example 7 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that the first reformer 52 and the second reformer 3 instead of the reformer 3, as shown in FIG. A reformer 53 is provided, and further, a reformer burner 54 is provided in the second reformer 53, and an anode exhaust gas 80 of a solid oxide fuel cell stack for the second reformer is provided. The difference is that the second reformer 53 is supplied.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In the present embodiment, when the power generation temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C., the temperature of the first reformer 52 is lowered from 700 ° C., and the relationship of thermodynamic equilibrium. Thus, a large amount of unreacted methane is contained in the reformed gas 22 rich in hydrogen. The hydrogen-rich reformed gas 22 is supplied to the fuel electrode 35 of the solid oxide fuel cell stack 38, and power generation of the solid oxide fuel cell stack 38 is performed. The fuel electrode exhaust gas 80 of the solid oxide fuel cell stack for the second reformer containing a large amount of unreacted methane is supplied to the second reformer 53 and acts by the charged reforming catalyst ( The steam reforming reaction of methane shown in the chemical formula 1) is performed to reduce the methane concentration in the fuel electrode exhaust gas 80 of the solid oxide fuel cell stack for the second reformer. The fuel electrode exhaust gas 81 of the solid oxide fuel cell stack in which the methane concentration is reduced is supplied to the CO shift converter 4.

Also in the seventh embodiment shown in FIG. 7, the first, second, third, fourth, and fourth embodiments shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5 and 6, the solid oxide fuel cell stack when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. as compared with the conventional example shown in FIG. 16. Since the temperature of the exhaust heat supplied from 38 to the first reformer 52 is low, the temperature of the first reformer 52 is lowered to 700 ° C. or lower, and the methane concentration in the hydrogen-rich reformed gas 22 is reduced. Even if it rises, hydrogen is produced by causing the second reformer 53 to perform a steam reforming reaction of methane in the anode electrode gas 80 of the solid oxide fuel cell stack for the second reformer. And a solid oxide fuel cell unit for the second reformer in the second reformer 53. The reaction heat necessary for the steam reforming reaction of methane in the fuel electrode exhaust gas 80 of the fuel is not newly used as the natural gas 1 as fuel, and the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and Since the fuel cell exhaust gas 15 of the polymer electrolyte fuel cell stack is supplied by being burned by the reformer burner 54, it is effective in the solid oxide fuel cell stack 38 and the polymer electrolyte fuel cell stack 9. It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel used, and to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 8]

  FIG. 8 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the eighth embodiment. In FIG. 8, the same parts as those in FIGS. 16, 1, 2, 3, 4, 4, 5, and 7 described above are denoted by the same reference numerals, and description thereof is omitted. .

  The fuel cell power generation system of the present invention exemplified in Example 8 will be described with reference to FIG. The fuel cell power generation system of this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that the first reformer 52 and the second reformer 3 are used instead of the reformer 3 as shown in FIG. The reformer 53 is provided, the reformer burner 54 is further provided in the second reformer 53, and the anode exhaust gas 80 of the solid oxide fuel cell stack for the second reformer is supplied to the first reformer 53. The difference is that the hydrogen is supplied to the second reformer 53 and the hydrogen separator 57 is provided in place of the CO selective oxidizer 5 and the condenser 29.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In the present embodiment, a part of the fuel electrode exhaust gas 71 of the solid oxide fuel cell stack in which the concentration of carbon monoxide, which is the exhaust gas of the CO shift converter 4, is reduced to 1% or less is used as a solid for a hydrogen separator. It is supplied to the hydrogen separator 58 as the fuel electrode exhaust gas 78 of the oxide fuel cell stack.

Also in the eighth embodiment shown in FIG. 8, the first, second, third, and fourth embodiments shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. As in Example 5, Example 6, and Example 7, when the power generation temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. as compared with the conventional example shown in FIG. Since the temperature of the exhaust heat supplied from the solid oxide fuel cell stack 38 to the first reformer 52 is low, the temperature of the first reformer 52 is lowered to 700 ° C. or lower and the hydrogen-rich reforming is performed. Even if the methane concentration in the gas 22 rises, the second reformer 53 performs the steam reforming reaction of methane in the anode exhaust gas 80 of the solid oxide fuel cell stack for the second reformer. Hydrogen is produced by carrying out the process, and the solid oxide form for the second reformer in the second reformer 53 The reaction heat necessary for the steam reforming reaction of methane in the fuel cell stack fuel electrode exhaust gas 80 does not use the natural gas 1 that is a new fuel, and the air electrode discharge of the polymer electrolyte fuel cell stack Since the gas 13 and the hydrogen separator exhaust gas 58 are supplied by being burned by the reformer burner 54, the fuel used effectively in the solid oxide fuel cell stack 38 and the solid polymer fuel cell stack 9 It is possible to suppress a decrease in the fuel utilization rate in terms of methane that indicates the ratio, and it is possible to suppress a decrease in the power generation efficiency of the fuel cell power generation system.
[Example 9]

  FIG. 9 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the ninth embodiment. 9, the same parts as those shown in FIGS. 16, 1, 2, 3, 4, 4, 5, 6, 7 and 8 described above are denoted by the same reference numerals, and the description thereof will be omitted. Is omitted.

  The fuel cell power generation system of the present invention exemplified in Example 9 will be described with reference to FIG. The fuel cell power generation system of the present embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a first reformer 52 and a second reformer are used instead of the reformer 3 as shown in FIG. The reformer 53 is provided, the reformer burner 54 is further provided in the second reformer 53, and the anode exhaust gas 80 of the solid oxide fuel cell stack for the second reformer is supplied to the first reformer 53. The point supplied to the second reformer 53, the CO selective oxidizer 5 and the condenser 29 are unnecessary, and the solid polymer constituted by the single cell comprising the fuel electrode 6, the solid polymer electrolyte 7 and the air electrode 8 is used. Instead of the fuel cell stack 9, a phosphoric fuel cell stack 67 composed of a single cell comprising a fuel electrode 64, a phosphoric acid electrolyte 65, and an air electrode 66 is provided.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a part of the anode discharge gas 71 of the solid oxide fuel cell stack produced by the CO shift converter 4 and having the carbon monoxide concentration reduced to 1% or less is used as a phosphoric acid fuel cell. The solid oxide fuel cell stack stack fuel electrode exhaust gas 79 is supplied to the fuel electrode 64 of the phosphoric acid fuel cell stack 67 as the fuel electrode exhaust gas 79, and the phosphoric acid fuel cell stack 67 generates power.

Also in the ninth embodiment shown in FIG. 9, the first embodiment, the second embodiment, the third embodiment shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. Similar to the fourth example, the fifth example, the sixth example, the seventh example, and the eighth example, the operation temperature of the solid oxide fuel cell stack 38 is 600 to 600 in comparison with the conventional example shown in FIG. When the temperature is as low as 800 ° C., the temperature of the first reformer 52 becomes 700 ° C. or lower because the temperature of the exhaust heat supplied from the solid oxide fuel cell stack 38 to the first reformer 52 is lowered. Even if the methane concentration in the hydrogen-rich reformed gas 22 decreases and increases, the second reformer 53 in the anode exhaust gas 80 of the solid oxide fuel cell stack for the second reformer Hydrogen is produced by performing a steam reforming reaction of methane, and the second reformer 53 in the second reformer 53 The reaction heat required for the steam reforming reaction of methane in the fuel electrode exhaust gas 80 of the solid oxide fuel cell stack for a reactor is not a new natural gas 1 as a fuel, but a phosphoric acid fuel cell. Since the stack cathode electrode gas 69 and the phosphoric acid fuel cell stack anode electrode gas 70 are supplied by combustion in the reformer burner 54, the solid oxide fuel cell stack 38 and the phosphoric acid fuel cell are supplied. It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the battery cell stack 67, and to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 10]

  FIG. 10 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the tenth embodiment. 10, the same parts as those shown in FIGS. 16, 1, 2, 3, 4, 4, 5, 6, 7, 8, and 9 are denoted by the same reference numerals. Will not be described. 10, 82 is a reformer, 83 is a reformer burner, 84 is a reformer burner combustion exhaust gas, and 87 is a fuel electrode exhaust gas of a solid oxide fuel cell stack for the reformer.

  The fuel cell power generation system of the present invention exemplified in Example 10 will be described with reference to FIG. The fuel cell power generation system of this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a solid oxide fuel cell for a reformer is used instead of the reformer 3 as shown in FIG. A reformer having a reformer burner 83 for supplying the fuel cell exhaust gas 87 of the cell stack and causing a steam reforming reaction of methane in the fuel cell exhaust gas 87 of the solid oxide fuel cell stack for the reformer. The difference is that the device 82 is provided.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a mixed gas 23 of water vapor and desulfurized natural gas is supplied to the fuel electrode 35 of the solid oxide fuel cell stack 38. In the fuel electrode 35 of the solid oxide fuel cell stack 38, the steam reforming reaction of hydrocarbons contained in the natural gas 1 is performed by the action of the fuel electrode catalyst, and hydrogen and carbon monoxide are generated. Hydrogen and carbon monoxide generated in the fuel electrode 35 are consumed on the spot by the fuel electrode reaction shown in the formulas (3) and (4), and the solid oxide fuel cell stack 38 is generated. . Since the hydrocarbon steam reforming reaction is an endothermic reaction, the heat generated by the solid oxide fuel cell stack 38 accompanying power generation is used as the reaction heat necessary for the hydrocarbon steam reforming reaction. However, when the operating temperature of the solid oxide fuel cell stack 38 is lower than 700 ° C., all hydrocarbons in the natural gas 1 are not converted into hydrogen and carbon monoxide, and thermodynamic equilibrium is achieved. Therefore, a large amount of unreacted methane is present in the anode exhaust gas 42 of the solid oxide fuel cell stack.

  Therefore, a part of the anode discharge gas 42 of the solid oxide fuel cell stack containing unreacted methane is transferred to the reformer 82 as the anode discharge gas 87 of the solid oxide fuel cell stack for the reformer. Supply. In the reformer 82, a solid oxide fuel for the reformer shown in the formula (1) is obtained by the action of a reforming catalyst made of a metal oxide such as alumina carrying a metal such as nickel or ruthenium filled. By performing the steam reforming reaction of methane in the fuel cell exhaust gas 87 of the battery cell stack, the fuel electrode exhaust gas 81 of the solid oxide fuel cell stack having a reduced methane concentration is produced. The steam reforming reaction of methane shown in the chemical formula (1) is an endothermic reaction, and the reaction heat necessary for the reaction is supplied to the reformer burner 83 and the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and the solid An anode exhaust gas 15 of the polymer electrolyte fuel cell stack is supplied, unreacted oxygen in the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack, and an anode exhaust gas of the polymer electrolyte fuel cell stack 15, the unreacted fuel and unreacted hydrogen in 15 are burned, and then supplied from the reformer burner 83 to the reformer 82. From the reformer burner 83, the reformer burner combustion exhaust gas 84 is discharged. A part of the fuel electrode exhaust gas 71 of the solid oxide fuel cell stack in which the concentration of carbon monoxide, which is the exhaust gas of the CO shift converter 4, is reduced to 1% or less is a solid oxide fuel for a CO selective oxidizer The fuel cell stack is supplied to the CO selective oxidizer 5 as the fuel electrode exhaust gas 72.

  In FIG. 10, in order to supply necessary heat to the reformer 82, the cathode discharge gas 13 of the polymer electrolyte fuel cell stack and the anode discharge gas 15 of the polymer electrolyte fuel cell stack are reformed. However, one or more of the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack, the air electrode exhaust gas 44 of the solid oxide fuel cell stack, and the air 14 are supplied. If the fuel electrode exhaust gas 15 of the polymer electrolyte fuel cell stack is supplied to the reformer burner 83 and oxygen, unreacted fuel and unreacted hydrogen are burned, the combustion of the reformer burner 83 is Therefore, the steam reforming reaction of methane in the anode discharge gas 87 of the solid oxide fuel cell stack for the reformer is efficiently performed by the reformer 82 without supplying the natural gas 1 as the fuel. Let It is possible to reduce the methane concentration in the fuel electrode in the exhaust gas 87 of the dexterity of the solid oxide fuel cell stack.

Also in the present embodiment shown in FIG. 10, the first embodiment, the second embodiment, and the second embodiment shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8 and 9. Similarly to Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, and Example 9, compared to the conventional example shown in FIG. 16, the solid oxide fuel cell stack Even when the methane concentration in the anode discharge gas 42 of the solid oxide fuel cell stack rises when the operation temperature of 38 is as low as 600 to 800 ° C., the reformer 82 uses the solid oxide for the reformer. Hydrogen is produced by performing a steam reforming reaction of methane in the anode discharge gas 87 of the fuel cell stack, and the reformer 82 uses the solid oxide fuel cell stack for the reformer. The reaction heat required for the steam reforming reaction of methane in the fuel electrode exhaust gas 87 is newly generated by fuel. Without using natural gas 1, the air electrode exhaust gas 13 of the polymer electrolyte fuel cell stack and the fuel electrode exhaust gas 15 of the polymer electrolyte fuel cell stack are supplied by burning in the reformer burner 83. Therefore, it is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the solid oxide fuel cell stack 38 and the polymer electrolyte fuel cell stack 9, and to generate fuel cell power generation. It is possible to suppress a decrease in power generation efficiency of the system.
[Example 11]

  FIG. 11 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as Example 11. In FIG. 11, the same parts as those shown in FIGS. 16, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are denoted by the same reference numerals. The description of those is omitted.

  The fuel cell power generation system of the present invention exemplified in Example 11 will be described with reference to FIG. The fuel cell power generation system of this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a solid oxide fuel cell for a reformer is used instead of the reformer 3, as shown in FIG. A reformer having a reformer burner 83 for supplying the fuel cell exhaust gas 87 of the cell stack and causing a steam reforming reaction of methane in the fuel cell exhaust gas 87 of the solid oxide fuel cell stack for the reformer. The difference is that the apparatus 82 is provided and the hydrogen separator 57 is provided instead of the CO selective oxidizer 5 and the condenser 29.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a part of the anode exhaust gas 71 of the solid oxide fuel cell stack in which the carbon monoxide concentration produced by the CO shift converter 4 is reduced to 1% or less is used as a solid oxide for a hydrogen separator. It is supplied to the hydrogen separator 57 as the fuel electrode exhaust gas 78 of the physical fuel cell stack.

Also in the present embodiment shown in FIG. 11, the first embodiment and the second embodiment shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. As in Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, and Example 10, compared with the conventional example shown in FIG. When the power generation temperature of the physical fuel cell stack 38 is as low as 600 to 800 ° C., the reformer 82 modifies the methane concentration in the fuel electrode exhaust gas 42 of the solid oxide fuel cell stack. Hydrogen is produced by carrying out a steam reforming reaction of methane in the anode discharge gas 87 of the solid oxide fuel cell stack for the grader, and the solid oxide for the reformer in the reformer 82 Necessary for Steam Reforming Reaction of Methane in Fuel Electrode Exhaust Gas 87 of Fuel Cell Without the use of natural gas 1 is newly fuel, since the supply by the combustion of the air electrode exhaust gas 13 and the hydrogen separator exhaust gas 58 of the solid polymer fuel cell stack reformer burner 83 The reduction in the fuel utilization rate in terms of methane, which indicates the proportion of fuel effectively used in the solid oxide fuel cell stack 38 and the solid polymer fuel cell stack 9, can be suppressed. It is possible to suppress a decrease in power generation efficiency.
[Example 12]

  FIG. 12 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the twelfth embodiment. 12, the same components as those in FIGS. 16, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 10, and 11 described above are denoted by the same reference numerals. The description of these items is omitted.

  The fuel cell power generation system of the present invention illustrated in Example 12 will be described with reference to FIG. The fuel cell power generation system according to this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a solid oxide fuel cell for a reformer is used instead of the reformer 3 as shown in FIG. A reformer having a reformer burner 83 for supplying the fuel cell exhaust gas 87 of the cell stack and causing a steam reforming reaction of methane in the fuel cell exhaust gas 87 of the solid oxide fuel cell stack for the reformer. A solid polymer fuel cell comprising a single cell comprising a fuel electrode 6, a solid polymer electrolyte 7, and an air electrode 8. Instead of the stack 9, a phosphoric acid fuel cell stack 67 composed of a single cell comprising a fuel electrode 64, a phosphoric acid electrolyte 65, and an air electrode 66 is provided.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a part of the anode discharge gas 71 of the solid oxide fuel cell stack produced by the CO shift converter 4 and having the carbon monoxide concentration reduced to 1% or less is used as a phosphoric acid fuel cell. As the fuel electrode exhaust gas 79 of the solid oxide fuel cell stack for the stack, it is supplied to the fuel electrode of the phosphoric acid fuel cell stack 67 and the phosphoric acid fuel cell stack 67 generates power. In order to perform the steam reforming reaction of methane, which is an endothermic reaction, by setting the reformer 82 at 700 ° C. or higher, the cathode exhaust gas 69 of the phosphoric acid fuel cell stack and the fuel of the phosphoric acid fuel cell stack The electrode exhaust gas 70 is supplied to the reformer burner 83, and unreacted oxygen in the air electrode exhaust gas 69 of the phosphoric acid fuel cell stack and unreacted in the fuel electrode exhaust gas 70 of the phosphoric acid fuel cell stack. The required heat is supplied from the reformer burner 83 to the reformer 82 by burning the fuel and unreacted hydrogen. From the reformer burner 83, the reformer burner combustion exhaust gas 56 is discharged.

  In FIG. 12, in order to supply necessary heat to the reformer 82, the cathode exhaust gas 69 of the phosphoric acid fuel cell stack and the anode exhaust gas 70 of the phosphoric fuel cell stack are reformed. Supplied to the burner 83 and burned, but one or more of the cathode exhaust gas 69 of the phosphoric acid fuel cell stack, the cathode exhaust gas 44 of the solid oxide fuel cell stack, and the air 14 When the anode discharge gas 70 of the phosphoric acid fuel cell stack is supplied to the reformer burner 83 and oxygen, unreacted fuel, and unreacted hydrogen are burned, the reformer burner 83 burns. Without supplying new natural gas 1 as fuel, the reformer 82 efficiently performs the steam reforming reaction of methane in the fuel electrode exhaust gas 87 of the solid oxide fuel cell stack for the reformer. For the reformer It is possible to reduce the methane concentration in the fuel electrode exhaust gas 87 of oxide fuel cell stack.

Also in this embodiment shown in FIG. 12, the first embodiment shown in FIGS. 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 10, and 11 is used. Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Example 10, Example 11, and Example 11 are shown in FIG. Compared to the conventional example, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C., the methane concentration in the anode discharge gas 42 of the solid oxide fuel cell stack increases. Also, hydrogen is produced by causing the reformer 82 to perform a steam reforming reaction of methane in the anode discharge gas 87 of the solid oxide fuel cell stack for the reformer. Of methane in anode exhaust gas 87 of solid oxide fuel cell stack for reformer The reaction heat required for the reforming reaction does not use the natural gas 1 as a new fuel, but the cathode exhaust gas 69 of the phosphoric acid fuel cell stack and the anode exhaust gas of the phosphoric acid fuel cell stack. 70 is supplied by burning it with the reformer burner 83, so that the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the solid oxide fuel cell stack 38 and the phosphoric acid fuel cell stack 67, is shown. The decrease in power generation efficiency of the fuel cell power generation system can be suppressed.
[Example 13]

  FIG. 13 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the thirteenth embodiment. In FIG. 13, the same thing as FIG.16, FIG.1, FIG.2, FIG.3, FIG.4, FIG.5, FIG.6, FIG.7, FIG.8, FIG.9, FIG. The same reference numerals are used, and the description of these components is omitted. In FIG. 13, 90 is a flow rate control valve for controlling the supply amount of the hydrogen-rich reformed gas 22 to the second reformer.

  The fuel cell power generation system of the present invention exemplified in Example 13 will be described with reference to FIG. The fuel cell power generation system of this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a first reformer 52 and a second reformer 3 are used instead of the reformer 3 as shown in FIG. The difference is that two reformers, the reformer 53, are provided, and the second reformer 53 is provided with a reformer burner 54.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In the present embodiment, a part of the hydrogen-rich reformed gas 22 produced by the first reformer 52 is supplied to the second reformer 53, and the rest of the solid oxide fuel cell stack 38. Supply to the fuel electrode 35. The supply amount of the hydrogen-rich reformed gas 22 to the second reformer 53 is determined based on the preset DC current of the fuel cell DC output 18 and the opening degree of the flow control valve 90 (that is, the second reformer Based on the relationship of the supply amount of the hydrogen-rich reformed gas 22 to 55), the opening degree of the flow control valve 90 is controlled to set a value commensurate with the direct current of the fuel cell direct current output 18. All the reformed gas 55 having a reduced methane concentration, which is the exhaust gas of the second reformer 53, is supplied to the CO shift converter 4. A part of the reformed gas 21 produced by the CO shift converter 4 and having the carbon monoxide concentration reduced to 1% or less is supplied to the CO selective oxidizer 5 as the reformed gas 34 for the CO selective oxidizer.

Also in this embodiment shown in FIG. 13, it is shown in FIGS. 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 10, 11, and 12. Same as Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Example 10, Example 11, and Example 12 In addition, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. as compared with the conventional example shown in FIG. Even if the temperature of the first reformer 52 decreases to 700 ° C. or lower due to the low temperature of the exhaust heat supplied to the gas 52, the methane concentration in the hydrogen-rich reformed gas 22 increases. Hydrogen is produced by causing the reformer 53 to perform a steam reforming reaction of methane in the hydrogen-rich reformed gas 22, and The reaction heat required for the steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 does not use the natural gas 1 that is a new fuel, and the polymer electrolyte fuel cell Since the cell electrode air exhaust gas 13 and the polymer electrolyte fuel cell stack fuel anode exhaust gas 15 are supplied by combustion in the reformer burner 54, the solid oxide fuel cell stack 38 and the solid high fuel cell stack 38 It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the molecular fuel cell stack 9, and it is possible to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 14]

  FIG. 14 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the fourteenth embodiment. 14 is the same as FIGS. 16, 1, 2, 3, 4, 5, 6, 7, 7, 8, 9, 10, 11, 12, and 13 described above. Are denoted by the same reference numerals, and description thereof is omitted.

  The fuel cell power generation system of the present invention illustrated in Example 14 will be described with reference to FIG. The fuel cell power generation system of this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that a first reformer 52 and a second reformer are used instead of the reformer 3 as shown in FIG. The reformer 53 is provided with two reformers, the second reformer 53 is provided with a reformer burner 54, and a hydrogen separator 57 instead of the CO selective oxidizer 5 and the condenser 29. Is different.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In the present embodiment, a part of the reformed gas 21 produced by the CO shift converter 4 and having the carbon monoxide concentration reduced to 1% or less is supplied to the hydrogen separator 57 as the reformed gas 63 for the hydrogen separator.

Also in this embodiment shown in FIG. 14, FIGS. 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 11, 12, and 13 are used. Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Example 10, Example 11, Example 12 shown in FIG. Similarly to Example 13, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. as compared to the conventional example shown in FIG. 16, the solid oxide fuel cell stack 38 Since the temperature of the exhaust heat supplied to the first reformer 52 is low, the temperature of the first reformer 52 is lowered to 700 ° C. or lower, and the methane concentration in the hydrogen-rich reformed gas 22 is increased. Even so, the second reformer 53 performs the steam reforming reaction of unreacted methane in the hydrogen-rich reformed gas 22. Thus, hydrogen is produced, and the reaction heat necessary for the steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 is to use the natural gas 1 that is a new fuel. In addition, the air electrode exhaust gas 13 and the hydrogen separator exhaust gas 58 of the polymer electrolyte fuel cell stack are supplied by being burned by the reformer burner 54, so that the solid oxide fuel cell stack 38 and the solid It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the molecular fuel cell stack 9, and it is possible to suppress a decrease in power generation efficiency of the fuel cell power generation system.
[Example 15]

  FIG. 15 is a diagram showing the configuration of the fuel cell power generation system of the present invention exemplified as the fifteenth embodiment. 15, FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 5, FIG. The same parts as those in FIG. 14 are denoted by the same reference numerals, and explanations thereof are omitted.

  The fuel cell power generation system of the present invention illustrated in Example 15 will be described with reference to FIG. The fuel cell power generation system of this embodiment is different from the conventional fuel cell power generation system shown in FIG. 16 in that the first reformer 52 and the second reformer 3 are used instead of the reformer 3 as shown in FIG. The reformer 53 is provided with two reformers, the second reformer 53 is provided with a reformer burner 54, the CO selective oxidizer 5 and the condenser 29 are unnecessary, and the fuel electrode 6 Instead of the solid polymer fuel cell stack 9 composed of a single cell composed of the solid polymer electrolyte 7 and the air electrode 8, it is composed of a single cell composed of the fuel electrode 64, the phosphate electrolyte 65 and the air electrode 66. The difference is that a phosphoric acid fuel cell stack 67 is provided.

  Next, the operation of the fuel cell power generation system of this embodiment will be described with reference to FIG. In this embodiment, a part of the reformed gas 21 produced by the CO shift converter and having the carbon monoxide concentration reduced to 1% or less is used as the phosphoric acid fuel cell reforming gas 68 for the phosphoric acid fuel cell stack. This is supplied to the fuel electrode 64 of the battery cell stack 67 and the phosphoric acid fuel cell stack 67 is generated.

  Also in this embodiment shown in FIG. 15, FIGS. 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 11, 12, 12, 13, And Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Example 10, Example 10, and Example 11 shown in FIG. Similarly to Example 12, Example 13, and Example 14, when the operating temperature of the solid oxide fuel cell stack 38 is as low as 600 to 800 ° C. as compared with the conventional example shown in FIG. Since the temperature of the exhaust heat supplied from the oxide fuel cell stack 38 to the first reformer 52 is low, the temperature of the first reformer 52 is lowered to 700 ° C. or lower and the hydrogen-rich reformed gas The steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 even if the methane concentration in the reactor 22 increases. Hydrogen is produced by carrying out the reaction, and the reaction heat necessary for the steam reforming reaction of methane in the hydrogen-rich reformed gas 22 in the second reformer 53 is newly produced as natural gas 1 as fuel. Without being used, the cathode exhaust gas 69 of the phosphoric acid fuel cell stack and the anode exhaust gas 70 of the phosphoric acid fuel cell stack are supplied by burning in the reformer burner 54, so that solid oxidation It is possible to suppress a decrease in the fuel utilization rate in terms of methane, which indicates the proportion of fuel that is effectively used in the physical fuel cell stack 38 and the phosphoric acid fuel cell stack 67, and to reduce the power generation efficiency of the fuel cell power generation system. Can be suppressed.

1 is a diagram illustrating a configuration of a fuel cell power generation system of the present invention exemplified as Example 1. FIG. FIG. 3 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a second embodiment. FIG. 5 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a third embodiment. FIG. 6 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a fourth embodiment. FIG. 6 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a fifth embodiment. FIG. 10 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a sixth embodiment. FIG. 10 is a diagram illustrating a configuration of a fuel cell power generation system of the present invention exemplified as a seventh embodiment. FIG. 10 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as an eighth embodiment. FIG. 10 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as a ninth embodiment. FIG. 10 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as Example 10; FIG. 10 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as Example 11; FIG. 16 is a diagram showing a configuration of a fuel cell power generation system of the present invention exemplified as Example 12; FIG. 16 shows a configuration of a fuel cell power generation system of the present invention exemplified as Example 13; The figure which shows the structure of the fuel cell power generation system of this invention illustrated as Example 14. FIG. The figure which shows the structure of the fuel cell power generation system of this invention illustrated as Example 15. FIG. The figure which shows the structure of the conventional fuel cell power generation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Natural gas 2 Desulfurizer 3 Reformer 4 CO shift converter 5 CO selective oxidizer 6 Fuel electrode 7 Solid polymer electrolyte 8 Air electrode 9 Polymer electrolyte fuel cell stack 10 Flow control valve 11 Flow control valve 12 Air supply Blower 13 Air electrode exhaust gas 14 of polymer electrolyte fuel cell stack 14 Air 15 Fuel electrode exhaust gas 16 of polymer electrolyte fuel cell stack 16 Output adjustment device 17 Load 18 Fuel cell DC output 19 Transmission end AC output 20 Reformed gas 21 with carbon oxide concentration reduced to the order of ppm Reformed gas 22 with carbon monoxide concentration reduced to 1% or less Hydrogen-rich reformed gas 23 Mixed gas of steam and desulfurized natural gas 24 Desulfurized natural gas 25 Air for power generation of polymer electrolyte fuel cell stack 26 Air for CO selective oxidizer 27 Flow control valve 28 Condensation of unreacted water vapor Reformed gas 29 Condenser 30 Water produced by battery reaction 31 Condensed water 32 Reformed gas for desulfurizer recycling 33 Flow control valve 34 Reformed gas for CO selective oxidizer 35 Fuel electrode 36 Solid oxide electrolyte 37 Air electrode 38 Solid oxide Fuel cell stack 39 Power generation air of solid oxide fuel cell stack 40 Flow rate control valve 41 Fuel electrode exhaust gas of solid oxide fuel cell stack for reformer recycling Solid oxide fuel cell stack Fuel electrode exhaust gas 43 Flow control valve 44 Air electrode exhaust gas 45 of solid oxide fuel cell stack Fuel electrode exhaust gas 46 of solid oxide fuel cell stack for discharge 46 Flow control valve 47 Flow control valve 48 Output adjustment Device 49 Load 50 Fuel cell DC output 51 Transmission end AC output 52 First reformer 53 Second reformer 54 Reformer bar -55 55 Reformed gas with reduced methane concentration 56 Reformer burner combustion exhaust gas 57 Hydrogen separator 58 Hydrogen separator exhaust gas 59 Hydrogen 60 Unreacted hydrogen 61 Purge valve 62 Purge gas 63 Reformed gas for hydrogen separator 64 Fuel Electrode 65 Phosphate electrolyte 66 Air electrode 67 Phosphoric acid fuel cell stack 68 Reformed gas 69 for phosphoric acid fuel cell stack Air cathode exhaust gas 70 of phosphoric acid fuel cell stack of phosphoric acid fuel cell stack Fuel electrode exhaust gas 71-Fuel electrode exhaust gas 72 of a solid oxide fuel cell stack whose carbon oxide concentration is reduced to 1% or less 72 Fuel electrode exhaust gas 73 of a solid oxide fuel cell stack for a CO selective oxidizer Fuel electrode exhaust gas 74 of solid oxide fuel cell stack with reduced carbon monoxide concentration on the order of ppm 74 Unreacted water vapor Condensed solid oxide fuel cell stack anode discharge gas 75 Desulfurizer solid oxide fuel cell stack anode discharge gas 76 Flow control valve 77 Solid oxide fuel for CO shift converter Battery cell stack anode discharge 78 Solid oxide fuel cell stack anode discharge gas 79 for hydrogen separator Solid oxide fuel cell stack anode discharge 80 for phosphoric acid fuel cell stack Fuel electrode exhaust gas 81 of solid oxide fuel cell stack for second reformer Fuel electrode exhaust gas 82 of solid oxide fuel cell stack with reduced methane concentration 82 Reformer 83 Reformer burner 84 Reformer burner combustion exhaust gas 85 Phosphoric acid fuel cell stack power generation air 86 Flow control valve 87 Solid oxide fuel cell for reformer Pond cell stack fuel electrode exhaust gas 88 Flow control valve 89 Flow control valve 90 Flow control valve

Claims (17)

In a fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by a steam reforming reaction of fuel with oxygen,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in hydrogen-rich reformed gas having a reduced methane concentration discharged from the first reformer into carbon dioxide and hydrogen by reacting with steam;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A fuel cell power generation system comprising: a second fuel cell stack that generates power by electrochemically reacting hydrogen in exhaust gas of the CO selective oxidizer with oxygen. In a fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by a steam reforming reaction of fuel with oxygen,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon dioxide and hydrogen by reacting carbon monoxide in the hydrogen-rich reformed gas with reduced methane concentration discharged from the first reformer with steam;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A fuel cell power generation system comprising: a second fuel cell stack that generates power by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in hydrogen-rich reformed gas having a reduced methane concentration discharged from the first reformer into carbon dioxide and hydrogen by reacting with steam;
A fuel cell power generation system comprising: a second fuel cell stack for generating power by electrochemically reacting hydrogen in exhaust gas of the CO shift converter with oxygen. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas into carbon dioxide and hydrogen by reacting with water vapor;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A fuel cell power generation system comprising: a second fuel cell stack that generates power by electrochemically reacting hydrogen in exhaust gas of the CO selective oxidizer with oxygen. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas into carbon dioxide and hydrogen by reacting with water vapor;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A fuel cell power generation system comprising: a second fuel cell stack that generates power by electrochemically reacting the hydrogen and oxygen separated by the hydrogen separator . In a fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by a steam reforming reaction of fuel with oxygen,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
Performing power generation by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen in hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer , First fuel for supplying exhaust heat generated along with power generation to the first reformer and supplying fuel electrode exhaust gas containing water vapor generated during power generation to the first reformer A battery cell stack;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas into carbon dioxide and hydrogen by reacting with water vapor;
A fuel cell power generation system comprising: a second fuel cell stack for generating power by electrochemically reacting hydrogen in exhaust gas of the CO shift converter with oxygen. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with water vapor;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A second fuel cell stack that generates electricity by electrochemically reacting hydrogen in the exhaust gas of the CO selective oxidizer with oxygen;
I have a,
The reformer burner, fuel cell power generation system characterized der Rukoto those combusting said second fuel cell stack cathode exhaust gas and the fuel electrode exhaust gas. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with water vapor;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A second fuel cell stack for generating electricity by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen;
I have a,
The reformer burner, fuel cell power generation system characterized der Rukoto those burning a portion of the second fuel cell the air electrode exhaust gas in the cell stack hydrogen separator exhaust gas. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with water vapor;
A second fuel cell stack for generating electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen;
I have a,
The reformer burner, fuel cell power generation system characterized der Rukoto those combusting said second fuel cell stack cathode exhaust gas and the fuel electrode exhaust gas. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
At the fuel electrode, hydrogen and carbon monoxide are generated by a steam reforming reaction of the fuel, and power is generated by electrochemically reacting the hydrogen or the hydrogen and the carbon monoxide with oxygen. The generated heat is consumed as reaction heat necessary for the steam reforming reaction of the fuel at the fuel electrode, and the fuel electrode exhaust gas containing water vapor generated with the power generation is supplied to the fuel electrode. A first fuel cell stack;
A reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the reformer into carbon dioxide and hydrogen by reacting with water vapor;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A second fuel cell stack that generates electricity by electrochemically reacting hydrogen and oxygen in the exhaust gas of the CO selective oxidizer;
I have a,
The reformer burner, fuel cell power generation system characterized der Rukoto those combusting said second fuel cell stack cathode exhaust gas and the fuel electrode exhaust gas. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
At the fuel electrode, hydrogen and carbon monoxide are generated by a steam reforming reaction of the fuel, and power is generated by electrochemically reacting the hydrogen or the hydrogen and the carbon monoxide with oxygen. The generated heat is consumed as reaction heat necessary for the steam reforming reaction of the fuel at the fuel electrode, and the fuel electrode exhaust gas containing water vapor generated with the power generation is supplied to the fuel electrode. A first fuel cell stack;
A reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas with reduced methane concentration discharged from the reformer into carbon dioxide and hydrogen by reacting with water vapor;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A second fuel cell stack for generating electricity by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen;
I have a,
The reformer burner, fuel cell power generation system characterized der Rukoto those burning a portion of the second fuel cell the air electrode exhaust gas in the cell stack hydrogen separator exhaust gas. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
At the fuel electrode, hydrogen and carbon monoxide are generated by a steam reforming reaction of the fuel, and power is generated by electrochemically reacting the hydrogen or the hydrogen and the carbon monoxide with oxygen. The generated heat is consumed as reaction heat necessary for the steam reforming reaction of the fuel at the fuel electrode, and the fuel electrode exhaust gas containing water vapor generated with the power generation is supplied to the fuel electrode. A first fuel cell stack;
A reformer provided with a reformer burner for producing a fuel electrode exhaust gas having a reduced methane concentration by a steam reforming reaction of methane in the fuel electrode exhaust gas;
A CO shift converter that converts carbon monoxide in the fuel electrode exhaust gas having a reduced methane concentration discharged from the reformer into carbon dioxide and hydrogen by reacting with water vapor;
A second fuel cell stack for generating electricity by electrochemically reacting hydrogen in the exhaust gas of the CO shift converter with oxygen;
I have a,
The reformer burner, fuel cell power generation system characterized der Rukoto those combusting said second fuel cell stack cathode exhaust gas and the fuel electrode exhaust gas. In a fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by a steam reforming reaction of fuel with oxygen,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
A CO shift converter that converts carbon monoxide in the hydrogen-rich reformed gas with a reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with steam;
A CO selective oxidizer that oxidizes carbon monoxide in the exhaust gas of the CO shift converter with oxygen to convert it into carbon dioxide;
A fuel cell power generation system comprising: a second fuel cell stack that generates power by electrochemically reacting hydrogen in exhaust gas of the CO selective oxidizer with oxygen. In a fuel cell power generation system that generates power by electrochemically reacting hydrogen generated by a steam reforming reaction of fuel with oxygen,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
A CO shift converter that converts carbon monoxide in the hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with steam;
A hydrogen separator for selectively separating hydrogen in the exhaust gas of the CO shift converter;
A fuel cell power generation system comprising: a second fuel cell stack that generates power by electrochemically reacting the hydrogen separated by the hydrogen separator with oxygen. In a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen and oxygen produced by a steam reforming reaction of fuel,
A first reformer for producing a hydrogen-rich reformed gas by a steam reforming reaction of the fuel;
The hydrogen-rich reformed gas discharged from the first reformer generates power by electrochemically reacting hydrogen or hydrogen and carbon monoxide with oxygen, and is generated along with the power generation. A first fuel cell stack for supplying exhaust heat to the first reformer and supplying an anode exhaust gas containing water vapor generated with the power generation to the first reformer;
A second reformer burner for producing a hydrogen-rich reformed gas having a reduced methane concentration by a steam reforming reaction of methane in the hydrogen-rich reformed gas discharged from the first reformer; A reformer of
A CO shift converter that converts carbon monoxide in the hydrogen-rich reformed gas with reduced methane concentration discharged from the second reformer into carbon dioxide and hydrogen by reacting with steam;
A fuel cell power generation system comprising: a second fuel cell stack for generating power by electrochemically reacting hydrogen in exhaust gas of the CO shift converter with oxygen.   The fuel cell power generation system according to any one of claims 1 to 15, wherein the first fuel cell stack is a solid oxide fuel cell stack, and the second fuel cell stack is A fuel cell power generation system comprising a polymer electrolyte fuel cell stack.   The fuel cell power generation system according to any one of claims 1 to 15, wherein the first fuel cell stack is a solid oxide fuel cell stack, and the second fuel cell stack is A fuel cell power generation system comprising a phosphoric acid fuel cell stack.

Images