JP2010073407A - Reforming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost by eliminating facilities such as a combustion type steam generator and a blower for oxidation air supply in a reforming system and by simplifying a system constitution. <P>SOLUTION: The reforming system supplies hydrogen-rich reforming gas generated by a self-oxidation inside heating type reformer 1 to a fuel cell 8. The reforming system includes: a material gas supply system 20, which is provided with a closed type humidifying tank 33 in a cooling system 9 for circulating the fuel cell 8, and supplies the material gas for reforming gas generation by blowing in retained water in the humidifying tank 33; and a material gas-steam mixture supply system 21 for supplying mixture of the material gas and steam accumulated in an upper space of the humidifying tank 33 to the reformer 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reforming system that supplies a fuel cell with hydrogen-rich reformed gas generated by a self-oxidation internal heating type reformer.

  Conventionally, a reformer provided with a reformer that generates a hydrogen-rich reformed gas by steam reforming a mixture of a source gas and steam (hereinafter referred to as a source-steam mixture) in the presence of a reforming catalyst. It has been known. The hydrogen-rich reformed gas obtained in the reformer further reduces the small amount of CO (carbon monoxide) contained in the CO reduction means to a few ppm level, and converts the resulting high-purity reformed gas into a solid. It is supplied to polymer electrolyte type fuel cells.

As the source gas, hydrocarbons such as methane, aliphatic alcohols such as methanol, ethers such as dimethyl ether, natural gas, etc. can be used. So-called 13A) including ethane, propane, butane and the like is generally used. The reaction formula of steam reforming in such a reformer can be expressed as CH ₄ + 2H ₂ O → CO ₂ + 4H ₂ when methane is used as a raw material gas, for example, and a preferable reforming reaction temperature is 650 to 750. It is in the range of ° C.

There are an external heating type and an internal heating type as a system for supplying heat necessary for the reaction of the reformer. The external heating type reformer is provided with a heating unit outside, and a reformed gas is generated by reacting a raw material gas and water vapor with the heat source. The internal heating type reformer is provided with a partial oxidation reaction layer on the supply side (upstream side), and the reforming catalyst layer disposed on the downstream side using the heat generated in the partial oxidation reaction layer is brought to the reforming reaction temperature. Heating is performed, and a steam reforming reaction is performed in the heated reforming catalyst layer to generate a hydrogen-rich reformed gas. This partial oxidation reaction can be represented by CH ₄ + 1/2 · O ₂ → CO + 2H ₂ , and the preferred partial oxidation reaction temperature is in the range of 250 ° C. or higher.

  For example, Patent Documents 1 and 2 describe a self-oxidation internal heating type reformer as an improvement of the internal heating type reformer. The reformers of Patent Documents 1 and 2 include, for example, a preliminary reforming chamber and a main reforming chamber. The preliminary reforming chamber is provided with a raw material-steam mixture supply unit, a reforming catalyst layer, and a discharge unit. The reforming chamber is provided with a supply unit communicating with the discharge unit, a supply unit for oxidized air, a mixed catalyst layer in which the reforming catalyst and the oxidation catalyst are mixed, a shift catalyst layer, and a discharge unit. In order to extend the useful life of the catalyst and the like charged in the reformer, it is necessary to supply after removing (desulfurizing) the sulfur component contained in the fuel such as city gas to a low concentration of 1 ppb or less. Therefore, a desulfurizer is provided in the raw material gas supply system.

  FIG. 3 is a process flow of a conventional reforming system in which a hydrogen-rich reformed gas is generated and supplied to a fuel cell by a self-oxidation internal heating type reformer. In FIG. 3, 1 is a self-oxidation internal heating type reformer, 2 is a desulfurizer, 3 is a steam generator, 4 is a feed water pump, 5 is a blower, and 6 is a mixer that mixes a raw material gas consisting of an ejector and steam. , 7 is a CO reducer, 8 is a fuel cell, 9 is a cooling water system, 10 is a cooling water tank, 11 and 12 are pumps, 13 is a hot water storage tank, 14 is a blower, 15 is a regulating valve for adjusting oxidized air, 16 Is a temperature controller, 17 is a temperature controller, 18 is a temperature detector, and a to o are pipes.

  A self-oxidation internal heating type reformer 1 (hereinafter simply referred to as the reformer 1) is supplied with a mixture of a raw material gas and water vapor. After the raw material gas is desulfurized by the desulfurizer 2, the raw material gas is supplied to the mixer 6 through the pipe a, and the water vapor is supplied from the water vapor generator 3 to the mixer 6 through the pipe d. The steam generator 3 has a combustion part and an evaporation part. The combustion part is supplied with air from a pipe c provided with an anode exhaust gas containing hydrogen and a blower 5 from a fuel cell 8 through a pipe i to generate combustion gas. Water such as pure water is supplied to the evaporating section from the pipe b provided with the pump 4, and is heated by the combustion gas to generate water vapor. The combustion section is supplied with combustion fuel from the pipe j as necessary.

  The reformer 1 includes a mixed catalyst layer in which at least a reforming catalyst and an oxidation catalyst are mixed, and a shift catalyst layer. The reformer 1 is supplied with a mixture of raw material gas and water vapor from the mixer 6 and is provided with a regulating valve 15. Oxidation air is supplied from f. Part of the raw material gas is oxidized (combusted) by oxygen in the air in the presence of the oxidation catalyst of the mixed catalyst layer to maintain the mixed catalyst layer at the reforming temperature.

  The reforming temperature is detected by the temperature detector 18 and the detected value is transmitted to the temperature controller 17. The temperature controller 17 controls the amount of air for oxidation by adjusting the adjustment valve 15 so that the detected temperature is maintained at a preset value. The temperature control unit 16 is configured by the temperature detector 18 and the temperature controller 17.

  The hydrogen-rich reformed gas generated in the reformer 1 is supplied to the CO reducer 7 from the pipe g, and after reducing the CO remaining in the reformed gas to the ppm level, the fuel cell 8 is supplied from the pipe h. Supplied to the anode side. Further, oxygen (air) is supplied to the cathode side of the fuel cell 8 from a pipe k provided with a blower 14, and power is generated by reaction between hydrogen contained in the reformed gas and oxygen in the air.

  A part of the oxygen in the air supplied to the cathode side of the fuel cell 8 is consumed by the power generation action, and the air having a reduced oxygen concentration is discharged to the outside as a cathode exhaust gas from the pipe l. On the other hand, a part of the hydrogen in the reformed gas supplied to the anode side of the fuel cell is consumed by the power generation action, and the reformed gas having a reduced hydrogen concentration is discharged from the pipe i as an anode exhaust gas, and a steam generator 3 is supplied as fuel.

  Since the internal temperature of the fuel cell 8 rises due to power generation, it is necessary to cool the fuel cell 8 with cooling water. The cooling action is performed by circulating the cooling water by the cooling water system 9. The cooling water system 9 includes a cooling water tank 10, a supply side pipe n provided with a pump 11, a return side pipe m provided with a hot water storage tank 13, a makeup water pipe o provided with a pump 12, and the like. The water stored in the cooling water tank 10 is supplied to the fuel cell 8 via the pipe n by the pump 11, and the cooling water heated and heated in the fuel cell 8 passes through the pipe m provided with the hot water storage tank 13. Return to.

  In the conventional reforming system shown in FIG. 3, steam for reforming is generated using the steam generator 3. However, such a steam generator 3 requires facilities such as a combustion fuel and air supply system and a water supply system. Therefore, instead of providing the combustion-type steam generator 3, a system is provided in which a steam generator that generates steam with the cooling water heated by the fuel cell 8 is provided, and the generated steam is supplied to the reformer 1. It is proposed in Document 3.

JP 2001-192201 A JP-A-2005-149860 JP-A-6-333588

In the system described in Patent Document 3, waste heat from a phosphoric acid fuel cell is supplied to a steam generator, and steam generated at the pressure of about 1 Kg / cm ² G and city gas as a raw material gas are mixed. The mixture is then fed to the reformer. At that time, since it is necessary to uniformly mix the city gas and water vapor, the pressure of the city gas supplied at 250 mmH ₂ O · G from the city gas supply system is usually 1 Kg / cm ² G of water vapor pressure with a pressure pump. It is supplied to the mixer after the pressure is increased to. However, the use of such a mixer has a problem that the system becomes complicated and the cost increases.

  Further, when mixing reformed steam, a steam control valve for controlling a predetermined amount of steam is required. Generally, since an existing steam control valve is for a large plant, for example, a fuel cell power plant of 10 kW class or less However, there is a problem not only in water vapor flow rate control accuracy but also in cost. In particular, in the 1 kW class household fuel cell system currently being developed in Japan, the steam supply for reforming is extremely small, and there is no steam control valve that meets the specifications in terms of technology and cost. There is a problem that system design does not hold. Therefore, it is desirable to realize a method of generating reforming steam by using the exhaust heat of the high temperature operation fuel cell main body (100 ° C. or higher) easily and at low cost without using the steam control valve. It was rare.

  SUMMARY OF THE INVENTION Accordingly, it is a first object of the present invention to provide a new reforming system in which a combustion-type steam generator and a raw material gas / steam mixer are omitted. And Furthermore, a second object of the present invention is to provide a reforming system that simplifies the air supply system for oxidation required by the self-oxidation internal heating type reformer. Furthermore, the present invention eliminates the combustion-type steam generator and the raw material gas / steam mixer, and simplifies the air supply system for oxidation required by the self-oxidation internal heating type reformer. It is a third object to provide

  A first reforming system of the present invention that solves the above problem is a reforming system that supplies a fuel cell with a hydrogen-rich reformed gas generated by a self-oxidation internal heating type reformer. And, a closed humidification tank is provided in the cooling system that circulates the fuel cell, a raw material gas supply system that supplies a raw material gas for generating reformed gas into the stored water of the humidifying tank, and an upper space of the humidifying water tank A raw material gas-water vapor mixture supply system is provided for supplying a mixture of the raw material gas and water vapor staying in the reformer (claim 1).

  In a preferred embodiment of the reforming system, the fuel cell is configured such that the steam / carbon molar ratio (S / C) of the mixture of the raw material gas and the steam generated in the cooling water tank is 2.5 to 3. Thus, a high-temperature fuel cell capable of maintaining the temperature of the stored water in the humidifying tank can be obtained.

  A second reforming system of the present invention that solves the above-described problems is a reforming system that supplies a fuel cell with hydrogen-rich reformed gas generated by a self-oxidation internal heating type reformer. An oxidizing air supply system is provided for supplying cathode exhaust gas of the fuel cell as the oxidizing air for the reformer (claim 3).

  In a preferred embodiment of the reforming system, an adjustment valve for adjusting the flow rate of the cathode exhaust gas is provided in the oxidizing air supply system, and the flow rate adjustment is performed so as to maintain the reforming temperature of the reformer at a preset value. A temperature control device for controlling the valve may be provided (claim 4).

  A third reforming system of the present invention that solves the above problem is a reforming system that supplies a fuel cell with a hydrogen-rich reformed gas generated by a self-oxidation internal heating type reformer. And, a closed humidification tank is provided in the cooling system that circulates the fuel cell, a raw material gas supply system for supplying the raw material gas for generating reformed gas into the stored water of the humidification tank, and an upper space of the humidification tank A source gas-steam mixture supply system for supplying a mixture of source gas and water vapor staying in the reformer to the reformer is provided, and further, an oxidized air supply for supplying cathode exhaust gas of the fuel cell as air for oxidation of the reformer A reforming system comprising a system (Claim 5).

  According to a first aspect of the present invention, there is provided a reforming system for supplying a fuel cell with a hydrogen-rich reformed gas generated by a self-oxidation internal heating type reformer. A closed-type humidification tank is provided in the circulating cooling system, a raw material gas supply system for supplying a raw material gas for generating reformed gas into the water stored in the humidifying tank, and a raw material gas staying in the upper space of the humidifying tank; A feed gas-steam mixture supply system for supplying a steam mixture to the reformer is provided.

  In the above reforming system, the cooling water discharged from the fuel cell is stored in the closed humidification tank as stored water in a saturated vapor pressure state. When a raw material gas such as city gas is blown into the high-temperature storage water by bubbling or the like, the saturated storage water is added to the raw material gas, and a mixture of the raw material gas and water vapor with a predetermined steam / carbon ratio (S / C) Stays in the upper space of the humidification tank. That is, the humidification tank acts as a humidifier for the source gas. By supplying this mixture of raw material gas and water vapor to the reformer through the raw material gas-water vapor mixture supply system, the combustion type water vapor generator and the raw material gas and water vapor mixer can be omitted. Therefore, the system configuration is simplified and miniaturized, which is advantageous in terms of cost.

  In the above reforming system, the steam / carbon molar ratio (S / C) of the mixture of the raw material gas and the steam generated in the cooling water tank is 2.5 to 3 as described in claim 2. By adopting a high-temperature fuel cell that can maintain the temperature of the stored water in the humidifying tank, a mixture of the raw material gas and water vapor having a predetermined S / C can be more easily generated in the humidifying tank.

  A reforming system according to a second aspect of the present invention is the reforming system for supplying the fuel cell with the hydrogen-rich reformed gas generated by the auto-oxidation internal heating type reformer. An oxidizing air supply system for supplying cathode exhaust gas as oxidizing air for the reformer is provided.

  In the above reforming system, the cathode exhaust gas containing oxygen is used for the oxidation of the self-oxidation internal heating type reformer, so that equipment such as a supply blower for oxidizing air for supplying to the reformer is omitted. can do. Therefore, the system configuration is simplified and miniaturized, which is advantageous in terms of cost.

  In the reforming system, as described in claim 4, an adjustment valve for adjusting the flow rate of the cathode exhaust gas is provided in the oxidizing air supply system so that the reforming temperature of the reformer is maintained at a preset value. A temperature control device for controlling the flow rate adjusting valve can be provided.

  During the operation of the reforming system, if the power generation amount (load amount) of the fuel cell changes, it is necessary to change the amount of reformed gas supplied from the reformer to the anode side and the amount of air supplied to the cathode side accordingly. is there. The reforming reaction is an endothermic reaction, and its heat balances with the heat source supplied by the oxidation reaction. Therefore, when the reformed gas supplied to the fuel cell increases, the reforming temperature decreases if the amount of oxygen for oxidation is constant. Then, the temperature control device is operated to increase the flow rate of the cathode exhaust gas so as to recover the heat balance.

  On the other hand, since the air supply system to the cathode side of the fuel cell and the oxidized air supply system from the cathode side to the reformer are connected to each other by piping or the like, the flow rate of the oxidized air supply system is adjusted by the adjustment valve as described above. Is increased, the amount of air supplied to the cathode side of the fuel cell is also increased accordingly. Thus, the air supply balance that can follow the load fluctuation of the fuel cell can be maintained only by controlling the temperature of the reformer.

  According to a third reforming system of the present invention for solving the above-mentioned problem, as described in claim 5, a reforming system for supplying a fuel cell with hydrogen-rich reformed gas generated by a self-oxidation internal heating type reformer. In the quality system, a closed humidification tank is provided in the cooling system that circulates the fuel cell, and a raw material gas supply system that supplies the raw gas for reforming gas generation into the stored water of the humidification tank, and the humidification tank Provided with a raw material-steam mixture supply system for supplying a mixture of raw material gas and water vapor staying in the upper space to the reformer, and further, oxidized air for supplying cathode exhaust gas of the fuel cell as oxidizing air for the reformer A supply system is provided.

  According to the above reforming system, both the effects of the first reforming system and the third reforming system of the present invention are combined, and the system configuration is further simplified and miniaturized by a synergistic effect thereof. The cost is also very advantageous.

  Next, the best mode for carrying out the present invention will be described. FIG. 1 is a process flow diagram showing a first embodiment of a reforming apparatus of the present invention. In addition, the same code | symbol is attached | subjected to the same part as FIG. 2 mentioned above, and the overlapping description is abbreviate | omitted.

The reformer 1 is a self-oxidation internal heating type reformer, for example, has a double cylinder structure, a reforming catalyst layer is arranged in the outer cylinder, and a mixture in which the reforming catalyst and the oxidation catalyst are mixed in the inner cylinder A catalyst layer and a shift catalyst layer are disposed. As reforming catalysts, Ni-based materials such as NiO-A1 ₂ O or NiO-SiO ₂ .A1 ₂ O ₃ , WO ₂ -SiO ₂ · A1 ₂ O ₃ , NiO-WO ₂ · SiO ₂ · A1 ₂ O _3, etc. The oxidation catalyst is platinum (Pt), rhodium (Rh), ruthenium (Ru), or palladium (Pd).

As the shift catalyst, a copper-based or iron-based base metal catalyst such as a mixture of CuO—ZnO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ or copper oxide is used. However, when the reaction is carried out at 700 ° C. or higher, it is desirable to use Cr ₂ O ₃ . The mixture of the raw material gas and the water vapor is supplied to the reforming catalyst layer of the outer cylinder, then passes through the mixed catalyst layer and the shift catalyst layer, and is supplied as reformed gas to the CO reducer 7 from the pipe g. In the reformed gas, CO is reduced to the ppm order by the CO reducer 7 and supplied to the fuel cell 8.

  In the present embodiment, a humidification tank 33 is provided in the cooling water system 9 separately from the cooling water tank 10. That is, a branch control valve 32 is provided in the pipe m connecting the fuel cell 8 and the hot water storage tank 13, the pipe p is branched from the branch control valve 32, and the tip of the pipe p communicates with the cooling water tank 10, but in the middle Is provided with a humidifying tank 33. And the cooling water which flows through the piping p, and the stored water in the humidification tank 33 heat-exchange.

  City gas (13A) is used as the raw material gas for the reformer 1. 13A is desulfurized by the desulfurizer 2, and is boosted to about several hundred mmAq by a blower 12a for pressurization and supplied to the humidification tank 33 from the pipe a, where it is blown into the stored water by bubbling or the like. The water surface height in the humidification tank 33 is about 200mmAq, and the line pressure loss of the entire system is designed to be about 200mmAq or less, so the lift of the booster 12a satisfies the specifications at a low pressure of about several hundred mmAq. it can.

  The humidification tank 33 is a closed type. Here, “closed type” means a closed structure in which the saturated water vapor pressure state is maintained in the humidifying tank 33. In the embodiment, the raw material gas supply system 20 for the humidifying tank 33 is constituted by the pipe a, the pump 12a, and the blowing portion to the humidifying tank 33.

  On the other hand, the cooling water (reserved water) stored in the cooling water tank 10 is supplied to the cooling part of the fuel cell through the pipe n provided with the pump 11, and the cooling water heated by the heat exchange is supplied from the pipe m to the cooling water. Return to tank 10. The hot water storage tank 13 has a function of exchanging heat with cooling water, serving hot water such as hot water supply, and storing hot water.

  The raw material gas 13A blown into the humidifying tank 33 is humidified by the stored water in a saturated state, and a mixture of the raw material gas and water vapor having a predetermined steam / carbon molar ratio (S / C) stays in the upper space of the humidifying tank 33. . This mixture of raw material gas and water vapor is supplied to the reformer 1 as it is from the pipe e. In the embodiment, the reformer 1 is connected to the reformer 1 by the opening provided in the humidification tank 33 for taking out the mixture of the raw material gas and the water vapor staying from the upper space of the humidification tank 33 and the pipe e connected thereto. A source gas-steam mixture supply system 21 is configured. Note that an adjustment valve for adjusting the flow rate of the raw material gas can be provided in the pipe a.

  As the fuel cell 8, a PAFC (Phosphoric Acid Fuel cell) or PEFC (Polymer Electrolyte Fuel Cell) can be used. As described above, a predetermined steam / carbon is used in the cooling water tank. In order to obtain a mixture of raw material gas and water vapor with a high molar ratio (S / C), a fuel cell designed to be able to operate in a high temperature region is desirable, but such a high temperature type fuel cell has already been realized. .

  Next, the steam / carbon molar ratio (S / C) will be described. When city gas (13A) is used as the raw material gas for the reformer 1, the raw material gas 13A is mainly composed of methane, ethane, propane, and butane. The raw material gas 13A is, for example, 4.23 NL / min. When blowing into the cooling water tank at a flow rate, the number of moles of carbon (C) per hour is calculated to be about 0.0113 (kg-mol / h).

  On the other hand, the relationship between the temperature of the stored water stored in the humidification tank 33 and the saturated vapor pressure is about 567 mmHg, 611 mmHg, and 658 mmHg when the temperatures are 92 ° C., 94 ° C., and 96 ° C., respectively. The number of moles (S) of the amount of water vapor added per hour when the flow rate of the raw material gas 13A was blown into the stored water was 0.0333 kg-mol / h when the temperature was 92 ° C and 94 ° C. 0.0464 kg-mol / h at 96 ° C., and about 0.0728 kg-mol / h at 96 ° C. As a result, the steam / carbon ratio (S / C) of the mixture of the source gas and water vapor is 2.52 when the temperature is 92 ° C, 3.52 when the temperature is 94 ° C, and about 5.51 when the temperature is 96 ° C. It becomes.

  However, it is an ideal state that the saturated vapor pressure equivalent 100% is added to the raw material gas 13A, and in reality, the amount of addition is often reduced due to condensation due to heat dissipation. In such a case, if the relationship between the temperature of the humidifying tank 33 and the amount of added water vapor is experimentally acquired, and a correction corresponding to a predetermined amount of added water vapor is applied to the temperature of the humidifying tank 33, the operation will be improved. Reliability can be obtained. Normally, the mixing ratio (S / C) of the raw material gas and steam supplied to the reformer is preferably about 2.5 to 3 in consideration of the system efficiency and the reforming reaction conversion rate. I want to control the temperature of the stored water at 93 ° C ± 1 ° C.

  In the present invention, the “high-temperature fuel cell” means that at least the operating temperature is controlled to 93 ° C. or higher, so that the cooling water heat-exchanged in the cooling part of the fuel cell is also heated to 93 ° C. or higher. After the heat exchange in the hot water storage tank 13, it is returned to the cooling water tank 10. On the other hand, the humidification tank 33 is provided with a temperature detection unit 30 using, for example, a resistance thermometer or a thermocouple, and the detection signal is transmitted to the temperature controller 31. Here, the temperature controller 31 is a branch disposed in the pipe m on the battery cooling water return side so that the stored water temperature detected by the temperature detection unit 30 is maintained at a predetermined temperature, in this case, 93 ° C. By operating the control valve 32, a part of the cooling water heated to 93 ° C. or more is branched and distributed, and heat exchange with the humidifying tank 33 is performed to control the temperature.

  As a result, since the water vapor added to the raw material gas is discharged to the humidifying tank 33, the recovered water recovered from the system is supplied in order to maintain a predetermined amount of the stored water in the humidifying tank 33. Although the supplementary water pipe o with the pump 12 is arranged, since the recovered water is generally at a low temperature of about 40 to 60 ° C., the temperature of the stored water is lowered. By performing heat exchange with the high-temperature cooling water, the humidifying tank 33 is controlled to a predetermined temperature, in this case, 93 ° C., and a desirable mixing ratio of raw material gas and water vapor (S / C) = Maintenance of 2.5 to 3.0 can be realized.

  Hydrogen rich reformed gas generated by the reformer 1 is supplied to the anode side of the fuel cell 8 from the pipe h, and air is supplied to the cathode side from the pipe provided with the blower 14. Since a considerable amount of hydrogen remains in the anode exhaust gas flowing out from the pipe i, it is supplied to a heat utilization device 22 such as a fuel tank or a heating section of the device indicated by a dotted line. Conventionally, this anode exhaust gas has been supplied to the steam generator as a fuel. However, according to the present embodiment, the steam generator is not necessary, so that the anode exhaust gas can be effectively used as a heat source for other equipment.

  A part of the oxygen in the air supplied to the cathode side of the fuel cell 8 is consumed for power generation, but the cathode exhaust gas flowing out from the pipe f contains the remaining oxygen. According to the experiment, in the case of the fuel cell 8 that generates power of about 1 KW, the consumption rate or utilization rate of oxygen in the air supplied to the cathode side is about 50 to 60%. The cathode exhaust gas is discharged from the pipe f, and the oxygen concentration in the cathode exhaust gas is about 7% on average.

  Thus, if the average oxygen concentration in the cathode exhaust gas is about 7%, it can be sufficiently used as the oxidizing air of the reformer 1. Therefore, in the present embodiment, the cathode exhaust gas is supplied to the reformer 1 through the pipe f provided with the adjusting valve 15. In this embodiment, the piping f and the regulating valve 15 constitute an oxidizing air supply system 23 to the reformer 1.

  The reforming temperature of the reformer 1 is detected by a temperature detector 18 using, for example, a resistance thermometer or a thermocouple, and the detection signal is transmitted to the temperature controller 17. The temperature controller 17 controls the regulating valve 15 so that the reforming temperature detected by the temperature detector 18 can be maintained at a preset value. For example, when the detected reforming temperature is lower than a preset value, the temperature controller 17 performs control to increase the opening degree of the regulating valve 15, and conversely, the reforming temperature becomes higher than the preset value. If so, the temperature controller 17 performs control to reduce the opening of the regulating valve 15. In the present embodiment, the temperature control unit 16 includes the temperature detection unit 18 and the temperature controller 17.

  When the flow rate of the cathode exhaust gas supplied to the reformer 1 is adjusted by the reforming temperature control as described above, the piping k for supplying air to the cathode side of the fuel cell 8 and the piping e through which the cathode exhaust gas flows are connected via the cathode side. Accordingly, the flow rate of air supplied to the cathode side automatically changes following the increase and decrease of the flow rate of the cathode exhaust gas.

  However, as described above, the load variation of the fuel cell 8 and the amount of air supplied to the cathode side, the reformed gas flow rate supplied from the reformer 1 and the amount of oxidized air are proportional to each other. Based on the fluctuations, load fluctuations, reformed gas flow fluctuations, oxidation air flow (cathode exhaust gas flow) fluctuations, fluctuations in the amount of air supplied to the cathode, and so on, are balanced against each other by the temperature control. Thus, even if a certain degree of imbalance occurs in the relationship temporarily or transiently, it is well within the allowable operating range of a normal fuel cell.

  FIG. 2 is a process flow diagram showing a second embodiment of the reforming apparatus of the present invention. The difference between the present embodiment and the first embodiment of FIG. 1 is that the cooling water tank 10 provided in the cooling water system 9 is used as the cooling water tank and the humidifier 33, and the other configurations are the same. Is done. Accordingly, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, the piping m on the cooling unit outlet side of the fuel cell 8 communicates with the humidification tank 33 that also serves as a cooling water tank, and the hot water storage tank 13 includes a circulation piping q provided with a control valve 34 and a pump 35. The water flowing through the pipe q is heated by exchanging heat with the humidification tank 33 on the way. The temperature control unit 31 controls the circulation amount of the water flowing through the pipe q so that the temperature detection unit 30 detects the humidification tank 33 and the detected temperature becomes a preset temperature. Thus, in this embodiment, the temperature of the humidification tank 33 is controlled to be constant by controlling the amount of water circulation in the hot water storage tank 13, that is, the amount of heating to the hot water storage tank 13.

  The reforming system of the present invention can be used for a system that generates a hydrogen-rich reformed gas in a reformer and supplies the reformed gas to a fuel cell.

The process flow figure showing a 1st embodiment of the reforming system of the present invention. The process flow figure showing a 1st embodiment of the reforming system of the present invention. The process flow figure of the conventional reforming system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reformer 2 Desulfurizer 3 Steam generator 4 Pump 5 Blower 6 Mixer 7 CO reducer 8 Fuel cell 9 Cooling water system

DESCRIPTION OF SYMBOLS 10 Cooling water tank 11 Pump 12 Pump 12a Blower 13 Hot water storage tank 14 Blower 15 Adjustment valve 16 Temperature controller 17 Temperature controller 18 Temperature detection part

20 Source gas supply system 21 Source gas-steam mixture supply system 22 Heat utilization device 23 Oxidized air supply system a to q Pipe 30 Humidity tank temperature detection unit 31 Humidity tank temperature control unit 32 Branch control valve 33 Humidification tank 34 Control valve 35 pump

Claims (5)

In the reforming system that supplies the fuel cell 8 with the hydrogen-rich reformed gas produced by the self-oxidation internal heating type reformer 1,
A closed humidification tank 33 is provided in the cooling system 9 that circulates the fuel cell 8, a raw material gas supply system 20 that supplies a raw material gas for generating reformed gas into the water stored in the humidification tank 33, and the humidification tank 33. A reforming system comprising a source gas-steam mixture supply system 21 for supplying a mixture of a source gas and steam staying in an upper space of the reformer 1 to the reformer 1.   2. The fuel cell 8 according to claim 1, wherein the fuel cell 8 has a humidification tank 33 such that a steam / carbon molar ratio (S / C) of a mixture of raw material gas and water vapor generated in the humidification tank 33 is 2.5 to 3. A reforming system characterized by being a high-temperature fuel cell capable of maintaining the stored water temperature. In the reforming system that supplies the fuel cell 8 with the hydrogen-rich reformed gas produced by the self-oxidation internal heating type reformer 1,
A reforming system comprising an oxidizing air supply system for supplying a cathode exhaust gas of the fuel cell as oxidizing air for the reformer.   In Claim 3, the adjustment valve 15 which adjusts the flow volume of cathode exhaust gas in the said oxidation air supply system 23 is provided, and the said adjustment valve 15 is maintained so that the reforming temperature of the said reformer 1 may be maintained at the preset value. A reforming system comprising a temperature control device 16 for controlling. In the reforming system that supplies the fuel cell 8 with the hydrogen-rich reformed gas produced by the self-oxidation internal heating type reformer 1,
A closed humidification tank 33 is provided in the cooling system 9 circulating through the fuel cell 8, a raw material gas supply system 20 for supplying a raw material gas for generating reformed gas into the stored water of the humidification tank 33, and the humidification tank 33, a source gas-steam mixture supply system 21 for supplying a mixture of the source gas and steam staying in the upper space of 33 to the reformer 1,
A reforming system comprising an oxidizing air supply system for supplying a cathode exhaust gas of the fuel cell as oxidizing air for the reformer.

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