JP2013032238A - Hydrogen generator and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove efficiently sulfur compounds by heightening reactivity of a hydrodesulfurization reaction in a hydrogen generator including a hydrodesulfurizer.SOLUTION: This hydrogen generator 100 includes: a reformer 1 for generating hydrogen-containing gas by a reforming reaction by using a raw material; a hydrodesulfurizer 2 for removing sulfur compounds contained in the raw material supplied into the reformer 1; a recycle passage 7 for supplying therethrough a part of the hydrogen-containing gas to which a processing for reducing carbon monoxide in the hydrogen-containing gas is not performed, to the raw material before entering the hydrodesulfurizer 2, after passing the reformer 1; and a carbon monoxide reducer 8 provided on the recycle passage 7, for reducing carbon monoxide in the hydrogen-containing gas.

Description

  The present invention relates to a hydrogen generator that generates a hydrogen-containing gas, and a fuel cell system including the hydrogen generator.

  A fuel cell system supplies a hydrogen-containing gas and an oxygen-containing gas to a fuel cell stack (hereinafter simply referred to as a “fuel cell”) that is a main body of a power generation unit, and advances an electrochemical reaction between hydrogen and oxygen. It is a system that takes out the chemical energy generated by this as electrical energy and generates electricity. In addition, high-efficiency power generation is possible, and heat energy generated during power generation operation can be easily used, so development is being promoted as a distributed power generation system that can achieve high energy use efficiency. ing.

  In a fuel cell system, a hydrogen-containing gas is used as a fuel for power generation, but an infrastructure for supplying the hydrogen-containing gas is often not established. For this reason, the conventional fuel cell system is provided with a hydrogen generator that generates hydrogen-containing gas using fossil raw materials such as city gas mainly composed of natural gas supplied from the existing infrastructure or LPG. Has been. The hydrogen generator is a reformer that generates hydrogen-containing gas (reformed gas) by reacting the raw material with water vapor using a Ru catalyst or Ni catalyst at a temperature of, for example, 600 to 700 ° C. (reforming reaction). Equipped with a bowl.

  In order to detect the leakage of raw materials such as city gas or LPG supplied from infrastructure, dimethyl sulfide (DMS), tertiary-butylmercaptan (TBM), tetrahydrothiophene (tetrahydro thiophene) A sulfur-based odorant such as THT) is added. Moreover, the sulfur compound derived from a raw material is also contained. These sulfur-based odorants and naturally-occurring sulfur compounds (collectively referred to as “sulfur compounds”) poison the catalysts such as Ru catalyst and Ni catalyst used in the reformer and inhibit the reforming reaction. There is a risk.

  For this reason, the hydrogen generator is generally provided with a desulfurizer for removing sulfur compounds from the raw material before being introduced into the reformer. As the desulfurizer, a hydrodesulfurizer using a hydrodesulfurization method (for example, Patent Document 1 and Patent Document 2) can be used. In the hydrodesulfurization method, a hydrogenation reaction is performed by hydrogenating (hydrogenating) a sulfur compound at a high temperature using a hydrogenation catalyst to form hydrogen sulfide, and a desulfurization reaction in which the hydrogen sulfide is removed by a chemical reaction. These reactions are collectively called hydrodesulfurization reaction. Since the hydrodesulfurization method uses a chemical reaction, for example, the desulfurization capacity can be increased and the size of the desulfurizer can be reduced as compared with the adsorption desulfurization method using an adsorbent.

JP 7-320761 A JP-A-11-139803

  The hydrogen generator described in Patent Document 1 and Patent Document 2 includes a transformer that reduces carbon monoxide in the hydrogen-containing gas generated in the reformer. And most of the hydrogen-containing gas that has passed through this transformer is supplied to the fuel cell, and the remaining part is supplied to the hydrodesulfurizer.

  However, until now, in a hydrogen generator configured to supply carbon utilization equipment (for example, a fuel cell) without reducing carbon monoxide in a hydrogen-containing gas using a transformer or the like, to a hydrodesulfurizer The appropriate hydrogen-containing gas supply configuration has not been studied.

  The present invention has been made in view of the above circumstances, and is suitable for a hydrodesulfurizer in a hydrogen generator configured to supply carbon utilization equipment without reducing carbon monoxide in a hydrogen-containing gas. It aims at supplying the hydrogen generator which supplies hydrogen containing gas, and a fuel cell system.

  As a result of intensive studies on the above problems, the inventors of the present application have noticed the following points.

  When a part of the hydrogen-containing gas generated by the reformer is supplied to the hydrodesulfurizer, the sulfur concentration in the raw material gas after passing through the hydrodesulfurizer becomes higher than that of the conventional hydrogen generator. Here, the inventor of the present application speculates that carbon monoxide contained in the hydrogen-containing gas causes a side reaction such as a methanation reaction in the hydrodesulfurizer, thereby reducing the hydrodesulfurization reaction amount. Then, the following invention has been conceived.

  That is, the hydrogen generator of the present invention includes a reformer that generates a hydrogen-containing gas by a reforming reaction using a raw material, and a hydrodesulfurizer that removes a sulfur compound contained in the raw material supplied to the reformer. And, after passing through the reformer, a part of the hydrogen-containing gas that has not been treated to reduce carbon monoxide in the hydrogen-containing gas is supplied to the raw material before flowing into the hydrodesulfurizer A flow path and a carbon monoxide reducer provided in the recycle flow path for reducing carbon monoxide in the hydrogen-containing gas.

  In a preferred embodiment, the carbon monoxide reducer includes a shift catalyst used for a shift reaction between carbon monoxide and water vapor.

  In a preferred embodiment, the carbon monoxide reducer includes an oxidizing gas supply device that supplies an oxidizing gas to a hydrogen-containing gas that flows through a recycle flow path upstream of the carbon monoxide reducer, and the carbon monoxide reducer includes carbon monoxide and an oxidation gas. An oxidation catalyst used for the oxidation reaction with gas is provided.

  In a preferred embodiment, the carbon monoxide reducer includes a methanation catalyst used for a carbon monoxide methanation reaction.

  In a preferred embodiment, the hydrogen generator includes an adsorptive desulfurizer that physically adsorbs sulfur compounds in the raw material in the raw material supply path, and a raw material supplied to the reformer via the adsorptive desulfurizer. A first flow path, a second flow path through which the raw material bypasses the adsorption desulfurizer and is supplied to the reformer via the hydrodesulfurizer, the first flow path, and the first flow path And a controller for switching the switch to the first flow path side during at least a part of the start-up period.

  In a preferred embodiment, the controller switches the switch to the first flow path side when the temperature of the hydrodesulfurizer is lower than a usable temperature.

  The fuel cell system of the present invention includes the above hydrogen generator and a fuel cell that generates electric power using a hydrogen-containing gas supplied from the hydrogen generator.

  In a preferred embodiment, the fuel cell is a solid oxide fuel cell.

  Since the hydrogen-containing gas with reduced carbon monoxide is supplied to the hydrodesulfurizer, a decrease in the desulfurization performance of the hydrodesulfurizer can be suppressed.

1 is a schematic diagram of a hydrogen generator of Embodiment 1. FIG. FIG. 5 is a schematic diagram showing a modification of the hydrogen generator of Embodiment 1. 3 is a schematic diagram of a hydrogen generator according to Embodiment 2. FIG. 6 is a schematic diagram of a fuel cell system according to Embodiment 3. FIG. FIG. 9 is a schematic diagram showing a modification of the fuel cell system according to Embodiment 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram showing the configuration of a hydrogen generator 100 according to Embodiment 1 of the present invention.

  The hydrogen generator 100 includes a reformer 1, a hydrodesulfurizer 2, a raw material supplier 3 and a raw material supply passage 5 that supply a raw material gas to the reformer 1, a hydrogen-containing gas passage 6, a recycle flow A path 7 and a carbon monoxide reducer 8 are provided.

  The reformer 1 generates a hydrogen-containing gas using a raw material gas. Specifically, in the reformer 1, the raw material gas undergoes a reforming reaction to generate a hydrogen-containing gas. The reforming reaction may take any form, and examples thereof include a steam reforming reaction, an autothermal reaction, and a partial oxidation reaction. Although not shown in FIG. 1, equipment required for each reforming reaction is provided as appropriate. For example, if the reforming reaction is a steam reforming reaction, a combustor that heats the reformer 1, an evaporator that generates steam, and a water supplier that supplies water to the evaporator are provided. The fuel for the combustor may be any fuel. For example, a raw material such as natural gas or LPG may be used, or a hydrogen-containing gas discharged from the reformer 1 may be used. Further, the remaining hydrogen-containing gas (off-gas) that has not been consumed at the supply destination (hydrogen-using device) of the hydrogen-containing gas may be used. In addition, the reformer 1 may be provided with a reforming temperature detector that detects the temperature of the reaction that generates the hydrogen-containing gas. If the reforming reaction is an autothermal reaction, the hydrogen generator 100 is further provided with an air supply device (not shown) for supplying air to the reformer 1. The source gas is a gas containing an organic compound composed of at least carbon and hydrogen, such as city gas mainly composed of methane, natural gas, and LPG.

  The raw material supply path 5 is a flow path through which the raw material gas supplied to the reformer 1 flows.

  The hydrodesulfurizer 2 removes sulfur compounds in the raw material gas supplied to the reformer 1. The hydrodesulfurizer 2 is configured by filling a vessel with a desulfurization agent for hydrodesulfurization. The desulfurization agent for hydrodesulfurization is, for example, a CoMo-based catalyst that converts a sulfur compound in a raw material gas into hydrogen sulfide, and a ZnO-based catalyst that is a sulfur adsorbent that is provided downstream thereof to adsorb and remove hydrogen sulfide, or It is comprised with a CuZn-type catalyst. The desulfurization agent for hydrodesulfurization is not limited to this example, and may be composed of only a CuZn-based catalyst having both a function of converting a sulfur compound into hydrogen sulfide and a function of adsorbing hydrogen sulfide.

  The raw material supplier 3 is a device that adjusts the flow rate of the raw material gas supplied to the reformer 1, and is constituted by, for example, a booster and a flow rate adjustment valve, but may be constituted by any one of these. For example, a constant displacement pump is used as the booster, but is not limited thereto.

  The source gas is supplied from a source gas supply source. The source gas supply source has a predetermined supply pressure, and examples thereof include a source gas cylinder and a source gas infrastructure.

  A pressure detector (not shown) for detecting the pressure in the raw material supply path 5 upstream from the junction with the recycle flow path 7 may be provided.

  The hydrogen-containing gas channel 6 is a channel through which the hydrogen-containing gas generated by the reformer 1 flows.

  The recycle channel 7 sends a part of the hydrogen-containing gas sent from the reformer 1 and not subjected to the treatment for reducing carbon monoxide to the raw material in the raw material supply channel 5 upstream from the hydrodesulfurizer 2. It is a flow path for supplying gas. The upstream end of the recycle channel 7 may be connected to any location as long as the hydrogen-containing gas channel 6 through which the hydrogen-containing gas sent from the reformer 1 flows.

  The carbon monoxide reducer 8 is provided in the recycle flow path 7 from the hydrogen-containing gas flow path 6 to the raw material supply path 5 and reduces carbon monoxide in the hydrogen-containing gas. The carbon monoxide reducer 8 includes, for example, a Cu—Zn-based shift catalyst.

  Although not shown, a flow rate controller may be provided in the recycle channel 7. The flow rate controller adjusts the flow rate of the hydrogen-containing gas flowing through the recycle channel 7. The flow controller may have any configuration as long as the flow path of the hydrogen-containing gas can be adjusted. For example, a flow control valve or the like is used. Moreover, you may have a controller (not shown) which controls a flow controller. The controller only needs to have a control function, and includes an arithmetic processing unit and a storage unit that stores a control program. Examples of the arithmetic processing unit include an MPU and a CPU. An example of the storage unit is a memory. The controller may be composed of a single controller that performs centralized control, or may be composed of a plurality of controllers that perform distributed control in cooperation with each other.

  Next, operation | movement of the hydrogen generator 100 of this embodiment is demonstrated. Here, a case where the reformer 1 generates a hydrogen-containing gas by a steam reforming reaction will be described as an example, but the reforming reaction is not limited to the steam reforming reaction.

  The raw material is supplied from the raw material supply path 5 to the reformer 1 through the hydrodesulfurizer 2. The raw material is city gas mainly composed of natural gas supplied from the infrastructure, for example. In the reformer 1, a hydrogen-containing gas is generated by a reforming reaction of the raw material. Here, since the steam reforming reaction is performed, the raw material is supplied to the reformer 1 and water used for the steam reforming reaction is supplied from a water supply channel (not shown). The amount of water supplied is, for example, 2.5 to 3 times the number of carbons in the raw material. Combustion is started in a combustor (not shown) of the reformer 1 to increase the temperature in the reformer 1. Thereby, the steam reforming reaction of a raw material can be advanced in the reformer 1, and a hydrogen containing gas can be produced | generated.

  The hydrogen-containing gas generated in the reformer 1 is supplied to the outside through the hydrogen-containing gas flow path 6. At this time, a raw material is supplied as fuel from a fuel supply path (not shown) to the combustor, and combustion air is supplied from a combustion air supply path (not shown), thereby causing combustion in the combustor to proceed. .

  In the present embodiment, a part of the hydrogen-containing gas (carbon monoxide concentration: for example, 10% or more) generated in the reformer 1 is used as a guide, for example, in an amount of 1-2% of the supply amount of the raw material. Introduce into the recycling flow path 7. The hydrogen-containing gas introduced into the recycle channel 7 passes through the carbon monoxide reducer 8 and is added to the raw material before flowing into the hydrodesulfurizer 2. By passing through the carbon monoxide reducer 8, the concentration of carbon monoxide in the hydrogen-containing gas is reduced to, for example, 0.5% or less.

  In addition, when using a shift catalyst with the carbon monoxide reducer 8, in order to exhibit the shift reactivity of the shift catalyst, the carbon monoxide reducer 8 is operated at a temperature of 200 to 250 ° C., for example. Moreover, the hydrodesulfurizer 2 is operated at a temperature of 250 to 300 ° C., for example. The heat source required for heating the hydrodesulfurizer 2 is not particularly limited. The hydrodesulfurizer 2 may be heated by installing the hydrodesulfurizer 2 in the vicinity of the reformer 1 operating at a high temperature.

  The hydrogen generator 100 according to this embodiment has the following advantages.

  Conventionally, when a hydrogen-containing gas having a high carbon monoxide concentration after the reforming reaction is directly used in the hydrodesulfurization reaction, the hydrodesulfurization reactivity is lowered in the hydrodesulfurizer 2, and the sulfur compound in the raw material is reduced to a predetermined level. There was a possibility that the concentration could not be reduced. In contrast, in this embodiment, the hydrogen-containing gas generated by the reforming reaction is added to the raw material after passing through the carbon monoxide reducer 8. The raw material to which the hydrogen-containing gas is added is supplied to the hydrodesulfurizer 2. Therefore, since the hydrogen-containing gas with reduced carbon monoxide is supplied to the hydrodesulfurizer 2 and can be used for the hydrodesulfurization reaction, the reactivity of the hydrodesulfurization reaction can be maintained.

  In addition, by installing the carbon monoxide reducer 8 in the recycle channel 7, the carbon monoxide reducer 8 can be made smaller than when installed in the raw material supply channel 5 and the hydrogen-containing gas channel 6. . The amount of hydrogen necessary for the hydrogenation reaction depends on the amount of sulfur compound in the raw material, but if the amount of sulfur compound in the raw material is several tens of ppm, it becomes 1 to 2% of the supply amount of the raw material. That is, in order to reduce carbon monoxide in the hydrogen-containing gas in the recycle channel 7, the amount of the shift catalyst provided in the carbon monoxide reducer 8 may be an amount corresponding to the amount of hydrogen-containing gas to be recycled. For example, in order to reduce carbon monoxide in the hydrogen-containing gas after being generated by the reforming reaction and before being supplied to the recycle channel 7, a transformer is installed downstream of the reformer 1. In comparison, the amount of the shift catalyst can be reduced to several tenths. Therefore, simplification, size reduction, cost reduction, etc. of the hydrogen generator can be realized.

  The configuration of the hydrogen generator of this embodiment is not limited to the above configuration. Hereinafter, modified examples 1 and 2 of the hydrogen generator will be described.

  In the first modification, a Ru-based methanation catalyst is used in the carbon monoxide reducer 8 instead of the shift catalyst. In that case, the carbon monoxide reducer 8 is operated at a temperature of, for example, 200 to 250 ° C. to methanate the carbon monoxide in the hydrogen-containing gas, thereby reducing the carbon monoxide in the hydrogen-containing gas. The configuration of the hydrogen generator of Modification 1 is the same as the configuration of the hydrogen generator 100 shown in FIG.

  In the modified example 2, in the carbon monoxide reducer 8, for example, a Ru-based selective oxidation catalyst is used instead of the shift catalyst.

  FIG. 2 is a schematic diagram illustrating a second modification of the hydrogen generator 100 according to the present embodiment. As illustrated, in the second modification, an oxidizing gas supply device 10 is provided in the recycling flow path 7 upstream of the carbon monoxide reducer 8. The oxidizing gas supply device 10 supplies the oxidizing gas to the hydrogen-containing gas that flows through the recycle channel 7 upstream of the carbon monoxide reducer 8. The carbon monoxide reducer 8 is operated at a temperature of, for example, 100 to 200 ° C., and the carbon monoxide in the hydrogen-containing gas is oxidized by oxygen in the air supplied from the oxidizing gas supplier 10, thereby containing hydrogen. Reduce carbon monoxide in the gas.

  In either modification, since the hydrogen-containing gas after the reduction of carbon monoxide is caused to flow into the hydrodesulfurizer 2, a decrease in the reactivity of the hydrodesulfurization reaction due to carbon monoxide can be suppressed. Further, the amount of catalyst to be used can be reduced as compared with the configuration in which carbon monoxide in the hydrogen-containing gas is reduced before being supplied to the recycle channel 7. Therefore, simplification, size reduction, cost reduction, etc. of the hydrogen generator can be realized.

  Further, in order to keep the temperature of the carbon monoxide reducer 8 at an operating temperature corresponding to the catalyst used for the carbon monoxide reducer 8, the carbon monoxide reducer 8 and the recycle flow path 7 are provided with a configuration such as heat insulation. Is desirable.

(Embodiment 2)
FIG. 3 is a schematic diagram showing the configuration of the hydrogen generator 100 according to Embodiment 2 of the present invention. Constituent elements similar to those of the hydrogen generator 100 according to Embodiment 1 shown in FIG. Only the differences from the first embodiment will be described below.

  The hydrogen generation apparatus 100 of the present embodiment includes an adsorption desulfurizer 11, a first channel through which raw material passes through the adsorption desulfurizer 11, a second channel through which raw material bypasses the adsorptive desulfurizer 11, and a first channel. The second embodiment is different from the first embodiment in that it includes a switch that switches between the first flow path and the second flow path, and a controller 20 that controls the switch. In the illustrated example, a branch path 15 is provided in the raw material supply path 5 upstream of the hydrodesulfurizer 2, and the adsorptive desulfurizer 11 is provided in the branch path 15.

  The adsorptive desulfurizer 11 has, for example, a zeolite-based adsorptive desulfurization agent, and physically adsorbs sulfur compounds in the raw material.

  The first channel is a channel through which the raw material is supplied to the reformer 1 via the adsorptive desulfurizer 11. Here, the branch path 15 and the raw material supply path 5 downstream of the branch path 15 correspond to the first flow path. The second flow path is a flow path in which the raw material bypasses the adsorptive desulfurizer 11 and is supplied to the reformer 1 via the hydrodesulfurizer 2. Here, the raw material supply path 5 corresponds to a second flow path.

  The raw material supply path 5 is provided with a first valve 12, and the branch path 15 is provided with a second valve 13. A third valve 14 is provided in the recycle channel 7. Here, the said valves 12 and 13 function as a switch which switches a 1st flow path and a 2nd flow path. The controller 20 switches the switch to the first flow path side in at least a part of the period when the hydrogen generator 100 is activated. For example, when the temperature of the hydrodesulfurizer 2 is lower than the usable temperature, the switch may be switched to the first flow path side.

  Although not shown, the temperature of the hydrodesulfurizer 2 is detected using at least one of a detector that directly detects the temperature of the hydrodesulfurizer 2 and a detector that indirectly detects the temperature. As a detector for direct detection, a temperature detector 16 provided in the hydrodesulfurizer 2 is exemplified. As a detector for detecting indirectly, a detector for detecting a physical quantity that changes in correlation with the temperature of the hydrodesulfurizer 2, for example, a time after starting (or heating the hydrodesulfurizer 2) The timer (not shown) which measures this is illustrated. In the case where the hydrodesulfurizer 2 is heated by exchanging heat with the reformer 1, a temperature detector (not shown) for detecting the temperature of the reformer 1 is exemplified.

  The operation of the hydrogen generator 100 of this embodiment will be described more specifically. The description of the same operation as that of the hydrogen generator 100 of Embodiment 1 shown in FIG. 1 is omitted.

  In the present embodiment, the raw material that has passed through the adsorptive desulfurizer 11 is supplied to the hydrodesulfurizer 2 for at least a part of the period when the hydrogen generator 100 is activated. Such an operation provides the following advantages.

  In order to effectively advance the hydrogenation reaction in the hydrodesulfurizer 2, it is preferable to operate the hydrodesulfurizer 2 at a temperature of 250 to 300 ° C. However, when the hydrogen generator 100 is activated (hereinafter abbreviated as “apparatus activation”), it is difficult to obtain heat necessary for the hydrogenation reaction, and sufficient desulfurization performance cannot be obtained in the hydrodesulfurizer 2. there is a possibility. Therefore, in this embodiment, the switch is switched to the first flow path side so that the raw material passes through the adsorptive desulfurizer 11 when the apparatus is activated. Specifically, the first valve 12 is closed and the second valve 13 is opened. Thereby, since the sulfur compound in the raw material can be reduced by the adsorption desulfurizer 11, poisoning of the reforming catalyst by the sulfur compound can be prevented even when the apparatus is activated. Further, the third valve 14 is closed when the adsorptive desulfurizer 11 is used.

  Note that the first flow path may be configured to supply the raw material directly to the reformer 1 without passing through the hydrodesulfurizer 2 after passing through the adsorption desulfurizer 11. For example, the upstream end of the branch path 15 is disposed in the raw material supply path 5 upstream of the hydrodesulfurizer 2, and the downstream end of the branch path 15 is disposed in the raw material supply path 5 downstream of the hydrodesulfurizer 2. Also good. In this case, it is possible to switch to the first flow path side by closing the first valve 12 and opening the second valve 13. Even in this case, the third valve 14 is closed when the adsorptive desulfurizer 11 is used.

  When it is detected that the temperature of the hydrodesulfurizer 2 has reached a temperature suitable for the progress of the hydrogenation reaction, the switching unit is configured so that the raw material is supplied to the hydrodesulfurizer 2 without passing through the adsorption desulfurizer 11. Is switched to the second flow path side. For example, when the temperature detector 16 detects that the temperature in the hydrodesulfurizer 2 exceeds a preset hydrodesulfurization temperature (for example, 250 ° C.), the first valve 12 and the third valve 14 are opened, The second valve 13 is closed.

  Thus, according to the present embodiment, at the time of start-up of the device where the temperature of the hydrodesulfurizer 2 is low, sufficient adsorption performance can be secured by the adsorption desulfurizer 11, and the temperature of the hydrodesulfurizer 2 is higher than a predetermined temperature. When it becomes higher, it is possible to perform an operation utilizing the desulfurization performance of the hydrodesulfurizer 2. Further, the adsorptive desulfurizer 11 is used only for a necessary period, and is not used after the temperature of the hydrodesulfurizer 2 becomes high. Thereby, it can suppress that the lifetime of the adsorption agent provided in the adsorption desulfurizer 11 falls.

(Embodiment 3)
The third embodiment according to the present invention is a fuel cell system provided with the hydrogen generator 100 described above.

  FIG. 4 is a schematic diagram of a fuel cell system 200 according to Embodiment 3 of the present invention.

  The fuel cell system 200 includes a fuel cell 30 and a hydrogen generator 100 that supplies a hydrogen-containing gas to the fuel cell 30 through the hydrogen-containing gas flow path 6.

  The fuel cell 30 may be any type of fuel cell. In this example, a solid oxide fuel cell (SOFC) is used. The solid oxide fuel cell performs a power generation operation using separately supplied oxidizing gas such as air and hydrogen-containing gas supplied from the hydrogen generator 100 as fuel. Further, although not shown, a cooling configuration for recovering heat generated simultaneously with power generation may be provided. The configuration and operation of the fuel cell 30 may be the same as the configuration and operation of a known general solid oxide fuel cell, and detailed description thereof is omitted.

  In the present embodiment, any one of the hydrogen generation apparatuses 100 described in the first and second embodiments can be used. That is, the hydrogen-containing gas generated in the reformer 1 is used in the fuel cell 30 without being subjected to a process for reducing carbon monoxide. On the other hand, a part of the hydrogen-containing gas generated in the reformer 1 is sent to the hydrodesulfurizer 2 after being subjected to a process for reducing carbon monoxide in the carbon monoxide reducer 8. For this reason, the hydrodesulfurization reaction can be efficiently advanced in the hydrodesulfurizer 2. Moreover, since the carbon monoxide reducer 8 is provided in the recycle flow path 7, it is only necessary to have an amount of catalyst corresponding to the amount of hydrogen-containing gas necessary for the hydrogenation reaction. Therefore, the carbon monoxide reducer 8 can be reduced in size.

  Note that the fuel cell system of this embodiment may use the off-gas of the fuel cell 30 as the recycle gas.

  FIG. 5 is a diagram showing a third modification of the fuel cell system 200 of the present embodiment. In the third modification, the off-gas of the fuel cell 30 is supplied to the hydrodesulfurizer 2 through the recycle channel 7. In the following description, description of the same configuration and operation as the fuel cell system 200 shown in FIG. 4 is omitted.

  In Modification 3, the hydrogen-containing gas generated by the reformer 1 is supplied to the anode of the fuel cell 30 through the hydrogen-containing gas flow path 6 and used for power generation. A gas containing hydrogen that has not been used for power generation among the hydrogen-containing gas is discharged from the anode as an anode off-gas (off-gas). The off-gas is sent to the carbon monoxide reducer 8 through the recycle channel 7. The off-gas after carbon monoxide is reduced by the carbon monoxide reducer 8 is supplied to the hydrodesulfurizer 2 through the raw material supply path 5.

  Also in Modification 3, the same effect as that of the fuel cell system 200 shown in FIG. 4 can be obtained. That is, since the off-gas (hydrogen-containing gas) in which carbon monoxide is reduced by the carbon monoxide reducer 8 is used in the hydrodesulfurizer 2, the hydrodesulfurization reaction can be efficiently advanced in the hydrodesulfurizer 2. . Further, since the carbon monoxide reducer 8 is provided in the recycle flow path 7, the carbon monoxide reducer 8 can be reduced in size.

  As a further modification, a recycle flow path is provided so that both the hydrogen-containing gas generated in the reformer 1 and sent to the fuel cell 30 and the off-gas of the fuel cell 30 can be supplied to the hydrodesulfurizer 2. 7 may be configured. In this case, the recycle flow path 7 may be configured to be switchable so that either the hydrogen-containing gas before being sent to the fuel cell 30 or the off-gas of the fuel cell 30 is sent to the hydrodesulfurizer 2. .

  The present invention can be applied to a hydrogen generator using a raw material containing a sulfur compound and including a hydrodesulfurizer, and a fuel cell system including such a hydrogen generator.

DESCRIPTION OF SYMBOLS 1 Reformer 2 Hydrodesulfurization device 3 Raw material supply device 5 Raw material supply channel 6 Hydrogen containing gas flow channel 7 Recycle flow channel 8 Carbon monoxide reducer 11 Adsorption desulfurizer 12 First valve 13 Second valve 14 Third valve 15 Branch path 16 Temperature detector 20 Controller 30 Fuel cell 100 Hydrogen generator 200 Fuel cell system

Claims (8)

A reformer that generates a hydrogen-containing gas by a reforming reaction using raw materials;
A hydrodesulfurizer for removing sulfur compounds contained in the raw material supplied to the reformer;
A recycling flow path for supplying a part of the hydrogen-containing gas that has not been treated to reduce carbon monoxide in the hydrogen-containing gas to the raw material before flowing into the hydrodesulfurizer after passing through the reformer When,
A hydrogen generation apparatus comprising: a carbon monoxide reducer that is provided in the recycling flow path and reduces carbon monoxide in a hydrogen-containing gas.   The hydrogen generator according to claim 1, wherein the carbon monoxide reducer includes a shift catalyst used for shift reaction of carbon monoxide and water vapor. An oxidant gas supply device for supplying an oxidant gas to the hydrogen-containing gas flowing through the recycle flow path upstream of the carbon monoxide reducer;
The hydrogen generator according to claim 1, wherein the carbon monoxide reducer includes an oxidation catalyst used for an oxidation reaction between carbon monoxide and an oxidizing gas.   The said carbon monoxide reducer is a hydrogen generator of Claim 1 provided with the methanation catalyst used for the methanation reaction of carbon monoxide. An adsorption desulfurizer that physically adsorbs sulfur compounds in the raw material to the raw material supply path;
A first flow path through which the raw material is supplied to the reformer via the adsorptive desulfurizer;
A second flow path in which the raw material bypasses the adsorptive desulfurizer and is supplied to the reformer via the hydrodesulfurizer;
A switch for switching between the first flow path and the second flow path;
The hydrogen generator according to any one of claims 1 to 4, further comprising a controller that switches the switch to the first flow path side during at least a part of the period of startup.   The hydrogen generator according to claim 5, wherein the controller switches the switch to the first flow path side when the temperature of the hydrodesulfurizer is lower than a usable temperature.   A fuel cell system comprising: the hydrogen generator according to any one of claims 1 to 6; and a fuel cell that generates electric power using a hydrogen-containing gas supplied from the hydrogen generator.   The fuel cell system according to claim 7, wherein the fuel cell is a solid oxide fuel cell.

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