JP2014101264A - Operation method of hydrogen generator, and operation method of fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation method of a hydrogen generator and an operation method of a fuel cell system that can suppress oxidation degradation of a hydrodesulfurization catalyst compared with methods in the past.SOLUTION: An operation method of a hydrogen generator includes a step S1 for adding hydrogen to a raw material so that a mole ratio of the hydrogen to oxygen in the raw material is larger than 2, a step S2 for supplying the raw material added with the hydrogen to a hydrogenation desulfurizer holding an oxidation degradable catalyst to remove sulfur compounds in the raw material, and a step S3 for generating a hydrogen-containing gas from the raw material having passed through the hydrogenation desulfurizer 2 in a reformer.

Description

  The present invention relates to a method for operating a hydrogen generator and a method for operating a fuel cell system.

  Development of a fuel cell capable of high-efficiency power generation even with a small device is being developed as a power generator for a distributed energy supply source. Hydrogen gas used as fuel for power generation by fuel cells has not been developed as a general infrastructure. Therefore, when used as a distributed apparatus, for example, a structure in which a hydrogen generator including a reformer that generates a hydrogen-containing gas by reforming a raw material such as city gas or LPG is often used.

  Odorants such as mercaptans, sulfides, or thiophenes are added to raw materials such as city gas and LPG supplied to the hydrogen generator. Since the reforming catalyst provided in the reformer is poisoned by these sulfur compounds and the performance deteriorates, it is necessary to remove the sulfur compounds in advance. As a method for this, hydrodesulfurization in which a sulfur component is desulfurized using a hydrogen-containing gas generated in a reformer has been proposed (see, for example, Patent Documents 1-3).

  Specific examples of the hydrodesulfurization catalyst include a CoMo-based catalyst or a combination of a NiMo-based catalyst and a ZnO-based or CuZn-based catalyst (for example, see Patent Document 2), or a structure that uses a CuZn-based catalyst alone (for example, see Patent Document 3). ) Etc. have been proposed.

JP 2007-55868 A Japanese Patent No. 4832614 Japanese Patent No. 3050850

  By the way, the raw material supplied to the reformer may contain oxygen (for example, peak shaving).

  For this reason, when a catalyst that undergoes oxidative degradation is used as a hydrodesulfurization catalyst, there is a risk that the hydrodesulfurization catalyst will undergo oxidative degradation if oxygen is contained in the raw material. Has not been studied.

  This invention is made | formed in view of such a situation, and provides the operating method of the hydrogen generator which can suppress the oxidative degradation of a hydrodesulfurization catalyst compared with the past, and the operating method of a fuel cell system. Objective.

  In order to solve the above problems, an aspect of the operation method of the hydrogen generator of the present invention includes a step of adding hydrogen to the raw material so that the molar ratio of hydrogen to oxygen in the raw material is greater than 2, and hydrogen is added. The raw material is supplied to a hydrodesulfurizer equipped with a catalyst that deteriorates by oxidation, and a sulfur compound in the raw material is removed, and a hydrogen-containing gas is generated in the reformer using the raw material that has passed through the hydrodesulfurizer. And providing a step.

  Moreover, one mode of the operation method of the fuel cell system of the present invention includes a step in which the fuel cell generates power using a hydrogen-containing gas supplied from a hydrogen generator that performs the above operation method.

  According to the aspect of the operation method of the hydrogen generator and the operation method of the fuel cell system of the present invention, there is an effect that the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the conventional method.

FIG. 1 is a block diagram illustrating an example of the hydrogen generation apparatus according to the first embodiment. FIG. 2 is a flowchart showing an example of the operation of the hydrogen generator of Embodiment 1. FIG. 3 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 1 according to the first embodiment. FIG. 4 is a block diagram illustrating an example of the hydrogen generator of Example 2 according to the first embodiment. FIG. 5 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 2 according to the first embodiment. FIG. 6 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 3 according to the first embodiment. FIG. 7 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 4 according to the first embodiment. FIG. 8 is a block diagram illustrating an example of the hydrogen generator of Example 5 according to the first embodiment. FIG. 9 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 5 according to the first embodiment. FIG. 10 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 6 according to the first embodiment. FIG. 11 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 7 according to the first embodiment. FIG. 12 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 8 according to the first embodiment. FIG. 13 is a block diagram illustrating an example of the fuel cell system according to the second embodiment. FIG. 14 is a flowchart showing an example of the operation of the fuel cell system of the second embodiment. FIG. 15 is a flowchart illustrating an example of the operation of the fuel cell system according to the third embodiment.

  Hereinafter, embodiments and examples will be described with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and the description thereof may be omitted.

(Embodiment 1)
The operation method of the hydrogen generator of Embodiment 1 includes a step of adding hydrogen to the raw material so that the molar ratio of hydrogen to oxygen in the raw material is greater than 2, and a catalyst that oxidizes and degrades the raw material to which hydrogen has been added. And a step of removing sulfur compounds in the raw material, and a step of generating a hydrogen-containing gas in the reformer using the raw material that has passed through the hydrodesulfurizer.

  Thereby, compared with the past, the oxidative degradation of a hydrodesulfurization catalyst can be suppressed.

[Device configuration]
FIG. 1 is a block diagram illustrating an example of the hydrogen generation apparatus according to the first embodiment.

  As shown in FIG. 1, the hydrogen generator 100 includes a reformer 1, a hydrodesulfurizer 2, and a controller 200.

  The reformer 1 produces | generates hydrogen containing gas using a raw material. Specifically, in the reformer 1, the raw material 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. If the reforming reaction is an autothermal reaction, the hydrogen generator 100 is further provided with an air supply device that supplies air to the reformer 1. The raw material includes an organic compound composed of at least carbon and hydrogen, such as city gas containing methane as a main component, natural gas, and LPG.

  Further, the reformer 1 may be provided with a CO reducer for reducing carbon monoxide in the hydrogen-containing gas generated by the reformer 1 downstream of the reformer 1. The CO reducer includes at least one of a transformer that reduces carbon monoxide by a shift reaction and a CO remover that reduces carbon monoxide by at least one of an oxidation reaction and a methanation reaction.

  The hydrodesulfurizer 2 includes a catalyst that deteriorates by oxidation, and removes sulfur compounds in the raw material. In the hydrodesulfurizer 2, a container is filled with a hydrodesulfurizing agent. As shown in FIG. 1, hydrogen for hydrogenation reaction is supplied to the hydrodesulfurizer 2. Thereby, hydrogen sulfide is adsorbed after the sulfur compound is converted into hydrogen sulfide using a hydrodesulfurization agent. Examples of the hydrodesulfurization catalyst that causes oxidative degradation include a hydrodesulfurization catalyst containing Cu, specifically, a CuZn-based catalyst, a catalyst that combines a CuZn-based catalyst and a CoMo-based catalyst, and the like. Examples of the hydrodesulfurization catalyst that causes oxidative degradation include hydrodesulfurization catalysts containing noble metals, specifically, catalysts containing Pt, Pd, Rh, Ru, etc. in zeolite. In addition, as a hydrodesulfurization catalyst in which oxidative deterioration occurs, a Ni—Zn-based catalyst can also be mentioned.

  The controller 200 controls the operation of the hydrogen generator 100. The controller 200 only needs to have a control function, and includes an arithmetic processing unit (not shown) and a storage unit (not shown) 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 200 may be configured by a single controller that performs centralized control, or may be configured by a plurality of controllers that perform distributed control in cooperation with each other.

[Operation]
FIG. 2 is a flowchart showing an example of the operation of the hydrogen generator of Embodiment 1.

  First, as shown in FIG. 2, during the operation of the hydrogen generator 100, hydrogen is added to the raw material so that the molar ratio of hydrogen to oxygen in the raw material is greater than 2 (step S1).

  Next, the raw material to which hydrogen has been added is supplied to the hydrodesulfurizer 2 equipped with a catalyst that undergoes oxidative degradation to remove sulfur compounds in the raw material (step S2).

  Next, a hydrogen-containing gas is generated in the reformer 1 using the raw material that has passed through the hydrodesulfurizer 2 (step S3).

Note that in step S1, the oxygen concentration contained in the raw material is obtained in advance through experiments or the like, and the supply amount of the raw material to the hydrodesulfurizer 2 so that the molar ratio of hydrogen to oxygen in the raw material is greater than 2. The amount of hydrogen to be added is also preset. Specifically, an amount of hydrogen that is equal to or higher than a predetermined volume ratio with respect to the amount of raw material supplied to the hydrodesulfurizer 2 is supplied. Here, the predetermined volume ratio is set as a value at which the molar ratio of hydrogen to oxygen in the raw material (hereinafter, H ₂ / O ₂ ) is greater than 2. In addition, as above-mentioned, the oxygen concentration in a raw material is not grasped | ascertained beforehand, and may be detected with a detector. The detector may detect the oxygen concentration in the raw material directly or indirectly.

  Examples of the detector that directly detects the oxygen concentration in the raw material include a receiver that receives oxygen concentration information transmitted from a storage device (for example, a server) outside the hydrogen generator. Another example is a detector that detects the oxygen concentration in the raw material.

  Examples of the detector that indirectly detects the oxygen concentration in the raw material include a mode in which the oxygen concentration is indirectly detected by at least one of the temperature of the hydrodesulfurizer 2 and the temperature of the reformer 1. However, the present invention is not limited to this.

  Note that the presence of oxygen in the raw material may be detected by the above-mentioned detector, or information indicating that the raw material contains oxygen is received from an external storage device (for example, a server). May be detected by a receiver. Examples of information indicating that the raw material contains oxygen include information indicating that peak shaving is being performed.

According to the operation method of the hydrogen generator 100, when the raw material contains oxygen during the operation of the hydrogen generator 100, the amount of hydrogen required to consume oxygen by the hydrogen oxidation reaction (H ₂ / O ₂ = 2) more hydrogen is supplied. Therefore, in the operation method of the hydrogen generator 100, the oxidative degradation of the hydrodesulfurization catalyst is reduced as compared with the operation method of the conventional hydrogen generator in which hydrogen is added to the raw material without considering oxygen contained in the raw material. Can be suppressed.

  Hereinafter, with reference to the drawings, specific examples of various operations of the hydrogen generator 100 controlled in accordance with the operation status of the hydrogen generator 100 when the oxygen concentration in the raw material increases during the operation of the hydrogen generator 100 will be described. I will explain.

Example 1
The operation method of the hydrogen generator of Example 1 in Embodiment 1 is the same as the operation method of the hydrogen generator of Embodiment 1, when the oxygen concentration in the raw material increases, the raw material supplied to the hydrodesulfurizer Increase the amount of hydrogen added.

  Thereby, even if the oxygen concentration in the raw material increases, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the amount of hydrogen added to the raw material is not increased.

  The operation method of the hydrogen generator of this example may be the same as that of the first embodiment except for the above points.

[Device configuration]
The hydrogen generator 100 of the present embodiment has the same configuration as that in FIG. 1 and includes a reformer 1, a hydrodesulfurizer 2, and a controller 200. Since the configuration is the same as that of the first embodiment, description thereof is omitted.

[Operation]
FIG. 3 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 1 according to the first embodiment.

  As shown in FIG. 3, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased.

  Therefore, in this embodiment, when the oxygen concentration in the raw material increases, the amount of hydrogen added to the raw material supplied to the hydrodesulfurizer 2 is increased (step S5).

  Here, as means for increasing the amount of hydrogen added to the raw material, for example, a flow rate regulator provided on the hydrogen supply path, specifically, a variable orifice (not shown) or the like Is mentioned.

  According to the operation method of the hydrogen generator 100, when the oxygen contained in the raw material increases during the operation of the hydrogen generator 100, the amount of hydrogen added to the raw material increases, so that it is not consumed by the oxidation reaction, The amount of oxygen that oxidizes the hydrodesulfurization catalyst is reduced. Therefore, oxidative degradation of the hydrodesulfurization catalyst can be suppressed as compared with the case where the amount of hydrogen added to the raw material is not increased even if the oxygen concentration in the raw material is increased.

(Example 2)
The operation method of the hydrogen generator of Example 2 in Embodiment 1 is the hydrodesulfurization method using the hydrogen-containing gas generated in the reformer as a recycle gas in the operation method of the hydrogen generator of Embodiment 1. When the oxygen concentration in the raw material increases when the amount of hydrogen produced in the reformer is relatively small, it is added to the raw material supplied to the hydrodesulfurizer. When the amount of recycled gas is increased and the amount of hydrogen produced in the reformer is relatively large, even if the oxygen concentration in the raw material increases, it is added to the raw material supplied to the hydrodesulfurizer Do not increase the amount of recycled gas.

  This suppresses oxidative degradation of the hydrodesulfurization catalyst compared to the case where the amount of recycled gas added to the raw material is not increased even if the oxygen concentration in the raw material increases when the amount of hydrogen produced in the reformer is relatively small. Can do. In addition, a decrease in the amount of hydrogen supplied to the hydrogen-using device is suppressed as compared with a case where the amount of recycle gas is increased with an increase in the oxygen concentration in the raw material, regardless of the amount of hydrogen produced in the reformer.

  The operation method of the hydrogen generator of this example may be the same as that of the first embodiment except for the above points.

[Device configuration]
FIG. 4 is a block diagram illustrating an example of the hydrogen generator of Example 2 according to the first embodiment.

  As shown in FIG. 4, the hydrogen generator 100 includes a reformer 1, a hydrodesulfurizer 2, a recycle gas flow path 3, and a controller 200. Since the reformer 1, the hydrodesulfurizer 2, and the controller 200 are the same as those in the first embodiment, description thereof is omitted.

The recycle gas channel 3 is a channel through which a hydrogen-containing gas used for hydrodesulfurization flows. Specifically, the recycle gas flow path 3 is configured to supply the hydrogen-containing gas sent from the reformer 1 to the raw material in the raw material supply path upstream of the hydrodesulfurizer 2.
Thereby, a part of hydrogen-containing gas produced | generated by the reformer 1 can be added to the raw material before being supplied to the hydrodesulfurizer 2 as recycle gas.

  The upstream end of the recycle gas flow path 3 may be connected to any location as long as the recycle gas sent from the reformer 1 flows. For example, when a CO reducer for reducing carbon monoxide in the hydrogen-containing gas is provided downstream of the reformer 1, the upstream end of the recycle gas flow path 3 is located between the reformer 1 and the CO reducer. It may be connected to the flow path, may be connected to the CO reducer, or may be connected downstream of the CO reducer. In the case where the CO reducer includes a converter that reduces carbon monoxide by a shift reaction and a CO remover that reduces carbon monoxide by at least one of an oxidation reaction and a methanation reaction, a recycle gas flow path The upstream end of 3 may be connected to the flow path between the transformer and the CO remover. Moreover, you may connect the upstream end of the recycle gas flow path 3 to the flow path of the downstream of the hydrogen utilization apparatus using hydrogen containing gas.

[Operation]
FIG. 5 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 2 according to the first embodiment.

  As shown in FIG. 5, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased. In step S6, it is determined whether the amount of hydrogen produced in the reformer 1 is relatively small.

  Therefore, in this embodiment, when the amount of hydrogen produced in the reformer 1 is relatively small, if the oxygen concentration in the raw material increases, the recycle gas added to the raw material supplied to the hydrodesulfurizer 2 The amount is increased (step S7).

  Further, when the amount of hydrogen produced in the reformer 1 is relatively large, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer 2 is not increased even if the oxygen concentration in the raw material increases. (End).

  Here, as a means for increasing the amount of the recycle gas added to the raw material supplied to the hydrodesulfurizer 2, for example, a flow rate regulator provided on the recycle gas flow path 3, specifically, Includes a variable orifice (not shown) and the like.

  According to such an operation method of the hydrogen generator 100, when the hydrogen generation amount of the reformer 1 is relatively small, when the oxygen concentration in the raw material increases, the amount of recycle gas added to the raw material increases. The amount of oxygen that oxidizes the hydrodesulfurization catalyst is reduced without being consumed by the oxidation reaction. Therefore, even if the oxygen concentration in the raw material increases, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the amount of recycle gas added to the raw material is not increased.

  In addition, when the amount of hydrogen produced in the reformer 1 is relatively large, the flow rate of the recycle gas is relatively large. Therefore, when the oxygen concentration in the raw material is increased, the amount of the recycle gas added to the raw material is not increased. However, the degradation of the hydrodesulfurization catalyst is unlikely to proceed. Accordingly, a decrease in the amount of hydrogen supplied to the hydrogen-using device is suppressed as compared with a case where the amount of recycle gas is increased with an increase in the oxygen concentration in the raw material, regardless of the amount of hydrogen produced in the reformer.

(Example 3)
The operation method of the hydrogen generator of Example 3 in Embodiment 1 is the hydrodesulfurization method using the hydrogen-containing gas generated in the reformer as a recycle gas in the operation method of the hydrogen generator of Embodiment 1. When the oxygen concentration in the raw material increases when the amount of hydrogen produced in the reformer is relatively small when the amount of hydrogen produced in the reformer is relatively small, the amount of hydrogen produced in the reformer is increased. When the hydrogen production amount in the mass device is relatively large, even if the oxygen concentration in the raw material is increased, the hydrogen production amount in the reformer is not increased.

  As a result, when the amount of hydrogen produced in the reformer is relatively small, the oxidative degradation of the hydrodesulfurization catalyst is reduced compared to the case where the amount of hydrogen produced in the reformer is not increased even if the oxygen concentration in the raw material is increased. Can be suppressed. Also, regardless of the amount of hydrogen produced in the reformer, compared to the case where the amount of hydrogen produced is increased as the oxygen concentration in the raw material increases, the supply of hydrogen more than necessary to the hydrogen-using equipment is suppressed. Is done.

  The operation method of the hydrogen generator of this example may be the same as that of the first embodiment except for the above points.

[Device configuration]
The hydrogen generator 100 of the present embodiment has the same configuration as that shown in FIG. 4, and includes a reformer 1, a hydrodesulfurizer 2, a recycle gas flow path 3, and a controller 200. Since the configuration is the same as that of the second embodiment, the description thereof is omitted.

[Operation]
FIG. 6 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 3 according to the first embodiment.

  As shown in FIG. 6, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased. In step S6, it is determined whether the amount of hydrogen produced in the reformer 1 is relatively small.

Therefore, in this embodiment, when the amount of hydrogen generated in the reformer 1 is relatively small, the amount of hydrogen generated in the reformer 1 is increased when the oxygen concentration in the raw material is increased (step S8).
Further, when the amount of hydrogen generated in the reformer 1 is relatively large, the amount of hydrogen generated in the reformer 1 is not increased (end) even if the oxygen concentration in the raw material is increased.

  According to such an operation method of the hydrogen generator 100, when the amount of hydrogen generated in the reformer 1 is relatively small, the amount of hydrogen generated in the reformer 1 increases when the oxygen concentration in the raw material increases. For this reason, since the amount of recycle gas added to a raw material increases, it is not consumed by an oxidation reaction, but the amount of oxygen which oxidizes a hydrodesulfurization catalyst reduces. Therefore, when the amount of hydrogen produced in the reformer 1 is relatively small, the oxidative degradation of the hydrodesulfurization catalyst compared to the case where the amount of hydrogen produced in the reformer 1 is not increased even if the oxygen concentration in the raw material increases. Can be suppressed.

  Further, when the amount of hydrogen generated in the reformer 1 is relatively large, the recycle gas flow rate is relatively large. Therefore, when the oxygen concentration in the raw material is increased, the amount of hydrogen generated in the reformer 1 is not increased. However, the degradation of the hydrodesulfurization catalyst is unlikely to proceed.

  Therefore, regardless of the amount of hydrogen produced in the reformer, compared to the case where the amount of hydrogen produced is increased as the oxygen concentration in the raw material increases, the supply of hydrogen more than necessary to the hydrogen-using equipment is suppressed. Is done.

Example 4
The operation method of the hydrogen generator of Example 4 in Embodiment 1 is the hydrodesulfurization method using the hydrogen-containing gas generated in the reformer as a recycle gas in the operation method of the hydrogen generator of Embodiment 1. When the oxygen concentration in the raw material increases at the time of start-up, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer is increased and the start-up is completed. Even if the oxygen concentration in the raw material increases later, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer is not increased.

Thereby, compared with the case where the amount of recycle gas added to a raw material does not increase even if the oxygen concentration in a raw material increases at the time of starting, the oxidative degradation of a hydrodesulfurization catalyst can be suppressed. Further, regardless of whether the start-up is completed or not, a decrease in the amount of hydrogen supplied to the hydrogen-using device is suppressed as compared with a case where the amount of the recycle gas is increased with an increase in the oxygen concentration in the raw material.
The operation method of the hydrogen generator of this example may be the same as that of the first embodiment except for the above points.

[Device configuration]
The hydrogen generator 100 of the present embodiment has the same configuration as that shown in FIG. 4, and includes a reformer 1, a hydrodesulfurizer 2, a recycle gas flow path 3, and a controller 200. Since the configuration is the same as that of the second embodiment, the description thereof is omitted.

[Operation]
FIG. 7 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 4 according to the first embodiment.

  As shown in FIG. 7, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased. In step S9, it is determined whether or not the hydrogen generator 100 is activated.

  Therefore, in this embodiment, when the oxygen concentration in the raw material increases when the hydrogen generator 100 is started, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer 2 is increased (step S7). .

In addition, even if the oxygen concentration in the raw material increases after the start of the hydrogen generator 100, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer 2 is not increased (end).
Here, as means for increasing the amount of the recycle gas added to the raw material supplied to the hydrodesulfurizer 2, for example, a flow rate regulator, specifically, on the recycle gas flow path 3 is used. Examples thereof include a variable orifice (not shown) provided.

  At the time of start-up, the amount of hydrogen produced in the reformer 1 is relatively small compared to after completion of the start-up, so that the oxygen concentration in the raw material increases, so that the possibility of oxidative degradation of the hydrodesulfurization catalyst increases. According to the operation method of the hydrogen generator 100, when the oxygen concentration in the raw material increases, the amount of recycle gas added to the raw material increases, so that the amount of oxygen that is not consumed by the oxidation reaction and oxidizes the hydrodesulfurization catalyst. Is reduced. Therefore, oxidative degradation of the hydrodesulfurization catalyst can be suppressed as compared with the case where the amount of recycle gas added to the raw material is not increased even when the oxygen concentration in the raw material is increased when the hydrogen generator 100 is started.

  In addition, after the start-up is completed, the amount of hydrogen produced in the reformer 1 is relatively large compared to that at the start-up, and the recycle gas flow rate is relatively large. Therefore, when the oxygen concentration in the raw material increases, it is added to the raw material. Even if the amount of recycle gas is not increased, the degradation of the hydrodesulfurization catalyst hardly proceeds. Thereby, a decrease in the amount of hydrogen supplied to the hydrogen-using device is suppressed as compared with the case where the amount of the recycle gas is increased with an increase in the oxygen concentration in the raw material, regardless of the completion of the start-up.

  At the time of start-up, the hydrogen-containing gas generated in the reformer 1 is not consumed by the hydrogen-using device, and is used as it is as a combustion fuel for heating the reformer 1, so that the hydrogen-containing gas is used as the hydrogen-using device. The amount of combustion fuel is likely to be larger than after the start-up consumed in Therefore, in order to suppress the excessive temperature rise of the reformer 1, the amount of hydrogen generated in the reformer 1 is smaller at the start-up than after the start-up is completed.

(Example 5)
The operation method of the hydrogen generator of Example 5 in Embodiment 1 is the same as the operation method of the hydrogen generator of Embodiment 1, in which hydrodesulfurization is performed using a part of the hydrogen-containing gas generated in the reformer as a recycle gas. It is added to the raw material before being supplied to the reactor, and when the oxygen concentration in the raw material increases, the amount of water vapor relative to the raw material is reduced, and a hydrogen-containing gas is generated in the reformer.

  Thereby, even if the oxygen concentration in the raw material increases, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the amount of water vapor relative to the raw material is not reduced.

  The operation method of the hydrogen generator of this example may be the same as that of the first embodiment except for the above points.

[Device configuration]
FIG. 8 is a block diagram illustrating an example of the hydrogen generator of Example 5 according to the first embodiment.

  As shown in FIG. 8, the hydrogen generator 100 includes a reformer 1, a hydrodesulfurizer 2, a recycle gas flow path 3, and a controller 200. Since the hydrodesulfurizer 2, the recycle gas flow path 3, and the controller 200 are the same as those in the first embodiment, description thereof is omitted.

  In this embodiment, water is supplied to the reformer 1 using a water supply device (not shown). Thereby, in the reformer 1, the steam reforming reaction using the raw material and steam proceeds.

[Operation]
FIG. 9 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 5 according to the first embodiment.

  As shown in FIG. 9, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased.

Therefore, in this embodiment, when the oxygen concentration in the raw material increases, the amount of water vapor (S / C) with respect to the raw material is reduced (step S10), and a hydrogen-containing gas is generated in the reformer 1.
A hydrogen-containing gas having a high hydrogen concentration can be generated in the reformer 1 by reducing the amount of steam (S / C) relative to the raw material. Therefore, according to the operation method of the hydrogen generator 100, when the oxygen concentration in the raw material increases, the amount of hydrogen added to the raw material increases, so that the oxygen that is not consumed by the oxidation reaction and oxidizes the hydrodesulfurization catalyst. The amount is reduced. Therefore, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the S / C is not lowered even when the oxygen concentration in the raw material is increased.

(Example 6)
The operation method of the hydrogen generator of Example 6 in the first embodiment is the same as that of the hydrogen generator of Example 5, when the amount of hydrogen generated in the reformer is relatively small, the oxygen concentration in the raw material increases. Then, when the amount of water vapor relative to the raw material is reduced and the amount of hydrogen produced in the reformer is relatively large, even if the oxygen concentration in the raw material increases, the amount of water vapor relative to the raw material is not reduced.

  As a result, when the amount of hydrogen produced in the reformer is relatively small, oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the amount of water vapor relative to the raw material is not reduced even if the oxygen concentration in the raw material increases. . In addition, the possibility of carbon deposition in the reformer is suppressed as compared with the case where the amount of water vapor relative to the raw material is decreased as the oxygen concentration in the raw material increases, regardless of the amount of hydrogen produced in the reformer.

  The operation method of the hydrogen generator of this embodiment may be the same as that of Embodiment 5 except for the above points.

[Device configuration]
The hydrogen generator 100 of the present embodiment has the same configuration as that shown in FIG. 8, and includes a reformer 1, a hydrodesulfurizer 2, a recycle gas flow path 3, and a controller 200. Since the configuration is the same as that of the fifth embodiment, the description thereof is omitted.

[Operation]
FIG. 10 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 6 according to the first embodiment.

  As shown in FIG. 10, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased. In step S6, it is determined whether the amount of hydrogen produced in the reformer 1 is relatively small.

  Therefore, in this embodiment, when the amount of hydrogen produced in the reformer 1 is relatively small, the amount of water vapor (S / C) with respect to the raw material is reduced when the oxygen concentration in the raw material is increased (step S10).

  Further, when the amount of hydrogen produced in the reformer 1 is relatively large, even if the oxygen concentration in the raw material increases, the amount (S / C) of water vapor relative to the raw material is not reduced (end).

  According to the operation method of the hydrogen generator 100, when the S / C is decreased when the amount of hydrogen generated in the reformer 1 is relatively small, a hydrogen-containing gas having a high hydrogen concentration can be generated in the reformer 1. The amount of hydrogen in the recycle gas added to the raw material increases. For this reason, even if the oxygen concentration in the raw material increases, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the S / C is not lowered.

  Further, when the hydrogen production amount of the reformer 1 is relatively large, the recycle gas flow rate is relatively large. Therefore, when the oxygen concentration in the raw material is increased, the hydrogenation can be performed without reducing the S / C. The deterioration of the desulfurization catalyst is difficult to proceed. Thereby, the possibility of carbon deposition in the reformer 1 is suppressed as compared with the case where the S / C is decreased with an increase in the oxygen concentration in the raw material, regardless of the amount of hydrogen produced in the reformer 1. . This is because, when S / C decreases, carbon deposition from the raw material generally tends to occur.

(Example 7)
The operation method of the hydrogen generator of Example 7 in Embodiment 1 is the same as the operation method of the hydrogen generator of Example 5, when the oxygen concentration in the raw material increases at the time of start-up, the amount of water vapor relative to the raw material is decreased Even if the oxygen concentration in the raw material increases after completion, the amount of water vapor relative to the raw material is not reduced.

  Thereby, compared with the case where the water vapor amount with respect to the raw material is not lowered even if the oxygen concentration in the raw material increases at the time of start-up, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed. In addition, regardless of whether the start-up is completed or not, the possibility of carbon deposition in the reformer is suppressed as compared with the case where the amount of water vapor with respect to the raw material is decreased as the oxygen concentration in the raw material increases.

  The operation method of the hydrogen generator of this embodiment may be the same as that of Embodiment 5 except for the above points.

[Device configuration]
The hydrogen generator 100 of the present embodiment has the same configuration as that shown in FIG. 8, and includes a reformer 1, a hydrodesulfurizer 2, a recycle gas flow path 3, and a controller 200. Since the configuration is the same as that of the fifth embodiment, the description thereof is omitted.

[Operation]
FIG. 11 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 7 according to the first embodiment.

  As shown in FIG. 11, in step S4, it is determined whether or not the oxygen concentration in the raw material has increased. In step S9, it is determined whether or not the hydrogen generator 100 is activated.

  Therefore, in this embodiment, when the oxygen concentration in the raw material increases when the hydrogen generator 100 is started, the amount (S / C) of water vapor relative to the raw material is decreased (step S10).

  Moreover, even if the oxygen concentration in the raw material increases after the start of the hydrogen generator 100 is completed, the amount (S / C) of water vapor relative to the raw material is not reduced (end).

  At the time of start-up, the amount of hydrogen generated in the reformer 1 is relatively small as compared to after the start-up is completed, so that the possibility that the hydrodesulfurization catalyst is oxidized and deteriorated increases when the oxygen concentration in the raw material increases. According to such an operation method of the hydrogen generator 100, when the oxygen concentration in the raw material increases, the S / C is lowered, and a hydrogen-containing gas having a high hydrogen concentration is generated in the reformer 1 and added to the raw material. Since the amount of hydrogen in the recycle gas increases, the amount of oxygen that oxidizes the hydrodesulfurization catalyst is reduced without being consumed by the oxidation reaction. Therefore, even if the oxygen concentration in the raw material increases when the hydrogen generator 100 is activated, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the S / C is not lowered.

  In addition, after the start-up is completed, the amount of hydrogen generated in the reformer 1 is relatively larger than that at the time of start-up, and the recycle gas flow rate is relatively large. Therefore, when the oxygen concentration in the raw material increases, the S / C decreases. Even if not, the degradation of the hydrodesulfurization catalyst is unlikely to proceed. Accordingly, the possibility of carbon deposition in the reformer 1 is suppressed as compared with the case where the S / C is decreased with an increase in the oxygen concentration in the raw material, regardless of before and after the completion of startup. This is because, when S / C decreases, carbon deposition from the raw material generally tends to occur.

(Example 8)
The operation method of the hydrogen generator of Example 8 in the first embodiment is the same as that of the raw material when the hydrogen-containing gas is generated in the reformer at the start-up in the operation method of the hydrogen generator of the first embodiment. When the oxygen concentration of the raw material increases, the amount of hydrogen added to the raw material is increased, and the start-up is continued. Stop startup.

Thereby, at the time of start-up, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed as compared with the case where the operation is continued even if the oxygen concentration in the raw material is increased before the generation of the hydrogen-containing gas in the reformer.
The operation method of the hydrogen generator of this example may be the same as that of the first embodiment except for the above points.

[Device configuration]
The hydrogen generator 100 of the present embodiment has the same configuration as that in FIG. 1 and includes a reformer 1, a hydrodesulfurizer 2, and a controller 200. Since the configuration is the same as that of the first embodiment, description thereof is omitted.

[Operation]
FIG. 12 is a flowchart illustrating an example of the operation of the hydrogen generator of Example 8 according to the first embodiment.

  As shown in FIG. 12, in step S11, it is determined whether or not the oxygen concentration in the raw material has increased when the hydrogen generator 100 is started. In step S12, it is determined whether or not a hydrogen-containing gas is generated in the reformer 1.

  Therefore, in this embodiment, when the hydrogen generator 100 is activated, if the oxygen concentration in the raw material increases when the hydrogen-containing gas is generated in the reformer 1, the amount of hydrogen added to the raw material And the activation is continued (step S13).

  Further, when the hydrogen generator 100 is started, the start is stopped when the oxygen concentration in the raw material increases in the reformer 1 before starting the generation of the hydrogen-containing gas (step S14).

  When no hydrogen-containing gas is generated in the reformer 1 at the time of start-up, there is no hydrogen-containing gas to which the raw material is added. Therefore, when the oxygen concentration in the raw material is increased, hydrodesulfurization is performed if the operation is continued. The catalyst deteriorates. Here, according to the operation method of the hydrogen generator 100, when the hydrogen-containing gas is not generated in the reformer 1 at the time of startup, the operation is continued even if the oxygen concentration in the raw material increases. In comparison, the oxidative deterioration of the hydrodesulfurization catalyst due to oxygen can be suppressed.

(Embodiment 2)
The operation method of the fuel cell system according to the second embodiment is a fuel cell that uses a hydrogen-containing gas supplied from a hydrogen generator that performs the operation method according to any one of the first embodiment and examples 1-8. A step of generating electricity.

  Thereby, compared with the past, the oxidative degradation of a hydrodesulfurization catalyst can be suppressed.

[Device configuration]
FIG. 13 is a block diagram illustrating an example of the fuel cell system according to the second embodiment.

  As shown in FIG. 13, the fuel cell system 300 of the present embodiment includes a hydrogen generator 100 and a fuel cell 4.

  The hydrogen generator 100 of the fuel cell system 300 is the hydrogen generator 100 of any one of Embodiment 1 and Examples 1-8.

  The fuel cell 4 generates power using the hydrogen-containing gas supplied from the hydrogen generator 100. The fuel cell 4 may be of any type, and examples include a polymer electrolyte fuel cell, a solid oxide fuel cell, and a phosphoric acid fuel cell.

[Operation]
FIG. 14 is a flowchart showing an example of the operation of the fuel cell system of the second embodiment.

  As shown in FIG. 14, in the fuel cell system 300 of the present embodiment, the fuel cell 4 generates power using the hydrogen-containing gas supplied from the hydrogen generator 100 (step S15).

  According to the operation method of the fuel cell system 300, when the oxygen concentration in the raw material is increased in the operation of the hydrogen generator 100 of any one of Embodiment 1 and Examples 1-8, the oxygen concentration is higher than in the conventional case. It is possible to suppress the oxidative deterioration of the hydrodesulfurization catalyst due to.

(Embodiment 3)
The operation method of the fuel cell system according to the third embodiment includes the step of reducing the power generation amount of the fuel cell before stopping the power generation of the fuel cell in the operation method of the fuel cell system according to the second embodiment. When the oxygen concentration in the raw material increases, the amount of hydrogen added to the raw material supplied to the hydrodesulfurizer is increased.

  As a result, in the step of reducing the power generation amount of the fuel cell before power generation is stopped, the oxidative degradation of the hydrodesulfurization catalyst is compared with the case where the amount of hydrogen added to the raw material is not increased even if the oxygen concentration in the raw material is increased. Can be suppressed.

[Device configuration]
The fuel cell system 300 has the same configuration as that in FIG. 13, and includes the hydrogen generator 100 and the fuel cell 4. Since the configuration is the same as that of the second embodiment, description thereof is omitted.

[Operation]
FIG. 15 is a flowchart illustrating an example of the operation of the fuel cell system according to the third embodiment.

  First, as shown in FIG. 15, a power generation stop request for the fuel cell 4 is generated (step S16). And the electric power generation amount of the fuel cell 4 falls (step S17). Further, it is determined whether or not the oxygen concentration in the raw material has increased (step S4). Note that step S16 may be a case where the power generation stop scheduled time of the fuel cell system 300 is approaching even if a specific power generation stop request is not generated. That is, if the power generation stop of the fuel cell system 300 is approaching, the trigger is arbitrary.

  Therefore, in this embodiment, before the power generation of the fuel cell 4 is stopped, a step S17 for reducing the power generation amount of the fuel cell 4 is provided. In step S17, when the oxygen concentration in the raw material increases, the hydrodesulfurizer 2 The amount of hydrogen added to the raw material supplied to is increased (step S5).

  In step S17, since the power generation amount of the fuel cell 4 is reduced, the raw material supply amount to the reformer 1 is reduced, and the recycle gas amount is also reduced. Here, if the amount of hydrogen added to the raw material is not increased when the oxygen concentration in the raw material is increased, there is a high possibility that the hydrodesulfurization agent is oxidized and deteriorated.

  Therefore, according to the operation method of the fuel cell system 300, when the oxygen concentration in the raw material increases, the amount of hydrogen added to the raw material increases, so even if the oxygen concentration in the raw material increases, Compared with the case where the amount of hydrogen to be added is not increased, the oxidative deterioration of the hydrodesulfurization catalyst can be suppressed.

One embodiment of the present invention suppresses oxidative degradation of a hydrodesulfurization catalyst as compared with the conventional case, and is useful as an operation method of a hydrogen generator and an operation method of a fuel cell system.

DESCRIPTION OF SYMBOLS 1 Reformer 2 Hydrodesulfurizer 3 Recycle gas flow path 4 Fuel cell 100 Hydrogen generator 200 Controller 300 Fuel cell system

Claims (11)

Adding hydrogen to the raw material such that the molar ratio of hydrogen to oxygen in the raw material is greater than 2,
Supplying the hydrogen-added raw material to a hydrodesulfurizer equipped with a catalyst for oxidative degradation, and removing sulfur compounds in the raw material;
A method of operating a hydrogen generator comprising: a step of generating a hydrogen-containing gas in a reformer using a raw material that has passed through the hydrodesulfurizer. The method for operating a hydrogen generator according to claim 1, wherein when the oxygen concentration in the raw material increases, the amount of hydrogen added to the raw material supplied to the hydrodesulfurizer is increased. A part of the hydrogen-containing gas generated in the reformer is added to the raw material before being supplied to the hydrodesulfurizer as a recycle gas,
When the amount of hydrogen produced in the reformer is relatively small, when the oxygen concentration in the raw material increases, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer is increased,
When the amount of hydrogen produced in the reformer is relatively large, even if the oxygen concentration in the raw material is increased, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer is not increased. The operation method of the hydrogen generator according to claim 1. A part of the hydrogen-containing gas generated in the reformer is added to the raw material before being supplied to the hydrodesulfurizer as a recycle gas,
When the amount of hydrogen produced in the reformer is relatively small, when the oxygen concentration in the raw material is increased, the amount of hydrogen produced in the reformer is increased,
The method of operating a hydrogen generator according to claim 1, wherein when the amount of hydrogen produced in the reformer is relatively large, the amount of hydrogen produced in the reformer is not increased even if the oxygen concentration in the raw material is increased. A part of the hydrogen-containing gas generated in the reformer is added to the raw material before being supplied to the hydrodesulfurizer as a recycle gas,
When the oxygen concentration in the raw material increases at startup, the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer is increased,
The method of operating a hydrogen generator according to claim 1, wherein the amount of recycle gas added to the raw material supplied to the hydrodesulfurizer is not increased even if the oxygen concentration in the raw material increases after the start-up is completed. A part of the hydrogen-containing gas generated in the reformer is added to the raw material before being supplied to the hydrodesulfurizer as a recycle gas,
The method of operating a hydrogen generator according to claim 1, wherein when the oxygen concentration in the raw material increases, the amount of water vapor relative to the raw material is reduced to generate a hydrogen-containing gas in the reformer. When the amount of hydrogen produced in the reformer is relatively small, when the oxygen concentration in the raw material increases, the amount of water vapor relative to the raw material decreases,
The method of operating a hydrogen generator according to claim 6, wherein when the amount of hydrogen produced in the reformer is relatively large, the amount of water vapor relative to the raw material is not reduced even if the oxygen concentration in the raw material increases. When the oxygen concentration in the raw material increases at startup, the amount of water vapor relative to the raw material is reduced,
The operation method of the hydrogen generator according to claim 6, wherein the amount of water vapor relative to the raw material is not reduced even if the oxygen concentration in the raw material increases after the start-up is completed. A part of the hydrogen-containing gas generated in the reformer is added to the raw material before being supplied to the hydrodesulfurizer as a recycle gas,
At the time of start-up, when the oxygen concentration in the raw material increases when generating the hydrogen-containing gas in the reformer, the amount of recycle gas added to the raw material is increased, and the start-up is continued.
The operation method of the hydrogen generator according to claim 1, wherein at the time of start-up, the start-up is stopped when the oxygen concentration in the raw material increases before the start of the production of the hydrogen-containing gas in the reformer. A method for operating a fuel cell system, comprising: a step of generating power by a fuel cell using a hydrogen-containing gas supplied from a hydrogen generator that performs the operation method according to claim 1. Before stopping the power generation of the fuel cell, the method includes a step of reducing the power generation amount of the fuel cell, and when the oxygen concentration in the raw material increases in the step, the raw material supplied to the hydrodesulfurizer The method of operating a fuel cell system according to claim 10, wherein the amount of hydrogen added is increased.

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