WO2013001753A1 - Hydrogen generation device and fuel cell system - Google Patents

Abstract

A hydrogen generation device (100) comprising: a reformer (5) for generating hydrogen-containing gas from crude gas; a crude material flow path (1) through which crude gas supplied to the reformer flows; a pressure regulator (2) for lowering the pressure of the crude gas, the pressure regulator being provided to the crude material flow path; a pressure booster (3) for boosting the pressure of the crude gas having passed through the pressure regulator, the pressure booster being provided to the crude material flow path; a hydrodesulfurizer (4) for removing sulfur compounds in the crude gas having passed through the pressure regulator, the hydrodesulfurizer being provided to the crude material flow path; and a recycle flow path (6) for supplying hydrogen-containing gas generated by the reformer to the crude material flow path downstream of the pressure regulator and upstream of the hydrodesulfurizer and the pressure booster.

Description

Hydrogen generator and fuel cell system

The present invention relates to a hydrogen generator, a fuel cell system, and an operation method thereof. More specifically, the present invention relates to a hydrogen generator equipped with a hydrodesulfurizer that removes sulfur compounds in a raw material gas, and a fuel cell system.

Development of fuel cells that enable high-efficiency power generation even with small devices is being developed as a power generation system for distributed energy sources. The supply source of hydrogen gas as fuel for power generation is not maintained as a general infrastructure. Therefore, for example, a hydrogen generator that uses a source gas supplied from an existing infrastructure such as city gas or propane gas and generates a hydrogen-containing gas by a reforming reaction between the source gas and water is additionally provided.

The hydrogen generator is a reformer that reforms the raw material gas and water, a gas-shift-reaction converter that converts carbon monoxide and water vapor, and carbon monoxide, mainly air. In many cases, a configuration is provided in which a CO remover that is oxidized with an oxidizing gas is provided. In these reactors, a catalyst suitable for each reaction is used. For example, a Ru catalyst or Ni catalyst is used for the reformer, a Cu—Zn catalyst is used for the shifter, and a Ru catalyst is used for the CO remover. Yes.

Each reactor has a suitable temperature. Specifically, the reformer is often used at about 600 to 700 ° C., the transformer is used at about 350 to 200 ° C., and the CO remover is used at about 200 to 100 ° C. in many cases. In particular, in polymer electrolyte fuel cells, electrode poisoning due to carbon monoxide tends to occur. For this reason, it is necessary to suppress the carbon monoxide concentration in the supplied hydrogen-containing gas to several tens of ppm by volume or less. The CO remover reduces the carbon monoxide concentration by oxidizing carbon monoxide.

On the other hand, source gases such as city gas contain sulfur compounds. Since the sulfur compound is a poisoning substance for the reforming catalyst, it must be removed by some method. Hydrogen generators have been proposed that employ a method of removing by room temperature adsorption (see, for example, Patent Document 1) or a method of removing by hydrodesulfurization using hydrogen (see, for example, Patent Document 2). Room temperature adsorptive desulfurization is easy to handle because it does not require heating and hydrogen, but the desulfurization capacity is not large. Hydrodesulfurization requires heating and hydrogen and is not easy to handle, but has a feature of large desulfurization capacity. Here, a hydrogen generation apparatus that uses room temperature adsorptive desulfurization at start-up and switches to hydrodesulfurization after hydrogen can be generated has also been proposed (see, for example, Patent Documents 2 and 3).

Also, a hydrogen generator that uses both room temperature adsorption desulfurization and hydrodesulfurization has been proposed (see, for example, Patent Document 4).

In a hydrogen generator using a hydrodesulfurizer, a hydrogen-containing gas is supplied to a raw material supplied to the hydrodesulfurizer via a recycle channel branched from a channel through which the hydrogen-containing gas that has passed through the reformer flows. It is comprised so that.

JP 2004-228016 A Japanese Patent Laid-Open No. 1-275697 Japanese Patent No. 4264791 JP-A-8-293315

As described above, in a hydrogen generator using hydrodesulfurization, when the supply pressure of the raw material gas increases, the amount of hydrogen-containing gas flowing through the recycle flow path decreases, and the hydrodesulfurizer requires hydrodesulfurization. There is a possibility that an excessive amount of hydrogen is not supplied.

The present invention solves the above-mentioned problem, and even when the supply pressure of the raw material gas is high, a hydrogen generator and fuel in which a decrease in the flow rate of hydrogen gas flowing through the recycle channel is suppressed as compared with a conventional hydrogen generator It is an object to provide a battery and a method for operating the battery.

The present inventors have intensively studied in a hydrogen generator that employs hydrodesulfurization. As a result, the following knowledge was obtained.

When the supply pressure of the raw material gas increases, the pressure at the downstream end of the recycle channel increases, so the differential pressure between the upstream end and the downstream end of the recycle gas channel decreases, and the flow rate of the hydrogen-containing gas decreases.

Therefore, in the raw material flow path connecting the raw material gas supply source and the reformer, the pressure regulator and the booster are arranged in this order with respect to the flow direction of the raw material gas, and downstream of the recycling flow path. Connect the end to the raw material flow path from the pressure regulator to the booster. Then, even if the supply pressure of the raw material gas is high, the pressure is reduced by the pressure regulator, so that a reduction in the differential pressure between the upstream end and the downstream end of the recycle channel is suppressed.

That is, in order to solve the above problems, the hydrogen generator of the present invention includes a reformer that generates a hydrogen-containing gas from a raw material gas, a raw material channel through which the raw material gas supplied to the reformer flows, and the raw material A pressure regulator provided in the flow path for reducing the pressure of the raw material gas; a booster provided in the raw material flow path for raising the pressure of the raw material gas that has passed through the pressure regulator; and provided in the raw material flow path. A hydrodesulfurizer that removes sulfur compounds in the raw material gas that has passed through the pressure regulator, and a hydrogen-containing gas generated in the reformer downstream of the pressure regulator and the hydrodesulfurizer, and And a recycle flow path for supplying the raw material flow path upstream of the booster.

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

According to the hydrogen generation device and the fuel cell system of the present invention, even if the supply pressure of the raw material gas is high, a decrease in the flow rate of the hydrogen gas flowing through the recycle channel is suppressed as compared with the conventional hydrogen generation device.

FIG. 1 is a block diagram illustrating an example of a schematic configuration of a hydrogen generator according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the hydrogen generator according to the second embodiment. FIG. 3 is a block diagram illustrating an example of a schematic configuration of the hydrogen generator according to the third embodiment. FIG. 4 is a block diagram illustrating an example of a schematic configuration of the hydrogen generator according to the fourth embodiment. FIG. 5 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the fourth embodiment. FIG. 6 is a block diagram illustrating an example of a schematic configuration of a fuel cell system according to a modification of the fourth embodiment. FIG. 7 is a block diagram illustrating an example of a schematic configuration of a fuel cell system according to the fifth embodiment. FIG. 8 is a block diagram illustrating an example of a schematic configuration of a fuel cell system according to a modification of the fifth embodiment.

(First embodiment)
The hydrogen generator of the first embodiment includes a reformer that generates a hydrogen-containing gas from a raw material gas, a raw material channel through which the raw material gas supplied to the reformer flows, and a raw material channel. A pressure regulator that lowers the pressure, a booster that is provided in the raw material flow path and that increases the pressure of the raw material gas that has passed through the pressure regulator, and a raw material gas that is provided in the raw material flow path and that has passed through the pressure regulator. A hydrodesulfurizer that removes sulfur compounds and a recycle channel that supplies the hydrogen-containing gas generated in the reformer to the raw material channel downstream of the pressure regulator and upstream of the hydrodesulfurizer and booster And comprising.

In such a configuration, even if the supply pressure of the raw material gas is high, a decrease in the flow rate of the hydrogen gas flowing through the recycle channel is suppressed as compared with the conventional hydrogen generator.

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

In the example shown in FIG. 1, the hydrogen generator 100 of the present embodiment includes a raw material flow path 1, a pressure regulator 2 (Pressure controller), a booster 3, a hydrodesulfurizer 4, and a reformer 5. And a recycling flow path 6.

The reformer 5 generates a hydrogen-containing gas from the raw material gas by a reforming reaction. The reforming reaction may be any reforming reaction, and specifically, steam reforming reaction (steam reforming), autothermal reaction (autothermalreforming) and partial oxidation reaction (partial oxidation reforming) are exemplified. More specifically, for example, the reformer 5 includes a reforming catalyst such as a Ru catalyst or a Ni catalyst therein, and uses a raw material gas and steam supplied from a water evaporator (not shown) to reform the steam. A hydrogen-containing gas is produced by the quality reaction.

The source gas contains at least an organic compound having carbon and hydrogen as constituent elements, and specific examples thereof include hydrocarbons such as natural gas, city gas, LPG, and LNG. City gas refers to gas supplied from a gas company to households through piping. Examples of the raw material supply source include an infrastructure of these gases and a cylinder for storing these gases.

A CO reducer for reducing carbon monoxide in the hydrogen-containing gas produced by the reformer 1 may be provided downstream of the reformer 1. The CO reducer includes a shift converter having a shift catalyst that reduces carbon monoxide by a shift reaction, and CO removal that reduces carbon monoxide by at least one of an oxidation reaction and a methanation reaction. At least one of a CO remover including a catalyst is provided.

The raw material flow path 1 is a flow path through which the raw material gas supplied to the reformer 5 flows. In the example shown in FIG. 1, the raw material flow path 1 is a flow path from the supply source of the raw material gas to the reformer 5.

The pressure regulator 2 (step-down device) is provided in the raw material flow path 1 and has a function of reducing the pressure of the raw material gas. For the pressure regulator 2, for example, a governor that mechanically reduces the pressure of the raw material gas, a proportional valve that electrically adjusts the pressure of the raw material gas, and the like are used. Note that the pressure regulator 2 may have any configuration as long as the pressure of the upstream source gas can be lower than the pressure of the downstream source gas.

Further, the pressure dropped by the pressure regulator 2 may be increased as the pressure of the source gas is relatively increased. In this case, when the pressure of the source gas is relatively small (for example, 1 kPa in gauge pressure), the pressure of the source gas is not lowered by the pressure regulator.

In addition, the pressure regulator 2 is configured so that the pressure in the raw material flow path 1 connected to the downstream end of the recycle flow path is equal to the recycle flow path 6 at the upper limit of the fluctuation range of the supply pressure of the raw material gas. The pressure may be reduced to the pressure supplied to the raw material flow path 1 through. Here, as a set value of the amount of hydrogen necessary for hydrodesulfurization, for example, 1% or more is set as the volume ratio of hydrogen supplied to the raw material gas.

Further, the pressure regulator 2 may reduce the pressure of the raw material gas and lower the fluctuation range of the pressure of the raw material gas downstream thereof than the fluctuation range of the pressure of the raw material gas upstream thereof. In particular, it may be a pressure regulator that reduces the pressure of the raw material gas and adjusts it to a predetermined pressure range. Examples of the pressure regulator include a governor and a regulator.

When the source gas is city gas and the source gas supply source is city gas infrastructure, the supply pressure of the infrastructure is generally in the range of 1.0 kPa to 2.5 kPa according to JIS standards. It has been. However, by using the pressure regulator, even when such a change occurs, the pressure of the raw material gas immediately below the pressure regulator is adjusted to a range of 0.8 kPa to 1.0 kPa, for example.

When the source gas is LPG and the source of the source gas is an LPG cylinder (LPG cylinder), the supply pressure of the LPG cylinder is generally in the range of 2.0 kPa to 3.3 kPa according to JIS standards. It has been. Here, the pressure regulator may be configured such that the pressure of the raw material gas immediately below it is adjusted to the same value as when the raw material gas is city gas, for example, 0.8 kPa to 1.0 kPa. Thereby, the design is made common to different types of source gases. In addition, you may comprise so that the pressure of the raw material gas just under the pressure regulator 2 may become a different range between city gas and LPG gas.

The booster 3 is provided in the raw material flow path 1 and increases the pressure of the raw material gas that has passed through the pressure regulator 2. Specifically, a booster pump or the like is exemplified. The booster may be any device as long as the pressure of the source gas downstream can be higher than the pressure of the source gas upstream.

The hydrodesulfurizer 4 is provided in the raw material flow path 1 and removes sulfur compounds in the raw material gas that has passed through the pressure regulator 2. The hydrodesulfurizer 4 includes a hydrodesulfurization agent. Specifically, this hydrodesulfurization agent includes, for example, a CoMo catalyst that converts a sulfur compound in a raw material gas into hydrogen sulfide, and a ZnO catalyst and a CuZn catalyst that are adsorbents that adsorb the converted hydrogen sulfide. At least one of them may be used, and as a catalyst species having both a function of converting a sulfur compound into hydrogen sulfide and a function of adsorbing hydrogen sulfide, Cu—Zn—Ni-based and Cu—Zn— It is good also as a form provided with at least any one of Fe-type catalyst.

The sulfur compound may be artificially added to the raw material as an odorous component, or may be a natural sulfur compound derived from the raw material itself. Specifically, tertiary-butylmercaptan (TBM), dimethyl sulfide (DMS), tetrahydrothiophene (THT), carbonyl sulfide (COS), hydrogen sulfide (hydrogen sulfide), etc. Is exemplified.

In the example shown in FIG. 1, the booster 3 is disposed upstream of the hydrodesulfurizer 4. However, it is arbitrary which of the booster 3 and the hydrodesulfurizer 4 is disposed upstream. is there.

The recycle channel 6 is a channel for supplying the hydrogen-containing gas generated in the reformer 5 to the raw material channel 1 downstream of the pressure regulator 2 and upstream of the hydrodesulfurizer 4 and the booster 3. is there. Hereinafter, the gas flowing through the recycle channel 6 is referred to as recycle gas. In the example of FIG. 1, the recycle channel 6 branches from the channel through which the hydrogen-containing gas that has passed through the reformer 5 flows, and is connected to the raw material channel 1 from the pressure regulator 2 to the booster 3. .

Here, the upstream end of the recycle channel 6 may be connected to any location as long as the hydrogen-containing gas that has passed through the reformer 5 flows. For example, when the CO reducer is provided downstream of the reformer 1, the upstream end may be connected to a flow path from the reformer 1 to the CO reducer, or connected to the CO reducer. Or may be connected to a flow path downstream of the CO reducer. In the case where the CO reducer includes 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 recycle flow path 6 You may comprise so that the upstream end of may be connected to the flow path between a transformer and a CO remover. Moreover, you may connect the upstream end of the recycle flow path 6 to the flow path downstream of the hydrogen utilization apparatus (not shown) using hydrogen-containing gas. Here, the hydrogen-using device is a device that uses the hydrogen-containing gas supplied from the hydrogen generation apparatus 100, and examples thereof include a fuel cell and a hydrogen storage container.

Further, the downstream end of the recycle channel 6 can be used as a raw material as long as hydrogen-containing gas can be supplied to the raw material channel 1 downstream from the pressure regulator 2 and upstream from the hydrodesulfurizer 4 and the booster 3. You may provide in any location of the flow path 1. For example, in the example shown in FIG. 1, the downstream end of the recycle flow path 6 is connected to the raw material flow path 1 from the pressure regulator 2 to the booster 3. However, in the configuration in which the hydrodesulfurizer 4 is arranged upstream of the booster 3, the downstream end of the recycle channel 6 is connected to the raw material channel 1 from the pressure regulator 2 to the hydrodesulfurizer 4. Is done.

As described above, the downstream end of the recycle channel 6 is connected to the raw material channel 1 downstream from the pressure regulator 2 and upstream from the hydrodesulfurizer 4 and the booster 3. Therefore, even if the supply pressure of the raw material gas is high, the pressure is reduced downstream of the pressure regulator 2, so that a decrease in the differential pressure between the upstream end and the downstream end of the recycle channel is suppressed. Therefore, even if the supply pressure of the raw material gas is high, a decrease in the flow rate of the recycle gas is suppressed as compared with the conventional hydrogen generator.

When the supply pressure of the raw material gas is high, the output of the booster 3 is increased to reduce the pressure at the upstream end of the recycling flow path in order to suppress a decrease in the differential pressure between the upstream end and the downstream end of the recycling flow path. Although there is a method of increasing the hydrogen content, the reformer 5 generates more hydrogen-containing gas than necessary. However, as described above, when the pressure regulator 2 is used, a decrease in the differential pressure may be suppressed without increasing the output of the booster 3 and generating more hydrogen gas than necessary.

There is also a method for increasing the pressure at the upstream end of the recycle flow path by increasing the flow resistance of the hydrogen-containing gas flow path downstream from the location connected to the upstream end of the recycle flow path. The booster output required to supply gas is increased. Therefore, there is a possibility that the power consumption in the booster increases or the cost increases. However, as described above, when the pressure regulator 2 is used, even if the increase in the channel resistance of the hydrogen-containing gas channel downstream of the portion connected to the upstream end of the recycle channel is reduced, the above difference is achieved. The pressure drop may be suppressed. That is, an increase in power consumption of the booster and an increase in cost of the booster are suppressed.

Next, when the pressure regulator 2 is the above-described pressure regulator, fluctuations in the differential pressure between the upstream end and the downstream end of the recycling flow path are suppressed as compared with the case where no pressure regulator is provided. The possibility of being deficient or excessive is reduced.

For example, when the source gas is city gas, the pressure regulator 2 is not provided, and the gas pressure directly below the booster 3 is constant, the differential pressure between the upstream end and the downstream end of the recycle channel is 1 It will fluctuate with a width of .5 kPa. As a result, the flow rate of the recycled gas also varies. In some cases, the flow rate of the recycle gas is insufficient with respect to the flow rate required for hydrodesulfurization, desulfurization in the hydrodesulfurizer 4 becomes insufficient, and the reforming catalyst of the reformer 5 may be poisoned. There is sex. In some cases, the flow rate of the recycle gas becomes excessive with respect to the amount required for hydrodesulfurization, the water vapor contained in the recycle gas is excessive, and the hydrodesulfurization agent of the hydrodesulfurizer 4 is deteriorated. There is sex.

Here, when the pressure regulator is used, when the gas pressure immediately below the booster 3 is constant, the fluctuation range of the differential pressure between the upstream end and the downstream end of the recycle flow path is reduced to, for example, 0.2 kPa. The possibility that the above problem will occur is reduced.

(Second Embodiment)
In the hydrogen generator according to the first embodiment and the modification thereof, the hydrogen generator according to the second embodiment is provided with a raw material in the raw material channel upstream of the junction of the raw material channel and the recycle channel. A room temperature desulfurizer for removing sulfur compounds therein at room temperature is provided, and the pressure regulator is disposed in the raw material flow path upstream of the room temperature desulfurizer.

In such a configuration, compared with the case where the pressure regulator is disposed in the raw material flow path downstream of the room temperature desulfurization apparatus and upstream of the booster and the hydrodesulfurization apparatus, the joining portion of the raw material flow path and the recycle flow path. The position is farther than. Thereby, possibility that a pressure regulator will deteriorate with the water vapor | steam contained in the hydrogen containing gas which flows in via a recycle channel reduces.

FIG. 2 is a block diagram showing an example of a schematic configuration of the hydrogen generator according to the second embodiment. In the example shown in FIG. 2, the hydrogen generator 200 of this embodiment includes a room temperature desulfurizer 7.

The room temperature desulfurizer 7 includes an adsorbent that adsorbs sulfur compounds at room temperature. As the adsorbent, for example, activated carbon, silver zeolite (Ag-zeolite), or the like can be used. Here, the term “normal temperature” is used because it is relatively close to the normal temperature range compared to the operating temperature of the hydrodesulfurizer 4 (for example, around 300 ° C.), and the used desulfurizing agent is used as the desulfurizing agent from the normal temperature range. It is meant to include temperatures that function effectively.

In this embodiment, the raw material flow path 1 branches into two downstream of the pressure regulator 2, the second on-off valve 22 and the room temperature desulfurizer 7 are provided on one side, and the first on-off valve 21 is provided on the other side. It is done. The branched raw material flow path 1 merges downstream of the room temperature desulfurizer 7 and is connected to the booster 3 downstream of the merge portion. The room temperature desulfurizer 7 is provided in the raw material flow path 1 downstream of the pressure regulator 2 and upstream of the junction of the raw material flow path 1 and the recycle flow path 6. The upstream here refers to at least the normal temperature It means that the portion where the raw material flow path 1 where the desulfurizer 7 is provided branches is upstream of the junction of the raw material flow path 1 and the recycle flow path 6.

The first on-off valve 21 and the second on-off valve 22 function as a switch for switching to which side of the branched material flow path 1 the material that has passed through the pressure regulator 2 flows. Instead of the first on-off valve 21 and the second on-off valve 22, other switching devices such as a three-way valve may be used.

2, the second on-off valve 22 is disposed upstream of the room temperature desulfurizer 7, but the second on-off valve 22 may be disposed downstream of the room temperature desulfurizer 7.

The recycle channel 6 is provided with a third on-off valve 23.

As the first on-off valve 21, the second on-off valve 22, and the third on-off valve 23, for example, electromagnetic valves can be used.

In the hydrogen generator 200 of the second embodiment, the configuration other than the above can be configured in the same manner as that of any one of the first embodiment and its modifications. 1 and 2 are denoted by the same reference numerals and names, and detailed description thereof is omitted.

In this embodiment, when the raw material is supplied to the reformer 5 at least one of when starting and when the operation is stopped, the sulfur compound in the raw material is removed by the room temperature desulfurizer 7. Specifically, the first on-off valve 21 is closed and the second on-off valve 22 is opened so that the raw material gas that has passed through the pressure regulator 2 passes through the room temperature desulfurizer 7. Further, the third on-off valve 23 is closed.

For example, at the time of start-up, when the temperature of the reformer 5 is increased, desulfurization is performed using the room temperature desulfurizer 7, and then the generation of hydrogen-containing gas is started in the reformer 5, and then the second on-off valve 22 is closed. Then, the first on-off valve 21 and the third on-off valve 23 are opened. That is, desulfurization using the hydrodesulfurizer 4 is started.

When the operation is stopped, after the hydrogen generation operation of the hydrogen generator 100 is stopped, the raw material gas is supplied to the reformer 5 in order to compensate for a decrease in internal pressure or gas contraction of the reformer 5 due to a temperature decrease of the reformer 5. The operation of replenishing is executed. At this time, desulfurization is performed using the room temperature desulfurizer 7. The internal pressure drop of the reformer 5 occurs in the hydrogen generator 100 configured so that the gas flow path downstream of the reformer 5 is closed by the valve when the operation is stopped, and the reformer 5 is sealed. Further, the gas shrinkage of the reformer 5 occurs in the hydrogen generator 100 configured so that the gas flow path downstream of the reformer 5 is not closed so that the reformer 5 is opened to the atmosphere even after the operation is stopped.

The above operations can be executed by a controller (not shown). The configuration of the controller can be the same as in the fourth embodiment.

(Third embodiment)
The hydrogen generator of the third embodiment is the same as that of the hydrogen generator according to at least one of the first embodiment, the second embodiment, and the modifications thereof. A pressure detector for detecting the pressure of

In such a configuration, an abnormal drop in the supply pressure of the raw material gas is detected earlier than when the pressure detector is provided in the raw material flow path downstream of the pressure regulator.

FIG. 3 is a block diagram showing an example of a schematic configuration of the hydrogen generator according to the second embodiment. In the example shown in FIG. 3, the hydrogen generator 300 of this embodiment includes a pressure detector 8.

The pressure detector 8 detects the pressure in the raw material flow path 1. Specifically, for example, the pressure of the raw material gas in the raw material flow path 1 is detected by using a diaphragm type pressure sensor (diaphragm pressure censor), a bellows type pressure sensor (bellows pressure censor), or the like.

In the hydrogen generator 300 of the third embodiment, the configuration other than the above can be configured in the same manner as any one of the first embodiment, the second embodiment, and their modifications. Therefore, components common to FIGS. 1 and 3 are given the same reference numerals and names, and detailed description thereof is omitted.

In the hydrogen generator 300, the pressure detector 8 detects the gas supply pressure of the source gas supply source located upstream of the source channel 1. If the supply pressure drops abnormally for some reason due to the supply of the raw material gas, if this is left unattended, there is a possibility that the hydrogen generator 300 will be broken or abnormal.

Temporarily, since the pressure fluctuation range tends to be smaller in the downstream of the pressure regulator 2 than in the upstream, it is difficult to detect an abnormal drop in the supply pressure of the raw material compared to the upstream of the pressure regulator 2. Therefore, by arranging the pressure detector 8 in the raw material flow path 1 upstream of the pressure regulator 2, it is possible to detect the change in the supply pressure of the raw material earlier without being affected by the pressure regulator 2. it can.

The specific processing method in the case where the pressure detector 8 detects an abnormal decrease in the raw material is not particularly limited. For example, the operation of the hydrogen generator 300 may be stopped, the operation of the booster 3 may be stopped, or the raw material gas is changed by closing a not-illustrated on-off valve provided in the raw material flow path 1. Suction by the booster 3 may be prevented.

Since the flow rate control of the gas flowing through the recycle channel in the present embodiment is the same as that in the first embodiment, detailed description thereof is omitted.

(Fourth embodiment)
The hydrogen generator according to the fourth embodiment includes an on-off valve provided in the raw material flow path and a hydrogen generator in the hydrogen generator according to at least one of the first to third embodiments and their modifications. After stopping the hydrogen generation operation, the open / close valve is opened and the reformer is operated in response to a decrease in internal pressure of the reformer due to a decrease in the temperature of the reformer or a gas contraction in the reformer. And a controller for supplying the raw material gas.

Since the gas pressure downstream of the pressure regulator is lower than upstream, even if the on-off valve provided in the raw material flow path is opened, the raw material gas is not supplied to the downstream flow path of the reformer and cannot be supplemented. There is sex. In such a configuration, by opening the on-off valve and operating the booster, the possibility that the source gas is supplied to the flow path downstream of the reformer and supplemented is improved.

[Device configuration]
FIG. 4 is a block diagram illustrating an example of a schematic configuration of the hydrogen generator according to the fourth embodiment. In the example shown in FIG. 4, the hydrogen generator 400 of this embodiment includes the on-off valve 9, the pressure detector 13, and the controller 10.

The on-off valve 9 can be a solenoid valve, for example. The on-off valve 9 is communicably connected to the controller 10 and is opened and closed based on the control of the controller 10. In the example shown in FIG. 4, the on-off valve 9 is disposed in the raw material flow path 1 downstream of the booster 3 and upstream of the hydrodesulfurizer 4, but is not limited to this configuration. Can be disposed at any location as long as it is a raw material flow path 1.

In addition, after the hydrogen generation operation of the hydrogen generator 400 is stopped, the evaporation of water continues in the reformer 5, and water vapor and high-temperature gas may flow back into the raw material flow path 1. Therefore, by closing the on-off valve 9 after the hydrogen generation operation is stopped, the backflow of water vapor and high-temperature gas is prevented.

The pressure detector 13 detects the internal pressure of the reformer 5.

After stopping the hydrogen generation operation in the hydrogen generator 400, the controller 10 opens the on-off valve 9 and operates the booster 3 in response to a decrease in internal pressure due to a decrease in the temperature of the reformer 5. The raw material is supplied to the vessel 5 (hereinafter referred to as “compensation operation”).

The controller 10 only needs to have a control function, and includes an arithmetic processing unit (not shown) and a storage unit (not shown) for storing a control program. Examples of the arithmetic processing unit include an MPU and a CPU. A memory is exemplified as the storage unit. 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.

The supplementary pressure operation refers to, for example, supplying gas to the interior of the reformer so as to compensate for at least part of the pressure drop caused by the lowering of the internal temperature of the reformer after the hydrogen generator is stopped. Say to do. An amount of gas exceeding the supply pressure of the raw material upstream of the pressure regulator 2 may be supplied. More specifically, for example, if the supply pressure of the raw material upstream of the pressure regulator 2 is P1, the booster 3 is operated during the pressure compensation operation, and the internal pressure of the reformer 5 is set to P2 or more which is larger than P1. Thus, the raw material gas is supplied into the reformer 5.

As a detector for detecting the pressure inside the reformer 5, a pressure detector for detecting the pressure inside the reformer 5 may be used, but the pressure inside the reformer 5 is indirectly detected. A detector may be used. Examples of the detector that indirectly detects the pressure inside the reformer 5 include a temperature detector that detects the temperature of the reformer, and a timer that measures the elapsed time since the reformer 5 was sealed. Etc.

For example, in the case of using a temperature detector, a correlation between the temperature of the reformer 5 after sealing the reformer 5 and a decrease in internal pressure is obtained in advance through experiments or the like, and a temperature condition that requires a pressure compensation operation from this correlation Is stored in the storage unit. Then, when the detected temperature detected by the temperature detector satisfies the temperature condition stored in the storage unit, the pressure compensation operation may be executed under the control of the controller 10.

For example, when a timer is used, a correlation between an elapsed time after sealing the reformer 5 and a decrease in the internal pressure of the reformer 5 is obtained in advance by experiments or the like, and a time condition that requires a pressure compensation operation from this correlation Is stored in the storage unit. Then, if the elapsed time detected by the timer satisfies the time condition stored in the storage unit, the pressure compensation operation may be executed under the control of the controller 10.

In the hydrogen generator 400 of the fourth embodiment, the configuration other than the above can be configured similarly to any one of the first to third embodiments and their modifications. Therefore, components common to FIGS. 1 and 4 are given the same reference numerals and names, and detailed description thereof is omitted.

[Operation]
FIG. 5 is a flowchart illustrating an example of an operation method of the hydrogen generator according to the fourth embodiment. The operation shown in FIG. 5 is executed by the controller 10 controlling each part of the hydrogen generator 400.

When the hydrogen generation operation is stopped (start), the booster 3 is stopped. Moreover, the on-off valve 9 (not shown) provided in the flow path downstream of the on-off valve 9 and the reformer 5 is also closed, and the reformer 5 is sealed. The pressure detector detects the internal pressure of the reformer 5 (step S101). When the detected pressure becomes equal to or lower than the first pressure threshold value P1 (Yes in step S102), the on-off valve 9 is opened and the booster 3 is operated (step S103), and the state is maintained for a predetermined time T1. (Step S104). As a result, the raw material gas is supplied into the reformer 5 so as to compensate for the lowering of the internal pressure of the reformer 5. Thereafter, the on-off valve 9 is closed, the operation of the booster 3 is stopped (step S104), and the pressure compensation operation ends (end).

In addition, by repeating the operations in steps S101 to S105, the compensation operation may be performed in a plurality of times.

The predetermined time T1 is set so that an amount of raw material gas necessary to compensate for the decrease in internal pressure of the reformer 5 is supplied to the reformer 5. The stoppage of the supplementary pressure operation may be determined by the detected pressure of the pressure detector 13 instead of the execution time of the supplementary pressure operation. Specifically, the supplementary pressure operation is continued and stopped until the detected pressure of the pressure detector 13 becomes equal to or higher than the second pressure threshold value P2.

[Modification]
The hydrogen generator of this modification is the same as that of the first to third embodiments and the hydrogen generator according to at least one of those modifications, in the on-off valve provided in the raw material flow path, Control of opening the on-off valve and operating the booster to supply the raw material gas to the reformer against the gas contraction in the reformer due to the temperature drop of the reformer after the hydrogen generation operation is stopped With a vessel.

This modification is configured such that the reformer 5 is opened to the atmosphere after the hydrogen generation operation of the hydrogen generator 400 is stopped. Specifically, no on-off valve is provided in the path downstream of the reformer 5.

Therefore, as the temperature of the reformer 5 decreases, the gas in the reformer 5 contracts and air flows in through the flow path downstream of the reformer 5 that is open to the atmosphere, leading to oxidative degradation of the catalyst. There is a fear. The oxidation deterioration of the catalyst means at least one of oxidation deterioration of the reforming catalyst, oxidation deterioration of the shift catalyst, and oxidation deterioration of the CO removal catalyst.

Here, a method of opening the on-off valve 9 and supplying the raw material gas to the reformer 5 to suppress the inflow of outside air from the flow path downstream of the reformer 5 can be considered. Since the apparatus is provided with the pressure regulator 2, the gas pressure downstream of the pressure regulator 2 is lower than upstream. Therefore, even if the on-off valve 9 is opened, the raw material gas is not replenished to the flow path downstream of the reformer 5, and the catalyst may be oxidized and deteriorated by the outside air. Therefore, the controller 10 opens the on-off valve 9 and operates the booster 3 to compensate for gas contraction in the reformer 5. Thereby, the raw material gas is supplied to the gas flow path downstream of the reformer 5, and the possibility that the catalyst is oxidized and deteriorated is reduced.

FIG. 6 is a block diagram showing an example of a schematic configuration of a fuel cell system according to a modification of the fourth embodiment.

As shown in FIG. 6, the fuel cell system of this modification includes a temperature detector 14.

The temperature detector 14 detects the temperature of the reformer 5.

The detector for detecting the temperature of the reformer 5 may be a temperature detector for directly detecting the temperature of the reformer 5 or a detector for detecting it indirectly. Examples of the detector that indirectly detects the temperature of the reformer 5 include a timer that measures an elapsed time after the hydrogen generation operation of the hydrogen generator 400 is stopped.

In addition, in the hydrogen generator 400 of this modification, since the structure which attached | subjected the same code | symbol in FIG. 6 and FIG. 4 is the same as that of the hydrogen generator of 4th Embodiment, the detailed description is abbreviate | omitted.

Next, the operation of the hydrogen generator 400 of this modification will be described.

After stopping the hydrogen generation operation in the hydrogen generator, the controller 10 opens the on-off valve and operates the booster against the gas contraction in the reformer accompanying the temperature drop of the reformer, Supply raw material gas to the reformer (hereinafter referred to as replenishment operation).

The timing of the replenishment operation is determined based on the temperature detected by the temperature detector 14 that detects the temperature of the reformer 5.

For example, when the temperature detector 14 is used as a detector for detecting the temperature of the reformer 5, the temperature of the reformer 5 after the hydrogen generation operation of the hydrogen generator 400 is stopped and the flow path downstream of the reformer 5. A correlation with the inflow amount of outside air from is obtained in advance through experiments or the like, and a temperature condition that requires a replenishment operation is stored in the storage unit from this correlation. Then, when the detected temperature detected by the temperature detector satisfies the temperature condition stored in the storage unit, the pressure compensation operation may be executed under the control of the controller 10.

For example, when a timer is used as a detector for detecting the temperature of the reformer 5, the elapsed time after the hydrogen generation operation of the hydrogen generator is stopped and the inflow amount of outside air from the flow path downstream of the reformer 5. Is obtained in advance by experiments or the like, and a time condition that requires a replenishment operation is stored in the storage unit from this correlation. Then, when the elapsed time detected by the timer satisfies the time condition stored in the storage unit, the replenishment operation may be executed under the control of the controller 10.

The operation flow of the hydrogen generator 400 of the present modification is the flow shown in FIG. 5 except that step S102 is a step of determining whether or not the temperature detected by the temperature detector 14 is equal to or higher than a predetermined threshold T1. Since this is the same, the description thereof is omitted.

(Fifth embodiment)
A fuel cell system according to a fifth embodiment generates power using a hydrogen generator according to at least one of the first to fourth embodiments and their modifications, and a hydrogen-containing gas supplied from the hydrogen generator. And a fuel cell.

In such a configuration, even if the supply pressure of the raw material gas is high, a decrease in the flow rate of the hydrogen gas flowing through the recycle channel is suppressed as compared with the conventional hydrogen generator.

FIG. 7 is a block diagram showing an example of a schematic configuration of a fuel cell system according to the fifth embodiment. In the example shown in FIG. 7, the fuel cell system 500 of this embodiment includes a hydrogen generator 100 and the fuel cell 20.

The fuel cell 20 is a fuel cell that generates electricity using a hydrogen-containing gas supplied from a hydrogen generator. The fuel cell may be any type of fuel cell, such as a polymer electrolyte fuel cell (PEFC), a solid oxide fuel cell (SOFC), a phosphoric acid fuel cell (PAFC), etc. Can be used. In the case of a polymer electrolyte fuel cell, the reformer and the fuel cell stack are separately configured in the fuel cell unit. In the case of a solid oxide fuel cell, an indirect internal reforming type having a reforming section and a fuel cell section that perform reforming reactions individually, and an internal reforming type that also performs a reforming reaction inside the fuel cell body Any of these may be used. That is, a form in which a reformer is built in the fuel cell may be employed, and the fuel cell of the present invention includes such a form.

In the fuel cell system 500 of the fifth embodiment, the hydrogen generator 100 may be configured in the same manner as any one of the first to fourth embodiments and their modifications. Constituent elements common to FIG. 1 and FIG. 7 are given the same reference numerals and names, and detailed descriptions thereof are omitted.

[Modification]
FIG. 8 is a block diagram illustrating an example of a schematic configuration of a fuel cell system according to a modification of the fifth embodiment. In this modification, a solid oxide fuel cell (SOFC) is adopted as the fuel cell.

In the example shown in FIG. 8, the fuel cell system 500 </ b> A of the present modification includes a hydrogen generator 100, an evaporator 11, an air supplier 12, and a fuel cell main body 30.

The evaporator 11 evaporates the water supplied from the water supply source, and supplies the obtained water vapor to the reformer 5.

The air supplier 12 supplies air as an oxidant gas to the fuel cell main body 30.

The fuel cell main body 30 is a fuel cell stack, and generates electricity using hydrogen supplied from the reformer 5 and air supplied from the air supplier 12.

The reformer 5, the evaporator 11, and the fuel cell body 30 constitute a hot module 40. The entire hot module 40 is heated as a whole.

In the fuel cell system 500A of the present modification, the hydrogen generator 100 may be configured in the same manner as any one of the first to fourth embodiments and their modifications. Constituent elements common to FIG. 1 and FIG. 8 are denoted by the same reference numerals and names, and detailed description thereof is omitted.

In the example shown in FIG. 8, the recycle flow path 6 is branched from the flow path connecting the reformer 5 and the fuel cell main body 30. However, the recycle flow path 6 is not necessarily limited to such a configuration. Gas may be removed. For example, the gas inlet of the recycle flow path 6 is connected to the flow path through which off-fuel gas discharged from the fuel cell main body 30 flows, and the off-fuel gas is recycled gas from the pressure regulator 2 to the booster 3. May be supplied.

From the above description, many modifications and other embodiments of the present invention are apparent to persons skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

The hydrogen generator and fuel cell system of the present invention are capable of suppressing a decrease in the flow rate of the hydrogen gas flowing through the recycle flow path as compared with the conventional hydrogen generator even when the supply pressure of the raw material gas is high. It is useful as a battery system.

DESCRIPTION OF SYMBOLS 1 Raw material flow path 2 Pressure regulator 3 Booster 4 Hydrodesulfurizer 5 Reformer 6 Recycle flow path 7 Room temperature desulfurizer 8 Pressure detector 9 On-off valve 10 Controller 11 Evaporator 12 Air supply device 13 Pressure detector 14 Temperature detector 20 Fuel cell 21 First on-off valve 22 Second on-off valve 23 Third on-off valve 30 Fuel cell main body 40 Hot module 100 Hydrogen generator 200 Hydrogen generator 300 Hydrogen generator 400 Hydrogen generator 500 Fuel cell system

Claims (6)

A reformer that generates a hydrogen-containing gas from the source gas;
A raw material flow path through which the raw material gas supplied to the reformer flows;
A pressure regulator provided in the raw material flow path for reducing the pressure of the raw material gas;
A booster that is provided in the raw material flow path and increases the pressure of the raw material gas that has passed through the pressure regulator;
A hydrodesulfurizer that is provided in the raw material flow path and removes sulfur compounds in the raw material gas that has passed through the pressure regulator;
A recycle flow path for supplying the hydrogen-containing gas generated in the reformer to the raw material flow path downstream of the pressure regulator and upstream of the hydrodesulfurizer and the booster. Generator. The raw material flow channel upstream of the joining portion of the raw material flow channel and the recycling flow channel is provided with a normal temperature desulfurizer that removes sulfur compounds in the raw material gas at normal temperature, and the pressure regulator is the normal temperature desulfurization The hydrogen generator of Claim 1 arrange | positioned upstream of a vessel. The hydrogen generator according to claim 1 or 2, further comprising a pressure detector that detects a pressure of the raw material flow channel in the raw material flow channel upstream of the pressure regulator. The on-off valve provided in the raw material flow path and the on-off valve are opened in response to a decrease in the internal pressure of the reformer accompanying a decrease in temperature of the reformer after the hydrogen generation operation in the hydrogen generator is stopped. The hydrogen generator according to claim 1, further comprising a controller that operates the booster and supplies a raw material to the reformer. The on-off valve provided in the raw material flow path and the on-off valve against gas contraction in the reformer accompanying a temperature drop of the reformer after the hydrogen generation operation in the hydrogen generator is stopped. The hydrogen generator according to claim 1, further comprising: a controller that opens and operates the booster to supply a raw material to the reformer. A fuel cell system comprising: the hydrogen generator according to any one of claims 1 to 5; and a fuel cell that generates electric power using a hydrogen-containing gas supplied from the hydrogen generator.

Images