WO2014157133A1

WO2014157133A1 - Method for operating hydrogen supply system, hydrogen supply equipment, and hydrogen supply system

Info

Publication number: WO2014157133A1
Application number: PCT/JP2014/058177
Authority: WO
Inventors: 菜々子小畠; 智史古田; 小林　幸雄
Original assignee: Ｊｘ日鉱日石エネルギー株式会社
Priority date: 2013-03-25
Filing date: 2014-03-25
Publication date: 2014-10-02
Also published as: JP6086976B2; JPWO2014157133A1

Abstract

A method for operating a hydrogen supply system which includes a reactor that contains a dehydrogenation catalyst and in which a feed material comprising a hydrogenated organic compound is supplied to the reactor and dehydrogenated with the catalyst to obtain hydrogen. The method includes a dehydrogenation initiation step and a dehydrogenation termination step. The method further includes a hydrogen supply step in which hydrogen is supplied to the reactor before the dehydrogenation initiation step and/or after the dehydrogenation termination step.

Description

Operation method of hydrogen supply system, hydrogen supply equipment and hydrogen supply system

Various aspects and embodiments of the present invention relate to a method for operating a hydrogen supply system, a hydrogen supply facility, and a hydrogen supply system.

As a conventional hydrogen supply system, a system that generates and supplies hydrogen from a raw material by a catalytic reaction is known (see, for example, Patent Document 1). The hydrogen supply system of Patent Document 1 includes a tank for storing a raw material aromatic hydrocarbon hydride, and a reactor for obtaining hydrogen by supplying the raw material supplied from the tank to a dehydrogenation catalyst and performing a dehydrogenation reaction. ing.

JP 2006-232607 A

In a system that obtains hydrogen using a dehydrogenation catalyst, such as the gas treatment system described in Patent Document 1, when the dehydrogenation catalyst deteriorates, the conversion rate from the raw material to hydrogen decreases. It is important to prevent this. On the other hand, before and after the dehydrogenation reaction treatment, the inside of the reactor may be filled with an inert gas such as nitrogen gas, and the dehydrogenation catalyst may be maintained without being exposed to the outside air. There is room for improvement in order to properly prevent this. In this technical field, an operation method of a hydrogen supply system, a hydrogen supply facility, and a hydrogen supply system that can suppress the deterioration of the dehydrogenation catalyst are desired.

The present inventor has found that the organic compound produced during the dehydrogenation treatment remains in the reactor even after the dehydrogenation treatment, thereby deteriorating the dehydrogenation catalyst, and has led to the present invention.

That is, the operation method according to one aspect of the present invention is an operation method of the hydrogen supply system. The hydrogen supply system has a reactor in which a catalyst is accommodated, and supplies hydrogen by supplying a raw material containing a hydride of an organic compound to the reactor and performing a dehydrogenation reaction with a dehydrogenation catalyst. The method includes a dehydrogenation reaction start step and a dehydrogenation reaction end step. In the dehydrogenation reaction start step, the supply of the raw material to the reactor is started. In the dehydrogenation completion step, the supply of the raw material to the reactor is stopped. Here, the method further includes a hydrogen supply step of supplying hydrogen to the reactor at least one before the dehydrogenation reaction start step and after the dehydrogenation reaction end step.

When a dehydrogenation process is performed using a reactor, an organic compound generated during the dehydrogenation process may remain inside the reactor even after the dehydrogenation process. In this case, the remaining organic compound reacts with the dehydrogenation catalyst, coke is deposited on the surface of the dehydrogenation catalyst, and the dehydrogenation catalyst may be deteriorated. In this operation method of the hydrogen supply system, hydrogen is supplied to the reactor at least before and after the dehydrogenation reaction process performed by supplying the raw material. For this reason, the inside of the reactor is in a state filled with hydrogen at least before and after the dehydrogenation reaction treatment. Therefore, even if the organic compound remains in the reactor after the dehydrogenation reaction treatment, in order to suppress the reaction between the supplied hydrogen and the remaining organic compound to generate carbon from the organic compound, coke Can be prevented from depositing on the surface of the dehydrogenation catalyst. Therefore, it is possible to suppress the deterioration of the dehydrogenation catalyst.

In one embodiment, in the hydrogen supply step, hydrogen obtained by dehydrogenation reaction in a reactor may be used. With this configuration, it is not necessary to separately provide a hydrogen supply source, and it is not necessary to prepare a separate gas such as nitrogen as a purge gas for the reactor. Deterioration can be suppressed.

In one embodiment, the dehydrogenation reaction start step and the dehydrogenation reaction end step may be repeatedly executed. Then, when the hydrogen supply step is executed before the dehydrogenation reaction start step, the dehydrogenation reaction end step may be executed at least once. Even in such a case, deterioration of the dehydrogenation catalyst can be suppressed.

In one embodiment, the reactor may not be opened to the atmosphere after the dehydrogenation reaction end step and before the dehydrogenation reaction start step.

In one embodiment, the dehydrogenation catalyst has pores formed on the surface, and in the hydrogen supply step, a value obtained by dividing the volume of hydrogen present in the reactor by the volume of the pores is 0.9 or more. As such, hydrogen may be supplied to the reactor. By supplying hydrogen so that it may become the said value, deterioration of a dehydrogenation catalyst can be suppressed with the minimum amount of hydrogen required.

In one embodiment, the pressure inside the reactor may be higher than atmospheric pressure. By comprising in this way, a reactor can be started up rapidly.

A hydrogen supply facility according to another aspect of the present invention is a hydrogen supply facility using the above-described operation method of the hydrogen supply system. This hydrogen supply facility has the same effect as the operation method described above.

A hydrogen supply system according to another aspect of the present invention supplies hydrogen. The hydrogen supply system includes a reactor, a raw material supply unit, a hydrogen supply unit, and a control unit. The reactor contains a dehydrogenation catalyst and generates hydrogen by dehydrogenating a raw material containing a hydride of an organic compound. The raw material supply unit supplies the raw material to the reactor. The hydrogen supply unit supplies hydrogen generated by the reactor to the reactor. The control unit controls operations of the raw material supply unit and the hydrogen supply unit. The control unit operates the raw material supply unit before starting the supply of the raw material to the reactor, and at least one after operating the raw material supply unit to stop the supply of the raw material to the reactor, The hydrogen supply unit is operated to supply hydrogen to the reactor.

Since this hydrogen supply system includes a control unit that executes the above-described operation method, the same effect as the above-described operation method can be obtained.

A hydrogen supply facility according to another aspect of the present invention is a hydrogen supply facility including the above-described hydrogen supply system. This hydrogen supply facility has the same effect as the operation method described above.

As described above, according to various aspects and embodiments of the present invention, a method for operating a hydrogen supply system and a hydrogen supply system that can suppress degradation of a dehydrogenation catalyst are provided.

It is a block diagram which shows the structure of the hydrogen supply system which concerns on one Embodiment. It is a flowchart which shows operation | movement of the hydrogen supply system which concerns on one Embodiment. It is a temperature profile of the reactor in the hydrogen supply system concerning one embodiment. It is a graph which shows the repetition frequency dependence of the MCH conversion rate in an Example and a comparative example.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a block diagram illustrating a configuration of a hydrogen supply system according to an embodiment. The hydrogen supply system 100 according to an embodiment uses a hydride of an organic compound as a raw material. The hydride of an organic compound is a liquid at room temperature, for example. Examples of hydrides of organic compounds include organic hydrides. An organic hydride is an organic compound that reversibly releases hydrogen through a catalytic reaction, for example, a saturated condensed ring hydrocarbon such as cyclohexane or decalin, for example, an aromatic hydrocarbon that is produced in large quantities in a refinery. Is a hydride reacted with. The organic hydride is not limited to an aromatic hydrogenated compound, and may be a 2-propanol system. In this case, hydrogen and acetone are produced. The organic hydride can be transported to the hydrogen supply system 100 as a liquid fuel by a tank lorry as in the case of gasoline. In this embodiment, methylcyclohexane (hereinafter referred to as MCH) is used as the organic hydride. In addition, hydrides of aromatic hydrocarbons such as cyclohexane, dimethylcyclohexane, ethylcyclohexane, decalin, methyldecalin, dimethyldecalin, and ethyldecalin can be used as the organic hydride. The hydrogen supply system 100 can supply hydrogen to a fuel cell vehicle or a hydrogen engine vehicle. In the process of hydrogen purification, a dehydrogenated product obtained by dehydrogenating a hydride of an organic compound as a raw material is removed. The dehydrogenation product is, for example, an organic compound that is liquid at room temperature. In the following, in this embodiment, a case where MCH is employed as a raw material and the dehydrogenation product removed in the process of hydrogen purification is toluene will be described as an example. Further, the dehydrogenation product may contain not only toluene but also unreacted MCH and a small amount of by-products, but when mixed with toluene, it exhibits the same behavior as toluene. Therefore, in the following description, what is referred to as “toluene” includes unreacted MCH and by-products.

As shown in FIG. 1, a hydrogen supply system 100 according to this embodiment includes an MCH tank 1, a vaporizer 2, a temperature raising device 3, a dehydrogenation reactor (reactor) 4, a gas-liquid separator 5, a toluene tank ( A raw material supply unit) 6, a refrigerator 7, a hydrogen purifier (hydrogen supply unit) 8, and a control unit 11. Further, the hydrogen supply system 100 includes transfer lines PL1 to PL11 and a pump 9.

The transport lines PL1 to PL11 are lines through which MCH, toluene, hydrogen-containing gas, or high-purity purified hydrogen gas passes. The transfer line PL1 connects the MCH tank 1 and the vaporizer 2. The transport line PL2 connects the vaporizer 2 and the temperature riser 3. The transfer line PL3 connects the temperature raising device 3 and the dehydrogenation reactor 4. The transfer line PL4 connects the dehydrogenation reactor 4 and the gas-liquid separator 5. The conveyance line PL9 connects the gas-liquid separator 5 and the toluene tank 6. The conveyance lines PL10 and PL11 connect the gas-liquid separator 5 and the refrigerator 7. The transfer lines PL5 and PL6 connect the gas-liquid separator 5 and the hydrogen purifier 8 with each other. The transfer line PL7 connects the hydrogen purifier 8 to an external hydrogen consumption device or a hydrogen supply device (not shown). The transfer line PL8 connects the hydrogen purifier 8 and the vaporizer 2. A pump 9 is provided in the transport line PL1. The transport line PL8 is provided with a pump 12 for circulating hydrogen from the hydrogen purifier 8 to the vaporizer 2. In addition, the pump 12 may be provided between the connection part of the conveyance line PL1 and the conveyance line PL8, and the vaporizer | carburetor 2. FIG.

The MCH tank 1 is a tank that stores MCH as a raw material. MCH transported from outside by a tank lorry or the like is stored in the MCH tank 1. The MCH stored in the MCH tank 1 is supplied to the vaporizer 2 by the pump 9 via the transport line PL1.

The vaporizer 2 is a device that vaporizes a liquid. The vaporizer 2 is supplied with liquid MCH from the MCH tank 1 via an injector or the like. Further, the vaporizer 2 may be supplied with liquid or gaseous hydrogen from the hydrogen purifier 8 via the transfer line PL8 as necessary. The supply of MCH and hydrogen to the vaporizer 2 can be controlled by electromagnetic valves (not shown) or the like provided in the transport line PL1 and the transport line PL8. Details of the supply control will be described later. The vaporizer 2 may be supplied with only hydrogen when only MCH is supplied, or when MCH and hydrogen are supplied. For example, when MCH and hydrogen are supplied to the vaporizer 2, the vaporized MCH and hydrogen are supplied to the temperature raising device 3 via the transport line PL2.

The heater 3 is a device that heats the gas passing through the transport line PL2 and raises the temperature of the gas. The gas heated by the temperature raising device 3 is supplied to the dehydrogenation reactor 4 through the transport line PL3.

The dehydrogenation reactor 4 is a device that obtains hydrogen by dehydrogenating MCH. The dehydrogenation reactor 4 defines a space inside, and a dehydrogenation catalyst is accommodated in the space. The dehydrogenation reactor 4 is a device that extracts hydrogen from MCH by a dehydrogenation reaction using the dehydrogenation catalyst. In addition, valves and the like are arranged at the gas inlet and outlet of the dehydrogenation reactor 4 so as to be hermetically sealed. As the dehydrogenation catalyst, for example, a catalyst in which platinum, ruthenium, palladium, rhodium, tin, rhenium, germanium or the like is supported on a porous carrier in which pores such as alumina are formed is used. The dehydrogenation catalyst may be a plate-type catalyst or a cylindrical pellet catalyst. The dehydrogenation catalyst may cause coking depending on its use and the performance may be reduced. However, the dehydrogenation catalyst can be used repeatedly by performing a recovery process to restore the original performance by calcination in the presence of oxygen. The organic hydride reaction is a reversible reaction and is subject to chemical equilibrium constraints, so the direction of the reaction changes depending on reaction conditions such as temperature or pressure. On the other hand, the dehydrogenation reaction is a reaction in which the number of molecules always increases by an endothermic reaction. Therefore, high temperature and low pressure conditions are advantageous. Therefore, a compressor for setting the dehydrogenation reactor 4 to a high pressure is not necessary. Since the dehydrogenation reaction is an endothermic reaction, the dehydrogenation reactor 4 is supplied with heat from a heat source (not shown) via a high temperature gas for heating. The dehydrogenation reactor 4 has a mechanism capable of exchanging heat between the MCH flowing in the dehydrogenation catalyst and the hot gas for heating from the heat source. The hydrogen-containing gas taken out by the dehydrogenation reactor 4 is supplied to the gas-liquid separator 5 through the transport line PL4. The hydrogen-containing gas flowing through the transfer line PL4 is supplied to the gas-liquid separator 5 in a state where the liquid toluene is contained as a mixture.

The gas-liquid separator 5 is a tank that separates toluene from the hydrogen-containing gas. The gas-liquid separator 5 stores a hydrogen-containing gas containing toluene as a mixture. The hydrogen-containing gas is transported in the order of the transport line PL11, the refrigerator 7 and PL10, is cooled by circulating through the refrigerator 7, and is gas-liquid into hydrogen as a gas and toluene as a liquid in the gas-liquid separator 5. To be separated. The toluene separated by the gas-liquid separator 5 is supplied to the toluene tank 6 via the transport line PL9. The toluene tank 6 is a tank for storing liquid toluene separated by the gas-liquid separator 5. The toluene stored in the toluene tank 6 can be recovered and used. The hydrogen-containing gas separated by the gas-liquid separator 5 is supplied to the hydrogen purifier 8 through the transport line PL5.

The hydrogen purifier 8 removes toluene, which is a dehydrogenation product, from the hydrogen-containing gas separated by the gas-liquid separator 5 by membrane separation. As a result, the hydrogen purifier 8 purifies the hydrogen-containing gas to obtain high-purity purified hydrogen gas. The hydrogen purifier 8 allows a hydrogen-containing gas pressurized to a predetermined pressure to pass through a membrane heated to a predetermined temperature, thereby removing a dehydrogenation product and obtaining a high-purity purified hydrogen gas. . The hydrogen recovery rate of the hydrogen purifier 8 by membrane separation is 85 to 95%. The separation factor of “hydrogen / toluene” of the membrane used in the hydrogen purifier 8 is preferably 1000 or more, and more preferably 10,000 or more. When the separation factor of “hydrogen / toluene” is 10,000 or more, the separation factor of “hydrogen / methane” of the membrane is 1000 or more. The high purity hydrogen gas obtained by passing through the membrane is supplied to the transfer line PL7.

The type of membrane applied to the hydrogen purifier 8 is not particularly limited, and a porous membrane or a non-porous membrane can be applied. The porous membrane may be, for example, one that is separated by molecular flow, one that is separated by surface diffusion flow, one that is separated by capillary condensation, or one that is separated by molecular sieving. As a membrane applied to the hydrogen purifier 8, for example, a metal membrane, a zeolite membrane, an inorganic membrane, or a polymer membrane can be employed. As the metal film, for example, a PbAg-based, PdCu-based, or Nb-based metal is used. As the inorganic film, for example, a silica film or a carbon film is used. For example, a polyimide film is used as the polymer film.

The pressure of the gas (purified hydrogen gas) that has passed through the membrane of the hydrogen purifier 8 is reduced, and the pressure of the non-permeated gas that has not passed through the membrane is not reduced. The non-permeate gas that has not permeated the membrane of the hydrogen purifier 8 is supplied to the transport line PL8 or the transport line PL6 as an off-gas containing hydrogen and a dehydrogenated product. Depending on the amount of hydrogen required in the dehydrogenation reactor 4, the transfer line PL 8 causes a part or all of the off-gas from the hydrogen purifier 8 to undergo a dehydrogenation reaction via the vaporizer 2 and the heater 3. Supply to vessel 4. When supplying all of the off gas to the dehydrogenation reactor 4, the off gas does not flow to the transfer line PL6. On the other hand, when a part of the off gas is supplied to the dehydrogenation reactor 4, the surplus off gas is supplied to the gas-liquid separator 5 through the transfer line PL6.

The hydrogen supply system 100 includes pressure regulating means such as a pressure regulating valve and flow rate control means such as a flow rate control valve as necessary. In this case, the reaction pressure of the dehydrogenation reactor 4 and the pressure of the membrane of the hydrogen purifier 8 can be controlled. For example, pressure regulating means and flow rate control means may be provided between the hydrogen purifier 8 and the vaporizer 2 or the dehydrogenation reactor 4. For example, it may be provided on the transport line PL8. Thereby, the pressure of the hydrogen purifier 8 and the dehydrogenation reactor 4 and the flow rate of the off gas can be optimized and stabilized.

The control unit 11 is a general computer unit that includes a CPU, a memory, a storage medium, a display device, and the like, and is connected to the components of the hydrogen supply system 100 described above and configured to be able to control each component. .

Next, the operation of the hydrogen supply system 100 according to this embodiment will be described. FIG. 2 is a flowchart showing the operation of the hydrogen supply system 100 according to the present embodiment. The control process shown in FIG. 2 can be executed by the control unit 11. Here, a case where the hydrogen supply system 100 is operated in an operation that repeats system start and system stop will be described as an example. In consideration of ease of understanding, the operation of the hydrogen supply system 100 will be described with reference to the temperature profile of the dehydrogenation reactor 4 shown in FIG. In FIG. 3, the horizontal axis represents the elapsed time based on the start timing of the flowchart shown in FIG. 2 (0 min), and the vertical axis represents the temperature of the dehydrogenation reactor 4.

As shown in FIG. 2, the hydrogen supply system 100 is first started (S10). In the process of S10, the control part 11 performs the starting process of each component so that it can be operate | moved as a pre-process of a dehydrogenation process. For example, supply of heat to the dehydrogenation reactor 4 via a heating high-temperature gas from a heat source (not shown) is started. For this reason, for example, as shown in FIG. 3, the temperature of the dehydrogenation reactor 4 starts to rise. When the process of S10 ends, the process proceeds to a determination process (S12).

In the process of S12, the control unit 11 determines whether or not the activation of the hydrogen supply system 100 is the first activation. The first activation refers to activation at a timing when a dehydrogenation catalyst is newly introduced or activation immediately after a dehydrogenation catalyst recovery process is performed. In the process of S12, when it is determined that it is not the first activation, the process proceeds to a hydrogen supply process (S14).

In the process of S14, the control unit 11 supplies hydrogen to the dehydrogenation reactor 4 (hydrogen supply step). Since the system is not fully activated at this timing, the hydrogen-containing gas cannot be supplied from the hydrogen purifier 8, so a tank (not shown) for storing purified hydrogen, a separately installed hydrogen cylinder, etc. Hydrogen is supplied to the dehydrogenation reactor 4 as a raw material supply unit. Thereby, the inside of the dehydrogenation reactor 4 can be filled with hydrogen when the dehydrogenation reactor 4 is started after the dehydrogenation reaction treatment is performed once. When the temperature of the dehydrogenation reactor 4 rises while MCH is not supplied to the dehydrogenation reactor 4 and toluene remains in the dehydrogenation reactor 4 at the time of system startup, coke is released from toluene. Occurring and covering the catalyst surface, the dehydrogenation catalyst may be deteriorated. By supplying hydrogen to the dehydrogenation reactor 4, toluene and hydrogen can be reacted, so that generation of coke can be suppressed and deterioration of the dehydrogenation catalyst can be prevented. After completion of the process of S14, the system activation is terminated when predetermined system activation conditions such as temperature and pressure are satisfied (S16). For example, when the target temperature (350 ° C.) is reached in the temperature profile of FIG. When the process of S16 ends, the process proceeds to a steady operation start process (S18).

On the other hand, in the process of S12, when it is determined that it is the first start-up, since no toluene remains in the dehydrogenation reactor 4, the system is satisfied when predetermined system start-up conditions such as temperature and pressure are satisfied. The activation is terminated (S16). When the process of S16 ends, the process proceeds to a steady operation start process (S18).

In the process of S18, the control unit 11 controls the hydrogen supply system 100 to start a steady operation of the dehydrogenation process (dehydrogenation reaction start step). The steady operation is started from the timing when MCH is supplied to the dehydrogenation reactor 4. During steady operation, MCH is supplied from the MCH tank 1 to the dehydrogenation reactor 4 via the vaporizer 2 and the temperature raising device 3. Then, the hydrogen-containing gas obtained from the dehydrogenation reactor 4 is separated in the gas-liquid separator 5 and purified by the hydrogen purifier 8. Thus, the target purified hydrogen can be obtained during steady operation. Further, hydrogen is supplied to the dehydrogenation reactor 4 using a tank (not shown) for storing purified hydrogen, a separately attached hydrogen cylinder or the like as a raw material supply unit. Alternatively, the off-gas containing hydrogen from the hydrogen purifier 8 is returned to the dehydrogenation reactor 4. In this way, during steady operation, the dehydrogenation reaction is performed while supplying MCH and hydrogen into the dehydrogenation reactor 4. In FIG. 3, the supply of MCH and hydrogen is indicated by arrows.

Then, after a predetermined period has elapsed or after obtaining a target amount of hydrogen, the control unit 11 ends the steady operation (S20: dehydrogenation reaction end step). The steady operation ends at the timing when the supply of MCH to the dehydrogenation reactor 4 is stopped. At this time, the supply of hydrogen to the dehydrogenation reactor 4 is also stopped (see FIG. 3).

The control unit 11 starts the process of stopping the system when the steady operation ends (S22). Here, the process of lowering the temperature of the dehydrogenation reactor 4 to a predetermined temperature (for example, normal temperature) is started. For example, supply of heat from a heat source (not shown) to the dehydrogenation reactor 4 is stopped.

Thereafter, as shown in FIG. 3, the controller 11 supplies hydrogen to the dehydrogenation reactor 4 and depressurizes it (S24: hydrogen supply step). Hydrogen may be supplied to the off-gas remaining in the hydrogen purifier 8, or a tank (not shown) for storing purified hydrogen, a separately attached hydrogen cylinder or the like is used as a raw material supply unit, and hydrogen is supplied to the dehydrogenation reactor 4. You may supply. Thereafter, the gas inlet / outlet valve of the dehydrogenation reactor 4 is closed and sealed. Thereby, the dehydrogenation reactor 4 is filled with hydrogen. That is, the dehydrogenation reactor 4 is not released to the atmosphere until the next system startup. When the temperature of the dehydrogenation reactor 4 decreases to a predetermined temperature (for example, room temperature), the system stop is finished (S26).

This completes the control process shown in FIG. By executing the control process shown in FIG. 2, hydrogen is supplied to the dehydrogenation reactor 4 after steady operation, that is, after the supply of MCH to the dehydrogenation reactor 4 is stopped, and the dehydrogenation reactor 4 can be reacted with the remaining toluene. Therefore, it is possible to avoid the generation of coke from the remaining toluene. Therefore, it is possible to avoid deteriorating the dehydrogenation catalyst. Further, at the start-up other than the first start-up, that is, when the dehydrogenation end step is executed at least once, there is a possibility that toluene remains in the dehydrogenation reactor 4. Therefore, except for the first start-up, hydrogen is supplied to the dehydrogenation reactor 4 before steady operation, that is, before the MCH is supplied to the dehydrogenation reactor 4, and the remaining toluene in the dehydrogenation reactor 4 Can be reacted. Therefore, it is possible to avoid the generation of coke from the remaining toluene. Therefore, it is possible to avoid deteriorating the dehydrogenation catalyst.

In addition, in the hydrogen supply step of S24, the control unit 11 is configured so that the value obtained by dividing the volume of hydrogen present in the dehydrogenation reactor 4 by the volume of the pores of the dehydrogenation catalyst is 0.9 or more. Hydrogen may be supplied to the dehydrogenation reactor 4. Details will be described below. As described above, it is considered that toluene remaining in the dehydrogenation reactor 4 causes coking of the dehydrogenation catalyst. The pore volume of the dehydrogenation catalyst is assumed to be the volume of toluene, and the void volume in the internal space of the dehydrogenation reactor 4 is assumed to be the volume of hydrogen. Thereby, the ratio between the minimum amount of hydrogen to be supplied to the dehydrogenation reactor 4 after the end of the steady operation and the amount of remaining toluene can be calculated. As a result of measurement with a plate-type catalyst (microreactor), the value of hydrogen amount / toluene amount was 10. On the other hand, as a result of measurement with a cylindrical pellet catalyst (fixed bed reactor), the value of hydrogen amount / toluene amount was 0.9. For this reason, hydrogen is supplied to the dehydrogenation reactor 4 so that the value obtained by dividing the volume of hydrogen present in the dehydrogenation reactor 4 by the volume of the pores of the dehydrogenation catalyst becomes 0.9 or more. Therefore, the dehydrogenation catalyst can be most effectively prevented from deteriorating.

As described above, according to the hydrogen supply system 100 and the operation method of the hydrogen supply system 100 according to the present embodiment, hydrogen is supplied to the dehydrogenation reactor 4 at least before and after the dehydrogenation reaction process performed by supplying MCH. Is done. For this reason, the inside of the dehydrogenation reactor 4 is in a state filled with hydrogen at least one before and after the dehydrogenation reaction treatment. Therefore, even when the organic compound remains in the dehydrogenation reactor 4 after the dehydrogenation reaction treatment, the supplied hydrogen and the remaining organic compound are prevented from reacting to generate carbon from the organic compound. Therefore, it can be avoided that coke is deposited on the surface of the dehydrogenation catalyst. Therefore, it is possible to suppress the deterioration of the dehydrogenation catalyst. In general, purging of the dehydrogenation reactor 4 is performed with an inert gas. According to the hydrogen supply system 100 and the operation method of the hydrogen supply system 100 according to the present embodiment, the hydrogen supply system 100 Since it can purge with the produced | generated hydrogen, degradation of a dehydrogenation catalyst can be suppressed with a simple structure.

Note that the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, an example has been described in which hydrogen is supplied from the hydrogen purifier 8 to the vaporizer 2 via the transfer line PL8. However, the embodiment is not limited to the above configuration, and for example, a hydrogen cylinder or the like is vaporized. 2, or purified hydrogen may be supplied to the vaporizer 2, or hydrogen may be directly supplied from the hydrogen purifier 8 to the dehydrogenation reactor 4. In the control process shown in FIG. 2, the example has been described in which hydrogen is supplied both before and after the dehydrogenation reaction process performed by supplying MCH. Furthermore, in the control process shown in FIG. 2, the example in which the hydrogen supply step is performed after starting the system, before starting the steady operation, and after finishing the steady operation and before stopping the system has been described. It may be before and after the reaction process. For example, it may be before the start of the system start or after the end of the system stop.

Also, it is not always necessary to stop the supply of hydrogen to the dehydrogenation reactor 4 in the process of S20 of FIG. For example, the supply of hydrogen may be stopped before the process of S24 is reached. Alternatively, the depressurization process shown in S24 may be performed in parallel with the process of stopping the system shown in S22 by keeping the supply of hydrogen. Even when hydrogen is continuously supplied, the end of the steady operation is determined at the timing when the supply of MCH to the dehydrogenation reactor 4 is stopped.

Further, the dehydrogenation reactor 4 may be maintained in a state where the internal pressure is at least higher than the atmospheric pressure regardless of whether or not the depressurization process of S24 is performed. As described above, the internal pressure of the dehydrogenation reactor 4 is always maintained at least higher than the atmospheric pressure, so that the dehydrogenation reaction is performed as compared with the case where the internal pressure of the dehydrogenation reactor 4 is the atmospheric pressure. The device 4 can be activated quickly. By quickly starting the dehydrogenation reactor 4, the amount of hydrogen supplied at the time of starting can be reduced. Furthermore, since repetition of pressurization and depressurization can be avoided, the load applied to the piping and the like can be reduced, and as a result, durability can be improved.

Further, the hydrogen purifier 8 is not limited to an apparatus for removing by membrane separation, and various apparatuses can be adopted. For example, when membrane separation is used as a hydrogen purification method, a hydrogen separation apparatus including a hydrogen separation membrane is used, and impurities are adsorbed when using a PSA (Pressure swinging adsorption) method or a TSA (Temperature swinging adsorption) method. It is an adsorption removal apparatus provided with a plurality of adsorption towers for storing adsorbents.

In the above embodiment, an example in which part or all of the off-gas of the hydrogen purifier 8 is supplied to the dehydrogenation reactor 4 via the vaporizer 2 and the temperature raising device 3 has been described. The method of supplying hydrogen to 4 is not limited to the above embodiment. For example, part or all of the off-gas of the hydrogen purifier 8 may be supplied to the dehydrogenation reactor 4 without passing through at least one of the vaporizer 2 and the temperature raising device 3 as indicated by the dotted line in FIG. However, hydrogen may be supplied from another hydrogen cylinder 13.

Moreover, the hydrogen supply system according to the above-described embodiment may be used for any purpose, and may be applied to, for example, a hydrogen supply facility. The hydrogen supply facility is various facilities for supplying hydrogen, and includes, for example, a hydrogen station. For example, a hydrogen supply device (compressor, cooler, or storage tank) that stores hydrogen downstream of the hydrogen purifier and supplies hydrogen to an external hydrogen consuming device (fuel cell vehicle, hydrogen vehicle, etc.) A hydrogen supply system may be used as a hydrogen station. In addition, hydrogen may be directly supplied to the hydrogen consuming device by connecting a hydrogen consuming device (such as a power generation device) downstream of the hydrogen purifier. For example, it may be used as a hydrogen supply system for a distributed power source (for example, a household power source or an emergency power source).

[Example]
Hereinafter, examples and comparative examples implemented by the present inventors will be described in order to explain the above effects.
(Confirmation of deterioration suppression effect of hydrogen dehydrogenation catalyst)
(Example 1)
The hydrogen supply system 100 was operated by the operation method described in FIG. That is, before the steady operation (before the start of MCH supply), hydrogen was supplied to the dehydrogenation reactor 4, and then the steady operation was started. Hydrogen was supplied to the dehydrogenation reactor 4 after completion of steady operation (after completion of MCH supply). A plate-type catalyst was used as the dehydrogenation catalyst. The amount of hydrogen supplied to the dehydrogenation reactor 4 was 10 times the pore volume of the dehydrogenation catalyst. The dehydrogenation reactor 4 was not opened to the atmosphere between the end of the steady operation and before the start of the steady operation.
(Example 2)
Nitrogen was supplied to the dehydrogenation reactor 4 before steady operation (before the start of MCH supply). Others were the same as Example 1.
(Example 3)
After steady operation (after completion of MCH supply), nitrogen was supplied to the dehydrogenation reactor 4. Others were the same as Example 1.
(Comparative Example 1)
Before steady operation (before the start of MCH supply), nitrogen was supplied to the dehydrogenation reactor 4, and then steady operation was started. Nitrogen was supplied to the dehydrogenation reactor 4 after completion of steady operation (after completion of MCH supply). The dehydrogenation reactor 4 was not opened to the atmosphere between the end of the steady operation and before the start of the steady operation.

The control process shown in FIG. 2 was defined as one cycle, and the cycle was repeated to evaluate the deterioration of the dehydrogenation catalyst. The deterioration of the dehydrogenation catalyst was evaluated by the MCH conversion rate. First, operation and measurement were repeated 6 times by the method of the comparative example. Then, the recovery process of the dehydrogenation catalyst was performed. Then, the operation and measurement were repeated 6 times by the method of Example 1. Thereafter, the operation and measurement were repeated three times by the method of Example 2. Thereafter, operation and measurement were repeated twice by the method of Example 3. The results are shown in FIG. The horizontal axis represents the number of repetitions, and the vertical axis represents the MCH conversion rate. The straight line shown in the figure is the result of linear fitting of plot points. As shown in FIG. 4, in the case of the method of Comparative Example 1, the slope obtained by linear fitting of the plot points was −0.9237. On the other hand, in the case of the method of Example 1, the slope obtained by linear fitting of the plot points was −0.0934. In the case of the method of Example 2, the slope obtained by linear fitting of the plot points was −0.4507. In the case of the method of Example 3, the slope obtained by linear fitting of the plot points was −0.3019. As described above, it was confirmed that Examples 1 to 3 suppressed the decrease in MCH conversion rate as compared with Comparative Example 1. Therefore, deterioration of the dehydrogenation catalyst is suppressed by supplying hydrogen to the dehydrogenation reactor 4 before at least one of the steady operation (before the start of MCH supply) and after the end of the steady operation (after the completion of MCH supply). It was confirmed that

(Confirmation of required hydrogen amount)
Example 4
A cylindrical pellet catalyst was used as the dehydrogenation catalyst. The amount of hydrogen supplied to the dehydrogenation reactor 4 was 0.9 times the volume of the pores of the dehydrogenation catalyst (lower limit of the theoretical value). Other operating conditions were the same as in Example 1.
(Comparative Example 2)
A cylindrical pellet catalyst was used as the dehydrogenation catalyst. The same amount of nitrogen as in Example 4 was supplied to the dehydrogenation reactor 4. Other operating conditions were the same as those in Comparative Example 1.

For Example 4 and Comparative Example 2, the control process shown in FIG. 2 was performed twice to evaluate the deterioration of the dehydrogenation catalyst. The deterioration of the dehydrogenation catalyst was evaluated by the MCH conversion rate with an evaluation time of 3 hours. And the fall rate of the MCH conversion rate between the 1st time and the 2nd time was computed. The results are shown in Table 1.

As shown in Table 1, the reduction rate of Example 4 was 4%, and the reduction rate of Comparative Example 2 was 21%. Therefore, even if the amount of hydrogen supplied to the dehydrogenation reactor 4 is 0.9 times the volume of the pores of the dehydrogenation catalyst (lower limit of the theoretical value), the degradation of the dehydrogenation catalyst is suppressed. It was confirmed that

DESCRIPTION OF SYMBOLS 1 ... MCH tank (raw material supply part), 2 ... Vaporizer, 3 ... Temperature rising device, 4 ... Dehydrogenation reactor (reactor), 5 ... Gas-liquid separator, 6 ... Toluene tank, 7 ... Refrigerator, 8 ... hydrogen purifier (hydrogen supply unit), 9 ... pump, 11 ... control unit, 100 ... hydrogen supply system, PL1-PL11 ... transfer line.

Claims

Operation of a hydrogen supply system having a reactor in which a dehydrogenation catalyst is housed and supplying a raw material containing a hydride of an organic compound to the reactor and dehydrogenating the dehydrogenation catalyst. A method,
A dehydrogenation reaction start step for starting supply of raw materials to the reactor;
A dehydrogenation end step for stopping the supply of the raw material to the reactor;
With
A method for operating a hydrogen supply system, further comprising a hydrogen supply step for supplying hydrogen to the reactor at least one before the dehydrogenation reaction start step and after the dehydrogenation reaction end step.
The method for operating a hydrogen supply system according to claim 1, wherein in the hydrogen supply step, hydrogen obtained by performing a dehydrogenation reaction in the reactor is used.
The dehydrogenation reaction start step and the dehydrogenation reaction end step are repeatedly executed,
The operation method of the hydrogen supply system according to claim 1 or 2, wherein when the hydrogen supply step is executed before the dehydrogenation reaction start step, the dehydrogenation reaction end step is executed at least once.
The operation method of the hydrogen supply system according to any one of claims 1 to 3, wherein the reactor is not opened to the atmosphere after the dehydrogenation reaction end step and before the dehydrogenation reaction start step.
The dehydrogenation catalyst has pores formed on the surface,
In the hydrogen supply step, hydrogen is supplied to the reactor so that a value obtained by dividing the volume of hydrogen present in the reactor by the volume of the pores is 0.9 or more. The operation | movement method of the hydrogen supply system as described in any one of these.
The operation method of the hydrogen supply system according to any one of claims 1 to 5, wherein the pressure inside the reactor is higher than atmospheric pressure.
A hydrogen supply facility using the operation method of the hydrogen supply system according to any one of claims 1 to 6.
A hydrogen supply system for supplying hydrogen,
A reactor in which a dehydrogenation catalyst is housed and hydrogen is generated by dehydrogenating a raw material containing a hydride of an organic compound;
A raw material supply unit for supplying the raw material to the reactor;
A hydrogen supply unit for supplying hydrogen produced by the reactor to the reactor;
A control unit for controlling operations of the raw material supply unit and the hydrogen supply unit;
With
The controller is
The hydrogen before at least one of operating the raw material supply unit and starting the supply of the raw material to the reactor and after operating the raw material supply unit and stopping the supply of the raw material to the reactor. Operating the supply to supply hydrogen to the reactor;
Hydrogen supply system.
A hydrogen supply facility comprising the hydrogen supply system according to claim 8.