JP2021030135A - Gas purification apparatus, control method for the same, and hydrogen production apparatus - Google Patents

Abstract

To provide a gas purification apparatus and a control method for the same in which time required for purified gas to reach predetermined purity can be reduced at the time of restarting the apparatus, and a hydrogen production apparatus.SOLUTION: In a PSA apparatus 40, communication of a first adsorption tower 102 and a second adsorption tower 104 with outside parts (a raw gas supply passage 108, a hydrogen gas storage tank 106 and an off-gas exhaust passage 116) is shut off at the time of stoppage. This can prevent or suppress decrease of inner pressure in the first adsorption tower 102 and in the second adsorption tower 104, and prevent or suppress diffusion of impurities adhering to an adsorbent. This can reduce time required for purity of produced hydrogen gas to reach predetermined quality at the time of restarting the PSA apparatus 40.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gas purification apparatus, a control method thereof, and a hydrogen production apparatus.

Conventionally, a PSA (Pressure Swing Adsorption) device is known as an example of a gas purification device that removes impurities from a raw material gas to form a refined gas.

For example, in a hydrogen production device, the raw material hydrocarbon is reformed into a reformed gas by a steam reformer, and then supplied to a PSA device (hydrogen refiner) to remove impurities from the reformed gas and purify it into hydrogen gas. ing. Specifically, by supplying the reforming gas to the adsorption tower in which the adsorbent is arranged in the PSA apparatus, impurities in the reforming gas are adsorbed by the adsorbent, separated, and purified into hydrogen gas.

Patent Document 1 proposes a hydrogen production apparatus having a PSA apparatus having three adsorption towers. This PSA device predicts output fluctuations and controls the amount of raw material gas introduced and the time required for each process such as boosting and pressure equalization.

Japanese Unexamined Patent Publication No. 2001-279267

By the way, the PSA device may stop its operation due to inspection or the like. In this case, it is common practice to remove gas from each adsorption tower. The above patent document does not describe the control when the device is stopped.

When the operation of the PSA device is stopped with the gas removed from each adsorption tower, the internal pressure of the adsorption tower decreases, so that the impurities adhering to the adsorbent of the adsorption tower diffuse in the adsorbent. As a result, when the PSA apparatus is restarted, there is an inconvenience that the time (restart time) until impurities are removed from the adsorption tower and the purified gas having a predetermined purity can be sent out becomes long.

That is, there is room for improvement in terms of shortening the restart time after stopping the PSA device.

An object of the present invention is to provide a gas purification apparatus having a shortened restart time, a control method thereof, and a hydrogen production apparatus.

The gas purification apparatus according to claim 1 is filled with an adsorbent that adsorbs impurities in the raw material gas, and a plurality of adsorption towers that send out purified gas from which impurities have been removed from the raw material gas, and the raw material gas is charged into the adsorption tower. The raw material gas supply flow path to be supplied, the refined gas storage tank for storing the refined gas, the off gas flow path in which the off gas containing the impurities is discharged from the adsorption tower, and the raw material gas supply flow while the apparatus is stopped. It is provided with a passage, the off-gas flow path, a pressure maintaining means for shutting off the refined gas storage tank and each of the adsorption towers, and maintaining the internal pressure of each of the adsorption towers at a first predetermined value or higher.

In this gas purification device, the gas remaining in each adsorption tower is generated by shutting off the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank and each adsorption tower by the pressure maintaining means while the device is stopped. It is prevented from being discharged to the outside, and the internal pressure of each adsorption tower is maintained above the first predetermined value.

As a result, it is possible to prevent or suppress the diffusion of impurities adhering to the adsorbent in the adsorption tower while the gas purification apparatus is stopped. Therefore, when the gas purification apparatus is restarted, the time required for the purified gas to reach a predetermined purity (purity of the product gas) by removing impurities from the adsorption tower is shortened. That is, the restart time of the gas purification device is shortened.

The gas refining apparatus according to claim 2 is the gas refining apparatus according to claim 1, wherein the pressure maintaining means is an apparatus when the apparatus is stopped until the internal pressure of a part of the adsorption tower reaches a second predetermined value. After continuing the operation of, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off.

In this gas refining apparatus, when the apparatus is stopped, the operation of the apparatus is continued until the internal pressure of some of the adsorption towers becomes equal to or higher than the second predetermined value, and then the raw material gas supply flow path, the off-gas flow path, and the above. The refined gas storage tank and each of the adsorption towers are shut off.

That is, in the gas refining apparatus, since the internal pressure of some of the adsorption towers is cut off from the outside in a state of being equal to or higher than the second predetermined value, the internal pressure of the adsorption towers is maintained high while the apparatus is stopped. As a result, the diffusion of impurities is further suppressed inside the adsorbent filled inside the adsorption tower while the device is stopped. Therefore, if the start is performed in the adsorption step of the adsorption tower when the gas purification device is restarted, the refined gas having a relatively high purity is supplied to the refined gas storage tank as compared with the case of starting in the adsorption process of another adsorption tower. Will be done. As a result, the time until the refined gas stored in the gas purification storage tank reaches a predetermined purity, that is, the restart time of the gas purification apparatus is shortened.

The gas refining apparatus according to claim 3 is the gas refining apparatus according to claim 1 or 2, wherein when the pressure maintaining means stops the apparatus, the raw material gas supply flow path, the off-gas flow path, and the refined gas storage. With the tank and each of the adsorption towers shut off, at least a part of the suction towers that were in the suction step immediately before the shutoff and at least a part of the suction towers that were in the desorption step are communicated with each other.

In this gas refining apparatus, when the apparatus is stopped, the pressure maintaining means interrupts the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each adsorption tower, and adsorbs the gas immediately before the interruption. At least a part of the adsorption towers in the process and at least a part of the adsorption towers in the desorption process are communicated with each other. As a result, the internal pressure of the suction tower is averaged (equalized), and the internal pressure of some suction towers is relatively low compared to the internal pressure of other suction towers while the device is stopped, and the suction towers are sucked. It is prevented or suppressed that the diffusion of impurities adhering to the agent proceeds as compared with other adsorption towers. Therefore, when the gas purification apparatus is restarted, the time required for the purified gas to reach a predetermined purity by removing impurities from the entire adsorption tower is shortened. That is, the restart time of the gas purification device is shortened.

The gas purification apparatus according to claim 4 is the gas purification apparatus according to claim 3, wherein at least a part of the adsorption towers that were in the adsorption step are each adsorption tower that was in the adsorption step, and in the desorption step. At least a part of the adsorption towers that were present are the adsorption towers that were in the desorption step.

In this gas purification device, when the device is stopped, the pressure maintaining means shuts off the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each adsorption tower, immediately before the device is stopped. Each adsorption tower that was the adsorption process and each adsorption tower that was the desorption process are communicated.

That is, since the pressures of all the adsorption towers in the adsorption step and all the adsorption towers in the desorption step are averaged, the pressures of all the adsorption towers are further averaged. As a result, the difference in the degree of dispersion of impurities among the plurality of adsorption towers is suppressed, and the restart time of the gas purification apparatus is further shortened.

The gas refining apparatus according to claim 5 is the gas refining apparatus according to claim 1 or 2, wherein when the pressure maintaining means stops the apparatus, at least a part of the adsorption towers that were in the adsorption step are supplied with the raw material gas. The raw material gas is supplied to the adsorption tower from the flow path, the off-gas flow path, the purification gas storage tank, or the raw material gas supply flow path, and at least a part of the suction towers in the desorption step is described. After supplying the raw material gas from the raw material gas supply flow path, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off.

In this gas purification apparatus, when the apparatus is stopped, the internal pressure of the adsorption tower, which was the desorption step, is relatively low as compared with the internal pressure of the adsorption tower, which was the adsorption step.

When the apparatus is stopped, the pressure maintaining means supplies the raw material gas from the raw material gas supply flow path to at least a part of the adsorption towers in the desorption step. As a result, the internal pressure of the adsorption tower is increased immediately before the device is stopped, and the diffusion of impurities in the adsorption tower while the device is stopped is further suppressed.

On the other hand, at least a part of the adsorption towers in the adsorption step is cut off from the outside (raw material gas supply flow path, off-gas flow path, refined gas storage tank), or the raw material gas is supplied from the raw material gas supply flow path. As a result, it is possible to prevent the internal pressure of the suction tower from dropping immediately before the device is stopped. As a result, the diffusion of impurities in the adsorption tower when the device is stopped is further suppressed.

Therefore, when the gas purification device is restarted, the time for removing impurities from the entire adsorption tower is shortened, and the restart time of the gas purification device is shortened.

The gas refining apparatus according to claim 6 is the gas refining apparatus according to claim 5, wherein at least a part of the adsorption towers that were in the desorption step is each adsorption tower that was in the desorption step.

In this gas refining apparatus, when the apparatus is stopped, the raw material gas is supplied from the raw material gas supply flow path to each adsorption tower whose pressure maintaining means was in the desorption step immediately before the apparatus was stopped.

That is, since the pressure is increased by supplying the raw material gas to all the adsorption towers that were in the desorption step immediately before the device is stopped, the pressures of all the adsorption towers are further averaged. As a result, the difference in the degree of dispersion of impurities among the plurality of adsorption towers is suppressed, and the restart time of the gas purification apparatus is further shortened.

The hydrogen production apparatus according to claim 7 comprises a reformer that produces a reformed gas obtained by steam reforming hydrocarbons, a compressor that compresses the reformed gas, and a reformed gas that is compressed by the compressor. The gas purification apparatus according to any one of claims 1 to 6, wherein the raw material gas is used, and impurities are separated from the reformed gas to obtain hydrogen gas as the refined gas.

In this hydrogen production apparatus, a reformed gas obtained by steam reforming hydrocarbons as a raw material gas is compressed by a compressor and then supplied to the gas purification apparatus. In the gas purification apparatus, the reforming gas is supplied to the adsorption tower, and the hydrogen gas purified from the adsorption tower in the adsorption step is stored in the refined gas storage tank.

By the way, in the gas purification apparatus, when the apparatus is stopped, the pressure maintaining means shuts off all of the adsorption tower, the raw material gas supply flow path, the off-gas flow path, and the refined gas storage tank, and the internal pressure of each adsorption tower is set to the first predetermined value or more. To maintain. As a result, the diffusion of impurities in the adsorption tower is suppressed when the gas purification apparatus is stopped, and the time for removing impurities from the adsorption tower when the gas purification apparatus is restarted is shortened. That is, the restart time of the gas purification device can be shortened.

As a result, the productivity of the hydrogen production apparatus is improved.

The hydrogen production apparatus according to claim 8 is the hydrogen production apparatus according to claim 7, wherein when the gas purification apparatus is stopped, the raw material gas supply flow path, the off-gas flow path, the purification gas storage tank, and each of the above adsorptions. The operation of the reformer and the compressor is continued until the tower is shut off.

In this hydrogen production apparatus, when the gas purification apparatus is stopped, the operation of the apparatus may be continued and then stopped until the internal pressure of the adsorption tower during the adsorption step becomes equal to or higher than a predetermined value.

Therefore, when stopping the gas purification equipment, the reformer and compressor continue to operate until at least each adsorption tower and the outside (all of the raw material gas supply flow path, the off-gas flow path, and the refined gas storage tank) are shut off. To do. As a result, when the reforming gas is required when the gas refining apparatus is stopped, the reforming gas is surely supplied to the adsorption tower and can be refined into hydrogen gas.

The control method of the gas purification apparatus according to claim 9 is to supply the raw material gas from the raw material gas supply flow path to a part of the suction towers among the plurality of suction towers, and add impurities to the adsorbent filled in the suction towers. The refined gas that has been adsorbed to remove impurities from the raw material gas is sent to the refined gas storage tank, and at the same time, impurities are contained from the adsorbent filled in the inside of some of the other adsorption towers among the plurality of adsorption towers. In the gas purification device that discharges the off-gas to the off-gas flow path, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off while the gas purification device is stopped. , The internal pressure of each suction tower is maintained above the first predetermined value.

In this control method of the gas purification device, when the gas purification device is stopped, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank and each adsorption tower are shut off, so that the gas remaining in each adsorption tower is cut off. Is prevented from being discharged to the outside, and the internal pressure of each adsorption tower is maintained above the first predetermined value.

As a result, it is possible to prevent or suppress the diffusion of impurities adhering to the adsorbent in the adsorption tower while the gas purification apparatus is stopped. Therefore, when the gas purification apparatus is restarted, the time required for the purified gas to reach a predetermined purity (purity of the product gas) by removing impurities from the adsorption tower is shortened. That is, the restart time of the gas purification device is shortened.

The method for controlling the gas refining apparatus according to claim 10 is the method for controlling the gas refining apparatus according to claim 9, wherein when the gas refining apparatus is stopped, the internal pressure of a part of the adsorption tower reaches a second predetermined value. After continuing the operation of the apparatus, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off.

In this control method of the gas purification apparatus, when the apparatus is stopped, the operation of the apparatus is continued until the internal pressure of some of the adsorption towers becomes equal to or higher than the second predetermined value, and then the raw material gas supply flow path and the off-gas flow. The road, the refined gas storage tank, and each of the adsorption towers are shut off.

That is, when the gas refining apparatus is stopped, the internal pressure of some of the adsorption towers is kept higher than the second predetermined value and is shut off from the outside, so that the internal pressure of the adsorption tower is maintained high while the apparatus is stopped. To As a result, the diffusion of impurities is further suppressed inside the adsorbent filled inside the adsorption tower while the device is stopped. Therefore, if the start is performed in the adsorption step of the adsorption tower when the gas purification device is restarted, the refined gas having a relatively high purity is supplied to the refined gas storage tank as compared with the case of starting in the adsorption process of another adsorption tower. Will be done. As a result, the time until the refined gas stored in the gas purification storage tank reaches a predetermined purity, that is, the restart time of the gas purification apparatus is shortened.

The method for controlling the gas purification apparatus according to claim 11 is the control method for the gas purification apparatus according to claim 9 or 10, wherein when the gas purification apparatus is stopped, the raw material gas supply flow path, the off-gas flow path, and the above. With the refined gas storage tank and each of the adsorption towers shut off, at least a part of the suction towers that were in the adsorption step immediately before the shutoff and at least a part of the suction towers that were in the desorption step are communicated with each other.

In this control method of the gas purification device, when the device is stopped, the pressure maintaining means shuts off the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank and each adsorption tower, and adsorbs the gas immediately before the interruption. At least a part of the adsorption towers in the process and at least a part of the adsorption towers in the desorption process are communicated with each other.

As a result, the internal pressure of the suction tower is averaged (equalized), and the internal pressure of some suction towers is relatively low compared to the internal pressure of other suction towers while the device is stopped, and the suction towers are sucked. It is prevented or suppressed that the diffusion of impurities adhering to the agent proceeds as compared with other adsorption towers.

Therefore, when the gas purification apparatus is restarted, the time required for the purified gas to reach a predetermined purity by removing impurities from the entire adsorption tower is shortened. That is, the restart time of the gas purification device is shortened.

The method for controlling the gas purification apparatus according to claim 12 is the control method for the gas purification apparatus according to claim 11, wherein at least a part of the adsorption towers in the adsorption step is each adsorption tower in the adsorption step. At least a part of the adsorption towers in the desorption step is each adsorption tower in the desorption step.

In this control method of the gas purification device, when the device is stopped, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank and each adsorption tower are shut off, and the device is adsorbed immediately before the device is stopped. Each adsorption tower that was the process and each adsorption tower that was the desorption process are communicated.

That is, since the pressures of all the adsorption towers in the adsorption step and all the adsorption towers in the desorption step are averaged, the pressures of all the adsorption towers are further averaged. As a result, the difference in the degree of dispersion of impurities among the plurality of adsorption towers is suppressed, and the restart time of the gas purification apparatus is further shortened.

The method for controlling the gas purification apparatus according to claim 13 is the method for controlling the gas purification apparatus according to claim 9 or 10, wherein at least a part of the adsorption tower was an adsorption step when the gas purification apparatus was stopped. The raw material gas is supplied to the adsorption tower from the raw material gas supply flow path, the off gas flow path, the refined gas storage tank, or the raw material gas supply flow path, and at least a part of the above in the desorption step. After supplying the raw material gas to the adsorption tower from the raw material gas supply flow path, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off.

In this control method of the gas purification apparatus, when the apparatus is stopped, the internal pressure of the adsorption tower, which was the desorption step, is relatively low as compared with the internal pressure of the adsorption tower, which was the adsorption step. ..

Therefore, when the apparatus is stopped, the raw material gas is supplied from the raw material gas supply flow path to at least a part of the adsorption towers in the desorption step. As a result, the internal pressure of the adsorption tower rises immediately before the device is stopped, and the diffusion of impurities in the adsorption tower while the device is stopped is further suppressed.

On the other hand, at least a part of the adsorption towers in the adsorption step is cut off from the outside (raw material gas supply flow path, off-gas flow path, refined gas storage tank), or the raw material gas is supplied from the raw material gas supply flow path. This prevents or suppresses a decrease in the internal pressure of the suction tower immediately before the device is stopped. As a result, the diffusion of impurities in the adsorption tower when the device is stopped is further suppressed.

Therefore, when the gas purification device is restarted, the time for removing impurities from the entire adsorption tower is shortened, and the restart time of the gas purification device is shortened.

The method for controlling the gas purification apparatus according to claim 14 is the control method for the gas purification apparatus according to claim 13, wherein at least a part of the adsorption towers that were in the desorption step are the adsorption towers that were in the desorption step. is there.

In this control method of the gas purification device, when the device is stopped, the raw material gas is supplied from the raw material gas supply flow path to each adsorption tower which was the desorption step immediately before the device is stopped.

That is, since the adsorption tower is boosted by supplying the raw material gas to all the adsorption towers that were in the desorption step immediately before the device is stopped, the pressures of all the adsorption towers are further averaged. As a result, the difference in the degree of dispersion of impurities among the plurality of adsorption towers is suppressed, and the restart time of the gas purification apparatus is further shortened.

The control method of the gas purification apparatus according to the inventions according to claims 1 to 6, the hydrogen production apparatus according to the inventions according to claims 7 and 8, and the gas purification apparatus according to the inventions according to claims 9 to 14 has the above configuration. Therefore, it is possible to shorten the time required for the refined gas to reach a predetermined purity when the gas purification apparatus is restarted.

It is a schematic block diagram which showed the hydrogen production apparatus which concerns on 1st Embodiment. It is a schematic block diagram which showed the PSA apparatus which concerns on 1st Embodiment. It is a block diagram which showed the hardware composition of the control part of the PSA apparatus which concerns on 1st Embodiment. It is a functional block diagram of the PSA control unit which concerns on 1st Embodiment. It is a figure which shows the timing chart of the switching control of the electromagnetic on-off valve of the PSA apparatus which concerns on 1st Embodiment, and the internal pressure change of each suction tower. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the step-up process at the time of the rated operation of the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the hydrogen delivery process at the time of the rated operation of the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the open / closed state of the electromagnetic on-off valve in the purging process at the time of the rated operation of the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the exhaust stop process at the time of the rated operation of the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the pressure equalizing step at the time of the rated operation of the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the suction process which switched the suction tower at the time of the rated operation of the PSA apparatus which concerns on 1st Embodiment. It is a flowchart which shows the stop control of the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the timing chart of the switching control of the electromagnetic on-off valve at the time of stop control, and the internal pressure change of each suction tower in the PSA apparatus which concerns on 1st Embodiment. It is a figure which shows the opening-off state of the electromagnetic on-off valve in the process of stopping the hydrogen supply at the time of stop control which concerns on 1st Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the pressure equalizing step at the time of stop control of the PSA apparatus which concerns on 1st Embodiment. It is a flowchart which shows the stop control of the PSA apparatus which concerns on 2nd Embodiment. It is a figure which shows the timing chart of the switching control of the electromagnetic on-off valve at the time of stop control, and the internal pressure change of each suction tower in the PSA apparatus which concerns on 2nd Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the step of boosting with respect to the suction tower on the desorption process side at the time of stop control which concerns on 2nd Embodiment.

[First Embodiment]
The PSA apparatus according to the first embodiment and the hydrogen production apparatus to which the PSA apparatus is applied will be described with reference to FIGS. 1 to 15.

<Hydrogen production equipment>
As shown in FIG. 1, the hydrogen production apparatus 10 is compressed by a reformer 20 that generates a reformed gas steam reformed from a hydrocarbon (city gas), a compressor 30 that compresses the reformed gas, and a compressor 30 that compresses the reformed gas. It is provided with a PSA device 40 for purifying hydrogen gas by removing impurities from the reformed gas. The PSA device 40 corresponds to a "gas refining device".

Further, the hydrogen production apparatus 10 includes a pre-pressurized water separating section 50, a post-pressurized water separating section 60, and a reformer 20 described later, which separate and remove water from the reforming gas on the upstream side and the downstream side of the compressor 30, respectively. It is provided with a combustion exhaust gas water separation unit 70 that separates and removes water from the combustion exhaust gas.

The hydrogen production apparatus 10 produces hydrogen from a hydrocarbon raw material, and in the present embodiment, a case where a city gas containing methane as a main component is used as an example of the hydrocarbon raw material will be described.

(Reformer)
The reformer 20 contains hydrogen as a main component from the mixed gas by a preheating flow path that heats the city gas supplied as a raw material and water for reforming while mixing and generates a mixed gas, and a steam reforming reaction. It is provided with a reforming catalyst layer for producing the reforming gas G1. The reformed gas G1 contains hydrogen, carbon monoxide, water vapor, and methane.

Further, the reformer 20 reacts carbon monoxide contained in the reforming gas G1 with steam to generate the reforming gas G2 converted into hydrogen and carbon dioxide (an aqueous shift reaction is performed). It has a CO reforming catalyst layer. The reformed gas G2 has a configuration in which carbon monoxide is reduced as compared with the reformed gas G1. The reformed gas G2 is configured to be discharged through the reformed gas discharge pipe 24.

Further, the reformer 20 is provided with a combustion chamber 22 in which a burner is arranged, and city gas or off-gas is supplied to the burner as fuel, mixed with air in the combustion chamber 22 and burned, and the combustion exhaust gas is discharged. It is configured to be guided to the gas discharge pipe 26. The heat of combustion promotes the steam reforming reaction.

As shown in FIG. 1, the reforming gas generated in the reformer 20 flows through the pre-pressurizing water separating unit 50, the compressor 30, the post-pressurizing water separating unit 60, and the PSA device 40 in this order. That is, in the gas flow direction, the reformer 20, the pre-boost water separation unit 50, the compressor 30, the post-boost water separation unit 60, and the PSA device 40 are arranged in this order from the upstream side to the downstream side. ..

(Water separation part before boosting)
The downstream end of the reformed gas discharge pipe 24 that allows the reformed gas G2 to flow in from the reformer 20 is connected to the pre-boost water separation unit 50. A water recovery pipe 52 is connected to the bottom of the pre-boost water separation unit 50, and a connecting flow path pipe 54 is connected to the upper part of the pre-boost water separation unit 50.

A heat exchanger HE1 that exchanges heat between the water cooled by the chiller 56 and the reformed gas G2 is provided on the reformed gas discharge pipe 24.

That is, the reforming gas G2 is separated by condensing water by cooling by heat exchange with the cooling water in the heat exchanger HE1 arranged in the reforming gas discharge pipe 24 upstream of the pre-pressurizing water separation unit 50. Water (liquid phase) can be stored in the lower part of the pre-pressurization water separation unit 50. The water (liquid phase) is sent to the water recovery pipe 52. The reformed gas G3 after the water is condensed from the reformed gas G2 is sent to the connecting flow path pipe 54.

A buffer tank 58 is arranged between the pre-boost water separation unit 50 and the compressor 30 on the connecting flow path pipe 54.

(Compressor)
The compressor 30 contains a connecting flow path pipe 54 through which the reformed gas G3 from the pre-boost water separation unit 50 flows, and a reformed gas G4 in which the reformed gas G3 supplied to the post-boost water separation unit 60 is compressed. It is connected to the flowing communication flow path pipe 32. The compressor 30 compresses the reformed gas G3 supplied from the pre-pressurizing water separation unit 50, and can supply the compressed reformed gas G4 to the post-pressurizing water separation unit 60.

(Water separation part after boosting)
The downstream end of the connecting flow path pipe 32 into which the reformed gas G4 flows from the compressor 30 is connected to the water separation section 60 after boosting. A water recovery pipe 62 is connected to the bottom of the post-boost water separation unit 60, and a connecting flow path pipe 64 is connected to the upper part of the post-boost water separation unit 60.

A heat exchanger HE2 for heat exchange between the water cooled by the chiller 66 and the reforming gas G4 is provided on the connecting flow path pipe 32.

That is, the reforming gas G4 is separated by condensing water by cooling by heat exchange with the cooling water in the heat exchanger HE2 arranged in the connecting flow path pipe 32 upstream of the water separation unit 60 after pressurization, and the pressure is increased. Water (liquid phase) can be stored in the lower part of the rear water separation unit 60. The water (liquid phase) is sent to the water recovery pipe 62. The reformed gas G5 after the water is condensed from the reformed gas G4 is sent to the connecting flow path pipe 64.

A buffer tank 68 is arranged between the boosted water separation unit 60 and the PSA device 40 on the connecting flow path pipe 64.

(PSA device (outline))
The PSA device 40 includes a downstream end of a connecting flow path pipe 64 through which the reformed gas G5 from the pressurized water separation unit 60 flows, an upstream end of a hydrogen supply pipe 42 to which purified hydrogen is delivered, and a PSA device 40. It is connected to the upstream end of the off-gas supply pipe 44 to which the off-gas separated by is sent out. Further, the PSA device 40 is connected to the upstream end of the vent pipe 45 that discharges hydrogen to the outside of the hydrogen production device 10 when the internal hydrogen (gas) pressure becomes excessive.

The PSA device 40 is used as a hydrogen purifier. The PSA device 40 includes a pair of adsorption towers, and one adsorption tower performs an adsorption step of adsorbing impurities on the adsorbent, and the other adsorption tower performs a desorption step of desorbing the impurities adsorbed on the adsorbent. In addition, one adsorption tower is used for the desorption step, and the other adsorption tower is used for the adsorption step. By repeating this periodically, the reformed gas G5 is continuously separated into hydrogen and impurities containing carbon monoxide (off-gas OG), and the purified hydrogen is sent to the hydrogen supply pipe 42. is there.

On the other hand, the off-gas supply pipe 44 communicates with the combustion chamber 22 of the reformer 20. An off-gas buffer tank 46 is provided on the off-gas supply pipe 44. Therefore, the off-gas OG is configured to be supplied as fuel for the burner to the combustion chamber 22 of the reformer 20 via the off-gas buffer tank 46.

The details of the PSA device 40 will be described later. Further, the PSA device 40 corresponds to a "gas purification device".

(Combustion exhaust gas water separation part)
The downstream end of the gas discharge pipe 26 that guides the combustion exhaust gas from the combustion chamber 22 of the reformer 20 is connected to the combustion exhaust gas water separation unit 70. A water recovery pipe 72 is connected to the bottom of the combustion exhaust gas water separation unit 70, and a gas discharge pipe 74 is connected to the upper part of the combustion exhaust gas water separation unit 70.

A heat exchanger HE3 that exchanges heat between the water cooled by the chiller 76 and the combustion exhaust gas is provided on the gas discharge pipe 26.

That is, the combustion exhaust gas discharged from the combustion chamber 22 is condensed by cooling by heat exchange with the cooling water in the heat exchanger HE3 arranged in the gas discharge pipe 26 upstream of the combustion exhaust gas water separation unit 70. It is separated and water (liquid phase) can be stored in the lower part of the combustion exhaust gas water separation section 70. The water (liquid phase) is sent to the water recovery pipe 72. The combustion exhaust gas after the water is condensed is discharged from the gas discharge pipe 74 into the outside air.

The downstream ends of the water recovery pipes 52, 62, and 72 are connected to the reforming water supply pipe 80. The reforming water supply pipe 80 is provided with a water treatment device (ion exchange resin) 82 for removing the dissolved ion component. Further, an external water supply unit 84 is connected to the reforming water supply pipe 80. For example, pure water or city water is supplied from the external water supply unit 84 to the reforming water supply pipe 80.

Further, the reforming water supply pipe 80 is provided with a pump P1. The water separated by the pre-boost water separation unit 50, the post-boost water separation unit 60, the combustion exhaust gas water separation unit 70, or the water supplied from the external water supply unit 84 is supplied to the reformer 20 by the pump P1. It is a composition.

(PSA device (details))
The internal structure of the PSA device 40 will be described in detail with reference to FIG.

As shown in FIG. 2, the PSA apparatus 40 purifies the first adsorption tower 102, the second adsorption tower 104, and the reformed gas G5, respectively, in which an adsorbent for adsorbing impurities of the reformed gas G5 is arranged. It has a hydrogen gas storage tank 106 for storing the manufactured product hydrogen gas. The hydrogen gas storage tank 106 corresponds to the “refined gas storage tank”.

Further, as the adsorbent filled in the first adsorption tower 102 and the second adsorption tower 104, for example, zeolite, activated carbon, activated alumina, silica gel and the like can be considered.

In the PSA apparatus 40, on the raw material gas (reformed gas G5) supply side of the first adsorption tower 102 and the second adsorption tower 104, a raw material gas supply flow path 108 connected to a connecting flow path pipe 64 at one end and a raw material Raw material gas supply branch flow paths 110A and 110B branched from the other end of the gas supply flow path 108 and common flow paths 112A and 112B connected to the raw material gas supply branch flow paths 110A and 110B, respectively, are arranged. There is.

That is, the first adsorption tower 102 is configured so that the reforming gas G5 can be supplied from the connecting flow path pipe 64 via the raw material gas supply flow path 108, the raw material gas supply branch flow path 110A, and the common flow path 112A. ..

Similarly, the second adsorption tower 104 is configured so that the reformed gas G5 can be supplied from the connecting flow path pipe 64 via the raw material gas supply flow path 108, the raw material gas supply branch flow path 110B, and the common flow path 112B. There is.

Further, electromagnetic on-off valves 114A and 114B are arranged in the raw material gas supply branch flow paths 110A and 110B, respectively, and the first suction tower 102 and the second suction tower 104 and the raw material are opened and closed by opening and closing the electromagnetic on-off valves 114A and 114B, respectively. The structure is such that the gas supply flow path 108 (communication flow path pipe 64) is communicated with or cut off.

In the PSA device 40, on the off-gas discharge side of the first adsorption tower 102 and the second adsorption tower 104, an off-gas discharge flow path 116 having one end connected to the off-gas supply pipe 44 and a branch at the other end of the off-gas discharge flow path 116 The off-gas discharge branch flow paths 118A and 118B and the common flow paths 112A and 112B to which the off-gas discharge branch flow paths 118A and 118B are connected are provided. The off-gas discharge flow path 116 corresponds to the "off-gas flow path".

That is, the off-gas discharged from the first adsorption tower 102 is configured to be able to be sent to the off-gas supply pipe 44 via the common flow path 112A, the off-gas discharge branch flow path 118A, and the off-gas discharge flow path 116.

Similarly, the off-gas discharged from the second adsorption tower 104 is configured to be able to be sent to the off-gas supply pipe 44 via the common flow path 112B, the off-gas discharge branch flow path 118B, and the off-gas discharge flow path 116.

Electromagnetic on-off valves 120A and 120B are arranged in the off-gas discharge branch flow paths 118A and 118B, respectively, and the first suction tower 102 and the second suction tower 104 and off-gas discharge are discharged by opening and closing the electromagnetic on-off valves 120A and 120B, respectively. The structure is such that the flow path 116 (off gas supply pipe 44) is communicated with or cut off.

Further, the common flow path 112A and the common flow path 112B are connected by a connecting flow path 122.

Therefore, the first suction tower 102 and the second suction tower 104 are communicated with each other via the common flow path 112A, the connecting flow path 122, and the common flow path 112B.

A pair of electromagnetic on-off valves 124A and 124B are arranged on the connecting flow path 122, and the first suction tower 102 and the second suction tower 104 communicate with each other by opening and closing the pair of electromagnetic on-off valves 124A and 124B. Or it is a configuration that is blocked.

On the delivery side of the purified gas (product hydrogen gas) of the first adsorption tower 102 and the second adsorption tower 104, a product hydrogen gas delivery flow path 126 having one end connected to the hydrogen gas storage tank 106 and a product hydrogen gas delivery flow The product hydrogen gas delivery branch flow paths 128A and 128B to which the other end of the path 126 is connected, the common flow path 130A that communicates the product hydrogen gas delivery branch flow path 128A and the first adsorption tower 102, and the product hydrogen gas delivery branch. A common flow path 130B for communicating the flow path 128B and the second suction tower 104 is provided.

Electromagnetic on-off valves 132A and 132B are arranged on the product hydrogen gas delivery branch flow paths 128A and 128B, respectively. By opening and closing the electromagnetic on-off valves 132A and 132B, the first adsorption towers 102 and 2 are provided. The adsorption tower 104 and the hydrogen gas storage tank 106 are communicated with each other or cut off.

Further, a connecting flow path 134 for connecting the common flow paths 130A and 130B is provided between the common flow paths 130A and 130B. A locally reduced diameter orifice 136 is provided substantially in the center of the connecting flow path 134. Further, electromagnetic on-off valves 138A and 138B are arranged on both sides of the orifice 136 in the connecting flow path 134, respectively.

Therefore, by opening and closing the electromagnetic on-off valves 138A and 138B, the first suction tower 102 and the second suction tower 104 communicate with each other via the common flow path 130A, the communication flow path 134 (orifice 136), and the common flow path 130B. It is a configuration that is blocked.

Further, in the communication flow path 134, a communication flow path 140 is provided in which the common flow path 130A side of the electromagnetic on-off valve 138A and the common flow path 130B side of the electromagnetic on-off valve 138B are communicated with each other. Also, a pair of electromagnetic on-off valves 142A and 142B are arranged.

Therefore, by opening and closing the electromagnetic on-off valves 142A and 142B, the first suction tower 102 and the second suction tower 104 are communicated or cut off via the communication flow path 140 (without passing through the orifice 136). ..

One end of the product hydrogen gas supply flow path 144 is connected to the downstream side of the hydrogen gas storage tank 106, and the other end of the product hydrogen gas supply flow path 144 is connected to the hydrogen supply pipe 42.

A pressure regulator 148, a mass flow controller 150, and an electromagnetic on-off valve 152 are arranged on the product hydrogen gas supply flow path 144 from the upstream side. The mass flow controller 150 may be omitted.

The pressure regulator 148 adjusts the product hydrogen gas to a predetermined pressure and supplies it to the hydrogen gas user side.

The mass flow controller 150 adjusts the flow rate of the product hydrogen gas.

The electromagnetic on-off valve 152 communicates or shuts off the hydrogen gas storage tank 106 and the hydrogen supply pipe 42. That is, the product hydrogen gas can be supplied or cannot be supplied (cut off) to the hydrogen gas user side.

A vent flow path 154 is provided in the product hydrogen gas supply flow path 144, which branches from the upstream side of the pressure regulator 148 and is connected to the vent pipe 45 outside the PSA device 40. The vent flow path 154 is provided with a check valve 156 that is opened only when the pressure is equal to or higher than a predetermined pressure.

Therefore, when the pressure on the upstream side of the pressure regulator 148 becomes excessive in the product hydrogen gas supply flow path 144, the check valve 156 is opened, and the product hydrogen gas is produced from the vent flow path 154 via the vent pipe 45. It is configured to be discharged to the outside of the device 10.

Pressure sensors 160, 162, 164, and 166 are arranged in the raw material gas supply flow path 108, the first adsorption tower 102, the second adsorption tower 104, and the product hydrogen gas supply flow path 144, respectively.

The pressure sensor 160 arranged in the raw material gas supply flow path 108 detects the pressure of the raw material gas supplied to the PSA device 40, that is, the reformed gas G5.

Further, the internal pressures of the first suction tower 102 and the second suction tower 104 are detected by the pressure sensors 162 and 164 respectively arranged in the first suction tower 102 and the second suction tower 104, respectively.

Further, the pressure of the product hydrogen gas supplied from the PSA device 40 is detected by the pressure sensor 166 arranged between the pressure regulator 148 and the mass flow controller 150 in the product hydrogen gas supply flow path 144.

(Control unit)
The PSA device 40 has a PSA control unit 170. As shown in FIG. 3, the PSA control unit 170 includes electromagnetic on-off valves 114A, 114B, 120A, 120B, 124A, 124B, 132A, 132B, 138A, 138B, 142A, 142B, 152 (hereinafter, "electromagnetic on-off valves 114A to ..." It is connected to the pressure sensors 162 and 164 by a signal line (not shown), and opens and closes each electromagnetic on-off valve 114A to 152 based on the detected values of the pressure sensors 162 and 164 according to a stop control program described later. It controls.

The PSA control unit 170 and the electromagnetic on-off valves 114A to 152 correspond to "pressure maintaining means".

The hardware configuration of the PSA control unit 170 will be described.

As shown in FIG. 4, the PSA control unit 170 includes a CPU (CenTral Processing UniT: processor) 172, a ROM (Read Only Memory) 174, a RAM (Random Access Memory) 176, a storage 178, and an interface 180. ing. Each configuration is communicably connected to each other via bus 182.

The CPU 172 is a central arithmetic processing unit that executes various programs and controls each unit. That is, the CPU 172 reads the program from the ROM 174 or the storage 178, and executes the program using the RAM 176 as a work area. The CPU 172 controls each of the above configurations and performs various arithmetic processes according to the program recorded in the ROM 174 or the storage 178.

ROM 174 stores various programs and various data. The RAM 176 temporarily stores a program or data as a work area. The storage 178 is composed of an HDD (Hard Disk Drive) or an SSD (Solid STaTe Drive), and stores various programs including an operating system and various data.

The interface 180 is an interface for the PSA control unit 170 to connect to other devices.

(Action)
Next, the operations of the hydrogen production apparatus 10 and the PSA apparatus 40 will be described. First, the operation of the hydrogen production apparatus 10 will be described.

As shown in FIG. 1, the city gas supplied to the reformer 20 of the hydrogen production apparatus 10 is heated while being mixed with water for reforming in the preheating flow path, and is supplied to the reforming catalyst layer. In the reforming catalyst layer, the reforming gas G1 containing hydrogen as a main component is generated from the mixed gas by the steam reforming reaction by receiving the heat from the combustion exhaust gas of the combustion chamber 22. The reformed gas G1 is supplied to the CO transformation catalyst layer through the reformed gas flow path. In the CO transformation catalyst layer, carbon monoxide contained in the reformed gas reacts with water vapor and is converted into hydrogen and carbon dioxide, and the reformed gas G2 in which carbon monoxide is reduced is transferred to the reformed gas discharge pipe 24. It is sent.

At this time, in the combustion chamber 22 of the reformer 20, the supplied city gas or a gas obtained by mixing off gas and air is burned by the burner. The combustion exhaust gas is supplied from the combustion chamber 22 to the combustion exhaust gas water separation unit 70 via the gas discharge pipe 26. As shown in FIG. 1, the water contained in the combustion exhaust gas is cooled and condensed by heat exchange in the heat exchanger HE3, stored in the combustion exhaust gas water separation unit 70, and sent to the water recovery pipe 72. The combustion exhaust gas from which water is separated is discharged from the gas discharge pipe 74 into the outside air.

On the other hand, as shown in FIG. 1, the reformed gas G2 is supplied to the pre-boost water separation unit 50 via the reformed gas discharge pipe 24. In the pre-boost water separation unit 50, the condensed water is stored by cooling by heat exchange in the heat exchanger HE1 and sent to the water recovery pipe 52. The reformed gas G3 from which water is separated from the reformed gas G2 is supplied from the connecting flow path pipe 54 to the compressor 30 via the buffer tank 58, and is compressed by the compressor 30.

The reformed gas G4 in which the reformed gas G3 is compressed is supplied from the connecting flow path pipe 32 to the water separation unit 60 after boosting. After boosting the pressure, the water separation unit 60 stores the condensed water by cooling by heat exchange in the heat exchanger HE2 and sends it to the water recovery pipe 62. The reformed gas G5 in which water is separated from the reformed gas G4 is supplied from the connecting flow path pipe 64 to the PSA device 40 via the buffer tank 68.

The water sent from the pre-boost water separation unit 50, the post-boost water separation unit 60, and the combustion exhaust gas water separation unit 70 to the water recovery pipes 52, 62, and 72, respectively, is returned to the reforming water supply pipe 80. By driving the pump P1, the reforming water is supplied as reforming water from the reforming water supply pipe 80 to the reformer 20.

In the PSA device 40, a pressure swing method is adopted, in one of the pair of adsorption towers, impurities other than hydrogen are adsorbed on the adsorbent, and in the other adsorption tower, impurities adsorbed on the adsorbent are desorbed. In the PSA apparatus 40, by repeating this adsorption step and the desorption step in each adsorption tower at a fixed cycle, hydrogen and impurities are continuously separated from the reformed gas G3 to purify hydrogen.

Subsequently, the specific operation of the PSA device 40 will be described with reference to FIGS. 5 to 15.

FIG. 5 shows a timing chart showing the steps of the first suction tower 102 and the second suction tower 104, the opening / closing timing of the electromagnetic on-off valves 114A to 152, and the pressure change (solid line) of the first suction towers 102 and 104 at that time. Indicates the pressure of the first suction tower 102 (detected value of the pressure sensor 162), and the broken line schematically shows the change of the pressure of the second suction tower 104 (detected value of the pressure sensor 164).

(Rated operation)
First, the rated operation of the PSA device 40 will be described with reference to FIGS. 5 to 11. In this case, the PSA control unit 170 controls the opening and closing of the electromagnetic on-off valves 114A to 152 by reading the rated operation control program from the storage 178 and executing it.

The reformer 20 and the compressor 30 of the hydrogen production apparatus 10 are continuously operated, and the reformer gas G5 produced by the reformer 20 and compressed by the compressor 30 is continuously supplied to the PSA apparatus 40. Has been done.

The suction step will be described from the state where the suction step is started in the first suction tower 102 and the desorption step is started in the second suction tower 104. The opening and closing of each electromagnetic on-off valve is controlled by a control signal from the PSA control unit 170.

As shown in FIGS. 5 and 6, first, at time T0, the electromagnetic on-off valve 114A is opened, and the reforming gas G5 is connected to the first adsorption tower 102 from the connecting flow path pipe 64 via the raw material gas supply flow path 108. Is supplied. At this time, all the electromagnetic on-off valves 132A, 138A, and 142A located on the downstream side of the first suction tower 102 are closed. As a result, the pressure inside the first adsorption tower 102 rises (pressurization process).

Further, at time T0, the electromagnetic on-off valve 120B is opened, and the second suction tower 104 is communicated with the off-gas discharge flow path 116. As a result, the off-gas OG is discharged from the second adsorption tower 104 to the off-gas supply pipe 44 via the off-gas discharge flow path 116.

In FIG. 6, the portion of each flow path of the PSA device 40 shown by the thick line is the portion through which the gas is flowing. Further, in FIG. 6, when the electromagnetic on-off valves 114A to 152 are shown in black, the valve closed state is shown, and when the electromagnetic on-off valves 114A to 152 are shown in white, the valve open state is shown. Hereinafter, the same applies to other figures.

Next, as shown in FIGS. 5 and 7, the time when the pressure in the first adsorption tower 102 sufficiently rises, the adsorbent sufficiently adsorbs impurities, and hydrogen gas of a predetermined purity can be delivered. The electromagnetic on-off valve 132A is opened at T1. As a result, the first adsorption tower 102 and the hydrogen gas storage tank 106 are communicated with each other, and the purified hydrogen gas purified by the first adsorption tower 102 is supplied to the hydrogen gas storage tank 106 (hydrogen delivery process).

During the rated operation of the PSA device 40, the electromagnetic on-off valve 152 is always open, and the purified hydrogen gas sent from the hydrogen gas storage tank 106 is set to a predetermined pressure by the pressure regulator 148, and the mass flow controller 150 After the flow rate is set to a predetermined value, the hydrogen gas is supplied to the hydrogen gas user side via the hydrogen supply pipe 42.

Further, as shown in FIGS. 5 and 8, the electromagnetic on-off valves 138A and 138B are opened at the time T2 after the lapse of a predetermined time from the time T1. As a result, the first adsorption tower 102 or the hydrogen gas storage tank 106 and the second adsorption tower 104 communicate with each other via the orifice 136. As a result, purified hydrogen gas is supplied from the first adsorption tower 102 or the hydrogen gas storage tank 106 to the second adsorption tower 104, and impurities adhering to the adsorbent in the second adsorption tower 104 are removed by the hydrogen gas. It is discharged as off-gas from the off-gas discharge flow path 116 to the off-gas supply pipe 44 (purge process).

Further, as shown in FIGS. 5 and 9, the electromagnetic on-off valve 120B is closed at the time T3 after the lapse of a predetermined time from the time T2. That is, the communication between the second adsorption tower 104 and the off-gas discharge flow path 116 is cut off. As a result, in the second adsorption tower 104, while hydrogen gas is supplied from the orifice 136, the discharge of off-gas is stopped, so that the internal pressure rises (exhaust stop process).

Further, as shown in FIGS. 5 and 10, the electromagnetic on-off valves 114A, 132A, 138A, and 138B are closed at the time T4 after the lapse of a predetermined time from the time T3. As a result, the first adsorption tower 102 is cut off from the raw material gas supply flow path 108, and is also cut off from the hydrogen gas storage tank 106 and the orifice 136.

As a result, the reformed gas is no longer supplied to the first adsorption tower 102, and the refined hydrogen gas is also stopped from being sent from the first adsorption tower 102 to the hydrogen gas storage tank 106.

Further, the communication between the first suction tower 102 and the second suction tower 104 via the orifice 136 is also cut off.

At this timing, the electromagnetic on-off valves 124A and 124B and the electromagnetic on-off valves 142A and 142B are opened. As a result, the upstream side of the first suction tower 102 and the upstream side of the second suction tower 104, the downstream side of the first suction tower 102 and the downstream side of the second suction tower 104 are communicated with each other.

In this way, the pressure is equalized by communicating the first suction tower 102 and the second suction tower 104 on the upstream side and the downstream side without passing through the orifice 136 (pressure equalization step).

Further, as shown in FIGS. 5 and 11, at the time T5 after a predetermined time elapses from the time T4, the electromagnetic on-off valves 124A and 124B and the electromagnetic on-off valves 142A and 142B are closed, and the first suction tower 102 and the second suction tower 102 and the second are closed. Communication with the suction tower 104 is cut off.

At the same time, the electromagnetic on-off valve 114B is opened, the second suction tower 104 and the raw material gas supply flow path 108 are communicated with each other, and the communication flow path pipe 64 is changed to the second suction tower 104 via the raw material gas supply flow path 108. Quality gas G5 is supplied.

Further, the electromagnetic on-off valve 120A is opened, the first suction tower 102 and the off-gas discharge flow path 116 are communicated with each other, and the off-gas is discharged from the first suction tower 102 to the off-gas supply pipe 44 via the off-gas discharge flow path 116. To

Hereinafter, similarly to the timing from time T0 to time T5, the opening / closing control of the electromagnetic on-off valve is performed at the timing from time T5 to time T10, so that the desorption step and the pressure equalizing step are performed in the first suction tower 102. , The suction step and the pressure equalizing step are performed in the second suction tower 104. Since the operation is the same only by replacing the adsorption tower, detailed description thereof will be omitted.

After that, this control is repeated while switching between the first suction tower 102 and the second suction tower 104.

As shown in FIG. 5, in the PSA device 40, the first threshold pressure Th1 is set to a pressure slightly higher than the maximum pressure values of the first suction tower 102 and the second suction tower 104 during the rated operation. There is.

This is because the check valve 156 opens when the pressure of the first suction tower 102 and the second suction tower 104 becomes higher than the first threshold pressure Th1 due to some abnormality during the rated operation period of the PSA device 40. As a result, hydrogen is discharged from the hydrogen gas storage tank 106 to the outside of the hydrogen production apparatus 10 via the vent flow path 154 and the vent pipe 45.

Further, the PSA device 40 has a pressure slightly lower than the maximum pressure values of the first suction tower 102 and the second suction tower 104 during the rated operation (for example, the maximum pressure value of 90) for use during the stop processing described later. The second threshold pressure Th2 is set to (about%). This second threshold pressure Th2 corresponds to the "second predetermined value".

In the "rated operation of the PSA device", one of the first suction tower 102 and the second suction tower 104 performs a suction step, the other performs a desorption step, then one performs a desorption step, and the other sucks. It refers to the operation of repeating the process. When switching the adsorption tower (adsorption step and desorption step) as in the present embodiment, the one that sandwiches the pressure equalizing step is also included. Further, the switching of each process may be any of time control, pressure control, and time pressure combined control.

(At the time of stop signal input) (At the time of stop control)
Next, a case where the PSA device 40 is stopped during the rated operation will be described with reference to FIGS. 12 to 15. In the present embodiment, "stopping the PSA device 40" means a state in which the power of the PSA device 40 is turned off and the electromagnetic on-off valves 114A to 152 cannot be switched. Further, in the present embodiment, "when stopping the PSA device 40" refers to a period from when a stop signal is input to the PSA control unit 170 of the PSA device 40 until the PSA device 40 is stopped.

When it becomes necessary to stop the PSA device 40, such as during an inspection, a stop signal is input from a control unit (not shown) of the hydrogen production device 10 to the PSA control unit 170 of the PSA device 40.

When the stop signal is input, the PSA control unit 170 activates the stop control program.

Based on the stop control program, the PSA control unit 170 outputs a valve closing signal to the electromagnetic on-off valve 152 at the stop signal input timing (see FIG. 13, time T11) as shown in FIG. 13 (FIG. 12, step S102). (Hereinafter, "FIG. 12," is omitted). As a result, the electromagnetic on-off valve 152 is closed, and the hydrogen gas from the PSA device 40 (hydrogen gas storage tank 106, product hydrogen gas supply flow path 144) to the hydrogen gas user side via the hydrogen supply pipe 42 is released. The supply is stopped (see FIG. 14).

Subsequently, the PSA control unit 170 determines whether any of the first adsorption tower 102 and the second adsorption tower 104 is in the adsorption step (step S104). For example, the PSA control unit 170 determines based on whether or not either the electromagnetic on-off valve 114A or the electromagnetic on-off valve 114B is opened.

That is, if the electromagnetic on-off valve 114A is opened, it is determined that the first suction tower 102 is in the suction process, and if the electromagnetic on-off valve 114B is opened, it is determined that the second suction tower 104 is in the suction process. To do.

On the other hand, when both the electromagnetic on-off valves 114A and 114B are closed, it is determined that the pressure equalizing step is in progress (NO in step S104).

When either one of the first suction tower 102 and the second suction tower 104 is in the suction step (YES in step S104), the internal pressure of the suction tower during the suction step (detected value of the pressure sensor 162 or the pressure sensor 164). ) Is equal to or higher than the second threshold pressure Th2 (step S106). In the present embodiment, since the electromagnetic on-off valve 114A has been opened, it is determined whether or not the internal pressure of the first suction tower 102 is equal to or higher than the second threshold pressure Th2.

When the internal pressure of the first suction tower 102 is less than the second threshold pressure Th2 (NO in step S106), the rated operation is continued until the second threshold pressure Th2 is reached (excluding the electromagnetic on-off valve 152).

In this stop control, as described later, the first suction tower 102 and the second suction tower 104 are shut off from the outside to maintain the internal pressure so as to be equal to or higher than the predetermined pressure P0. The internal pressure of the adsorption tower on the adsorption process side is the second threshold pressure Th2 or more of the predetermined pressure P0 or more so that the internal pressure of the first adsorption tower 102 and the second adsorption tower 104 becomes the predetermined pressure P0 when compressed. Continue the adsorption process until it becomes.

The predetermined pressure P0 corresponds to the "first predetermined value".

Here, the second threshold pressure Th2 is, for example, 90% of the maximum value of the internal pressure of the suction tower during the pressure absorption step during the rated operation.

That is, when the internal pressure of the first suction tower 102 is less than the second threshold pressure Th2, the rated operation is continued.

On the other hand, when the internal pressure of the first suction tower 102 becomes the second threshold pressure Th2 or more (YES in step S106), the rated operation is stopped (see FIG. 13, time T12). Specifically, the electromagnetic on-off valves 114A and 132A are closed by outputting a valve closing signal, and the first adsorption tower 102, the raw material gas supply flow path 108, and the hydrogen gas storage tank 106 are shut off. Further, by outputting a valve closing signal to the electromagnetic on-off valve 120B to close the valve, the second suction tower 104 and the off-gas discharge flow path 116 are shut off (step S108).

That is, the first adsorption tower 102 and the second adsorption tower 104 are shielded from the outside.

At this time, when the electromagnetic on-off valves 138A and 138B that communicate the first suction tower 102 and the second suction tower 104 via the orifice 136 are opened, the valve closing signals are similarly sent to the electromagnetic on-off valves 138A and 138B. Is output to close the valve.

Subsequently, the PSA control unit 170 outputs a valve opening signal to the electromagnetic on-off valve for the pressure equalizing step (step S110). In the present embodiment, the electromagnetic on-off valves 124A, 124B, 142A, and 142B are opened to communicate the first suction tower 102 and the second suction tower 104. As a result, the pressures of the first suction tower 102, which was the suction step, and the second suction tower 104, which was the desorption step, are averaged (equalized) (see FIG. 15).

In the present embodiment, the pressure of the first suction tower 102 is brought to a second threshold pressure Th2 higher than the predetermined pressure P0 so as to be equal to or higher than the predetermined pressure P0 during the pressure equalization step, and then the first suction tower 102 and the first suction tower 102 and the first suction tower 102. 2 The suction tower 104 is shielded from the outside to equalize the pressure. Therefore, when the pressure is equalized, the first suction tower 102 and the second suction tower 104 can have a predetermined pressure P0 or more.

After performing the pressure equalizing step for a predetermined time, the PSA control unit 170 outputs a valve closing signal to the electromagnetic on-off valves 124A, 124B, 142A, 142B at time T13 (step S112).

At this timing, the PSA control unit 170 outputs a stop completion signal to the control unit of the hydrogen production apparatus 10 (step S114). The control unit of the hydrogen production apparatus 10 stops the operation of the reformer 20 and the compressor 30 by receiving the stop completion signal. That is, the supply of the reformed gas G5 to the PSA device 40 is stopped.

If it is determined in step S104 that neither the first adsorption tower 102 nor the second adsorption tower 104 is in the adsorption step (YES in step S104), it is considered that the pressure equalization step is in progress. Wait until the process is completed (NO in step S116).

When the processing time of the pressure equalizing step elapses (YES in step S116), the PSA control unit 170 outputs a valve closing signal to the electromagnetic on-off valves 124A, 124B, 142A, 142B, and ends the pressure equalizing step (step S112). ..

This state is maintained until the drive signal of the PSA device 40 is input to the PSA control unit 170. In other words, the deadline state of the first suction tower 102 and the second suction tower 104 is maintained until the PSA device 40 is restarted.

Further, when the PSA device 40 stopped in this way is restarted, the PSA control unit 170 outputs a valve opening signal to the electromagnetic on-off valve 114B, and the suction tower, which was in the attachment / detachment step immediately before the stop, In the present embodiment, the second suction tower 104 restarts the operation in the suction step (the first suction tower 102 is the desorption step).

This is because the second adsorption tower 104, which was in the desorption step immediately before the stop, was stopped in a state where impurities were removed, so that the impurities were less than those in the first adsorption tower 102, which was the adsorption step immediately before the stop. This is because the hydrogen purified in the first adsorption tower 102 by the pressure equalizing step is contained, and this hydrogen is used as the product hydrogen.

The PSA control unit 170 stores which adsorption tower was in the desorption step immediately before the stop.

(effect)
In this way, in the PSA device 40, when a stop signal is input during the rated operation, the electromagnetic on-off valve 152 is immediately closed to immediately stop the delivery of the product hydrogen gas to the hydrogen gas user side. it can.

Further, in the PSA device 40, the communication between the first adsorption tower 102 and the second adsorption tower 104 and the outside (raw material gas supply flow path 108, hydrogen gas storage tank 106, off gas discharge flow path 116) is cut off when the operation is stopped. Therefore, the internal pressures of the first suction tower 102 and the second suction tower 104 are maintained during the stoppage. That is, when the internal pressures of the first adsorption tower 102 and the second adsorption tower 104 decrease while the PSA device 40 is stopped, the impurities adhering to the adsorbents of the first adsorption tower 102 and the second adsorption tower 104 diffuse. , It is possible to prevent or suppress a long time (restart time) until the hydrogen gas having a predetermined purity is purified when the PSA apparatus 40 is restarted.

In particular, in the PSA device 40, when a stop signal is input during the rated operation, the rated operation (adsorption process / desorption) is performed until the adsorption tower during the adsorption process reaches the second threshold pressure Th2 or more unless the pressure equalization process is in progress. After continuing the step), each adsorption tower is shut off from the outside.

That is, in the PSA device 40, after raising the internal pressure of the suction tower during the suction step to the second threshold pressure Th2, each suction tower is shut off from the outside, so that the internal pressure of the suction tower is further increased during the stop. The state is maintained. As a result, impurities adhering to the adsorbent in the adsorption tower are suppressed from diffusing while the PSA device 40 is stopped.

The PSA device 40 opens the electromagnetic on-off valves 124A, 124B, 142A, and 142B after shutting off each suction tower from the outside, so that the first suction tower 102 and the second suction tower 104 are on the upstream side and the downstream side, respectively. The pressure is equalized by communicating with. As a result, the internal pressure of the adsorption tower on the desorption step side, which has a relatively low pressure, is increased, and the diffusion of impurities adhering to the adsorbent of the adsorption tower is further suppressed. That is, it is possible to shorten the time (restart time) until the impurities adhering to the adsorbent are removed when the PSA device 40 is restarted to purify the product hydrogen gas having a predetermined purity.

In particular, since the pressure of the first suction tower 102 that was in the suction step before the pressure equalization step is set to the second threshold pressure Th2 or more, which is a predetermined pressure P0 or more, the pressure equalization step is used to attach / detach the first suction tower 102 to the first suction tower 102. The second adsorption tower 104, which was inside, can be ensured to have a predetermined pressure P0 or higher, and the diffusion of impurities adhering to the adsorbent of the adsorption tower is further suppressed. That is, the restart time of the PSA device 40 can be further shortened.

Further, by moving the hydrogen gas purified in the first adsorption tower 102 to the second adsorption tower 104, the hydrogen gas storage tank 106 is transferred from the second adsorption tower 104, which is started in the adsorption step when the PSA device 40 is restarted. It can supply the transferred hydrogen. That is, the hydrogen purified in the first adsorption tower 102, which was the adsorption step when the PSA device 40 was stopped, can be used as a product without being discharged to the outside.

When the stop signal is input to the PSA device 40 during the pressure equalization process, the electromagnetic on-off valve 152 is immediately closed to immediately stop the delivery of the product hydrogen gas to the hydrogen gas user side. It operates until the end of the pressure equalizing process (or the adsorption process may be performed). That is, during the pressure equalization step, each adsorption tower is shielded from the outside and the internal pressure is maintained.

When the stop control is performed in this way, if the suction tower of the PSA device 40 is in the suction process, the rated operation is continued until the second threshold pressure Th2 is reached, and then each suction tower is shut off from the outside. Therefore, when the stop control is completed, the PSA device 40 outputs a stop completion signal to the control unit of the hydrogen production device 10. As a result, the reformer 20 and the compressor 30 of the hydrogen production apparatus 10 stop operating.

That is, when the rated operation is performed after the stop signal is input to the PSA device 40, the reformed gas is surely supplied to the PSA device 40 and the supply is surely stopped when it is no longer needed. Can be done.

In the hydrogen production apparatus 10, when the PSA apparatus 40 is stopped, after the stop signal is output to the PSA control unit 170 of the PSA apparatus 40, the reformer 20 and the reformer 20 are used until the stop completion signal is input from the PSA control unit 170. The operation of the compressor 30 is continued, and the reforming gas G5 can be supplied to the PSA device 40.

[Second Embodiment]
The PSA apparatus and the hydrogen production apparatus 200 according to the second embodiment of the present invention will be described with reference to FIGS. 16 to 18. The same reference numerals are given to the same components as those in the first embodiment, and detailed description thereof will be omitted. Further, since the PSA apparatus and the hydrogen production apparatus 200 have only changed a part of the stop control, only the configuration and the operation relating to the portion are described, and the detailed description of the operation and effect similar to that of the first embodiment is omitted. To do.

In the stop control, the pressure of the suction tower, for example, the first suction tower 102 during the suction step reaches the second threshold pressure Th2, and the electromagnetic on-off valve 114A communicates the first suction tower 102, the second suction tower 104 with the outside. , 132A and 120B are closed (see FIG. 16, step S108, hereinafter, “FIG. 16” is omitted) in the same manner as in the first embodiment.

After that, the PSA control unit 170 outputs a valve opening signal to the electromagnetic on-off valve 114B to open the electromagnetic on-off valve 114B (step S202). As a result, the reformed gas G5 is supplied from the connecting flow path pipe 64 to the second adsorption tower 104 via the raw material gas supply flow path 108. Since the second adsorption tower 102 does not communicate with any of the raw material gas supply flow paths 108, the pressure is increased.

The PSA control unit 170 compares the internal pressure of the second suction tower 104 with the second threshold pressure Th2 based on the detected value of the pressure sensor 162 (step S204).

When the pressure of the second suction tower 104 reaches the second threshold pressure Th2 (YES in step S204), a valve closing signal is output to the electromagnetic on-off valve 114B, and the electromagnetic on-off valve 114B is closed (step S206).

As a result, the PSA device 40 is stopped, and a stop completion signal is output to the control unit of the hydrogen production device 10 (step S114).

If any of the suction towers is not in the suction step (NO in step S104) at the timing when the stop signal is input to the PSA device 40, in the present embodiment, if the pressure equalization step is in progress, the pressure equalization step The rated operation is continued until one of the adsorption towers is in the adsorption process after the completion of.

(Other)
In the present embodiment, the PSA apparatus 40 is applied to the hydrogen production apparatus 10, and the PSA apparatus 40 purifies hydrogen from the reformed gas G5, but the present invention is not limited to this. It is applicable as long as the PSA device removes impurities from the raw material gas and purifies it into a purified gas.

Further, in the present embodiment, during the rated operation of the PSA device 40, the internal pressure in the suction tower during the suction step is monotonically increased, but it is conceivable that the pressure may decrease in the purging process or the like depending on the gas flow rate and the pipe diameter. .. When the internal pressure of the suction tower during the suction step drops below the second threshold pressure Th2 in the stop control of the present embodiment, the rated operation is performed until the internal pressure of the other suction tower reaches the second threshold pressure Th2. The control may be continuous.

Further, in the stop control of the second embodiment, after raising the internal pressure of the suction tower during the suction step to the second threshold pressure Th2, the internal pressure of the suction tower during the desorption step is raised to the second threshold pressure Th2. Although it is controlled, it may be controlled to increase the internal pressure by supplying the reforming gas to both adsorption towers at the same time as the stop signal is input.

Further, in the PSA device 40 of the present embodiment, the exhaust stop process is included in the rated operation, but the exhaust stop process may be omitted. That is, the pressure equalizing step may be controlled immediately after the purging step.

By the way, in the stop control of the first embodiment, the “end of rated operation” is the timing when the internal pressure of the first suction tower 102 reaches the second threshold pressure Th2 (see FIG. 13, time T12). Therefore, the subsequent pressure equalization step (see FIG. 13, times T12 to T13) is not included in the rated operation.

Further, also in the stop control of the second embodiment, the “end of rated operation” is the timing when the internal pressure of the first suction tower 102 reaches the second threshold pressure Th2 (see FIG. 17, time T12). Therefore, the subsequent step-up process of the second adsorption tower 104 (see FIG. 17, times T12 to T14) is not included in the rated operation.

Further, in the first embodiment or the second embodiment, the pressure equalizing step may be omitted when the PSA device 40 is stopped. In this case, at least the pressure of the suction tower during the suction stroke becomes the second threshold pressure Th2 or more. Therefore, during the shutdown period of the PSA apparatus 40, the pressure of the adsorption tower is maintained at a high state, and the diffusion of impurities in the adsorption tower is suppressed. Therefore, when the PSA device 40 is restarted, if the adsorption step of the adsorption tower that was in the adsorption process is restarted, the purity is relatively higher than that of the case where the adsorption process is restarted in another adsorption tower. High hydrogen gas will be supplied to the hydrogen gas storage tank 106, and the purity of the hydrogen gas stored in the hydrogen gas storage tank 106 will reach a predetermined purity as soon as possible. That is, the restart time of the PSA device 40 is shortened.

The second threshold pressure Th2, the predetermined pressure P0, and the like specified in the present embodiment are examples, and are not limited to these values.

Further, the PSA device 40 monitors the pressure of the pressure sensor 160 with the PSA control unit 170 during the pressure equalization process, so that when the pressure detected by the pressure sensor 160 becomes equal to or higher than the threshold pressure, the connecting flow path tube 64 The reforming gas may be vented to the outside of the hydrogen production apparatus 10.

10, 200 Hydrogen production equipment 20 Reformer 30 Compressor 40 PSA equipment 102 First adsorption tower 104 Second adsorption tower 106 Hydrogen gas storage tank (purified gas storage tank)
108 Raw material gas supply flow path 114A Electromagnetic on-off valve (pressure maintaining means)
114B electromagnetic on-off valve (pressure maintaining means)
116 Off-gas discharge flow path (off-gas flow path)
120A electromagnetic on-off valve (pressure maintenance means)
120B electromagnetic on-off valve (pressure maintenance means)
132A Electromagnetic on-off valve (pressure maintaining means)
132B Electromagnetic on-off valve (pressure maintaining means)
170 PSA control unit (pressure maintenance means)

Claims (14)

A plurality of adsorption towers filled with an adsorbent that adsorbs impurities in the raw material gas and sends out a purified gas from which impurities have been removed from the raw material gas.
A raw material gas supply flow path for supplying the raw material gas to the adsorption tower, and
A refined gas storage tank for storing the refined gas and
The off-gas flow path in which the off-gas containing the impurities is discharged from the adsorption tower, and the off-gas flow path.
While the device is stopped, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off, and the internal pressure of each of the adsorption towers is maintained at the first predetermined value or higher. Means and
A gas purification device equipped with. When the device is stopped, the pressure maintaining means continues the operation of the device until the internal pressure of some of the adsorption towers reaches a second predetermined value, and then the raw material gas supply flow path, the off-gas flow path, and the above. The gas purification apparatus according to claim 1, wherein the purification gas storage tank and each of the adsorption towers are shut off. The pressure maintaining means was an adsorption step immediately before the interruption, with the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers shut off when the apparatus was stopped. The gas purification apparatus according to claim 1 or 2, wherein at least a part of the adsorption towers and at least a part of the adsorption towers that were in the desorption step are communicated with each other. At least a part of the adsorption towers in the adsorption step is each adsorption tower in the adsorption step, and at least a part of the adsorption towers in the desorption step is in each adsorption tower in the desorption step. The gas purification apparatus according to claim 3. When the apparatus is stopped, the pressure maintaining means shuts off at least a part of the adsorption tower, which was the adsorption step, from the raw material gas supply flow path, the off gas flow path, the refined gas storage tank, or the raw material gas supply flow. After supplying the raw material gas from the path to the adsorption tower and supplying the raw material gas from the raw material gas supply flow path to at least a part of the adsorption towers in the desorption step, the raw material gas supply flow path and the off gas The gas purification apparatus according to claim 1 or 2, which shuts off the flow path, the refined gas storage tank, and each of the adsorption towers. The gas purification apparatus according to claim 5, wherein at least a part of the adsorption towers in the desorption step is each adsorption tower in the desorption step. A reformer that produces a reformed gas obtained by steam reforming hydrocarbons,
A compressor that compresses the reformed gas and
The gas purification according to any one of claims 1 to 6, wherein the reformed gas compressed by the compressor is used as the raw material gas, and impurities are separated from the reformed gas to obtain hydrogen gas as the refined gas. With the device
A hydrogen production device equipped with. When the gas purification apparatus is stopped, the reformer and the compressor continue to operate until the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank and each of the adsorption towers are shut off. The hydrogen production apparatus according to claim 7. Purification by supplying the raw material gas from the raw material gas supply flow path to a part of the adsorption towers among the plurality of adsorption towers, adsorbing the impurities on the adsorbent filled in the adsorption tower, and removing the impurities from the raw material gas. In a gas purification device that sends gas to a refined gas storage tank and discharges off-gas containing impurities from an adsorbent filled inside some of the other adsorbent towers to the off-gas flow path. ,
While the gas purification apparatus is stopped, the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank, and each of the adsorption towers are shut off, and the internal pressure of each adsorption tower is set to the first predetermined value or more. How to control the gas refinery to maintain. When the gas purification apparatus is stopped, the operation of the apparatus is continued until the internal pressure of some of the adsorption towers reaches the second predetermined value, and then the raw material gas supply flow path, the off-gas flow path, and the refined gas storage are performed. The method for controlling a gas purification apparatus according to claim 9, wherein the tank and each of the adsorption towers are shut off. When the gas purification apparatus was stopped, at least a part of the adsorption step was performed immediately before the interruption in a state where the raw material gas supply flow path, the off-gas flow path, the refined gas storage tank and each of the adsorption towers were shut off. The method for controlling a gas purification apparatus according to claim 9 or 10, wherein the adsorption tower of the above is communicated with at least a part of the adsorption towers in the desorption step. At least a part of the adsorption towers in the adsorption step is each adsorption tower in the adsorption step, and at least a part of the adsorption towers in the desorption step is in each adsorption tower in the desorption step. The control method of the gas purification apparatus according to claim 11. When the gas purification apparatus is stopped, at least a part of the adsorption tower that was the adsorption step is shut off from the raw material gas supply flow path, the off gas flow path, the refined gas storage tank, or from the raw material gas supply flow path. After supplying the raw material gas to the adsorption tower and supplying the raw material gas from the raw material gas supply flow path to at least a part of the adsorption towers in the desorption step, the raw material gas supply flow path and the off gas flow path. The method for controlling a gas purification apparatus according to claim 9 or 10, wherein the refined gas storage tank and each of the adsorption towers are shut off. The method for controlling a gas purification apparatus according to claim 13, wherein at least a part of the adsorption towers in the desorption step is each adsorption tower in the desorption step.