JP6937087B2 - Gas purification equipment and its control method, and hydrogen production equipment - Google Patents

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 a gas purifier that removes impurities from a raw material gas and purifies it into 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 to be separated and purified into hydrogen gas.

Patent Document 1 proposes a hydrogen production apparatus including 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 be restarted after being stopped for inspection or the like. In this case, impurities adhering to the adsorbent diffuse inside the adsorption tower while the operation of the PSA device is stopped. As a result, when the PSA apparatus is started, it takes time for the purified gas purified in the adsorption tower to reach a predetermined purity.

Therefore, it is desired to shorten the time required for the purified gas to reach a predetermined purity when the PSA apparatus is started.

An object of the present invention is to provide a gas purification apparatus, a control method thereof, and a hydrogen production apparatus that shorten the time required for the refined gas to reach a predetermined purity at the start of the gas purification apparatus.

The gas purification apparatus according to claim 1 is filled with an adsorbent that adsorbs impurities in the raw material gas, and has a plurality of adsorption towers that send out a purified gas from which the impurities have been removed from the raw material gas, and purification that stores the purified gas. During the start-up operation period of the gas storage tank and the apparatus, the communication between each of the adsorption towers and the refined gas storage tank is cut off, and during the start-up operation period, the adsorption tower during the adsorption process is purified to the adsorption tower during the desorption process. A control means for supplying gas and a plurality of pressure detecting means for detecting the pressure of each of the adsorption towers are provided , and the control means of each of the adsorption towers during the adsorption step within a set time of the adsorption step. When the pressure does not reach the threshold pressure, the suction step of the suction tower and the desorption step are switched when the set time elapses, and the pressure of each suction tower in the suction step reaches the threshold pressure within the set time. When it reaches, the adsorption step and the desorption step of the suction tower are switched when the threshold pressure is reached .

In this gas purification apparatus, impurities adhering to the adsorbent inside the adsorption tower diffuse during the shutdown period of the apparatus. Therefore, it takes time for the purity of the purified gas purified in the adsorption tower to reach a predetermined quality during the start-up operation of the gas purification apparatus. Since the refined gas purified during that period has not reached a predetermined purity, it cannot be stored in the refined gas storage tank as a refined gas.

Therefore, during the start-up operation period of the gas purification device, the communication between the adsorption tower and the refined gas storage tank is cut off to prevent the refined gas that does not reach a predetermined purity from being stored in the refined gas storage tank.

In addition, by communicating the adsorption tower during the adsorption process and the adsorption tower during the desorption process during the start-up operation period of the gas purification device, the purified gas is supplied to the adsorption tower during the desorption process from the adsorption tower during the adsorption process. , It is possible to promote the removal of impurities from the adsorbent in the adsorption tower during the desorption step. As a result, the time required for removing impurities in the adsorption tower is shortened.

That is, the start-up operation period of the gas purification device, that is, the time until the refined gas delivered from the adsorption tower reaches a predetermined purity is shortened.

In this gas purification device, if the pressure of each adsorption tower during the adsorption process reaches the threshold pressure within the set time of the adsorption process, the adsorption process and the desorption process of the adsorption tower are switched when the threshold pressure is reached, resulting in wasted time. Can be prevented from occurring.

Further, in this gas purification apparatus, if the pressure of each adsorption tower during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower are switched after the set time elapses. As a result, it is possible to prevent the suction step and the desorption step from taking a long time when the pressure rise rate of the suction tower during the suction step is low.

As a result, the gas purification apparatus can efficiently switch between the adsorption step and the desorption step of each adsorption tower during the start-up operation period. That is, the start-up time of the gas purification apparatus can be shortened, and the productivity of the refined gas that has reached a predetermined purity can be improved.

The gas purification apparatus according to claim 2 is filled with an adsorbent that adsorbs impurities in the raw material gas, and has a plurality of adsorption towers that send out purified gas from which impurities have been removed from the raw material gas, and purification that stores the purified gas. During the start-up operation period of the gas storage tank and the apparatus, the communication between each of the adsorption towers and the refined gas storage tank is cut off, and during the start-up operation period, the adsorption tower during the adsorption process is purified to the adsorption tower during the desorption process. A control means for supplying gas and a plurality of pressure detecting means for detecting the pressure of each of the adsorption towers are provided, and the control means of each of the adsorption towers during the adsorption step within a set time of the adsorption step. When the pressure does not reach the threshold pressure, the suction step of the suction tower and the desorption step of the suction tower are switched with the pressure equalizing step in between, and each suction tower in the suction step is switched within the set time. When the pressure reaches the threshold pressure, the adsorption step and the desorption step of the suction tower are switched with the pressure equalization step in between when the threshold pressure is reached .

In this gas purification device, if the pressure of each adsorption tower during the adsorption step reaches the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower are sandwiched between the pressure equalization steps when the threshold pressure is reached. By switching, it is possible to prevent wasted time.

On the other hand, in this gas purification apparatus, if the pressure of each adsorption tower during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower are equalized after the set time elapses. Switch across the process. As a result, it is possible to prevent the suction step and the desorption step from taking a long time when the pressure rise rate of the suction tower during the suction step is low.

As a result, the gas purification apparatus can efficiently switch between the adsorption step of each adsorption tower and the pressure equalizing step of the desorption step during the start-up operation period. That is, the start-up time of the gas purification apparatus can be shortened, and the productivity of the refined gas that has reached a predetermined purity can be improved.

By sandwiching the pressure equalizing step between the adsorption step and the desorption step, the pressure rise of the adsorption tower, which was the desorption step before the pressure equalization step, is expedited, and the adsorption tower, which was the adsorption step before the pressure equalization step, is purified. The gas can be moved to the adsorption tower which was the desorption step, and the adsorption tower which was the desorption step can use the purified gas for the next application in the next adsorption step.
The gas purification apparatus according to claim 3 is the gas purification apparatus according to claim 1 or 2, wherein the control means maintains a state in which communication between the adsorption tower and the purification gas storage tank is cut off during the start-up operation period. With the gas remaining, each of the adsorption towers is allowed to perform the adsorption step and the desorption step at least once.

The hydrogen production apparatus according to claim 4 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 3 , 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 product hydrogen gas purified from the adsorption tower in the adsorption step is stored in the refined gas storage tank.

Further, in the gas purification device, as described above, during the start-up operation period of the gas purification device, the communication between the adsorption tower and the refined gas storage tank is cut off, and during the start-up operation period, the adsorption step is desorbed from the adsorption tower. Impurities are removed from the adsorption tower by supplying purified hydrogen gas that has not reached the predetermined purity to the adsorption tower. That is, the start-up operation period of the gas purification device, that is, the time until the hydrogen gas reaches a predetermined purity can be shortened, and the hydrogen gas that has not reached the predetermined purity is stored in the hydrogen gas storage tank. Can be prevented.

In the control method of the gas purification apparatus according to claim 5 , the raw material gas is supplied to a part of the adsorption towers among the plurality of adsorption towers, and impurities are adsorbed on the adsorbent filled in the adsorption towers to adsorb the raw materials. In the gas purification device that sends the purified gas from which impurities are removed from the gas to the refined gas storage tank, the communication between each of the adsorption towers and the refined gas storage tank is cut off during the start-up operation period of the gas purification device, and the above-mentioned It is a control method of a gas purification device that supplies purified gas from the adsorption tower in the adsorption process to the adsorption tower in the desorption process during the start-up operation period. When the pressure does not reach the threshold pressure, the suction step of the suction tower and the desorption step are switched when the set time elapses, and the pressure of each suction tower in the suction step reaches the threshold pressure within the set time. When it reaches, the adsorption step and the desorption step of the suction tower are switched when the threshold pressure is reached .

In the control method of this gas purification device, by blocking the communication between the adsorption tower and the refined gas storage tank during the start-up operation period, the refined gas that does not reach the predetermined purity is stored in the refined gas storage tank as the refined gas. To prevent.

On the other hand, during the start-up operation period of the gas purification device, the adsorption tower in the adsorption process and the adsorption tower in the desorption process are communicated with each other to supply the purified gas from the adsorption tower in the adsorption process to the adsorption tower in the desorption process. , It is possible to promote the removal of impurities in the adsorption tower during the desorption step. As a result, the time required for removing impurities in the adsorption tower is shortened.

As a result, the start-up operation period of the gas purification apparatus, that is, the time until the refined gas delivered from the adsorption tower reaches a predetermined purity is shortened.

In the control method of this gas purification device, if the pressure of each adsorption tower during the adsorption step reaches the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower are switched when the threshold pressure is reached. , It is possible to prevent wasted time.

On the other hand, in the control method of this gas purification apparatus, if the pressure of each adsorption tower during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower after the set time elapses. To switch. As a result, it is possible to prevent the suction step and the desorption step from taking a long time when the pressure rise rate of the suction tower during the suction step is low.

As a result, in the control method of the gas purification apparatus, it is possible to efficiently switch between the adsorption step and the desorption step of each adsorption tower during the start-up operation period. That is, the start-up operation period of the gas purification device can be shortened, and the productivity of the refined gas that has reached a predetermined purity can be improved.

The control method of the gas purification apparatus according to claim 6 is to supply the raw material gas to a part of the suction towers among the plurality of suction towers and adsorb impurities to the adsorbent filled in the suction towers to adsorb the raw materials. In a gas refining device that sends a refined gas from which impurities have been removed from the gas to a refined gas storage tank, the communication between each of the adsorption towers and the refined gas storage tank is cut off during the start-up operation period of the gas purification device, and the above-mentioned It is a control method of a gas purification device that supplies purified gas from the adsorption tower in the adsorption process to the adsorption tower in the desorption process during the start-up operation period. When the pressure does not reach the threshold pressure, the suction step of the suction tower and the desorption step of the suction tower are switched with the pressure equalizing step in between, and each suction tower in the suction step is switched within the set time. When the pressure reaches the threshold pressure, the adsorption step and the desorption step of the suction tower are switched with the pressure equalization step in between when the threshold pressure is reached .

In the control method of this gas purification device, if the pressure of each adsorption tower in the adsorption step reaches the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower are subjected to the pressure equalization step when the threshold pressure is reached. It is possible to prevent wasted time by switching between the two.

On the other hand, in the control method of this gas purification apparatus, if the pressure of each adsorption tower during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the adsorption step and the desorption step of the adsorption tower after the set time elapses. Is switched across the pressure equalizing process. As a result, it is possible to prevent the suction step and the desorption step from taking a long time when the pressure rise rate of the suction tower during the suction step is low.

As a result, in this control method of the gas purification apparatus, it is possible to efficiently switch between the adsorption step of each adsorption tower and the pressure equalizing step of the desorption step during the start-up operation period. That is, the start-up time of the gas purification apparatus can be shortened, and the productivity of the refined gas that has reached a predetermined purity can be improved.

By sandwiching the pressure equalizing step between the adsorption step and the desorption step, the pressure rise of the adsorption tower, which was the desorption step before the pressure equalization step, is expedited, and the adsorption tower, which was the adsorption step before the pressure equalization step, is purified. The gas can be moved to the adsorption tower which was the desorption step, and the adsorption tower which was the desorption step can use the purified gas for the next application in the next adsorption step.
The method for controlling the gas purification device according to claim 7 is the control method for the gas purification device according to claim 5 or 6, wherein in the gas purification device, each of the adsorption tower and the refined gas storage tank is used during the start-up operation period. Each of the adsorption towers is allowed to perform the adsorption step and the desorption step at least once while maintaining the state in which the communication is cut off.

Since the gas purification apparatus according to the invention according to claims 1 to 3 has the above configuration, the start-up operation period of the gas purification apparatus, that is, the time until the purified gas reaches a predetermined purity can be shortened.

Since the hydrogen production apparatus according to the fourth aspect of the invention has the above configuration, the start-up operation period of the gas purification apparatus, that is, the time until the hydrogen gas reaches a predetermined purity can be shortened.

Since the control method of the gas purification device according to the invention according to claims 5 to 7 has the above configuration, the start-up operation period of the gas purification device, that is, the time until the purified gas reaches a predetermined purity can be shortened.

It is a schematic block diagram which showed the hydrogen production apparatus which concerns on one Embodiment. It is a schematic block diagram which showed the PSA apparatus which concerns on one Embodiment. It is a block diagram which showed the hardware composition of the PSA apparatus which concerns on one Embodiment. It is a block diagram which showed the hardware structure of the PSA control part which concerns on one Embodiment. It is a figure which shows the timing chart of the switching control of the electromagnetic on-off valve of the rated operation of the PSA apparatus which concerns on one 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 of the rated operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the hydrogen delivery process of the rated operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the open / closed state of the electromagnetic on-off valve in the purging process of the rated operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the exhaust stop process of the rated operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the pressure equalizing process of the rated operation of the PSA apparatus which concerns on one 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 in the rated operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the timing chart of the switching control of the electromagnetic on-off valve of the start-up operation of the PSA apparatus which concerns on one 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 of the start-up operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the purging process of the start-up operation of the PSA apparatus which concerns on one Embodiment. It is a figure which shows the opening and closing state of the electromagnetic on-off valve in the pressure equalizing step of the start-up operation of the PSA apparatus which concerns on one 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 in the start-up operation of the PSA apparatus which concerns on one Embodiment.

A PSA apparatus according to an embodiment and a hydrogen production apparatus to which the PSA apparatus is applied will be described with reference to FIGS. 1 to 16.

<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.

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 sent to 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 separating unit 50, the compressor 30, the post-pressurizing water separating 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 reforming gas G3 from the pre-boost water separation unit 50 flows, and a reforming gas G4 in which the reforming 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 unit 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 reformed 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 (gas) is delivered, and the like. It is connected to the upstream end of the off-gas supply pipe 44 to which the off-gas separated by the PSA device 40 is delivered. 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. be.

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 dissolved ion components. 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”.

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 having one end connected to a connecting flow path pipe 64 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. 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 communication flow path 122, and the common flow path 112B.

A pair of electromagnetic on-off valves 124A and 124B are arranged on the communication 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 configured to be 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 shut 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 sensors 162 and 164 correspond to "pressure detecting means".

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 the electromagnetic on-off valves 114A to 152 are controlled to open and close based on the detected values of the pressure sensors 162 and 164 according to a control program described later. Is what you do.

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

Next, 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 another device.

(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, water condensed by cooling by heat exchange in the heat exchanger HE1 is stored 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 from 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-pressurization 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, the 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 reforming 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 indicates 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 by the control signal from the PSA control unit 170, and the communication flow path pipe 64 passes through the raw material gas supply flow path 108. 1 The reforming gas G5 is supplied to the adsorption tower 102. 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).

Since it is clear that the electromagnetic on-off valve is opened and closed based on the control signal from the PSA control unit 170, the following description of opening and closing the electromagnetic on-off valve is described as "based on the control signal from the PSA control unit 170". Is omitted.

Further, at time T0, the electromagnetic on-off valve 120B is opened, and the second suction tower 104 communicates 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, 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, and 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. NS.

Hereinafter, as with 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, the PSA device 40 has a threshold pressure Th1 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 period. ..

This is because the check valve 156 is opened when the pressures of the first suction tower 102 and the second suction tower 104 are higher than the 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 (hydrogen is vented).

Therefore, in the PSA control unit 170, in the rated operation and the start-up operation described later, switching of the suction step, the desorption step, the pressure equalizing step, etc. is basically performed based on the set time, but the first suction tower 102 and the second suction tower 102 and the second suction. When the pressure of the tower 104 (detected value of the pressure sensors 162 and 164) reaches the threshold pressure Th1 within the set time, the pressure of the first suction tower 102 and the second suction tower 104 is immediately switched between the suction step and the desorption step. Is configured to prevent hydrogen from being vented from the vent flow path 154 of the PSA device 40 via the vent pipe 45 beyond the threshold pressure Th1. When the pressure equalizing step is sandwiched between the adsorption step and the desorption step as in the present embodiment, the structure is such that the adsorption step or the desorption step is immediately shifted to the pressure equalizing step.

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.

(Startup operation)
Next, the case of activating the PSA device 40 will be described with reference to FIGS. 12 to 16.

At this time, a start signal is input to the PSA control unit 170 from a control unit (not shown) of the hydrogen production apparatus 10.

When the start-up signal is input, the PSA control unit 170 reads the start-up operation control program from the storage 178 and executes it to control the opening and closing of the electromagnetic on-off valves 114A to 152, and the start-up operation is performed. The “start-up operation of the PSA device” refers to the operation of the PSA device 40 from the start of the start-up of the PSA device 40 until at least hydrogen gas of a predetermined purity can be delivered from each adsorption tower.

The PSA control unit 170 controls based on the time control in the same manner as the rated operation according to the start-up operation control program. However, by keeping the electromagnetic on-off valves 132A and 132B closed during the start-up operation period, it is possible to prevent hydrogen gas that has not reached a predetermined purity from being stored in the hydrogen gas storage tank 106. .. Therefore, the hydrogen delivery process in the adsorption process of the rated operation is omitted. In the time control, the set time of each process is the same as the rated operation.

Further, in the PSA apparatus 40 of the present embodiment, as the start-up operation, the first suction tower 102 and the second suction tower 104 perform the suction step and the desorption step once, respectively, and then shift to the rated operation.

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. Will be done.

The PSA control unit 170 stores the suction tower that was in the desorption step immediately before the end of the operation of the PSA device 40, and is activated so that the suction tower starts in the suction step.

In the present embodiment, the first adsorption tower 102 is started in the adsorption step, and the second adsorption tower 104 is started in the desorption step. 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. 12 and 13, first, at time T11, 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 T11, the electromagnetic on-off valve 120B is opened, and the second suction tower 104 communicates 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.

Next, as shown in FIGS. 12 and 14, the electromagnetic on-off valves 138A and 138B are opened at the time T12 after a predetermined time has elapsed from the time T11. 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).

In the rated operation, as shown in FIGS. 5 and 7, when the pressure in the first suction tower 102 rises sufficiently (at time T1), the electromagnetic on-off valve 132A is opened and the first suction is performed. A hydrogen delivery process of supplying the purified hydrogen gas purified in the tower 102 to the hydrogen gas storage tank 106 is performed, but during the start-up operation period, as shown in FIG. 12, the closed state of the electromagnetic on-off valve 132A is maintained. The hydrogen delivery process is omitted.

This is because during the start-up operation period, impurities are diffused inside the adsorbent in the adsorption tower while the operation of the PSA device 40 is stopped, and the purity of the purified hydrogen gas does not reach a predetermined purity. ..

Further, during the start-up operation of the PSA device 40, the electromagnetic on-off valve 152 is always closed and is not supplied to the hydrogen gas user side via the hydrogen supply pipe 42.

By the way, during the purging process, unlike the rated operation, the electromagnetic on-off valve 132A is closed, so that the purified hydrogen gas sent from the first adsorption tower 102 is supplied to the hydrogen gas storage tank 106. Therefore, the pressure rise rate of the first suction tower 102 is high. Therefore, the pressure of the first adsorption tower 102 reaches the threshold pressure Th1 at time T13 before reaching the set time of the purging process set in the program (see FIG. 12).

When the PSA control unit 170 detects that the pressure of the first suction tower 102 reaches the threshold pressure Th1 within the set time Ts2 of the suction process of the start-up operation based on the detection result of the pressure sensor 162, the first suction tower 102 The adsorption step of No. 1 and the desorption step of the second adsorption tower 104 are immediately completed, and the process shifts to the pressure equalization step. In the present embodiment, the set time Ts2 of the adsorption process of the start-up operation is the time obtained by subtracting the hydrogen delivery process from the set time Ts1 (= T4-T0, see FIG. 5) of the adsorption process of the rated operation (Ts2). = Ts1- (T2-T1), see FIGS. 5 and 12).

Specifically, as shown in FIGS. 12 and 15, the electromagnetic on-off valves 114A, 138A, and 138B are closed at time T13. As a result, the first adsorption tower 102 is cut off from the raw material gas supply flow path 108 and is cut off from the orifice 136. As a result, the reforming gas is not supplied to the first adsorption tower 102.

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, as shown in FIG. 15, 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, and 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 pressures of the first suction tower 102 and the second suction tower 104 are 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. 12 and 16, at the time T14 after a predetermined time elapses from the time T13, 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 (the pressure equalizing step is completed).

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. That is, the adsorption step is started in the second adsorption tower 104.

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. NS. That is, the desorption step is started in the first adsorption tower 102.

Hereinafter, as with the timing from time T11 to time T14, the opening / closing control of the electromagnetic on-off valve is performed at the timing from time T14 to time T17, 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.

In this way, the start-up operation is completed when all the adsorption towers of the PSA apparatus 40, that is, the first adsorption tower 102 and the second adsorption tower 104 perform the adsorption step and the desorption step once, that is, once in one cycle. Hereinafter, the rated operation is carried out.

This is because the impurities diffused in the adsorbent are sufficiently removed in the first adsorption tower 102 and the second adsorption tower 104, and the hydrogen gas produced by purifying the reforming gas reaches a predetermined purity. It is determined that the gas has been discharged and sent to the hydrogen gas storage tank 106.

That is, hydrogen purified by the first adsorption tower 102 or the second adsorption tower 104 by opening the electromagnetic on-off valve 132A or the electromagnetic on-off valve 132B in the hydrogen delivery process or the purging process of the adsorption process of the rated operation. Since the gas is sent to the hydrogen gas storage tank 106, the pressure rise rate of the adsorption tower is suppressed. Therefore, the set time Ts1 (= T4-T0) of the suction step of the rated operation elapses before the pressure of the first suction tower 102 or the second suction tower 104 reaches the threshold pressure Th1, and when the set time elapses (for example, for example). It is possible to switch to the next step (pressure equalizing step) (at time T21).

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

(effect)
As described above, when the start signal is input, the PSA device 40 has the following effects by performing an operation different from the rated operation (rated operation control program) according to the start operation control program.

First, by maintaining the closed state of the electromagnetic on-off valves 132A and 132B during the start-up operation period (referred to as “deadline operation”), purified hydrogen gas is supplied from the adsorption tower in the adsorption process to the hydrogen gas storage tank 106. Is prevented. That is, it is possible to reliably prevent hydrogen gas that has not reached a predetermined purity during the start-up operation period from being sent to the hydrogen gas storage tank 106 and being supplied to the hydrogen gas user side.

Further, by performing the purging process during the start-up operation period, the adsorption tower (for example, the adsorption tower 102) during the adsorption step desorbs the hydrogen gas that has not reached the predetermined purity purified by the adsorption tower (for example, the first adsorption tower 102). For example, by supplying it to the second adsorption tower 104), it can be used for purging the adsorption tower during the desorption step. As a result, it is possible to promote the removal of impurities from the adsorbent in the adsorption tower and shorten the time for the hydrogen gas purified in the adsorption tower to reach a predetermined purity. Further, by using hydrogen gas that has not reached a predetermined purity in the purging process, it can be effectively used.

Further, during the start-up operation period, both the first adsorption tower 102 and the second adsorption tower 104 perform the adsorption step and the desorption step at least once (perform at least one cycle), so that each adsorption tower is performed at least once. Since the desorption step is performed, impurities diffused inside the adsorbent of each adsorption tower are removed during the stoppage, and the purity of the purified hydrogen gas can be rapidly improved to a predetermined purity.

Further, by performing the deadline operation during the start-up operation period, the pressure rise rate of the suction tower (for example, the first suction tower 102) during the suction process becomes higher than that of the rated operation, and the threshold value is within the set time of the purge process. When the pressure Th1 is reached, the purging process (adsorption process) is completed, and the pressure equalization process is immediately switched to. That is, the adsorption process (desorption process) time in the start-up operation is shortened as compared with the rated operation. That is, the switching cycle between the adsorption step and the desorption step in the start-up operation is shortened as compared with the rated operation, and the time until the purified hydrogen reaches a predetermined purity is shortened.

Furthermore, since the start-up operation omits the hydrogen delivery process of the rated operation, the purging process can be sufficiently performed even if the adsorption process time is shortened as compared with the rated operation, and the adsorption tower during the desorption process can be sufficiently performed. Impurities diffused in the adsorbent can be sufficiently removed.

Further, the PSA control unit 170 stores the adsorption tower that was the attachment / detachment step immediately before the PSA device 40 was stopped, and starts from the adsorption step of the adsorption tower at the start of the start-up operation. As a result, hydrogen gas purified by the adsorption tower, which was the desorption step immediately before the stop, is supplied to the adsorption tower, which was the adsorption step immediately before the stop, and is purged. That is, at the start of the start-up operation, hydrogen gas having a higher purity is supplied to the adsorption tower during the desorption step, and the removal of impurities is promoted.

Further, 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, respectively. The pressure is equalized by communicating on the downstream side. As a result, the 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 suppressed. That is, the start-up operation period of the PSA device 40, that is, the time required to remove impurities adhering to the adsorbent and purify the product hydrogen gas having a predetermined purity can be shortened.

(others)
In the present embodiment, the PSA device 40 is applied to the hydrogen production device 10, and the PSA device 40 purifies hydrogen (gas) 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 refined gas.

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.

Further, in the PSA device 40 of the present embodiment, the start-up operation is controlled to be performed only for one cycle of each adsorption tower, but it may be carried out for two or more cycles.

Further, in the PSA apparatus 40 of the present embodiment, the hydrogen delivery process (time) of the rated operation is omitted by controlling so that the boosting process is followed by the purging process in the adsorption process of the start-up operation. The pressurization process may be extended. In this case, it is desirable that the pressure of the adsorption tower during the adsorption step does not reach the threshold pressure (Th1) before reaching the purge process. When the desorption step is completed without the adsorption tower in the desorption step going through the purging process, the removal of impurities in the adsorbent does not proceed, and the time until the purity of the hydrogen gas purified in each adsorption tower reaches a predetermined purity. This is because there is a risk that it will take a long time.

In this case, the set time Ts2 of the adsorption process in the start-up operation is equal to the set time Ts1 of the adsorption process in the rated operation (see FIG. 5, Ts2 = Ts1 = T4-T0).

Further, in the PSA apparatus 40 of the present embodiment, the pressure equalizing step is inserted between the adsorption step and the desorption step, but the PSA apparatus 40 may not have the pressure equalizing step. In this case, if the pressure of the suction tower reaches the threshold pressure Th1 within the set time Ts of the suction step during the start-up operation period, the suction step is directly switched to the desorption step when the threshold pressure is reached.

Further, the PSA device 40 of the present embodiment has a configuration having two suction towers, a first suction tower 102 and a second suction tower 104, but may have three or more suction towers.

Further, although the PSA device 40 of the present embodiment has a start-up operation program and a rated operation program as separate programs, a single operation program may have, for example, a start-up operation subroutine.

Further, in the PSA apparatus 40 of the present embodiment, the case where the pressures of the first suction tower 102 and the second suction tower 104 reach the threshold pressure Th1 within the set time Ts2 of the suction step during the start-up operation period has been described. It may be a configuration that does not reach. In this case, the adsorption step (desorption step) of the first suction tower 102 and the second suction tower 104 is switched to the pressure equalization step when the set time Ts2 of the suction step elapses, and the desorption step is performed after the set time of the pressure equalization step elapses. (Adsorption process).

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 communication flow path tube 64 The reforming gas may be vented to the outside of the hydrogen production apparatus 10.

10 Hydrogen production equipment 20 Reformer 30 Compressor 40 PSA equipment (gas purification equipment)
102 First adsorption tower 104 Second adsorption tower 106 Hydrogen gas storage tank (refined gas storage tank)
108 Raw material gas supply flow path 114A Electromagnetic on-off valve (control means)
114B electromagnetic on-off valve (control means)
116 Off-gas discharge flow path (off-gas flow path)
120A electromagnetic on-off valve (control means)
120B electromagnetic on-off valve (control means)
132A electromagnetic on-off valve (control means)
132B electromagnetic on-off valve (control means)
162 Pressure sensor (pressure detecting means)
164 Pressure sensor (pressure detecting means)
170 PSA control unit (control means)

Claims (7)

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 refined gas storage tank for storing the refined gas and
During the start-up operation period of the device, the communication between each of the adsorption towers and the refined gas storage tank is cut off, and the refined gas is supplied from the adsorption tower during the start-up operation to the adsorption tower during the desorption process during the start-up operation period. Means and
A plurality of pressure detecting means for detecting the pressure of each of the suction towers,
Equipped with a,
If the pressure of each of the adsorption towers during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the control means will perform the adsorption step and the desorption step of the adsorption tower when the set time elapses. A gas purification device that switches between the adsorption step and the desorption step of the adsorption tower when the pressure of each adsorption tower in the adsorption step reaches the threshold pressure within the set time. 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 refined gas storage tank for storing the refined gas and
During the start-up operation period of the device, the communication between each of the adsorption towers and the refined gas storage tank is cut off, and the refined gas is supplied from the adsorption tower during the start-up operation to the adsorption tower during the desorption process during the start-up operation period. Means and
A plurality of pressure detecting means for detecting the pressure of each of the suction towers,
With
If the pressure of each of the adsorption towers during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the control means will perform the adsorption step and the desorption step of the adsorption tower when the set time elapses. When the pressure of each adsorption tower in the adsorption step reaches the threshold pressure within the set time, the adsorption step and the desorption step of the adsorption tower are performed when the threshold pressure is reached. A gas purification device that switches between the above pressure equalization steps. The claim means that the control means causes each of the adsorption towers to perform an adsorption step and a desorption step at least once while maintaining a state in which communication between the adsorption tower and the refined gas storage tank is cut off during the start-up operation period. The gas purification apparatus according to 1 or 2. A reformer that produces a reformed gas obtained by steam reforming hydrocarbons,
A compressor that compresses the reformed gas and
The gas purification apparatus according to any one of claims 1 to 3, wherein the reforming gas compressed by the compressor is used as the raw material gas, and impurities are separated from the reforming gas to obtain hydrogen gas as the purification gas. When,
A hydrogen production device equipped with. A refined gas storage tank in which raw material gas is supplied to a part of the adsorption towers among the plurality of adsorption towers, impurities are adsorbed on the adsorbent filled in the adsorption towers, and impurities are removed from the raw material gas. In the gas purification equipment to be sent to
During the start-up operation period of the gas purification device, the communication between each of the adsorption towers and the refined gas storage tank is cut off, and the refined gas is transferred from the adsorption tower during the adsorption step to the adsorption tower during the desorption step during the start-up operation period. It is a control method of the gas refining device that supplies
If the pressure of each adsorption tower during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the adsorption step of the adsorption tower and the desorption step are switched when the set time elapses, and the setting is performed. A method for controlling a gas purification device that switches between the adsorption step and the desorption step of the adsorption tower when the pressure of each adsorption tower in the adsorption step reaches the threshold pressure within an hour. A refined gas storage tank in which raw material gas is supplied to a part of the adsorption towers among the plurality of adsorption towers, impurities are adsorbed on the adsorbent filled in the adsorption towers, and impurities are removed from the raw material gas. In the gas purification equipment to be sent to
During the start-up operation period of the gas purification device, the communication between each of the adsorption towers and the refined gas storage tank is cut off, and the refined gas is transferred from the adsorption tower during the adsorption step to the adsorption tower during the desorption step during the start-up operation period. It is a control method of the gas refining device that supplies
If the pressure of each adsorption tower during the adsorption step does not reach the threshold pressure within the set time of the adsorption step, the pressure equalizing step is sandwiched between the adsorption step and the desorption step of the adsorption tower when the set time elapses. If the pressure of each suction tower in the suction step reaches the threshold pressure within the set time, the suction step of the suction tower and the desorption step are performed in the pressure equalizing step when the threshold pressure is reached. A method of controlling a gas purification device that switches between sandwiches. A request for each of the adsorption towers to perform an adsorption step and a desorption step at least once while maintaining a state in which communication between the adsorption tower and the refined gas storage tank is cut off during the start-up operation period of the gas purification apparatus. Item 5. The method for controlling the gas purification apparatus according to Item 5 or 6.

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