JP2020093963A - Hydrogen production apparatus - Google Patents

Abstract

To provide a hydrogen production apparatus that supplies a stable flow rate of off gas to a reformer even when a pressure on the off gas outlet side of a hydrogen purifier is low.SOLUTION: In a hydrogen production apparatus 10, a reformed gas sent from a multi-tubular reformer 12 is separated into hydrogen and off gas containing combustible components by a hydrogen purifier 90 to purify hydrogen. The off gas sent from the hydrogen purifier 90 is stored in one of first and second off gas tanks 108, 114, and the stored off gas is supplied from the other of the first and second off gas tanks 108, 114 to a burner 26 of the multi-cylinder reformer 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hydrogen production apparatus, and more particularly to a hydrogen production apparatus that reforms a hydrocarbon raw material to produce hydrogen.

2. Description of the Related Art Conventionally, as a hydrogen production device for obtaining hydrogen, one that reforms a raw material hydrocarbon into a reformed gas by a steam reforming device and then supplies it to a PSA (Pressure Swing Adsorption) device (hydrogen purifier) is known. (See, for example, Patent Document 1). In the hydrogen production device of Patent Document 1, the off gas sent from the PSA device is returned to the steam reforming device as fuel to improve the thermal efficiency of the entire hydrogen production device.

JP, 2003-335502, A

However, the off-gas flow rate supplied from the PSA device to the steam reforming device has periodic fluctuations even in a steady state, and there is room for improvement in this respect.

Further, in order to equalize the flow rate of offgas supplied from the PSA apparatus to the steam reforming apparatus, it has been proposed to provide an offgas (buffer) tank on the offgas supply passage.

Generally, in the PSA apparatus, the higher the pressure of the compressor on the upstream side and the lower the pressure on the outlet side of the off gas, the higher the hydrogen purity of hydrogen produced. However, if the pressure on the outlet side of the offgas is too low, there is a problem that it is difficult to supply the offgas at a stable flow rate to the steam reforming apparatus even if the offgas tank is provided on the offgas supply passage.

An object of the present invention is to provide a hydrogen production device that supplies a stable flow rate of offgas to a reformer even when the pressure on the offgas outlet side of the hydrogen purifier is low.

The hydrogen producing apparatus according to claim 1, wherein a reforming unit that steam-reforms a hydrocarbon raw material to generate a reformed gas containing hydrogen as a main component, and a combustion unit that burns a combustible gas to heat the reforming unit. A reformer having a section and a reformer gas provided downstream of the reformer and separating the reformed gas delivered from the reformer into off-gas containing combustible components and hydrogen to purify hydrogen. And a off-gas supply passage for supplying the off-gas separated by the hydrogen refiner to the combustor, and the off-gas supply passage provided in parallel on the off-gas supply passage to temporarily store the off-gas and then the combustor. A plurality of off-gas tanks, first switching means for connecting or disconnecting each of the off-gas tanks and the hydrogen purifier, and second switching means for connecting or disconnecting each of the off-gas tanks and the combustion unit. And

In this hydrogen production device, the reformed gas reformed in the reforming section of the reformer is separated into off gas containing combustible components and hydrogen in the hydrogen purifier. The off gas is supplied to the combustion section of the reformer through the off gas supply passage and is used for combustion.

A plurality of offgas tanks are provided in parallel on the offgas supply passage. Further, there are provided first switching means for connecting or disconnecting each off-gas tank and the hydrogen purifier, and second switching means for connecting or disconnecting each off-gas tank and the combustion part of the reformer.

Here, some of the plurality of off-gas tanks arranged in parallel in the off-gas supply passage communicate with the hydrogen purifier by the first switching means, and shut off from the combustion section of the reformer by the second switching means. can do. Therefore, the offgas sent from the hydrogen purifier is stored in some of the plurality of offgas tanks.

Further, the other part of the plurality of off-gas tanks is cut off from the hydrogen purifier by the first switching means and communicated with the combustion part of the reformer by the second switching means. Therefore, the off-gas stored in the off-gas tank can be stably supplied to the combustion section of the reformer.

In this way, the off-gas sent from the hydrogen purifier was stored in some of the plurality of off-gas tanks, and was also stored in the combustion section of the reformer from some of the other off-gas tanks of the plurality of off-gas tanks. Off gas is supplied. Therefore, even when the pressure on the outlet side of the hydrogen purifier is low, the off gas can be stably supplied to the combustion section of the reformer.

In particular, by synchronizing the switching of the first switching means and the second switching means with the switching timing of the adsorption step/desorption step of the hydrogen purifier, the composition and volume of the offgas stored in the offgas tank become constant, and the reforming is performed. The off gas can be more stably supplied to the combustion section of the reactor.

The hydrogen production apparatus according to claim 2 is the hydrogen production apparatus according to claim 1, wherein the hydrogen production apparatus connects and disconnects the first switching means and the second switching means at predetermined time intervals, respectively. A control means for switching the gas tank is further provided, wherein the control means connects the first switching means with a part of the plurality of off-gas tanks and the hydrogen purifier, and controls another part of the plurality of parts. The off-gas tank and the hydrogen purifier are shut off, the second switching means is connected to the other off-gas tank and the combustion section, and the off-gas tank and the combustion section are shut off. Let

In this hydrogen production device, the control means controls the switching timings of the first switching means and the second switching means at predetermined time intervals, so that the off gas sent from the hydrogen purifier to some of the plurality of off gas tanks. The offgas is stored and supplied to the reformer from some of the plurality of offgas tanks.

In this way, the off-gas sent from the hydrogen purifier was stored in some of the plurality of off-gas tanks, and was also stored in the combustion section of the reformer from some of the other off-gas tanks of the plurality of off-gas tanks. Off gas is supplied. Therefore, even when the pressure on the outlet side of the hydrogen purifier is low, the off gas can be stably supplied to the combustion section of the reformer.

In particular, by synchronizing the switching timing (predetermined time) of the first switching means and the second switching means with the switching timing of the adsorption process/desorption process of the hydrogen purifier, the capacity and composition of the offgas temporarily stored in the offgas tank can be adjusted. It can be kept constant, and the composition and flow rate (pressure) of off-gas can be further leveled and then stably supplied to the combustion section of the reformer.

The hydrogen production apparatus according to claim 3 is the hydrogen production apparatus according to claim 1, wherein the hydrogen production apparatus detects pressure on the outlet side of the hydrogen purifier in the off-gas supply passage, and The control means further includes a control means for switching the off-gas tank that communicates with and cuts off the first switching means and the second switching means based on the pressure detected by the pressure detecting means, and the control means includes the first switching means. One of the plurality of off-gas tanks and the hydrogen purifier are connected to each other, and the other of the plurality of off-gas tanks and the hydrogen purifier are shut off, and the other of the off-gas tanks is turned off by the second switching means. The gas tank and the combustion unit are communicated with each other, and the part of the off-gas tank and the combustion unit are shut off.

In this hydrogen production apparatus, the control means detects the switching timing of the adsorption step/desorption step of the hydrogen purifier based on the pressure on the off-gas outlet side of the hydrogen purifier, and the first switching means is synchronized with this switching timing. The second switching means is switched.

As a result, the volume and composition of the offgas temporarily stored in the offgas tank can be made constant, and the composition and flow rate (pressure) of the offgas can be leveled and then stably supplied to the combustion section of the reformer.

Since the hydrogen production device according to the invention described in claims 1 to 3 is configured as described above, it is possible to supply a stable flow rate of offgas to the reformer even if the pressure on the offgas outlet side of the hydrogen purifier is low.

It is a schematic block diagram which showed the hydrogen production apparatus which concerns on 1st Embodiment of this invention. It is a sectional view showing a multi-cylinder type reformer of a hydrogen production device concerning a 1st embodiment of the present invention. It is the block diagram which showed the control part of the hydrogen production apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the off gas flow state in the hydrogen production apparatus which concerns on 1st Embodiment of this invention, (A) a 1st off gas tank is a storage state, a 2nd off gas tank is a supply state, (B) is a 2nd The off-gas tank is in the storage state and the first off-gas tank is in the supply state. It is a schematic block diagram which showed the hydrogen production apparatus which concerns on 2nd Embodiment of this invention. It is the block diagram which showed the control part of the hydrogen production apparatus which concerns on 2nd Embodiment of this invention.

[First Embodiment]
An example of the hydrogen production device according to the first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the hydrogen production apparatus 10 according to the present embodiment is a multi-cylinder reformer (hereinafter, referred to as a “reformer”) that produces a reformed gas obtained by steam reforming a hydrocarbon (city gas). 12), a compressor 80 for compressing the reformed gas, and a hydrogen purifier 90 for purifying hydrogen gas by removing impurities from the compressed reformed gas. Further, the hydrogen production apparatus 10 includes a pre-pressurization water separation unit 50 and a post-pressurization water separation unit 60 that separate and remove water from the reformed gas on the upstream side and the downstream side of the compressor 80, respectively, and the reforming The reactor 12 is provided with a combustion exhaust gas water separation unit 70 for separating and removing water from combustion exhaust gas described later.

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

(Multiple cylinder reformer)
As shown in FIG. 2, the multi-tubular reformer 12 has a plurality of tubular walls 21, 22, 23, 24 (hereinafter, may be referred to as “cylindrical walls 21-24”) arranged in multiple layers. Have The plurality of cylindrical walls 21 to 24 are formed in, for example, a cylindrical shape or an elliptic cylindrical shape. A combustion chamber 25 is formed inside the first cylindrical wall 21 from the inner side among the plurality of cylindrical walls 21 to 24, and a burner 26 is arranged downward on the combustion chamber 25. There is. The off gas of the hydrogen purifier 90 can be supplied as fuel from the combustible gas supply pipe 38 to the burner 26. The multi-tubular reformer 12 is an example of a reformer. Further, an air supply pipe 40 for supplying combustion air from the outside is connected to the upper end of the combustion chamber 25. The burner 26 is further connected to a raw material branch pipe 33A obtained by branching city gas from the raw material supply pipe 33. An air branch pipe 40A branched from the air supply pipe 40 is connected to the raw material branch pipe 33A. A gas in which city gas is mixed with air is supplied to the burner 26 separately from the off gas. Either one or both of the off gas for combustion and the city gas can be supplied as needed. The burner 26 corresponds to the combustion section.

A combustion exhaust gas passage 27 is formed between the first tubular wall 21 and the second tubular wall 22. A lower end portion of the combustion exhaust gas passage 27 communicates with the combustion chamber 25, and a gas exhaust pipe 28 for exhausting gas is connected to an upper end portion of the combustion exhaust gas passage 27. The combustion exhaust gas discharged from the combustion chamber 25 flows from the lower side to the upper side in the combustion exhaust gas flow path 27 and is sent to the combustion exhaust gas water separation unit 70 through the gas discharge pipe 28.

A first flow path 31 is formed between the second tubular wall 22 and the third tubular wall 23. An upper portion of the first flow passage 31 is formed as a preheating flow passage 32, and a raw material supply pipe 33 for supplying city gas and reforming water are supplied to an upper end portion of the preheating flow passage 32. Is connected to the reforming water supply pipe 34. Further, a spiral member 35 is provided between the second cylindrical wall 22 and the third cylindrical wall 23, and the preheating flow passage 32 is formed in a spiral shape by the spiral member 35. There is. The raw material supply pipe 33 is an example of a flow passage pipe.

City gas can be supplied to the preheating channel 32 from the raw material supply pipe 33, and further reforming water can be supplied from the reforming water supply pipe 34. The city gas and the reforming water flow from the upper side to the lower side in the preheating channel 32, and are heat-exchanged with the combustion exhaust gas through the second cylindrical wall 22 to vaporize the water. In the preheating channel 32, the mixed gas is generated by mixing the city gas and the vapor-phase reforming water (steam).

A reforming catalyst layer 36 is provided below the preheating channel 32 in the first channel 31, and the mixed gas generated in the preheating channel 32 is supplied to the reforming catalyst layer 36. It is a configuration. The reforming catalyst layer 36 receives heat from the combustion exhaust gas flowing through the combustion exhaust gas passage 27 and undergoes a steam reforming reaction of the mixed gas to generate a reformed gas containing hydrogen as a main component.

Further, a second flow path 42 is formed between the third tubular wall 23 and the fourth tubular wall 24. The lower end of the second flow path 42 communicates with the lower end of the first flow path 31. A lower portion of the second flow passage 42 is formed as a reformed gas flow passage 43, and a reformed gas discharge pipe 44 is connected to an upper end portion of the second flow passage 42.

Further, a CO shift conversion catalyst layer 45 is provided above the reformed gas passage 43 in the second passage 42, and the reformed gas generated in the reformed catalyst layer 36 is the reformed gas flow. After passing through the passage 43, it is supplied to the CO shift catalyst layer 45. In the CO conversion catalyst layer 45, carbon monoxide contained in the reformed gas reacts with water vapor to be converted into hydrogen and carbon dioxide, and carbon monoxide can be reduced.

Further, an oxidant gas supply pipe 46 is connected to the upper side of the CO shift catalyst layer 45, and a CO selective oxidation catalyst layer 47 is provided above the CO shift catalyst layer 45 in the second flow path 42. ing. The oxidizing gas introduced through the oxidizing gas supply pipe 46 and the reformed gas that has passed through the CO shift catalyst layer 45 are supplied to the CO selective oxidation catalyst layer 47. In the CO selective oxidation catalyst layer 47, carbon monoxide reacts with oxygen and is converted into carbon dioxide on a noble metal catalyst such as platinum or ruthenium, and carbon monoxide can be removed. The reformed gas G1 in which carbon monoxide is reduced in the CO shift catalyst layer 45 and the CO selective oxidation catalyst layer 47 is discharged through the reformed gas discharge pipe 44. The CO selective oxidation catalyst layer 47 is not essential, and may be omitted.

As shown in FIG. 1, the reformed gas generated in the multi-tubular reformer 12 passes through the pre-pressurization water separation unit 50, the compressor 80, the post-pressurization water separation unit 60, and the hydrogen purifier 90 in this order. Flowing. That is, in the gas flow direction, from the upstream side to the downstream side, the multi-tubular reformer 12, the pre-pressurization water separation unit 50, the compressor 80, the post-pressurization water separation unit 60, and the hydrogen purifier 90 are arranged in this order. It is arranged.

(Pre-pressurization water separator)
The downstream end of a reformed gas discharge pipe 44, into which the reformed gas G1 flows from the multi-cylinder reformer 12, is connected to the pre-pressurization water separation unit 50. A water recovery pipe 59 is connected to the bottom of the pre-pressurization water separation unit 50, and a communication channel pipe 56 is connected to the top of the pre-pressurization water separation unit 50. The reformed gas G1 is condensed and separated in the heat exchanger HE1 arranged in the reformed gas discharge pipe 44 upstream of the pre-pressurization water separation unit 50 by cooling by heat exchange with cooling water, and before the pressurization. Water (liquid phase) can be stored under the water separation unit 50. The water (liquid phase) is sent to the water recovery pipe 59. The reformed gas G2 after the water is condensed is sent to the communication flow path pipe 56.

(Compressor)
In the compressor 80, there are a communication flow passage pipe 56 through which the reformed gas G2 from the pre-pressurization water separation unit 50 flows, and a communication flow passage pipe 66 through which the reformed gas G2 supplied to the post-pressurization water separation unit 60 flows. It is connected. The compressor 80 is capable of compressing the reformed gas supplied from the pre-pressurization water separation unit 50 and supplying it to the post-pressurization water separation unit 60.

(Water separation unit after pressurization)
To the post-pressurization water separation unit 60, a downstream end of a communication flow pipe 66 that allows the reformed gas G2 to flow from the compressor 80 is connected. A water recovery pipe 69 is connected to the bottom of the post-pressurization water separation unit 60, and a communication channel pipe 68 is connected to the top of the post-pressurization water separation unit 60. The reformed gas G2 is condensed and separated by cooling by heat exchange with cooling water in the heat exchanger HE2 arranged in the communication flow path pipe 66 upstream of the post-pressurization water separation section 60, and the post-pressurization water is separated. Water (liquid phase) can be stored under the separation unit 60. The water (liquid phase) is sent to the water recovery pipe 69. The reformed gas G3 after the water is condensed is sent to the communication flow path pipe 68.

(Hydrogen refiner)
In the hydrogen purifier 90, the downstream end of the communication flow pipe 68 through which the reformed gas G3 from the post-pressurization water separation unit 60 flows and the off-gas of the hydrogen purifier 90 supplied to the multi-tube reformer 12 flow. The upstream end of the combustible gas supply pipe 38 is connected.

As the hydrogen purifier 90, a PSA device is used as an example. The hydrogen purifier 90 includes a pair of adsorption tanks, one adsorption tank performs an adsorption step of adsorbing impurities on the adsorbent, and the other adsorption tank performs a desorption step of desorbing the impurities adsorbed on the adsorbent, Next, the desorption process is performed on one adsorption layer and the adsorption process is performed on the other adsorption layer. By repeating this periodically, the reformed gas G3 is continuously separated into impurities containing a combustible gas and hydrogen, and hydrogen is purified. The purified hydrogen is delivered to the hydrogen supply pipe 92, can be stored in a tank (not shown), or can be delivered to the hydrogen supply line.

The off gas of the hydrogen purifier 90 can be supplied from the combustible gas supply pipe 38 to the burner 26 (see FIG. 2) of the multi-cylinder reformer 12 as fuel.

(Combustion exhaust gas water separation unit)
The downstream end of a gas exhaust pipe 28 that guides the combustion exhaust gas from the combustion exhaust gas flow path 27 is connected to the combustion exhaust gas water separation unit 70. A water recovery pipe 78 is connected to the bottom of the combustion exhaust gas water separation unit 70, and a gas discharge pipe 76 is connected to the upper portion of the combustion exhaust gas water separation unit 70. The combustion exhaust gas discharged from the combustion chamber 25 is separated and condensed in the heat exchanger HE3 arranged in the gas discharge pipe 28 upstream of the combustion exhaust gas water separation unit 70 by cooling by heat exchange with cooling water. Water (liquid phase) can be stored under the combustion exhaust gas water separation unit 70. The water (liquid phase) is sent to the water recovery pipe 78. The combustion exhaust gas after the water is condensed is discharged from the gas discharge pipe 76 to the outside.

The downstream ends of the water recovery pipe 59, the water recovery pipe 69, and the water recovery pipe 78 are connected to the reforming water supply pipe 34. The reforming water supply pipe 34 is provided with a water treatment device (ion exchange resin) 34A for removing dissolved ionic components. The external water supply unit 17 is connected to the reforming water supply pipe 34. Pure water or city water, for example, is supplied from the external water supply unit 17.

Further, the reforming water supply pipe 34 is provided with a pump P1. The water separated by the pre-pressurization water separation unit 50, the post-pressurization water separation unit 60, the combustion exhaust gas water separation unit 70, or the water supplied from the external water supply unit 17 is sent to the multi-tubular reformer 12 by the pump P1. It is a configuration to be supplied.

(Off gas tank)
As shown in FIG. 1, the combustible gas supply pipe 38 is branched into a first combustible gas supply pipe 100 and a second combustible gas supply pipe 102 on the way. The first combustible gas supply pipe 100 and the second combustible gas supply pipe 102 join again on the downstream side. Further, in the combustible gas supply pipe 38, the upstream side of the first combustible gas supply pipe 100 and the second combustible gas supply pipe 102 is an upstream combustible gas supply pipe 104, and the downstream side is a downstream combustible gas supply pipe 106. .. The combustible gas supply pipe 38 corresponds to the “off gas supply passage”.

A first off-gas tank 108 is arranged in the first combustible gas supply pipe 100, and a first on-off valve 110 and a second on-off valve 112 are provided on the upstream side and the downstream side of the first off-gas tank 108, respectively. It is provided. That is, by opening and closing the first on-off valve 110 and the second on-off valve 112, the off gas is supplied from the hydrogen purifier 90 to the first off-gas tank 108, and the burner 26 of the reformer 12 is supplied from the first off-gas tank 108. It is configured to be able to supply off-gas.

Similarly, the second combustible gas supply pipe 102 is also provided with a second off-gas tank 114, and a third on-off valve 116 and a fourth on-off valve 118 are provided on the upstream side and the downstream side of the first off-gas tank 114, respectively. Is provided. That is, by opening and closing the third on-off valve 116 and the fourth on-off valve 118, the off gas is supplied from the hydrogen purifier 90 to the second off-gas tank 114, or from the second off-gas tank 114 to the burner 26 of the reformer 12. It is configured to be able to supply off-gas.

The first opening/closing valve 110, the second opening/closing valve 112, the third opening/closing valve 116, and the fourth opening/closing valve 118 (hereinafter, sometimes referred to as “first to fourth opening/closing valves 110 to 118”) are controlled. The configuration is controlled by the unit 120 (see FIG. 3).

Further, the capacities of the first off-gas tank 108 and the second off-gas tank 114 (hereinafter sometimes referred to as “first and second off-gas tanks 108 and 114”) are the amount of off-gas sent from the hydrogen purifier 90 and the burner 26. It is set in consideration of the balance of the amount of off gas to be supplied to, the pressure of the first and second off gas tanks 108 and 114, and the like.

The first and second offgas tanks 108 and 114 correspond to “offgas tanks”. Further, the first opening/closing valve 110 and the third opening/closing valve 116 correspond to “first switching means”. Further, the second opening/closing valve 112 and the fourth opening/closing valve 118 correspond to "second switching means". Further, the control unit 120 corresponds to “control means”.

(Action)
Next, the operation of the hydrogen production device 10 will be described.

City gas is supplied from the raw material supply pipe 33 to the multi-cylinder reformer 12. As shown in FIG. 2, the city gas supplied to the multi-cylinder reformer 12 is heated while being mixed with the reforming water in the preheating channel 32 of the multi-cylinder reformer 12, and the reforming catalyst It is supplied to the layer 36. The reforming catalyst layer 36 receives heat from the combustion exhaust gas flowing through the combustion exhaust gas passage 27, and a reforming gas containing hydrogen as a main component is generated from the mixed gas by the steam reforming reaction.

The reformed gas is supplied to the CO shift catalyst layer 45 through the reformed gas passage 43. In the CO conversion catalyst layer 45, carbon monoxide contained in the reformed gas reacts with steam to be converted into hydrogen and carbon dioxide, and carbon monoxide is reduced.

Further, the reformed gas that has passed through the CO conversion catalyst layer 45 is supplied to the CO selective oxidation catalyst layer 47 together with the oxidizing gas (air) supplied from the oxidizing gas supply pipe 46, and carbon monoxide is converted into oxygen on the precious metal catalyst. Reacts with and is converted to carbon dioxide, and carbon monoxide is removed. The reformed gas G1 in which carbon monoxide is reduced in the CO selective oxidation catalyst layer 47 is sent to the reformed gas discharge pipe 44.

As shown in FIG. 1, the reformed gas G1 is supplied to the pre-pressurization water separation unit 50 via the reformed gas discharge pipe 44. In the pre-pressurization 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 59. The reformed gas G2 from which the water has been separated is supplied to the compressor 80 from the communication flow path pipe 56 and is compressed by the compressor 80.

The compressed reformed gas G2 is supplied from the communication flow path pipe 66 to the water separation unit 60 after pressurization. In the post-pressurization water separation unit 60, water condensed by cooling by heat exchange in the heat exchanger HE2 is stored and sent to the water recovery pipe 69. The reformed gas G3 from which water has been separated is supplied to the hydrogen purifier 90 from the communication flow path pipe 68.

In the hydrogen purifier 90, the reformed gas G3 is separated into hydrogen and off gas that is an impurity, and the hydrogen is sent to the hydrogen supply pipe 92. The delivered hydrogen is stored in a tank (not shown) or sent to a hydrogen supply line.

The hydrogen purifier 90 employs a pressure swing method, in which one of the pair of adsorption tanks performs an adsorption step in which impurities other than hydrogen are adsorbed by the adsorbent, and the other adsorption tank uses the adsorbent. A desorption process is performed in which the adsorbed impurities are desorbed. Subsequently, the desorption process is performed on one adsorption layer, and the adsorption process is performed on the other adsorption layer. By repeating this adsorption step and desorption step in each adsorption tank in a constant cycle, hydrogen is continuously purified in the hydrogen purifier 90, while periodically changing composition and flow rate (pressure). Off gas is being delivered.

The control unit 120 switches opening/closing of the first to fourth on-off valves 110 to 118 in synchronization with the switching cycle of the adsorption process and desorption process of the hydrogen purifier 90, that is, at a constant cycle.

Specifically, as shown in FIG. 4(A), at the timing when the adsorption process is started in one adsorption tank of the hydrogen purifier 90 and the desorption process is started in the other adsorption tank, the control unit 120 The first opening/closing valve 110 and the fourth opening/closing valve 118 are opened, and the second opening/closing valve 112 and the third opening/closing valve 116 are closed.

As a result, the off gas is supplied from the hydrogen purifier 90 to the first off gas tank 108 via the upstream combustible gas supply pipe 104 and the first combustible gas supply pipe 100, and is stored therein.

Further, the off gas stored in the burner 26 of the reformer 12 is supplied as fuel from the second off gas tank 114 through the second combustible gas supply pipe 102 and the downstream combustible gas supply pipe 106.

On the other hand, as shown in FIG. 4B, in the hydrogen purifier 90, the desorption process is started in one adsorption tank and the adsorption process is started in the other adsorption tank, and the control unit 120 causes the second opening/closing valve to start. 112 and the third opening/closing valve 116 are opened, and the first opening/closing valve 110 and the fourth opening/closing valve 118 are closed.

As a result, the off gas is supplied from the hydrogen purifier 90 to the second off gas tank 114 via the upstream combustible gas supply pipe 104 and the second combustible gas supply pipe 102, and is stored therein.

Further, the off gas stored in the burner 26 of the reformer 12 is supplied as fuel from the first off gas tank 108 via the first combustible gas supply pipe 100 and the downstream combustible gas supply pipe 106.

In this way, the opening/closing control of the first to fourth opening/closing valves 110 to 118 is performed by the control unit 120, so that the off gas sent from the hydrogen purifier 90 is supplied to one of the first and second off gas tanks 108 and 114. Once stored, the off gas stored in the burner 26 of the reformer 12 is supplied from the other of the first and second off gas tanks 108 and 114.

Therefore, regardless of the composition/flow rate (pressure) variation of the offgas at the outlet side of the hydrogen purifier 90 due to the switching of the adsorption step and the desorption step of the hydrogen purifier 90, the offgas of the equalized flow rate (pressure) is used as the reformer. It is supplied to 12 burners 26.

In the combustion chamber 25 of the multi-cylinder reformer 12, the burner 26 combusts the off gas supplied from the first and second off gas tanks 108 and 114. The combustion exhaust gas is supplied from the combustion chamber 25 to the combustion exhaust gas water separation unit 70 via the gas exhaust pipe 28. 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 78. The combustion exhaust gas from which the water has been separated is discharged from the gas discharge pipe 76 to the outside.

The reforming water is supplied from the reforming water supply pipe 34 to the multi-cylinder reformer 12 by driving the pump P1.

In the hydrogen production device 10 of the present embodiment, the first and second off gas tanks 108 and 114 are arranged in parallel on the combustible gas supply pipe 38, and the first to fourth opening/closing valves 110 to 110 are provided on the upstream side and the downstream side thereof. 118 is provided. Therefore, the control unit 120 controls the opening and closing of the first to fourth on-off valves 110 to 118 to supply the off gas from the hydrogen purifier 90 to one of the first and second off gas tanks 108 and 114 and store the off gas. The off gas stored in the burner 26 of the reformer 12 can be supplied from the other of the first and second off gas tanks 108 and 114.

That is, regardless of pressure fluctuation due to adsorption/desorption of the hydrogen purifier 90, the off gas whose composition and flow rate (pressure) are leveled is supplied from the first and second off gas tanks 108 and 114 to the burner 26 of the reformer 12. can do.

In particular, since the first to fourth on-off valves 110 to 118 are switched in synchronization with the switching timing of the adsorption process and the desorption process in the hydrogen purifier 90, the off gas stored in the first and second off gas tanks 108 and 114 is stored. The composition and volume of are constant, and the composition and flow rate (pressure) of the off gas supplied from the first and second off gas tanks 108 and 114 to the burner 26 of the reformer 12 are further equalized.

Therefore, the degree of compression of the reformed gas G2 by the compressor 80 (the pressure of the reformed gas G3 on the upstream side of the hydrogen purifier 90) is increased, and the pressure on the off-gas outlet side of the hydrogen purifier 90 is lowered to reduce the pressure. Even if the difference is increased, the leveling of the composition and flow rate (pressure) of the off gas supplied to the reformer 12 is maintained.

That is, it is possible to improve the hydrogen purity of the product hydrogen by increasing the pressure difference between the upstream side of the hydrogen purifier 90 and the off-gas outlet side of the hydrogen purifier 90, and to stably supply the off gas to the burner 26. be able to.

[Second Embodiment]
Next, a hydrogen production device according to the second embodiment of the present invention will be described. In this embodiment, the same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, the hydrogen production apparatus 200 according to the second embodiment differs from the hydrogen production apparatus 10 of the first embodiment only in that a pressure gauge 202 is arranged on the upstream combustible gas supply pipe 104. Further, only the operation relating to this different point will be described, and the detailed description of the same operation and effect as the first embodiment will be omitted.

As shown in FIG. 5, the pressure gauge 202 detects the pressure on the off gas outlet side of the hydrogen purifier 90 in the upstream combustible gas supply pipe 104 and outputs it to the control unit 120 (see FIG. 6). The pressure gauge 202 corresponds to "pressure detecting means".

The operation of the hydrogen production device 200 configured as above will be described.
The control unit 120 of the hydrogen production apparatus 200 detects the switching timing between the adsorption process and the desorption process in the hydrogen purifier 90 based on the output of the pressure gauge 202, and switches the opening and closing of the first to fourth on-off valves 110 to 118. ..

That is, when the first opening/closing valve 110 and the fourth opening/closing valve 118 are opened and the second opening/closing valve 112 and the third opening/closing valve 116 are closed (see FIG. 4(A)), the second opening/closing valve 112, The opening and closing of the third opening/closing valve 116 and the closing of the first opening/closing valve 110 and the fourth opening/closing valve 118 (see FIG. 4B) are switched.

As described above, in the hydrogen production apparatus 200, the pressure of the upstream combustible gas supply pipe 104 on the downstream side of the hydrogen purifier 90 is detected by the pressure gauge 202, and the adsorption process of the hydrogen purifier 90 is performed based on the pressure fluctuation. Since the timing of switching to the desorption process is detected, the first to fourth on-off valves 110 to 118 can be switched more accurately. As a result, the composition of the burner 26 of the reformer 12 from the first and second off-gas tanks 108 and 114 is maintained regardless of the pressure fluctuation on the outlet side of the hydrogen purifier 90 due to the switching between the adsorption process and the desorption process of the hydrogen purifier 90. The off gas whose flow rate (pressure) is leveled is supplied to ensure stable combustion of the burner 26.

In particular, even when there is a change in the time required for the adsorption process/desorption process, the switching timing of opening/closing the first to fourth opening/closing valves 110 to 118 can be made to correspond to this. Therefore, the composition and capacity of the off gas stored in the first and second off gas tanks 108 and 114 can be kept constant, and the composition and volume of the burner 26 of the reformer 12 from the first and second off gas tanks 108 and 114 can be maintained. The off gas having a more uniform flow rate (pressure) is supplied. That is, more stable combustion of the burner 26 is ensured.

(Other)
The hydrogen production apparatuses 10 and 200 according to the first and second embodiments have the first offgas tank 108 and the second offgas tank 114 arranged in parallel, but the invention is not limited to this. That is, by providing three or more off-gas tanks in parallel and switching them, the leveled off-gas is supplied to the burner 26 of the reformer 12 even if the pressure of the off-gas on the outlet side of the hydrogen purifier 90 is low. Anything that can be done will do.

Further, when three or more off-gas tanks are provided in the hydrogen production apparatus, for example, when three off-gas tanks are provided, the off-gas is supplied from the hydrogen purifier 90 to one off-gas tank and stored. The offgas stored in the reformer 12 may be supplied from the individual offgas tanks, and one offgas tank may be controlled to maintain the stored state. The three states may be controlled to be switched in order, or the gas tank in the storage state is not controlled to be switched, and the offgas is supplied to the reformer 12 only when the supply of the offgas to the reformer is insufficient. May be.

That is, when three or more offgas tanks are arranged in parallel, a predetermined action can be achieved if at least two offgas tanks are switched as described above.

Further, the switching control for selectively communicating the off-gas tank with the hydrogen purifier 90 or (the burner 26 of) the reformer 12 is automatically performed based on a predetermined time interval or the outlet side pressure fluctuation of the hydrogen purifier 90. However, the switching control may be automatically performed by other means, or the operator may manually perform the switching control.

Further, in the hydrogen producing apparatuses 10 and 200 according to the first and second embodiments, the case where the hydrogen purifier 90 is the PSA apparatus has been described, but the hydrogen purifier that causes the flow rate (pressure) variation and the composition variation of the offgas. If so, it is not limited to this.

In the hydrogen production device 10 according to the first embodiment, the first to fourth on-off valves 110 to 118 are switched in synchronization with the switching cycle of the adsorption process and the desorption process of the hydrogen purifier 90, and the hydrogen production of the second embodiment is performed. In the device 200, the first to fourth on-off valves 110 to 118 are switched based on the pressure fluctuation on the off-gas outlet side of the hydrogen purifier 90, but the invention is not limited to this. A plurality of off-gas tanks are provided in parallel on the off-gas outlet side of the hydrogen purifier 90, and off-gas is supplied to and stored from a part of the hydrogen purifier 90 in the burner 26 of the reformer 12. It suffices that the off gas whose flow rate and composition are leveled is supplied to the burner 26 by repeatedly switching the supply of.

In the hydrogen production device 10 according to the first embodiment, the first to fourth on-off valves 110 to 118 are switched in synchronization with the switching cycle of the hydrogen purifier 90 between the adsorption process and the desorption process. The first to fourth on-off valves 110 to 118 may be switched in synchronization with a cycle that is an integral multiple of the process switching cycle.

In addition, in the hydrogen production devices 10 and 200 of the embodiment according to the series, in order to selectively communicate the first and second offgas tanks 108 and 114 with the hydrogen purifier 90 and the reformer 12, the first to the first. Although the four on-off valves 110 to 118 are provided, the invention is not limited to this. For example, a three-way valve may be provided at the branch position of the upstream combustible gas supply pipe 104 and the downstream combustible gas supply pipe 106.

10, 200, Hydrogen production device 12 Multiple cylinder reformer (reformer)
26 burners (burning section)
36 Reforming catalyst layer (reforming section)
38 Combustible gas supply pipe (off gas supply flow path)
90 Hydrogen Purifier 108 First Off Gas Tank (Off Gas Tank)
110 First on-off valve (first switching means)
112 Second on-off valve (second switching means)
114 Second Off Gas Tank (Off Gas Tank)
116 Third on-off valve (first switching means)
118 4th on-off valve (2nd switching means)
120 control unit (control means)

Claims (3)

A reformer having a reforming unit that steam-reforms a hydrocarbon raw material to generate a reformed gas containing hydrogen as a main component, and a combustion unit that burns a combustible gas to heat the reforming unit,
A hydrogen purifier that is provided on the downstream side of the reformer and separates the reformed gas sent from the reformer into hydrogen and an off gas containing a combustible component to purify hydrogen.
An off-gas supply flow path for supplying the off-gas separated by the hydrogen purifier to the combustion unit,
A plurality of off-gas tanks that are provided in parallel on the off-gas supply flow path, temporarily store the off-gas, and then supply the off-gas to the combustion unit,
First switching means for connecting or disconnecting each of the off-gas tanks and the hydrogen purifier;
Second switching means for connecting or disconnecting each of the off-gas tanks and the combustion section;
Hydrogen production device equipped with. The hydrogen production apparatus further includes control means for switching the off-gas tank, which communicates with and cuts off the first switching means and the second switching means at predetermined time intervals,
The control means connects the first switching means to a part of the plurality of off-gas tanks and the hydrogen purifier, and connects the other part of the plurality of off-gas tanks and the hydrogen purifier. The hydrogen production apparatus according to claim 1, wherein the hydrogen is produced by shutting off the second switching means and communicating the other part of the off-gas tank with the combustion part to shut off the part of the off-gas tank and the combustion part. .. The hydrogen production apparatus, pressure detection means for detecting the pressure of the outlet side of the hydrogen purifier in the off-gas supply flow path,
Control means for switching the off-gas tank that communicates with and blocks the first switching means and the second switching means based on the pressure detected by the pressure detecting means,
Further equipped with,
The control means connects the first switching means to a part of the plurality of off-gas tanks and the hydrogen purifier, and connects the other part of the plurality of off-gas tanks and the hydrogen purifier. The hydrogen production apparatus according to claim 1, wherein the hydrogen is produced by shutting off the second switching means and communicating the other part of the off-gas tank with the combustion part to shut off the part of the off-gas tank and the combustion part. ..