JP2020100534A - Hydrogen production equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen production apparatus having a simple configuration, reducing the concentration of carbon monoxide in off-gas and discharging it into the outside air. A hydrogen production apparatus 10 separates an off-gas OG, which is an impurity, from a reformed gas G3 by a hydrogen purifier 90, and supplies the off-gas OG to a flare stack 100 via an off-gas supply pipe 102. As a result, carbon monoxide contained in the off-gas is converted into carbon dioxide by combustion (oxidation reaction) in the flare stack 100. In this way, carbon monoxide in the off-gas OG is converted to carbon dioxide (the concentration of monoxide is reduced) and discharged into the outside air as combustion exhaust gas. [Selection diagram] Fig. 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 producing 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. (For example, see Patent Document 1). In the hydrogen production apparatus of Patent Document 1, the off gas sent from the PSA apparatus is returned to the steam reforming apparatus as fuel, thereby improving the thermal efficiency of the entire hydrogen production apparatus.

JP, 2003-335502, A

However, since the off-gas flow rate supplied from the PSA apparatus to the steam reforming apparatus has a periodic fluctuation even in a steady state, the flow rate control becomes complicated, and there is room for improvement in terms of simplification of the apparatus.

On the other hand, from the viewpoint of simplification of the hydrogen production device, it may be considered to discharge the off gas from the hydrogen purifier into the outside air. In this case, the carbon monoxide (concentration) contained in the offgas becomes a problem.

An object of the present invention is to provide a hydrogen production device having a simple configuration, which reduces the concentration of carbon monoxide in off gas and discharges it into the outside air.

The hydrogen producing apparatus according to claim 1, wherein a hydrocarbon is supplied as a raw material, and a reformer that reforms the hydrocarbon to generate a reformed gas containing hydrogen as a main component and containing carbon monoxide, A hydrogen purifier that is connected to the reformer and that purifies the product hydrogen by separating the reformed gas into product hydrogen and off gas that is an impurity; and communicating the hydrogen purifier with the outside air, An off-gas flow path through which the off-gas discharged from the device flows, and a flare stack provided on the off-gas flow path or a carbon monoxide selective oxidation section for selectively oxidizing carbon monoxide.

In this hydrogen production device, the reformed gas generated in the reformer is supplied to the hydrogen purifier, whereby the reformed gas is separated into product hydrogen and off-gas which is an impurity.

The off gas separated by the hydrogen purifier flows on the off gas passage and is supplied to the flare stack or the carbon monoxide selective oxidation section provided on the off gas passage. When the off gas is supplied to the flare stack, the carbon monoxide contained in the off gas is converted into carbon dioxide by the combustion in the flare stack. When the off gas is supplied to the carbon monoxide selective oxidation unit, the carbon monoxide contained in the off gas is selectively oxidized and converted into carbon dioxide.

Thus, the carbon monoxide contained in the off-gas separated by the hydrogen purifier is converted into carbon dioxide in the flare stack or the carbon monoxide/other-carbon selective oxidation unit, so that the carbon monoxide in the off-gas is removed or After being reduced, the off gas is discharged into the outside air as exhaust gas.

Therefore, in this hydrogen production device, by supplying the off gas to the flare stack or the carbon monoxide selective oxidation section provided on the off gas flow path, the carbon monoxide in the off gas is removed or reduced to the outside air as exhaust gas. Can be discharged. That is, the off-gas can be treated with a simple configuration of the entire hydrogen production apparatus.

The hydrogen production apparatus according to claim 2 is the hydrogen production apparatus according to claim 1, wherein a water supply pipe for supplying water as a raw material to the reformer and a water supply pipe provided on the water supply pipe are provided. And a heat recovery unit in which the water recovers combustion heat or heat of oxidation reaction of the carbon monoxide selective oxidation unit.

In this hydrogen production device, a heat recovery unit for recovering the combustion heat of the flare stack or the heat of oxidation reaction of the carbon monoxide selective oxidation unit is provided on the water supply pipe for supplying water as a raw material to the reformer. ing.

Therefore, the off gas generated in the hydrogen purifier is supplied to the flare stack or the carbon monoxide selective oxidation section, whereby the contained carbon monoxide is oxidized (converted into carbon dioxide). At this time, the heat of combustion of the off gas in the flare stack or the reaction heat of the oxidation reaction (exothermic reaction) of carbon monoxide in the off gas in the carbon monoxide selective oxidation unit is recovered in the heat recovery unit, and the water flowing through the water supply pipe is Be heated.

Therefore, water that is supplied to the reformer as a raw material and is heated (preheated) in the reformer to be mixed gas is preheated in the heat recovery unit. As a result, the amount of heat required to heat the water in the reformer can be reduced. That is, the thermal efficiency of the hydrogen production device is improved.

The hydrogen producing apparatus according to claim 3 is the hydrogen producing apparatus according to claim 1 or 2, wherein the reformer reforms the hydrocarbon to generate a primary reformed gas containing hydrogen as a main component. And a carbon monoxide removing unit for producing a reformed gas in which carbon monoxide is reduced from the primary reformed gas only by an aqueous shift reaction and sending the reformed gas to the hydrogen purifier.

In the reformer of this hydrogen production device, the reforming section produces the primary reformed gas, and the carbon monoxide removing section produces the reformed gas in which carbon monoxide is reduced (removed) from the primary reformed gas, Supplying to hydrogen purifier. Therefore, the concentration of carbon monoxide in the off gas delivered from the hydrogen purifier is reduced.

By converting this carbon monoxide in the offgas into carbon dioxide by burning it in a flare stack or by passing it through a carbon monoxide selective oxidation part, it is discharged into the outside air. The concentration is further reduced and the exhaust gas is discharged into the outside air.

On the other hand, in the carbon monoxide removing section of the reformer, carbon monoxide is reduced from the primary reformed gas only by the water shift reaction. That is, since the method of introducing air to oxidize carbon monoxide is not used to reduce carbon monoxide from the primary reformed gas, the reformed gas supplied from the reformer to the hydrogen purifier contains air. The mixed argon is prevented. Therefore, since argon, which has a high load to be removed by the hydrogen purifier, is not mixed in the reformed gas, the purity of the product hydrogen can be improved or the load on the hydrogen purifier can be reduced.

Since the hydrogen production device according to the invention of claims 1 to 3 has the above-mentioned configuration, it is possible to reduce the carbon monoxide concentration in the offgas and discharge it to the outside air with a simple configuration.

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 concerning a 1st embodiment of the present invention. It is a schematic block diagram which showed the hydrogen production apparatus which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which showed the hydrogen production apparatus which concerns on 3rd Embodiment of this invention. It is the schematic block diagram which showed the hydrogen production apparatus which concerns on the other example of 3rd Embodiment of this invention. It is sectional drawing which showed the multiple cylinder reformer which concerns on 4th Embodiment of this invention. It is sectional drawing which showed the multiple cylinder reformer which concerns on the other example of 4th 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. 1 and 2.

<Hydrogen production equipment>
As shown in FIG. 1, the hydrogen production apparatus 10 includes a multi-cylinder reformer (hereinafter, may be referred to as a “reformer”) 12 that produces a reformed gas obtained by steam reforming hydrocarbons (city gas). 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. The hydrogen production device 10 includes a pre-pressurization water separation unit 50, a post-pressurization water separation unit 60, which separates and removes water from the reformed gas on the upstream side and the downstream side of the compressor 80, respectively, and a reformer 12 to be described later. And a combustion exhaust gas water separation unit 70 for separating and removing water from the combustion exhaust gas.

The hydrogen production device 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 includes 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 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. A raw material branch pipe 33A branched from a raw material supply pipe 33 for supplying city gas is further connected to the burner 26. An air branch pipe 40A branched from the air supply pipe 40 is connected to the raw material branch pipe 33A. Therefore, the burner 26 is configured to be supplied with gas in which city gas is mixed with air.

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.

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 reforming water (steam) in the vapor phase.

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. The reforming catalyst layer 36 corresponds to the “reforming section”.

Further, a second flow path 42 is formed between the third cylindrical wall 23 and the fourth cylindrical 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. The second flow path 42 corresponds to the “carbon monoxide selective oxidation part”.

Further, a CO shift 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 conversion catalyst layer 45. In the CO shift catalyst layer 45, carbon monoxide contained in the reformed gas reacts with steam to be converted into hydrogen and carbon dioxide (aqueous shift reaction), and carbon monoxide in the reformed gas 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 oxidant gas (for example, air) introduced through the oxidant 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, for example, only carbon monoxide in the reformed gas is selectively reacted with oxygen on a noble metal catalyst such as platinum or ruthenium to be converted into carbon dioxide, and the carbon monoxide is removed from the reformed gas. It is supposed to be removable. 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.

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.

(Water separator before pressurization)
The downstream end of the 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 by cooling by heat exchange with cooling water in the heat exchanger HE1 arranged in the reformed gas discharge pipe 44 upstream of the pre-pressurization water separation unit 50, 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 provided 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 G2 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 in the heat exchanger HE2 arranged in the communication flow path pipe 66 upstream of the post-pressurization water separation unit 60 by cooling by heat exchange with cooling water, and the post-pressurization water 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, the upstream end of the hydrogen supply pipe 92 to which purified hydrogen is delivered, and the hydrogen purification The upstream end of the off-gas supply pipe 102 to which the off-gas separated by the container 90 is delivered 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 impurities adsorbed on the adsorbent, Next, the desorption process is performed in one adsorption tank, and the adsorption process is performed in the other adsorption tank. By repeating this periodically, the reformed gas G3 is continuously separated into hydrogen and impurities containing carbon monoxide (off gas OG), and hydrogen is purified. The purified hydrogen is sent to the hydrogen supply pipe 92 and can be stored in a tank (not shown) or sent to the hydrogen supply line.

The off gas of the hydrogen purifier 90 can be supplied to a flare stack 100 described later via an off gas supply pipe 102.

(Combustion exhaust gas water separation section)
A downstream end of a gas exhaust pipe 28 that guides the combustion exhaust gas from the combustion exhaust gas flow path 27 of the reformer 12 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 into the outside air.

The downstream ends of the water recovery pipes 59, 69, and 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. For example, pure water or city water is supplied from the external water supply unit 17 to the reforming water supply pipe 34.

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.

<flare stack>
The flare stack 100 is connected to the downstream end of an offgas supply pipe 102, and is also connected to an air supply pipe 104 for introducing air from the outside. The offgas supply pipe 102 corresponds to the “offgas flow path”.

The flare stack 100 has a frame holder (not shown) whose one end is open. Offgas and air are supplied from the offgas supply pipe 102 and the air supply pipe 104 into the frame holder to form a mixed gas, which is ignited by an igniter (not shown). By doing so, it is possible to burn in the state of being exposed to the outside air.

That is, in the flare stack 100, the off gas is combusted and discharged as a combustion exhaust gas into the outside air.

(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. In the reforming catalyst layer 36, heat from the combustion exhaust gas flowing through the combustion exhaust gas passage 27 is received, and a reforming gas containing hydrogen as a main component is generated from the mixed gas by the steam reforming reaction. This reformed gas is supplied to the CO shift catalyst layer 45 through the reformed gas flow path 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 oxidant gas supply pipe 46, and carbon monoxide is converted into oxygen on the precious metal catalyst. Reacts with and is converted to carbon dioxide to remove carbon monoxide. 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.

At this time, in the combustion chamber 25 of the multi-cylinder reformer 12, the burner 26 combusts a gas obtained by mixing the city gas and air supplied from the raw material branch pipe 33A and the air branch pipe 40A. The combustion exhaust gas is supplied from the combustion chamber 25 to the combustion exhaust gas water separation unit 70 via the combustion exhaust gas passage 27 and the gas exhaust pipe 28. 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 78. The combustion exhaust gas from which the water has been separated is discharged from the gas discharge pipe 76 into the outside air.

On the other hand, 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 to the water separation unit 60 after pressurization from the communication flow path pipe 66. In the post-pressurization water separation unit 60, the 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 the water has been separated is supplied to the hydrogen purifier 90 from the communication flow path pipe 68.

The water sent from the pre-pressurization 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 59, 69, and 78 is returned to the reforming water supply pipe 34. By driving the pump P1, the reforming water supply pipe 34 supplies the reforming water to the multi-cylinder reformer 12.

The hydrogen purifier 90 employs a pressure swing method, in which one of the pair of adsorption tanks adsorbs impurities other than hydrogen in the adsorbent, and the other adsorption tank desorbs the impurities adsorbed in the adsorbent. .. In the hydrogen purifier 90, the adsorption step and the desorption step are repeated in each adsorption tank at a constant cycle to continuously separate hydrogen and impurities from the reformed gas G3 to purify hydrogen.

Hydrogen as a product purified by the hydrogen purifier 90 is sent to the hydrogen supply pipe 92, stored in a tank (not shown), or sent to the hydrogen supply line.

On the other hand, the offgas OG discharged from the hydrogen purifier 90 is supplied to the flare stack 100 via the offgas supply pipe 102. The offgas OG contains carbon monoxide that could not be completely removed by the reformer 12 and hydrogen that could not be completely separated by the hydrogen purifier 90.

In the flare stack 100, the off gas OG supplied from the off gas supply pipe 102 and the air supplied from the air supply pipe 104 are mixed in a frame holder (not shown) to form a mixed gas, which is ignited by an igniter. The mixed gas is burned. At this time, carbon monoxide contained in the off gas reacts with oxygen and is converted into carbon dioxide. Further, the combustion exhaust gas of the flare stack 100 is discharged into the outside air.

As described above, in the hydrogen production device 10, the offgas OG is supplied from the hydrogen purifier 90 to the flare stack 100. As a result of burning the offgas OG in the flare stack 100, carbon monoxide contained in the offgas OG is converted into carbon dioxide.

That is, the off-gas OG of the hydrogen purifier 90 is discharged to the outside air as combustion exhaust gas after carbon monoxide is removed or reduced by combustion in the flare stack 100.

As described above, in this hydrogen production device 10, the carbon monoxide in the offgas OG can be removed or reduced and discharged to the outside air only by providing the flare stack 100 on the offgas discharge side of the hydrogen purifier 90.

That is, the hydrogen production device 10 can reduce the carbon monoxide concentration of the offgas OG of the hydrogen purifier 90 and discharge it as the combustion exhaust gas into the outside air with a simple configuration.

In particular, when the hydrogen production device 10 is newly installed in a factory or the like, a flare stack may exist as an existing facility. In this case, it suffices to connect the off-gas supply pipe 102 from the hydrogen purifier 90 of the hydrogen production device 10 to the vent gas supply pipe of the existing flare stack. If the flow rate of the vent gas in the existing flare stack is sufficiently higher than the flow rate of the off gas, the off gas monoxide concentration can be reduced only by supplying the off gas to the existing flare stack without controlling the flow rate of the off gas OG. Can be discharged into the open air.

By providing a buffer tank in the middle of the offgas supply pipe 102 and temporarily storing the offgas OG in the buffer tank, for example, when the hydrogen purifier 90 is a PSA device, the flow rate and composition of the offgas that periodically fluctuate are leveled. It is also considered that the flare stack 100 is converted into a material and supplied to the flare stack 100.

[Second Embodiment]
A hydrogen production apparatus 200 according to the second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Further, in the hydrogen production device 200, only the flare stack 100 of the hydrogen production device 10 is replaced with the carbon monoxide selective oxidation part 202, and therefore only the configuration and action relating to that part will be explained, and the same action and effect as the first embodiment. The detailed description will be omitted.

(Constitution)
As shown in FIG. 3, the hydrogen production apparatus 200 is provided with a carbon monoxide selective oxidation unit 202 on the off gas downstream side of the hydrogen purifier 90.

The carbon monoxide selective oxidation unit 202 is provided with an off gas flow passage 204 therein, and a CO selective oxidation catalyst layer 206 is provided in the off gas flow passage 204. In this CO selective oxidation catalyst layer 206, only carbon monoxide selectively reacts with oxygen on a noble metal catalyst such as platinum or ruthenium to be converted into carbon dioxide, and carbon monoxide can be removed.

Further, in the carbon monoxide selective oxidation section 202, an off gas supply pipe 102 communicating with the hydrogen purifier 90 and an air supply pipe 104 for introducing air from the outside air are connected to the upstream side of the off gas flow passage 204. There is. An exhaust pipe 208 is connected to the downstream side of the offgas channel 204. The off-gas supply pipe 102 and the exhaust pipe 208 correspond to “off-gas passage”.

(Action)
In the hydrogen production apparatus 200, the offgas OG discharged from the hydrogen purifier 90 is supplied to the carbon monoxide selective oxidation unit 202 via the offgas supply pipe 102. Further, air is supplied from the air supply pipe 104 to the carbon monoxide selective oxidation unit 202. The off gas supplied to the carbon monoxide selective oxidation unit 202 is supplied to the CO selective oxidation catalyst layer 206 together with air, and only carbon monoxide selectively reacts with oxygen on the noble metal catalyst of the CO selective oxidation catalyst layer 206. It is converted to carbon dioxide and carbon monoxide is removed from the offgas OG. The off gas whose carbon monoxide has been reduced in the CO selective oxidation catalyst layer 206 is exhausted into the outside air as an exhaust gas from the exhaust pipe 208.

Therefore, in the hydrogen production apparatus 200, by providing the carbon monoxide selective oxidation unit 202 on the off gas discharge side of the hydrogen purifier 90, carbon monoxide in the off gas OG can be removed or reduced and discharged to the outside air. That is, with a simple configuration, it is possible to reduce the concentration of carbon monoxide in the offgas OG of the hydrogen purifier 90 and discharge it as an exhaust gas into the outside air.

Further, when the offgas OG of the hydrogen purifier 90 is returned to the reformer 12 (burner 26) in the hydrogen production apparatus 200 as fuel, the hydrogen purity of the product is maintained and the combustion of the burner 26 is maintained in a predetermined state. Therefore, the flow rate control corresponding to the offgas OG in which the pressure (flow rate) and the composition fluctuate periodically becomes complicated.

On the other hand, in the hydrogen production device 200, since the offgas OG is simply passed through the CO selective oxidation catalyst layer 206 of the carbon monoxide selective oxidation part 202 to be reacted, the flow rate control of the offgas OG is unnecessary and the configuration is simple. Become.

That is, the hydrogen production apparatus 10 can reduce the concentration of carbon monoxide of the off gas OG of the hydrogen purifier 90 and discharge it as the exhaust gas into the outside air with a simple structure.

A buffer tank is provided in the middle of the off-gas supply pipe 102, and the off-gas OG is temporarily stored in the buffer tank to equalize the flow rate and composition of the off-gas that periodically fluctuates when the hydrogen purifier 90 is a PSA device. It is also conceivable to supply it to the carbon monoxide selective oxidation unit 202.

[Third Embodiment]
Hydrogen producing apparatuses 300 and 300A according to a third embodiment of the present invention will be described with reference to FIGS. 4 and 5. The same components as those in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the hydrogen producing apparatuses 300 and 300A are different only in that the heat exchanger HE4 is provided on the reforming water supply pipe 34. Therefore, only the configuration and operation relating to the relevant portion will be described, and the first and second embodiments will be described. A detailed description of similar effects will be omitted.

(Constitution)
As shown in FIG. 4, the hydrogen production apparatus 300 is provided with a heat exchanger HE4 for exchanging heat between the reforming water in the reforming water supply pipe 34 and the flare stack 100. That is, the heat exchanger HE4 is configured by disposing the reforming water supply pipe 34 so as to wind the flare stack 100.

(Action)
In the hydrogen production apparatus 300, since the heat exchanger HE4 is formed by winding the flare stack 100 around the reforming water supply pipe 34, the combustion water of the flare stack 100 causes the reforming water in the reforming water supply pipe 34 to be changed. Is heated. As described above, since the reforming water is heated before being supplied to the reformer 12, the amount of heat required when the reforming water is vaporized in the preheating passage 32 of the reformer 12 is reduced. It

That is, the thermal efficiency of the hydrogen production device 300 is improved.

As shown in FIG. 5, in the hydrogen production apparatus 300A, when the flare stack 100 is replaced by the carbon monoxide selective oxidation unit 202, heat exchange is performed at the intersection of the reforming water supply pipe 34 and the exhaust pipe 208. By providing the reactor HE4, the same operational effect as that of the hydrogen production device 300 can be achieved.

That is, since the oxidation reaction of carbon monoxide carried out in the CO selective oxidation catalyst layer 206 is an exothermic reaction, the exhaust gas discharged from the carbon monoxide selective oxidation section 202 via the exhaust pipe 208 becomes higher in temperature than the reforming water. The reforming water is heated by the heat exchange in the heat exchanger HE4, and the same effect is obtained.

[Fourth Embodiment]
A hydrogen production apparatus 400 according to the fourth embodiment of the present invention will be described with reference to FIGS. 1 and 3 to 7. The same components as those in the first and third embodiments are designated by the same reference numerals, and detailed description thereof will be omitted. In addition, since the hydrogen production device 400 is different only in the structure of the reformer 12, only the configuration and operation relating to the relevant portion will be described, and detailed description of the same operation effects as those of the first to third embodiments will be omitted. ..

(Constitution)
As shown in FIG. 6, the reformer 402 of the hydrogen production device 400 is obtained by removing the oxidant gas supply pipe 46 and the CO selective oxidation catalyst layer 47 from the reformer 12 (see FIG. 2). In other words, the reformer 402 is provided with only the CO shift catalyst layer 45 in the second flow path 42.

(Action)
As described above, in the reformer 402 of the hydrogen production apparatus 400, the city gas and the reforming water are mixed gas in the preheating flow path 32, and the mixed gas is supplied to the reforming catalyst layer 36 to perform steam reforming. Thus, the reformed gas G0 containing hydrogen as a main component is obtained. The reformed gas G0 corresponds to the “primary reformed gas”.

By supplying this reformed gas G0 to the CO shift catalyst layer 45 of the second flow path 42, carbon monoxide contained in the reformed gas G0 is converted into carbon dioxide by the aqueous shift reaction. The reformed gas G1 from which the carbon monoxide has been reduced is sent from the reformed gas G0 to the outside of the reformer 402 via the reformed gas discharge pipe 44.

At this time, since the second flow path 42 of the reformer 402 has a configuration without a CO selective oxidation catalyst layer, an oxidant gas supply for introducing an oxidant gas (air) required in the CO selective oxidation catalyst layer is provided. There is no pipe. As a result, in the reformer 402, air is not mixed in the reformed gas G0 that has been steam-reformed in the second flow path 42. That is, carbon monoxide is reduced from the reformed gas G0 in the reformer 402, and the argon contained in the air is prevented from being mixed into the reformed gas G1 sent to the outside.

In this way, since the reforming gas G1 (G3) does not contain argon that is difficult to remove in the hydrogen purifier 90, the purity of the product hydrogen refined in the hydrogen purifier 90 can be improved. Alternatively, since it is not necessary to remove argon from the reformed gas G3 (G1), the load on the hydrogen purifier 90 can be reduced.

In particular, when the carbon monoxide selective oxidation unit 202 is arranged on the downstream side of the hydrogen purifier 90, the purity of the product hydrogen is improved by removing the CO selective oxidation catalyst layer from the inside of the reformer 402, or By reducing the load on the hydrogen purifier 90 and arranging the carbon monoxide selective oxidation unit 202 including the CO selective oxidation catalyst layer 206 thereof on the downstream side of the hydrogen purifier 90, the off gas (exhaust gas) to be discharged. ) It is possible to reduce the carbon monoxide concentration.

As shown in FIG. 7, in the hydrogen production apparatus 400, the CO shift catalyst layer 45 is changed to a reformer 402A in which the arrangement range of the CO shift catalyst layer 45 is increased as compared with the reformer 402. It is also possible to increase the carbon monoxide treatment (removal) capacity.

With such a configuration, the amount of hydrogen contained in the reformed gas G1 increases, so that the amount of hydrogen separated in the hydrogen purifier 90 increases. That is, the amount of product hydrogen extracted from the reformed gas G1 can be increased.

The reformers 402 and 402A described in the present embodiment are applicable to any of the hydrogen production devices 10, 200, 300, and 300A.

[Other]
In the hydrogen production devices 10, 200, 300, 300A, and 400 according to the first to fourth embodiments, the reformers 12, 402, and 402A are multi-tubular reformers, but are not limited thereto. Absent. It is only necessary that the city gas can be reformed into a reformed gas containing hydrogen as a main component.

Further, in the hydrogen production devices 10, 200, 300, 300A, 400 according to the first to fourth embodiments, the case where the hydrogen purifier 90 is a PSA device has been described, but hydrogen can be purified from the reformed gas G3. If so, it is not limited to this.

Furthermore, the carbon monoxide selective oxidation unit 202 according to the second and third embodiments is described as including the CO selective oxidation catalyst layer 206 and selectively oxidizing carbon monoxide in the offgas OG on the metal catalyst. However, it is not limited to this. Even if it does not have the CO selective oxidation catalyst layer 206, it may be one that selectively oxidizes only carbon monoxide in the offgas OG.

Further, although the exhaust pipe 208 is provided in order to discharge the exhaust gas from the carbon monoxide selective oxidation unit 202 to the outside air, it may be provided inside the carbon monoxide selective oxidation unit 202. That is, the carbon monoxide selective oxidation unit 202 may be directly discharged to the outside.

Further, in the flare stack 100 according to the first and third embodiments, the off gas and the air are mixed gas in the frame holder and ignited by the igniter, but the off gas is burned at the downstream end of the off gas supply pipe 102. Other configurations may be used as long as they can be made.

10, 200, 300, 300A, 400 Hydrogen production device 12, 400, 400A Multiple cylinder reformer (reformer)
36 Reforming catalyst layer (reforming section)
42 Second channel (carbon monoxide removal section)
90 hydrogen purifier 100 flare stack 102 off-gas supply pipe (off-gas flow path)
208 Exhaust pipe (off-gas flow path)
202 carbon monoxide selective oxidation part G0 reformed gas (primary reformed gas)
HE4 heat exchanger (heat recovery part)

Claims (3)

A hydrocarbon is supplied as a raw material, and a reformer that reforms the hydrocarbon to generate a reformed gas containing hydrogen as a main component and carbon monoxide,
A hydrogen purifier that is connected to the reformer and separates the reformed gas into product hydrogen and off gas that is an impurity to purify product hydrogen;
An off-gas flow path in which the off-gas discharged from the hydrogen purifier flows, which communicates with the hydrogen purifier and the outside air,
A flare stack provided on the off-gas channel or a carbon monoxide selective oxidation part for selectively oxidizing carbon monoxide,
Hydrogen production device equipped with. A water supply pipe for supplying water as a raw material to the reformer,
A heat recovery unit provided on the water supply pipe, in which the water recovers combustion heat of the flare stack or oxidation reaction heat of the carbon monoxide selective oxidation unit,
The hydrogen production apparatus according to claim 1, further comprising: The reformer reforms the hydrocarbon to generate a primary reformed gas containing hydrogen as a main component;
A carbon monoxide removing unit that generates a reformed gas in which carbon monoxide is reduced from the primary reformed gas only by an aqueous shift reaction and sends the reformed gas to the hydrogen purifier,
The hydrogen production apparatus according to claim 1 or 2, further comprising: