JP6523134B2 - Hydrogen gas production method and hydrogen gas production apparatus - Google Patents

Description

  The present invention relates to a hydrogen gas production method and a hydrogen gas production apparatus.

A steam reformer and a hydrogen pressure swing adsorption (PSA) apparatus are often used to produce high purity hydrogen used as fuel for fuel cells and the like. The steam reformer is an apparatus for producing a hydrogen-rich reformed gas from hydrocarbons such as natural gas, and the hydrogen PSA apparatus is carbon monoxide (CO), methane (CH ₄ ) contained in the reformed gas. It is an apparatus that removes impurities such as carbon dioxide (CO ₂ ) and purifies hydrogen of high purity.

  Since the reaction temperature in the steam reformer is as high as about 800 ° C. and the steam reforming reaction is an endothermic reaction, the steam reformer needs to supply heat from the outside. As a heat source of the steam reformer, a part of a raw material gas such as natural gas or an off gas exhausted from a hydrogen PSA apparatus is used. As described above, by using the off gas as a heat source of the steam reformer, the supply amount of the source gas can be reduced.

  However, when the off-gas discharged from the hydrogen PSA unit is used as a heat source of the steam reformer, since the off-gas contains carbon dioxide which is a nonflammable gas, the sensible heat component of carbon dioxide tends to lower the combustion efficiency. .

  Besides the above-mentioned steam reforming method, there are a partial oxidation reforming method and an autothermal reforming method as a method of producing hydrogen. Since partial oxidation reforming is an exothermic reaction, an external heat source for heating can be unnecessary. Further, autothermal reforming is a method of combining steam reforming and partial oxidation reforming, and a heat source necessary for steam reforming is supplemented with a heat source generated by partial oxidation reforming, so that the heat source can be similarly unnecessary. In such partial oxidation reforming and autothermal reforming, the supply amount of the raw material gas can be reduced by recycling the off gas discharged from the hydrogen PSA device as a part of the reformed gas production raw material, thereby producing hydrogen Cost can be reduced.

  However, when the off-gas discharged from the hydrogen PSA unit is used as a raw material for producing a reformed gas, carbon dioxide which is an inert gas is contained in the off-gas, so the partial pressure of hydrocarbon gas in the raw material gas is lowered. The reaction efficiency in the treatment equipment is reduced. Moreover, when using as a raw material of a reformer, if the off-gas of the hydrogen PSA device containing a large amount of carbon dioxide is introduced, the carbon dioxide partial pressure in the reformed gas is increased, and the carbon dioxide is removed in the hydrogen PSA device. The load on the For this reason, while the adsorption tower size becomes large, the hydrogen recovery rate tends to decrease.

  The present inventors have proposed a hydrogen PSA device which is excellent in hydrogen recovery rate and leads to reduction of hydrogen production cost in Japanese Patent No. 5314408 and Japanese Patent No. 4814024. However, when the hydrogen recovery rate in the hydrogen PSA unit increases, the amount of hydrogen in the off gas of the hydrogen PSA unit decreases, the heating efficiency decreases when recycling the off gas as fuel, and the improvement when recycling as a reformer raw material The increase in carbon dioxide partial pressure in the quality gas becomes significant. For this reason, there is room for improvement in the reduction effect of hydrogen production cost by recycling.

Patent No. 5314408 gazette Patent No. 4814024 gazette

  The present invention has been made based on the above-mentioned circumstances, and reduces the production cost of hydrogen by reducing carbon dioxide in the off gas so that it can be suitably used as a heat source or source gas of a reformer. It is an object of the present invention to provide a hydrogen gas production method and a hydrogen production apparatus that can be produced.

  The present invention, which has been made to solve the above problems, includes a reformer that generates a hydrogen-rich reformed gas by steam reforming, partial oxidation reforming or autothermal reforming of a hydrocarbon-containing gas, and the reformed gas A hydrogen gas production method for producing high purity hydrogen gas using a hydrogen PSA device for removing gases other than hydrogen from the off gas discharged from the hydrogen PSA device using an off gas adsorption tower and carbon dioxide And removing the carbon dioxide in the carbon dioxide removing step, and using the off gas as a heat source or a source gas.

  According to the hydrogen gas production method, since the off gas is used as the heat source or the source gas of the reformer, the supply amount of the source gas can be reduced. Further, since the hydrogen gas production method includes the step of removing carbon dioxide from the off gas, the combustion efficiency when using the off gas as a heat source and the hydrogen recovery rate when using the off gas as a source gas are improved. As a result, since the production efficiency of the product gas with respect to the supply amount of the source gas is improved, the hydrogen production cost can be reduced by using the hydrogen gas production method.

  The reforming of the hydrocarbon-containing gas may be steam reforming, and the off gas may be supplied as a heating fuel for the reformer in the off gas utilization step. As described above, when the reforming of the hydrocarbon-containing gas is steam reforming, the offgas utilized in the offgas utilizing step is supplied as the heating fuel with the offgas whose combustion efficiency is improved, thereby producing the product gas with respect to the supply amount of the raw material gas. Efficiency is further improved.

  The reforming of the hydrocarbon-containing gas is autothermal reforming, and the offgas may be used as a fuel for generating steam to be supplied to the reformer in the offgas utilization step. As described above, when the reforming of the hydrocarbon-containing gas is autothermal reforming, the offgas with improved combustion efficiency is supplied as a fuel for generation of steam in the offgas utilization step, whereby the amount of the raw material gas supplied can be reduced. Product gas production efficiency is further improved.

  The reforming of the hydrocarbon-containing gas may be partial oxidation reforming or autothermal reforming, and the off gas may be supplied as a source gas to the reformer in the off gas utilization step. As described above, when the reforming of the hydrocarbon-containing gas is partial oxidation reforming or autothermal reforming, the raw material is supplied by supplying the off gas as a reformed gas production raw material having a low carbon dioxide concentration in the off gas utilization step. Since the gas supply amount can be reduced, the production efficiency of the product gas with respect to the supply amount of the source gas is further improved.

  It is preferable that the above-described adsorption tower for off gas be filled with activated carbon as an adsorbent for off gas which selectively adsorbs carbon dioxide. By thus setting the offgas adsorbent as activated carbon having a large adsorption capacity of carbon dioxide, the size of the offgas adsorption tower can be reduced, so that the installation cost of the offgas adsorption tower can be reduced.

  It is preferable that the above-described adsorption tower for off gas be further filled with a moisture removing adsorbent. As described above, by charging the adsorbent for removing water into the adsorption tower for off gas, it is possible to suppress the decrease of the carbon dioxide adsorption capacity of the activated carbon due to the adsorption of the water on the activated carbon.

  The hydrogen PSA unit may include an adsorption tower packed with an adsorbent that selectively adsorbs carbon monoxide. As described above, the hydrogen PSA device has an adsorption tower packed with an adsorbent that selectively adsorbs carbon monoxide, whereby the adsorbent loading amount for removing carbon monoxide in the reformed gas is reduced to zeolite or the like. Since the amount can be significantly reduced as compared to the case of use, the size of the adsorption tower can be reduced and the hydrogen recovery rate can be improved.

  A material in which the above-mentioned adsorbent which selectively adsorbs carbon monoxide supports copper (I) halide or copper (II) halide supported on at least one of porous silica, porous alumina and polystyrene. It is preferable to use a material obtained by reducing this material or a material obtained by ion exchange of cations in zeolite to monovalent copper (Cu (I)). Since the above-mentioned material has a large adsorption capacity of carbon monoxide, by using an adsorbent which selectively adsorbs carbon monoxide as the main component, the amount of the adsorbent used can be further reduced and hydrogen is recovered. Rate can be improved. In addition, a "main component" means the component with most content, for example, the component contained 50 mass% or more.

  It is preferable that the hydrogen PSA device is a vacuum regeneration hydrogen PSA device that performs a pressure reduction operation below normal pressure during regeneration of the adsorbent. As described above, by using the vacuum regeneration hydrogen PSA apparatus, the regeneration process of the hydrogen PSA apparatus can be easily performed.

  The hydrogen PSA unit may have a suction pump for reducing the pressure of the adsorption column of the hydrogen PSA unit to atmospheric pressure or lower. As described above, since the hydrogen PSA unit has a suction pump for reducing the pressure of the adsorption column of the hydrogen PSA unit to the atmospheric pressure or less, the adsorption tower of the hydrogen PSA unit can be easily regenerated.

  It is preferable to further include a step of regenerating the offgas adsorbent by reducing the pressure of the offgas adsorption tower by the suction pump of the hydrogen PSA device. Thus, by reducing the pressure of the adsorption tower for off gas with the suction pump of the hydrogen PSA device to regenerate the adsorbent for off gas, it is possible to reduce the installation cost and operation cost of the off gas PSA device for removing carbon dioxide in the off gas.

  The off-gas adsorbent regeneration step may be performed when the suction pump is not operating in the hydrogen PSA device. By thus performing the off-gas adsorbent regeneration process with the hydrogen PSA device when the suction pump is not operating, the operating efficiency can be improved.

  The adsorbent regeneration step may be performed in another offgas adsorption tower while the carbon dioxide removal step is performed in one offgas adsorption tower using a plurality of the offgas adsorption towers. Thus, by performing the adsorbent regeneration step in the other off gas adsorption tower while performing the carbon dioxide removal step in the one off gas adsorption tower, the carbon dioxide in the off gas is continuously removed to perform the removal per unit time. The offgas throughput can be increased. As a result, the supply amount of source gas can be further reduced.

  In the carbon dioxide removing step, it is preferable to remove carbon dioxide of the off gas under normal temperature and normal pressure. Thus, the removal of carbon dioxide of the off gas using the adsorption tower for off gas is performed at normal temperature and normal pressure, so that the combustion efficiency at the time of using the off gas as a heat source and the hydrogen recovery rate at the time of using the off gas as source gas It can improve. Here, the “normal temperature” is, for example, 0 ° C. or more and 40 ° C. or less. Further, "atmospheric pressure" is a pressure when neither depressurization nor pressurization is performed, and is usually a pressure equal to atmospheric pressure (about 1 atm).

  It is preferable to further include a step of temporarily storing the off gas from which the carbon dioxide has been removed in the carbon dioxide removal step. By thus temporarily storing the off gas from which carbon dioxide has been removed, it is possible to adjust the supply amount and pressure of the off gas from which carbon dioxide is removed to the reformer, etc., the off gas from which carbon dioxide is removed is stabilized. Can be supplied to the reformer.

  Another invention made to solve the above problems is a reformer that generates a hydrogen-rich reformed gas by steam reforming, partial oxidation reforming or autothermal reforming of a hydrocarbon-containing gas, and An offgas adsorption tower for removing hydrogen gas from a reformed gas comprising a hydrogen PSA unit for removing a gas other than hydrogen and removing carbon dioxide from the offgas discharged from the hydrogen PSA unit; And an off gas utilization line that uses the off gas from which carbon dioxide has been removed by the tower as a heat source or a source gas.

  Since the said hydrogen production apparatus can use off gas as a heat source or source gas of a reformer by the off gas utilization line which utilizes off gas as a heat source or source gas, it can reduce supply_amount | feed_rate of source gas. Further, since the hydrogen production apparatus is equipped with an off-gas adsorption tower, carbon dioxide which is an inert gas can be removed from the off-gas discharged from the hydrogen PSA apparatus, and the combustion efficiency and off-gas when using the off gas as a heat source The hydrogen recovery rate when used as a source gas is improved. As a result, since the production efficiency of the product gas is improved, the hydrogen production apparatus can reduce the hydrogen production cost.

  As described above, according to the hydrogen gas production method and the hydrogen production apparatus of the present invention, the combustion efficiency of the off gas used as the heat source of the reformer is improved, or the off gas is recycled as part of the source gas. As a result, the supply amount of fuel gas, raw material gas and the like to the product hydrogen gas can be reduced, and the hydrogen production cost can be reduced.

It is a flowchart which shows the hydrogen gas production process of the hydrogen production apparatus by steam reforming which concerns on one Embodiment of this invention. It is a flowchart which shows the hydrogen gas production process of the hydrogen production apparatus by auto thermal reforming which concerns on one Embodiment of this invention. It is the schematic which shows the hydrogen PSA apparatus of FIG.1 and FIG.2, and an off gas PSA apparatus. It is a flowchart which shows the hydrogen gas production process of the hydrogen production apparatus by steam reforming in a comparative example.

  Hereinafter, embodiments of the hydrogen production apparatus and the hydrogen gas production method of the present invention will be described in detail with reference to the drawings as appropriate.

[Hydrogen production equipment]
The hydrogen production apparatus shown in FIG. 1 includes a reformer 1 that generates a hydrogen-rich reformed gas B by steam reforming of a hydrocarbon gas that is a raw material gas A, and removes gases other than hydrogen in the reformed gas B. And an off-gas PSA unit 3 for removing carbon dioxide of the off-gas C discharged from the hydrogen PSA unit 2.

  Further, in the hydrogen production apparatus of FIG. 2, a reformer 1 a that generates a hydrogen-rich reformed gas B by autothermal reforming of a hydrocarbon gas that is a source gas A, and hydrogen other than hydrogen in the reformed gas B A hydrogen PSA unit 2 for removing gas and an off gas PSA unit 3 for removing carbon dioxide of the off gas C discharged from the hydrogen PSA unit 2 are provided.

<Reformer>
As the steam reformer 1 of FIG. 1, for example, a reformer in which a known steam reforming unit and a metamorphic unit are combined can be used. The hydrogen-rich reformed gas B is obtained by subjecting the raw material gas A to steam reforming by the reformer 1 to which the raw material gas A and water H containing hydrocarbons such as natural gas are supplied. Specifically, the raw material gas A containing hydrocarbon is reformed by steam by the reforming reaction in the steam reforming section, and after being converted to gas mainly composed of hydrogen and carbon monoxide, it is further reformed by the shift section. The carbon monoxide in the quality gas is transformed with steam to produce a hydrogen-rich reformed gas B. The reformed gas B contains, in addition to hydrogen, impurities such as unreacted natural gas components such as carbon monoxide, carbon dioxide and methane, and water. Since the steam reforming reaction is an endothermic reaction, the reformer burner 4 heats the reformer 1 to promote the reaction.

  The autothermal reformer 1a in FIG. 2 is at least partially filled with a reforming catalyst. The autothermal reformer 1a contacts a mixture of a raw material gas and steam with the reforming catalyst to form a reformed gas containing hydrogen as a main component by a reforming reaction, and at least a part of which is oxidized The reformer is provided with a catalyst and is provided with an oxidation exothermic layer which oxidizes a raw material gas for oxidation to generate heat. By supplying the raw material gas A containing hydrocarbons such as natural gas, steam I and oxygen J to the reformer 1a, the raw material gas A is reformed to obtain a reformed gas B. The reformed gas B contains not only hydrogen but also impurities such as unreacted natural gas components such as carbon monoxide, carbon dioxide and methane, and water as well as steam reforming. In the autothermal reforming reaction, the supply of oxygen simultaneously causes the steam reforming reaction and the exothermic reaction due to the oxidation reaction of the raw material to occur simultaneously, so there is no need to heat the reformer 1a from the outside.

(Reformer burner)
As a fuel for the reformer burner 4 used in the steam reformer 1 of FIG. 1, a part of the raw material gas A and a CO ₂ removing off gas D supplied from the off gas PSA device 3 described later are used. The reformer 1 heats the reformer 1 by mixing the raw material gas A and the CO ₂ removal off gas D with the air G and burning them by the reformer burner 4.

  The lower limit of the heating temperature of the steam reformer 1 is not particularly limited, but when the raw material gas A is a natural gas, 700 ° C. is preferable, and 750 ° C. is more preferable. As a maximum of heating temperature, 900 ° C is preferred and 850 ° C is more preferred. If the heating temperature is less than the above lower limit, the efficiency of the steam reforming reaction may decrease, and the catalyst performance may decrease due to carbon deposition of the raw material gas. Moreover, also when the said heating temperature exceeds the said upper limit, there exists a possibility that the fall of the efficiency of steam reforming reaction and the fall of the catalyst performance by carbon deposition of source gas may arise. As said catalyst, a ruthenium type and a nickel type catalyst can be mentioned, for example.

  The source gas A can be appropriately selected and used from a compound containing carbon and hydrogen in the molecule or a mixture thereof. The above compounds may contain other elements such as oxygen. When the raw material of the raw material gas A is a liquid, it may be vaporized by a vaporizer. Specifically, for example, hydrocarbon fuels such as methane, ethane, propane, butane, natural gas, LPG (liquefied petroleum gas), gasoline, naphtha, kerosene and light oil, alcohols such as methanol and ethanol, ethers such as dimethyl ether, etc. It can be mentioned. Among these, natural gas and LPG can be suitably used in view of cost and the like.

<Hydrogen PSA unit>
The hydrogen PSA apparatus 2 shown in FIG. 3 communicates with the three adsorption towers 11a, 11b and 11c for adsorbing and removing specific components in the reformed gas B by the pressure swing adsorption method, and the three adsorption towers 11a, 11b and 11c. A reformed gas supply line 101, a product gas discharge line 201, an adsorption tower pressure reduction line 103, an off gas discharge line 104, a suction pump 12 disposed in the adsorption tower pressure reduction line 103, an adsorption tower pressure reduction line 103 and an off gas discharge line And a connection line 105 for connecting to the connection line 104. The hydrogen PSA device 2 is a vacuum regeneration system that performs a pressure reduction operation below atmospheric pressure at the time of regeneration of the adsorbent.

  The hydrogen PSA apparatus 2 removes impurities other than hydrogen contained in the reformed gas B generated by the reformer 1 or the reformer 1 a, and obtains high purity hydrogen gas as the product gas E. The method for obtaining the high purity product gas E by the hydrogen PSA unit 2 will be described below.

  The reformed gas B is supplied to the three adsorption towers 11 a, 11 b and 11 c through the reformed gas supply line 101.

  The three adsorption towers 11a, 11b and 11c are filled with an adsorbent that adsorbs the above-mentioned impurities in the reformed gas B, and discharge the product gas E of high purity from the product gas discharge line 201. The adsorption towers 11a, 11b, and 11c are operated by sequentially switching a series of processes of adsorption, pressure reduction, pressure equalization and washing, pressure increase, and adsorption. The adsorbed impurities are removed and the adsorbent is regenerated by the steps of reducing the pressure in the adsorption column and the step of washing with hydrogen gas which is the product gas E. After that, the adsorbent which has regenerated the adsorbent is again pressurized and subjected to hydrogen purification again. During the operation of the hydrogen PSA apparatus 2, the adsorption and regeneration can be performed simultaneously in different adsorption towers by shifting the timing of the above series of steps in each adsorption tower so that one of the adsorption towers becomes an adsorption step. The product gas E can be produced continuously.

  The adsorption towers 11a, 11b, 11c are packed with an adsorbent capable of adsorbing carbon monoxide, carbon dioxide methane, which is the main impurities in the reformed gas B, and water. The adsorbent is not particularly limited as long as each impurity can be adsorbed by PSA. Examples of such an adsorbent include 5A-type zeolite which specifically adsorbs carbon monoxide, carbon-based adsorbents which particularly adsorb carbon dioxide and methane, and activated alumina which adsorbs water in particular. These adsorbents are loaded into the adsorption towers 11a, 11b and 11c alone or in combination. In addition, as an adsorbent (CO adsorbent) that selectively adsorbs carbon monoxide, it is possible to use copper (I) halide or copper halide (one or more of porous silica, porous alumina, and polystyrene) as an adsorbent (CO adsorbent). It is preferable to use a material on which II) is supported, a material obtained by reducing this material, or a material in which the cation in the zeolite is ion-exchanged to monovalent copper (Cu (I)) as the main component. These CO adsorbents can significantly reduce the adsorbent loading for removing CO in the reformed gas B as compared with the case of using other adsorbents such as zeolite, and the adsorption tower size is compact Contributes to the improvement of hydrogen and hydrogen recovery rate.

  Further, as an adsorbent to be packed into the adsorption towers 11a, 11b and 11c, an adsorbent capable of adsorbing carbon dioxide is packed together with the above-mentioned CO adsorbent which selectively adsorbs carbon monoxide. As an adsorbent that adsorbs carbon dioxide, a carbon-based adsorbent having a large carbon dioxide adsorption capacity can be suitably used. As a carbon adsorbent, for example, activated carbon or CMS (carbon molecular sieve) can be used, and in particular, activated carbon is preferable in view of low cost.

  The reformed gas supply line 101 is a line for introducing the reformed gas B into the adsorption towers 11a, 11b and 11c. The reforming gas supply line 101 and the three adsorption towers 11a, 11b, and 11c are connected via reforming gas supply valves V1a, V1b, and V1c, respectively.

  The product gas discharge line 201 is a recovery line of the product gas E obtained by removing the impurities of the reformed gas B by the adsorption towers 11a, 11b and 11c, and the three adsorption towers 11a, 11b and 11c respectively discharge the product gas It is connected via the valves V2a, V2b, V2c. The recovered product gas E is temporarily stored in the product gas buffer tank 13 and appropriately supplied. The product gas E is also used as a cleaning gas for the adsorption towers 11a, 11b and 11c.

  In addition to the product gas discharge line 201, a pressure equalizing line 202 and a cleaning line 203 are connected to the discharge side of the adsorption towers 11a, 11b, 11c. The pressure equalizing line 202 is connected to the respective adsorption towers 11a, 11b and 11c via pressure equalizing valves V4a, V4b and V4c, and the washing line 203 is connected to the adsorption towers 11a, 11b and 11c with washing valves V5a, V5b and V5c, respectively. Connected through. While collecting product gas E from one adsorption tower by these product gas discharge line 201, pressure equalization line 202 and washing line 203, supply the product gas E from the remaining adsorption towers to the other adsorption tower And pressure equalization and cleaning steps can be performed.

  The adsorption tower depressurization line 103 and the off gas discharge line 104 are lines used to reduce the pressure in the adsorption tower during regeneration of the adsorption towers 11a, 11b and 11c. The adsorption tower depressurization line 103 and the off gas discharge line 104 are connected via three adsorption towers 11a, 11b and 11c and off gas discharge valves V3a, V3b and V3c, respectively. The suction side of a suction pump 12 for reducing the pressure to below the atmospheric pressure during regeneration of the adsorption towers 11a, 11b and 11c is connected to the adsorption tower depressurization line 103 via a suction pump connection valve V8. The off-gas PSA device 3 is connected to the adsorption tower depressurization line 103 and the off-gas discharge line 104.

  Further, the atmosphere open line 102 is connected to the discharge side of the suction pump 12 of the adsorption column depressurization line 103, and adsorption is performed by opening the atmosphere open valve V7 and the pressure reduction control valve V9 of the off gas PSA device 3 connected to the off gas exhaust line 104. The inside of the tower is open to the atmosphere.

  The off gas C including the specific components and the like of the adsorption towers 11a, 11b and 11c discharged from the off gas discharge line 104 is supplied to the off gas PSA device 3 via the pressure reduction control valve V9 and the off gas tank supply valve V10. Further, the off gas C discharged from the suction pump 12 when the pressure in the adsorption towers 11 a, 11 b and 11 c is reduced is supplied to the off gas PSA device 3 via the connection line 105.

<Off-gas PSA system>
The off-gas PSA apparatus 3 of FIGS. 1 and 2 includes an off-gas tank 14 for storing the off-gas C discharged from the hydrogen PSA apparatus 2 and an off-gas adsorption tower 15 a for removing carbon dioxide from the off-gas C supplied from the off-gas tank 14. , 15b, and an off gas utilization line 303 for supplying a CO ₂ removing off gas D from which carbon dioxide has been removed by the off gas adsorption towers 15a and 15 b to a reformer or the like. Also, off-gas PSA unit 3 is provided with a CO ₂ removal offgas buffer tank 16 for storing offgas adsorption tower 15a, the CO ₂ removal offgas D carbon dioxide has been removed using 15b time. The above off gas adsorption towers 15a and 15b are filled with an off gas adsorbent for adsorbing carbon dioxide and a water removal adsorbent for adsorbing water.

The off gas supply line 301 connected to the off gas tank 14 and the two off gas adsorption towers 15a and 15b are connected via the off gas supply valves V12a and V12b, respectively. In addition, the CO ₂ removal off gas discharge line 302 connected to the CO ₂ removal off gas buffer tank 16 and the two off gas adsorption towers 15 a and 15 b are connected via the CO ₂ removal off gas discharge valves V 13 a and V 13 b, respectively. The off-gas adsorption tower depressurization line 304 connected to the adsorption tower depressurization line 103 of the hydrogen PSA device 2 and the two off-gas adsorption towers 15a and 15b are connected via exhaust gas discharge valves V14a and V14b, respectively.

(Off gas tank)
The off gas tank 14 temporarily stores the off gas C discharged from the hydrogen PSA apparatus 2 in the pressure reduction step and the washing step, and supplies the off gas C from the off gas supply line 301 to the off gas adsorption towers 15a and 15b.

  The off gas C stored in the off gas tank 14 is a gas mainly containing carbon monoxide, carbon dioxide and methane adsorbed by the adsorption towers 11a, 11b and 11c, and hydrogen of the product gas E circulated in the washing step. The components of the off gas C are, for example, 50% by volume of carbon dioxide, 40% by volume of hydrogen, and the remaining 10% by volume.

(Adsorption tower for off gas)
The off gas adsorption towers 15a and 15b are filled with an off gas adsorbent for adsorbing carbon dioxide and a water removal adsorbent for adsorbing water, and at least one of the carbon dioxide in the off gas C supplied from the off gas tank 14 The part and the water are removed by adsorption, and the CO ₂ removed off gas D used as a heat source of the reformer or as a raw material gas is purified.

  As the above off-gas adsorbent, a carbon-based adsorbent capable of selectively adsorbing carbon dioxide is preferable. For example, activated carbon and CMS (carbon molecular sieve) can be used. In particular, activated carbon is preferable in terms of cost. As the water removing adsorbent, for example, activated alumina and silica gel are suitable.

  The role of the adsorption tower for off-gas is to enhance the combustion efficiency of off-gas and to use it as a raw material by removing the carbon dioxide when recycling the off-gas and using it as a heating fuel for the reformer or a raw material for the reformer. The purpose is to prevent carbon dioxide contamination in the raw materials of However, in the adsorption tower for off-gas, it is not necessary to remove all carbon dioxide in the off-gas, and it is possible to expect an effect in recycling only by removing a part of carbon dioxide in the off-gas. When removing all the carbon dioxide in the off gas, the mass ratio of the adsorbent for carbon dioxide for off-gas packed in one adsorption tower for off-gas to the adsorbent for carbon dioxide charged in one adsorption tower of hydrogen PSA unit 2 As a lower limit of, 0.6 is preferable and 0.7 is more preferable. By charging the adsorbent for carbon dioxide in the above mass ratio to the adsorption tower for off gas, carbon dioxide in the off gas can be almost completely removed.

(Off gas utilization line)
The off gas utilization line 303 is a pipe that uses the off gas from which carbon dioxide has been removed as a heat source or a source gas. In the case of the steam reformer 1 of FIG. 1, a CO ₂ removal off gas D is supplied to the reformer burner 4 as a heat source. Further, in the case of the auto thermal reformer 1 a of FIG. 2, the CO ₂ removal off gas D is supplied to the steam generator as a fuel for generating steam supplied to the reformer. Furthermore, in the case of the auto thermal reformer 1a of FIG. 2, the CO ₂ removal off gas D may be supplied to the reformer as a source gas.

(CO ₂ removal off gas buffer tank)
The CO ₂ removal off gas buffer tank 16 temporarily stores the CO ₂ removal off gas D from which carbon dioxide has been removed from the off gas C by the off gas adsorption towers 15 a and 15 b. By providing the CO ₂ removal off gas buffer tank 16, the CO ₂ removal off gas D can be supplied to the reformer burner 4 or the like as appropriate. Free Further, by providing the CO ₂ removing offgas buffer tank 16, it is possible to adjust the flow rate of the CO ₂ removal offgas D, increases the flexibility of the offgas adsorption tower 15a, 15b of the design, when designing the plant The offgas adsorption towers 15a and 15b can be installed in consideration of the region and the like.

[Hydrogen gas production method]
Next, the hydrogen gas production method will be described using the hydrogen production apparatus of FIG.

  The hydrogen gas production method includes a step of generating a hydrogen-rich reformed gas B by steam reforming of a hydrocarbon-containing gas in the reformer 1, and a reformed gas generated in the reformer 1 from the hydrogen PSA device 2. The step of removing the gas other than hydrogen in B, the step of storing the off gas C discharged from the hydrogen PSA apparatus 2 in the off gas tank 14, and the off gas tank 14 using the off gas adsorption towers 15a and 15b The step of removing carbon dioxide from the off gas C, the step of regenerating the off gas adsorbent by reducing the pressure of the off gas adsorption towers 15a and 15b by the suction pump 12 of the hydrogen PSA device 2, the carbon dioxide in the carbon dioxide removing step Supplying the removed off gas D to the reformer 1 as a heat source.

(Reforming gas generation process)
In the reformed gas generation step, the reformer 1 is supplied with a source gas A such as natural gas and water H. The reformer 1 has a steam reforming unit and a shift unit, and the steam reforming unit has a steam generator and a catalyst. The steam reforming unit causes a steam reforming reaction of the following formula (1) to occur using a catalyst between the steam supplied from the steam generator and the raw material gas A to obtain a hydrogen-containing gas.
C _n H _m + _n H ₂ O → n CO + (n + m / 2) H ₂ (1)

  Since this steam reforming reaction is an endothermic reaction, the reaction is promoted by heating by the reformer burner 4 so that the atmosphere in the reformer 1 reaches the reforming temperature. As a catalyst of the said steam reforming part, the catalyst of a ruthenium type and a nickel type can be mentioned, for example.

The shift section has a catalyst, and the shift reaction of the following formula (2) is caused by the catalyst by the steam and carbon monoxide in the hydrogen-containing gas obtained by the above steam reforming section to produce a hydrogen-rich reformed gas Generate B.
CO + H ₂ O → CO ₂ + H ₂ (2)

  Examples of the catalyst in the above-mentioned shift portion include iron-chromium catalysts and copper-zinc catalysts. The atmosphere temperature in the shift section, that is, the shift reaction temperature is preferably 320 ° C. or more and 450 ° C. or less in the case of iron / chromium-based catalyst, and 150 ° C. or more and 300 ° C. or less in the case of copper / zinc-based catalyst . The reformed gas B obtained in this manner is sent to the hydrogen PSA apparatus 2 in a pressurized state.

(Impurity removal process by hydrogen PSA device)
In the impurity removal step of removing gas other than hydrogen in the reformed gas B, the hydrogen PSA device 2 is used to adsorb and remove specific components in the reformed gas B by pressure swing adsorption. In this adsorption removal method, the adsorption removal step of the specific component is performed in one of the three adsorption towers 11a, 11b, 11c, and the adsorbent regeneration process by the pressure reduction in the suction pump 12 in the remaining adsorption towers in the meantime. I do. In this case, while performing the adsorption removal step in the first adsorption tower 11a for these steps using Table 1, the regeneration step is performed in the second adsorption tower 11b and the third adsorption tower 11c. This will be specifically described taking the example.

(Step 0)
In the state immediately before step 1 (step 0), the reformed gas B is supplied to the first adsorption column 11a, and the product gas E from which impurities have been removed passes through the product gas discharge valve V2a of the first adsorption column 11a. The second adsorption column 11b is recovered from the gas discharge line 201, and is in a negative pressure state immediately after the cleaning with the product gas E in the regeneration step is finished, and the third adsorption column 11c is just after the adsorption removal step is finished It is in a pressurized state.

(Step 1)
From the state of Step 0, first, pressure equalization of the second adsorption tower 11b and the third adsorption tower 11c is performed. In this pressure equalization step, the pressure equalizing valve V4b of the second adsorption tower 11b and the pressure equalizing valve V4c of the third adsorption tower 11c are opened to connect the second adsorption tower 11b and the third adsorption tower 11c. Thus, the gas in the third adsorption column 11c is transferred to the second adsorption column 11b to equalize the internal pressure of the second adsorption column 11b and the internal pressure of the third adsorption column 11c. At this time, the pressure in the second adsorption column 11b is increased, and the pressure in the third adsorption column 11c is reduced.

(Step 2)
The third adsorption tower 11c is closed by closing the pressure equalizing valve V4c of the third adsorption tower 11c and discharging the gas in the third adsorption tower 11c by opening the off gas discharge valve V3c, the pressure reduction control valve V9 and the atmosphere open valve V7. Primary pressure reduction to atmospheric pressure. At this time, by opening the buffer tank connection valve V6, the product gas E is supplied from the product gas buffer tank 13 to the second adsorption column 11b, and the pressure is increased. The pressure increase of the second adsorption tower 11b is continued until the adsorption pressure is reached.

(Step 3)
The pressure reduction control valve V9 is closed, the suction pump connection valve V8 is opened, and the suction pump 12 is driven to suck the gas in the third adsorption column 11c to further reduce the pressure of the third adsorption column 11c from the atmospheric pressure. At this time, the off gas C discharged from the suction pump 12 is supplied to the off gas tank 14 of the off gas PSA device 3 by closing the air release valve V7 and opening the off gas tank supply valve V10.

(Step 4)
With the pressure in the third adsorption column 11c sufficiently lowered, the off gas exhaust valve V3c of the third adsorption column 11c is closed and the cleaning valve V5c is opened to introduce the product gas E into the third adsorption column 11c. The adsorbent is washed and regenerated. At this time, although the pressure in the third adsorption column 11c is increased by the introduction of the product gas E, the pressure in the third adsorption column 11c is maintained at a pressure less than the atmospheric pressure by continuing the pressure reduction by the suction pump 12. The lower the pressure in the adsorption column during washing, the better.

(After step 5)
When the regeneration process of the third adsorption column 11c is completed, the suction pump 12 is stopped, and the adsorption towers that perform adsorption removal are switched to the second adsorption column 11b by operating the respective valves, and the regeneration of the third adsorption column 11c While continuing the pressure increase in the process, the regeneration process of the first adsorption tower 11a is started. The subsequent steps are repeated while replacing the adsorption towers performing the adsorption removal step and the regeneration step. By such an adsorption removal method, it becomes possible to perform adsorption and regeneration simultaneously in different adsorption towers, and product gas E can be produced continuously.

(Off-gas storage process)
In the off gas storage process, the off gas C discharged in the depressurization process and the cleaning process of the hydrogen PSA device 2 is temporarily stored in the off gas tank 14.

  As described above, during the depressurization process and the cleaning process of the hydrogen PSA device 2, the offgas tank discharged from the suction pump 12 is closed by closing the air release valve V7 and opening the offgas tank supply valve V10. Supply into 14. The off gas C in the pressure reduction step mainly contains carbon monoxide, carbon dioxide, methane and water adsorbed by the adsorption towers 11a, 11b and 11c. On the other hand, since the product gas E is made to flow through the adsorption towers 11a, 11b and 11c in the cleaning step, the off gas C in the cleaning step contains a large amount of hydrogen.

(CO2 removal process by off-gas PSA system)
The off-gas PSA apparatus 3 includes two off-gas adsorption towers 15a and 15b, and one of the off-gas adsorption towers performs a carbon dioxide removal process, and the other off-gas adsorption tower performs an adsorbent regeneration process. The case where the regeneration process is performed in the second offgas adsorption tower 15b while the adsorption removal process is performed in the first offgas adsorption tower 15a as shown in Table 1 will be specifically described as an example.

(Step 0)
In the state immediately before step 1 (step 0), the offgas C is supplied to the first offgas adsorption tower 15a by closing the exhaust gas discharge valve V14a, and the CO ₂ removal offgas is adsorbed for the first offgas. It is recovered through the CO ₂ removal off gas exhaust valve V 13 a of the column 15 a and stored in the CO ₂ removal off gas buffer tank 16. At this time, the second off-gas adsorption tower 15b is in a state after the adsorption process is completed.

(Step 1 and Step 2)
In the first offgas adsorption tower 15a, the exhaust gas discharge valve V14a of the first offgas adsorption tower 15a, the offgas supply valve V12b of the second offgas adsorption tower 15b, and the CO ₂ removal offgas discharge valve V13b are closed. The off gas tank discharge valve V11, the off gas supply valve V12a of the first off gas adsorption tower 15a, and the CO ₂ removal off gas discharge valve V13a are opened. Thereby, carbon dioxide is adsorbed and removed by supplying the off gas C stored in the off gas tank 14 from the off gas supply line 301 to the first off gas adsorption tower 15a, and the CO ₂ removal off gas D is a CO ₂ removal off gas discharge line It is supplied into the buffer tank 16 for CO ₂ removal off gas from 302 and temporarily stored in the buffer tank 16 for CO ₂ removal off gas. On the other hand, the second off-gas adsorption tower 15b is regenerated under reduced pressure by using the suction pump 12 which is stopped and not operating in the hydrogen PSA apparatus main body. This regeneration step, the off-gas supply valve V12b and CO ₂ removal off-gas exhaust valve V13b is closed, by operating the suction pump 12 of the hydrogen PSA body, carbon dioxide adsorbed in the second offgas adsorption tower 15b is removed Separated, the adsorption tower is regenerated. At this time, the gas sucked from the inside of the second off-gas adsorption tower 15b by the suction pump 12 is discharged as the exhaust gas F from the air release line 102 by opening the air release valve V7. Carbon dioxide can proceed with desorption only in the pressure reduction step, and the pressure in the adsorption tower for off gas during regeneration of the adsorbent for off gas is preferably as low as possible. Thus, by utilizing the suction pump 12, the idle time of the suction pump 12 can be eliminated and the utilization efficiency of the suction pump 12 can be improved.

(From step 3 and step 4)
At the time when the regeneration process of the hydrogen PSA unit starts, the second off-gas adsorption tower 15b is switched from the regeneration process to the adsorption process. The exhaust gas discharge valve V14b is closed, the off gas supply valve V12b and the CO ₂ removal off gas discharge valve V13b are opened, and the off gas is supplied to the second off gas adsorption tower 15b to switch to the adsorption step. On the other hand, the first off-gas adsorption tower 15a that has completed the adsorption step is brought into the holding state by closing the off-gas supply valve V12a and the CO ₂ removal off-gas discharge valve V13a. After completion of the operation of the suction pump 12 of the hydrogen PSA apparatus main body, the same valve operation as in steps 1 and 2 is performed to regenerate the first off-gas adsorption tower 15a. The subsequent steps are repeated while replacing the adsorption towers performing the adsorption removal step and the regeneration step. By such an adsorption removal method, it becomes possible to perform adsorption and regeneration simultaneously in different adsorption towers, and CO ₂ removal off gas D can be produced continuously.

  Since the off-gas C discharged from the hydrogen PSA unit 2 is temporarily stored in the off-gas tank 14, the temperature of the off-gas C supplied from the off-gas tank 14 is close to the ambient temperature around the off-gas tank 14 when the storage time is long. It becomes. When the outside air temperature is normal temperature, the adsorption capacity of carbon dioxide of the carbon dioxide adsorbent is secured even if the offgas C in the offgas tank 14 is supplied to the offgas adsorption towers 15a and 15b without temperature control.

  As a lower limit of the pressure of offgas C in adsorption towers 15a and 15b for offgases in a carbon dioxide removal process, 0.05 MPa is preferred and 0.08 MPa is more preferred. If the pressure of the off gas C in the off gas adsorption towers 15a and 15b is less than the above lower limit, the adsorption efficiency may be reduced, and the amount of adsorbent may be increased. On the other hand, if the pressure of the offgas C in the offgas adsorption towers 15a and 15b is too high, a compressor or the like for pressurizing the offgas C is required, and the equipment cost is increased. In addition, as the temperature of the off gas C at the time of adsorption is lower, the adsorption capacity of the adsorbent is increased. Therefore, it is preferable to carry out the carbon dioxide removal step at normal temperature and pressure.

In each of the offgas adsorption towers 15a and 15b, as described above, the carbon dioxide removal step and the adsorbent regeneration step are alternately repeated. The lower limit of the flow rate of the off gas C supplied in one carbon dioxide removal step is preferably 0.8, where the discharge amount of the off gas C discharged in one adsorption removal step of the hydrogen PSA device 2 is 1. , 0.9 is more preferred. On the other hand, the upper limit of the flow rate of the off gas C is preferably 1.2, more preferably 1.1, when the discharge amount of the off gas C discharged in one adsorption removal step of the hydrogen PSA device 2 is 1. . When the flow rate of the off gas C is less than the lower limit, the amount of CO ₂ removal off gas discharged decreases, and there is a possibility that the production efficiency of the product gas relative to the supply amount of the source gas may not be sufficiently improved. Conversely, when the flow rate of the off gas C exceeds the upper limit, the size of the off gas PSA device 3 may be increased, and operation control may be difficult. By making the flow rate of the off gas C supplied in one carbon dioxide removal step equal to the discharge amount of the off gas C discharged in one adsorption removal step of the hydrogen PSA device 2, the raw gas can be A remarkable improvement effect of the production efficiency of the product gas on the supply amount can be obtained.

(CO ₂ removal off gas utilization process)
The CO ₂ removal offgas utilization process, as the heat source of the reformer 1, and supplies the CO ₂ removal offgas D which were stored in CO ₂ removing offgas buffer tank 16 from the off-gas utilization line 303 to the reformer 1. Specifically, for example, a CO ₂ removal off gas D is supplied as a fuel for the combustion of the reformer burner 4. Since the CO ₂ removal off gas D has a high combustion efficiency due to the removal of carbon dioxide, it can be suitably used as an application to be directly burned like a fuel for the combustion of the reformer burner 4.

<Advantage>
According to the hydrogen gas production method, since the off gas D from which carbon dioxide is removed in the carbon dioxide removal step is used as a heat source of the reformer 1, the supply amount of the source gas A used as a heat source of the reformer 1 can be reduced. The production efficiency of the product gas E with respect to the supply amount of the source gas A can be improved. In the hydrogen gas production method, the offgas adsorption towers 15a and 15b used in the carbon dioxide removal step are filled with an offgas adsorbent that selectively adsorbs carbon dioxide. Thereby, carbon dioxide which is an inert gas can be efficiently removed from the off gas C discharged from the hydrogen PSA device 2, and the combustion efficiency of the off gas used as a heat source of the reformer 1 can be improved.

<Other Embodiments>
The hydrogen gas production method and the hydrogen production apparatus of the present invention are not limited to the above embodiments. For example, in the above embodiment, the CO ₂ removal off gas buffer tank 16 for temporarily storing the CO ₂ removal off gas is provided, but the CO ₂ removal off gas buffer tank 16 is not an essential component, and the off gas adsorption tower The discharged CO ₂ removal off gas may be supplied directly to the reformer. Even in this case, in the carbon dioxide removal step, the supply amount and the supply pressure of the CO ₂ removal off gas can be controlled by adjusting the pressure and the flow rate of the off gas to be supplied from the off gas tank to the off gas adsorption tower.

  Further, although the above embodiment has described the one provided with a reformer by steam reforming and auto thermal reforming, a hydrogen gas production method and a hydrogen gas production apparatus using a reformer by partial oxidation reforming are also disclosed. Within the intended scope of

In the above embodiment, the configuration in which the off-gas PSA apparatus includes two off-gas adsorption towers has been described, but the off-gas PSA apparatus may include one or more off-gas adsorption towers. If offgas adsorption tower offgas PSA apparatus provided in only one, it is not possible to supply the CO ₂ removal offgas to continuously removing CO ₂ off-gas buffer tank, for example, storage capacity of the CO ₂ removing offgas buffer tank The CO ₂ removal off gas can be continuously supplied to the reformer by increasing In addition, when the off-gas PSA apparatus includes three or more off-gas adsorption towers, the supply amount of raw material gas and the like used as a heat source of the reformer can be further reduced, and the hydrogen recovery rate can be further improved.

  In the above embodiment, although the suction pump of the hydrogen PSA device is used for depressurization of the off gas adsorption tower, the off gas suction pump may be provided in the off gas PSA device separately from the suction pump of the hydrogen PSA device. By providing the off-gas PSA apparatus with the off-gas suction pump, the off-gas PSA apparatus can operate independently of the operation of the hydrogen PSA apparatus, and it becomes easy to control the carbon dioxide removal operation.

  In the above embodiment, the hydrogen gas production method by steam reforming of hydrocarbon-containing gas has been described, but a hydrogen gas production method using partial oxidation reforming or autothermal reforming of hydrocarbon-containing gas is also described in the present invention. It is within the intended range. When partial oxidation reforming or autothermal reforming is used, off gas can be supplied to the reformer as source gas. At this time, the off gas may be pressurized and supplied using a compressor. When auto thermal reforming is used, the off gas can be used as a fuel for generating steam supplied to the reformer in the off gas utilization step.

  EXAMPLES The present invention will be more specifically described below with reference to examples, but the present invention is not limited to these.

Example 1
The hydrogen producing apparatus shown in FIG. 1 provided with the off gas PSA apparatus 3 for removing CO ₂ in the off gas is referred to as Example 1.

Comparative Example 1
As a conventional configuration, the hydrogen production apparatus of FIG. 4 which is used as a heat source of the reformer 1 without removing CO ₂ in the off gas is set as Comparative Example 1.

<Calculation of combustion efficiency>
About the said Example 1 and Comparative Example 1, each combustion efficiency was compared by simulation.

If off gas C or CO ₂ removing off gas D and source gas A are used as fuel for the reformer burner 4, the source gas A supplied as fuel for the reformer burner 4 when the combustion efficiency of the off gas is improved. Supply is reduced. Therefore, as the combustion efficiency, the amount of the raw material gas A necessary as the fuel for the reformer burner 4 was calculated using a steady process simulator (“PRO / II ver 9.1” by invensys).

  As simulation conditions, natural gas (methane gas) is used as the raw material gas A, the reforming temperature of the reformer 1 is 800 ° C., the shift reaction temperature is 250 ° C., and the hydrogen recovery rate of the adsorption towers 11a, 11b, 11c of the hydrogen PSA device 2 is 80 %, The carbon dioxide recovery rate of the offgas adsorption towers 15a and 15b of the offgas PSA apparatus 3 is 80%, and the combustion temperature of the reformer burner 4 is 1100.degree. The amount of natural gas supplied to obtain 1 kmol / h of product gas E as fuel for the reformer burner 4 was calculated.

  As a result of the above simulation, the supply amount of natural gas necessary as a fuel for the reformer burner 4 to obtain 1 kmol / h of product gas E is 0.0275 kmol / h in Example 1 and 0.0305 kmol / h in Comparative Example 1. It was h.

  From these results, it was found that Example 1 can reduce the supply amount of natural gas necessary as fuel for the reformer burner 4 by 9.84%, as compared with Comparative Example 1. Therefore, it can be said that the combustion efficiency of off gas can be greatly improved by providing the off gas PSA device 3 as compared with the conventional hydrogen production device.

  As described above, the hydrogen gas production method and the hydrogen production apparatus can improve the combustion efficiency of the off gas used as a heat source of the reformer and reduce the supply amount of the raw material gas and the like to the product gas, so high purity It is suitably used as a hydrogen production apparatus or the like for producing hydrogen.

1, 1a Reformer 2 Hydrogen PSA unit 3 Offgas PSA unit 4 Reformer burner 11a, 11b, 11c Adsorption tower 12 Suction pump 13 Buffer tank for product gas 14 Offgas tank 15a, 15b Adsorption tower for offgas 16 CO ₂ removal offgas For buffer tank 101 reformed gas supply line 102 atmosphere open line 103 adsorption tower pressure reduction line 104 off gas discharge line 105 connection line 201 product gas discharge line 202 pressure equalizing line 203 cleaning line 301 off gas supply line 302 CO ₂ removal off gas discharge line 303 off gas Utilization line 304 Off-gas adsorption tower pressure reduction line V1a, V1b, V1c Reformed gas supply valve V2a, V2b, V2c Product gas discharge valve V3a, V3b, V3c Offgas discharge valve V4a, V4b, V4c average Valves V5a, V5b, V5c flush valve V6 buffer tank connected valve V7 atmosphere opening valve V8 suction pump connection valve V9 pressure reducing valve V10 off gas tank feed valve V11 off gas tank discharge valve V12a, V12B offgas supply valve V13a, V13b CO ₂ removal off gas discharge Valve V14a, V14b Exhaust gas exhaust valve A Source gas B Reformed gas C Off gas D CO ₂ removal off gas E Product gas F Exhaust gas G Air H Water I Steam J Oxygen

Claims (15)

Produces high-purity hydrogen gas using a reformer that generates a hydrogen-rich reformed gas by autothermal reforming of a hydrocarbon-containing gas and a hydrogen PSA unit that removes gases other than hydrogen in this reformed gas Hydrogen gas production method,
Removing carbon dioxide from the off-gas discharged from the hydrogen PSA unit using an off-gas adsorption tower;
Using the off gas from which carbon dioxide has been removed in the carbon dioxide removal step as a heat source or a source gas ,
A hydrogen gas production method characterized in that the off gas is used as a fuel for generating steam supplied to the reformer in the off gas utilization step . Using a reformer that generates a hydrogen-rich reformed gas by partial oxidation reforming or autothermal reforming of a hydrocarbon-containing gas, and a hydrogen PSA device that removes gases other than hydrogen in the reformed gas A hydrogen gas production method for producing purity hydrogen gas, comprising:
Removing carbon dioxide from the off-gas discharged from the hydrogen PSA unit using an off-gas adsorption tower;
Using the off gas from which carbon dioxide has been removed in the carbon dioxide removal step as a heat source or a source gas,
In the above-mentioned off gas utilization step, the off gas is supplied as a source gas to the reformer, and a hydrogen gas production method. The method for producing hydrogen gas according to claim 1 or 2 , wherein the offgas adsorption tower is filled with activated carbon as an offgas adsorbent for selectively adsorbing carbon dioxide. The method for producing hydrogen gas according to claim 3 , wherein the adsorption tower for off gas is further filled with a moisture removing adsorbent. The method for producing hydrogen gas according to any one of claims 1 to 4 , wherein the hydrogen PSA device has an adsorption tower packed with an adsorbent which selectively adsorbs carbon monoxide. A material in which the above-mentioned adsorbent which selectively adsorbs carbon monoxide supports copper (I) halide or copper (II) halide supported on at least one of porous silica, porous alumina and polystyrene. 6. The method for producing hydrogen gas according to claim 5 , wherein a material obtained by reducing the material or a material obtained by ion exchange of cations in zeolite to monovalent copper (Cu (I)) is used as a main component. The hydrogen gas production method according to any one of claims 1 to 6 , wherein the hydrogen PSA device is a vacuum regeneration type hydrogen PSA device which performs a pressure reduction operation below normal pressure when the adsorbent is regenerated. The method for producing hydrogen gas according to claim 7 , wherein the hydrogen PSA device has a suction pump for reducing the pressure of the adsorption column of the hydrogen PSA device to atmospheric pressure or lower. The method for producing hydrogen gas according to claim 8 , further comprising the step of regenerating the adsorbent for off gas by pressure reduction of the adsorption tower for off gas by a suction pump of the hydrogen PSA device. 10. The hydrogen gas production method according to claim 9 , wherein the offgas adsorbent regeneration step is performed when the suction pump is not operating in the hydrogen PSA device. The method according to claim 9 or 10 , wherein a plurality of the offgas adsorption towers are used and the one carbon dioxide removal process is performed in the one offgas adsorption tower while the adsorbent regeneration process is performed in the other offgas adsorption towers. Hydrogen gas production method. The hydrogen gas production method according to any one of claims 1 to 11 , wherein in the carbon dioxide removing step, carbon dioxide of the off gas is removed under normal temperature and normal pressure. The hydrogen gas production method according to any one of claims 1 to 12 , further comprising the step of temporarily storing the off gas from which carbon dioxide has been removed in the carbon dioxide removal step. A hydrogen gas producing apparatus comprising: a reformer for producing a hydrogen-rich reformed gas by autothermal reforming of a hydrocarbon-containing gas; and a hydrogen PSA device for removing a gas other than hydrogen in the reformed gas ,
An offgas adsorption tower for removing carbon dioxide from the offgas discharged from a hydrogen PSA unit;
And an off gas utilization line that uses the off gas from which carbon dioxide has been removed by the off gas adsorption tower as a heat source or a source gas ,
A hydrogen gas producing apparatus characterized in that the offgas from which the carbon dioxide is removed is used as a fuel for producing steam supplied to the reformer . Hydrogen gas provided with a reformer that generates a hydrogen-rich reformed gas by partial oxidation reforming or autothermal reforming of a hydrocarbon-containing gas, and a hydrogen PSA device that removes gases other than hydrogen in the reformed gas A manufacturing device,
An offgas adsorption tower for removing carbon dioxide from the offgas discharged from a hydrogen PSA unit;
And an off gas utilization line that uses the off gas from which carbon dioxide has been removed by the off gas adsorption tower as a heat source or a source gas,
A hydrogen gas production apparatus characterized in that the off gas from which the carbon dioxide is removed is supplied as a source gas to the reformer.

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