JP2006342014A - Method for producing high purity hydrogen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing high purity hydrogen, by which high purity hydrogen can obtained at a high efficiency while realizing the reduction of cost by compacting a production apparatus. <P>SOLUTION: High purity hydrogen D is obtained by forming a hydrogen-enriched converted gas B by reforming and converting a hydrocarbon-containing fuel A with steam in a reforming converter 1, then adsorbing and removing CO by bringing the converted gas G into contact with a copper halide-supporting CO adsorbing agent filled in a CO remover 2, storing hydrogen in a hydrogen storing material in a hydrogen separation/recover unit 3, and discharging the stored hydrogen from the hydrogen storing material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing high-purity hydrogen used in proton-conducting fuel cells such as phosphoric acid type and solid polymer type, and more specifically, in the production of hydrogen which is energy (fuel) of a fuel cell. The present invention relates to a method for efficiently producing high-purity hydrogen by removing produced carbon monoxide, carbon dioxide, water, unreacted methane, and the like.

In recent years, there is an increasing expectation for hydrogen as a fuel for fuel cells that leads to improvement of the global environment. In general, hydrogen is obtained by reforming and reforming a hydrocarbon-containing fuel such as natural gas, naphtha, kerosene, or methanol and steam in the presence of a metal catalyst. The modified gas (metamorphic gas) contains carbon monoxide (CO), carbon dioxide (CO ₂ ), methane (CH ₄ ), water (H ₂ O), etc. in addition to hydrogen. In order to reduce the voltage output by adsorbing to the electrode of a low temperature fuel cell such as a polymer electrolyte fuel cell, it is necessary to remove it to the ppm level.

A typical method for obtaining high purity hydrogen is a hydrogen PSA method. The hydrogen PSA method is a method of separating by utilizing the difference in adsorption / desorption behavior of each gas component to the adsorbent, and adsorbs impurities such as CO, CO ₂ , CH ₄ , H ₂ O under high pressure. This is a method for recovering only H ₂ having a lower adsorption affinity than the above gas. The adsorbed impurity gas component is desorbed by reduced pressure and released out of the system. The hydrogen PSA apparatus according to this method is composed of a plurality of adsorption towers. In each adsorption tower, an operation combining the adsorption process, the pressure equalization process, the pressure reduction process, the purge process and the pressure increase process is repeated. (See, for example, Non-Patent Document 1). The adsorption tower is filled with activated carbon, zeolite and activated alumina as adsorbents alone or in layers, and can produce 99.999% by volume or more of high-purity hydrogen. However, in order to remove CO to the ppm level with these adsorbents, a large amount of adsorbent is required, which causes the problem that the adsorption tower becomes large and the yield of H ₂ decreases.

Further, for the purpose of producing a hydrogen-rich fuel gas suitable for a fuel cell, a method for removing CO by passing the reformed / modified gas through a copper halide adsorbent is disclosed (Patent Literature). 1). However, although this method can remove CO, but cannot remove other gases such as CO ₂ , there is a problem that power generation efficiency decreases when fuel gas is supplied to the fuel cell. In addition, when fuel gas is supplied for a long period of time, there remains a problem that the influence of gases other than H ₂ and CO on the electrodes of the fuel cell is unknown at this time.

Further, a method of removing CO ₂ , CH ₄ , and H ₂ O using hydrogen PSA after removing CO with a CO selective oxidation catalyst has been studied (see Non-Patent Document 2). This method removes CO, which is the main cause of the increase in the size of the adsorption tower in the hydrogen PSA method, leading to downsizing of the adsorption tower. However, when introducing air to oxidize CO, CO oxidation, etc. since it is necessary to supply oxygen or the amount of oxygen which does not react with the CO together reduces the recovery efficiency of H ₂ consumed and H ₂ react with H _2, methanation occurs as a side reaction, PSA There is a problem that CH _{4 that} is difficult to remove by N2 is generated and nitrogen (N ₂ ) that is also difficult to remove by PSA is mixed in the system.

As a method for producing high-purity hydrogen as fuel for fuel cells, after removing CO with a CO adsorbent from the gas generated in a gasification furnace by the PSA method, occlusion / release of H ₂ by a hydrogen storage alloy A method for obtaining high-purity hydrogen by combining operations is disclosed (see Patent Document 2). In this method, the purification process of crude hydrogen after removing CO is performed using a hydrogen storage alloy, so that the purification process of crude hydrogen can be greatly reduced in size. However, since the removal of CO is performed using conventional adsorbents such as zeolite molecular sieves, carbon molecular sieves, activated carbon, or activated alumina, as described above, a large amount of adsorbent is required to remove CO to the ppm level. Therefore, the problem of increasing the size of the adsorption tower has not been solved.
Supervised by Atsushi Takeuchi, "Handbook of latest adsorption technology", NTS Corporation, January 1999, p. 86 NEDO 2001 Report, Development of Hydrogen Production Technology by New PSA Method, 2002 JP 2002-201005 (Claims etc.) WO00 / 59825 pamphlet (claims, etc.)

  Accordingly, an object of the present invention is to provide a method for producing high-purity hydrogen that can obtain high-purity hydrogen with high efficiency while realizing cost reduction by downsizing the production apparatus.

  The invention described in claim 1 is a CO adsorption / removal step in which a CO-containing hydrogen rich gas is brought into contact with a CO adsorbent to adsorb and remove CO to obtain a CO removed gas, and hydrogen contained in the CO removed gas is stored in hydrogen. A high-purity hydrogen production method comprising: a hydrogen separation step having a hydrogen occlusion step in which a material is occluded and a hydrogen release step in which the occluded hydrogen is released from the occlusion material, wherein the CO adsorbent is A material in which copper (I) halide and / or copper (II) halide is supported on one or more supports selected from the group consisting of silica, alumina, activated carbon, graphite, and polystyrene resin. This is a high-purity hydrogen production method characterized.

  According to a second aspect of the present invention, there is provided a hydrogen separation process comprising: a hydrogen storage step for storing hydrogen contained in a hydrogen rich gas containing CO into a hydrogen storage material; and a hydrogen release step for releasing the stored hydrogen from the storage material. A high-purity hydrogen production method comprising: a recovery step; and a CO adsorption / removal step of adsorbing and removing CO by bringing the released hydrogen into contact with a CO adsorbent, wherein the CO adsorbent is silica, alumina And a material obtained by supporting copper (I) halide and / or copper (II) halide on at least one carrier selected from the group consisting of activated carbon, graphite and polystyrene resin. This is a high-purity hydrogen production method.

The invention according to claim 3 is the method for producing high-purity hydrogen according to claim 1 or 2, wherein the hydrogen-rich gas containing CO is any one of the following gases (a) to (e).
(A) Gas obtained by reforming hydrocarbon-containing fuel with steam (b) Gas obtained by reforming hydrocarbon-containing fuel by partial oxidation (c) Hydrocarbon-containing fuel is reformed by partial oxidation and simultaneously reformed with steam Gas (d) Gas obtained by further modifying the gas (a), (b) or (c) (e) The gas (a), (b) or (c) is further converted into a crude separation membrane such as a ceramic filter. Gas with increased hydrogen concentration

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the CO adsorption removing step includes a CO adsorption step for adsorbing and removing CO and a CO adsorbent regeneration step for regenerating the CO adsorbent. The high-purity hydrogen production method described in the item.

  Invention of Claim 5 performs the said CO adsorption removal process using the CO removal device provided with two or more CO adsorption towers filled with the said CO adsorbent, About one CO adsorption tower, 5. The high-purity hydrogen production method according to claim 4, wherein the CO adsorption step and the CO adsorbent regeneration step are alternately performed, and the CO adsorption step is performed in at least one CO adsorption tower at an arbitrary time point. It is.

In the invention according to claim 6, the CO adsorption removal step is performed using a CO remover including three or more CO adsorption towers filled with the CO adsorbent. The following (1) and ( 6. The high purity hydrogen production method according to claim 5, wherein the step 2) is repeated.
(1) A step of performing the CO adsorption step by connecting the remaining CO adsorption towers in series while performing the CO adsorbent regeneration step in any one of the CO adsorption towers. (2) Next, connecting in series A step of separating the most upstream CO adsorption tower from the series connection among the CO adsorption towers, and connecting the CO adsorption tower having completed the CO adsorbent regeneration step to the most downstream side of the series connection.

  The invention according to claim 7 uses any one of two or more of hydrogen storage alloy, surface-treated hydrogen storage alloy, chemical hydride, carbon nanotube, or any of these as the hydrogen storage material. 2. The high-purity hydrogen production method according to item 1.

  According to an eighth aspect of the present invention, in the CO adsorption and removal step, the reaction temperature is 80 ° C. or lower and the atmospheric pressure is normal pressure or higher when CO is adsorbed and removed by the CO adsorbent. The high-purity hydrogen production method according to any one of the above items.

  The invention according to claim 9 is the high-purity hydrogen production method according to any one of claims 1 to 8, wherein the reaction temperature in the hydrogen storage step is 80 ° C. or lower and the atmospheric pressure is normal pressure or higher. .

  In the CO adsorbent regeneration step, the invention according to claim 10 is such that a gas substantially free of CO is circulated in the CO adsorbent regeneration step, the reaction temperature is equal to or higher than the reaction temperature in the CO adsorption step and 250 ° C. It is a high purity hydrogen manufacturing method of any one of Claims 4-9 made into the atmospheric pressure or less in a CO adsorption step.

  The invention according to claim 11 is a gas that does not substantially contain CO, an off-gas that is not occluded in the hydrogen occlusion step, high-purity hydrogen that is released in the hydrogen desorption step, and heating for the step of performing the reforming. The method for producing high-purity hydrogen according to claim 10, wherein fuel or a mixed gas of any two or more of these is used.

  The invention according to claim 12 is the high purity according to any one of claims 1 to 11, wherein the reaction temperature in the hydrogen releasing step is 250 ° C. or lower and the atmospheric pressure is lower than or equal to the atmospheric pressure in the hydrogen storage step. This is a hydrogen production method.

  According to a thirteenth aspect of the present invention, the heat generated when the hydrogen storage material stores hydrogen in the hydrogen storage step is used to raise the temperature of the CO adsorbent in the CO adsorbent regeneration step. The high-purity hydrogen production method according to any one of 12 above.

  The invention described in claim 14 is any one of claims 1 to 13, wherein heat generated when the hydrogen storage material stores hydrogen in the hydrogen storage step is used to raise the temperature of the hydrogen storage alloy. The high-purity hydrogen production method described.

  According to a fifteenth aspect of the present invention, the heat generated when the CO adsorbent adsorbs CO in the CO adsorption removal step is used for raising the temperature of the hydrogen storage material in the hydrogen release step. The high-purity hydrogen production method according to any one of the above.

  In order to obtain the reaction temperature in the CO adsorption step, the invention according to claim 16 includes the latent heat of water vapor contained in the hydrogen-rich gas containing CO, the sensible heat of the hydrogen-rich gas, and the step of performing the reforming. The process gas and / or the CO adsorbent is heated by using latent heat of water vapor contained in the combustion exhaust gas, sensible heat of the combustion exhaust gas, or any two or more thereof. The high-purity hydrogen production method described.

  In order to obtain the reaction temperature in the hydrogen releasing step, the invention according to claim 17 is characterized in that in order to obtain the reaction temperature in the hydrogen releasing step, the latent heat of water vapor contained in the hydrogen rich gas containing CO, the hydrogen rich gas 17. The hydrogen storage material according to claim 12, wherein the hydrogen storage material is heated using sensible heat of sensible heat of the combustion exhaust gas from the step of performing the reforming, or any two or more thereof. This is a high-purity hydrogen production method.

  According to the present invention, high purity hydrogen can be obtained with high efficiency by combining a CO adsorbent carrying a copper halide with excellent adsorption performance and a hydrogen storage material. As a result, the manufacturing apparatus can be greatly downsized, and high-purity hydrogen can be obtained at low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the flowcharts of FIGS. In the following embodiments, as a hydrogen-rich gas containing CO (hereinafter, also simply referred to as “hydrogen-rich gas”), a gas obtained by reforming a hydrocarbon-containing fuel after reforming with steam (hereinafter referred to as “modified gas”). Will be explained as a representative example.

Embodiment 1
An example of the embodiment is shown in the flowchart of FIG. In the present embodiment, an example is shown in which the switching operation between the adsorption / regeneration of the CO adsorbent and the hydrogen occlusion / hydrogen release of the hydrogen occlusion material is performed by raising and lowering the reaction temperature (that is, temperature swing).

(Reformation / transformation process)
In the reforming / transformation process for producing the shift gas as the hydrogen-rich gas containing CO, for example, a combination of a steam reformer and a shifter that are usually used (generically referred to as “reformer / transformer 1”). ) May be used. In the reformer, the hydrocarbon-containing fuel A such as natural gas is reformed with steam to form a reformed gas mainly composed of H ₂ and CO, and then steam is further added to the reformed gas in the transformer. Alteration is performed to generate a (hydrogen-rich) modified gas B containing H ₂ as a main component. In this metamorphic gas B, in addition to H ₂ , together with CO ₂ , a small amount of CH ₄ , H ₂ O, etc., about 0.5 volume% (hereinafter simply referred to as “%”) CO remains. ing.

(CO adsorption removal process)
In the CO adsorption removal step of the present invention, a CO remover 2 comprising three CO adsorption towers (2a, 2b, 2c) filled with a CO adsorbent is used. Hereinafter, the CO adsorption removal step and the CO adsorbent regeneration step will be described separately, and the switching operation of those steps will be described.

    [CO adsorption removal step]: The modified gas B is passed through the CO remover 2 filled with the CO adsorbent, and CO in the modified gas B is selectively removed. As the CO adsorbent, a material in which copper (I) halide or copper (II) halide is supported on one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite, and polystyrene resin. Use. Such a CO adsorbent carrying copper halide exhibits adsorption performance several times that of conventional adsorbents such as zeolite molecular sieves, carbon molecular sieves, activated carbon, or activated alumina. The size can be greatly reduced. Since the CO adsorption reaction by the CO adsorbent is promoted as the temperature is lower, a heat exchanger 4 is provided on the upstream side of the CO remover 2 in order to cool the high temperature modified gas B, and the modified gas B ′ after cooling is provided. It is preferable to lower the temperature to 80 ° C. or lower, and further to 60 ° C. or lower, and set the reaction temperature in this step within these temperature ranges. The CO concentration of the CO removal gas C after CO adsorption removal is preferably 100 ppm or less, more preferably 10 ppm or less, in order to suppress poisoning of the hydrogen storage material in the next step.

    [CO adsorbent regeneration step]: In order to maintain the adsorption performance of the CO adsorbent, the CO concentration on the outlet side of the CO remover 2 rises to a predetermined concentration after elapse of a predetermined time in the CO adsorption removal step. It is necessary to regenerate the CO adsorbent. The regeneration of the CO adsorbent requires desorption of CO adsorbed on the adsorption site and removal of the desorbed CO without re-adsorption, so that a gas substantially free of CO is circulated as a carrier gas. Do. In addition, since the CO desorption reaction is accelerated as the temperature increases, the reaction temperature in the CO adsorbent regeneration step is set higher than the reaction temperature in the CO adsorption removal step. In order to satisfy such conditions, as the gas that does not substantially contain CO used as the carrier gas, for example, a part E ′ of the off-gas E that has not been occluded by the hydrogen separation and recovery device described later is used. May be used after exchanging heat with the modified gas B in the heat exchanger 4 described above. However, when heated above 250 ° C., the active species carried on the adsorbent is irreversibly damaged, and the performance of the CO adsorbent is lowered. A particularly recommended temperature range is 80-150 ° C. The gas E ″ after the regeneration of the CO adsorbent contains CO at a high concentration, so that it may be effectively used instead of, for example, part of the heating fuel F for the reformer.

  [Switching operation between CO adsorption removal step and CO adsorbent regeneration step]: For each CO adsorption tower, it is necessary to alternately switch the CO adsorption removal step and the CO adsorbent regeneration step. In order to produce hydrogen (that is, in order to obtain CO removal gas C continuously), at least one of the three towers must always be in the CO adsorption removal step. In order to perform the regeneration sufficiently by shifting the CO adsorption tower in the CO adsorption removal step to the CO adsorbent regeneration step, it takes a long time to raise the temperature of the CO adsorbent to a temperature at which the CO desorption reaction is activated. Therefore, it is recommended that two of the three columns be used as the CO adsorption removal step, and only the remaining one column be the CO adsorbent regeneration step. Then, as shown in FIG. 2 (a), the two towers (2a, 2b) in the CO adsorption removal step are connected in series, and the modified gas B ′ is not distributed to the two towers, but passed through the two towers. It is made to pass through in order to adsorb and remove CO. When the CO adsorption capacity of the upstream CO adsorption tower 2a is almost full after a predetermined time has elapsed, the upstream CO adsorption tower 2a is disconnected from the series connection, and the adsorbent regeneration is completed. The tower 2c is connected to the downstream side of the CO adsorption tower 2b. Then, as shown in FIG. 5B, CO is adsorbed and removed using a series connection composed of the CO adsorption towers 2b and 2c while regenerating the adsorbent of the CO adsorption tower 2a. Thereafter, the same procedure is followed to return to the state shown in FIG. 5C and further to the state shown in FIG. 5A, and such a switching operation is repeated. In this way, by connecting two towers in series and performing regeneration sequentially from the upstream side, the downstream CO adsorption tower is always in a state of leaving the CO adsorption capacity, so breakthrough (CO concentration increase) Thus, the CO removal gas C from which CO has been sufficiently removed is always obtained. In addition, the upstream CO adsorption towers can be used up to the state where their adsorption capacity is almost used up, so there is no need to fill each adsorption tower with an excessive amount of adsorbent, reducing the adsorbent cost and downsizing the equipment. it can.

(Hydrogen separation and recovery process)
In the hydrogen separation / recovery process of the present invention, a hydrogen separation / recovery device 3 comprising two hydrogen storage material containers (3a, 3b) filled with a hydrogen storage material is used. Hereinafter, the hydrogen storage step and the hydrogen release step will be described separately, and the switching operation of these steps will be described.

[Hydrogen storage step]: The CO removal gas C is passed through the hydrogen separation and recovery device 3 filled with a hydrogen storage material, and H ₂ in the CO removal gas C is selectively stored. As the hydrogen storage material, a hydrogen storage alloy is suitable, and a material obtained by subjecting the hydrogen storage alloy to surface treatment is more preferable because poisoning by CO can be sufficiently suppressed. The surface treatment of the hydrogen storage alloy is not particularly limited as long as it has durability against CO ₂ , H ₂ O, and CO, and examples thereof include fluorination treatment. Since the hydrogen absorption reaction by the hydrogen storage material is promoted as the temperature is lower, the CO removal gas C discharged from the previous process is introduced by cooling it with a water-cooling jacket if necessary, and the reaction temperature in this step is 80 ° C. or less. Further, it is preferable to set the temperature to 60 ° C. or lower. Gases other than H ₂ (such as CO ₂ , CH ₄ , H ₂ O, etc.) that have not been absorbed by the hydrogen storage material may be washed off-gas E as needed and then discharged out of the system.

    [Hydrogen desorption step]: Since the reaction for desorbing hydrogen from the hydrogen occlusion material that occludes hydrogen is accelerated as the temperature increases, the reaction temperature in the hydrogen desorption step is the same as that in the hydrogen occlusion step. Above the reaction temperature. In order to satisfy such conditions, for example, the sensible heat of the combustion exhaust gas G of the reformer may be used to indirectly raise the temperature of the hydrogen storage material using the heat exchanger 5. In addition, when the temperature of the hydrogen storage material cannot be sufficiently raised only by the sensible heat of the combustion exhaust gas G of the reformer, the shortage is exhausted from the fuel cell (heat generated when the hydrogen storage material stores hydrogen) or Reforming fuel can also be used. However, if the temperature exceeds 250 ° C., the temperature difference from the time of occlusion increases, and the hydrogen occlusion material is pulverized by cycle thermal stress. Further, if the heating temperature is increased, the performance of the hydrogen storage material is lowered due to an increase in heat loss and the like. The particularly recommended temperature range is from room temperature to 200 ° C.

    [Switching operation between hydrogen storage step and hydrogen release step]: For each hydrogen storage material container, it is necessary to alternately switch between the hydrogen storage step and the hydrogen release step. In the example, 3a) is a hydrogen storage step, and the other hydrogen storage material container (3b in this example) is a hydrogen release step. As a result, high-purity hydrogen can be continuously supplied to a subsequent fuel cell or the like, so that a buffer tank for temporarily storing high-purity hydrogen as described later can be omitted or downsized.

[Embodiment 2]
Another embodiment is shown in FIG. In the first embodiment, the example in which the switching operation between the adsorption / regeneration of the CO adsorbent and the hydrogen storage / hydrogen release of the hydrogen storage material is performed by raising and lowering the reaction temperature (that is, temperature swing) is shown. An example in which these switching operations are performed by raising and lowering atmospheric pressure (that is, pressure swing) is shown. Note that description of parts common to the first embodiment is omitted, and only different parts are described in detail.

The CO adsorption reaction by the CO adsorbent increases the CO adsorption capacity as the CO partial pressure increases, and the hydrogen storage material increases the hydrogen storage amount as the H ₂ partial pressure increases. In this case, it is preferable to increase the atmospheric pressure from the normal pressure. Therefore, as shown in FIG. 3, a booster 6 is provided between the heat exchanger 4 and the CO remover 2, and the transformed gas B ′ is boosted to 0.9 MPa, for example, and passed through the CO remover 2 to remove CO. Then, the CO removal gas C may be introduced as it is into the hydrogen separation / recovery device 3 to occlude H ₂ . In order to cool the modified gas B to a temperature suitable for the hydrogen storage reaction, as shown in the figure, for example, the reformer heating fuel F may be used as the low temperature side gas of the heat exchanger 4. As a result, the heating fuel F is preheated, so that an effect of saving fuel can be obtained.

  On the other hand, since the regeneration reaction of the CO adsorbent easily proceeds by making the pressure lower than the atmospheric pressure at the time of CO adsorption, in the CO adsorbent regeneration step, as shown in FIG. For example, the off-gas E may be reduced to normal pressure and then introduced into the CO adsorption tower.

  In addition, since the hydrogen release reaction from the hydrogen storage material easily proceeds by lowering the atmospheric pressure at the time of the above hydrogen storage, in the hydrogen release step, as shown in FIG. For example, the pressure may be reduced to normal pressure using the pressure reducer 8.

[Embodiment 3]
FIG. 4 shows an example in which the order of the CO removal process and the hydrogen separation / recovery process in the first embodiment is switched. Note that description of parts common to the first embodiment is omitted, and only different parts are described in detail.

  As the hydrogen storage material, a hydrogen storage alloy or a surface-treated (for example, fluorinated) hydrogen storage alloy can be used as in the above examples, but in this embodiment, the modified gas B containing CO remains. Since 'is directly introduced into the hydrogen separation and recovery device 3, a hydrogen storage alloy having a surface treatment excellent in CO poisoning resistance (for example, fluorination treatment) is particularly suitable.

  In this embodiment, hydrogen in the modified gas B ′ is first selectively stored by the hydrogen storage material of the hydrogen separation and recovery device 3, and the remaining gas is discharged out of the system as off-gas E. At this time, a part of CO is adsorbed on the surface of the hydrogen storage material. Since CO adsorbed on the surface is desorbed when hydrogen is released from the hydrogen storage material, CO is contained in the hydrogen. High purity hydrogen D is obtained by introducing this CO-containing hydrogen H into the CO remover 2 and adsorbing and removing CO.

  Note that the CO adsorbed on the surface of the hydrogen storage material is a small part of the CO in the modified gas B ′, and therefore the CO remover of the CO remover 2 is not regenerated as frequently as in the first and second embodiments. Both can be used for a long time. Therefore, even if a plurality of CO adsorption towers are not provided as in the first and second embodiments, a single CO adsorption tower is used and the CO adsorbent is regenerated or replaced at the time of periodic inspection or the like. An effect can be obtained. In the present embodiment, an example is shown in which regeneration is performed by temperature swing using the reformer heating fuel F preheated by the heat exchanger 4.

(Modification)
In the first and second embodiments, an example in which three CO adsorption towers are sequentially switched as the CO adsorption removal step has been described. However, two or four or more CO adsorption towers may be sequentially switched and used. Even when the CO adsorption step is provided prior to the hydrogen separation and recovery step, as illustrated in Example 3, a single CO adsorption tower is used to regenerate or replace the adsorbent during periodic inspections. Also good. In contrast to the above, Embodiment 3 shows an example in which a single CO adsorption tower is used as the CO adsorption removal step. However, even when the CO adsorption step is provided after the hydrogen separation and recovery step, Similarly, a plurality of CO adsorption towers may be sequentially switched and used.

  Moreover, in the said Embodiment 1-3, although the example which uses two hydrogen storage material containers by switching alternately as a hydrogen separation-and-recovery process was shown, you may use three or more hydrogen storage material containers switching sequentially. . In addition, a single hydrogen storage material container and a buffer tank are combined, and high purity hydrogen is continuously supplied from the buffer tank to the subsequent fuel cell, etc., while hydrogen is stored by the hydrogen storage material in the single hydrogen storage material container. Hydrogen may be stored in the buffer tank only during the discharge while repeating the occlusion and the discharge.

  In the first to third embodiments, the hydrogen storage material and the surface-treated hydrogen storage alloy are exemplified as the hydrogen storage material. However, chemical hydride, carbon nanotube, or any two or more of these may be used.

  In the first and third embodiments, an example in which the switching operation of adsorption / regeneration of the CO adsorbent and hydrogen storage / hydrogen release of the hydrogen storage material is performed only by raising and lowering the reaction temperature (temperature swing) is shown. In the above, an example in which the switching is performed only by raising and lowering the atmospheric pressure (pressure swing) has been described, but both the temperature swing and the pressure swing may be appropriately combined.

  Further, in the first to third embodiments, the off-gas from the hydrogen separation / recovery device is exemplified as the gas that does not substantially contain CO used for the regeneration of the CO adsorbent. You may mix and use the fuel for a heater of a vessel, or any 2 or more types of these.

  In the first and second embodiments, the example in which the sensible heat of the modified gas is used as a heat source when the regeneration of the CO adsorbent and the release of hydrogen from the hydrogen storage material is performed by temperature swing has been described. You may use the latent heat of water vapor | steam, the sensible heat of the combustion exhaust gas of a reformer, or any 2 or more types of these.

  Alternatively, the heat generated in the hydrogen storage step may be used as a heat source for regeneration of the CO adsorbent, and the heat generated in the CO adsorption removal step may be used as a heat source for hydrogen release from the hydrogen storage material.

In the first to third embodiments, since unoccluded H ₂ may be contained in the off-gas from the hydrogen separation and recovery device, this off-gas can also be used as a heating fuel for the reformer.

  In the second embodiment, the example in which the pressure is reduced to the normal pressure using the pressure reducer when the CO adsorbent is regenerated and when the hydrogen is released from the hydrogen storage material has been shown. In order to further improve the efficiency, a vacuum pump or the like is used. It may be used to reduce the pressure to a negative pressure.

  In the first to third embodiments, an example in which the sensible heat of the combustion exhaust gas from the reformer is used as the heat source of the temperature swing is shown. However, the sensible heat of the reformer outlet gas, that is, the transformer inlet gas may be used. .

  In the first to third embodiments, the combination of the reformer and the transformer is illustrated as a means for producing the hydrogen-rich gas containing CO. However, a crude separation membrane such as a ceramic filter may be used instead of the transformer. . That is, in Embodiments 1 to 3 above, the gas (modified gas) modified after reforming the hydrocarbon-containing fuel with steam as the hydrogen-rich gas containing CO is exemplified. Naturally, a gas having a hydrogen concentration increased by circulating a crude separation membrane can also be applied.

  Furthermore, depending on the CO adsorption performance of the CO adsorbent and the CO poisoning resistance of the hydrogen storage material, a process using only the reformer can be realized by omitting the transformer. That is, as the hydrogen-rich gas containing CO, a gas that has been reformed with steam can also be applied. Further, instead of steam reforming, gas reformed by partial oxidation, or steam reformed simultaneously with partial oxidation. The gas modified with the above can also be applied.

  Further, CO released when the CO adsorbent is regenerated can be introduced into a shifter together with the reformed gas and used for the shift reaction.

1 is a flowchart showing a high-purity hydrogen production process according to Embodiment 1. FIG. FIG. 5 is a flowchart for explaining a CO remover switching operation in the first embodiment. FIG. 5 is a flowchart showing a high-purity hydrogen production process according to Embodiment 2. It is a flowchart which shows the high purity hydrogen manufacturing process which concerns on Embodiment 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reformer / transformer 2 ... CO remover 2a, 2b, 2c ... CO adsorption tower 3 ... Hydrogen separation and recovery device 3a, 3b ... Hydrogen storage material container 4, 5 ... Heat exchanger 6 ... Booster 7, 8 ... Pressure reducer A ... hydrocarbon-containing fuel B ... metamorphic gas (hydrogen rich gas containing CO)
C ... CO removal gas D ... High purity hydrogen E ... Off gas F ... Reformer heating fuel G ... Reformer combustion exhaust gas H ... CO-containing hydrogen

Claims (17)

A CO adsorption / removal step in which a hydrogen-rich gas containing CO is brought into contact with a CO adsorbent to adsorb and remove CO to obtain a CO removal gas; a hydrogen occlusion step in which hydrogen contained in the CO removal gas is occluded in a hydrogen occlusion material; and A hydrogen separation and recovery step having a hydrogen release step of releasing the stored hydrogen from the storage material, and a method for producing high-purity hydrogen comprising:
The CO adsorbent has copper (I) halide and / or copper (II) halide supported on one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite and polystyrene resin. A high-purity hydrogen production method characterized by being a material. A hydrogen separation and recovery process comprising a hydrogen storage step of storing hydrogen contained in a hydrogen-rich gas containing CO in a hydrogen storage material; and a hydrogen release step of releasing the stored hydrogen from the storage material; and the released hydrogen A method for producing high-purity hydrogen, comprising: a CO adsorption / removal step in which CO is adsorbed and removed by contacting with a CO adsorbent,
The CO adsorbent is made to carry copper (I) halide and / or copper (II) halide on one or more supports selected from the group consisting of silica, alumina, activated carbon, graphite and polystyrene resin. A method for producing high-purity hydrogen, characterized by comprising: The method for producing high-purity hydrogen according to claim 1 or 2, wherein the hydrogen-rich gas containing CO is any one of the following gases (a) to (e).
(A) Gas obtained by reforming hydrocarbon-containing fuel with steam (b) Gas obtained by reforming hydrocarbon-containing fuel by partial oxidation (c) Hydrocarbon-containing fuel is reformed by partial oxidation and simultaneously reformed with steam Gas (d) Gas obtained by further modifying the gas (a), (b) or (c) (e) The gas (a), (b) or (c) is further converted into a crude separation membrane such as a ceramic filter. Gas with increased hydrogen concentration   The high-purity hydrogen production method according to any one of claims 1 to 3, wherein the CO adsorption removal step includes a CO adsorption step for adsorbing and removing CO and a CO adsorbent regeneration step for regenerating the CO adsorbent. . The CO adsorption removal step is performed using a CO remover provided with a plurality of CO adsorption towers filled with the CO adsorbent,
For one CO adsorption tower, the CO adsorption step and the CO adsorbent regeneration step are alternately performed,
The high-purity hydrogen production method according to claim 4, wherein the CO adsorption step is performed in at least one of the CO adsorption towers at an arbitrary time. The CO adsorption / removal step is performed using a CO adsorption / removal device including three or more CO adsorption towers filled with the CO adsorbent, and the following steps (1) and (2) are repeated. The high-purity hydrogen production method according to claim 5.
(1) A step of performing the CO adsorption step by connecting the remaining CO adsorption towers in series while performing the CO adsorbent regeneration step in any one of the CO adsorption towers. (2) Next, connecting in series A step of separating the most upstream CO adsorption tower from the series connection among the CO adsorption towers, and connecting the CO adsorption tower having completed the CO adsorbent regeneration step to the most downstream side of the series connection.   The high-purity hydrogen production according to any one of claims 1 to 6, wherein a hydrogen storage alloy, a surface-treated hydrogen storage alloy, a chemical hydride, a carbon nanotube, or any two or more thereof is used as the hydrogen storage material. Method.   8. The high purity according to claim 1, wherein in the CO adsorption removal step, the reaction temperature is 80 ° C. or less and the atmospheric pressure is normal pressure or more when CO is adsorbed and removed by the CO adsorbent. Hydrogen production method.   The method for producing high-purity hydrogen according to any one of claims 1 to 8, wherein in the hydrogen storage step, the reaction temperature is 80 ° C or lower and the atmospheric pressure is normal pressure or higher.   In the CO adsorbent regeneration step, while allowing a gas substantially free of CO to flow, the reaction temperature is not lower than the reaction temperature in the CO adsorption step and not higher than 250 ° C., and the atmospheric pressure is not higher than the atmospheric pressure in the CO adsorption step. The high-purity hydrogen production method according to any one of claims 4 to 9.   As the gas that does not substantially contain CO, off-gas that is not stored in the hydrogen storage step, high-purity hydrogen that is released in the hydrogen release step, heating fuel for the reforming process, or any two of them The method for producing high-purity hydrogen according to claim 10, wherein a mixed gas of seeds or more is used.   The method for producing high-purity hydrogen according to any one of claims 1 to 11, wherein a reaction temperature in the hydrogen releasing step is 250 ° C or lower and an atmospheric pressure is an atmospheric pressure or lower in the hydrogen storage step.   The heat generated when the hydrogen storage material stores hydrogen in the hydrogen storage step is used for raising the temperature of the CO adsorbent in the CO adsorbent regeneration step. High purity hydrogen production method.   The method for producing high-purity hydrogen according to any one of claims 1 to 13, wherein heat generated when the hydrogen storage material stores hydrogen in the hydrogen storage step is used to raise the temperature of the hydrogen storage alloy.   The high heat according to any one of claims 1 to 14, wherein heat generated when the CO adsorbent adsorbs CO in the CO adsorption removal step is used for increasing the temperature of the hydrogen storage material in the hydrogen release step. Purity hydrogen production method.   In order to obtain the reaction temperature in the CO adsorption step, the latent heat of water vapor contained in the hydrogen-rich gas containing CO, the sensible heat of the hydrogen-rich gas, the latent heat of water vapor contained in the combustion exhaust gas from the reforming step, The method for producing high-purity hydrogen according to any one of claims 8 to 15, wherein the sensible heat of the combustion exhaust gas or any two or more of these is used to heat the processing gas and / or the CO adsorbent. In order to obtain the reaction temperature in the hydrogen releasing step, the latent heat of water vapor contained in the hydrogen-rich gas containing CO, the sensible heat of the hydrogen-rich gas, and the sensible heat of the combustion exhaust gas from the reforming process, or these The method for producing high-purity hydrogen according to any one of claims 12 to 16, wherein the hydrogen storage material is heated using any two or more of the above.

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