JP2017206421A - Method and apparatus for producing hydrogen gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing hydrogen gas capable of suppressing reduction in recovery ratio of hydrogen gas and shortening start-up time when repeating stopping and restarting of hydrogen gas purification.SOLUTION: There is provided a method for producing hydrogen gas which produces high purity hydrogen gas by purification with a plurality of adsorption towers from hydrogen-rich gas containing hydrogen gas and impurity gas other than hydrogen gas, which comprises a step of swinging residual gas between the plurality of adsorption towers by repeating a procedure for discharging residual gas in one adsorption tower of the plurality of adsorption towers from the inlet side of hydrogen rich gas to supply the residual gas from the inlet side of hydrogen rich gas to other adsorption towers while stopping the purification of hydrogen rich gas. Further, there is provided an apparatus for producing hydrogen gas which has a control mechanism for controlling to swing residual gas between the plurality of adsorption towers by repeating a procedure for discharging residual gas in one adsorption tower from the inlet side to supply the residual gas to other adsorption towers while stopping the purification of hydrogen rich gas.SELECTED DRAWING: Figure 2

Description

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

  In recent years, there is an increasing expectation for hydrogen as a fuel for fuel cells that leads to improvement of the global environment. As a typical hydrogen production method, impurities other than hydrogen contained in a hydrogen-rich gas obtained by reforming a hydrocarbon (natural gas) or dehydrogenating an organic hydride containing hydrogen are removed by a hydrogen purifier. There is a method (refer to JP 2014-73922 A). As this hydrogen purifier, there are adsorption towers using TSA (Temperature swing adsorption) method and PSA (Pressure swing adsorption) method.

  The above-described hydrogen production apparatus is generally operated so as to supply hydrogen to a hydrogen automobile during the day and stop the supply (purification) of hydrogen at night. Therefore, the purification of the hydrogen rich gas by the adsorption tower is stopped at night. The adsorption tower that has stopped the purification of the hydrogen-rich gas will finish the purification operation with an impurity gas other than hydrogen adsorbed on a part of the adsorbent, but the adsorbed impurity components are in an adsorption equilibrium state and are adsorbed. And the desorption are repeated, the impurity component diffuses to the unadsorbed adsorbent, and finally the adsorbent is adsorbed to all the adsorbent filled in the adsorption tower. Therefore, when refining is resumed after the purification of hydrogen-rich gas is stopped, the adsorbent on the adsorption tower outlet side is also in a state in which the impurity component is adsorbed. It needs to be processed. As a result, there are disadvantages that the recovery rate of hydrogen gas is reduced and it takes time to start up the supply of hydrogen gas.

JP 2014-73922 A

  The present invention has been made based on the above circumstances, and a hydrogen gas production method capable of suppressing a reduction in the recovery rate of hydrogen gas and shortening the startup time when repeatedly stopping and restarting hydrogen gas purification. And it aims at provision of a hydrogen gas production device.

  The present invention made to solve the above problems is a hydrogen gas production method for producing high-purity hydrogen gas by purification using a plurality of adsorption towers from hydrogen-rich gas containing hydrogen gas and impurity gas other than hydrogen, While the purification of the rich gas is stopped, the procedure of discharging the residual gas in one of the plurality of adsorption towers from the inlet side of the hydrogen rich gas and supplying the hydrogen gas into the other adsorption tower from the inlet side is repeated. The method further comprises the step of swinging the residual gas between the plurality of adsorption towers.

  According to the hydrogen gas production method, the adsorption breakthrough portion formed in the adsorbent of each adsorption tower is made to have a constant size by swinging the residual gas by taking in and out the hydrogen rich gas from the inlet side during the purification stop. Can keep. As a result, the diffusion of impurities during the purification stop is suppressed, and the contamination of the impurities into the purified gas discharged after the restart of the stop is suppressed. As a result, the hydrogen gas production method can suppress a decrease in the recovery rate of hydrogen gas and shorten the startup time until hydrogen gas supply. The term “swing” means that gas is circulated between a plurality of adsorption towers so that the gas is taken in and out of each adsorption tower.

  In the swing step, the hydrogen rich gas outlet sides of the adsorption tower for discharging the residual gas and the adsorption tower for supplying the residual gas may be circulated. By providing such a distribution line, the gas can be swung while suppressing the fluctuation of the internal pressure in the adsorption tower, and the movement of the adsorption breakthrough part to the adsorption tower outlet side can be minimized. it can.

  When the plurality of adsorption towers are PSA type, the pressure in the adsorption tower may be higher than that during purification in the swing process. As described above, in the PSA type adsorption tower, by increasing the pressure in the adsorption tower as compared with that during the purification, there is an effect that the diffusion rate of the gas component is lowered, and the diffusion of impurities can be more reliably suppressed. As a result, it is possible to promote the suppression of the decrease in the recovery rate of hydrogen gas and the shortening of the startup time until the supply of hydrogen gas.

  When the plurality of adsorption towers are TSA type, the temperature in the adsorption tower is preferably lower than that during purification in the swing step. Thus, in the TSA type adsorption tower, the diffusion rate of the gas component is reduced by lowering the temperature in the adsorption tower as compared with that during purification, and the diffusion of impurities can be more reliably suppressed. As a result, it is possible to promote the suppression of the decrease in the recovery rate of hydrogen gas and the shortening of the startup time until the supply of hydrogen gas.

  The hydrogen gas production method may further include a step of performing a dehydrogenation reaction of the organic hydride by heating in the presence of a catalyst, and the hydrogen rich gas may be a gas discharged in the dehydrogenation reaction step. As described above, by using the organic hydride for transport of the hydrogen-rich gas, the transport efficiency of hydrogen can be increased.

  Another invention made to solve the above-mentioned problems is a hydrogen gas production method for producing high-purity hydrogen gas by purification with an adsorption tower from hydrogen-rich gas containing hydrogen gas and impurity gas other than hydrogen, While the purification of the hydrogen rich gas is stopped, the procedure of discharging the residual gas in one of the plurality of adsorption towers from the hydrogen rich gas inlet side and supplying the remaining gas in the other adsorption tower from the hydrogen rich gas inlet side is repeated. Thus, a control mechanism for controlling the swing of the residual gas between the plurality of adsorption towers is provided.

  According to the hydrogen gas production device, the adsorption breakthrough portion formed in the adsorbent of each adsorption tower is made to have a constant size by swinging the residual gas by taking in and out the hydrogen rich gas from the inlet side during the purification stop. Can keep. As a result, the diffusion of impurities during the purification stop is suppressed, and the contamination of the impurities into the purified gas discharged after the restart of the stop is suppressed. As a result, the hydrogen gas production apparatus can suppress a decrease in the recovery rate of hydrogen gas and shorten the startup time until the supply of hydrogen gas.

  As described above, according to the hydrogen gas production method and the hydrogen gas production apparatus of the present invention, when the hydrogen gas purification is repeatedly stopped and restarted, it is possible to suppress a decrease in the recovery rate of hydrogen gas and shorten the startup time. .

It is the schematic which shows the hydrogen gas manufacturing apparatus of one Embodiment of this invention. It is a schematic diagram explaining the swing process of the hydrogen gas manufacturing method of one Embodiment of this invention.

  Hereinafter, embodiments of the hydrogen gas 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 gas production equipment]
The hydrogen gas production apparatus of FIG. 1 includes a reactor 1 that performs a dehydrogenation reaction of organic hydride A by heating in the presence of a catalyst, and an aromatic compound by cooling from a mixed gas of an aromatic compound and hydrogen discharged from the reactor 1. Separator 2 for gas-liquid separation of the compound, adsorption tower 3 for purifying the mixed gas (hydrogen rich gas B) separated by the separator 2, and product gas buffer for storing high purity hydrogen gas obtained by purification of hydrogen rich gas B A tank 4 is mainly provided. In addition, the hydrogen gas production apparatus discharges the residual gas in one adsorption tower 3 among the plurality of adsorption towers 3 from the inlet side of the hydrogen rich gas while stopping the purification of the hydrogen rich gas into the other adsorption tower 3. A control mechanism (not shown) is further provided for controlling the swinging of the residual gas between the plurality of adsorption towers 3 by repeating the procedure of supplying the hydrogen rich gas from the inlet side.

  Examples of the organic hydride A used in the hydrogen gas production apparatus include hydrogenated aromatic compounds such as methylcyclohexane (hereinafter also referred to as MCH), cyclohexane, dimethylcyclohexane, ethylcyclohexane, decalin, methyldecalin, dimethyldecalin, and ethyldecalin. It is done. For example, when MCH is used as the organic hydride A, it is converted to toluene which is an aromatic compound by a dehydrogenation reaction.

  The hydrogen gas production apparatus is used for supplying hydrogen to hydrogen-powered vehicles such as hydrogen automobiles and fuel cell automobiles, and for medium- and large-scale power generation using fuel cells.

<Reactor>
The reactor 1 is a dehydrogenation reactor that performs a dehydrogenation reaction of the organic hydride A by heating in the presence of a catalyst. Specifically, the reactor 1 has a dehydrogenation reaction catalyst that promotes the dehydrogenation reaction of the organic hydride A. The reactor 1 is heated from the organic hydride A and brought into contact with the dehydrogenation reaction catalyst to generate hydrogen from the organic hydride A. Causes an oxidation reaction to separate Thereby, a mixed gas of an aromatic compound and hydrogen is generated. In addition, when MCH is used as the organic hydride A, there is a possibility that unreacted MCH and by-products such as methane and benzene are included in the mixed gas.

  As the dehydrogenation reaction catalyst used in the reactor 1, for example, alumina carrying sulfur, selenium, fine particle platinum or the like is known.

  As a minimum of heating temperature of organic hydride A in reactor 1, 150 ° C is preferred and 200 ° C is more preferred. On the other hand, the upper limit of the heating temperature of the organic hydride A is preferably 400 ° C., more preferably 350 ° C. If the heating temperature of the organic hydride A is less than the lower limit, the reaction rate of the organic hydride A and the yield of hydrogen gas may be insufficient. Conversely, if the heating temperature of the organic hydride A exceeds the upper limit, the energy cost required for heating may be unnecessarily increased.

<Separator>
The separator 2 gas-liquid-separates the mixed gas of the aromatic compound and hydrogen discharged from the reactor 1 into a mixed gas of the aromatic compound and hydrogen by cooling to obtain a hydrogen rich gas B. The separator 2 has a cooling mechanism that cools the gas flowing inside. By cooling the gas inside the separator 2, it becomes easy to separate MCH, aromatic compounds, etc. having a relatively high boiling point from the mixed gas, and the concentration of aromatic compounds including toluene in the gas after separation is reduced. The The aromatic compound separated as a liquid is discharged from the separator 2 as drain D.

  As a minimum of the temperature of the mixed gas in the exit of the separator 2, -40 degreeC is preferable and -35 degreeC is more preferable. On the other hand, the upper limit of the temperature of the mixed gas at the outlet of the separator 2 is preferably −10 ° C., more preferably −15 ° C. If the temperature of the mixed gas at the outlet of the separator 2 is lower than the lower limit, the energy required for cooling the mixed gas may be excessive. Conversely, if the temperature of the mixed gas at the outlet of the separator 2 exceeds the above upper limit, the concentration of the aromatic compound in the mixed gas after separation is not sufficiently reduced, and the adsorption load in the subsequent adsorption tower increases. There exists a possibility that the lifetime of adsorbent may fall and the recovery rate of hydrogen gas may fall.

  The lower limit of the aromatic compound concentration in the mixed gas after separation by the separator 2 is preferably 50 ppm and more preferably 100 ppm. On the other hand, the upper limit of the aromatic compound concentration in the mixed gas is preferably 800 ppm and more preferably 600 ppm. If the aromatic compound concentration in the mixed gas is less than the lower limit, the cooling cost in the separator 2 may be significantly increased. On the other hand, if the concentration of the aromatic compound in the mixed gas exceeds the upper limit, the adsorption load in the subsequent adsorption tower increases, and the life of the adsorbent may be reduced or the hydrogen gas recovery rate may be reduced. is there. The “concentration” in this specification is a volume-based ratio.

<Adsorption tower>
The adsorption tower 3 purifies the mixed gas (hydrogen rich gas B) separated by the separator 2 and obtains high-purity hydrogen gas as the product gas E. Specifically, the adsorption tower 3 is filled with an adsorbent that can be regenerated by the TSA method or the PSA method, and in the hydrogen-rich gas B such as a hydrocarbon gas as a by-product generated in the dehydrogenation reaction from the organic hydride. To remove impurities contained in

  Specifically, the hydrogen gas production apparatus includes a plurality (two in the figure) of adsorption towers 3a and 3b. The number of adsorption towers 3 is arbitrary.

  The adsorption tower 3 is filled with an adsorbent that adsorbs the impurities in the hydrogen-rich gas B, and discharges a high-purity product gas E from the outlet side of the hydrogen-rich gas. The plurality of adsorption towers 3 are operated by sequentially switching a series of steps of adsorption, decompression, washing and pressure equalization, pressure increase, and adsorption. Specifically, after the adsorption step is completed, the adsorbed impurities are removed and the adsorbent is regenerated by reducing the pressure in the adsorption tower and cleaning (purging) with hydrogen gas, which is the product gas E. . Thereafter, the adsorption tower in which the adsorbent has been regenerated is pressurized again and subjected to hydrogen purification again. During operation of the hydrogen gas production apparatus, adsorption and regeneration are simultaneously performed in different adsorption towers by shifting the timing of the above series of steps in each adsorption tower so that at least one adsorption tower becomes an adsorption process. The product gas E can be produced continuously.

  The adsorption tower 3 is filled with an adsorbent capable of adsorbing MCH, toluene, methane, moisture, and the like, which are main impurities in the hydrogen rich gas B. The adsorbent is not particularly limited as long as it can adsorb impurities and can be regenerated by the TSA method or the PSA method. As such an adsorbent, X-type or A-type zeolite, activated carbon, porous silica, porous alumina, and a metal organic structure can be particularly preferably used.

  In addition, when removing multiple types of impurities, it is possible to respond by sequentially filling adsorbents adapted to each. Specifically, the aromatic compound adsorbent and the lower hydrocarbon adsorbent are preferably filled in order from the introduction side (inlet side) of the hydrogen rich gas B.

<Product gas buffer tank>
The product gas buffer tank 4 stores the product gas E, which is a high-purity hydrogen gas discharged from the adsorption tower 3, and supplies it to a hydrogen automobile or the like.

<Control mechanism>
The control mechanism included in the hydrogen gas production apparatus discharges residual gas in one adsorption tower 3 from the inlet side of the hydrogen rich gas B among the plurality of adsorption towers 3 while stopping the purification of the hydrogen rich gas. By repeating the procedure of supplying the hydrogen rich gas B from the inlet side into the inside 3, the control of swinging the residual gas between the plurality of adsorption towers 3 is performed. 1 and 2, the inlet side of the hydrogen rich gas B is below the adsorption tower 3, and the outlet side of the hydrogen rich gas B is above the adsorption tower 3. That is, the hydrogen rich gas B flows in the adsorption tower 3 from the bottom to the top.

  As shown in FIG. 2, this control is performed by a swing line 101 that circulates between the hydrogen rich gas inlet sides of the plurality of adsorption towers 3, a swing pump P <b> 1 disposed in the swing line 101, and a plurality of adsorption towers. 3 and the equilibrium line 102 which distribute | circulates the exit sides of hydrogen rich gas. The specific procedure of the control will be described in the hydrogen gas production method described later.

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

  The hydrogen gas production method produces high-purity hydrogen gas from a hydrogen-rich gas containing an impurity gas other than hydrogen gas and hydrogen by purification using an adsorption tower. The hydrogen gas production method includes a step of performing a dehydrogenation reaction of the organic hydride A by heating in the presence of a catalyst (dehydrogenation reaction step), and cooling from a mixed gas of the aromatic compound and hydrogen discharged in the dehydrogenation reaction step. The step of gas-liquid separation of the aromatic compound (gas-liquid separation step), the step of purifying the hydrogen-rich gas B obtained in the gas-liquid separation step with the adsorption tower 3 (hydrogen-rich gas purification step), and the adsorption tower 3 A regeneration step (adsorption tower regeneration step). Further, in the hydrogen gas production method, while the purification of the hydrogen rich gas is stopped, the residual gas in one adsorption tower 3 among the plurality of adsorption towers 3 is discharged from the inlet side of the hydrogen rich gas B, and the other adsorption towers are exhausted. 3 is provided with a step (swing step) of swinging the residual gas between the plurality of adsorption towers 3 by repeating the procedure of supplying the hydrogen rich gas B from the inlet side.

<Dehydrogenation reaction process>
In the dehydrogenation reaction step, the organic hydride A is dehydrogenated using the reactor 1 by heating in the presence of a catalyst.

<Gas-liquid separation process>
In the gas-liquid separation step, the separator 2 is used to gas-liquid separate the mixed gas of the aromatic compound and hydrogen discharged from the reactor 1 into a mixed gas containing the aromatic compound and hydrogen to obtain a hydrogen rich gas B. . This gas-liquid separation is performed while the gas flowing through the separator 2 is cooled by the refrigerant. In this way, by cooling the gas flowing inside the separator 2 in the gas-liquid separation step, the aromatic compound and hydrogen are easily separated, and the concentration of the aromatic compound in the separated gas is reduced.

<Hydrogen rich gas purification process>
In the hydrogen rich gas purification step, the hydrogen rich gas B is purified using the adsorption tower 3 to obtain high purity hydrogen gas. In the hydrogen rich gas purification step, the hydrogen gas may be purified while the gas flowing through the adsorption tower 3 is cooled by the refrigerant. Thus, by cooling the gas flowing through the adsorption tower 3 during adsorption, the effective adsorption amount of impurities by the adsorbent increases, the necessary amount of adsorbent is reduced, and the apparatus can be miniaturized.

  In the adsorption tower 3, impurities in the hydrogen rich gas B are adsorbed on the adsorbent, and the saturated adsorption portion of the adsorbent increases. Therefore, in order to prevent impurities from being mixed into the product gas E, it is necessary to stop the adsorption operation while the unadsorbed portion of the adsorbent remains.

<Adsorption tower regeneration process>
In the adsorption tower regeneration step, the adsorption tower 3 is regenerated using high-purity hydrogen gas as a purge gas, and off-gas is discharged. The hydrogen gas used as the purge gas may be obtained by the hydrogen gas production method or may be a hydrogen gas prepared in advance.

  Specifically, in the regeneration of the adsorption tower, the gas in the adsorption tower is discharged from the off-gas discharge line, and the pressure is reduced to normal pressure. At this time, by providing a void on the product gas outlet side of the adsorption tower, hydrogen present in the void is used for purging the adsorbent, contributing to desorption of impurities such as aromatic hydrocarbons.

  After the pressure is reduced to normal pressure, the gas in the adsorption tower is sucked by a vacuum pump, and the adsorption tower is decompressed to a negative pressure. Thereafter, the adsorbent is further regenerated by operating the vacuum pump and introducing purge gas into the adsorption tower while maintaining the inside of the adsorption tower at a negative pressure. By suctioning with a vacuum pump, some of the impurities in the gas present in the gap of the adsorbent are removed, and the partial pressure decreases, so that the adsorption equilibrium shifts to the desorption side. It becomes easy to reproduce. In this vacuum suction operation, the hydrogen gas present in the gap between the adsorbents and the hydrogen present in the voids move to the exhaust side, thereby acting as purge gas, contributing to the progress of attachment / detachment of impurities. After regeneration of the adsorbent, a pressure equalizing operation is performed, and after that, after repressurization by introducing the product gas E into the adsorption tower, the adsorption operation is performed again.

  At the end of the purge, the adsorbent is not completely regenerated and some of the adsorbed impurities remain, but the unsaturated adsorbed portion of the adsorbent increases compared to the end of adsorption. Even if the process moves to the adsorption process again, a sufficient adsorption capacity is recovered. In addition, to reduce the adsorption capacity of the adsorbent due to repeated adsorption, depressurization, decompression, and purge, the product gas purity at the time of adsorption can be reduced by setting a shorter adsorption time corresponding to the decrease in the adsorption capacity. Can be secured. It is also possible to ensure the purity of the product gas by reducing the amount of hydrogen-rich gas introduced into the adsorption tower and lowering the linear velocity LV of the gas in the adsorption tower, rather than setting the adsorption time short. is there.

  The hydrogen-rich gas purification step and the adsorption tower regeneration step are alternately performed while shifting the cycle of the plurality of adsorption towers 3a and 3b.

<Swing process>
The swing process is performed while the purification of the hydrogen rich gas B is stopped, and is performed immediately after the stop of the purification until the restart of the purification.

  In the swing process, first, as shown in the left diagram of FIG. 2, the residual gas in one adsorption tower 3a is transferred into another adsorption tower 3b by the swing line 101 and the swing pump P1. At this time, the residual gas is discharged from the inlet side (lower side) of the hydrogen-rich gas of the discharge side adsorption tower 3a and supplied from the inlet side of the hydrogen-rich gas of the supply side adsorption tower 3b. Further, since the hydrogen rich gas outlet sides (upper side) of these adsorption towers circulate in the equilibrium line 102, the gas staying on the hydrogen rich gas outlet side of the adsorption tower is the residual gas swing pump P1. It moves in the direction opposite to the transfer by (direction from the supply-side adsorption tower 3b to the discharge-side adsorption tower 3a), and the pressure between the two adsorption towers is kept in equilibrium. Thereby, transfer of residual gas can be performed easily.

  Next, as shown in the right figure of FIG. 2, the residual gas is transferred in the reverse direction. That is, the residual gas in the adsorption tower 3b to which the residual gas is first supplied is transferred into the other adsorption tower 3a by the swing line 101 and the swing pump P1. This transfer is performed in exactly the same procedure as the first transfer except that the moving direction of the residual gas is reversed.

  By repeating the above transfer alternately, the residual gas swings between the plurality of adsorption towers 3. By this swing, the boundary of the hydrogen-rich gas outlet side of the adsorption breakthrough portion Q formed in the adsorbent repeatedly rises and falls inside the tower, but the adsorption breakthrough portion Q is suppressed to a certain size or less. . Therefore, the diffusion of impurities from the adsorbent is suppressed, and the amount of impurities released into the adsorption tower during the purification stop can be reduced.

  The linear velocity in the adsorption tower at the time of the swing process is preferably set to be equal to or lower than the linear velocity in the normal hydrogen rich gas purification process. For example, the lower limit of the linear velocity is preferably 5%. Further, the upper limit of the linear velocity is preferably 90%, and more preferably 50%.

  Moreover, it is preferable that the gas transfer amount in one transfer is not more than the volume of the void portion in the adsorption tower. For example, the lower limit of the gas transfer amount is preferably 5% of the volume of the void portion in the adsorption tower, and more preferably 30%. Moreover, as an upper limit of the said gas transfer amount, 95% is preferable and 60% is more preferable.

  The swing interval (interval from the end of the transfer of one residual gas to the start of the transfer of the next residual gas) can be changed depending on the combination of adsorbate and adsorbent, temperature, pressure, etc. The adsorption time in the rich gas purification step is preferably 10 times or less, more preferably 3 times or less. As a specific example, if the adsorption time in the hydrogen rich gas purification step is 5 minutes, the swing interval is preferably 50 minutes or less, and more preferably 15 minutes or less.

  The pressure and temperature in the adsorption tower during the swing process can be changed according to the combination of the adsorbate and the adsorbent, the temperature and pressure during the purification, and the like. By increasing the pressure and decreasing the temperature, the diffusion rate of the gas component can be reduced. On the other hand, when the pressure is increased excessively, the apparatus cost and the operating cost increase. Therefore, the upper limit of the pressure in the adsorption tower during the swing process is preferably 1 Mpa. Moreover, as a minimum of the adsorption tower internal pressure at the time of a swing process, the pressure +100 Pa at the time of refinement | purification is preferable, and +500 Pa is more preferable.

  The temperature in the adsorption tower at the time of the swing process can be, for example, not more than the temperature at the time of purification, and the upper limit of the temperature in the adsorption tower at the time of the swing process is preferably -5 ° C. at the time of purification. A temperature of −10 ° C. is more preferred.

  In addition, although demonstrated using two adsorption towers in FIG. 2, when using three or more adsorption towers, a swing process is performed by switching the adsorption tower which discharges | emits residual gas, and the adsorption tower to supply in order. Can do. Moreover, when using four or more adsorption towers, you may transfer a residual gas simultaneously with two or more sets of adsorption towers.

  Further, the equilibrium line 102 that circulates the hydrogen rich gas outlet sides of the adsorption tower is not essential, and can be omitted if the residual gas can be discharged from the adsorption tower and supplied to another adsorption tower. For example, if the inside of the adsorption tower is pressurized, the residual gas can be discharged from the swing line 101 without the equilibrium line 102.

<Advantages>
According to the hydrogen gas production method and the hydrogen gas production apparatus, the adsorption breakthrough portion formed in the adsorbent of each adsorption tower can be obtained by swinging the residual gas by taking in and out the hydrogen rich gas from the inlet side during the purification stop. It can be kept at a certain size. As a result, the diffusion of impurities during the purification stop is suppressed, and the contamination of the impurities into the purified gas discharged after the restart of the stop is suppressed. As a result, the hydrogen gas production method and the hydrogen gas production apparatus can suppress a reduction in the recovery rate of hydrogen gas and shorten the startup time until hydrogen gas supply.

[Other Embodiments]
The hydrogen gas production method and the hydrogen gas production apparatus of the present invention are not limited to the above embodiment.

  In the embodiment described above, the mixed gas after the dehydrogenation reaction is gas-liquid separated. However, this gas-liquid separation is not essential and can be omitted. That is, the mixed gas discharged by the dehydrogenation reaction may be supplied as it is to the adsorption tower as a hydrogen rich gas.

  In the above embodiment, the hydrogen-rich gas is obtained by gas-liquid separation of an aromatic compound from organic hydride, but the hydrogen-rich gas is generated by steam reforming, autothermal reforming or partial oxidation reforming of hydrocarbon gas. It is also possible to use a reformed gas or a plant off-gas having a high hydrogen content. When reformed gas is used as the hydrogen-rich gas, a reformer that reforms the raw material gas is used instead of the reactor and separator of the above embodiment, and a heat source is supplied to the reformer as necessary. The

  The raw material gas used for the reforming reaction can be appropriately selected from a compound containing carbon and hydrogen in the molecule or a mixture thereof. Examples of the compound include 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, and the like. Can be mentioned.

  As described above, when the hydrogen gas production method and the hydrogen gas production apparatus repeatedly stop and restart the hydrogen gas purification, the hydrogen gas production rate and the hydrogen gas production apparatus can suppress the decrease in the recovery rate of hydrogen gas and shorten the startup time. It is suitably used for the purpose of supplying hydrogen.

DESCRIPTION OF SYMBOLS 1 Reactor 2 Separator 3, 3a, 3b Adsorption tower 4 Product gas buffer tank 101 Swing line 102 Equilibrium line A Organic hydride B Hydrogen rich gas D Drain E Product gas P1 Swing pump Q Adsorption breakthrough part

Claims (6)

A hydrogen gas production method for producing high-purity hydrogen gas by refining with a plurality of adsorption towers from hydrogen-rich gas containing impurity gas other than hydrogen gas and hydrogen,
While stopping the purification of the hydrogen-rich gas, a procedure for discharging the residual gas in one of the plurality of adsorption towers from the inlet side of the hydrogen-rich gas and supplying the other adsorption tower from the inlet side of the hydrogen-rich gas A hydrogen gas production method comprising a step of swinging residual gas between the plurality of adsorption towers by repeating.   2. The method for producing hydrogen gas according to claim 1, wherein, in the swing step, the hydrogen rich gas outlet sides of the adsorption tower for discharging the residual gas and the adsorption tower for supplying the residual gas are circulated. The plurality of adsorption towers are PSA type,
The method for producing hydrogen gas according to claim 1 or 2, wherein in the swing step, the pressure in the adsorption tower is made higher than that during purification. The plurality of adsorption towers are TSA type,
The method for producing hydrogen gas according to claim 1 or 2, wherein in the swing step, the temperature in the adsorption tower is made lower than that during purification. Further comprising a step of dehydrogenating the organic hydride by heating in the presence of a catalyst,
The method for producing hydrogen gas according to any one of claims 1 to 4, wherein the hydrogen-rich gas is a gas discharged in the dehydrogenation reaction step. A hydrogen gas production method for producing high-purity hydrogen gas by purification with an adsorption tower from hydrogen-rich gas containing impurity gas other than hydrogen gas and hydrogen,
While stopping the purification of the hydrogen-rich gas, a procedure for discharging the residual gas in one of the plurality of adsorption towers from the inlet side of the hydrogen-rich gas and supplying the other adsorption tower from the inlet side of the hydrogen-rich gas A hydrogen gas production apparatus comprising: a control mechanism that performs control to swing residual gas between the plurality of adsorption towers by repeating.

Images