JP2012087012A - Operation method of psa device for producing high purity hydrogen gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation method of a PSA device for producing high purity hydrogen gas capable of reducing impurities (especially CO) in produced hydrogen gas even when being restarted next time after stopping continuous production of the high purity hydrogen gas, and reducing loss of product hydrogen gas.SOLUTION: In this method, the operation is stopped in the state where each adsorption tower 1a, 1b, 1c has higher pressure than the atmospheric pressure, and in the state in which at least one adsorption tower 1b in each adsorption tower 1a, 1b, 1c has pressure for adsorbing unnecessary gas from hydrogen-containing gas.

Description

  The present invention relates to a method for operating a PSA apparatus (hereinafter also simply referred to as “PSA apparatus”) that produces high-purity hydrogen gas for fuel cells.

  In recent years, in conjunction with global warming prevention measures, the departure of energy from crude oil dependence has become an important issue on a global scale, and efforts toward the practical application of fuel cells using hydrogen gas as an energy source Has become active.

  In view of such a situation, a PSA apparatus for producing high-purity hydrogen gas for fuel cells has been developed (see, for example, Patent Document 1).

  In addition, at the initial stage where hydrogen infrastructure is established and fuel cell vehicles are widely used, the operation time of hydrogen production equipment is expected to be still short. Therefore, it is considered that the hydrogen production apparatus is frequently started and stopped. Under such circumstances, a technology capable of reducing impurities in the produced hydrogen gas even when the hydrogen production apparatus for continuously producing high-purity hydrogen gas is stopped and restarted next time has been developed (for example, , See Patent Document 2).

JP 2008-63152 A JP 2009-154079 A

  The PSA device disclosed in Patent Document 1 is very excellent as a technique for continuously producing high-purity hydrogen gas for fuel cells, but after the PSA device was temporarily stopped, it was restarted next time. There has been a problem that no countermeasure has been taken against problems that may occur at the time {that is, problems in which impurities (particularly CO) are mixed into the produced hydrogen gas}.

  Moreover, in the hydrogen production apparatus disclosed in Patent Document 2, after the stop signal is input, the adsorbate in the adsorbent is removed while repeating equalization and depressurization in two or more adsorption towers. There was a problem that a large amount of hydrogen gas (product hydrogen gas) was lost.

  The object of the present invention is to reduce impurities (especially CO) in the produced hydrogen gas even after the next restart after stopping the continuous production of high-purity hydrogen gas, and to produce product hydrogen. An object of the present invention is to provide a method of operating a PSA apparatus for producing high-purity hydrogen gas that can reduce gas loss.

In order to achieve this object, the invention according to claim 1 of the present invention provides:
Adsorbent bed provided by laminating three or more adsorption towers and a carbon-based adsorbent layer for adsorbing CO ₂ in the respective adsorption towers of the three or more adsorption towers. High-purity hydrogen gas is obtained by adsorbing and removing unnecessary gas including CO gas from the hydrogen-containing gas by supplying a hydrogen-containing gas from at least the CO adsorbent layer side of each adsorption tower into the adsorption tower. A high-purity hydrogen comprising: a step of producing; and a step of desorbing the unnecessary gas adsorbed on the adsorbent bed by reducing the inside of the adsorption tower to less than atmospheric pressure from the CO adsorbent layer side of each adsorption tower A method for operating a PSA device for gas production,
In the PSA apparatus, all the adsorption towers in each of the adsorption towers are at atmospheric pressure or higher, and at least one of the adsorption towers is in the state of the adsorption pressure of the unnecessary gas from the hydrogen-containing gas. An operation method of the PSA apparatus for producing high purity hydrogen gas, characterized in that the operation is stopped.

The invention according to claim 2 is the invention according to claim 1,
The CO adsorbent is a material in which copper (I) halide and / or copper (II) halide is supported on one or more carriers selected from the group consisting of silica, alumina, and polystyrene resin, or An adsorbent obtained by reducing this material.

The invention according to claim 3 is the invention according to claim 1 or 2,
Before all the adsorption towers in each of the adsorption towers are at atmospheric pressure or higher and at least one of the adsorption towers is stopped from the hydrogen-containing gas at the adsorption pressure of the unnecessary gas. Further, the supply of the hydrogen-containing gas into the adsorption tower is stopped, and the adsorbent bed is regenerated while supplying a cleaning gas from the carbon-based adsorbent layer side of each adsorption tower.

As described above, according to the operation method of the high purity hydrogen gas production PSA apparatus according to the present invention,
The operation of the PSA apparatus is performed in a state where all the adsorption towers of each adsorption tower are at atmospheric pressure or higher, and at least one of the adsorption towers is at the adsorption pressure of the unnecessary gas from the hydrogen-containing gas. Therefore, it is possible to reduce impurities (especially CO) in the produced hydrogen gas even after restarting the next time after continuous production of high-purity hydrogen gas is stopped. In addition, loss of product hydrogen gas can be reduced.

It is a schematic explanatory drawing of the adsorption tower of the PSA apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which illustrates typically the outline | summary of a structure of the PSA apparatus by which the adsorption tower shown in FIG. 1 was employ | adopted. It is a characteristic view which shows transition of the impurity concentration and hydrogen concentration with respect to the elapsed time after starting in Example 1 using the PSA apparatus shown in FIG. It is a characteristic view which shows transition of the impurity concentration and hydrogen concentration with respect to the elapsed time after starting in Example 2 using the PSA apparatus shown in FIG. It is a characteristic view which shows transition of the impurity concentration and hydrogen concentration with respect to the elapsed time after starting in the comparative example 1 using the PSA apparatus shown in FIG. It is a characteristic view which shows transition of the impurity concentration and hydrogen concentration with respect to the elapsed time after starting in Example 3 using the PSA apparatus shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is a schematic explanatory view of an adsorption tower of a PSA apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory view schematically explaining the outline of the configuration of the PSA apparatus employing the adsorption tower shown in FIG. .

  In FIG. 1 (a), reference numeral 1 denotes an adsorption tower in which a raw material gas supply channel 6 is connected to the lower part and a processing gas discharge channel 7 is connected to the upper part. An adsorbent bed 2 is provided in which a CO adsorbent layer 3 and a carbon-based adsorbent layer 4 are laminated in this order (from the upstream side toward the downstream side in the flow direction of the hydrogen-containing gas A). Then, as shown in FIG. 1B, when the adsorbent bed 2 is regenerated, the cleaning gas C is reversed in the order of the carbon-based adsorbent layer 4 and the CO adsorbent layer 3 in the reverse direction of the flow of the hydrogen-containing gas A. It is configured to be distributed.

By adopting such a configuration, only CO in the hydrogen-containing gas A is adsorbed to the CO adsorbent during the adsorption operation, and CO ₂ and CH _{4 that} have passed through the CO adsorbent are adsorbed to the subsequent carbon-based adsorbent. In the regeneration operation, unnecessary gas components (CO ₂ , CH ₄ ) adsorbed on the carbon-based adsorbent are desorbed, and this desorbed component acts as a cleaning gas for the CO adsorbent, which is necessary for the regeneration of the CO adsorbent. It is possible to reduce the amount of cleaning gas (product hydrogen gas) used, increase the hydrogen recovery rate, and reduce the hydrogen purification cost.

Examples of the CO adsorbent include copper (I) halide and / or one or more carriers selected from the group consisting of porous silica, porous alumina, and polystyrene-based resin that do not substantially adsorb CO _2. Alternatively, a material supporting copper (II) halide, or a material obtained by reducing this material may be used.

This prevents unnecessary gas components (CO ₂ , CH ₄ ) desorbed from the carbon-based adsorbent layer 4 from being re-adsorbed to the CO adsorbent layer 3 during regeneration of the adsorbent bed 2. Since these unnecessary gas components are also effectively used as part of the cleaning gas, the effect of increasing the hydrogen recovery rate can be obtained.

  Moreover, activated carbon and CMS (carbon molecular sieve) can be used as the carbon-based adsorbent.

In addition, since CO ₂ , CH ₄ , CO, and H ₂ O are also mixed as impurities in the normal reformed gas (hydrogen-containing gas A) used as the raw material gas, the CO adsorbent layer 3 and the carbon-based adsorbent In order to protect the layer 4 from the influence of moisture, an adsorbent layer such as activated alumina for removing water can be provided in the same adsorption tower or as a separate adsorption tower in the previous stage of the adsorbent bed 2.

  It is desirable to regenerate the adsorbent bed 2 on the vacuum side (negative pressure side) lower than the atmospheric pressure. It is possible to regenerate the adsorbent by performing the adsorption operation at high pressure, reducing the pressure to atmospheric pressure and flowing the cleaning gas C (product hydrogen gas), but using a vacuum pump to reduce the pressure to the lower vacuum side. Thus, the CO gas molecules that are strongly chemically adsorbed to the CO adsorbent are easily desorbed, and the amount of product hydrogen gas used for cleaning can be further reduced, and the hydrogen recovery rate is further improved. The degree of vacuum is preferably 50 kPa (absolute pressure) or less, and more preferably 20 kPa (absolute pressure) or less. The higher the degree of vacuum is, the more the amount of cleaning gas can be reduced. On the other hand, the required vacuum pump power increases, so that a degree of vacuum of 1 kPa (absolute pressure) or more is desirable considering the total running cost.

  Hereinafter, an outline of an example of the configuration of the PSA apparatus in which the adsorption tower is employed will be described in detail with reference to a schematic explanatory diagram shown in FIG. The PSA apparatus of this example has three adsorption towers 1a, 1b, and 1c, and the adsorbent bed 2 is provided in each of the adsorption towers 1a to 1c. Line 101 is an introduction line for hydrogen-containing gas A. The line 101 and the adsorption towers 1a to 1c are connected to each other through a valve A1, a valve B1, and a valve C1, respectively.

  The line 102 is a line used for depressurizing the inside of the adsorption tower. In order to further depressurize the pressure of the adsorption tower after completion of pressure equalization (see the pressure equalization step described later) to near atmospheric pressure (refer to the first pressure reduction step described later). Used for. The line 102 is connected to the adsorption towers 1a to 1c through the valve A2, the valve B2, and the valve C2, respectively.

  The line 103 is a line for depressurizing the adsorption tower that has been depressurized to near atmospheric pressure (first depressurizing step) to a negative pressure below atmospheric pressure {less than 50 kPa (absolute pressure)} (see the second depressurizing step described later). Yes, the vacuum pump 10 and the adsorption towers 1a to 1c are connected via a valve A3, a valve B3, and a valve C3, respectively. The exhaust gas of the vacuum pump 10 in the lines 102 and 103 is temporarily stored in the buffer tank 8. The gas stored in the buffer tank 8 can be effectively used as a calorie gas, for example, as a fuel for a reformer when the hydrogen-containing gas A is produced.

  A line 104 is a recovery line for high-purity hydrogen gas B obtained by removing unnecessary gas from the hydrogen-containing gas A in the adsorption tower, and the adsorption towers 1a to 1c are respectively connected via a valve A5, a valve B5, and a valve C5. The collected high purity hydrogen gas B is temporarily stored in the buffer tank 9.

  The line 105 is a line for cleaning and regenerating the adsorption tower after the unnecessary gas adsorption step from the hydrogen-containing gas A is completed and the pressure is reduced to the negative pressure (vacuum side) (see the second pressure reduction step described later). The adsorption towers 1a to 1c and the buffer tank 9 are connected via a valve D1, a valve A6, a valve B6, and a valve C6, and a part of the recovered high-purity hydrogen gas B is used as a cleaning gas for regeneration of the adsorbent ( Use cleaning gas C).

  The line 106 is a line for performing pressure equalization (pressure equalization step), and performs gas pressure equalization between the adsorption tower after the unnecessary gas adsorption step and the adsorption tower after the adsorbent regeneration step (described later). Used for. Specifically, among the valves A4, B4, and C4, two valves connected to the two towers that perform pressure equalization are opened, and the other valves are closed, so that the pressure in the two adsorption towers can be equalized. Become.

  First, specific procedures for continuous operation of unnecessary gas adsorption removal, equalization between adsorption towers, desorption of unwanted gas by decompression, regeneration of adsorbent and pressure increase of adsorption tower (standby state for removal of unwanted gas adsorption) Explained. Although only the operation procedure of the adsorption tower 1a will be described below, the operation is cyclically performed using three towers of the adsorption towers 1a, 1b and 1c as shown in the time table of Table 1. Thereby, continuous manufacture of the high purity hydrogen gas B is attained.

1) [Unnecessary gas adsorption step]: Hydrogen-containing gas A whose pressure has been increased to about 1.0 MPa (absolute pressure) is supplied from the source gas supply channel 6a side (the CO adsorbent layer (not shown) side of the adsorption tower 1a). Then, unnecessary gas is removed by an adsorbent, and high purity hydrogen gas B is recovered (valves A2, A3, A4, A6: closed, valves A1, A5: open).

2) [Pressure equalizing step]: The unnecessary gas adsorption operation (unnecessary gas adsorption step) is completed, and a part of the gas in the adsorption tower 1a is transferred to the adsorption tower 1c after the regeneration operation (adsorbent regeneration step). Here, for example, when an unnecessary gas adsorption operation is performed at 1.0 MPa (absolute pressure) in the adsorption tower 1a, the adsorbent in the adsorption tower 1c is regenerated under reduced pressure, so that the internal pressures of the adsorption towers 1a and 1c in this step. Are about 0.5 MPa (absolute pressure) (valves A1, A2, A3, A5, A6, valves C1, C2, C3, C5, C6: closed, valve A4, valve C4: opened).

3) [First decompression step]: The internal pressure of the adsorption tower 1a after the pressure equalization operation (decompression step) is reduced to atmospheric pressure (valves A1, A3, A4, A5, A6: closed, valve A2: opened).

4) [Second depressurization step]: The adsorption tower 1a depressurized to atmospheric pressure is further depressurized to a negative pressure (less than atmospheric pressure) using the vacuum pump 10 (valves A1, A2, A4, A5, A6: closed, valve A3: Open), unnecessary gas is desorbed.

5) [Adsorbent regeneration step]: The cleaning gas C (a part of the high-purity hydrogen gas B) is supplied under reduced pressure to regenerate the adsorbent (valves A1, A2, A4, A5: closed, valves A3, A6). , Valve D1: open).

6) [Pressure equalization step]: Partial transfer of the gas in the adsorption tower 1b after completion of the unnecessary gas adsorption step to the adsorption tower 1a after regeneration of the adsorbent (valve A1, A2, A3, A5, A6, valve) B1, B2, B3, B5, B6: closed, valve A4, valve B4: open).

7) [Pressure increasing step]: High-purity hydrogen gas B is introduced into the adsorption tower 1a from the buffer tank 9, and the pressure in the adsorption tower 1a is increased to a pressure at which unnecessary gas adsorption operation is performed (valves A1, A2, A3). A4, A6: closed, valve A5: open).

8) The operation steps 1) to 7) are repeated, and unnecessary gas adsorption removal, equalization pressure between adsorption towers, unnecessary gas desorption by decompression, adsorbent regeneration and adsorption tower pressure increase (standby for unnecessary gas adsorption removal) Repeat the continuous operation.

  The PSA apparatus according to the present embodiment is a process for regenerating an adsorbent under a negative pressure (vacuum side) further reduced from atmospheric pressure, and adsorbing and removing an unnecessary gas from a hydrogen-containing gas B under a high pressure. Unnecessary gas removal from B can be realized with a compact apparatus, and the hydrogen recovery rate can be increased.

Next, in the operation method of the PSA apparatus according to the present invention, how to stop the continuous production of high-purity hydrogen gas, the next restart from this stopped state, and the elapsed time after the restart The transition of the impurity (CO, CH ₄ , CO ₂ ) concentration and the hydrogen concentration in the high-purity hydrogen gas B with respect to the above will be described below together with examples.

Example 1
First, as hydrogen-containing gas A (raw material gas), commercially available bomb gas is mixed and CO ₂ : 19.7%, CH ₄ : 2.8%, CO: 0.4%, H ₂ : 77.1% A simulated reformed gas is prepared, this gas is introduced into the PSA apparatus through the line 101 at a flow rate of 0.8 Nm ³ / h, the PSA apparatus is operated according to the operation procedure described in the above embodiment, and the high-purity hydrogen gas B A continuous purification test was conducted.
<Used adsorbent>
Carbon-based adsorbent: activated carbon (G2X manufactured by Nippon Envirochemical)
CO adsorbent: Copper (I) chloride supported on porous alumina (co-developed by Kansai Thermal Chemical)
<Adsorption temperature> 40 ° C
<Adsorption pressure> 1.0 MPaG (absolute pressure)
<Regeneration pressure> 20 kPa (absolute pressure)

  After a stop signal is input to the controller (not shown) in the PSA apparatus in the state where such a high-purity hydrogen gas B is continuously purified, for example, the above-mentioned Table 1 In the state shown in the time table (adsorption tower 1a is a pressure equalization step, adsorption tower 1b is an unnecessary gas adsorption step, and adsorption tower 1c is a pressure equalization step). That is, all of the adsorption towers 1a, 1b, and 1c are in an atmospheric pressure or higher state, and at least one of the adsorption towers 1a, 1b, and 1c is replaced with the hydrogen-containing gas A. It is configured to stop in the state of the unnecessary gas adsorption pressure. Here, the adsorption pressure of the present invention means a pressure used when adsorbing unnecessary gas, but it is different from the pressure at which the adsorption operation is actually performed as long as the adsorption can be started without delay at the time of restart. Also good.

FIG. 3 shows the results of examining the transition of the impurity (CO, CH ₄ , CO ₂ ) concentration and the hydrogen concentration with respect to the elapsed time after the restart after being left at room temperature overnight from such a stop state. Shown in the figure.

As shown in FIG. 3, the hydrogen concentration in the high-purity hydrogen gas B already satisfies the predetermined hydrogen concentration of 99.99% or more immediately after the restart. In addition, the noted CO has not been mixed into the high-purity hydrogen gas B immediately after restarting, and sufficiently satisfies CO ≦ 1 ppm required as hydrogen gas for fuel cells. Further, CH ₄ and CO ₂ are somewhat mixed into the high-purity hydrogen gas B immediately after restarting, but there is no problem when considering the level required by the hydrogen gas for the fuel cell. As described above, when the operation method (Example 1) of the PSA device according to the present invention is adopted, the hydrogen produced when the continuous production of the high purity hydrogen gas is stopped and then restarted next time. Impurities (particularly CO) in the gas can be reduced.

  As described above, in the operation method (Example 1) of the PSA device according to the present invention, the adsorbate in the adsorbent is removed while repeating the pressure equalization and depressurization (decompression), and then the PSA device is continuously operated. Since it is not stopped, the produced hydrogen gas (product hydrogen gas) is not lost in large quantities. This is because when moving from step number 5 to step number 6 shown in the time table of Table 1 above, the adsorption tower 1c shifts from the pressure equalizing step to the pressure increasing step. There is no need to increase the pressure using hydrogen, and the loss of produced hydrogen gas (product hydrogen gas) can be reduced.

(Example 2)
Since the second embodiment differs from the first embodiment in the stop timing after the stop signal is input, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described in detail. That is, in the second embodiment, after the stop signal is input, for example, the stop is performed at the timing of switching from step number 5 to step number 6 shown in the time table of Table 1 above. Therefore, also in such a case, as in the case of Example 1, all the adsorption towers of the adsorption towers 1a, 1b, and 1c are in the state of the atmospheric pressure or more, and the adsorption towers 1a, 1b, and 1c. The at least one adsorption tower 1b is configured to stop at the adsorption pressure of the unnecessary gas from the hydrogen-containing gas A.

FIG. 4 shows the results of examining the transition of the impurity (CO, CH ₄ , CO ₂ ) concentration and the hydrogen concentration with respect to the elapsed time after the restart after being left at room temperature overnight from such a stop state. Shown in the figure.

As shown in FIG. 4, the hydrogen concentration in the high-purity hydrogen gas B already satisfies the predetermined hydrogen concentration of 99.99% or more immediately after the restart, as in the case of the first embodiment. Further, as in the case of Example 1, the noted CO is not mixed into the high-purity hydrogen gas B immediately after the restart and sufficiently satisfies CO ≦ 1 ppm required as the hydrogen gas for the fuel cell. ing. Further, CH ₄ and CO ₂ are somewhat mixed into the high-purity hydrogen gas B immediately after restarting, but there is no problem when considering the level required by the hydrogen gas for the fuel cell. As described above, even when the operation method of the PSA device according to the present invention (Example 2) is adopted, the hydrogen produced when the continuous production of high-purity hydrogen gas is stopped and then restarted next time. Impurities (particularly CO) in the gas can be reduced. Further, as in the case of Example 1 described above, it is possible to reduce the loss of the produced hydrogen gas (product hydrogen gas).

(Comparative Example 1)
Since the comparative example 1 is different from the first embodiment in the stop timing after the stop signal is input, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described in detail. That is, in the first comparative example, after the stop signal is input, for example, the state as in step number 4 shown in the time table of Table 1 above (the adsorption tower 1a is the unnecessary gas adsorption step and the adsorption tower 1b is boosted) Step, the adsorption tower 1c is stopped at the regeneration step). That is, among the adsorption towers 1a, 1b, and 1c, the adsorption tower 1a is in the state of adsorption pressure of the unnecessary gas from the hydrogen-containing gas A, but the adsorption tower 1c is in a negative pressure state, and all the adsorption towers The inside is not over atmospheric pressure.

FIG. 5 shows the results of examining the transition of the impurity (CO, CH ₄ , CO ₂ ) concentration and the hydrogen concentration with respect to the elapsed time after the restart after being left at room temperature overnight from such a stop state. Shown in the figure.

As shown in FIG. 5, the hydrogen concentration in the high-purity hydrogen gas B cannot satisfy the predetermined hydrogen concentration of 99.99% or more immediately after the restart as in the first and second embodiments. . In addition, as noted in the first and second embodiments, the focused CO eliminates mixing into the high-purity hydrogen gas B immediately after restarting, and satisfies CO ≦ 1 ppm required as hydrogen gas for fuel cells. It is not possible. Further, CH ₄ and CO ₂ are mixed into the high-purity hydrogen gas B for a while after the restart, and this is a problem when considered from the level required by the fuel cell hydrogen gas. In particular, CH ₄ becomes 3000 ppm or more immediately after restarting. This is stopped in a state like Step No. 4 shown in the time table of Table 1 above, so in the adsorption tower 1a in which the adsorption of impurities (CO, CH ₄ , CO ₂ ) has progressed very much, overnight. This is because if left at room temperature, it diffuses to the downstream side {activated carbon (carbon adsorbent) side} of the adsorption tower 1a and is mixed into the product hydrogen gas after restarting. Further, the adsorption tower 1c is kept overnight in a negative pressure state, and after restarting, a pressure equalizing operation is performed from the adsorption tower 1a toward the adsorption tower 1c, so that the downstream side of the adsorption tower 1a {activated carbon (carbon-based adsorbent) Impurities (CO, CH ₄ , CO ₂ ) diffused to the side} also reach the adsorption tower 1c and increase in the amount of product hydrogen gas. Furthermore, since the adsorption tower 1c is kept overnight in a negative pressure state, the pressure rises with time, and it seems that there is gas mixing from the outside of the adsorption tower 1c. In addition, after restarting, the adsorption tower 1b is switched from the pressure increasing step to the unnecessary gas adsorption step, and the adsorption tower 1b is also in communication with the adsorption tower 1a that was in the unnecessary gas adsorption step for a short time. Therefore, impurities (CO, CH ₄ , CO ₂ ) are mixed into the product hydrogen gas.

(Example 3)
The difference between the third embodiment and the first embodiment is the pre-processing operation until the stop after the stop signal is input. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, The description is omitted, and only different parts are described in detail. That is, in the third embodiment, after the stop signal is input, for example, before stopping in the state of step number 5 shown in the time table of Table 1, the hydrogen-containing gas A (source gas) The supply to the adsorption tower 1a is stopped, and the cleaning gas C is supplied from the processing gas discharge channels 7a, 7b, 7c side (carbon adsorbent layer (not shown) side of the respective adsorption towers 1a, 1b, 1c). The purpose is to regenerate each adsorbent bed.

FIG. 6 shows the results of examining the transition of the impurity (CO, CH ₄ , CO ₂ ) concentration and the hydrogen concentration with respect to the elapsed time after the restart after being left at room temperature overnight from such a stopped state. Shown in the figure.

As shown in FIG. 6, the hydrogen concentration and impurity (CO, CH ₄ , CO ₂ ) concentration in the high-purity hydrogen gas B were both better than those of Example 1 and Example 2.

In the first embodiment, only the first example, the second example, and the third example having three adsorption towers have been described as suitable examples of the operation method of the PSA apparatus according to the present invention. Without being limited thereto, after the stop signal is input, all the adsorption towers of each adsorption tower are in a state of atmospheric pressure or higher, and at least one of the adsorption towers is a hydrogen-containing gas. a (raw material gas) from unwanted gas _{(CO, CH 4, CO 2} ) in the state of adsorption pressure may be composed so as to stop. For example, it is possible to stop in a state such as step number 6 shown in the time table of Table 1 above. With such a configuration, after stopping the continuous production of high-purity hydrogen gas, it is possible to reduce impurities (particularly CO) in the produced hydrogen gas even when restarted next time, and It is possible to reduce the loss of product hydrogen gas.

(Embodiment 2)
The basic component of the PSA apparatus in the second embodiment is different from the basic component of the PSA apparatus in the first embodiment in that one adsorption tower is added. The same number is attached | subjected to the same component, the description is abbreviate | omitted, and only a different part is explained in full detail. In particular, by adding one adsorption tower (not shown), the operation steps as shown in the time table of Table 2 below have been devised. Detailed description.

  By performing cyclically using the adsorption towers 1a, 1b, 1c, and 1d according to the operation procedure shown in the time table of Table 2, high-purity hydrogen gas B can be continuously produced. Therefore, only the operation procedure of the adsorption tower 1a will be described below.

  Each operation step is provided in the order of “first decompression”, “second decompression”, and “regeneration” between step number 4 (equal pressure) and step number 10 (equal pressure) shown in the time table of Table 2 above. Thus, the point differs from the first embodiment. As described above, by using the four-column type, it is possible to provide a long decompression operation step, and the regeneration of the adsorbent bed is promoted.

  After the stop signal is input in the state where the high-purity hydrogen gas B is continuously produced by the operation steps shown in the time table of Table 2, for example, it is shown in the time table of Table 2 above. In step 4 (the adsorption tower 1a is a pressure equalization step, the adsorption tower 1b is an unnecessary gas adsorption step, the adsorption tower 1c is a pressure equalization step, and the adsorption tower 1d is a first pressure reduction step). By stopping in this way, as in the case of the first embodiment, all of the adsorption towers 1a, 1b, 1c, and 1d are in an atmospheric pressure or higher state, and each adsorption tower 1a, The adsorption tower 1b of 1b, 1c, and 1d is configured to stop at the adsorption pressure of the unnecessary gas from the hydrogen-containing gas A. Therefore, even in such a configuration, impurities (especially CO) in the produced hydrogen gas can be reduced when the continuous production of high-purity hydrogen gas is stopped and then restarted next time. In addition, loss of product hydrogen gas can be reduced.

(Embodiment 3)
The basic component of the PSA apparatus in the third embodiment is different from the basic component of the PSA apparatus in the first embodiment in that one adsorption tower is added as in the second embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different portions will be described in detail. In particular, by adding one adsorption tower (not shown), the operation steps as shown in the time table of Table 3 below have been devised. Detailed description.

  By performing cyclically using the adsorption towers 1a, 1b, 1c, and 1d according to the operation procedure shown in the time table of Table 3, the high-purity hydrogen gas B can be continuously produced. Therefore, only the operation procedure of the adsorption tower 1a will be described below.

  Between the step number 4 (adsorption) and step number 14 (pressure increase) shown in the time table of Table 3, “first pressure equalization”, “hold (maintain first pressure equalization state)”, “second pressure equalization” ”,“ First pressure reduction ”,“ second pressure reduction ”,“ regeneration ”,“ second pressure equalization ”,“ first pressure equalization ”, and the operation steps are provided in the order described in the second embodiment. Different. In particular, the pressure equalizing step is characterized by the provision of two pressure equalizing steps, a first pressure equalizing (0.6 MPaG) and a second pressure equalizing (0.2 MPaG). Thus, by providing two pressure equalization steps, it is possible to reduce the loss of product hydrogen gas used in the pressure equalization step.

  After the stop signal is input in a state where the high-purity hydrogen gas B is continuously produced by the operation steps shown in the time table of Table 3, for example, it is shown in the time table of Table 3 above. The “unnecessary gas adsorption step” in step numbers 1 to 4 is switched to the “pressure increase step”, and the state as in step number 5 (the adsorption tower 1a is the first pressure equalizing step, the adsorption tower 1b is the unnecessary gas adsorption step, the adsorption tower) 1c is stopped at the first pressure equalizing step, and the adsorption tower 1d is stopped at the first pressure reducing step). By stopping in this way, as in the case of the first and second embodiments, all of the adsorption towers 1a, 1b, 1c, and 1d are in an atmospheric pressure or higher state, and each adsorption tower At least one adsorption tower 1b among 1a, 1b, 1c, and 1d is configured to stop at the adsorption pressure of the unnecessary gas from the hydrogen-containing gas A. Therefore, even in such a configuration, impurities (especially CO) in the produced hydrogen gas can be reduced when the continuous production of high-purity hydrogen gas is stopped and then restarted next time. In addition, loss of product hydrogen gas can be reduced.

1, 1a, 1b, 1c: adsorption tower 2: adsorbent bed 3: CO adsorbent layer 4: carbon-based adsorbent layers 6, 6a, 6b, 6c: raw material gas supply channels 7, 7a, 7b, 7c: treatment Gas discharge channel A: Hydrogen-containing gas (source gas)
B: High purity hydrogen gas (product hydrogen gas)
C: Cleaning gas D: Exhaust gas

Claims (3)

Adsorbent bed provided by laminating three or more adsorption towers and a carbon-based adsorbent layer for adsorbing CO ₂ in the respective adsorption towers of the three or more adsorption towers. High-purity hydrogen gas is obtained by adsorbing and removing unnecessary gas including CO gas from the hydrogen-containing gas by supplying a hydrogen-containing gas from at least the CO adsorbent layer side of each adsorption tower into the adsorption tower. A high-purity hydrogen comprising: a step of producing; and a step of desorbing the unnecessary gas adsorbed on the adsorbent bed by reducing the inside of the adsorption tower to less than atmospheric pressure from the CO adsorbent layer side of each adsorption tower A method for operating a PSA device for gas production,
In the PSA apparatus, all the adsorption towers in each of the adsorption towers are at atmospheric pressure or higher, and at least one of the adsorption towers is in the state of the adsorption pressure of the unnecessary gas from the hydrogen-containing gas. A method for operating a PSA apparatus for producing high-purity hydrogen gas, characterized in that the operation is stopped.   The CO adsorbent is a material in which copper (I) halide and / or copper (II) halide is supported on one or more carriers selected from the group consisting of silica, alumina, and polystyrene resin, or The operation method of the PSA apparatus for high-purity hydrogen gas production according to claim 1, wherein the adsorbent is obtained by reducing this material.   Before all the adsorption towers in each of the adsorption towers are at atmospheric pressure or higher and at least one of the adsorption towers is stopped from the hydrogen-containing gas at the adsorption pressure of the unnecessary gas. Further, the supply of the hydrogen-containing gas into the adsorption tower is stopped, and the adsorbent bed is regenerated while supplying a cleaning gas from the carbon-based adsorbent layer side of each adsorption tower. Or the operating method of the PSA apparatus for high-purity hydrogen gas production of 2.

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