JP2002355520A - Flow rate control pressurization method for four tower- type pressure-swing adsorption equipment for purifying hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the pressure to a target value of the pressure in pressurization process of each adsorption tower and suppress the fluctuation of the amount of product hydrogen without depending on factors, such as the temperature of the outside air environment in wintertime, summertime, daytime or nighttime in a four tower-type pressure-swing adsorption equipment for purifying hydrogen. SOLUTION: A flow rate control pressurization method for the four-tower-type pressure-swing adsorption apparatus for purifying hydrogen is characterized in that, by monitoring as needed the pressure in the adsorption tower in a hydrogen pressurizing process while controlling the flow rate of pressurization hydrogen according to the preset value of the flow rate of hydrogen, and correcting little by little the preset value of the flow rate of hydrogen when the pressure in the adsorption tower is increased to a predetermined adsorption pressure while using a portion of the product hydrogen, the pressure is increased to the predetermined pressure and the fluctuation of the amount of the product hydrogen can be suppressed without depending on the factors such as the temperature of the outside air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the flow rate of hydrogen gas for pressurizing in a pressurizing step in a four-column pressure swing adsorption apparatus for hydrogen purification.

[0002]

2. Description of the Related Art Hydrogen is a basic raw material used for adding hydrogen to unsaturated bonds, for oxyhydrogen flames, and for various other uses, and is also used as a fuel for fuel cells. Industrial methods for producing hydrogen include a steam reforming method and a partial combustion method for hydrocarbon gas. In the steam reforming method, a reformer is used, and a hydrocarbon gas is converted into a reformed gas by a catalytic reaction. The obtained reformed gas contains by-products such as CO and CO ₂ , surplus H ₂ O, and unreformed hydrocarbons, in addition to hydrogen as a main component. Therefore, if the reformed gas is used as it is in a fuel cell, for example, the cell performance will be impaired.

[0003] For example, among fuel cells, CO in hydrogen gas used in a phosphoric acid fuel cell (PAFC) is 1% (capacity%, the same applies hereinafter), and in a polymer electrolyte fuel cell (PEFC), 100 ppm (capacity ppm). Is the limit, and when these are exceeded, the battery performance is remarkably deteriorated. Therefore, it is necessary to purify the reformed gas before introducing it into the fuel cell and to remove those by-products. The hydrogen for adding hydrogen to the unsaturated bond or for the oxyhydrogen flame is usually used in a cylinder, and its purity is 5N (99.999%).
The above is required.

As one of the hydrogen purification methods for obtaining such high-purity hydrogen, a pressure swing adsorption method (PSA method: Pr
essure Swing Adsorption Method). In the PSA method, impurities in a hydrogen-containing gas, for example, a reformed gas generated in a reformer and passed through a CO converter are adsorbed and separated in an adsorbent layer under pressure, and the adsorbed impurities are reduced by reducing the pressure to about normal pressure. Desorb.

[0005] Fig. 1 shows each adsorption tower A in a four-column pressure swing adsorption apparatus for hydrogen purification which is premised in the present invention.
FIG. 4 is a diagram showing an arrangement relationship of a pipe (line), each valve, an off-gas storage tank (off-gas tank), and the like. FIG.
Adsorption in 4-column pressure swing adsorption apparatus as shown in, equalization depressurization pressure equalization holding, vacuum, blowdown, purge, each step of the equalization repressurization, H ₂ boosted (boosted by hydrogen) are repeated, blown Off gas is generated in the down and purge steps.

FIG. 2 is a diagram schematically showing the process flow and operation sequence of each adsorption tower in the four-column pressure swing adsorption apparatus for hydrogen purification shown in FIG. FIG. 2 also shows a pressure change in each adsorption tower as each process proceeds. A raw gas, that is, a reformed gas obtained from a steam reformer (combustion unit + reforming unit) for reforming hydrocarbons through a CO converter is supplied to a tower A, where H ₂ O, CO ₂ , CO ,
The adsorption of impurities such as CH ₄ is performed, and the non-adsorbed hydrogen becomes purified hydrogen (product hydrogen).

[0007] Meanwhile, in the B tower purge step is carried out from the blowdown pressure equalization holding the equalization depressurization is C tower, decompression steps subsequent thereto are performed, H ₂ from the equalization repressurization in D column
The step of increasing the pressure (pressure increase with hydrogen) is performed. The supply of the reformed gas is performed before the impurities are saturated in the tower A and break through.
Automatically switched to tower D. At this point, A tower vacuum holding the equalization depressurization is switched to the pressure reduction step subsequent thereto, B column is switched from the equalization repressurization to H ₂ boosting step, C column from blowdown to purge step The D tower is switched to the adsorption step. Thereafter, these steps are automatically and sequentially switched as shown in FIG. 2 and are repeatedly and continuously operated.

During that time, off-gas generated in the blow-down step and the purge step is sent to the off-gas storage tank T. In these steps, off-gas during the blow-down step was generated in a step of depressurizing and adsorbing impurities adsorbed under pressure to about normal pressure and desorbed, and stored in an off-gas storage tank via an off-gas conduit (off-gas line). Then, it is supplied to the burner of the reformer for hydrogen production.

[0009]

As described above, the four-column pressure swing adsorption apparatus for hydrogen purification employs adsorption, pressure reduction, and pressure reduction.
Equalization hold, decompression, blowdown, purge, equalization increase, H
_The operation is performed in a cycle of ₂ pressure increase (pressure increase by hydrogen). The H ₂ pressurization utilizes a part of the product hydrogen to increase the pressure of the adsorption tower in the water H ₂ pressurization step to a predetermined adsorption pressure.

In the conventional four-column pressure swing adsorption apparatus for hydrogen purification, the pressure is increased by the following methods (1) and (2). (1) A flow rate control method, that is, a method in which the flow rate set value is adjusted so that the flow rate of the hydrogen gas for pressurization is constant and the pressure of the adsorption tower can be raised to a predetermined pressure within the pressurization step time. According to this method, the stability of the product hydrogen flow rate is good, but there are cases where the predetermined pressure is not reached due to the influence of the outside air temperature. (2) A pressure control method, that is, a method in which the valve opening is adjusted so that the pressure of the adsorption tower reaches a predetermined pressure within the time of the pressure increasing step. According to this method, the pressure can always reach the predetermined pressure without being affected by the influence of the outside air temperature or the like, but the flow rate of the hydrogen gas for pressurization changes, so that the product hydrogen amount changes.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem in a four-column pressure swing adsorption apparatus for hydrogen purification, and monitors the pressure of the adsorption tower as needed while controlling the flow rate of hydrogen gas for pressurization. Then, by correcting the flow rate set value in minute increments, it is possible to reach the boost target pressure without being influenced by factors such as the outside air temperature,
It is an object of the present invention to provide a method for controlling a pressure increase flow rate of a four-column pressure swing adsorption apparatus for hydrogen purification that can also suppress fluctuations in a product hydrogen flow rate.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a hydrogen purification device for hydrogen purification.
A step-up flow rate control method of a tower type pressure swing adsorption apparatus, wherein when increasing the pressure of an adsorption tower to a predetermined adsorption pressure using a part of product hydrogen, while controlling the pressurized hydrogen flow rate based on a hydrogen flow rate set value, The pressure in the adsorption tower in the hydrogen pressurization step is monitored as needed, and the set value of the hydrogen flow rate is corrected in minute steps so that the target pressure can be reached without being affected by factors such as the outside air temperature, and the product hydrogen This is a method for controlling a pressure increase flow rate of a four-column pressure swing adsorption device for hydrogen purification, characterized by suppressing a change in the amount.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a 4-column pressure swing adsorption device for hydrogen purification, adsorption, equalization depressurization pressure equalization holding, vacuum, blowdown, purge, by equalization repressurization, H ₂ booster (hydrogen Operation), and at this time,
In the H ₂ pressurization step, it is assumed that a part of the product hydrogen is used and the adsorption tower in the H ₂ pressurization step is pressurized to a predetermined adsorption pressure, that is, the adsorption tower which enters the adsorption step in the next step is increased to the adsorption pressure. .

Further, the present invention provides a four-column pressure swing adsorption apparatus for hydrogen purification, wherein a part of a product hydrogen is used to set the adsorption tower at a predetermined adsorption pressure, that is, in the adsorption tower which enters the adsorption step in the next step. When the pressure is increased to the adsorption pressure,
While controlling the pressurized hydrogen flow rate based on the hydrogen flow rate set value, the pressure in the adsorption tower is monitored as needed, and the hydrogen flow rate set value is corrected in minute steps. This makes it possible to reach the boost target pressure without being influenced by factors such as the outside air temperature, to prevent a case where the target boost pressure does not reach due to a temperature difference in summer, winter or day and night, and to prevent fluctuations in the product hydrogen amount. Can be suppressed.

With respect to this point, in the conventional (1) flow control method, there are cases where the predetermined pressure is not reached due to the influence of the outside air temperature or the like, and in the (2) pressure control method,
Since the flow rate of the pressurizing hydrogen gas fluctuates, the amount of product hydrogen fluctuates. According to the present invention, these problems can be solved simultaneously, that is, all at once.

FIG. 3 shows H in the adsorption tower according to the present invention.
₂ is a diagram showing a flow of boosting the flow control from the start of the boost. For the adsorption tower, set the expected pressure of the adsorption tower with respect to the progress time of the H ₂ pressurization based on the preliminary experiments or results in the pressurization step and input it to the control mechanism, and input the corresponding purified hydrogen flow rate as the hydrogen flow set value to the control mechanism Keep it.
This set value corresponds to the flow rate of the required purified hydrogen corresponding to the expected pressure of the adsorption tower, and the purified hydrogen flow rate is determined by a line branched from the purified hydrogen (product hydrogen) line (a part of the product hydrogen is branched off). This corresponds to the opening of a valve (in FIG. 1, referred to as a valve W) provided in the pressure increasing device.

FIG. 4 is a diagram showing an example of the expected pressure of the adsorption tower with respect to the progress time of the H ₂ pressure increase set based on the preliminary experiment. The “adsorption tower pressure” with respect to “H ₂ pressure increase progress time / pressure increase step set time (%)” in the example in FIG.
This relationship may be curved or the like depending on factors such as the outside air temperature. In the present invention, such an expected pressure in the adsorption tower and the hydrogen flow rate corresponding thereto are input to the control mechanism as a hydrogen flow rate set value. A control computer is preferably used as the control mechanism. The control computer is a CPU, a control program storage memory,
It consists of control data storage memory, timer, etc.
A well-known control computer can be used.

[0018] switched in H ₂ boosting step, measuring the actual pressure in the adsorption tower that started with H ₂ boosting. In FIG. 1 and FIG. 2, the D tower in steps 2 and 3 corresponds to the H ₂ pressure increasing step, but the actual pressure in the adsorption tower D is measured by the pressure gauge PD. The control mechanism compares the measured actual pressure in the adsorption tower with the expected pressure in the adsorption tower, and based on the result, corrects the hydrogen flow rate set value in minute increments. Based on this, the valve opening is corrected in minute increments.

That is, when the actual pressure is equal to or greater than the expected pressure in the adsorption tower, the hydrogen flow set value is corrected by minute small steps, and the valve opening is controlled by a negative correction correspondingly. In FIG. 1, the opening degree of the valve W is controlled to be narrowed in small increments in accordance with the correction of the set value (in FIG. 3, "set value-correction value" is described). Conversely, when the actual pressure ≦ the expected pressure in the adsorption tower, the hydrogen flow set value is corrected by a small positive step, and the valve opening is controlled by a positive correction in response to the correction. In FIG. 1, the opening degree of the valve W is controlled to be increased in small increments according to the correction of the set value (in FIG. 3, "set value + correction value" is described).

According to the present invention, as described above, when the pressure of the adsorption tower is increased by the product hydrogen in each step, the pressure increasing step can always be set to the ideal state, whereby the summer and winter, or It is possible to prevent a case where the target pressure increase pressure is not reached due to a temperature difference or the like due to day and night, and to suppress a fluctuation in the product hydrogen amount. In addition, the pressurized flow control method of the present invention is not limited to the four-column type, but can be applied to a pressure swing adsorption device for hydrogen purification of three or more columns.

In this regard, Japanese Patent Application Laid-Open No. 3-131317 discloses that
A technology for increasing the pressure of an adsorption tower by using a part of product hydrogen has been proposed. However, in this technology, the pressure of the adsorption tower is always read and converted to an electric signal, the pressure of the purified gas pipeline is always read and converted to an electric signal, and the temperature in the adsorption state is read from the pre-treatment gas temperature to read the electric signal. Many means are required, such as converting to a signal. On the other hand, in the present invention, the pressure of the adsorption tower in the step of increasing the pressure is monitored as needed, and the opening degree of the valve is corrected in small increments.
It is possible to reach the target pressure to be raised without being influenced by factors such as the outside air temperature and to suppress the fluctuation of the product hydrogen amount.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. In this embodiment, the apparatus shown in FIG. 1 was used. Activated carbon as a mixed bed in each of the adsorption towers A, B, C, D;
Zeolite was charged.

As a raw material gas, a reformed gas obtained from a reformer for steam reforming city gas (desulfurized) through a CO converter was used. The reformer generally includes a heating section having a burner and a reforming section. Heat (ΔH) from the heating section is supplied to the reforming section, and the raw material gas is converted into a reformed gas by a contact reaction in the reforming section. In FIG. 1, T is an off-gas storage tank, K is an air conduit for burner combustion, and F is a burner fuel gas conduit. If only off-gas is insufficient as burner fuel, city gas or the like is appropriately supplemented and supplemented. PA to PD are pressure gauges of each column A to D, respectively. In addition, CO shown in FIG.
The description of the transformer and the gas cooler is omitted.

The reformed gas is mainly composed of hydrogen.
₄ , CO ₂ , N ₂ , CO and the like. These gases other than hydrogen are gases that are adsorbed and removed by the adsorption tower, and the supply temperature of the reformed gas to the adsorption tower is about 20 to 40 ° C. Since the temperature of the reformed gas passing through the CO converter is higher than that, the gas is cooled to such a temperature by a gas cooler,
Adjusted and supplied to the adsorption tower.

The operation time of each step of the four-column pressure swing adsorption apparatus for hydrogen purification targeted in the present invention is as follows.
Step 1 is 5 to 60 seconds, preferably 20 to 30 seconds, Step 2 is 5 to 60 seconds, preferably 10 to 20 seconds, Step 3 is 110 to 300 seconds, preferably 120 to 190
Range of seconds. Therefore, the adsorption time in steps 1 to 3 is set in the range of 120 to 420 seconds, preferably 150 to 240 seconds.

In this embodiment, step 1 is 25 steps.
Second, step 2 was 15 seconds, and step 3 was 160 seconds. Therefore, the adsorption time is 200 seconds. Step 4
Steps 6 to 6, 6 to 9 and 10 to 12 are the same as steps 1 to 3, respectively. Steps 1 to 3, Steps 4 to
6, steps 7 to 9 and steps 10 to 12 are subcycles, and steps 1 to 12 constitute one cycle.

The operating pressure is 0.7 MPaG at the time of the adsorption step (the same until the end of the adsorption step), 0.6 MPaG at the time of pressure equalization, pressure reduction hold and pressure reduction end, and 0.02 at the end of blowdown.
MpaG, 0.22 MPaG at the end of purge, and 0.68 MPa at the end of pressure increase. The adsorption pressure in the adsorption step is controlled by a control valve arranged in the purified hydrogen line, but is not shown. In the following operation, the valve V is open through steps 1 to 12. In the following, blowdown (step) is abbreviated as blow (step) as appropriate.

<Step 1> A tower = adsorption, B tower = blowing, C tower = equalizing pressure reducing, D tower = equalizing pressure increasing valves A1, A2 are opened, and the reformed gas is supplied to the A tower to perform the adsorption operation. Was carried out. In the meantime, the blowing step was performed in the tower B, the equalizing pressure reducing step was performed in the tower C, and the equalizing pressure increasing step was performed in the tower D. As for the other valves, the valves B5, C4, and D3 were opened, and the opening degrees of the valves W, X, Y, and Z were kept constant. Other valves are closed.

<Step 2> A tower = adsorption, B tower = blowing, C tower = reduced pressure, D tower = H ₂ boosting valve Same as step 1 except that the valve C4 and the valve X were closed. The raw gas was supplied to the tower A to perform the adsorption operation. During that time, a blowing step was performed in the tower B, a pressure reduction step was performed in the tower C, and a pressure equalizing step was performed in the tower D. Here, the valve W is provided on a line branched from the product hydrogen line, and its opening degree is adjusted at the end of <Step 3> by adding <Step 3> to <Step 2> as shown in FIG. At 0.68 MPa. That is, since Step 2 is 15 seconds and Step 3 is 160 seconds, the total of <Step 2> and <Step 3> is 17 seconds.
5 seconds (= step-up step setting time). During this time, the pressure in the tower D was set so as to be 0.68 MPa. During operation,
The pressure inside the tower D was measured by a pressure gauge PD (measurement of the actual pressure inside the adsorption tower in FIG. 3), and monitored as needed.

<Step 3> The reformed gas was continuously supplied in the same manner as in Step 2 except that the tower A was adsorbed, the tower B was purged, the tower C was depressurized, and the tower D was H ₂ booster valves B4 and C4 were opened. The mixture was supplied to the tower A to perform an adsorption operation. Meanwhile, the purging step in the tower B, the depressurizing step in the tower C,
In the tower D, an H ₂ pressure increasing step was performed.

During a period between <Step 2> and <Step 3>, the measured value of the actual pressure in the adsorption tower was compared with a preset expected pressure in the adsorption tower by the control mechanism. It was observed that pressure ≧. Therefore, based on the difference, the set value is negatively corrected by the control mechanism, and the opening degree of the valve W is reduced in small increments, so that the pressure in the D tower is 0.68 MPa at the end of <Step 3>. And could be. This means that if this control was not performed, the pressure in the D column exceeded 0.68 MPa, and the D column could not smoothly transition to the adsorption step following the pressure increasing step. I do.

<Step 4> A tower = equalization pressure reduction, B tower = equalization pressure increase, C tower = blowing, D tower = adsorption valves D1 and D2 are opened, and reformed gas is supplied to D tower to perform adsorption operation. Was carried out. During that time, the equalizing pressure reducing step was performed in the tower A, the equalizing pressure increasing step was performed in the tower B, and the blowing step was performed in the tower C. With respect to the other valves, the valves A4, B3, and C5 were opened, and the opening degrees of the valves W, X, Y, and Z were kept constant. Other valves are closed.

<Step 5> Tower A = retained pressure, Tower B = H
₍₂₎ Pressurization, C tower = blow, D tower = adsorption In the same manner as in step 4 except that the valve A4 and the valve X were closed, the reforming gas was continuously supplied to the D tower to perform the adsorption operation. In the meantime, the tower A performed the reduced pressure holding step, the tower B performed the H ₂ pressure increasing step, and the tower C performed the blowing step. Here, as shown in FIG. 4, the opening degree of the valve W was set to be 0.68 MPa at the end of <Step 6>. That is, the total of <Step 5> and <Step 6> is 175 seconds (step-up step set time), during which D
The column pressure was set so as to be 0.68 MPa. During the operation, the pressure in the tower D was measured by the pressure gauge PD and monitored as needed.

<Step 6> A tower = decompression, B tower = H ₂ pressure increase, C tower = purge, D tower = adsorption Same as step 5, except that A4 and C4 were opened.
Subsequently, the reforming gas was supplied to the tower D to perform an adsorption operation.
In the meantime, the pressure reduction step is performed in the tower A, the H ₂ pressure increase step is performed in the tower B,
During the operation, the pressure in the tower B was measured by a pressure gauge PB and monitored as needed.

During the period from <Step 5> to <Step 6>, the measured value of the actual pressure in the adsorption tower was compared with the preset expected pressure in the adsorption tower by the control mechanism. It was observed that pressure ≧. Therefore, based on the difference, the control mechanism performs a negative correction on the set value to reduce the opening degree of the valve W in small steps, thereby obtaining B at the end of <Step 6>.
The pressure in the tower could be 0.68 MPa, and the product hydrogen amount could be stabilized.

<Step 7> A tower = blow, B tower = adsorption, C tower = equalizing pressure increase, D tower = equalizing pressure reducing valves B1 and B2 are opened, and reforming gas is supplied to B tower to perform adsorption operation. Was carried out. During that time, the blowing step was performed in the tower A, the equalizing pressure increasing step in the tower C, and the equalizing pressure reducing step in the tower D. With respect to the other valves, A5, C3, and D4 are opened, and valves W,
The opening degrees of the valve X, the valve Y, and the valve Z were made constant. Other valves are closed.

<Step 8> A tower = blow, B tower = adsorption, C tower = H ₂ boost, D tower = depressurization holding Same as step 7, except that valve D4 and valve X were closed. The raw gas was supplied to the tower B to perform the adsorption operation. In the meantime, the blowing process is performed in the tower A, and the blowing process is performed in the tower C.
_{(2) The} pressure raising step, and the reduced pressure holding step were performed in the tower D. Here, the opening degree of the valve W was set to 0.68 MPa at the end of <Step 9> as shown in FIG. During the operation, the pressure in the tower C was measured by a pressure gauge PC and monitored as needed.

<Step 9> A tower = purge, B tower = adsorption, C tower = H ₂ pressure increase, D tower = pressure reduction Same as step 8 except that A4 and D4 were opened.
Subsequently, the reforming gas was supplied to the tower B to perform an adsorption operation.
Meanwhile, the tower A has a purge step, the tower C has a H ₂ pressure increasing step,
In the tower D, a pressure reduction step was performed, and the pressure in the tower C was measured by a pressure gauge PC and monitored as needed.

During the period from <Step 8> to <Step 9>, the measured value of the actual pressure in the adsorption tower was compared with the preset expected pressure in the adsorption tower by the control mechanism. It was observed that pressure ≧. Therefore, based on the difference, the set value is negatively corrected by the control mechanism, and the opening degree of the valve W is reduced in small steps, so that C at the end of <Step 9> is reduced.
The pressure in the tower could be 0.68 MPa, and the product hydrogen amount could be stabilized.

<Step 10> Tower A = equalizing pressure increase, Tower B =
Equalization pressure reduction, C tower = adsorption, D tower = blow valves C1 and C2 were opened, and the reforming gas was supplied to the C tower to perform the adsorption operation. In the meantime, the equalizing pressure increasing step was performed in the tower A, the equalizing pressure reducing step was performed in the tower B, and the blowing step was performed in the tower D. With respect to the other valves, A3, B4, and D5 are opened, and valves W,
The opening degrees of the valve X, the valve Y, and the valve Z were made constant. Other valves are closed.

<Step 11> Tower A = H ₂ boost, Tower B =
Step 10 except that the pressure reduction was maintained, the tower C was adsorbed, and the tower D was blow valve B4 and valve X were closed.
In the same manner as described above, the reforming gas was continuously supplied to the column C to perform the adsorption operation. In the meantime, the tower A performed the H ₂ pressure increasing step, the tower B performed the reduced pressure holding step, and the tower D performed the blowing step. Here, as shown in FIG. 4, as shown in FIG. 4, the pressure in the tower A becomes 0.68M in 175 seconds including the following <Step 12>.
Pa was set. During the operation, the pressure in the tower A was measured by the pressure gauge PA and monitored as needed.

<Step 12> Tower A = H ₂ boost, Tower B =
Depressurization, C tower = adsorption, D tower = purge Except that B4 and D4 were opened, the adsorption operation was performed by continuously supplying the reformed gas to the C tower in the same manner as in step 11. In the meantime, the H ₂ pressure increasing step was performed in the tower A, the pressure reducing step was performed in the tower B, and the purging step was performed in the tower D.

During the period from <Step 11> to <Step 12>, the measured value of the actual pressure in the adsorption tower was compared with the preset expected pressure in the adsorption tower by the control mechanism. It was observed that pressure ≤. Therefore, based on the difference, a positive correction is made to the set value by the control mechanism, and the opening degree of the valve W is increased in small increments, so that the pressure in the tower A at the end of <Step 12> is reduced to 0.1. 68 MPa, and the product hydrogen amount could be stabilized. This means that if this control was not performed, the pressure in the tower A would be 0.6
This means that the pressure in the column A did not reach the adsorption pressure within a predetermined time because the pressure was lower than 8 MPa, and it was not possible to smoothly shift to the adsorption step following the pressure increasing step.

[0044]

According to the present invention, in the four-column pressure swing adsorption apparatus for hydrogen purification, the pressure rising step of each adsorption tower can be performed without being affected by factors such as the outside air temperature in summer, winter, or day and night. And the fluctuation of the product hydrogen flow rate can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing the arrangement of adsorption towers A to D, piping, valves, off-gas storage tanks, and the like in a four-column PSA apparatus for hydrogen purification.

FIG. 2 is a diagram schematically showing a process flow and an operation sequence of each adsorption tower in the four-column PSA apparatus for hydrogen purification shown in FIG.

FIG. 3 is a diagram showing a flow of pressure increase flow control from the start of H ₂ pressure increase in the adsorption tower according to the present invention.

FIG. 4 is a diagram showing an example of an expected pressure of an adsorption tower with respect to a progress time of H ₂ pressure increase set based on a preliminary experiment.

[Explanation of symbols]

 A to D adsorption tower T off-gas storage tank F burner fuel gas conduit K burner combustion air conduit PA to PD Pressure gauge for measuring actual pressure in adsorption towers A to D

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroki Furuta 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Co., Ltd. (72) Inventor Tohru Takahashi 1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas Inside (72) Inventor Kenichi Nakamura 3-7-1 Nishi Shinjuku, Shinjuku-ku, Tokyo Shinjuku Park Tower 10th floor Tokyo Gas Chemical Co., Ltd. Inside (72) Inventor Koji Aida 3-7-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Shinjuku Park Tower 10th Floor Tokyo Gas Chemical Co., Ltd. Person Kumiko Moriguchi 1-13-501, Arima 1-chome, Miyamae-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Hideki Miyajima 5-2-10 F-Terao, Tsurumi-ku, Yokohama City, Kanagawa Prefecture None (reference) 4D012 CA07 CB16 CD07 CE01 CE02 CE03 CF02 CF03 CF04 CG01 CH10 5H027 BA01 BA16 BA17 KK01 KK21 MM01

Claims (2)

[Claims] 1. A method for controlling a pressure increase flow rate of a four-column pressure swing adsorption apparatus for hydrogen purification, wherein a pressure of an adsorption tower is increased to a predetermined adsorption pressure using a part of product hydrogen based on a set value of a hydrogen flow rate. While controlling the pressurized hydrogen flow rate, the pressure in the adsorption tower in the hydrogen pressurization step is monitored as needed, and the set value of the hydrogen flow rate is corrected in minute steps, thereby increasing the pressure regardless of factors such as the outside air temperature. To reach the target pressure, and
A method for controlling a pressurized flow rate of a four-tower pressure swing adsorption apparatus for hydrogen purification, characterized by suppressing fluctuations in a product hydrogen amount. 2. A method for controlling the pressure increase flow rate of the four-column pressure swing adsorption apparatus for hydrogen purification, comprising the steps of: adsorbing, equalizing and reducing, equalizing holding, reducing, blowing down, purging, equalizing and increasing pressure in each of the four columns. The method according to claim 1, wherein the step of increasing the pressure of the hydrogen is a step of repeating the step of increasing the pressure of the hydrogen in the step of increasing the pressure of the hydrogen.