JPH072025Y2 - Pressure swing adsorption device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a multi-unit type pressure swing adsorption device (PSA device, pressure swing) in which a plurality of adsorption units composed of a plurality of adsorption towers are arranged in parallel.
adsorptionapparatus), in particular, a multi-unit pressure swing adsorption device used to separate air.

[0002]

2. Description of the Related Art Up to now, it has been known to use a PSA device to adsorb and separate a mixed gas composed of a plurality of gas components into respective constituent gas components. There are a two-column type in which the towers form one unit, and a four-column type in which four adsorption columns are connected in parallel to form one unit.

However, all of these PSA devices are of the one-unit type, and
When designing the device, for example, by performing a performance test experiment using a small N ₂ -PSA device, the optimum superficial velocity, Air /
N _2, product N ₂ amount / adsorbent loading, packing height / column diameter, etc. calculated in advance the amount of air / Todan area, by using these values directly, the product N ₂ given from the demand end The required amount of raw material air was calculated according to the amount. therefore,
The diameter of the adsorption tower (tower diameter) is based on the empty column cross-sectional area (empty column cross-sectional area per tower) obtained by dividing the raw material air volume calculated in this way by the previously calculated empty column velocity. Had been decided.
Therefore, the larger the amount of raw material air, the larger the column diameter required, and it was difficult to downsize the entire apparatus.

Further, in the case of the conventional small-sized PSA apparatus, since the tower diameter of the adsorption tower is small, a relatively uniform fluidized state can be obtained in the adsorption tower, but the adsorption tower is used to separate a large amount of raw material air. The PSA device having a large diameter has the following problems. First, the first problem is that since the tower diameter of the adsorption tower is large, L / D (L: adsorbent filling height, D:
This is because the value of (inner diameter of adsorption column) becomes small, the gas flow state in the adsorption column tends to be non-uniform, and the performance such as the product purity is deteriorated. L / D from the experience rule so far
In the case of a two-column PSA device satisfying the formula of ≦ 3, the raw material air has a non-uniform flow in the adsorption process, and the purge gas having a relatively small amount of gas does not flow uniformly in the desorption process. It is known that a channeling phenomenon of fluid flow occurs. As a result, such a two-tower type P
In the SA device, desorption of the adsorbed oxygen component becomes insufficient, sufficient purge regeneration is not performed, and the oxygen component cannot be sufficiently adsorbed and separated by the adsorbent (eg, molecular sieve, carbon) in the adsorbing process of the next process. As a result, the separation efficiency decreases.

Next, the second problem in the conventional small-sized PSA apparatus is the performance deterioration due to the pressure fluctuation when switching the adsorption tower. That is, as shown in (a) to (c) of FIG. 5, in the conventional two-tower N ₂ -PSA apparatus, when the adsorption tower is switched, the A tower, which has been in the adsorption step until now, becomes the desorption step. The column B, which has been in the desorption process until now, becomes the adsorption process (see (a) and (c) of FIG. 5). At this time, in general, in order to improve the product yield, the adsorption is performed in the adsorption process-equalization process-desorption process in the tower A, and in the desorption process-equalization process-adsorption process in the tower B as opposed to the adsorption process in the tower A. A pressure equalizing step is provided between the step and the desorption step (see FIG. 5B), and in this pressure equalizing step, the nitrogen component remaining in the adsorption tower is transferred to another tower and recovered.

Therefore, such a conventional two-tower type N ₂ -P
In the pressure equalization step of the SA device, product nitrogen could not be taken out from the adsorption tower, large pressure fluctuations occurred when switching the adsorption tower, and from the measurement example of the concentration distribution in the adsorption tower in the adsorption step shown in FIG. As can be seen, there is a problem that the product nitrogen concentration fluctuates greatly due to pressure fluctuations.

In addition, in the case of medium to large N ₂ -PSA devices and O ₂ -PSA devices, when the capacity of the adsorption tower becomes large, the installation area of the entire device (or the size of the adsorption unit in the device, If the diameter of the adsorption tower becomes large and becomes larger than the width of the vehicle (for example, the width of the bed of a truck), it becomes difficult to transport the assembled assembly in the factory. And in the case of such a large PSA device,
There is also the problem that the assembly will have to be carried out on-site, and the period required to assemble the device will become longer.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the conventional PSA apparatus, can keep the gas flow state in the adsorption tower even, and can prevent the pressure when switching the adsorption tower. It is an object of the present invention to provide a pressure swing adsorption device which has a small fluctuation and is capable of separating a large amount of mixed gas with good performance.

The inventor of the present invention has a structure in which a conventional adsorption unit composed of a plurality of adsorption columns is arranged in parallel to form a multiple unit structure, and the flow rate of the mixed gas flowing into each adsorption unit is adjustable by a flow divider and a valve. By keeping the gas flow state in the adsorption tower uniform by shifting the adsorption tower switching time in the adsorption unit by the sequencer, the pressure fluctuation when switching the adsorption tower is reduced and the separation performance is improved. Was successful. In addition, even if the capacity of the product gas holder where the gas separated in each adsorption unit is finally collected is small, by installing a confluencer and a valve before being sent to the product gas holder, It was found that the mixed gas can be separated in a state where the gas flow state is uniform and the pressure fluctuation when switching the adsorption tower is small.

[0010]

The pressure swing adsorption device of the present invention is a pressure swing adsorption device used for separating a mixed gas composed of a plurality of gas components into respective constituent gas components, and two or more adsorption towers. Are connected in parallel to form one adsorption unit, and two or more of the adsorption units are connected in parallel. On the mixed gas inflow side of each adsorption unit, the mixed gas is fed to each adsorption tower. A flow divider capable of dividing the flow is provided, and a flow dividing gas control valve capable of adjusting the flow rate of the mixed gas sent to each adsorption unit is provided between the flow divider and the adsorption unit. That is, the separation gas outflow side of each adsorption unit is connected to a separation gas surge tank for each adsorption unit. That it is connected with the scan holder,
Also, the adsorption tower switching time in the adsorption unit is controlled so as to shift for each adsorption unit.

The present invention also provides the above-mentioned adsorption device,
Between each separation gas surge tank and the product gas holder, there is a combiner that can combine the separated gases, and between this combiner and each separation gas surge tank, there is a combiner. It is also characterized in that a merged gas control valve capable of adjusting the flow rate of the separated gas to be sent is provided respectively.

First, FIG. 1 shows a block diagram of an N ₂ -PSA apparatus as an example of the PSA apparatus of the present invention, but the present invention is not limited to this. As shown in FIG. 1, according to the present invention, two or more adsorption units 3 formed by connecting two or more adsorption columns in parallel are connected in parallel, which is a multi-tower multiple unit type. The point is greatly different from the conventional one (the PSA apparatus of the present invention shown in FIG. 1 has two adsorption towers as one unit).
It is a unit type). Therefore, compared to the conventional one, it is possible to reduce the amount of mixed gas (air) flowing into one adsorption tower, and it is possible to reduce the tower diameter.
Since the L / D value is easily set to 3 or more, it is possible to prevent one of the conventional problems, that is, the nonuniform flow distribution of the mixed gas in the adsorption tower. The simplest one adsorption unit 3 in the present invention is one composed of two towers (A tower and B tower) as shown in FIG. 1, but may be three or more towers. The inside of the adsorption towers A and B shown in FIG. 1 is filled with a filler according to the gas components constituting the mixed gas, and as the filler, various adsorbents that have been commercially available so far are used. (For example, molecular sieve, carbon, etc.) can be widely used.

Further, in the PSA apparatus of the present invention, the gas in each adsorption unit 3 can be divided so that the nonuniform flow distribution of the mixed gas can be eliminated and the mixed gas of the raw materials can be evenly divided into each adsorption unit 3. On the inlet side (generally, the inlet of the bottom of each adsorption unit), a flow divider 1 and a flow dividing gas control valve 2 capable of dividing the mixed gas sent to each adsorption tower are provided.

The flow diverter 1 generally has a structure as shown in FIG. 3, and the mixed gas flowing from the mixed gas inlet 9 passes through the inside of the main body of the flow diverter 1 to be mixed. It flows out from the gas outlet 10. The flow divider 1 of FIG. 3 is used when the number of adsorption units is two, but when the number of adsorption units is n, n mixed gas outlets 10 are provided. Should be used. At this time, the inner diameter D of the flow distributor 1 and the inner diameter d of the mixed gas inflow port 9 are divided so that the mixed gas is evenly divided into the adsorption units.
It is preferable that the inner diameter d of the mixed gas outlet 10 satisfies the equation of D ≧ 2d.

On the other hand, each of the split gas control valves 2 is
It is provided between the flow divider 1 and the adsorption unit 3, and this valve can adjust the flow rate of the mixed gas sent to each adsorption unit 3. Generally, the static pressure of fluid, especially gas, in the pipe is determined by the flow resistance, and it is necessary to branch the mixed gas inlet pipe to each unit and equalize the static pressure in all pipes after the branch. In the present invention, the diversion gas control valve 2 provided in the pipe to the flow divider 1 and each adsorption unit 3 is
It acts to equalize the static pressure of the raw material mixed gas (for example, air). A needle valve or a fixed orifice may be used as the split gas control valve 2.

As described above, in the PSA apparatus of the present invention, the mixed gas to be separated is evenly divided into the adsorption units 3 by the flow divider 1 and the dividing gas control valve 2, and the gas concentration distribution in the adsorption tower is made uniform. Therefore, the deterioration of the adsorption separation performance due to the non-uniform flow, which occurs when treating the total amount of air with one adsorption unit as in the conventional case, and the reduction of the product purity in particular does not occur.

The N ₂ -PSA of the present invention shown in FIG. 1 is used.
In the device, the supply amount of the raw material air is measured by the flow meter 8 so that the total amount of the mixed gas (raw material air) supplied to the adsorption unit 3 becomes a predetermined flow rate required for the entire device. Divided gas control valve 2 provided for every 3
The air is introduced into each adsorption unit 3 so as to be evenly divided, and after being adsorbed and separated in the A tower and the B tower, the exhaust gas generated by the separation is exhausted from each adsorption unit 3. It has a structure.

Further, in the PSA apparatus of the present invention, as shown in FIG. 1, the separation gas (nitrogen gas) of each adsorption unit 3 is separated.
The outflow side is connected to the separation gas surge tank 5 for each adsorption unit, and each of the separation gas surge tanks 5 is further connected to one product gas holder 7 having a large capacity as shown in FIG. There is. The separation gas surge tank 5 has a function of averaging the change over time of the product gas concentration as much as possible and sending it to the product gas holder 7, and also a function of reducing the fluctuation of the pressure change. In this way, the product gas separated in each adsorption unit 3 is
It is collected in the product gas holder 7, passed through this product holder 7, and then taken out as a final product.

Further, in another PSA apparatus according to the present invention, as shown in FIG. 2, the separated gas (nitrogen gas) outflow side of each separated gas surge tank 5 can join the separated gases. It is connected to the combiner 4, and the separated gas is sent to the product gas holder 7 via the combiner 4. The merger 4 has a structure similar to that of the flow divider 1 described above. For example, as shown in FIG. 4, the separated gas introduced from each separated gas inlet 12 is inside the main body of the merger 4. Through the separation gas outlet 11.
At this time, the relationship between the inner diameter D of the merger 4 and the inner diameter d of the separation gas inflow port 12 and the inner diameter d of the separation gas outflow port 11 is the same as in the case of the flow divider 1 described above, and the equation of D ≧ 2d It is preferable to satisfy.

Further, in the PSA apparatus of the present invention shown in FIG. 2, between the confluence unit 4 and each separation gas surge tank 5,
Each of the confluent gas control valves 6 is provided, and the flow rate of the separation gas (nitrogen gas) sent to the confluence device 4 is adjusted uniformly by the valves 6, but the confluent gas control valve 6 is not provided. In some cases, the flow rate of the separated gas sent to the combiner 4 can be adjusted evenly by the split gas control valve 2, and the combined gas control valve 6 in the present invention is appropriately provided. In this way, the effect obtained by evenly adjusting the flow rate for each separation gas surge tank 5 is the same as in the case where the mixed gas is evenly divided into the adsorption units 3 by the divided gas control valve 2 described above. As the merged gas control valve 6, the same one as the split gas control valve 2 described above can be used.

In the present invention, the product gas holder 7 determines whether or not it is necessary to provide the flow divider 4, that is, whether or not the PSA device having the configuration shown in FIG. It is determined by the average residence time of the product gas in the above. If this average residence time is 10 sec. Or more, the flow divider 4 may not be provided, and the PSA device having the configuration shown in FIG. 1 can be used. The product gas concentration from the gas surge tank 5 becomes uniform.
However, when the average residence time of the product gas in the product gas holder 7 becomes 10 sec. Or less, the PSA device having the configuration shown in FIG. As described above, according to the present invention, the flow divider 4 is not necessarily provided, and when the flow divider 4 is not provided (when the inner volume of the product gas holder 7 is large), the product gas holder 7 is not provided. Will also have the role of.

Further, the PSA apparatus of the present invention has a structure having a plurality of adsorption units 3, and the adsorption tower switching time in each adsorption unit 3 is controlled so as to be different for each adsorption unit 3. For example, when the adsorption unit 3 is a two-tower type, the adsorption towers (A tower and B tower) are switched for each half cycle time while being shifted for each adsorption unit 3. At the same time, the adsorption tower does not switch at the same time. In the present invention, the adsorption tower switching time is generally controlled so as to be evenly shifted by a sequencer control or the like, and a sequencer is provided. Incidentally, FIG.
The sequencer is not shown in the PSA device of the present invention shown in FIG.

Since the adsorption tower switching time is controlled in this way, the PSA apparatus of the present invention can reduce the pressure fluctuation when the adsorption tower is switched, thereby improving the product purity. On the other hand, in the case of using the conventional 2-tower 1-unit type N ₂ -PSA apparatus, as shown in FIG.
As shown in the concentration distribution curve in the adsorption tower, when the adsorption tower is switched to the adsorption step, the pressure equalization step, the desorption step, or the opposite direction, the fluctuation of the product concentration increases with the pressure fluctuation during the pressure equalization step. There is a problem that the separation performance deteriorates,
The PSA device of the present invention solves such a problem.

In order to reduce the concentration fluctuation when the adsorption tower is switched, it is necessary to reduce the pressure fluctuation in the pressure equalizing step. In this respect, the plurality of adsorption unit types in the present invention have the conventional ones. It is extremely advantageous over the unit type. That is, when the adsorption tower switching times in the plurality of adsorption units connected in parallel are evenly shifted, the pressure fluctuation (concentration fluctuation) can be minimized. For example, the adsorption tower switching time in each unit is 60 seconds. In case of 3 unit type (triple type), 60/3 = 20 sec.
It is controlled so that the adsorption tower of the adsorption unit is switched at intervals of. The pressure fluctuation when using such a 3-unit type PSA apparatus is reduced to about 1/3 of that when using the 1-unit type PSA apparatus.

When performing the adsorption separation of the mixed gas using the PSA device of the present invention, the adsorption tower switching time and the purge amount are preset among the operating conditions of each adsorption unit, especially the conditions affecting the separation performance. It is necessary to adjust the amount of air to be introduced by the diverting gas control valve and the pressure equalization time while operating each adsorption unit.
Then, attach a concentration meter for adjustment to each adsorption unit, adjust the mixed gas input amount to each adsorption unit, whether the raw material air is evenly distributed to each adsorption unit, and whether the product gas is evenly joined. Please drive after confirming.

The PSA device of the present invention is very suitable for separating nitrogen gas and oxygen gas from air, but the present invention is not limited to this, and the adsorbent filled in the adsorption tower is used. Can be used for separating various mixed gases by appropriately selecting.

[0027]

EXAMPLES Example 1: Performance test test by 5-unit type N ₂ -PSA device (a device for separating nitrogen gas as a product from raw air, which is a pressure adsorption and atmospheric desorption system) Filling height 85 cm × Two adsorption towers having an inner diameter of 15 cm were connected in parallel to form one adsorption unit, and five such adsorption units were connected in parallel to form an adsorption separation section. Then, on the gas inflow side of each adsorption unit, as a flow divider capable of diverting the mixed gas sent to each adsorption unit, the structure shown in FIG. 3 (inner diameter D = 3
cm, inner diameter d = 0.4 cm), and a diversion gas control valve (needle valve) that can adjust the flow rate of the mixed gas sent to each adsorption unit between the diversion device and the adsorption unit. Provided.

On the other hand, a separation gas surge tank (capacity 10 liters) is connected to the separation gas discharge side of each adsorption unit, and this separation gas surge tank is further connected to a product gas holder (capacity 40 liters). A pressure swing adsorption device (two towers and five units type) of the present invention having a partial structure similar to that shown in FIG. 1 was manufactured. In this adsorption device, since the product gas holder having a relatively large internal volume also serves as a confluencer, the confluencer is not separately installed. For convenience, the air used in the adsorption separation test is composed of nitrogen and oxygen, and molecular sieve carbon is used as an adsorbent that preferentially adsorbs oxygen, and about 10 kg is used per adsorption tower. did.

Then, to the pressure swing adsorption device, 32 Nm ^{3 of} raw material air compressed to about 7.5 kg / cm ² G by a compressor was introduced per hour, and the branch gas control valve was adjusted to adjust each adsorption unit. The adsorption / separation operation was performed so that the raw material air was evenly divided. At this time, the adsorption tower switching time in each unit was evenly shifted by 15 seconds. The product nitrogen thus separated from each adsorption unit was collected in the product gas holder, and finally the product nitrogen was taken out.

As a result, the above-mentioned 5-unit type N ₂ -P
In the SA device, product nitrogen having a product nitrogen purity of 0.70% O ₂ (the O ₂ concentration of impurities in the product nitrogen was 0.70% O _2
2 ) 10 Nm ³ (about 2.8 liters / hour)
sec.) I was able to collect. Therefore, the average residence time of the product gas in the product gas holder in Example 1 was 40 / 2.8 = about 14 sec.

Example 2: Performance test test using a 5-unit type N ₂ -PSA device (PSA device provided with a confluent device) In the N ₂ -PSA device described in Example 1, the product gas holder has a capacity of 20 liters. Of the structure shown in FIG. 4 (inner diameter D = 3 cm, inner diameter) between the product gas holder and the separated gas surge tank. d = 0.4
cm) was provided. Further, in the pipe connecting the separation gas surge tank and the merger, a combination gas control valve capable of adjusting the flow rate of the separation gas supplied from the separation gas surge tank is provided, respectively, as shown in FIG. The pressure swing adsorption device of the present invention (2
Tower 5 unit type) was manufactured.

Then, in the same manner as in Example 1, raw material air was introduced to separate nitrogen gas as a product. At this time, the flow rate of the product nitrogen sent to the combiner was adjusted by the combined gas control valve so that the pressure was uniform. As a result, by using the above-mentioned 5-unit type N ₂ -PSA apparatus, Example 1
It was possible to collect product nitrogen having the same product nitrogen purity as 10 Nm ³ (about 2.8 liter / sec.) Per hour. Therefore, in this Example 2, the average residence time of the product gas in the product gas holder is 20 / 2.8 = about 7
It was sec.

Example 3: Performance test test by a 5-unit type O ₂ -PSA apparatus (an apparatus for separating oxygen gas as a product from raw material air) In the 5-unit type N ₂ -PSA apparatus described in Example 1, By filling each adsorption tower with about 10 kg of synthetic zeolite 5A as an adsorbent instead of molecular sieve carbon, a 5-unit type O ₂ -P of the present invention
The SA device was manufactured. And about 2.0k by the compressor
The raw material air compressed to g / cm ² G was introduced at 100 Nm ³ per hour to perform adsorption separation operation. As a result, 10 Nm ^{3 of} product oxygen having a product oxygen purity of 94% O ₂ could be collected per hour in the above-mentioned 5 unit type O ₂ -PSA apparatus.

Comparative Example 1 (an example of a conventional N ₂ -PSA apparatus) A 1 unit type N ₂ -PSA apparatus having an adsorption tower having a packing height of 106 cm and a tower inner diameter of 30 cm was used in the same manner as in Example 1 An experiment was conducted to separate nitrogen from the feed air.
As a result, in the case of this PSA device, 1 per hour
35 N per hour to collect 0 Nm ³ of product nitrogen
It is necessary to introduce m ³ of air, and the purity of the obtained product nitrogen is 0.75% O ₂ (the O ₂ concentration of impurities in the product nitrogen is 0.75% O ₂ ) It was found that the purity was lower than in the cases of Example 1 and Example 2.

Comparative Example 2 (an example of a conventional O ₂ -PSA apparatus) A 1 unit type O ₂ -PSA apparatus having an adsorption tower having a packing height of 106 cm and a tower inner diameter of 30 cm was used in the same manner as in Example 3. An experiment was conducted to separate oxygen from the feed air.
As a result, in the case of this PSA device, 1 per hour
115 hours per hour to collect 0 Nm ³ of product oxygen
It was found that it was necessary to introduce Nm ³ air, and the purity of the product oxygen obtained was 93% O ₂ , which was lower than that in the case of Example 3.

[0036]

Effect of the Invention In the PSA apparatus of the present invention, the diameter of the adsorption tower per unit is smaller than that of the conventional 1-unit type PSA apparatus, so that a uniform flow easily occurs in the adsorption tower.
High separation efficiency is obtained, and the product purity does not decrease.
Further, since the column switching time is shifted for each unit, the pressure fluctuation at the time of column switching is small and the separation efficiency is high accordingly. Furthermore, since the adsorption tower volume is small, the purge noise accompanying the tower switching is also small. In addition, as an additional effect, since the adsorption towers are unitized, the device capacity can be easily adjusted in small increments and automation is possible.

The PSA apparatus of the present invention is particularly suitable for separating a large amount of air, and the N ₂ -PSA apparatus that separates air to make nitrogen gas is a seal gas for preventing oxidation and It can be used to provide an explosion-proof seal gas, a small N ₂ -PSA device can be used in place of a nitrogen cylinder, and a medium N ₂ -PSA device can be used in place of liquid nitrogen.

Incidentally, this is not limited to the N ₂ -PSA apparatus, but can also be applied to an O ₂ -PSA apparatus using zeolite as an adsorbent, and air is separated to generate oxygen gas. The product O ₂ -PSA device can be used to supply a raw material gas for ozone generation, and is a small O ₂ -PSA device.
The PSA device is a medium-sized O ₂ -P instead of the oxygen cylinder.
The SA device can be used instead of liquid oxygen.
As described above, the PSA device of the present invention can be used in a very wide range of fields.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a pressure swing adsorption device (two towers and three units type N ₂ -PSA device) of the present invention.

FIG. 2 is a pressure swing adsorption device of the present invention (two towers and three units type N ₂ −
It is a block diagram which shows an example of a (PSA apparatus).

FIG. 3 is a structural diagram showing an example of a flow divider in the pressure swing adsorption device of the present invention.

FIG. 4 is a structural diagram showing an example of a confluencer in the pressure swing adsorption device of the present invention.

FIG. 5: (a) A tower adsorption step in a conventional pressure swing adsorption apparatus (two towers and one unit type N ₂ -PSA apparatus),
It is a figure which shows (b) equalization process and (c) B tower adsorption process.

FIG. 6 is a graph showing changes in the oxygen concentration distribution in the adsorption tower when air is separated using the conventional N ₂ -PSA apparatus shown in FIG.

[Explanation of symbols]

 1 flow divider 2 flow dividing gas control valve 3 adsorption unit 4 flow combiner 5 separation gas surge tank 6 flow mixing gas control valve 7 product gas holder 8 flow meter 9 mixed gas inlet 10 mixed gas outlet 11 separated gas outlet 12 separated gas flow entrance

Claims (2)

[Scope of utility model registration request] 1. A pressure swing adsorption apparatus used for separating a mixed gas composed of a plurality of gas components into respective constituent gas components, wherein two or more adsorption towers are connected in parallel to form one adsorption unit 3. And two or more of the adsorption units 3 are connected in parallel, and on the mixed gas inflow side of each of the adsorption units 3, there is provided a flow divider 1 capable of dividing the mixed gas into each of the adsorption towers. Provided between the flow distributor 1 and the adsorption unit 3 is a diversion gas control valve 2 capable of adjusting the flow rate of the mixed gas sent to each adsorption unit 3, and each adsorption The separation gas outflow side of the unit 3 is connected to the separation gas surge tank 5 for each adsorption unit, and each separation gas surge tank 5 is further connected to the product gas holder 7. And the adsorption tower switching time in the adsorption unit 3 is controlled so as to shift for each adsorption unit 3, the pressure swing adsorption device. 2. A combiner 4 is provided between each of the separated gas surge tanks 5 and the product gas holder 7 and is capable of combining the separated gases, and the combiner 4 is also provided.
A merged gas control valve 6 capable of adjusting the flow rate of the separated gas sent to the merger 4 is provided between each of the separated gas surge tanks 5 and each of the separated gas surge tanks 5. The pressure swing adsorption device described.