JP3043282B2 - Gas purification method and apparatus used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas purification method capable of obtaining high-purity hydrogen required in the semiconductor industry and the like, and an apparatus used therefor.

[0002]

2. Description of the Related Art Conventionally, in a hydrogen (H ₂ ) producing apparatus using fossil fuel or the like as a raw material, a raw material such as LPG, NG, and naphtha is passed through a steam reforming process or a CO shift process, and the H ₂ gas component is reduced. A mixed gas containing about 46.2% (about 74% without water) is produced, and then the mixed gas is mixed with hydrogen PSA.
High-purity 99.9 to 99.999% by introducing it to a device (a device that alternately operates [adsorbs and regenerates] a plurality of adsorption towers and adsorbs impurities into the adsorption tower to purify hydrogen) Is becoming The H ₂ gas produced in this manner is supplied to a user after being filled in a cylinder or a cardle. However, H ₂ gas used by semiconductor users and the like is 99.9%.
Because it is necessary to make ultra-high purity to about 9999%,
The produced H ₂ gas is purified. That is, in the semiconductor manufacturing plant and the like, a refining device is attached upstream of a H ₂ supply line for supplying H ₂ gas in the cylinder and the curdle to a processing room, a working room, and the like in the plant. By using a Pd permeable membrane and a low-temperature adsorption means provided in this purifying apparatus, H ₂ gas in a cylinder or a curdle is ultra-purified to about 99.99999% and then supplied to the processing chamber or the like. .

[0003] However, in the above method, in addition to the installation cost of the H ₂ production apparatus, the installation cost of the refining apparatus, the transportation cost of the curdle, and the like are required.
The unit cost of H ₂ production increases. The yield of H ₂ gas after purification is about 75%, which also causes an increase in the unit cost of H ₂ production. Therefore, it is conceivable to eliminate the hydrogen PAS device and directly purify it with a Pd permeable membrane or low-temperature adsorption means, but in the case of using a Pd permeable membrane,
Both methods have been realized because the Pd film is expensive and has a low yield, and when using a low-temperature adsorption means, the apparatus becomes large-scale and there are problems such as clogging due to solidification of CO _2. There is no fact.

The present invention has been made in view of such circumstances, and has been developed in view of the high purity (9) required in a semiconductor manufacturing plant or the like.
It is an object of the present invention to provide a gas purification method capable of obtaining hydrogen of about 9.999999%) and an apparatus used therefor.

[0005]

In order to achieve the above object, the present invention is directed to a mixed gas containing H ₂ which is introduced into a dehumidifying step to remove moisture in the mixed gas, thereby removing the mixed gas. Is introduced into the low-temperature adsorption step to adsorb and remove impurities in the mixed gas, and the mixed gas from which the impurities are adsorbed and removed is introduced into the cryogenic adsorption step to adsorb and remove minute impurities in the mixed gas so as to be purified. the gas purification method as a first aspect, H ₂
And a dehumidifying tower for removing moisture in the mixed gas supplied from the supply pipe, and introducing the mixed gas from which moisture has been removed in the dehumidifying tower to adsorb impurities in the mixed gas. A gas purification apparatus comprising a low-temperature adsorption tower for removing and a cryogenic adsorption tower for introducing a mixed gas from which impurities are adsorbed and removed by the low-temperature adsorption tower and adsorbing and removing minute impurities in the mixed gas to purify the second gas is used as a second gas purification apparatus. The summary of the

That is, in the gas purification method of the present invention, first, in the first stage dehumidification step, moisture contained in the mixed gas containing H ₂ is removed, and then in the second stage low temperature adsorption step, the mixed gas is removed. Most of the CH ₄ , CO and CO ₂ contained in the mixed gas are adsorbed and removed at a low temperature (for example, at around −70 ° C.), and thereafter, in the third-stage cryogenic adsorption step, a very small amount of CH ₄ remaining in the mixed gas is removed. , CO at cryogenic temperatures (eg, at liquid nitrogen temperatures). Thus, the purification method of the present invention performs a three-stage dehumidification or adsorption step,
In the adsorption step, low-temperature adsorption and cryogenic adsorption are combined. Therefore, ultra-high-purity H ₂ (purity of 99.9999% or more) can be obtained.

[0007] Thus, according to the gas purification method of the present invention, it is possible to obtain of H ₂ in ultrapure about 99.99999, it is sufficient installation costs of H ₂ production apparatus,
There is no need for installation costs for the refining device, transportation costs for the curdles, and the like, and the cost is very low. Therefore, H ₂ production original bid is reduced. Further, the yield of H ₂ gas when extracting H ₂ from the mixed gas is as high as 95% or more, which also causes a decrease in the unit cost of H ₂ production. Also, compared to the case where the hydrogen PAS device is omitted and the purification is directly performed by the Pd permeable membrane or the low-temperature adsorption means, the cost is lower and the yield is higher than in the case of the Pd permeable membrane. Further, compared with the case of using the low-temperature adsorption means, the size becomes small and there is no problem such as blockage due to solidification of CO ₂ . On the other hand, with the device of the present invention, the above excellent method can be easily realized.

[0008]

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

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, reference numeral 1 denotes a cooler which cools a mixed gas (about 350 ° C.) supplied from a mixed gas supply pipe 13 to 35.
It acts to cool to about ° C. This mixed gas is H ₂ :
46.2% by weight (hereinafter abbreviated as%), CO ₂ : 12.7
%, CO: 2.0%, CH 4: 1.5%, H 2 O: 3
A mixed gas containing 7.6%, and 440 Nm ³ / h
Is supplied to the cooler 1. This gas mixture
This is a mixed gas reformed through the following two steps. That is, LPG (propane gas) is converted into a steam reforming step (LPG).
Is mixed with steam and introduced into the reforming furnace at a predetermined temperature, and CH ₄ and H ₂ O are reacted by the catalyst of the reforming furnace to obtain H _2.
Through a CO conversion process (reacting CO in the synthesis gas reformed in the steam reforming process with H ₂ O to convert it into H ₂ ). Thus, it is reformed to obtain a mixed gas of the above components.

Reference numerals 2 and 3 denote dehumidification towers having the same structure, and include activated alumina as a dehumidifier. This dehumidifier acts to remove H ₂ O in the mixed gas passed through the cooler 1. Heaters 2a and 3a used at the time of heating and regeneration are disposed outside the dehumidifying towers 2 and 3 respectively. Reference numeral 4 denotes a first heat exchanger in which a dehumidification tower 2 is provided.
3 mixed gas passage 4a the mixed gas passes that through, and GN ₂ passage 4b through which liquefied nitrogen gas through the GN ₂ passages 15 and 17 in the low temperature adsorption tower 5, 6 (GN _2), low-temperature adsorption tower 5 , H ₂ passage 4c through which H ₂ passing through of H ₂ passages 16 and 18 in 6 is formed. And each passage 4a ~
The heat exchange of the mixed gas, GN ₂ , and H ₂ passing through 4c lowers the temperature of the mixed gas to about −40 ° C., raises the temperature of GN ₂ to about 30 ° C., and raises the temperature of H ₂ to about 30 ° C. I do.

Reference numerals 5 and 6 denote low-temperature adsorption towers having the same structure.
The low-temperature adsorption towers 5, 6 are synthesized as adsorbents 5a, 6a.
Zeolite is built in and the adsorbent 5
a, 6a so as to penetrate_TwoPassages 15, 17
And H_TwoPassages 16 and 18 are built in (in FIG.
Although the adhesives 5a and 6a are shown in a state divided into three,
In fact, they are formed integrally). And each adsorbent 5
a, mixed gas passing through 6a and passing through each passage 15-18
GN_Two, H_TwoTo lower the temperature of the mixed gas to about -70 ° C.
GN_TwoIs raised to about -80 ° C, and H_TwoTo -80 ° C
It acts to raise the temperature to a certain degree. Such an adsorbent 5a,
6a is a low-temperature state of about -70 ° C.
O, CH_FourAnd CO_TwoTo adsorb and remove most of
I do. Reference numeral 7 denotes a second heat exchanger in which low-temperature adsorption is performed.
Mixed gas passage 7a through which the mixed gas passes through towers 5 and 6
And the inner towers 10a and 11a of the cryogenic adsorption towers 8 and 9
Purified H _TwoH through_TwoPassage 7b, cryogenic adsorption towers 8, 9
Generated in the outer towers 10b and 11b_TwoGN through which_Twoaisle
7c is formed. Then, through each of the passages 7a to 7c
Mixed gas, GN_Two, H_TwoGas mixture by heat exchange
Lower the temperature to about -180 ° C, GN_TwoTo about -80 ° C
Let warm, H_TwoTo raise the temperature to about -80 ° C.

Reference numerals 8 and 9 denote cryogenic adsorption towers having the same structure.
It has a double structure consisting of inner cylinders 10a, 11a and outer towers 10b, 11b. In the outer towers 10b and 11b, the inner towers 10a and 11a are cooled to a low temperature (-170 to -196).
(About ° C). on the other hand,
The inner towers 10a and 11a have a built-in adsorbent that adsorbs and removes CH ₄ and CO (trace impurities) in the mixed gas at the low temperature. Activated carbon is used as such an adsorbent. Reference numeral 12 denotes an LN ₂ storage tank which stores liquid nitrogen (L) in the outer towers 10b and 11b of the cryogenic adsorption towers 8 and 9.
N ₂ ). Reference numeral 19 denotes a product hydrogen extraction pipe for extracting purified H ₂ passed through the low-temperature adsorption towers 5 and 6 as product hydrogen. In the dehumidifying towers 2 and 3 as described above, H ₂ in the mixed gas is used.
O removal and regeneration of the dehumidifier are alternately repeated,
In the low-temperature adsorption towers 5 and 6 and the cryogenic adsorption towers 8 and 9, the removal of impurities in the mixed gas and the regeneration of the adsorbent are alternately repeated. In the figure, reference numeral 90 denotes a cold box which houses therein the low-temperature adsorption towers 5, 6, the second heat exchanger 7, and the cryogenic adsorption towers 8, 9.

On the other hand, the cooler 1 and the dehumidifying towers 2 and 3 are connected by the following piping. That is, the cooler 1 is connected to the first dehumidifying tower 2 by a pipe 20 and a pipe 21 with an on-off valve 21a, and connected to the second dehumidifying tower 3 by a pipe 20 and an on-off valve 22.
They are connected by a pipe 22 with a. And both pipes 21,
22 is connected by a pipe 23 with both on-off valves 23a and 23b,
A fuel reuse pipe 24 extends from a portion of the pipe 23 between the on-off valves 23a and 23b.

The two dehumidifying towers 2 and 3 and the first heat exchanger 4 are connected by the following piping. That is, the mixed gas passage 4 a of the first heat exchanger 4 is connected to the first dehumidification tower 2 by the on-off valve 25.
The pipes 25 and 26 are connected by the pipes 25 and 26, respectively, and are connected to the second dehumidification tower 3 by the pipes 27 and 26 with the open / close valve 27a. 2
Reference numeral 8 denotes a pipe with an on-off valve 28a connecting the two pipes 25 and 27.

The first heat exchanger 4 and the low-temperature adsorption towers 5 and 6 are connected by the following piping. That is, the mixed gas passage 4a of the first heat exchanger 4 is connected to the first low-temperature adsorption tower 5 by a pipe 31 and a pipe 29 with an on-off valve 29a, and connected to the second low-temperature adsorption tower 6 by a pipe 31 and a pipe 30 with an on-off valve 30a. Are connected by These two pipes 29 and 30 are provided with two on-off valves 32.
A fuel reuse pipe 44 extends from a portion of the pipe 32 between the on-off valves 32a and 32b. The GN ₂ passage 4b of the first heat exchanger 4 is connected to the GN ₂ passage 15 in the first low-temperature adsorption tower 5 by a pipe 33 and a pipe 34 with an on-off valve 34a.
A pipe 33 and a pipe 35 with an on-off valve 35a are connected to the N ₂ passage 17. 36 is a GN ₂ passage 4b of the first heat exchanger 4
A closing valve 36a with GN ₂ take-out pipe extending from. 3
Reference numerals 7 and 38 denote on-off valves 37a and 3 extending from pipes 34 and 35, respectively.
It is a vent pipe with 8a. In addition, H _{2 of} the first heat exchanger 4
The passage 4 c is connected to the H ₂ passage 16 in the first low-temperature adsorption tower 5 by a pipe 3.
9, connected by a pipe 40 with an on-off valve 40a, and connected to the H ₂ passage 18 in the second low-temperature adsorption tower 6 by a pipe 39 and a pipe 41 with an on-off valve 41a. These two pipes 40, 41 are connected by a pipe 42 with both on-off valves 42a, 42b.
A fuel reuse pipe 43 extends from a portion between the two on-off valves 42a and 42b.

The low-temperature adsorption towers 5 and 6 and the second heat exchanger 7 are connected by the following pipes. That is, the mixed gas passage 7a of the second heat exchanger 7 is connected to the first low-temperature adsorption tower 5 by the pipe 45 and the pipe 46 with the on-off valve 45a, and the second low-temperature adsorption tower 6 is connected to the pipe 47 and the pipe 46 with the on-off valve 47a. Are connected by Moreover, H ₂ passage 7b of the second heat exchanger 7 are off valve 48a with the pipe 48 in H ₂ passage 16 of the first low temperature adsorption tower 5, connected by pipes 49, H ₂ in the second low temperature adsorption tower 6
The pipe 18 is connected to the passage 18 by a pipe 50 with an on-off valve 50 a and a pipe 49. Further, the GN ₂ passage 7c of the second heat exchanger 7 is connected to the GN ₂ passage 15 in the first low-temperature adsorption tower 5 by a pipe 51 with an on-off valve 51a and a pipe 52.
The N ₂ passage 17 is connected to a pipe 53 with an on-off valve 53 a and a pipe 52.

The second heat exchanger 7 and the cryogenic adsorption towers 8 and 9 are connected by the following piping. That is, the mixed gas passage 7a of the second heat exchanger 7 is connected to the first cryogenic adsorption tower 8
Is connected to the inner cylinder 10a of the second cryogenic adsorption tower 9 by a pipe 55 and a pipe 56 with an on-off valve 56a.
They are connected by a pipe 57 with an on-off valve 57a. Also, the second
The H ₂ passage 7 b of the heat exchanger 7 is connected to the inner cylinder 10 a of the first cryogenic adsorption tower 8 by a pipe 58 and a pipe 59 with an on-off valve 58 a, and the on-off valve 60 a is connected to the inner cylinder 11 a of the second cryogenic adsorption tower 9. The pipes 60 and 59 are connected to each other. The GN ₂ passage 7 c of the second heat exchanger 7 is connected to the outer cylinder 1 of the first cryogenic adsorption tower 8.
0b with a pipe 61 with an on-off valve 61a and a pipe 62,
The outer tube 11b of the second cryogenic adsorption tower 9 is connected to a pipe 63 with an on-off valve 63a and a pipe 62. 64 is piping 56,5
7 is a pipe with both on-off valves 64a and 64b connecting
A fuel reuse pipe 65 extends from a portion of the pipe 64 between the on-off valves 64a and 64b.

The GN ₂ extraction pipe 36 is connected to a pipe 58 extending from the inner cylinder 10a of the first cryogenic adsorption tower 8 by a pipe 66 with an open / close valve 66a and a pipe 67, and is connected to the inner cylinder of the second cryogenic adsorption tower 9. A pipe 60 extending from 11a is connected to a pipe 68 with an open / close valve 68a and a pipe 67. The pipe 67 extends from the GN ₂ passage 15 in the first low-temperature adsorption tower 5.
1 and a pipe 53 connected to a pipe 69 with an on-off valve 69a and a pipe 70 and extending from the GN ₂ passage 17 in the second low-temperature adsorption tower 6.
Are connected to a pipe 71 with an on-off valve 71a and a pipe 70. On the other hand, the product hydrogen extraction pipe 19 is connected to the pipe 45 by a pipe 72 with an on-off valve 72a and a pipe 73, and
Are connected to a pipe 74 with an on-off valve 74a and a pipe 73. 75 is an on-off valve 75a connecting the pipes 48 and 50,
A pipe 75 b is provided with a pipe 76 extending from between the on-off valves 75 a and 75 b and connected to the pipe 72.

The cryogenic adsorption towers 8 and 9 and the LN ₂ storage tank 12 are connected by the following piping. That is, L
The N ₂ storage tank 12 is connected to the outer cylinder 10b of the first cryogenic adsorption tower 8 by a pipe 80 and a pipe 81 with an on-off valve 80a, and is connected to the outer cylinder 11b of the second cryogenic adsorption tower 9 by a pipe 82 with an on-off valve 82a. It is connected by 81. 83, 84 each outer cylinder 10b, 1
1b is a relief valve.

In the above apparatus, the first dehumidifying tower 2, the first
The operation when the low-temperature adsorption tower 5 and the first cryogenic adsorption tower 8 are used in the regeneration step and the second dehumidification tower 3, the second low-temperature adsorption tower 6 and the second cryogenic adsorption tower 9 are used in the step of removing impurities and the like is shown. This will be described with reference to FIGS. 2 to 4,
An arrow indicates that the on-off valve is in the open state, and indicates that the on-off valve is in the closed state by blacking out the valve. The impurities removing step, first, the pipe from the LN ₂ tank 12 LN ₂ out tower 11b of the second cryogenic adsorption tower 9 8
Introduced and supplied via 1,82. Next, the mixed gas supplied from the mixed gas supply pipe 13 is cooled by the cooler 1, and then introduced into the second dehumidification tower 3 via the pipes 20 and 22, where the H ₂ O in the mixed gas is Is removed, and the mixed gas passage 4a of the first heat exchanger 4 is
To be introduced. In the first heat exchanger 4, the second low-temperature adsorption tower 6
After heat exchange with H ₂ and GN ₂ which passed through
The mixture is introduced into the second low-temperature adsorption tower 6 via 1, 30 where most of CO, CH ₄ and CO ₂ in the mixed gas are adsorbed and removed. Next, the mixed gas that has passed through the second low-temperature adsorption tower 6 is supplied to the mixed gas passage 7 of the second heat exchanger 7 through pipes 47 and 46.
a, and heat-exchanged with H ₂ passed through the inner tower 11a of the second cryogenic adsorption tower 9 and GN ₂ sent from the outer tower 11b of the second cryogenic adsorption tower 9 to lower the temperature. Piping 55, 57
, Is introduced into the inner column 11a of the second cryogenic adsorption tower 9, where the trace amounts of impurities CH ₄ and CO in the mixed gas are adsorbed and removed. Next, purified H ₂ that has passed through the inner column 11 a of the second cryogenic adsorption tower 9 is supplied to the pipes 60 and 59, the H ₂ passage 7 b of the second heat exchanger 7, pipes 49 and 50, and the second low temperature adsorption tower 6. H ₂ passage 18, pipes 41 and 39, H ₂ passage 4 c of first heat exchanger 4
Through the product hydrogen extraction pipe 19. At this time,
The second heat exchanger 7, the second low-temperature adsorption tower 6, and the passages 7b, 18, and 4c of the first heat exchanger 4 perform a heat exchange action. Thus, the product H ₂ taken out from the product hydrogen take-out pipe 19
Has been ultra-purified to about 99.99999%, and has a production amount of 170 Nm ³ / h.

On the other hand, in the regeneration step, the dehumidifier of the first dehumidification tower 2 is regenerated as follows. During this regeneration, the on-off valve 28a of the pipe 28 is opened. Then
The first heater 2a is heated to about 200 ° C., and the first dehumidifying tower 2 is heated at this high temperature to desorb H ₂ O adsorbed by the adsorbent in the first dehumidifying tower 2. Next, the mixed gas from which the water has been adsorbed and removed in the second dehumidifying tower 3 is introduced into the first dehumidifying tower 2 via a pipe 28, and the mixed gas is used to remove moisture in the first dehumidifying tower 2 and dry the mixed gas. And discharged from the first dehumidification tower 2. The discharged mixed gas is supplied to the fuel reuse pipe 24 for reuse. Thereby, the dehumidifying agent of the first dehumidifying tower 2 is regenerated.

The adsorbent 5a of the first low-temperature adsorption tower 5 is
It is reproduced as follows. That is, first, the GN ₂ generated in the outer cylinder 11b of the second cryogenic adsorption tower 9 to GN ₂ passage 15 of the first low temperature adsorption column 5, pipes 63, 62, GN ₂ passage 7c of the second heat exchanger 7 , Pipes 52 and 53, the GN ₂ passage 17 of the second low-temperature adsorption tower 6, the pipes 35 and 33, the GN ₂ passage 4b of the first heat exchanger 4, and the pipes 36, 67, 70 and 69 (introduction). Sometimes GN ₂ is at room temperature). On the other hand, the normal-temperature product H ₂ passing through the product hydrogen extraction pipe 19 is supplied to the H ₂ passage 16 of the first low-temperature adsorption tower 5 through the pipes 73, 72, and 73.
Introduced via 76,75. By introducing these GN ₂ and H ₂ , the inside of the first low-temperature adsorption tower 5 is heated to about 20 ° C.
After that, the normal-temperature product H ₂ passing through the product hydrogen extraction pipe 19 is introduced into the first low-temperature adsorption tower 5 through the pipes 73, 72, and 45. As a result, CO, C adsorbed by the adsorbent 5a
H ₄ and CO ₂ are desorbed from the adsorbent 5a and the product H ₂
And discharged from the first low-temperature adsorption tower 5. Product H ₂ this that discharged is via pipes 29 and 32, a fuel recycling pipe 44 and reused. Thereby, the adsorbent 5 of the first low-temperature adsorption tower 5
a is reproduced.

Further, the inner column 10a of the first cryogenic adsorption column 8
The adsorbent is regenerated as follows. First, the on-off valve
83 to open the LN in the outer tower 10b._TwoDischarge all
deep. Next, the second tower 10a of the first cryogenic adsorption tower 8 is
GN generated in the outer cylinder 11b of the cryogenic adsorption tower 9_TwoAnd piping 6
3,62, GN of the second heat exchanger 7_TwoPassage 7c, piping 5
2,53, GN of the second low-temperature adsorption tower 6_TwoPassage 17, piping 3
5,33, GN of the first heat exchanger 4_TwoPassage 4b, piping 3
6, 67, 66, 58 (GN at the time of introduction)_Two
Is at room temperature), the inner tower 10a is heated to about 20 ° C.
After that, this GN _TwoContinue to introduce. And adsorbent
CO, CH adsorbed on_FourIs desorbed from the adsorbent and the first electrode
It is discharged from the inner tower 10a of the low-temperature adsorption tower 8. This discharged
GN_TwoThrough the pipes 56 and 64 and the fuel reuse pipe 65
Used.

In the above apparatus, the first dehumidifying tower 2,
When the first low-temperature adsorption tower 5 and the first cryogenic adsorption tower 8 are used in the step of removing impurities and the like, and the second dehumidification tower 3, the second low-temperature adsorption tower 6 and the second cryogenic adsorption tower 9 are used in the regeneration step, The opening and closing of each on-off valve is reversed from the state shown in FIG. However, the on-off valve 28a opens and the on-off valve 36a closes.

As described above, in this embodiment, H ₂ having a purity of 99.99999% or more can be obtained from the reformed gas. Therefore, it is possible to omit the installation cost of the conventional refining apparatus and the transportation cost of the curdle, and the like.
It is cheap. In particular, on-site system in (the manufacturer is established the H ₂ production unit to the user of the plant site, the installation cost method manufacturers will bear), is no longer necessary equipment costs. Therefore, H ₂ production original bid is reduced. Further, the yield of H ₂ gas is as high as 95% or more, which also causes a decrease in the unit cost of H ₂ production.

In the above embodiment, the dehumidifying towers 2, 3
Activated alumina is used as a dehumidifier, but the present invention is not limited thereto, and synthetic zeolite may be used. In addition, synthetic zeolites are used as adsorbents for the low-temperature adsorption towers 5 and 6, but are not limited thereto.
Activated carbon may be used. Activated carbon is used as an adsorbent for the cryogenic adsorption towers 8 and 9; however, the present invention is not limited to this, and a synthetic zeolite may be used.

[0027]

As described above, according to the purification method of the present invention,
If a three-stage dehumidification or adsorption process is performed,
Now, because low-temperature adsorption and cryogenic adsorption are combined,
H of ultra-high purity (purity of 99.9999% or more)_TwoGet
Can be Therefore, H_TwoInstallation costs for manufacturing equipment
Only the cost of installing the refining equipment and transporting the curdle
Is not required, and the cost is very low. For this reason,
H_TwoThe production unit price decreases. Also, H_TwoGas yield 9
As high as 5% or more, this is also H_TwoCauses of lower unit cost of production
Becomes In addition, the hydrogen PAS device was deleted and the Pd permeable membrane and
Compared to the case of direct ultra-high purification by low-temperature adsorption means
Therefore, it is cheaper and higher yield than the case using the Pd permeable membrane.
You. In addition, compared to the case using low-temperature adsorption means,
And CO _TwoThere is no problem such as blockage due to solidification of the material. one
On the other hand, with the device of the present invention, the above excellent method can be easily realized.
can do.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a gas purification device according to an embodiment of the present invention.

FIG. 2 is an enlarged partial configuration diagram showing an operation of the gas purification device.

FIG. 3 is an enlarged partial configuration diagram showing an operation of the gas purification device.

FIG. 4 is an enlarged partial configuration diagram showing an operation of the gas purification device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooler 2, 3 Dehumidification tower 4 1st heat exchanger 5, 6 Low temperature adsorption tower 7 2nd heat exchanger 8, 9 Cryogenic adsorption tower

Continuation of front page (72) Inventor Nobuhisa Kikuchi 2-6-6 Chikushinmachi, Sakai-shi, Osaka Daido Hokusan Co., Ltd. Sakai Plant (56) References JP-A-52-62177 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) C01B 3/56

Claims (5)

(57) [Claims] 1. A mixed gas containing H ₂ is introduced into a dehumidification step to remove moisture in the mixed gas, and the mixed gas from which moisture has been removed is introduced into a low-temperature adsorption step to adsorb and remove impurities in the mixed gas. A gas purification method characterized by introducing a mixed gas from which impurities have been removed by adsorption to a cryogenic adsorption step to adsorb and remove minute impurities in the mixed gas to purify the mixed gas. 2. The gas purification method according to claim 1, wherein the dehumidifying step is performed in a dehumidifying tower containing activated alumina. 3. The gas purification method according to claim 1, wherein the low-temperature adsorption step is performed in a low-temperature adsorption tower containing a synthetic zeolite. 4. The gas purification method according to claim 1, wherein the cryogenic adsorption step is performed in a cryogenic adsorption tower comprising an inner tower containing activated carbon and an outer tower containing liquid nitrogen. 5. A supply pipe for a mixed gas containing H ₂ , a dehumidification tower for removing moisture in the mixed gas supplied from the supply pipe, and a mixed gas from which moisture has been removed by the dehumidification tower. A low-temperature adsorption tower that adsorbs and removes impurities in the mixed gas; and a cryogenic adsorption tower that introduces the mixed gas from which the impurities have been adsorbed and removed by the low-temperature adsorption tower, adsorbs and removes minute impurities in the mixed gas, and purifies the mixture. A gas purification device characterized by the above-mentioned.