KR20200018042A - Method of Removing Argon and Concentrating Nitrogen by Adsorbing and Separating Nitrogen from Gas Mixture of Argon and Nitrogen or Air - Google Patents

Abstract

The present invention relates to an adsorption separation method for removing mixture gas of argon and nitrogen or argon from air, and concentrating nitrogen, which passes through three or more pressure swing adsorption devices filled with an adsorbent from nitrogen gas containing argon or air to adsorb nitrogen to the adsorbent, so that argon that is not absorbed is discharged to an upper part of an adsorption tower to remove and recover nitrogen, thereby having an effect of producing a high concentration of nitrogen with argon removed from mixture gas of argon and nitrogen or air.

Description

Method of Removing Argon and Concentrating Nitrogen by Adsorbing and Separating Nitrogen from Gas Mixture of Argon and Nitrogen or Air}

The present invention relates to an adsorptive separation method of argon and nitrogen mixed gas or air to remove argon and condensing nitrogen, and more specifically, three or more pressure swing adsorption apparatuses filled with an adsorbent from nitrogen gas or air containing argon. Argon which is not adsorbed after adsorbing nitrogen to the adsorbent by passing through is discharged from the adsorption tower and removed and recovers the nitrogen, and the nitrogen concentration adsorption separation method for removing argon from argon and nitrogen gas mixture or air.

In general, pressure swing adsorption (PSA), which produces nitrogen, has commercialized techniques and methods for removing oxygen and producing nitrogen using molecular sieve carbon (Carbon Molecular Sieve, CMS). However, research on argon removal technology is not actively conducted.

As a technique for removing argon that is currently in progress, Japanese Laid-Open Patent Publication No. 2001-00269010 discloses a method and apparatus for producing nitrogen using CMS. When nitrogen is produced in this way, oxygen is removed but argon is not removed but remains in the product nitrogen. In addition, a technique and a method for recovering argon by removing nitrogen from argon-containing nitrogen gas have been developed. Japanese Laid-Open Patent Publication No. 2012-176848 discloses a method for purifying and recovering argon gas using X-zeolite. . In addition, as a method for producing argon gas using PSA in a mixed gas, Japanese Laid-Open Patent Publication No. 2009-022311 discloses an argon purifying method and an argon purifying apparatus, and Korean Patent No. 194-0007563 discloses ammonia purge gas. Disclosed are an adsorptive separation method and apparatus for separating argon and hydrogen at high concentrations. Using the prior art, it is possible to remove nitrogen and concentrate argon, but argon-free nitrogen cannot be obtained as a product.

Accordingly, the present inventors have made efforts to solve the above problems and to concentrate argon-removed nitrogen from argon-nitrogen mixed gas or air, and as a result, at least three pressure swing adsorptions filled with an adsorbent from argon-containing nitrogen gas or air After passing through the device to adsorb nitrogen to the adsorbent, argon that is not adsorbed is discharged from the adsorption tower and removed to recover nitrogen, which confirms that the argon-free nitrogen gas or argon-free nitrogen from air can be concentrated to a high concentration. The present invention has been completed.

It is an object of the present invention to provide a method and apparatus which can remove argon from an argon and nitrogen mixture gas or air and concentrate nitrogen to a high concentration.

In order to achieve the above object, the present invention (a) by introducing a mixed gas or air of argon and nitrogen into the adsorption tower filled with nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas to the nitrogen selective adsorbent and adsorption from the adsorption tower Adsorption step of discharging argon and oxygen which are not; (b) a rinsing step of introducing nitrogen of high purity (99.9 to 99.99%) into the adsorption tower where the adsorption step is completed to increase the purity of nitrogen in the adsorption tower while washing impurities remaining in the adsorption tower together with nitrogen; (c) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to discharge nitrogen existing in the adsorption tower, and desorbing in vacuum to discharge nitrogen adsorbed on the adsorbent; And (d) introducing the gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed and firstly accumulating the gas, and adsorbing nitrogen from the adsorption tower of the adsorption step and discharging the secondary gas into the adsorption tower. It provides a method of removing argon and concentrated separation of nitrogen from the argon and nitrogen mixed gas comprising a pressure storage step to accumulate.

The present invention also provides (a) introducing a mixed gas or air of argon and nitrogen into an adsorption tower filled with a nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas to a nitrogen selective adsorbent and to prevent argon and oxygen not adsorbed from the adsorption tower. Adsorption step of discharge; (b) a recovery step of recovering nitrogen in the nitrogen-containing gas by introducing nitrogen-containing gas discharged from the rinsing step of the adsorption tower to the adsorption tower where the adsorption step is completed; (c) a rinsing step of introducing nitrogen of high purity (99.90 to 99.99%) into the adsorption tower where the recovery step is completed to increase the purity of nitrogen in the adsorption tower while washing impurities remaining in the adsorption tower together with nitrogen; (d) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to discharge nitrogen present in the adsorption tower, and desorbing in vacuum to discharge nitrogen adsorbed on the adsorbent; And (e) firstly accumulating the gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed, and adsorbing nitrogen from the adsorption tower of the (a) adsorption step and discharging the secondary gas. It provides a method of removing argon and concentrated separation of nitrogen from the argon and nitrogen mixed gas comprising a pressure storage step to accumulate.

In the present invention, it is possible to obtain the effect of obtaining argon-removed nitrogen gas containing argon-containing nitrogen as a product.

1 is a 3bed pressure swing adsorption process for producing nitrogen from nitrogen-argon gas.
2 is a 4bed pressure swing adsorption process for producing nitrogen from nitrogen-argon gas.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

In the present invention, the mixed gas or air of argon and nitrogen is separated by selective adsorption of nitrogen in an adsorption tower filled with a nitrogen selective adsorbent, and argon is removed from nitrogen containing argon by a pressure swing adsorption method using an adsorbent to purify nitrogen with high purity. It was confirmed that it could be concentrated.

Accordingly, the present invention provides (a) introducing a mixed gas or air of argon and nitrogen into an adsorption tower filled with a nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas to a nitrogen selective adsorbent and not adsorb from the adsorption tower. Adsorption step of discharging argon and oxygen; (b) a rinsing step of introducing nitrogen of high purity (99.90 to 99.99%) into the adsorption tower where the adsorption step is completed to increase nitrogen purity in the adsorption tower while washing impurities remaining in the adsorption tower together with nitrogen; (c) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to discharge nitrogen existing in the adsorption tower, and desorbing in vacuum to discharge nitrogen adsorbed on the adsorbent; And (d) introducing the gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed and firstly accumulating the gas, and adsorbing nitrogen from the adsorption tower of the adsorption step and discharging the secondary gas into the adsorption tower. The present invention relates to a method for removing argon from a mixed gas of argon and nitrogen and a concentrated separation of nitrogen, including a step of accumulating pressure.

In another aspect, the present invention (a) by introducing a mixed gas or air of argon and nitrogen into the adsorption tower filled with a nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas to the nitrogen selective adsorbent and not adsorbed from the adsorption tower. Adsorption step of discharging argon and oxygen; (b) a recovery step of recovering nitrogen in the nitrogen-containing gas by introducing nitrogen-containing gas discharged from the rinsing step of the adsorption tower to the adsorption tower where the adsorption step is completed; (c) a rinsing step of introducing nitrogen of high purity (99.90 to 99.99%) into the adsorption tower where the recovery step is completed to increase the purity of nitrogen in the adsorption tower while washing impurities remaining in the adsorption tower together with nitrogen; (d) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to discharge nitrogen existing in the adsorption tower, and desorbing in vacuum to discharge nitrogen adsorbed on the adsorbent; And (e) firstly accumulating the gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed, and adsorbing nitrogen from the adsorption tower of the (a) adsorption step and discharging the secondary gas. The present invention relates to a method for removing argon from a mixed gas of argon and nitrogen and a concentrated separation of nitrogen, including a step of accumulating pressure.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is an apparatus and method for producing nitrogen at high concentration by removing argon contained in nitrogen or air by pressure swing adsorption. First, argon-containing nitrogen is primarily produced by selectively adsorbing oxygen by means of pressure swing adsorption using molecular sieve activated carbon in air. This is generally a process for producing nitrogen in the air. Nitrogen produced in this way contains about 1% of argon, so it does not meet the requirements of product nitrogen in the demand of less than 0.5% of argon. Therefore, in order to produce the required high purity nitrogen, argon may be removed by pressure swing adsorption using an adsorbent to concentrate the high purity nitrogen.

In the present invention, by passing through the pressure swing adsorption apparatus filled with the adsorbent from nitrogen gas or air containing about 1% of argon, the adsorbent is adsorbed with nitrogen, and then the argon not adsorbed is removed from the adsorption tower. The adsorbed nitrogen is decompressed using a vacuum or vacuum pump to obtain a high purity nitrogen product.

The present invention can manufacture and operate a pressure swing adsorption apparatus using four adsorption towers to increase the recovery rate, or operate a pressure swing adsorption apparatus using three adsorption towers to remove argon and recover nitrogen.

Hereinafter, the adsorptive separation apparatus and operation method for removing argon from nitrogen or air and concentrating nitrogen at a high concentration will be described in detail.

Adsorption separation process of the present invention is a process using three adsorption tower consisting of adsorption step-nitrogen rinsing step-desorption step-compression step, or adsorption step-recovery step-nitrogen rinsing step-desorption step-compression step To drive.

1 and 2 will be described in detail the method and apparatus according to the present invention.

A method of removing argon from nitrogen-argon mixed gas and producing nitrogen by an adsorptive separation process of at least three or four adsorption towers filled with nitrogen selective adsorbents, respectively, arranged in parallel to each other, wherein each adsorption tower is a three-bed process. In the case of the adsorption step, the rinse step, the desorption step and the accumulator step is progressed, and in the case of the four-bed process is carried out repeatedly while being carried out sequentially to the adsorption step, recovery step, rinse step, desorption step and accumulator step.

At this time, the operation in each of the adsorption tower, when operating 3 bed

(a) an adsorption step in which a mixed gas or air of argon and nitrogen is introduced into an adsorption tower filled with a nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas, while argon not adsorbed is discharged from the adsorption tower;

(b) a rinsing step of increasing the purity of nitrogen in the adsorption tower by introducing high-purity product nitrogen into the adsorption tower where the adsorption step is completed to clean impurities remaining in the adsorption tower together with nitrogen;

(c) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to obtain high purity nitrogen present in the adsorption tower as a product, and desorbing in vacuum to obtain nitrogen adsorbed to the adsorbent as a product; And

(d) introducing a gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed; It can be configured, the process is shown in FIG.

In the 4-bed operation, after the adsorption step (a), the nitrogen-containing gas discharged from the rinse step of the other adsorption tower is introduced into the adsorption tower where the adsorption step is completed to recover nitrogen in the nitrogen-containing gas. The recovery step may further include. That is, (a) an adsorption step of introducing a mixed gas into the adsorption tower to selectively adsorb nitrogen in the mixed gas, while argon and oxygen not adsorbed are discharged from the adsorption tower; (b) recovering nitrogen in the nitrogen-containing gas by introducing nitrogen-containing gas discharged from the nitrogen rinsing step of the other adsorption tower to the adsorption tower where the adsorption step is completed; (c) a rinsing step of introducing nitrogen into the adsorption tower where the recovery step is completed to increase nitrogen purity in the adsorption tower while cleaning impurities remaining in the adsorption tower together with nitrogen; (d) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to obtain high purity nitrogen present in the adsorption tower as a product, and desorbing in a vacuum to obtain nitrogen adsorbed to the adsorbent as a product; And (e) a pressure accumulating step of increasing the pressure up to the adsorption pressure by introducing a gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed, and the process is illustrated in FIG. 2.

In the present invention, three or more adsorption towers may be arranged in parallel with each other. Preferably, three to four adsorption towers may be arranged in parallel with each other.

Here, the nitrogen-argon separation method performs the adsorption step, the rinsing step and the desorption step, and the accumulating step at the same time by the operation of the at least three adsorption towers in the at least 3bed process, and the operation of the at least 4 adsorption towers in the 4bed process. By the same time, the adsorption step, recovery step, rinse step, desorption step and accumulating step can be performed respectively.

In other words, the adsorption step, the nitrogen rinse step, the desorption step, and the accumulating step in the three adsorption towers are repeatedly performed in different steps at the same time. The steps may be repeated in different steps at the same time.

In the present invention, the desorption step may be carried out under a pressure of -1 ~ 10bar and a temperature condition of -10 ~ 40 ℃.

In the adsorption step, higher available pressures may be applied. Adsorption pressure can be used from atmospheric pressure up to 30 bar and it is preferable to rinse at the adsorption pressure if possible in the rinse step. Accumulation pressure accumulates to adsorption pressure so that operation of the next adsorption step may be prevented. The operating temperature does not need to be adjusted separately.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are only for exemplifying the present invention, and it is apparent that various changes and modifications can be made within the scope and technical use of the present invention. Naturally, the modifications belong to the appended claims.

EXAMPLE

Example  1: Adsorption Separation Method of Nitrogen-Argon Mixture Gas

Table 1 and Table 2 show a process for producing a high concentration of nitrogen by introducing a nitrogen-argon mixed gas into the adsorptive separation process.

Table 1 shows the operation steps of the pressure swing adsorption system using three adsorption towers, and Table 2 shows the operation steps of the pressure swing adsorption systems using the four adsorption towers. As shown in Table 1 and Table 2, three, four adsorption towers (V-1, V-2, V-3, V-4) were operated by performing an adsorption step, a recovery step, a nitrogen rinsing step, and a desorption step, respectively. Can be.

Figure 1 shows a three-bed pressure swing adsorption device consisting of three main adsorption tower (V-1, 2, 3).

22 control valves are provided to control the flow of gas in each operation step, and are composed of a vacuum pump 21 for desorbing and recovering nitrogen from the main adsorption tower and a nitrogen compressor 24 for increasing the pressure of the product.

Operation of the nitrogen-producing device goes through the following operating steps. In the gas supplied to the adsorption tower V-1 through the valve 1, nitrogen, which is a strong adsorption component, is adsorbed to the adsorption tower, and the gas which is not adsorbed is discharged through the valve 6 to enter the argon reservoir T-3. After the adsorption, the adsorption tower V-2 enters the rinse step through which the cleaning gas flows in through the valve 9 and is discharged through 11. The rinse step lowers the partial pressure of the adsorbed impurities while washing the impurities present in the bulk in the adsorption column, thereby inducing desorption from the adsorption phase to the bulk phase, thereby increasing the purification effect of nitrogen. The gas sent in the rinse stage is high purity nitrogen gas stored in the product storage tank (T-1) produced as a product. While the adsorption step (V-1) and the rinse step (V-2) are performed at the same time, the other adsorption tower (V-3) enters the vacuum desorption step for producing a product. The valve 14 and the valve 20 are opened, and the product is reduced to a vacuum pressure by using the vacuum pump 21. The produced product nitrogen is compressed to a cleaning pressure (5bar) using a nitrogen compressor 24, part of it is used as a cleaning gas, and the rest is compressed to the required pressure with a nitrogen compressor and sent to the product nitrogen. In this way, each role completes one cycle.

In the next step, the adsorption tower of V-1 is adsorbed, and the adsorption tower (V-2) of the rinsing step is continuously rinsed to wash away the remaining impurities. However, in order to recover the high purity nitrogen discarded in the rinsing step, the valve 11 is closed, the valve 10 is opened, and the valves 14 and 20 of the adsorption tower (V-3) where the vacuum desorption step is completed are sent to send gas. Nitrogen gas can be recovered and accumulated at the same time.

The adsorption step of the adsorption tower (V-1) is still performed, and the adsorption tower (V-2) where the rinse process is completed has the valves (9, 10) closed and the valves (8, 22) open to the interior of the adsorption tower (V-2). The product is produced by reducing the pressure to atmospheric pressure to obtain nitrogen gas. Vacuum desorption to obtain nitrogen gas strongly adsorbed to the adsorbent is carried out in the next step of atmospheric desorption. The adsorption tower (V-3) accumulated through the rinse gas is made secondary pressure to the pressure up to the adsorption pressure. The valve 18 is opened and gas is sent from the argon reservoir T-3 to secondary storage.

This operation continues alternately in three adsorption towers, forming a cycle, and continuous operation.

Figure 2 is a four-bed pressure swing adsorption device consisting of four main adsorption tower (V-1, 2, 3, 4) to increase the recovery rate.

28 control valves are provided to control the flow of gas in each operation step, and are composed of a vacuum pump 27 for desorbing and recovering nitrogen from the main adsorption tower, and a nitrogen compressor 30 for increasing the pressure of the product.

Operation of the 4ed pressure swing adsorption system is carried out through the following operation steps. In the gas supplied to the adsorption tower V-1 through the valve 1, nitrogen, which is a strong adsorption component, is adsorbed to the adsorption tower, and the gas which is not adsorbed is discharged through the valve 6 to enter the argon reservoir T-3. In order to produce the nitrogen of the product, the adsorption tower (V-2), which has been rinsed, opens the valves 8 and 22 to start desorption at atmospheric pressure to reduce the pressure of the adsorption tower to atmospheric pressure. After the adsorption, the adsorption tower (V-4) performs a recovery step to adsorb nitrogen in the gas discharged from the adsorption tower (V-3) (nitrogen rinse step), and argon that is not adsorbed by opening the valves 23 and 25. To the atmosphere. The adsorption tower (V-3) performs a rinse step of washing the small amount of argon gas present in the adsorption tower by increasing the concentration of nitrogen by using the high concentration nitrogen gas obtained as a product by opening the valves 15 and 16 as a cleaning gas. The gas sent in the rinse stage is high purity nitrogen gas stored in the product storage tank (T-1) produced as a product.

The next step is a vacuum desorption step to produce more products while the other adsorption tower V-2 is produced while the adsorption step V-1 and the rinse step V-3 recovery step V-4 are simultaneously performed. The valves 8 and 26 are opened, and the product is reduced to a vacuum pressure by using the vacuum pump 27. The produced product nitrogen is compressed to the cleaning pressure (7bar) by using a nitrogen compressor 30, part of it is used as a cleaning gas, the rest is compressed to the required pressure with a nitrogen compressor and sent to the product nitrogen. In this way, each step completes one step.

In the next step, the adsorption tower (V-1) is adsorbed, and the adsorption tower (V-3) of the rinsing step continues the rinsing process to wash away the remaining impurities. However, in order to use the gas discharged from the adsorption tower of the recovery step (V-4) as the gas to accumulate, the valve 11 of the adsorption tower (V-2) having the vacuum desorption step is opened to accumulate the adsorption pressure.

This operation continues alternately in the four adsorption towers, forming a cycle, and continuous operation.

The above operation yields nitrogen with the product having an argon of 0.1% or less and a nitrogen purity of 99.90% to 99.99%.

If the source gas is dry air, oxygen and argon are included as impurities in the source gas, but the operation method is operated in the same manner as described above to obtain nitrogen from which oxygen and argon are removed from the product nitrogen. It contains a mixed gas containing argon, oxygen and nitrogen.

Having described the specific part of the present invention in detail, it will be apparent to those skilled in the art that the specific description is only a preferred embodiment, thereby not limiting the scope of the present invention. will be. Thus, the substantial scope of the present invention will be defined by the claims and their equivalents.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 25, 26, 28: valve
21, 27: vacuum pump
24, 30: nitrogen compressor
29, 31: flow meter
V-1, V-2, V-3, V-4: adsorption tower
T-1, T-2: Argon-free product nitrogen storage tank
T-3: nitrogen storage tank containing argon or oxygen

Claims (8)

Removal of argon and nitrogen concentration separation from argon and nitrogen gas mixture comprising the following steps:
(a) an adsorption step of introducing a mixed gas or air of argon and nitrogen into an adsorption tower filled with a nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas to a nitrogen selective adsorbent and to discharge argon and oxygen not adsorbed from the adsorption tower; ;
(b) a rinsing step of introducing nitrogen of high purity into the adsorption tower where the adsorption step is completed to increase the purity of nitrogen in the adsorption tower while washing impurities remaining in the adsorption tower together with nitrogen;
(c) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to discharge nitrogen present in the adsorption tower, and desorbing in vacuum to discharge nitrogen adsorbed on the adsorbent; And
(d) introducing the gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed, and firstly accumulating the gas; Accumulating step.
Removal of argon and nitrogen concentration separation from argon and nitrogen gas mixture comprising the following steps:
(a) an adsorption step of introducing a mixed gas or air of argon and nitrogen into an adsorption tower filled with a nitrogen selective adsorbent to selectively adsorb nitrogen in the mixed gas to a nitrogen selective adsorbent and to discharge argon and oxygen not adsorbed from the adsorption tower; ;
(b) a recovery step of recovering nitrogen in the nitrogen-containing gas by introducing a nitrogen-containing gas discharged from the rinsing step of the adsorption tower to the adsorption tower where the adsorption step is completed;
(c) a rinsing step of introducing nitrogen of high purity into the adsorption tower where the recovery step is completed to increase the purity of nitrogen in the adsorption tower while washing impurities remaining in the adsorption tower together with nitrogen;
(d) a desorption step of depressurizing the adsorption tower after the rinsing step to atmospheric pressure to discharge nitrogen existing in the adsorption tower, and desorbing in vacuum to discharge nitrogen adsorbed on the adsorbent; And
(e) introducing the gas discharged from the adsorption tower of the rinsing step into the adsorption tower where the desorption step is completed, and firstly accumulating the gas; Accumulating step.
[3] The method of claim 1 or 2, wherein the adsorption tower has three or more adsorption towers arranged in parallel to each other.
The method of claim 2, wherein the adsorption tower has four adsorption towers arranged in parallel with each other to remove argon from the argon and nitrogen gas mixture and nitrogen separation method.
The method of claim 1, wherein the adsorptive separation method removes argon from argon and nitrogen mixed gas, characterized in that the adsorption step, the rinse step, the desorption step and the accumulating step are performed at the same time by the operation of the respective adsorption towers. Nitrogen concentrated separation method.
The method of claim 2, wherein the adsorptive separation method is characterized in that the adsorption step, the recovery step, the rinse step, the desorption step and the accumulating step are performed at the same time by the operation of the respective adsorption towers. Removal and Concentration Separation of Nitrogen.
The method of claim 1 or 2, wherein the nitrogen selective adsorbent is one or more selected from the group consisting of activated carbon, alumina, zeolite and MOF adsorbent.
The method of claim 1 or 2, wherein the desorption step is performed under a pressure of −1 to 10 bar and a temperature of −10 to 40 ° C. to remove argon from an argon and nitrogen mixed gas and to concentrate nitrogen.

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