JP2005246137A - Method and apparatus for gas separation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas separation method and an apparatus therefor capable of efficiently removing fine amount gas components such as helium and hydrogen from a gaseous mixture containing high value added gases such as krypton and xenon, and continuously separating, refining, circulating and recycling the high value added gas at a high recovery rate. <P>SOLUTION: An adsorbing process of introducing the gaseous mixture containing the high value gas which is at least one kind of krypton, xenon and neon into an adsorption cylinder filled with an absorbent for which the high value added gas is an easy-to-absorb component, making the adsorbent adsorb the high value added gas and discharging an impurity gas not adsorbed by the adsorbent from the adsorption cylinder, and a regenerating process of evacuating the adsorption cylinder, desorbing the high value added gas from the absorbent, introducing a purge gas from the outside of a system to the absorption cylinder and making the gas inside the cylinder flow out are performed. A part of the gas flowing out from the adsorption cylinder in the regenerating process is circulated to and mixed into the gas mixture and a residual part is recovered. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gas separation method and apparatus, and more specifically, removes the impurities by treating a mixed gas containing at least one high value-added gas of krypton, xenon and neon by a pressure fluctuation adsorption separation method, The present invention relates to a gas separation method and apparatus for separating and collecting the high value-added gas to a reusable state.

  In the process of manufacturing a semiconductor product such as a semiconductor integrated circuit, a liquid crystal panel, a solar cell and its panel, a magnetic disk, etc., manufacturing is performed in which plasma is generated in an inert gas atmosphere and the semiconductor product or display device is processed by the plasma. Equipment is widely used. Conventionally, helium or argon has been used as an inert gas in such treatment, but in recent years, treatment using a high value-added gas such as krypton, xenon, or neon has been performed in order to perform more advanced treatment. Attention has been paid.

  Krypton and xenon are extremely expensive gases (high value-added gases) due to the abundance ratio in the air and the complexity of the separation process, and in order to establish a process using such high value-added gas economically. It is essential to separate and purify high value-added gas from used exhaust gas at a high recovery rate and recycle it. Furthermore, the impurity concentration of the recovered high value-added gas is desired to have a high purity of 100 ppm or less.

  Here, the exhaust gas containing the high value-added gas to be separated and refined is a mixed gas in which the high-value-added gas that is the atmosphere gas and nitrogen introduced into the vacuum exhaust means of the semiconductor manufacturing facility are the main gas components. It is in a state. Other components in the exhaust gas include gas components that are added depending on the purpose of manufacturing the semiconductor. For example, oxygen is included in plasma oxidation, nitrogen, hydrogen, ammonia, and nitric oxide compounds are included in plasma nitridation, and metal hydride-based gases are included in plasma CVD. For example, a halogenated hydrocarbon gas is included. Furthermore, water, carbon monoxide, carbon dioxide, hydrogen, hydrocarbons are included as reaction byproducts of the plasma treatment, and helium used for cooling the semiconductor substrate is also included.

  Hereinafter, the process of a semiconductor manufacturing apparatus and the gas component discharged | emitted at each process are demonstrated in detail. First, the inside of the chamber before inserting the substrate to be subjected to plasma processing is made a clean nitrogen atmosphere by evacuating it while ventilating nitrogen. Thereafter, the substrate is inserted into the processing chamber, but nitrogen aeration and evacuation are continued to maintain a clean nitrogen atmosphere.

  Next, after the gas flowing in the chamber is switched from nitrogen to a high value-added gas and the inside of the processing chamber is in a high value-added gas atmosphere, plasma processing is started. Therefore, the gas exhausted from the chamber during the plasma processing is mainly occupied by high-value-added gas, but also includes gas components and reaction byproducts added depending on the manufacturing purpose.

  After the plasma processing is completed, the semiconductor manufacturing apparatus stops the plasma by stopping the high frequency application. At this time, the circulating gas is switched from the high added value gas to nitrogen, and then the substrate is taken out. Therefore, the gas exhausted during this period includes nitrogen as a main gas component, but also includes high value-added gas remaining in the system and helium used for cooling the substrate.

  Also, nitrogen is vented between the processing chamber and the evacuation system regardless of the process in order to prevent back diffusion of impurities from the evacuation system. The nitrogen for preventing back diffusion is exhausted together with the gas exhausted from the processing chamber. Further, nitrogen is also vented to the bearing portion of the vacuum pump for preventing air entrainment. A part of this nitrogen flows into the vacuum exhaust system and is exhausted together with the above-mentioned gas.

  As a method for separating and recovering a target gas component from a mixed gas, a pressure fluctuation adsorption separation (PSA) method is widely known. For example, when air is used as a raw material and oxygen is obtained as a product, zeolite is used as an adsorbent, and air is circulated under pressure to adsorb and fix nitrogen, which is an easily adsorbed component, to the adsorbent. Collect oxygen as a product. Next, when the adsorbent layer is placed under a pressure condition sufficiently lower than the air flow step, the nitrogen adsorbed on the adsorbent is desorbed. The PSA operation, which repeats the adsorption operation at a relatively high pressure and the regeneration operation at a relatively low pressure, can be switched between adsorption and regeneration in a short time, so it is easy to increase the amount of product generated per adsorbent. This has the advantage that the device can be easily made compact.

  As a method for removing trace impurities in the source gas, a temperature fluctuation adsorption separation (TSA) method is widely known. For example, in a cryogenic air separation device, a pretreatment device using a TSA method is used to remove water and carbon dioxide, which are trace components in raw material air. In this pretreatment device, impurities such as water and carbon dioxide, which are easily adsorbed components, are adsorbed and removed by passing air through an adsorbent packed bed of activated alumina or zeolite. The adsorbent that has reached adsorption saturation can be easily regenerated by circulating a heated purge gas.

In order to reuse the high value-added gas used in a semiconductor manufacturing apparatus or the like, it is necessary to remove unnecessary gas components such as trace impurities, reaction byproducts, and purge gas contained in the collected mixed gas. The removal of unnecessary gas components in the mixed gas can be achieved to some extent even by the combination of the above-described conventional techniques. For example, a trace gas component such as water, carbon dioxide, and ammonia can be adsorbed and removed by the TSA method using an adsorbent such as zeolite and activated alumina. In addition, a gas component containing a relatively large amount of nitrogen or the like can be selectively removed by a PSA method using a difference in equilibrium adsorption amount or adsorption rate of an adsorbent (see, for example, Patent Document 1).
JP 2002-126435 A

  However, it is difficult to remove helium and hydrogen by a combination of conventional techniques. That is, since helium and hydrogen have a property of being hardly adsorbed by the adsorbent, the TSA method for selectively adsorbing and removing easily adsorbed components cannot be applied. On the other hand, when the PSA method is used, helium and hydrogen, which are hard-to-adsorb components, can be concentrated on the product side, but in order to recover high value-added gas at a high recovery rate, high value added in exhaust gas is required. It is necessary to sufficiently reduce the gas concentration and increase the helium and hydrogen in the recovered gas to a sufficient gas concentration.

  In consideration of the apparatus cost and installation space, it is not realistic to increase a small amount of helium and hydrogen contained in the mixed gas to a predetermined concentration. In addition, as a method limited to hydrogen removal, a method may be considered in which water is adsorbed and removed by the TSA method or the like after injecting from the outside in a catalyst cylinder and reacting oxygen and hydrogen to change to water. However, in order to treat hydrogen, it is not only necessary to add a catalyst cylinder using a palladium catalyst or the like and an adsorption cylinder using the TSA method, but it is necessary to supply oxygen from outside the apparatus system. There was a problem of becoming complicated.

  As another separation method, it is conceivable to use a membrane separation method, but in any case, the configuration of the apparatus becomes complicated, resulting in an increase in apparatus cost and an increase in installation space.

  Therefore, the present invention provides a method for separating and refining high-value-added gas from exhaust gas discharged from manufacturing equipment for semiconductor products or display devices that use high-value-added gas such as krypton and xenon as an atmospheric gas. Gas separation method capable of efficiently removing trace gas components such as helium, hydrogen, etc. contained in the gas, and capable of continuously separating and refining a high value-added gas at a high recovery rate and reusing it, and The object is to provide a device.

  In order to achieve the above object, the gas separation method of the present invention has, as a first configuration, an impurity component in a mixed gas containing at least one high value-added gas of krypton, xenon, and neon by a pressure fluctuation adsorption separation method. A gas separation method for separating, wherein the mixed gas is introduced at a relatively high pressure from an inlet side of an adsorption cylinder filled with an adsorbent containing the high added value gas as an easily adsorbing component, and the high adsorbent is introduced into the adsorbent. An adsorption process for adsorbing the value-added gas and discharging the gas not adsorbed to the adsorbent from the outlet side of the adsorption cylinder, and reducing the pressure of the adsorption cylinder after the adsorption process to a relatively low pressure from the adsorbent In addition to desorbing the high value-added gas, a purge gas composed of the gas other than the high value-added gas and the impurity component in the mixed gas is introduced from the outside of the system to the outlet side of the adsorption cylinder, and the in-cylinder gas is introduced into the adsorption cylinder. A regeneration step of extruding and flowing out to the mouth side alternately, and regenerating exhaust gas flowing out from the inlet side of the adsorption cylinder in the first half of the regeneration process is circulated and mixed with the mixed gas, and in the latter half of the regeneration process, the adsorption cylinder It is characterized in that the regenerated exhaust gas flowing out from the inlet side is recovered as recovered gas. Furthermore, the gas separation method of the present invention is characterized in that, in the first configuration, the purge gas is at least one of oxygen, nitrogen and argon.

  According to a second configuration of the gas separation method of the present invention, the high-value-added gas is obtained by separating an impurity component in a mixed gas containing at least one high-value-added gas of krypton, xenon, and neon by a pressure fluctuation adsorption separation method. The gas separation method is for purifying the mixed gas at a relatively high pressure from the inlet side of the first adsorption cylinder filled with the first adsorbent containing the high added value gas in the mixed gas as an easily adsorbing component. A first adsorption step of introducing and adsorbing at least the high value-added gas to the first adsorbent, and discharging the gas flowing out from the outlet side of the first adsorption cylinder without adsorbing to the first adsorbent to the outside of the system Then, the in-cylinder gas of the first adsorption cylinder that has finished the first adsorption step is caused to flow out from the inlet side, the cylinder pressure is reduced to a relatively low pressure, and the gas adsorbed on the first adsorbent is desorbed. And from the outlet side of the first adsorption cylinder A first regeneration step of introducing one purge gas and pushing out the in-cylinder gas to the inlet side of the first adsorption cylinder and outflowing is alternately repeated in the first adsorption cylinder, and the first regeneration step is performed in the first half of the first regeneration process. A first separation process for circulating and mixing the first regenerated exhaust gas flowing out from the inlet side of the first adsorption cylinder into the mixed gas and recovering the first regenerated exhaust gas flowing out from the inlet side of the first adsorption cylinder in the second half of the first regeneration step. And the recovered gas recovered in the first separation process is filled with a second adsorbent containing the high added value gas as a hardly adsorbed component and a gas excluding the high added value gas in the recovered gas as an easily adsorbed component. Introduced at a relatively high pressure from the inlet side of the two adsorption cylinders, the second adsorbent adsorbs the gas excluding the high added value gas, and does not adsorb to the second adsorbent. The main component is high value-added gas that flows out from the outlet side. A second adsorption step for collecting gas; and the in-cylinder gas of the second adsorption cylinder that has completed the second adsorption process is caused to flow out from the inlet side, and the in-cylinder pressure is reduced to a relatively low pressure to thereby reduce the second adsorption. The gas adsorbed by the agent is desorbed, and the second purge gas consisting of a part of the gas mainly composed of the high added value gas collected in the second adsorption step is introduced from the outlet side of the second adsorption cylinder. A second regeneration step of extruding and flowing out the gas to the inlet side of the second adsorption cylinder is alternately repeated in the second adsorption cylinder, and the second regeneration step flows out from the inlet side of the second adsorption cylinder in the second regeneration step. A second separation process for circulating and mixing the regenerated exhaust gas into the mixed gas or the recovered gas, wherein the first purge gas is a gas excluding high value-added gas and impurity components in the mixed gas, and Gas that is an easily adsorbed component of the second adsorbent Is introduced from outside the system.

  The first configuration of the gas separation apparatus of the present invention is a gas separation apparatus that separates impurity components in a mixed gas containing at least one high value-added gas of krypton, xenon, and neon by a pressure fluctuation adsorption separation method. An adsorbing cylinder filled with an adsorbent containing the high value-added gas as an easily adsorbing component, and a mixed gas inlet path for introducing the mixed gas to the inlet side of the adsorbing cylinder through an inlet valve at a relatively high pressure An exhaust gas outlet path for discharging the gas flowing out from the outlet side of the adsorption cylinder through the outlet valve, and a purge gas composed of a gas excluding the high added value gas and the impurity component in the mixed gas through the purge valve A purge gas inlet path to be introduced on the outlet side of the gas generator, a regeneration gas outlet path for taking out the regeneration exhaust gas flowing out from the inlet side of the adsorption cylinder via the regeneration gas outlet valve, and the regeneration gas outlet path. A circulation path for circulating the regeneration gas through the circulation valve to the mixed gas inlet path and is characterized in that it comprises a recovery path for recovering the playback exhaust gas via a recovery valve.

  Furthermore, the second configuration of the gas separation apparatus according to the present invention is configured to separate the impurity component in the mixed gas containing at least one high value-added gas of krypton, xenon, and neon by a pressure fluctuation adsorption separation method, and thereby perform the high addition. A gas separation device for purifying a value gas, wherein a first adsorption cylinder filled with a first adsorbent having an easily adsorbed component as a high added value gas in the mixed gas, and a first adsorber cylinder on the inlet side of the first adsorption cylinder A mixed gas inlet path for introducing the mixed gas at a relatively high pressure via the inlet valve, an exhaust gas outlet path for discharging the gas flowing out from the outlet side of the first adsorption cylinder via the first outlet valve, A first purge gas inlet path for introducing a first purge gas to the outlet side of the first adsorption cylinder via the first purge valve; and a first regeneration exhaust gas flowing out from the inlet side of the first adsorption cylinder via the first regeneration gas outlet valve. The first regeneration gas A first circulation path for circulating the first regeneration exhaust gas taken out to the first regeneration gas outlet passage to the mixed gas supply means through the first circulation valve, and the first regeneration gas outlet passage to the first regeneration gas outlet passage A first separation part having a recovery path for recovering the first regenerated exhaust gas via a recovery valve; and the high added-value gas as a hardly adsorbed component, and in the recovered gas recovered in the recovery path of the first separation part A second adsorbing cylinder filled with a second adsorbent containing a gas other than the high value-added gas as an easily adsorbing component, and a relatively high pressure of the recovered gas on the inlet side of the second adsorbing cylinder via the second inlet valve The recovery gas inlet path to be introduced in step 2, the product outlet path for collecting the gas mainly composed of the high added-value gas flowing out from the outlet side of the second adsorption cylinder through the second outlet valve, and the product outlet path Made of a part of the gas mainly composed of high added value gas A second purge gas inlet path for introducing purge gas to the outlet side of the second adsorption cylinder via the second purge valve, and a second regeneration exhaust gas flowing out from the inlet side of the second adsorption cylinder via the second regeneration gas outlet valve A second regeneration gas outlet path to be taken out; and a second circulation path for circulating the second regeneration exhaust gas taken out to the second regeneration gas outlet path to the mixed gas supply means or the recovery path through a second circulation valve. The first purge gas inlet path includes a gas excluding the high value-added gas and the impurity component in the mixed gas and a gas that is an easily adsorbed component of the second adsorbent. It is characterized by a route introduced from outside the system.

  ADVANTAGE OF THE INVENTION According to this invention, trace gas components, such as helium and hydrogen, in the waste gas (mixed gas) containing the high added value gas discharged | emitted from the semiconductor manufacturing apparatus etc. can be removed very easily. Furthermore, since unnecessary gas components in the mixed gas can be discharged out of the system without impairing the high value-added gas, the high value-added gas can be continuously recovered at a high recovery rate.

  FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 shows a state in which one adsorption cylinder performs the adsorption process and the other adsorption cylinder performs the first half of the regeneration process. FIG. 2 is a system diagram showing the gas flow in bold lines, with one adsorption cylinder performing the adsorption process and the other adsorption cylinder performing the second half of the regeneration process. is there. In the figure, the black valve represents a closed state and the white valve represents an open state.

  The gas separation device shown in the present embodiment includes a mixed gas containing at least one high value-added gas of krypton, xenon, and neon, for example, an impurity component in exhaust gas discharged from a semiconductor product manufacturing facility. A plurality of adsorption cylinders 11A, 11B filled with an adsorbent containing gas as an easily adsorbing component are used, and the adsorption cylinders 11A, 11B are alternately switched between an adsorption process and a regeneration process by a pressure fluctuation adsorption separation method. Try to separate.

  In the adsorption cylinders 11A and 11B, mixed gas inlet paths 13A and 13B for introducing the mixed gas to the inlet sides (lower side in the drawing) of the adsorption cylinders 11A and 11B via the inlet valves 12A and 12B, and an adsorption process Exhaust gas outlet passages 15A and 15B for discharging gas flowing out from the outlet side (upper side in the figure) of the adsorption cylinders 11A and 11B through the outlet valves 14A and 14B, and the adsorption cylinders 11A and 11B during the regeneration process The purge gas inlet passages 17A and 17B for introducing the purge gas to the outlet side via the purge valves 16A and 16B, and the regeneration gas outlet valves 18A and 18B for the regeneration exhaust gas flowing out from the inlet side of the adsorption cylinders 11A and 11B during the regeneration process. And regenerative gas outlet paths 19A and 19B.

  In the mixed gas inlet paths 13A and 13B, a mixed gas introduction path 22 having a mixed gas storage tank 20 for storing the mixed gas and a compressor 21 for extracting the mixed gas in the mixed gas storage tank 20 and compressing it to a predetermined pressure. The mixed gas storage tank 20 is provided with an exhaust gas inflow path 23 through which exhaust gas discharged from the semiconductor product manufacturing facility flows.

  After the regeneration gas outlet paths 19A and 19B are combined into one path, the regeneration gas outlet paths 19A and 19B are branched into a circulation path 25 having a circulation valve 24 and a recovery path 27 having a recovery valve 26. The circulation path 25 is the mixed gas. Connected to the storage tank 20, the recovery path 27 is connected to a recovery gas storage tank 28 that stores the regenerated exhaust gas enriched in high added-value gas as recovery gas. The exhaust gas outlet paths 15 </ b> A and 15 </ b> B are combined into a gas exhaust path 30 including an exhaust control valve 29.

  The purge gas inlet passages 17A and 17B are connected to a purge gas supply source 33 via a purge gas introduction passage 32 having a purge gas introduction valve 31. The purge gas supply source 33 supplies a gas excluding the high value-added gas in the mixed gas and a trace impurity component to be removed. The supplied gas is usually compared with the mixed gas. A gas which is present in a large amount, that is, a gas corresponding to the main component of the mixed gas is selected.

  Specifically, when the mixed gas is a mixed gas of high value-added gas and argon and contains a trace amount to a small amount of hydrogen or helium, and other trace impurity components, argon is selected as the purge gas. When the mixed gas is a mixed gas of a high value-added gas, nitrogen, and a trace impurity component, it is optimal to select nitrogen as the purge gas. However, as the purge gas, an appropriate gas can be used as the purge gas according to the post-treatment of the high value-added gas concentrated gas recovered in the recovered gas storage tank 28, the purpose of use, the conditions of the usage destination, and the like.

  In particular, post-treatment of the high value-added gas concentrated gas recovered in the recovery gas storage tank 28 is performed by pressure fluctuation adsorption separation using an adsorbent having the high value-added gas as a hardly adsorbed component and the other gas components as easily adsorbed components. When the high value-added gas is purified to a high purity by the method, it is necessary to use a gas that can be separated from the high value-added gas by the pressure fluctuation adsorption separation method as the purge gas.

  Next, an example in which an exhaust gas discharged from a nitride film forming apparatus, which is one of semiconductor manufacturing apparatuses, is processed using the gas separation apparatus according to this embodiment will be described. The exhaust gas from the nitride film forming apparatus is a mixed gas containing xenon, which is a high value-added gas, and nitrogen used for ventilation in a chamber, a vacuum exhaust system, etc. as main components, and hydrogen as a trace impurity. Yes.

  First, it is preferable to use activated carbon which is an equilibrium separation type adsorbent as the adsorbent filled in the adsorption cylinders 11A and 11B. This activated carbon has the characteristics that the adsorption amount of xenon is large as an equilibrium adsorption amount (easy adsorption property), the adsorption amount of nitrogen is small (difficult adsorption property), and hardly adsorbs hydrogen. And is ideal for exhausting hydrogen and concentrating xenon. The purge gas supply source 33 uses high-purity nitrogen.

  The exhaust gas discharged from the semiconductor manufacturing apparatus flows into the mixed gas storage tank 20 through the exhaust gas inflow path 23, and is mixed with the regenerated exhaust gas circulating and flowing in from the circulation path 25 in the mixed gas storage tank 20. The fluctuation of the exhaust gas composition due to the change in the operating condition of the is reduced. The mixed gas in the mixed gas storage tank 20 is compressed to a predetermined pressure by the compressor 21, and then introduced into the adsorption cylinder 11A performing the adsorption process through the inlet valve 12A and the mixed gas inlet path 13A.

  Xenon in the mixed gas having a high pressure flowing into the adsorption cylinder 11A is adsorbed by the activated carbon filled in the cylinder and held in the cylinder, and nitrogen and hydrogen that have not been adsorbed on the activated carbon pass through the adsorption cylinder 11A. The gas flows out to the exhaust gas outlet path 15A and is discharged out of the system through the outlet valve 14A and the exhaust control valve 29 from the gas exhaust path 30. The adsorption step of the adsorption cylinder 11A is terminated before xenon flows out to the exhaust gas outlet passage 15A.

  While the adsorption cylinder 11A is performing the adsorption process, the other adsorption cylinder 11B is performing the regeneration process. This regeneration step is performed by opening the regeneration gas outlet valve 18B provided on the inlet side of the adsorption cylinder 11B and opening the purge valve 16B provided on the outlet side of the adsorption cylinder 11B. Further, in the first half of the regeneration process, as shown in FIG. 1, by opening the circulation valve 24, the in-cylinder gas flowing out from the inlet side of the adsorption cylinder 11B, that is, the regenerated exhaust gas is mixed gas storage tank through the circulation path 25. 20 to circulate.

  In the first half of this regeneration step, the regeneration gas outlet valve 18B and the circulation valve 24 are opened, whereby the high pressure adsorption cylinder 11B communicates with the low pressure mixed gas storage tank 20, and the gas in the adsorption cylinder 11B is regenerated gas outlet. The gas flows out from the path 19 </ b> B through the circulation path 25 to the mixed gas storage tank 20. Thereby, the inside of the adsorption cylinder 11B is depressurized, and part of the xenon and nitrogen adsorbed on the activated carbon in the adsorption process is desorbed from the activated carbon. The regeneration exhaust gas flowing out to the regeneration gas outlet path 19B in the first half of the regeneration process is desorbed from the mixed gas introduced into the adsorption cylinder 11B in the final stage of the adsorption process, that is, the mixed gas containing xenon, nitrogen and hydrogen, and activated carbon. A part of xenon and nitrogen and a part of purge nitrogen are mixed, and xenon is concentrated to some extent, but a gas in which hydrogen as a trace impurity remains.

  The mixed gas containing hydrogen is pushed out of the adsorption cylinder 11B by high purity nitrogen (hereinafter referred to as purge nitrogen) introduced into the adsorption cylinder 11B from the purge gas supply source 33 through the purge gas introduction path 32 and the purge gas inlet path 17B. 2, the circulation valve 24 is closed and the recovery valve 26 is opened, and the regenerated exhaust gas flowing out from the adsorption cylinder 11B to the regenerative gas outlet path 19B passes through the recovery path 27 as shown in FIG. Recover to 28.

  The in-cylinder gas flowing out into the regeneration gas outlet path 19B in the latter half of the regeneration process is in a state in which purge nitrogen is mixed with xenon desorbed from the activated carbon and a part of nitrogen, and hardly contains hydrogen. ing. Further, by introducing purge nitrogen, the desorption of xenon adsorbed on the activated carbon is promoted, and the regenerated exhaust gas recovered in the recovery gas storage tank 28 is in a state where xenon is concentrated. Purge nitrogen may be supplied from a high-pressure cylinder. If there is a high-purity nitrogen source or equipment used near the installation location of the gas separator, supply high-purity nitrogen branched from these. You can also.

  The opening and closing of the first half and second half of the regeneration process is performed in a preset time, and the recovery of the regenerated exhaust gas from the adsorption cylinder 11B to the recovered gas storage tank 28 after the switching is completed after the regeneration process is completed. It continues until it is switched to.

  When a predetermined process switching time elapses, the adsorption cylinder 11A is switched to the regeneration process and the adsorption cylinder 11B is switched to the adsorption process by opening / closing the valves. By alternately switching between the adsorption process and the regeneration process in both adsorption cylinders 11A and 11B, the separation and discharge of hydrogen and the concentration of xenon can be performed continuously.

  In this way, the adsorption process is performed using activated carbon, which is easier to adsorb xenon than nitrogen and hardly adsorbs hydrogen, thereby discharging hydrogen, which is a trace impurity in the mixed gas, while adsorbing the entire amount of xenon. As it is removed, most of the nitrogen can also be discharged.

 On the other hand, in the first half of the regeneration process, xenon is adsorbed again without being discharged out of the system by circulating the regenerated exhaust gas in which hydrogen remains in the mixed gas storage tank 20 provided on the mixed gas inlet path 13A, 13B side. Since it can be processed, the xenon recovery rate can be improved. Then, in the latter half of the regeneration process, the recovered exhaust gas that is almost free of hydrogen is recovered in the recovery gas storage tank 28, thereby obtaining a gas in which xenon is concentrated by removing hydrogen as a trace impurity. it can.

  In this embodiment as well, the operating cost of the compressor 21 can be reduced by adopting a pressure equalization process generally performed in the two-cylinder PSA.

  FIGS. 3 and 4 show a second embodiment of the present invention. FIG. 3 shows that a high pressure can be obtained by using two sets of pressure fluctuation adsorption devices of the first separator 10 and the second separator 50. It is a systematic diagram showing an example of a gas separation device that removes trace impurities from a mixed gas containing a value-added gas and separates gas components other than the value-added gas to purify the value-added gas with high purity.

 The first separation unit 10 that performs the first separation process in the previous stage uses the same configuration as the gas separation device shown in the first embodiment and can be operated in the same process. Each component in the separation unit 10 is assigned the same reference numeral as that of the gas separation device shown in the first embodiment, and detailed description thereof is omitted. Further, regarding the components having the same names in the first separation unit 10 and the second separation unit 50, “first” is included in the components included in the first separation unit 10, and the configuration included in the second separation unit 50. Each element is given a “second”.

 FIG. 4 is a system diagram showing a gas flow with a thick line when one adsorption cylinder in the second separation unit 50 performs an adsorption process and the other adsorption cylinder performs a regeneration process.

  The second separation unit 50 uses the high added value gas in the gas (recovered gas) collected from the collection path 27 of the first separation unit 10 in the collected gas storage tank 28 as a hardly adsorbed component and removes the high added value gas. The high-value-added gas is separated and purified by operating the plurality of second adsorption cylinders 51A and 51B filled with the second adsorbent containing the above gas as an easily adsorbing component alternately between the adsorption process and the regeneration process. I am doing so.

  The second adsorption cylinders 51A and 51B include recovery gas inlet paths 53A and 53B for introducing the recovery gas to the inlet sides of the second adsorption cylinders 51A and 51B via the second inlet valves 52A and 52B, and a second adsorption. Product outlet paths 55A and 55B for collecting high value added gas flowing out from the outlet sides of the cylinders 51A and 51B through the second outlet valves 54A and 54B, and a second purge valve on the outlet side of the second adsorption cylinders 51A and 51B The second purge gas inlet passages 57A and 57B for introducing the second purge gas through 56A and 56B and the regeneration exhaust gas flowing out from the inlet side of the second adsorption cylinders 51A and 51B are routed through the second regeneration gas outlet valves 58A and 58B. Second regeneration gas outlet paths 59A and 59B to be taken out are provided.

  The recovery gas inlet passages 53A and 53B are provided with a recovery gas introduction passage 61 having a second compressor 60 for extracting the recovery gas in the recovery gas storage tank 28 and compressing the recovery gas to a predetermined pressure. , 55B are connected to a product storage tank 63 via a product collection path 62. A product supply path 65 having a product supply valve 64 is provided in the product storage tank 63, and a part of the high added value gas in the product storage tank 63 is used as the second purge gas in the second purge gas inlet paths 57A and 57B. In order to supply, a second purge gas introduction path 67 having a second purge gas introduction valve 66 is provided.

  The second regeneration gas outlet paths 59 </ b> A and 59 </ b> B join a second circulation path 69 provided with a second circulation valve 68 and are connected to the mixed gas storage tank 20. This second circulation path 69 may be connected to the recovered gas storage tank 28 via the second recovery valve 70 as shown by a broken line in FIG. 3. Either of the mixed gas storage tank 20 and the recovered gas storage tank 28 may be connected. It is also possible to select and circulate.

  Next, using the gas separation apparatus shown in the present embodiment, the composition of the exhaust gas discharged from the semiconductor manufacturing apparatus is the same as in the first embodiment, and xenon, which is a high value-added gas, and ventilation or vacuum in the chamber. The first separation process in the first separation unit 10 and the second separation process in the second separation unit 50 are mixed gas containing, as a main component, nitrogen used in the exhaust system or the like and hydrogen as a trace impurity. An example in which xenon is separated and purified by treatment with a combination of these will be described.

  As the second adsorbent filled in the second adsorption cylinders 51A and 51B, it is preferable to use zeolite 4A (Na-A type zeolite) which is a speed separation type adsorbent. This zeolite 4A has the characteristics that it is difficult to adsorb xenon having a relatively large molecular diameter (hard adsorption) and that nitrogen having a molecular diameter smaller than that of xenon is easily adsorbed (easy adsorption). This characteristic is a separation characteristic generally referred to as a speed separation type. If an appropriate adsorption time is selected, it is possible to selectively adsorb nitrogen and not adsorb xenon.

  As shown in FIG. 4, the recovered gas recovered in the recovered gas storage tank 28 in the first separation process in the first separation unit 10 is compressed to a predetermined pressure by the second compressor 60, and then the second inlet valve 52A. And the second adsorption cylinder 51A performing the adsorption process through the recovered gas inlet path 53A. The nitrogen in the recovered gas having a high pressure flowing into the second adsorption cylinder 51A is adsorbed by the zeolite 4A filled in the cylinder and held in the cylinder, and the xenon not adsorbed on the zeolite 4A is absorbed in the second adsorption cylinder 51A. And flows out into the product outlet path 55A and is collected in the product storage tank 63 through the second outlet valve 54A and the product collection path 62.

 The high-purity xenon collected in the product storage tank 63 is supplied to a use destination such as a semiconductor manufacturing apparatus through a product supply valve 64 and a product supply path 65. The adsorption process of the second adsorption cylinder 51A is terminated before nitrogen flows out to the product outlet path 55A.

  While the second adsorption cylinder 51A is performing the adsorption process, the other second adsorption cylinder 51B is performing the regeneration process. In this regeneration step, the second regeneration gas outlet valve 58B provided on the inlet side of the second adsorption cylinder 51B is opened and the second purge valve 56B provided on the outlet side of the second adsorption cylinder 51B is opened. Is done by.

  In this regeneration step, since the second regeneration gas outlet valve 58B and the second circulation valve 68 are opened, the second adsorption cylinder 51B having a high pressure is in communication with the mixed gas storage tank 20 having a low pressure. The gas in the adsorption cylinder 51B flows out from the second regeneration gas outlet path 59B to the mixed gas storage tank 20 through the second circulation path 69. Thereby, the inside of the second adsorption cylinder 51B is depressurized, and part of nitrogen and xenon adsorbed on the zeolite 4A in the adsorption process is desorbed from the zeolite 4A.

  Further, the high added value gas introduced from the outlet side of the second adsorption cylinder 51B through the second purge gas introduction valve 66, the purge gas introduction path 67, the second purge valve 56B, and the second purge gas inlet path 57B from the product storage tank 63, The desorption of nitrogen from the zeolite 4A is promoted, and the desorbed nitrogen is pushed out from the inlet side of the second adsorption cylinder 51B toward the second regeneration gas outlet path 59B to purge the inside of the cylinder.

  Also in the regeneration process of the second separation unit 50, the regeneration exhaust gas having a relatively high nitrogen concentration flowing out to the second regeneration gas outlet path 59B is circulated in the mixed gas storage tank 20 in the first half of the regeneration process, and the second in the first half of the regeneration process. A process may be used in which the regeneration exhaust gas having a high xenon concentration flowing out to the regeneration gas outlet path 59B is circulated to the recovered gas storage tank 28. Moreover, the pressure equalization process currently performed with 2 cylinder type PSA is employable also in the 2nd separation part 50.

  In this way, the first adsorption cylinders 11A and 11B of the first separation unit 10 are filled with the first adsorbent (activated carbon) having the high added value gas (xenon) as an easily adsorbed component, and the first separation unit 10 In the adsorption process in the first separation process, trace impurities (hydrogen) are separated and removed, and in the regeneration process, the first purge gas (purge nitrogen) is introduced from outside the system so A gas enriched in the added value gas (xenon) is recovered, and then the second adsorbent (zeolite 4A) containing the high added value gas (xenon) as a hardly adsorbed component in the second adsorption cylinders 51A and 51B of the second separation unit 50. ), And the high-added-value gas (xenon) is separated and purified with high purity in the adsorption step in the second separation process in the second separation unit 50, and flows out from the second adsorption cylinder in the regeneration step. Regeneration By circulating the gas mixture or recovering the gases, without compromising the high value gas (xenon), it may be recovered and reused in a high yield and high purity.

  That is, when xenon is recovered from a mixed gas of xenon, nitrogen, and hydrogen at a high recovery rate, and high-purity xenon that does not contain nitrogen and hydrogen is collected, hydrogen is compared with gas components such as nitrogen and xenon. It has the property of being hardly adsorbed by the adsorbent. For this reason, when the mixed gas is introduced into the first adsorption cylinders 11A and 11B, hydrogen is not adsorbed by the adsorbent but passes through the adsorbent packed bed and is discharged from the outlet side of the first adsorption cylinder.

  Therefore, in the adsorption step, when a certain amount of gas is flowed out from the outlet side of the first adsorption cylinder, a large amount of hydrogen is contained in the outflow gas. Activated carbon has a property of being hardly adsorbed to nitrogen and easily adsorbed to xenon. For this reason, since xenon is adsorbed and held by the activated carbon, the main component of the gas flowing out from the first adsorption cylinder is nitrogen. Thereby, in the first separation process of the first separation unit 10, nitrogen and hydrogen can be selectively discharged out of the apparatus system without losing xenon.

  In a general pressure fluctuation adsorption separation method, in the regeneration step, a part of product gas is introduced as a purge gas from the adsorption cylinder outlet side in order to promote regeneration of the adsorbent. In this embodiment, a part of the gas mainly containing nitrogen flowing out from the first adsorption cylinder is used as the purge gas, and the gas mainly containing nitrogen is caused to flow into the first adsorption cylinder in the regeneration process. Can promote the desorption of xenon.

  However, in this embodiment, the gas flowing out from the outlet side of the first adsorption cylinder in the adsorption process contains not only nitrogen but also a lot of hydrogen. The use of nitrogen containing hydrogen as the purge gas does not particularly hinder the purpose of promoting the regeneration of the first adsorbent, but in the gas flowing out from the inlet side of the first adsorption cylinder in the regeneration process. There will always be a mixture of hydrogen.

  FIG. 5 shows the result of continuously measuring the hydrogen concentration contained in the regenerated exhaust gas flowing out from the inlet side of the first adsorption cylinder in the regeneration process. Case 1 is the first adsorption in the adsorption process. This is a measurement result when the gas flowing out from the cylinder is used as the purge gas, and Case 2 is a measurement result when high-purity nitrogen is used as the purge gas as described above.

  As is apparent from FIG. 5, in Case 1, hydrogen is always detected in the regeneration exhaust gas flowing out from the inlet side of the first adsorption cylinder in the regeneration process. On the other hand, in Case 2, sufficiently high-purity nitrogen is introduced as a purge gas from outside the system, and hydrogen is not contained in the purge gas. Therefore, the regeneration exhaust gas flowing out from the inlet side of the first adsorption cylinder in the regeneration process Only the hydrogen remaining in the voids of the adsorbent is contained.

  Compared to nitrogen and xenon that are adsorbed to a large amount by the first adsorbent, the amount of hydrogen remaining in the adsorbent voids is very small, so the hydrogen is concentrated by 100 seconds after the start of the regeneration process. It flows out and is not included in the regenerated exhaust gas after that. That is, the regenerated exhaust gas that flows out from the inlet side of the first adsorption cylinder in the regeneration process can be recovered by dividing the lead-out destination into the first half and the second half, and recovering the mixed gas enriched with xenon without containing hydrogen. .

  In this embodiment, the initial gas containing hydrogen is circulated to the mixed gas storage tank 20 upstream of the first adsorption cylinder, and the recovered gas storage downstream of the first adsorption cylinder is stored in the latter half of the gas not containing hydrogen. By leading to the tank 28, the mixed gas not containing hydrogen can be recovered and stored in the recovered gas storage tank 28.

There is an optimum range for the flow rate of the purge gas introduced from outside the system. That is, if the purge gas flow rate is small, hydrogen removal is insufficient, and if the purge gas flow rate is high, the exhaust gas flow rate is increased, resulting in a large loss of xenon. The flow rate of the purge gas is preferably a space velocity of 0.2 to 2 min ⁻¹ , more preferably 0.5 to 1.2 min ⁻¹ .

  The recovered gas composed of a mixed gas of xenon and nitrogen stored in the recovered gas storage tank 28 is easily adsorbed with respect to nitrogen and filled with a second adsorbent that is hardly adsorbed with respect to xenon. It is introduced into the suction cylinders 51A and 51B. In the adsorption step of the second adsorption cylinder, nitrogen in the mixed gas is adsorbed and held by the second adsorbent, so that high purity xenon can be collected in the product storage tank 63. The xenon stored in the product storage tank 63 is supplied as a product to a semiconductor manufacturing apparatus or the like.

  If it is necessary to further reduce the xenon impurity concentration for semiconductor manufacturing reasons, a purifier can be provided at the subsequent stage of the gas separation apparatus of the present invention. As this refining device, a getter type purifier using a metal or alloy such as titanium, vanadium, zirconium, iron, nickel or the like is suitable.

  The regeneration of the second adsorbent is performed using part of the product gas (xenon) stored in the product storage tank 63. By introducing xenon in the product storage tank 63 as a purge gas, desorption of nitrogen adsorbed on the second adsorbent can be promoted. The gas flowing out from the inlet side of the second adsorption cylinder in the regeneration process is returned to the mixed gas storage tank 20 or the recovered gas storage tank 28 again. By returning an appropriate amount of the outflow gas to the mixed gas storage tank 20, it is possible to prevent an excessive increase in the nitrogen concentration of the recovered gas stored in the recovered gas storage tank 28.

  As described above, in this embodiment, since hydrogen can be exhausted with nitrogen not containing xenon, loss of xenon can be minimized. Moreover, xenon in which hydrogen is not mixed can be produced by introducing purge nitrogen from the outside.

  In this embodiment, the gas separation apparatus is applied to the nitride film forming apparatus, and the conditions for recovering the mixed gas of xenon, nitrogen, and hydrogen are exemplified. However, the present invention can be widely applied in addition to those described here. . For example, in the case of an oxynitride film forming apparatus, oxygen is also mixed in addition to xenon, nitrogen, and hydrogen. In this case, oxygen flowing into the first adsorption cylinder is discharged together with nitrogen, and oxygen in the recovered gas can be adsorbed and removed by the second adsorption cylinder in the same manner as nitrogen.

Further, when ammonia or a nitric oxide compound is added to the nitride film or oxynitride film forming apparatus, it can be dealt with by installing a pretreatment apparatus using the TSA method or the like in the previous stage of the gas separation apparatus. The oxide film etching apparatus can be dealt with by installing a reaction adsorption apparatus for removing PFC, SIF _{4 and the} like as a pretreatment apparatus in the preceding stage of the gas separation apparatus. Further, even when krypton or neon other than xenon is included as the high value-added gas, separation of impurity components and separation / purification of the high value-added gas can be performed in the same manner.

  In the above-described embodiment, an example in which nitrogen is used as the first purge gas of the first separation unit 10 introduced from the outside of the apparatus is not particularly limited to nitrogen. Impurity components to be removed such as hydrogen and helium are not limited to nitrogen. If the gas is not included, the same effect as described above can be expected.

  For example, even when oxygen is used as the first purge gas in the embodiment, the gas from which hydrogen has been removed can be recovered in the recovery gas storage tank 28. In this case, oxygen is mixed into the recovered gas storage tank 28. However, since oxygen can be removed by the second separation unit 50 in the same manner as nitrogen, it does not hinder the separation and purification of xenon.

  Therefore, it is preferable to select the same gas component as the purge gas used in the vacuum exhaust means of the semiconductor manufacturing apparatus or the like, but the gas selected as the first purge gas of the first separation unit 10 is the second separation unit in the subsequent stage. Any gas can be selected as long as it can be easily removed at 50.

  The xenon circulation supply apparatus shown in FIG. 3 was manufactured, and an experiment for separating and purifying xenon from a mixed gas containing xenon was conducted. The flow rate of the mixed gas is 2.5 L / min (the flow rate [L / min] is 0 ° C., converted value of 1 atm, the same applies hereinafter), and the gas composition is 34% by volume of xenon, 64% by volume of nitrogen, 2 hydrogen. It is volume%. The volume of the mixed gas storage tank 20 was 100 L, and the first adsorption cylinders 11A and 11B were used in which 2.5 kg of activated carbon was packed in a cylindrical container having an inner diameter of 110.1 mm and a filling height of 600 mm.

  The volume of the recovered gas storage tank 28 was 50 L, and the second adsorption cylinders 51A and 51B were prepared by filling 7.4 kg of zeolite 4A in a cylindrical container having an inner diameter of 134.2 mm and a filling height of 600 mm. . The volume of the product storage tank 63 was 20L. The first compressor 21 has a capacity of about 40 L / min, and the second compressor 60 has a capacity of about 20 L / min.

  Nitrogen and xenon were sealed in advance to stabilize the gas concentration and pressure in the separation system, and the mixed gas was introduced into the mixed gas storage tank 20 from the exhaust gas inflow path 23. The first separation unit 10 and the second separation unit 50 have an operation time of one cycle of 500 seconds (250 seconds for both the adsorption process and the regeneration process), and switching between the first half and the second half of the regeneration process is 125 seconds after the start of the regeneration process. It was.

  In the adsorption step in the first separation unit 10, the mixed gas in the mixed gas storage tank 20 is pressurized by the first compressor 21 and introduced into the first adsorption cylinder 11 </ b> A. In the mixed gas introduced into the first adsorption cylinder 11A, xenon was adsorbed and held by the first adsorbent (activated carbon), and nitrogen and hydrogen flowed out from the adsorption cylinder outlet side to the exhaust gas outlet path 15A. The flow rate of the gas flowing out to the exhaust gas outlet path 15A was controlled to 6.45 L / min by the exhaust control valve 29 having a flow rate adjusting function. The pressure in the first adsorption cylinder was operated at atmospheric pressure to 500 kPa (gauge pressure).

  In the regeneration step in the first separation unit 10, 4.8 L / min of high-purity nitrogen is introduced as the first purge gas from the purge gas supply source 33 outside the apparatus, and is circulated to the first adsorption cylinder 15B through the first purge gas inlet path 17B. . The gas flowing out from the first adsorption cylinder 15B to the first regeneration gas outlet path 19B is led to the mixed gas storage tank 20 or the recovery gas storage tank 28 by switching the switching valve 24 and the recovery valve 26 in a predetermined time. Is done.

  Here, first, the gas that flowed out to the first regeneration gas outlet path 19B was circulated and returned to the mixed gas storage tank 20 by opening the circulation valve 24 and closing the recovery valve 26. After 125 seconds had elapsed, the circulation valve 24 was closed and the recovery valve 26 was opened, so that the outlet of the outflow gas was switched from the mixed gas storage tank 20 to the recovery gas storage tank 28. The return of the outflow gas to the recovered gas storage tank 28 was continued until the end of the regeneration process.

  On the other hand, in the adsorption process in the second separation unit 50, the recovered gas from the recovered gas storage tank 28 is pressurized by the second compressor 5 and introduced into the second adsorption cylinder 51A. In the recovered gas introduced into the second adsorption cylinder 51A, nitrogen is adsorbed and held in the second adsorbent (zeolite 4A), and xenon is collected in the product storage tank 63 through the product outlet path 55A and the product collection path 62.

  The flow rate of xenon stored in the product storage tank 63 was controlled to 0.85 L / min with a product supply valve 64 having a flow rate control function, and supplied to the user through the product supply path 65. The pressure in the second adsorption cylinder was operated at atmospheric pressure to 400 kPa.

  In the regeneration process in the second separation unit 50, the xenon stored in the product storage tank 63 was circulated to the second adsorption cylinder 51B as the second purge gas through the purge gas introduction path 67 and the second purge gas inlet path 57B. The gas flowing out from the second adsorption cylinder 51B to the second regeneration gas outlet path 59B was circulated and returned to the mixed gas storage tank 20 and the recovered gas storage tank 28 through the second circulation path 69. Here, after starting the regeneration process, the gas is first circulated in the mixed gas storage tank 20 and is circulated in the recovered gas storage tank 28 after 10 seconds. Circulation to the recovered gas storage tank 28 continued until the regeneration step.

  When the gas separator is continuously operated in the above process while the first adsorption cylinders 11A, 11B and the second adsorption cylinders 51A, 51B are alternately switched between the adsorption process and the regeneration process, the mixed gas discharged from the first compressor 21 It was confirmed that the concentration of xenon was 58 to 62% by volume and settled to a steady state of circulation. At this time, the concentration of impurities contained in the nitrogen exhausted from the gas exhaust path 30 is about 90 ppm for xenon and about 8000 ppm for hydrogen, and the concentration of impurities contained in xenon obtained from the product supply path 65 is the concentration of nitrogen. Was about 50 ppm, and the hydrogen concentration was 4 ppm.

  As described above, it was confirmed that xenon, which is a high value-added gas, can be separated and purified from a mixed gas of xenon and nitrogen containing a trace amount of hydrogen. When the impurity concentration required for semiconductor manufacturing or the like is severe, the impurity concentration can be reduced to less than 0.1 ppm by attaching a getter purifier after the gas separator. The effective loss amount of xenon in this example was 90 ppm × 6.45 L / min = 0.58 cc / min, and the xenon recovery rate was 99.93%.

The 1st example of this invention is shown and it is a systematic diagram which shows the flow of a gas when the one adsorption cylinder is performing the adsorption | suction process and the other adsorption cylinder is performing the first half of the reproduction | regeneration process with a thick line. . Similarly, it is a system diagram which shows a gas flow when one adsorption cylinder is performing the adsorption process and the other adsorption cylinder is performing the second half of the regeneration process with a bold line. The 2nd example of this invention is shown and it is a systematic diagram which shows an example of the gas separation apparatus which combined two sets of pressure fluctuation adsorption apparatuses of the 1st separation part and the 2nd separation part. It is a systematic diagram which shows the flow of gas when the one adsorption cylinder in the 2nd separation part is performing the adsorption process, and the other adsorption cylinder is performing the regeneration process by a thick line. It is a figure which shows the result of having continuously measured the hydrogen concentration contained in the gas which flows out from the inlet side of the 1st adsorption cylinder in a regeneration process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... 1st separation part, 11A, 11B ... (1st) Adsorption cylinder, 12A, 12B ... (1st) Inlet valve, 13A, 13B ... Mixed gas inlet path, 14A, 14B ... (1st) Outlet valve, 15A , 15B ... exhaust gas outlet passage, 16A, 16B ... (first) purge valve, 17A, 17B ... (first) purge gas inlet passage, 18A, 18B ... (first) regeneration gas outlet valve, 19A, 19B ... (first) ) Regeneration gas outlet path, 20 ... mixed gas storage tank, 21 ... (first) compressor, 22 ... mixed gas introduction path, 23 ... exhaust gas inflow path, 24 ... circulation valve, 25 ... circulation path, 26 ... recovery valve, 27 ... Recovery path, 28 ... Recovery gas storage tank, 29 ... Exhaust control valve, 30 ... Gas exhaust path, 31 ... (First) purge gas introduction valve, 32 ... (First) purge gas introduction path, 33 ... Purge gas supply source, 50 ... 2nd separation part, 51A, 1B ... second adsorption cylinder, 52A, 52B ... second inlet valve, 53A, 53B ... recovered gas inlet path, 54A, 54B ... second outlet valve, 55A, 55B ... product outlet path, 56A, 56B ... second purge valve 57A, 57B ... second purge gas inlet path, 58A, 58B ... second regeneration gas outlet valve, 59A, 59B ... second regeneration gas outlet path, 60 ... second compressor, 61 ... recovered gas introduction path, 62 ... product Sampling path, 63 ... Product storage tank, 64 ... Product supply valve, 65 ... Product supply path, 66 ... Second purge gas introduction valve, 67 ... Second purge gas introduction path, 68 ... Second circulation valve, 69 ... Second circulation path 70 ... second recovery valve

Claims (5)

  A gas separation method for separating an impurity component in a mixed gas containing at least one kind of high value-added gas of krypton, xenon, and neon by a pressure fluctuation adsorption separation method, wherein the high value-added gas is used as an easily adsorbed component. The mixed gas is introduced at a relatively high pressure from the inlet side of the adsorption cylinder filled with the adsorbent to adsorb the high value-added gas to the adsorbent and the gas not adsorbed to the adsorbent to the outlet side of the adsorption cylinder The adsorption process for discharging the gas, and desorbing the high value-added gas from the adsorbent by depressurizing the adsorption cylinder having completed the adsorption process to a relatively low pressure, and the high value-added gas and impurity components in the mixed gas A regeneration process of introducing a purge gas composed of a gas excluding gas from the outside of the system to the outlet side of the adsorption cylinder and extruding the in-cylinder gas toward the inlet side of the adsorption cylinder is alternately repeated. The regeneration exhaust gas flowing out from the inlet side of the adsorption cylinder in the first half of the process is circulated and mixed with the mixed gas, and the regeneration exhaust gas flowing out from the inlet side of the adsorption cylinder in the second half of the regeneration process is recovered as a recovery gas. Gas separation method.   The gas separation method according to claim 1, wherein the purge gas is at least one of oxygen, nitrogen, and argon.   A gas separation method for purifying the high value-added gas by separating an impurity component in the gas mixture containing at least one kind of high value-added gas of krypton, xenon and neon by a pressure fluctuation adsorption separation method. The mixed gas is introduced at a relatively high pressure from the inlet side of the first adsorption cylinder filled with the first adsorbent containing the high added value gas as an easily adsorbing component, and at least the high added value is added to the first adsorbent. A first adsorption step for adsorbing a gas and discharging the gas flowing out from the outlet side of the first adsorption cylinder without being adsorbed to the first adsorbent; and the first adsorption after the completion of the first adsorption step In-cylinder gas of the cylinder is caused to flow out from the inlet side, the pressure in the cylinder is reduced to a relatively low pressure to desorb the gas adsorbed on the first adsorbent, and the first purge gas from the outlet side of the first adsorption cylinder In-cylinder gas is introduced The first regeneration step of pushing out and flowing out to the inlet side of the adsorption cylinder is alternately repeated in the first adsorption cylinder, and the first regeneration flowing out from the inlet side of the first adsorption cylinder in the first half of the first regeneration step A first separation process in which exhaust gas is circulated and mixed with the mixed gas, and the first regeneration exhaust gas flowing out from the inlet side of the first adsorption cylinder is collected in the latter half of the first regeneration step, and the recovered gas recovered in the first separation process Is a relatively high pressure from the inlet side of the second adsorption cylinder filled with the second adsorbent containing the high added value gas as a hardly adsorbed component and the gas excluding the high added value gas in the recovered gas as an easily adsorbed component. And the second adsorbent adsorbs the gas excluding the high added value gas, and the high added value gas that has flowed out from the outlet side of the second adsorption cylinder without being adsorbed by the second adsorbent is a main component. A second adsorption step for collecting the gas The in-cylinder gas of the second adsorption cylinder that has finished the adsorption step is caused to flow out from the inlet side, the pressure in the cylinder is reduced to a relatively low pressure to desorb the gas adsorbed on the second adsorbent, and the second adsorption A second purge gas comprising a part of a gas mainly composed of the high added value gas collected in the second adsorption step is introduced from the outlet side of the cylinder, and the in-cylinder gas is pushed out to the inlet side of the second adsorption cylinder and flows out. The second regeneration step is performed alternately and repeatedly in the second adsorption cylinder, and the second regeneration exhaust gas flowing out from the inlet side of the second adsorption cylinder in the second regeneration step is circulated to the mixed gas or the recovered gas. A second separation process for mixing, wherein the first purge gas is a gas excluding a high value-added gas and an impurity component in the mixed gas, and a gas that is an easily adsorbed component of the second adsorbent. Gus characterized by being introduced from outside the system Separation method.   A gas separation device for separating impurity components in a mixed gas containing at least one kind of high value-added gas of krypton, xenon and neon by a pressure fluctuation adsorption separation method, and using the high value-added gas as an easy-adsorption component An adsorbing cylinder filled with an agent, a mixed gas inlet path for introducing the mixed gas at a relatively high pressure to the inlet side of the adsorbing cylinder through an inlet valve, and an outlet valve for the gas flowing out from the outlet side of the adsorbing cylinder An exhaust gas outlet path for discharging the exhaust gas, a purge gas inlet path for introducing a purge gas made of a gas excluding the high added value gas and the impurity component in the mixed gas to the outlet side of the adsorption cylinder through the purge valve, and an inlet of the adsorption cylinder A regeneration gas outlet path for taking out the regeneration exhaust gas flowing out from the side through the regeneration gas outlet valve, and a circulation valve for the regeneration exhaust gas taken out to the regeneration gas outlet path in the mixed gas inlet path Gas separation apparatus for a circulation path for circulating and, characterized by comprising a recovery path for recovering the regeneration exhaust gas via a recovery valve.   A gas separation device for purifying the high value-added gas by separating an impurity component in the gas mixture containing at least one kind of high value-added gas of krypton, xenon, and neon by a pressure fluctuation adsorption separation method. A first adsorbing cylinder filled with a first adsorbent containing a high value-added gas as an easily adsorbing component, and the mixed gas at a relatively high pressure via an inlet valve on the inlet side of the first adsorbing cylinder. The mixed gas inlet path to be introduced, the exhaust gas outlet path for discharging the gas flowing out from the outlet side of the first adsorption cylinder via the first outlet valve, and the first purge valve on the outlet side of the first adsorption cylinder via the first purge valve A first purge gas inlet path for introducing one purge gas, a first regeneration gas outlet path for taking out the first regeneration exhaust gas flowing out from the inlet side of the first adsorption cylinder via the first regeneration gas outlet valve, and the first regeneration gas First taken out to exit path A first circulation path for circulating the raw exhaust gas to the mixed gas supply means via the first circulation valve; and a recovery path for recovering the first regeneration exhaust gas taken out to the first regeneration gas outlet path via the recovery valve. The first separation unit provided, and the second adsorption having the high added value gas as a hardly adsorbed component and the gas excluding the high added value gas in the recovered gas collected in the recovery path of the first separator as an easily adsorbed component A second adsorption cylinder filled with an agent, a recovery gas inlet path for introducing the recovery gas to the inlet side of the second adsorption cylinder through a second inlet valve at a relatively high pressure, and an outlet side of the second adsorption cylinder A product outlet path for collecting a gas mainly composed of high value-added gas flowing out from the second outlet valve, and a part of the gas mainly composed of the high value added gas collected in the product outlet path. The second purge gas is discharged from the second adsorption cylinder through the second purge valve. A second purge gas inlet path to be introduced into the second adsorbing cylinder, a second regeneration gas outlet path for taking out the second regeneration exhaust gas flowing out from the inlet side of the second adsorption cylinder via the second regeneration gas outlet valve, and the second regeneration gas outlet path And a second separation section provided with a second circulation path for circulating the second regenerated exhaust gas taken out to the mixed gas supply means or the recovery path through a second circulation valve, and the first purge gas inlet path is A gas separation device characterized in that the gas is a gas from which high-value-added gas and impurity components in the mixed gas are removed, and is a path through which a gas that is an easily adsorbed component of the second adsorbent is introduced from outside the system. .

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