KR20100012692A - Membrane module for isolation of sulfur hexafluoride and apparatus for recovery of sulfur hexafluoride - Google Patents

Abstract

PURPOSE: A sulfur hexafluoride separation module and a sulfur hexafluoride recovery device using the same are provided to effectively recover SF6 by constituting a plurality of gas separation tubes with a material of which absorption of the SF6 is minimized. CONSTITUTION: A sulfur hexafluoride separation module includes a chamber(120) and a gas separation membrane(110) consisting of a plurality of gas separation tubes(111) and quipped inside the chamber. A plurality of gas discharge holes(112) is equipped on the surface of the gas separation tubes. The diameter of the gas discharge hole is smaller than the molecular diameter of the SF6. A sulfur hexafluoride recovery device includes a mixed gas supply tank, a mixed gas stabilization tank, an SF6 separation module, and a temperature maintaining device.

Description

Membrane module for isolation of sulfur hexafluoride and apparatus for recovery of sulfur hexafluoride

The invention SF ₆ separation membrane module and this, using SF ₆ recovered relates to a device, and more particularly do not require an additional process for the SF ₆ recovered with improving the recovery rate of SF ₆ SF ₆ separation membrane module and an SF using the same. ₆ relates to a recovery device.

SF ₆ is a representative electrical insulating material of power devices, and is used in cleaning processes in manufacturing semiconductor wafers and LCD panels. SF ₆ is known to have more than 23,900 times more impact on global warming than carbon dioxide, and was designated as one of the six largest global warming index materials at the Conference on Climate Change Convention in Kyoto in 1997. . Therefore, processing for SF ₆ is urgently required.

The processing method for the SF _6, there is a first method to decompose SF _6. Since SF ₆ is very stable, high energy such as plasma is required to decompose, and there is a disadvantage that high by-products such as S ₂ F ₁₀ , SF ₄ , and HF are generated during decomposition. If such problems with the decomposition considering the continuous price rise of SF ₆ by effectively recovering SF ₆ is highly desirable in terms of reducing production costs to promote reuse.

SF techniques for recovering ₆ has a technology for recovering only the mixed gas of SF ₆ with SF _6, naengbeop seam common gas separation corporation, PSA (pressure swing adsorption) method, a membrane separation method or the like can be applied.

First, the deep cooling method is suitable for large-capacity and high-concentration treatment, but requires a high investment cost and has a disadvantage of low energy consumption efficiency. Next, the PSA method, which is a technology of separating SF ₆ by adsorbing nitrogen having a small molecular size by using an adsorbent such as zeolite, alternately pressurization and depressurization, desorbs nitrogen adsorbed in the depressurization process and then pressurization process. Is a technology that separates mixed gas such as nitrogen / SF ₆ by adsorbing new nitrogen. In the PSA method, SF ₆ leaks during desorption, and a recovery rate of 90% or more can be obtained. However, when the concentration of SF ₆ is low in the mixed gas introduced into the system, the concentration of SF ₆ in the recovered gas is originally reduced. Only about 60vol% of the disadvantage that the additional liquefaction process after the separation process has a disadvantage.

The present invention is one made in view the above problems, with an additional process is not required SF ₆ separation membrane module and this for SF ₆ recovered with improving the recovery rate of SF ₆ SF ₆ aims to provide recovered jangchieul There is this.

SF ₆ separator module according to the present invention for achieving the above object comprises a chamber and a gas separation membrane provided in the chamber and composed of a plurality of gas separation tube, a plurality of gas discharge holes on the surface of the gas separation tube Characterized in that provided.

The diameter of the gas discharge hole is smaller than the molecular diameter of SF ₆ , it is preferable that the gas separation membrane and the inner wall of the chamber are spaced a predetermined distance. In addition, a fixing band for surrounding and fixing the gas separation membrane may be further provided at both ends of the gas separation membrane.

One end of the chamber is provided with a gas inlet through which a mixed gas including SF ₆ is introduced, and a first outlet for discharging SF ₆ is provided at the other end of the chamber, and one side of the chamber except for SF ₆ in the mixed gas. A second outlet for discharging the gas may be provided.

The gas separating tube is composed of SF ₆ absorption degree of the falling material in the mixed gas containing SF _6, polysulfone, carbon (carbon), polyimide (polyimide), polycarbonate (polycarbonate), polyesters (polyester ), Polyester carbonate (polyestercarbonate), polyester sulfone (polyestersulfone), polyamide (polyamide), it may be made of any one of polyphenylene (polyphenylene).

The plurality of gas separation tube is brought into close contact with each other form an assembly, the gas discharge hole must be larger than the molecular diameter of the gas other than the SF ₆ in a mixed gas comprising SF _6. In addition, a separator is further provided on both ends of the chamber, and the space between the gas separation membrane and the inner wall of the chamber is separated from the outside by the separator.

SF ₆ recovery apparatus according to the present invention is a mixed gas supply tank for storing a mixed gas containing SF ₆ and a mixed gas stabilization of the mixed gas supplied from the mixed gas supply tank to maintain a constant SF ₆ concentration in the mixed gas The SF ₆ membrane module and the SF ₆ membrane module for separating the tank and the mixed gas supplied from the mixed gas stabilization tank into SF ₆ and other gases, and while maintaining the temperature of the SF ₆ membrane module constant Characterized in that it comprises a constant temperature holding device that serves to make.

And a SF ₆ recovery tank and other gas recovery tanks for storing SF ₆ and other gases separated by the SF ₆ membrane module, respectively, and a concentration measuring device for measuring the concentration of SF _{6 in} the SF ₆ recovery tank. It may further include.

In addition, a temperature control device for controlling the temperature of the mixed gas stabilization tank may be further provided on one side of the mixed gas stabilization tank, remove impurities for filtering impurities contained in the mixed gas at the inlet end of the mixed gas stabilization tank. A filter may be further provided.

SF ₆ membrane module and the SF ₆ recovery device using the same according to the present invention has the following effects.

Of the gas separator tube with gas discharge holes and constituting the bundle in the form of a gas separation membrane other than the SF ₆ gas it will be able SF ₆ can be effectively recovered by separating through a gas discharge hole.

In addition, the discharge through the absorption of other gases other than the SF ₆ gas separated by forming the tube to minimize the degree of adsorption of the substance SF ₆ is allows it is possible to improve the recovery rate and the concentration of SF _6.

Hereinafter, with reference to the drawings will be described in detail the SF ₆ separator module and SF ₆ recovery apparatus using the same according to an embodiment of the present invention. 1 is a perspective view of an SF ₆ separation membrane module according to one embodiment of the invention, Figure 2 is a cross-sectional view of an SF ₆ separation membrane module according to one embodiment of the present invention.

First, as shown in FIGS. 1 and 2, the SF ₆ separator module according to an embodiment of the present invention includes a gas separator 110 including a plurality of gas separation tubes 111. The gas separator tube 111 is an example which serves as separating SF ₆ and other gases from the mixed gas containing the SF _6, may be implemented as a straw shape having a predetermined internal diameter and predetermined length. Such gas separation tubes 111 form an aggregate to form the gas separation membrane 110, and fixing bands 113 may be provided at both ends of the gas separation membrane 110 as an auxiliary means for forming the aggregation.

On the other hand, a plurality of gas discharge holes 112 are provided on the surface of the gas separation tube 111. The gas exhaust hole 112 is SF ₆ O _2, N _2, CO _2, such as a hole for discharging the gas, mixed gas of SF ₆ flow into the gas separation tube 111 is a gas separator tube (111), except for The gas continues to flow along the inner space, except for SF ₆ , and gases such as O ₂ , N ₂ , and CO ₂ are discharged to the outside through the gas discharge hole 112.

The principle of separating SF ₆ from other gases is primarily based on the difference in molecular diameters of SF ₆ and other gases. As shown in Table 1 below, the molecular diameter of SF ₆ is 5.02Å and the molecular diameter is much larger than that of O ₂ of 3.28Å and N _{2 of} 3.60Å. It is possible to separate SF ₆ and other gases. Based on this, the diameter of the gas discharge hole 112 is preferably designed to be larger than the molecular diameter of other gases, such as O ₂ , N ₂ , CO _2, etc. except SF ₆ , and smaller than the molecular diameter of SF ₆ . Do.

TABLE 1 Molecular diameters of O ₂ , N ₂ and SF ₆

O ₂ N ₂ SF ₆ Molecular diameter 3.28Å 3.60Å 5.02Å

In separating SF ₆ and other gases, the adsorption with the gas separation tube 111 should be considered in addition to the difference in molecular diameter. Except for SF ₆ , other gases such as O ₂ , N ₂ , and CO ₂ are discharged to the gas discharge holes 112 by designing the gas discharge holes 112 as described above to be larger than the molecular diameter of other gases. In addition to the method of physically discharging, other gases may also be discharged due to a difference in gas concentration in and out of the gas separation tube 111.

The method of discharging other gases due to the difference in gas concentration inside and outside the gas separation tube 111 means that other gases except SF ₆ are adsorbed on the inner wall of the gas separation tube 111 and the surface of the other gas becomes high. It refers to a method in which other gases move along the inner wall of the gas separation tube 111 due to the energy difference, and ultimately discharged through the gas discharge hole 112 having low surface energy. As such, in order for the other gas to move along the inner wall of the gas separation tube 111 to be discharged through the gas discharge hole 112, the other gas is relatively well adsorbed while SF ₆ is not well adsorbed. The gas separation tube 111 should be configured.

In an embodiment of the present invention, polysulfones are used as materials satisfying the adsorption conditions as described above, and the adsorption performance of the polysulfone is illustrated in FIG. 5. 5 is a graph showing the adsorption performance of SF ₆ , O ₂ , N ₂ , CO ₂ according to pressure under isothermal temperature of 303K. As shown in FIG. 5, SF ₆ is not adsorbed to polysulfone regardless of pressure. it can be seen, whereas O ₂ and N ₂ is the pressure below 1bar and absorption also is shown a close adsorption to 1000mol / m ₃ is also in accordance with the falling pressure rise, the case of CO ₂ compared to O ₂ and N ₂ superior It can be seen that the degree of adsorption.

In one embodiment of the present invention, polysulfone is presented as a material constituting the gas separation tube 111, but in addition to polysulfone, carbon, polyimide, polycarbonate, polyester ), Polyester carbonate (polyestercarbonate), polyester sulfone (polyestersulfone), polyamide (polyamide), polyphenylene (polyphenylene) can be composed of any one.

Meanwhile, the aggregate of the gas separation tubes 111, that is, the gas separation membrane 110 is provided in the chamber 120. The chamber 120 serves to isolate the gas separation membrane 110 from the external environment and provide a trapping space for other gases discharged from the gas discharge hole 112 of the gas separation tube 111. In detail, the chamber 120 includes a gas inlet 121, a first outlet 122, and a second outlet 123. The gas inlet 121 is where the mixed gas containing SF ₆ and O ₂ , N ₂ , CO _2, etc. is introduced, and the first outlet 122 is exactly one end of the chamber 120, the gas inlet. It is provided at the opposite point of the 121 and the SF ₆ is discharged, the second outlet 123 is a place where other gases such as O ₂ , N ₂ , CO ₂ is discharged, preferably, the chamber 120 Is provided on the side.

In addition, to ensure a space where other gases such as O ₂ , N ₂ , and CO ₂ discharged from the gas discharge holes 112 of the gas separation tubes 111 may stay before being discharged to the second outlet 123. The inner wall of the gas separation membrane 110 and the chamber 120 may be spaced a predetermined distance d to provide a predetermined space. At this time, the separation plate 124 at both ends of the chamber 120 to prevent the mixed gas flowing from the gas inlet 121 to flow directly into the space between the gas separation membrane 110 and the inner wall of the chamber 120. In addition, the fixing band 113, that is, the fixing band 113 provided at both ends of the gas separation membrane 110 is provided with the space between the gas separation membrane 110 and the inner wall of the chamber 120 and the mixed gas. It serves to isolate the incoming space.

In the above, the SF ₆ separator module according to an embodiment of the present invention has been described. Hereinafter, the SF ₆ recovery apparatus using the SF ₆ membrane module according to an embodiment of the present invention will be described. 3 is a block diagram of the SF ₆ recovery apparatus according to an embodiment of the present invention.

As shown in Figure 3 SF ₆ recovery apparatus according to an embodiment of the present invention is largely mixed gas supply tank 301, mixed gas stabilization tank 302, SF ₆ membrane module 304, thermostat, SF _{6 is} composed of a combination of the recovery tank 305, other gas recovery tank 306 and the concentration measuring device (307).

The mixed gas supply tank 301 is for supplying a mixed gas of SF ₆ gas and other gases such as O ₂ , N ₂ , CO ₂ ultimately to the SF ₆ membrane module 304, and is a power device or a semiconductor. It serves to store the mixed gas including SF ₆ generated in the cleaning process. At this time, the SF ₆ concentration in the mixed gas varies depending on the level of SF ₆ generation at the source, but is usually 5 to 15% at low concentrations and about 50% at high concentrations.

On the other hand, in the mixed gas supplied from the mixed gas supply tank 301, since the concentration of SF ₆ gas is not constant, it is necessary to keep the concentration of SF _{6 in the} mixed gas constant. To this end, a mixed gas stabilization tank 302 for stabilizing the mixed gas is provided. The mixed gas stabilization tank 302 receives the mixed gas containing SF ₆ from the mixed gas supply tank 301 to stabilize the mixed gas to maintain the concentration of the SF ₆ gas in a state in which the mixed gas is SF. ₆ serves to supply to the membrane module (304). Thus, the reason to constant, supplying the SF ₆ concentration in the mixed gas, SF _6, and in order to accurately grasp the processing efficiency and the recovery rate of SF ₆ of the membrane module 304, how constant the concentration of SF ₆ May be achieved by maintaining the mixed gas in the mixed gas stabilization tank for a predetermined time.

In addition, the SF ₆ concentration in the mixed gas may be selectively controlled by controlling the temperature of the mixed gas stabilization tank 302. For example, it is possible to increase the temperature in the mixed gas stabilization tank 302 through the temperature controller to lower the concentration of SF ₆ or, conversely, to lower the temperature to increase the concentration of SF ₆ . In addition, an impurity removal filter may be further provided at the inlet end of the mixed gas stabilization tank 302 to remove impurities such as water contained in the mixed gas.

The constant temperature holding device 303 serves to maintain a constant temperature of the SF ₆ membrane module 304 while providing a mounting space for the SF ₆ membrane module 304. Since the gas constant (R), and varies depending on the temperature, and thus the gas constant is changed when the SF of the SF ₆ separation membrane module _{(304) 6, O 2,} N 2, CO 2 , such as permeability changes in SF ₆ membrane module 304 should be maintained at a constant temperature. In addition, in consideration of the processing efficiency of the SF ₆ membrane module 304, the constant temperature holding device 303 is preferably adjusted within a temperature range of 20 ~ 150 ℃. On the other hand, the SF ₆ membrane module 304 provided in the thermostat 303 serves to separate the mixed gas into SF ₆ gas and other gas other than this, as an embodiment 1 and 2 It may be made as shown in the configuration, a detailed description thereof will be omitted.

Next, the SF ₆ recovery tank 305 serves to recover the SF ₆ gas separated from the mixed gas by the SF ₆ membrane module 304, and the other gas recovery tank 306 is the SF ₆ separator It serves to recover other gases except SF ₆ gas separated from the mixed gas by the module 304. The last time, as to the concentration measuring apparatus 307 is connected to the SF ₆ the recovery tank (305) measuring the SF ₆ concentration in the SF ₆ the recovery tank 305, etc. In detail, gas chromatography (gas chromatograph) Can be configured.

As described above, operations of the SF ₆ separator module 304 and the SF ₆ recovery device according to the exemplary embodiment of the present invention as described above are as follows. 4 is a flow chart for explaining the operation of the SF ₆ recovery apparatus according to an embodiment of the present invention.

First, as shown in FIG. 4, a mixed gas including SF ₆ generated during a power device or semiconductor cleaning process is stored in the mixed gas supply tank 301. Subsequently, the mixed gas in the mixed gas supply tank 301 is supplied to the mixed gas stabilization tank 302 and the concentration of SF ₆ in the mixed gas stabilization tank 302 is constant. At this time, the temperature of the mixed gas stabilization tank 302 may be adjusted to selectively control the SF ₆ concentration in the mixed gas.

Mixture to maintain a certain level of SF ₆ concentration of the gas is SF ₆ is fed to the membrane module (304), SF ₆ and proceeds the membrane module (304) SF ₆ with the exception of this, separated by other gases by. The separation process by the SF ₆ membrane module 304 is as follows.

When a mixed gas including SF ₆ and other gases such as O ₂ , N ₂ , and CO ₂ is supplied through the gas inlet 121 of the chamber 120, the mixed gas is introduced into each gas separation tube 111. do.

The mixed gas introduced into each gas separation tube 111 is moved along the gas separation tube 111. Other gases except SF ₆ are gas discharge holes 112 provided on the surface of the gas separation tube 111. Is discharged through, SF ₆ continues to move to one end of the gas separation tube (111). At this time, other gases such as O ₂ , N ₂ , CO _2, etc. are adsorbed on the inner wall of the gas separation tube 111 during the movement, and when the concentration of the adsorbed gas becomes large, the gas discharge hole is caused by the difference in surface energy. Move towards 112 and ultimately exit. That is, other gases such as O ₂ , N ₂ , CO ₂ is directly discharged to the gas discharge hole 112 having a larger diameter than itself, or is discharged by movement by adsorption and gas concentration difference.

Other gases such as O ₂ , N ₂ , and CO ₂ discharged through the gas discharge holes 112 of the gas separation tubes 111 may be finally formed through the space between the gas separation membrane 110 and the inner wall of the chamber 120. 2 is discharged through the outlet 123, the SF ₆ moved from one end of the gas separation tube 111 to the other end is discharged through the first outlet (122).

SF ₆ and other gases are separated by the SF ₆ membrane module 304, and the separated SF ₆ gas is transferred to the SF ₆ recovery tank 305, and other gases such as O ₂ , N ₂ , and CO ₂ are other. It is delivered to the gas recovery tank 306. Next, the operation of the SF ₆ and collecting apparatus according to an embodiment of the present when using the concentration measuring apparatus 307 measuring the SF ₆ SF ₆ concentration in the recovery tank 305. invention is completed.

On the other hand, looking at the SF ₆ recovery efficiency of the SF ₆ recovery apparatus manufactured according to an embodiment of the present invention. FIG. 6 is a graph illustrating concentrations of SF ₆ contained in an exhaust gas and a recovered gas in an SF ₆ recovery apparatus according to an embodiment of the present invention, wherein the injected gas is 90: The ratio of 10 is a mixed gas of N ₂ : SF ₆ , which is an experimental result conducted at a temperature of 100 ° C. As shown in Figure 6, it can be seen that the concentration of SF ₆ occupies 90% or more in the gas recovered by the SF ₆ recovery apparatus according to an embodiment of the present invention exhibits a high recovery rate.

1 is a perspective view of the SF ₆ membrane module according to an embodiment of the present invention.

2 is a cross-sectional view of the SF ₆ membrane module according to an embodiment of the present invention.

3 is a block diagram of a SF ₆ recovery apparatus according to an embodiment of the present invention.

4 is a flow chart for explaining the operation of the SF ₆ recovery apparatus according to an embodiment of the present invention.

4 is a graph showing the adsorption performance of SF ₆ , O ₂ , N ₂ , CO ₂ according to pressure under an isothermal temperature of 303K.

5 is a graph showing the concentration of SF ₆ contained in the gas (exhaust gas) and recovered gas (recovered gas) in the SF ₆ recovery apparatus according to an embodiment of the present invention.

Description of the main parts of the drawing

110 gas separation membrane 111 gas separation tube

112: gas discharge hole 113: fixing strip

120 chamber 121 gas inlet

122: first outlet 123: second outlet

124: Separator

301: mixed gas supply tank 302: mixed gas stabilization tank

303: constant temperature holding device 304: SF ₆ membrane module

305: SF ₆ recovery tank 306: other gas recovery tank

307: concentration measuring device

Claims (15)

chamber; And It is provided in the chamber and comprises a gas separation membrane composed of a plurality of gas separation tube, A plurality of gas discharge holes are provided on the surface of the gas separation tube, wherein the diameter of the gas discharge holes is smaller than the molecular diameter of SF ₆ SF ₆ membrane module. The SF ₆ membrane module of claim 1, wherein the gas separation membrane and the inner wall of the chamber are spaced apart from each other by a predetermined distance. The SF ₆ membrane module of claim 1, further comprising a fixing band configured to surround and fix the gas separation membrane at both ends of the gas separation membrane. According to claim 1, wherein one end of the chamber is provided with a gas inlet through which the mixed gas containing SF ₆ is introduced, the other end of the chamber is provided with a first outlet for discharging SF ₆ , the mixing of one side of the chamber SF ₆ membrane module, characterized in that provided with a second outlet for discharging the gas except SF ₆ in the gas. The method of claim 1, wherein the gas separation membrane module tubes are SF _6, characterized in that consisting of SF ₆ adsorption degree of the falling material in the mixed gas containing SF ₆ The SF ₆ separator module according to claim 1, wherein the plurality of gas separation tubes are in close contact with each other to form an aggregate. The method of claim 1, wherein the gas discharging hole is SF is larger than the molecular diameter of the gas other than the SF ₆ in a mixed gas comprising SF _{6 6} separation membrane module. The method of claim 1, wherein the gas separation tube is polysulfone, carbon, polyimide, polycarbonate, polyester, polyestercarbonate, polyestersulfone SF ₆ membrane module, characterized in that made of any one, polyamide (polyamide), polyphenylene (polyphenylene). The SF ₆ membrane module of claim 2, further comprising separator plates on both ends of the chamber, wherein the space between the gas separation membrane and the inner wall of the chamber is separated from the outside by the separator. A mixed gas supply tank for storing a mixed gas including SF ₆ ; A mixed gas stabilization tank receiving a mixed gas from the mixed gas supply tank and maintaining a constant SF ₆ concentration in the mixed gas; An SF ₆ separator module for separating the mixed gas supplied from the mixed gas stabilization tank into SF ₆ and other gases; And SF ₆ recovery device, characterized by that along with providing a mounting space of the SF ₆ separation membrane module comprising a constant-temperature maintaining device which serves to maintain a constant temperature in said SF ₆ separation membrane module. 11. The method of claim 10, SF ₆ and collecting apparatus according to claim 1, further comprising the SF ₆ gas collecting tank and the other tank for storing the recovered SF ₆ SF _6, and other gas separation membrane modules separated by each. 12. The method of claim 11, SF ₆ and collecting apparatus according to claim 1, further comprising a concentration measurement device for measuring the SF ₆ SF ₆ concentration in the recovery tank. The SF ₆ recovery apparatus according to claim 10, further comprising a temperature controller for controlling the temperature of the mixed gas stabilization tank on one side of the mixed gas stabilization tank. The SF ₆ recovery apparatus according to claim 10, further comprising an impurity removal filter for filtering impurities contained in the mixed gas at an inlet end of the mixed gas stabilization tank. 11. The method of claim 10, wherein the separation membrane module SF ₆ SF ₆ and collecting apparatus of claim 1, characterized in that SF ₆ separation membrane module.

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