JP6516335B2 - Target gas treatment system - Google Patents

Description

  The present invention relates to a target gas treatment system for treating an exhaust gas containing spent target gas and air obtained from an apparatus in which the target gas is used.

  A nanoimprint semiconductor manufacturing apparatus is used to manufacture a 3D memory. In this nanoimprint semiconductor manufacturing apparatus, in the nanoimprint step, manufacture is performed in a helium gas atmosphere which is an inert gas having a very small particle diameter in order to reduce the occurrence of defects in the semiconductor. In the nanoimprint process, placing the wafer in an appropriate helium gas atmosphere is the greatest know-how in improving the yield.

  On the other hand, the helium used is difficult to recycle because it can be recovered only when the air content is about 90%, and all of the helium is currently dissipated and used. Therefore, it is predicted that the amount of helium used for semiconductor production will be enormous if the production of a very small line width semiconductor using nanoimprint technology is put in orbit. Therefore, a technique for recovering and reusing helium as much as possible is desired.

  In addition, the circulation system of the helium relevant to this invention is disclosed by patent document 1 grade | etc., And it is shown by patent document 2-4 grade | etc., About refinement | purification of helium.

Patent No. 4145673 Patent No. 4893990 Patent No. 3645526 Patent No. 3686066

  Helium is threatened to deplete 20 years from now, and the price of helium has increased 4-5 times in the last 10 years, and the need for helium recovery is strongly pointed out, but such high Economically available helium recovery technologies do not yet exist from gases with proportions of contamination (contaminants: mainly air components).

The target gas processing system according to the present invention comprises a compressor for pumping an exhaust gas containing a target gas and air, and a membrane separation apparatus for separating a compressed gas from the compressor into a target gas enriched gas and a target gas low content gas. the target gas enriched gas from the membrane separation unit is cooled, possess a cryogenic unit for separating the target gas and air by the solidifying either air or target gas, the cryogenic apparatus A concentric or spiral flow passage that cools the target gas-enriched gas by flowing it from the outer circumferential side to the inner circumferential side sequentially from the outer circumferential side, and the outer circumferential side has a wider flow channel than the inner circumferential side. Do.

If the target gas from the membrane separation device is cooled and the air is separated in the cryocooler to separate air from the target gas whose solidification temperature is lower than that of air, the target gas is helium or neon Good.
  If the target gas enriched in gas from the membrane separation device is cooled and the target gas is separated from the air by solidifying the target gas in the cryogenic system, the target gas is xenon or argon It is good.

And a water lubricated compressor for pumping the exhaust gas containing the target gas and air, and a membrane separation device for separating the compressed gas from the water lubricated compressor into the target gas enrichment gas and the target gas low content gas. Good.

In addition , it is preferable that the target gas is preliminarily cooled by the heat exchanger, and the cryogenic air for separating the target gas and the air by solidifying the air or the target gas in the cooled target gas.

  According to the present invention, it becomes possible to recover helium gas containing a large amount of air components at a yield of 90% or more, achieving a significant reduction in production cost and achieving a reduction in production cost. It can contribute to the reduction of environmental load.

It is a block diagram which shows the whole structure of a helium gas circulation system. It is a figure which shows the structure of a pre-processing apparatus. It is a figure which shows the structure of the modification of a pre-processing apparatus. It is a figure which shows the structure of a water lubrication compressor. It is a figure which shows the structure of a membrane separation apparatus. It is a figure showing composition of a deep chiller. It is a figure which shows the structure of a cryogenic refinement | purification apparatus. It is a figure which shows the other structure of a cryogenic refinement | purification apparatus. It is a block diagram showing composition of a modification of helium gas circulation system It is a figure which shows the structure (closed state) of an electrically operated valve. It is a figure which shows the structure (open state) of an electrically operated valve.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The present invention is not limited to the embodiments described herein.

"overall structure"
FIG. 1 is a diagram showing an entire configuration of a helium circulation system. The semiconductor manufacturing apparatus 10 is for manufacturing a 3D memory, and includes a nanoimprint manufacturing apparatus. And the nanoimprint process by a nanoimprint manufacturing apparatus is implemented in the enclosed space (object space) where helium gas is supplied. In the region where helium gas is supplied, a helium gas atmosphere is provided, but the entire target space contains a large amount of air, and the exhaust gas discharged from this target space is typically helium gas. It will be about 10%, air about 90%.

  The exhaust gas flows into the pretreatment device 12 where it removes as much air from the exhaust gas as possible to obtain a helium enriched gas enriched to about 90% helium gas. Although the pretreatment device 12 will be described later, a membrane separation device, for example, a hollow fiber membrane separation device using a polyimide membrane is preferable. Moreover, a water lubricated compressor is suitable as a compressor for exhaust gas compression. In addition, as the compressor, an oil-free compressor is also suitable, and a compressor that uses ordinary oil can also be used. In this case, a device for removing oil from compressed gas is provided You should not spill it.

  The helium-enriched gas from the pretreatment unit 12 is supplied to the cryogenic unit 14. The chiller 14 cools the helium-enriched gas, solidifies the air, and purifies the helium gas. As a result, helium gas whose concentration is increased to about 90% is obtained, which is temporarily stored in the buffer tank 16 and then circulated to the semiconductor manufacturing apparatus 10. The semiconductor manufacturing apparatus 10 can also be supplied with helium gas from the helium cylinder 18 by the switching device.

"Preprocessor"
FIG. 2 is a view showing a configuration example of the pretreatment device 12 using the membrane separation device. The exhaust gas from the semiconductor manufacturing apparatus 10 is supplied to the buffer tank 114 by the pump 110 and temporarily stored there. The gas stored in the buffer tank 114 is compressed by the water lubrication compressor 116 and supplied to the subsequent stage. The water-lubricated compressor 116 can obtain a high pressure gas of about 0.9 MPa (gauge pressure, hereinafter the same).

  The compressed gas from the water lubricated compressor 116 is cooled by an aftercooler 118 which is a refrigeration type dehumidifier to remove water. The compressed gas from which water has been removed is temporarily stored in the buffer tank 120, and then heated or cooled to an appropriate temperature by the temperature controller 122 and supplied to the membrane separation device 124. This membrane separation device 124 utilizes, for example, a hollow fiber of polyimide, and separates helium and air by the difference in permeation rate to the membrane. That is, by supplying a mixed gas of helium and air to one side of the membrane under high pressure, helium having a high permeation rate of the membrane selectively passes through the membrane. As a result, a helium-enriched gas is obtained on the permeate side of the membrane separation device 124, and an air-enriched gas containing a large amount of air is obtained on the mixed gas supply chamber side. The permeation rate of helium gas in the membrane separator 124 is relatively low, thus requiring membrane separation at high pressure. Although it is difficult to sufficiently increase the concentration of helium only by using the water-lubricated compressor 116 and the membrane separation device 124, there are also applications where the helium-enriched gas obtained by the membrane separation device 124 can be used as it is.

  In order to increase the helium concentration, the helium-enriched gas obtained by the membrane separation unit 124 is compressed again by the water lubricated compressor 128 via the buffer tank 126. The compressed gas is dehumidified by the cooling dehumidifier 130 and stored in the buffer tank 132, and then supplied to the membrane separation device 138 via the temperature controller 134 and the pressure reducer 136. Here, in the second stage membrane separation apparatus 138, the supply pressure is set to about 0.6 MPa, which is lower than that of the first stage membrane separation apparatus 124. As a result, the amount of membrane permeation of air can be reduced to effectively obtain a permeate gas having a large ratio of helium gas.

  The helium-enriched gas obtained by the second stage membrane separation apparatus 138 is decompressed to about 0 MPa (atmospheric pressure) by the decompressor 142 and is delivered to the cryogenic apparatus 14.

  Further, the air-enriched gas in which the helium gas on the supply side of the first stage membrane separation device 124 decreases and the proportion of air increases is supplied to another membrane separation device 146 via the temperature controller 144. By permeating at the gas temperature and pressure such that substantially only air can be obtained on the permeation side, the substantially air-only gas is released. On the other hand, on the supply side, the air is removed and a gas enriched with helium gas is obtained (for example, containing about 50% of helium gas), which is brought to almost atmospheric pressure by the pressure reducing valve 148 and the buffer tank 114 It is circulated to

  The exhaust gas (for example, containing about 85% of helium gas) from the supply side of the second stage membrane separation apparatus 138 is circulated to the buffer tank 114 with the atmospheric pressure (0 MPa) almost via the pressure reducing valve 150. Note that part of the exhaust gas from the aftercooler 118 may be circulated to the buffer tank 114 to adjust the gas supply amount to the rear stage.

  A helium enrichment gas containing about 95% of helium gas can be obtained by the pretreatment device 12 including three membrane separation devices and two water lubricated compressors. Moreover, since dehumidification is also performed, the dew point can be made less than -15 ° C. Also, the yield of helium can be as high as 98%.

"Modification of pre-processing device"
The above example includes three membrane separators and two water lubricated compressors. Thus, the system is relatively large. If the helium gas concentration is allowed to be low, a more compact system can be made.

  FIG. 3 shows a system with two membrane separators and one water lubricated compressor. An exhaust gas with atmospheric pressure of 90% air and 10% helium gas is supplied to a buffer tank 212 by a pump 210. After the gas in the buffer tank 212 is pressurized by the water lubrication compressor 214, the gas is dried by the after cooler 216 and introduced into the buffer tank 218. A part of the buffer tank 218 is circulated to the buffer tank 212 via the pressure reducing valve 244, and the gas flow rate to the subsequent stage is adjusted.

  The gas from the buffer tank 218 is supplied to the dryer 220 where it is further dried. The dryer 220 is, for example, an adsorption type dehumidifier, and a pressure swing adsorption (PSA) type dryer is employed. In this PSA, a plurality of towers packed with a hygroscopic agent (adsorbent) such as zeolite are prepared, and when moisture is absorbed under high pressure in one tower, regeneration under low pressure is performed in the other tower. The regeneration gas is returned to the buffer tank 212 via the pressure reducing valve 222. It is possible to make dew point -70 degrees C or less by this dryer 220.

  The gas dried by the dryer 220 is supplied to the membrane separation device 224 while maintaining a high pressure (for example, 0.9 MPa). It is preferable that this membrane separation device 224 also utilizes a hollow fiber membrane of polyimide. As helium selectively permeates through the membrane, a helium-enriched gas is obtained on the permeate side, which is stored in the buffer tank 228 via the control valve 226. The helium-enriched gas in the buffer tank 228 is supplied to the chiller 14 through the pressure reducing valve 230.

  Note that part of the helium-enriched gas is returned to the buffer tank 212 via the control valve 232 and the pressure reducing valve 234. Therefore, by controlling the control valves 226 and 232, the circulation amount can be controlled, and the helium content rate in the buffer tank 212 can be set to an appropriate value.

  The gas on the supply side of the membrane separation device 224 is supplied to the membrane separation device 238 via the control valve 236. A gas that is rich in helium gas through the membrane is circulated to the buffer tank 212 via the control valve 240 and the pressure reducing valve 242. On the other hand, air containing almost no helium is obtained on the non-permeation side of the membrane separation device 238 and is exhausted to the outside.

  In this example, two membrane separation devices and one water lubricated compressor are provided, and the system configuration is simplified as compared with the above-described example. And since it was set as the structure which can be recirculated to a front | former stage at each step, the enrichment rate of helium can be raised and desired helium enrichment gas can be obtained by setting of the suitable amount of circulation.

"Water lubricated compressor"
FIG. 4 shows a schematic configuration of a water lubricated compressor. The compressor body 310 rotates the blades by a motor to compress and discharge the fluid on the suction side. Here, water and gas to be compressed are supplied to the compressor body 310, and the compressed gas mixed with water is discharged. The water-containing compressed gas is supplied to the reservoir tank 312 where it is separated into gas and liquid. Then, the gas in the reservoir tank 312 is discharged to the next stage (membrane separation device) as compressed gas through the control valve 320.

  Further, a drain pipe having a valve 322 is connected to the bottom of the reservoir tank 312, and the drain pipe is appropriately drained. In addition, new water is supplied so that the water level of the reservoir tank 312 is maintained constant.

  Water in the reservoir tank 312 is circulated to the compressor body 310 via the cooler 314, the filter 316 and the valve 318.

  As described above, by circulating and supplying water to the compressor main body 310, the oil can be eliminated and the gas can be compressed.

"Membrane separation device"
FIG. 5 shows the configuration of the membrane separation apparatus. An inlet 612 is provided at one end of the cylindrical holder 610, and an outlet 614 is provided at the other end, and a plurality of axially extending hollow fibers 616 are disposed therein.

  The inlet side sealing body 618 is provided on the inlet side of the hollow fiber 616, and the outlet side sealing body 620 is provided on the outlet side. The inlet side sealing body 618 and the outlet side sealing body 620 seal the outer space of the hollow fiber 616 in the holder 610, and the space on the inlet side 612 of the inlet side sealing body 618, and the outlet side. The space on the outlet 614 side of the sealing body 620 is in communication with the inside of each hollow fiber 616. Further, the middle portion of the holder 610 is provided with a discharge port 622 communicating with the inside, and the outer space between the inlet-side sealing body 618 in the holder 610 and the outlet-side sealing body 620 is the discharge port 622 It communicates.

  Therefore, the helium gas in the gas to be treated (compressed gas) introduced from the inlet 612 selectively moves from the inside to the outside of the hollow fiber 616 and permeates the hollow fiber to reach the outside space. A helium-enriched gas is obtained at outlet 622, including. In addition, the outlet 614 provides an air-enriched gas in which helium gas is reduced and air is abundant.

"The deep chiller"
The structure of the cryogenic device 14 is shown by FIG. In this example, the helium-enriched gas (approximately 90% helium gas) from the pretreatment device 12 flows into a spiral heat exchanger (SHE) 410. In the spiral heat exchanger 410, two spiral channels are adjacent to each other, and one channel is made to flow hot gas, and the other channel is made to flow cold gas. It is a countercurrent heat exchanger in which the outlets are adjacent. The first stage helium-rich gas flows into the spiral heat exchanger 410 as a high temperature gas, is cooled by heat exchange with the low temperature gas, and flows out. For example, it is cooled to 290K to 150K.

  The helium enriched gas from the spiral heat exchanger (SHE) 410 flows into the second stage spiral heat exchanger (SHE) 412 where it is further cooled. For example, it is cooled to 150K to 90K. By using an appropriate spiral heat exchanger 410, the cooling capacity required in the next stage cryogenic refiner 414 can be significantly reduced.

  Then, the obtained cooled helium-enriched gas flows into the cryogenic refiner 414 through the valve 422. The cryogenic purifier 414 is a refrigerator having a long flow path (helical flow path) made of a material having good heat conductivity. For example, the incoming gas is cooled to 35 K at 90 K. Here, the helium-enriched gas contains about 10% of air, and the air freezes and solidifies in the cryogenic refiner 414.

  The air in the helium-enriched gas flowing in from the outer inlet solidifies, and the non-solidified helium gas flows out from the central outlet. And, at this outlet, a capturing body 432 is disposed, which further freezes and solidifies and removes impurities (air) in the gas. For the capturing body 432, for example, a foam metal capturing body described in Patent Document 2 can be used. The capturing body 432 is also cooled by the refrigerator in the same manner as the deep-refining purifier 414.

  The capturing body 432 is in an annular shape, and provided in multiple stages with respect to the flow direction of the helium gas. The metal foam material has a three-dimensional network structure as found in a sponge, and the holes in the mesh are continuous. Thus, fluid can pass through this portion of the hole. In addition, the pore diameter of the foam metal material constituting the capturing body 432 may be arranged to be smaller and finer as it goes downstream. For example, Celmet (trade name) manufactured by Sumitomo Electric Co., Ltd. can be used as the foam metal material. Moreover, nickel or its alloy, copper, etc. are employable as a metal which comprises foam metal material. The concentration of the 35 K regenerated helium gas thus obtained is 99.9% or more.

  Then, the 35 K regenerated helium gas is supplied to the second stage spiral heat exchanger 412 as a low temperature side gas. It flows in at around 35 K, rises in temperature to around 140 K and flows out. The 140 K regenerated helium gas flows into the first-stage spiral heat exchanger 410 as a low temperature side gas. Then, it is heated to about 280 K and flows out, and is stored in the buffer tank 416 via the valve 424. Then, the regenerated helium gas from the buffer tank 416 is circulated to the semiconductor manufacturing apparatus 10 through the valve 418. The helium gas cylinder 420 is connected to the supply path of the helium gas to the semiconductor manufacturing apparatus 10 through the valve 428, and the helium gas from the helium gas cylinder 420 is the semiconductor manufacturing apparatus by switching the valves 418 and 428. Supplied to 10

  Here, the cryogenic refiner 414 solidifies the air and takes out helium gas. Therefore, the cryogenic refiner 414 is regenerated when a predetermined period of time has come. That is, when the regeneration time is reached, the valves 422 and 424 are closed, the valve 426 is opened, and the cryogenic refining device 414 is heated to gasify and discharge the water having low moisture and solidification temperature first. Next, the valve 422 is opened, the refrigerator for cooling the deep-refining purifier 414 is stopped, and the deep-refining purifier 414 is heated by a heater or the like to remove solidified air. Since the pump 430 is connected to the valve 426, the valve 424 is closed, the valve 426 is opened, and by driving the pump 430, the air evaporated in the cryogenic refiner 414 is exhausted through the valve 426. During this regeneration process, the helium gas stored in the buffer tank 416 is used. The valve 422 operating at a low temperature is important to prevent water and miscellaneous gas trapped in the spiral heat exchanger 412 from flowing into the cryogenic refiner 414, but when such contamination (impurity gas) is small May be omitted.

<Cryogenic refiner>
Here, a configuration example (schematic diagram) of the cryogenic refining device 414 is shown in FIG. In this example, the cryogenic refiner 414 is comprised of a vessel including concentrically arranged metal cylinders 440. Concentric flow paths are formed by a plurality of cylinders 440, and each cylinder 440 is provided with an opening at a position different by 180 ° from the adjacent one. Accordingly, the gas flowing into one end of the annular flow path moves 180 ° and flows into the adjacent flow path from the opposite side. The container is made of a heat conductive metal such as oxygen free copper or aluminum.

  In this example, the inflow port 442 is provided in the outermost flow path, and the outflow port 444 is provided in the center, and the width is wider as the outer path. The air in the gas flowing into the cryogenic refiner 414 is frozen and becomes solid and adheres to the wall of the flow path, but if the gas is sufficiently cooled by SHE and it is just before the liquefaction temperature of the contamination, it solidifies The amount is larger on the inflow side. By making the outer passage wider and making the flow passage smaller, it is possible to make the time until the flow passage is blocked due to the adherence of air relatively uniform as the whole flow passage, and therefore the same volume of cryogenic purifier 414 The period of continuous use can be extended.

  Another example of the cryogenic refiner 414 is schematically shown in FIG. As described above, even when the passage is formed into a spiral and flows from the outside and is discharged from the center, the use period can be extended similarly to the above-mentioned case by increasing the width of the passage toward the inflow side.

  In order to solidify the contamination gas efficiently in the cryogenic refiner, a baffle plate or the like may be appropriately installed in the flow path. In this case, since more contamination is solidified in the baffle portion, it is highly likely that clogging of the purifier will occur early, and therefore, it is necessary to set the solidification to occur as evenly as possible.

  In addition, it is preferable that the deep chiller 14 be disposed in a vacuum vessel so as not to receive heat in the deep chiller and prevent dew condensation in the low temperature section.

"Other configuration"
<2 series deep chillers>
FIG. 9 shows an example of the configuration of a cryogenic system. In this example, two cryogenic apparatuses 14-1 and 14-2 are provided as the cryogenic apparatuses. Therefore, while processing is being performed on one side, reproduction on the other side is possible. Preferably, such switching is performed automatically by the controller. In addition, when making the freezing apparatus 14 into 1 series, it is good to enlarge the buffer tank of the front | former stage, and to store the helium enrichment gas in process of regeneration of the freezing apparatus 14. As shown in FIG.

  The device that applies the recovery and circulation of helium gas may not be a semiconductor manufacturing device as long as it is a device that uses a large amount of helium gas. For example, it can be used for an optical fiber manufacturing apparatus, an LCD (liquid crystal display) manufacturing apparatus, and the like. Also, depending on the application where the helium concentration does not have to be high, the purification in the deep-cooling device 14 may be omitted, and the helium-enriched gas from the pretreatment device 12 may be supplied directly to a helium gas using device such as a semiconductor manufacturing device. May be

<Low temperature operation valve>
During regeneration of the cryogenic refiner 414 as described above, the valve 422 often has to be closed in advance. In this case, it is necessary to operate the valve at a relatively low temperature.

  Although it is desirable to use a motorized valve that can be automatically controlled for such a valve, there is no one that can guarantee the operation even if the drive unit becomes extremely low temperature, and the motored valve is further It is necessary to flow, and the amount of heat generated is a problem. Therefore, a manual valve is usually employed.

  Here, according to the motor-operated valve shown in FIGS. 10 and 11, it is not necessary to flow a current to maintain the open state and the closed state, and it is sufficient to flow the current only when the state is changed. Therefore, it is preferable to use this motorized valve as the valve 422.

  The motor-operated valve 500 has a generally cylindrical valve body 510. Inside the valve body 510, a first flow passage 512 and a second flow passage 514 are formed. The first flow passage 512 has an opening 512a on the outer peripheral surface in the radial direction of the valve body 510, and turns from there to a central direction and then axially bent to have a V-shaped flow having an opening 512b on the surface on one end side. It is a road. On the other hand, the second flow passage 514 is a flow passage extending in the axial direction, and is a linear flow passage having an opening 514a on one end side and an opening 514b on the other end side.

  The open side of the cylindrical container-like housing 520 is attached to cover one end side of the valve body 510. That is, one end of the valve body 510 is substantially flat, and the end of the housing 520 is attached to the periphery thereof. The valve body 510 is formed of, for example, stainless steel (SUS316L, SUS304, etc.).

  An annular cylinder 522 is installed on the inner circumferential side of the housing 520 on the valve body 510 side. One end side of the cylinder 522 is in contact with the one end side surface of the valve body 510, and by sealing this, a sealed space is formed inside. The openings 512b and 514a of the first and second flow channels 512 and 514 open into the sealed space. The housing 520 and the cylinder 522 are also made of stainless steel similar to the valve body 510.

  A cylindrical plunger 524 is disposed on the inner peripheral side of the cylinder 522 so that the outer peripheral surface thereof is in contact with the inner peripheral surface of the cylinder 522. The plunger 524 is axially movable. A seat 526 is attached to the end face of the plunger 524 on the valve body 510 side. Therefore, the sheet 526 is located on the plunger 524 side of the sealed space. The central portion of the sheet 526 is convex in a chevron shape, while the opening 514a of the second flow passage 514 of the valve body 510 is tapered in the periphery and has a shape in which the both coincide with each other. . Therefore, when the plunger 524 is pressed against the valve body 510, the second flow passage 514 is closed, and the electric valve 500 is closed. The plunger 524 is preferably made of magnetic material such as permalloy B or Invar. These materials are ferromagnetic materials and are small in conversion of characteristics as a magnetic material even at low temperatures, and thus are suitable for an apparatus used at low temperatures as in this embodiment. In addition, steel materials such as SUS430 and SUM23 can also be used. The sheet 526 is made of, for example, PTFE (polytetrafluoroethylene), polyimide or the like. Polyimide is less likely to change its characteristics even at low temperatures, can maintain its deformation characteristics, and is particularly suitable as a sheet 526 as a sealing material.

  A cylindrical solenoid coil 528 is disposed rearward of the cylinder 522 (opposite to the valve body 510). The rear side of the plunger 524 extends rearward from the rear end of the cylinder 522, and is positioned inside the solenoid coil 528 at a predetermined interval.

  Behind the plunger 524, a cylindrical base core 530 of a magnetic body is disposed. Base core 530 can be constructed of the same material as plunger 524. A disc or annular magnet (permanent magnet) 532 is disposed behind the base core 530 and the solenoid coil 528. Base core 530 and magnet 532 are fixed to housing 520. The magnet 532 is formed of, for example, neodymium. A cylindrical recess is formed on the rear side of the plunger 524, and a spring 534 is disposed between the front end of the recess and the front end of the base core 530. The spring 534 is a compression spring and biases the plunger 524 forward. The spring 534 is formed of, for example, Inconel (Inconel 750 or the like). Inconel has a sufficient elasticity as a spring material and has a small change in elastic coefficient even at low temperatures, so it is particularly suitable as a spring 534 as a biasing member of the plunger 524 in this embodiment.

"Action"
First, in the state shown in FIG. 10, that is, in the closed state of the motor-operated valve 500, the plunger 524 and the seat 526 are pressed against the valve body 510 by the biasing force of the spring 534. Accordingly, the flow of fluid between the first flow passage 512 and the second flow passage 514 is stopped. Although the plunger 524 is drawn toward the magnet 532 by the magnetic force of the magnet 532, the biasing force of the spring 534 is set larger, so the plunger 524 is stable in a state of being pressed against the valve body 510. .

  Here, a current in one direction is supplied to the solenoid coil 528 (one-way current flow direction), and the solenoid coil 528 generates a suction force in the same direction as the magnet 532 on the plunger 524. As a result, magnetic lines of force pass through the plunger 524 and the base core 530, and the plunger 524 receives a rearward force in combination with the magnetic force of the magnet 532. This force is greater than the biasing force of the spring 534, so the plunger 524 moves rearward and catches on the base core 530. That is, the front end surface of the base core 530 and the rear end surface of the plunger 524 are flat in the direction perpendicular to the axis, and both contact as a whole. And, since the attraction force by the magnetic force is in inverse proportion to the square of the distance, the attraction force when the distance to the base core 530 becomes zero is large, and even after the current to the solenoid coil 528 is cut off, The force is greater than the biasing force of the spring 534. Therefore, as shown in FIG. 11, the attraction force of the magnet 532 stably holds the plunger 524 in the state of being positioned on the rear side. That is, in a state in which no current flows to the solenoid coil 528, the motor-operated valve 500 is maintained in the open state.

  Next, current is applied to the solenoid coil 528 in the direction opposite to the above one direction (the current supply direction is reversed). As a result, magnetic lines of force pass through the base core 530 and the plunger 524 to generate a magnetic field in the direction to cancel the magnetic force from the magnet 532 with respect to the plunger 524. As a result, the biasing force of the spring 534 is larger than the magnetic force from the magnet 532, thereby returning to the state of FIG. 10.

  As described above, according to the present embodiment, when the electric valve 500 is switched between the closed state and the open state, the electric valve 500 can be switched between open and closed by supplying a current in a predetermined direction to the solenoid coil 528. Therefore, the energization time is short, and the influence of heat generation by energization of the solenoid coil 528 to the motor-operated valve 500 can be suppressed.

"Effect of the embodiment"
According to this embodiment, a large amount of contamination (air) is dropped to 10% or less in the pretreatment device 12 including the membrane separation device (polyimide hollow fiber membrane). Then, the contamination left by the pretreatment device 12 is cooled to about 35 K in the cryogenic refiner 414 of the cryogenic device 14 with high thermal efficiency using a spiral heat exchanger (SHE) to solidify and remove the contamination. , Helium gas with a concentration of 99.9% or more is recovered at a recovery rate of 90% or more.

  In this way, helium can be recovered and circulated in high yield. Therefore, in the field where helium gas is used as a production auxiliary gas, it is possible to reduce the production cost, and it is possible to achieve effective use of the helium resource which may be depleted.

"Appendix"
The specification and drawings also describe inventions not described in the claims. Therefore, this will be described below.

<Pre-processing>
[Configuration 1]
The pretreatment device has a plurality of stages of membrane separation apparatus, and supplies the air-enriched gas obtained by the membrane separation apparatus of the former stage to the membrane separation apparatus of the latter stage to obtain a helium-enriched gas, which is subjected to the membrane separation of the former stage It may be returned upstream of the device. The helium concentration can be increased by providing a two-stage membrane separation apparatus. In addition, the helium concentration can be set to a desired one by adjusting the circulation amount.
[Configuration 2]
It is good to include a freezing dehumidifier which removes moisture by freezing. By freezing the compressed gas, water can be effectively removed.
[Configuration 3]
It is good to include a hygroscopic device using a moisture adsorbent. Water can be removed by using a known hygroscopic agent (water adsorbent) such as zeolite. It is also preferred to use both a freezing and dehumidifying device. By using a moisture adsorbent as PSA, continuous operation becomes easy.
[Configuration 4]
If the number of membrane separators, the number of compressors is one, two or more, and the amount of feedback gas from each membrane separator to the previous stage is adjusted to set the yield and the helium gas concentration to desired values Good. The pretreatment device can be considered in various variations. It is preferable to adjust the number of membrane separation devices and compressors according to the requirements for the devices. In addition, by adjusting the circulation amount, it is possible to adjust the helium concentration, the yield and the like of the obtained gas.

<Deep Refrigeration Purification Equipment>
[Configuration 1]
A cryogenic refining apparatus having a unidirectional flow path from an inlet to an outlet, cooled by a refrigerator, solidifying and removing impurities, the flow path having a small cross-sectional area from the inlet side to the outlet It is good to become. By setting the cross-sectional area of the flow path, air solids can be deposited throughout the apparatus, enabling long-term use. If the heat exchanger in the previous stage does not cool the gas temperature to just before the liquefaction temperature, the flow path in the vicinity of the inlet of the cryogenic refining device is narrowed, broadened near the beginning of liquefaction, and then gradually narrowed. Is also suitable.
[Configuration 2]: Cryogenic purification apparatus using cylindrical row purifier A concentric flow path is formed in the vessel, an inlet is formed in the outermost flow path, an outlet is formed in the center, and an adjacent inner side is formed. The communication opening with the flow passage may be formed on the opposite side of the circle sequentially. A relatively long flow path can be obtained by forming a plurality of cylindrical (donut) flow paths. In addition, by making the inlet and the outlet of the cylindrical flow channel on the opposite side, the gas from the inlet is split into two semicircular flow channels, and they merge at the outlet, effectively using the entire flow channel it can.
[Configuration 3]: Cryogenic Purification Device Using a Spiral Purifier A spiral channel may be formed in the container, an inlet may be formed in the outermost channel, and an outlet may be formed in the center. By means of the spiral flow path, a long flow path can be easily obtained and sufficient cooling can be performed.
[Configuration 4]
A baffle may be disposed in the flow passage in the container. By providing the baffle plate, the gas flow is spread throughout the flow path, and effective solidification of air can be performed using the entire flow path.

<Heat exchanger>
The heat exchanger may be countercurrent, flowing two gases in opposite directions in adjacent passages. By making it countercurrent, efficient heat exchange can be performed.

<Circulation system>
[Configuration 1]
The circulation system may have two or more cryogenic units, and while one is regenerated, another cryogenic unit may be used to purify the purified helium gas. Such helium gas circulation system is suitable for mass gas processing.
[Configuration 2]
It is good to use purified helium gas which is previously purified and stored in a buffer tank while regenerating or purifying purified helium gas at an unnecessary time by using a single refrigerator. Suitable for relatively small amounts of gas treatment.

<Other features>
[Configuration 1]
In order to remove the water content of the gas to be treated, it is preferable to use the above-described cryogenic refining device. It is possible to achieve ultra low dew point, dew point -100 ° C or less.
[Configuration 2]
It is good to use an absorption tower (PSA) which absorbs contamination (air) instead of the membrane separation device (pre-treatment device). For example, the gas compressed in a water-lubricated compressor is dehumidified by a hygroscopic device (dryer such as a refrigeration type), dehumidified by a PSA type dehumidifier, concentrated by a PSA type air removal device, and concentrated by helium The gas may be processed in a cryogenic system. It can be a simple system, and depending on the application, such a system may be suitable.

DESCRIPTION OF SYMBOLS 10 Semiconductor manufacturing apparatus, 12 pretreatment apparatus, 14 deep cooling apparatus, 16 buffer tank, 18 helium cylinder, 110 pump, 114, 120, 126, 132 buffer tank, 116, 128 water lubrication compressor, 118 aftercooler, 122, 134 , 144 Temperature Controller, 124, 138, 146 Membrane Separator, 130, 140 Cooling Dehumidifier, 136, 142 Pressure Reducer, 148, 150 Pressure Reducing Valve.

Claims (14)

A compressor for pumping the exhaust gas containing the target gas and air;
A membrane separation apparatus for separating compressed gas from a compressor into target gas-enriched gas and target gas low-containing gas;
A cryogenic apparatus the target gas-enriched gas from the membrane separation unit is cooled, it separates the Target gas and air by the solidifying either air or target gas,
I have a,
The cryocooler is a flow passage for cooling by flowing the target gas enriched gas from the outer peripheral side to the inner peripheral side sequentially from the outer peripheral side in a concentric or spiral shape, and the channel width on the outer peripheral side is wider than that on the inner peripheral side to have a flow path,
Target gas treatment system. The target gas treatment system according to claim 1, wherein
The chiller is
A heat exchanger for preliminary cooling of the target gas enriched gas from the membrane separation device;
A cryogenic refiner for separating air from the target gas by solidifying air or target gas in the pre- cooled target gas- enriched gas from the heat exchanger ;
Have
Target gas treatment system. The target gas treatment system according to claim 2, wherein
The heat exchanger performs heat exchange between the target gas or air separated by the cryogenic purifier and the target gas enriched gas from the membrane separation device.
Target gas treatment system. The target gas treatment system according to claim 2 or 3, wherein
Heat exchanger, Ru Der spiral heat exchanger having a spiral flow path,
Target gas treatment system. The target gas treatment system according to any one of claims 2 to 4, wherein
Having a cryogenic motorized valve in the flow path from the heat exchanger to the cryogenic refiner,
Target gas treatment system. The target gas treatment system according to any one of claims 2 to 5, wherein
A target gas processing system, comprising a capturing body for freezing and capturing a solidifying gas from an output gas in a cryogenic refiner. The target gas treatment system according to any one of claims 2 to 6, wherein
A target gas processing system having a regenerating function, which enables separation of a target gas again in the cryogenic refiner by heating and gasifying the target gas or air solidified in the cryogenic refiner and recovering or discarding it. The target gas treatment system according to any one of claims 1 to 7, wherein
The membrane separation apparatus circulates part of the target gas enriched gas obtained on the permeate side of the membrane separation apparatus upstream of the compressor.
Target gas treatment system. The target gas treatment system according to any one of claims 1 to 8, wherein
The membrane separation device is a hollow fiber membrane separation device using a hollow fiber membrane,
Target gas treatment system. The target gas treatment system according to any one of claims 1 to 9 , wherein
The membrane separator is a membrane separator using a polyimide membrane,
Target gas treatment system. The target gas treatment system according to any one of claims 1 to 10, wherein
The compressor is a water lubricated compressor,
Target gas treatment system. The target gas treatment system according to any one of claims 1 to 11, wherein
Target gas is Ri helium or neon der,
Solidify the air in the cryocooler ,
Target gas treatment system. The target gas treatment system according to any one of claims 1 to 11, wherein
Target gas is Ri xenon or argon der,
Solidifying the target gas in the cryogenic system ,
Target gas treatment system. The target gas treatment system according to any one of claims 1 to 13, wherein
Supply the obtained target gas to the target space
Target gas treatment system.