Online analysis system for efficiently treating fluorine-containing gas

Abstract

The utility model discloses an on-line analysis system for efficiently treating fluorine-containing gas, which is characterized by comprising an alkali washing tank (1), a water washing tank (5), a vacuum pump (7), a cyclone separator (8), a condenser (11), a dryer (16), a gas chromatograph (21) and a water collecting tank (25) which are sequentially connected through pipelines, an outlet pipeline of the cyclone separator (8) passes through a cyclone separator outlet three-way ball valve (10), and an outlet pipeline of the gas chromatograph (21) is connected with the water collecting tank (25). One path is connected with a condenser (11), and the other path is connected with a condenser outlet three-way ball valve (13) and a second needle valve (15) and then goes to a waste gas treatment system; and the water collecting tank (25) is connected with a fluorine-containing gas return system to form a loop. The system can realize rapid gas replacement and complete drying, is easy to maintain, can effectively improve the accuracy of analysis results, and reduces the labor cost.

Description

Technical Field

[0001] The utility model relates to a processing system capable of online high-efficiency and continuous analysis in the production process of fluorine-containing gases such as NF3, CF4, SF6, etc. Background Art

[0002] During the online analysis of fluorine-containing gas production processes such as NF3, CF4, and SF6, untreated fluorine-containing gases (such as HF, F2, etc.) will cause irreversible damage to the gas chromatograph. Therefore, the fluorine-containing gas should be pretreated before gas component analysis. At present, the pretreatment process is mostly adopted: the fluorine-containing gas enters the gas chromatograph for analysis after multi-stage alkaline washing, silica gel column adsorption and drying. There are some problems with this process, such as a lot of water mixed in the outdoor pipeline before entering the chromatographic analysis room (especially in summer), which can easily affect the use effect and analysis accuracy of the Nafion tube dryer; the alkaline washing process is not completely washed, and the alkaline solution enters the subsequent pipeline and causes blockage; the silica gel column requires frequent manual replacement of silica gel, etc. Summary of the invention

[0003] In view of the problems existing in the prior art, the purpose of the utility model is to provide an online analysis system for efficiently processing fluorine-containing gases, which can achieve rapid gas replacement, complete drying, and easy maintenance, and can effectively improve the accuracy of analysis results and reduce labor costs.

[0004] In order to meet the above requirements, the technical solution adopted by the utility model is: an efficient online analysis system for processing fluorine-containing gases, characterized in that it includes an alkali washing tank 1, a water washing tank 5, a vacuum pump 7, a cyclone separator 8, a condenser 11, a dryer 16, a gas chromatograph 21 and a water collecting tank 25. The above-mentioned equipment is connected in sequence through pipelines. The outlet pipeline of the cyclone separator 8 passes through the cyclone separator outlet three-way ball valve 10, one way is connected to the condenser 11, and the other way is connected to the condenser outlet three-way ball valve 13 and the second needle valve 15, and then goes to the exhaust gas treatment system; the water collecting tank 25 is connected to the fluorine-containing gas return system to form a loop.

[0005] Furthermore, a first flow meter 12 is installed on the outlet pipeline of the condenser 11 .

[0006] The dryer 16 is provided with a selective permeable membrane inside, which forms a sleeve structure with the outer wall. The inside of the membrane is a sample gas channel, and the outside of the membrane is a purge gas channel. The purge gas channel goes to the exhaust gas treatment system through the second flowmeter 18.

[0007] Furthermore, an automatic flow meter 19 and a filter 20 are installed on the pipeline connecting the dryer 16 and the gas chromatograph 21 .

[0008] Furthermore, a third flow meter 22 is installed at the outlet of the gas chromatograph 21 . The third flow meter 22 is connected to the fluorine-containing gas return system and is connected to the exhaust gas treatment system through a fourth needle valve 23 .

[0009] Furthermore, a first needle valve 9 is installed at the bottom of the cyclone separator 8, and then connected to the fluorine-containing gas return system.

[0010] Furthermore, a peristaltic pump 14 is installed at the bottom of the condenser 11 and then connected to a fluorine-containing gas return system.

[0011] Furthermore, a third needle valve 17 is installed at the bottom of the dryer 16, and then connected to the fluorine-containing gas return system.

[0012] Furthermore, an alkali washing vent valve 2 is installed on the alkali washing tank 1, and an alkali washing three-way ball valve 3 is installed at the bottom of the alkali washing tank 1, and then goes to the waste liquid tank; a water washing vent valve 4 is installed on the water washing tank 5, and a water washing three-way ball valve 6 is installed at the bottom of the water washing tank 5, and then goes to the waste liquid tank. The alkali washing vent valve and the water washing vent valve are used for pressure relief and liquid replenishment, and the alkali washing three-way ball valve and the water washing three-way ball valve are used for sampling analysis and liquid discharge. When the analysis result is lower than the process index, the liquid in the tank is replaced.

[0013] Furthermore, a fifth needle valve 24 is installed on the pipeline connecting the water collecting tank 25 and the fluorine-containing gas return system.

[0014] Furthermore, a drain ball valve 26 is installed at the bottom of the water collecting tank 25, and then the water goes to the waste liquid tank.

[0015] Furthermore, the cooling effect of the condenser should reach <5°C, preferably an electronic condenser; the condenser flow rate is preferably 0-10L / min; the peristaltic pump flow rate is preferably 5mL / min; the first flow meter range depends on the processing capacity of the selected condenser, preferably 100-300L / h; the second flow meter range is preferably 100-300L / h, and the third flow meter range is preferably 100-300mL / min. The above-mentioned flow meter is preferably a glass rotor flow meter, a metal rotor flow meter or a gas turbine flow meter.

[0016] The specifications and models of dryers and automatic flow meters can be selected according to specific needs.

[0017] Furthermore, the vacuum pump is preferably an acid- and alkali-resistant micro air pump, and the specific specifications and models are selected according to the dead volume size of the water alkali washing tank and its connecting pipeline.

[0018] Furthermore, the pore size of the filter is preferably ≤1 μm to prevent particulate matter from entering the gas chromatograph and subsequent pipelines, causing equipment damage or pipeline blockage.

[0019] Furthermore, the material of the pipeline through which the fluorine-containing gas flows is preferably polytetrafluoroethylene, and materials such as stainless steel, polytrifluoroethylene or tetrafluoroethylene-perfluoroalkoxy vinyl ether polymer may also be used.

[0020] Furthermore, the alkali washing tank and the water washing tank are preferably made of polytetrafluoroethylene, and may also be made of stainless steel or other materials. They are one-stage or multi-stage, and are equipped with acid- and alkali-resistant fillers.

[0021] Furthermore, the cyclone separator and the water collecting tank are preferably made of stainless steel, but carbon steel and other materials may also be used.

[0022] This pipe connection method can achieve rapid replacement of gas in the treatment system. It can enter the return gas system after analysis to save sample gas, and can also switch to the exhaust gas treatment system in time to reduce pollution when the analysis content is abnormal.

[0023] When treating fluorine-containing gas, the utility model adopts the process of alkali washing first and then water washing, which can effectively avoid the entrainment of alkali solution into the subsequent process; the condenser is used to replace the traditional silica gel column for water removal, which not only avoids the condensed water entering the dryer and causing its failure to affect the process, but also eliminates the workload caused by the silica gel column replacement operation; when the outdoor pipeline contains less water before entering the chromatographic analysis room (especially in winter), the valve can be switched to allow the gas to enter the dryer directly after coming out of the cyclone separator without passing through the condenser, thereby achieving energy saving and consumption reduction; adding a return air system and an exhaust gas treatment pipeline effectively avoids the loss and waste of sample gas and the pollution of the system by unqualified sample gas. The system can achieve efficient pretreatment of fluorine-containing gas, effectively reduce production costs, and is suitable for industrial production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to clearly illustrate the embodiments of the present utility model or the prior art solutions, the drawings required for use will be further described below. The drawings in the following description are only partial embodiments of the present utility model.

[0025] Figure 1 This is a schematic diagram of an embodiment provided by the utility model.

[0026] In the schematic diagram: 1. alkali washing tank, 2. alkali washing vent valve, 3. alkali washing three-way ball valve, 4. water washing vent valve, 5. water washing tank, 6. water washing three-way ball valve, 7. vacuum pump, 8. cyclone separator, 9. first needle valve, 10. cyclone separator outlet three-way ball valve, 11. condenser, 12. first flow meter, 13. condenser outlet three-way ball valve, 14. peristaltic pump, 15. second needle valve, 16. dryer, 17. third needle valve, 18. second flow meter, 19. automatic flow meter, 20. filter, 21. gas chromatograph, 22. third flow meter, 23. fourth needle valve, 24. fifth needle valve, 25. water collecting tank, 26. drain ball valve. DETAILED DESCRIPTION

[0027] In order to introduce the technical solution provided by the utility model in more detail, it is described in conjunction with the embodiments below. The following description of the embodiments of the utility model is for illustration only and does not limit the utility model and its application or use. Based on the embodiments mentioned in the utility model, other embodiments obtained by those skilled in the art without making any creative work belong to the protection scope of the utility model. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be regarded as part of the authorization specification.

[0028] Example 1

[0029] The dryer uses the MDTM series gas dryer of Bochun Co., Ltd., such as the model MD-110 gas dryer; the automatic flowmeter is the MFM / C series gas flowmeter of Aselte Instrument (Beijing) Co., Ltd., such as the model AST10-DLM gas flowmeter. The vacuum pump uses an acid- and alkali-resistant micro air pump. The peristaltic pump flow rate is 5mL / min. All flowmeters used are glass rotor flowmeters, the first flowmeter range is 100~300L / h, the second flowmeter range is 100~300L / h, and the third flowmeter range is 100~300mL / min. The alkali washing tank is filled with a KOH aqueous solution with a mass fraction of 25%, and the water washing tank is pure water; the average air extraction flow of the vacuum pump is 26L / min; the filtration accuracy of the filter is 1μm; the condenser is an electronic condenser with a processing capacity of 5L / min.

[0030] like Figure 1 As shown, a high-efficiency online analysis system for processing fluorine-containing gases is characterized in that it includes an alkali washing tank 1, a water washing tank 5, a vacuum pump 7, a cyclone separator 8, a condenser 11, a dryer 16, a gas chromatograph 21 and a water collecting tank 25. The aforementioned devices are connected in sequence through pipelines. The outlet pipeline of the cyclone separator 8 passes through the cyclone separator outlet three-way ball valve 10, one way is connected to the condenser 11, and the other way is connected to the condenser outlet three-way ball valve 13 and the second needle valve 15, and then goes to the exhaust gas treatment system; the water collecting tank 25 is connected to the fluorine-containing gas return system to form a loop.

[0031] A first flow meter 12 is installed on the outlet pipeline of the condenser 11 .

[0032] The dryer 16 is provided with a selective permeable membrane inside, which forms a sleeve structure with the outer wall. The inside of the membrane is a sample gas channel, and the outside of the membrane is a purge gas channel. The purge gas channel goes to the exhaust gas treatment system through the second flowmeter 18.

[0033] An automatic flow meter 19 and a filter 20 are installed on the pipeline connecting the dryer 16 and the gas chromatograph 21 .

[0034] A third flow meter 22 is installed at the outlet of the gas chromatograph 21 . The third flow meter 22 is connected to the fluorine-containing gas return system and is connected to the exhaust gas treatment system through a fourth needle valve 23 .

[0035] A first needle valve 9 is installed at the bottom of the cyclone separator 8, and then connected to the fluorine-containing gas return system. A peristaltic pump 14 is installed at the bottom of the condenser 11, and then connected to the fluorine-containing gas return system. A third needle valve 17 is installed at the bottom of the dryer 16, and then connected to the fluorine-containing gas return system.

[0036] The alkali washing tank 1 is equipped with an alkali washing vent valve 2, and an alkali washing three-way ball valve 3 is installed at the bottom of the alkali washing tank 1, and then goes to the waste liquid tank; the water washing tank 5 is equipped with a water washing vent valve 4, and a water washing three-way ball valve 6 is installed at the bottom of the water washing tank 5, and then goes to the waste liquid tank. Furthermore, a fifth needle valve 24 is installed on the pipeline connecting the water collecting tank 25 and the fluorine-containing gas return system.

[0037] A drain ball valve 26 is installed at the bottom of the water collecting tank 25, and then the water goes to the waste liquid tank.

[0038] The pipelines for fluorine-containing gases are made of polytetrafluoroethylene; the material selected for nitrogen pipelines is stainless steel pipelines with electropolished inner walls (EP grade).

[0039] This embodiment adopts primary alkali washing and primary water washing. Both the alkali washing tank 1 and the water washing tank 5 are made of hard polyvinyl chloride, with a volume of 140L. Spherical plastic fillers are installed inside. The alkali washing vent valve 2 and the water washing vent valve 4 are used for pressure relief and fluid replenishment. The alkali washing three-way ball valve 3 and the water washing three-way ball valve 6 have both sampling and drainage functions to ensure that the solution concentration is within the control range. The water collecting tank 25 is made of stainless steel, and the drainage ball valve 26 is used to drain the return air system.

[0040] Working process:

[0041] After connecting the fluorine-containing gas inlet pipeline to the inlet of the alkaline cleaning tank 1, open the condenser 11 and the peristaltic pump 14, pre-cool for 20 minutes, wait for the condenser 11 to cool to below 5°C, turn on the vacuum pump 7 and the dry back-blowing nitrogen of the dryer 16 in turn, and the sample gas passes through the vacuum pump 7 at a flow rate of 10 to 15 L / min, and then passes through the cyclone separator 8, the condenser 11 and the first flow meter 12 in turn at a flow rate of 2 to 5 L / min; the lower part of the cyclone separator 8 goes to the return air system through the first needle valve 9, and the peristaltic pump 14 provides power for the condensation and drainage process, with a rotation speed of 10 rpm; the outlet of the first flow meter 12 is connected to the condensation system through the first needle valve 9, and the peristaltic pump 14 provides power for the condensation and drainage process, with a rotation speed of 10 rpm; the outlet of the first flow meter 12 is connected to the condensation system through the first needle valve 9, and the peristaltic pump 14 provides power for the condensation and drainage process, with a rotation speed of 10 rpm; the outlet of the first flow meter 12 is connected to the condensation system through the first needle valve 9, and the peristaltic pump 14 provides power for the condensation and drainage process, and the rotation speed is ... The second needle valve 15 goes to the waste gas treatment system, and the other way passes through the dryer 16, the automatic flowmeter 19, the filter 20, the gas chromatograph 21 and the third flowmeter 22 in sequence at a flow rate of 20-60 mL / min, and then goes to the waste gas treatment system through the fourth needle valve 23 and the return gas system; the dry nitrogen is used as the dry backflush gas of the dryer 16, and goes to the return gas system through the third needle valve 17. The backflush nitrogen outlet goes to the waste gas treatment section through the second flowmeter 18. The flow direction of nitrogen and fluorine-containing gas is opposite. The gas chromatograph 21 is set to program automatic sampling and online continuous sampling analysis.

[0042] In this embodiment, when the analysis results are abnormal, the first needle valve 9, the third needle valve 17 and the fifth needle valve 24 are closed, the second needle valve 15 and the fourth needle valve 23 are opened, and the flow of the first flow meter 12 and the third flow meter 22 is controlled by adjusting their openings, and the replacement gas is quickly switched to the exhaust gas treatment system to avoid pollution.

[0043] The description of the embodiments of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and design various embodiments with various modifications suitable for specific purposes.

Claims

1. An efficient online analysis system for processing fluorine-containing gases, characterized in that: The invention comprises an alkali washing tank (1), a water washing tank (5), a vacuum pump (7), a cyclone separator (8), a condenser (11), a dryer (16), a gas chromatograph (21) and a water collecting tank (25), which are connected in sequence through pipelines. The outlet pipeline of the cyclone separator (8) passes through a three-way ball valve (10) at the outlet of the cyclone separator, one way of which is connected to the condenser (11), and the other way of which is connected to the three-way ball valve (13) at the outlet of the condenser and a second needle valve (15), and then goes to the waste gas treatment system; the water collecting tank (25) is connected to a fluorine-containing gas return system to form a loop.

2. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: A first flow meter (12) is installed on the outlet pipeline of the condenser (11).

3. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: The (16) is internally provided with a selective permeable membrane, which forms a sleeve structure with the outer wall. The inside of the membrane is a sample gas channel, and the outside of the membrane is a purge gas channel. The purge gas channel passes through the second flow meter (18) to the exhaust gas treatment system.

4. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: An automatic flow meter (19) and a filter (20) are installed on the pipeline connecting the dryer (16) and the gas chromatograph (21).

5. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: A third flow meter (22) is installed at the outlet of the gas chromatograph (21), and the third flow meter (22) is connected to the fluorine-containing gas return system and is connected to the exhaust gas treatment system through a fourth needle valve (23).

6. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that the cyclone A first needle valve (9) is installed at the bottom of the separator (8), and then connected to the fluorine-containing gas return system; a peristaltic pump (14) is installed at the bottom of the condenser (11), and then connected to the fluorine-containing gas return system; a third needle valve (17) is installed at the bottom of the dryer (16), and then connected to the fluorine-containing gas return system.

7. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: An alkali washing drain valve (2) is installed on the alkali washing tank (1), and an alkali washing three-way ball valve (3) is installed at the bottom of the alkali washing tank (1), and then the waste liquid tank is discharged; a water washing drain valve (4) is installed on the water washing tank (5), and a water washing three-way ball valve (6) is installed at the bottom of the water washing tank (5), and then the waste liquid tank is discharged; a drain ball valve (26) is installed at the bottom of the water collecting tank (25), and then the waste liquid tank is discharged.

8. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: A fifth needle valve (24) is installed on the pipeline connecting the water collecting tank (25) and the fluorine-containing gas return system.

9. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: The condenser is an electronic condenser; the condenser flow rate is 0-10L / min; the peristaltic pump flow rate is 5mL / min; the first flow meter range is 100-300L / h; the second flow meter range is 100-300L / h; the third flow meter range is 100-300mL / min; the flow meter is a glass rotor flow meter, a metal rotor flow meter or a gas turbine flow meter; the vacuum pump is an acid and alkali resistant micro air pump; the filter pore size is ≤1μm.

10. The high-efficiency online analysis system for processing fluorine-containing gases according to claim 1 is characterized in that: The material of the pipeline through which the fluorine-containing gas flows is selected from polytetrafluoroethylene, stainless steel, polytrifluoroethylene or tetrafluoroethylene-perfluoroalkoxy vinyl ether polymer; the material of the alkali washing tank and the water washing tank is selected from polytetrafluoroethylene or stainless steel, and is one-stage or multi-stage, with acid and alkali resistant fillers inside; the material of the cyclone separator and the water collecting tank is selected from stainless steel or carbon steel.

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