A C4F7N / CO2 mixed gas purification system and method

Abstract

The application discloses a C4F7N / CO2 mixed gas purification treatment system and method, belongs to the field of insulating gas treatment, and is used for purifying and recycling low-concentration C4F7N mixed gas on site; a filter adsorption device output is connected with a preheating pressure stabilizing pipeline input, the preheating pressure stabilizing pipeline output is connected with an organic membrane separation device module input, the organic membrane separation device module first output is connected with a rectification and purification device input, the organic membrane separation device module second output is connected with a tail gas treatment device input, the tail gas treatment device first output is connected between the filter adsorption device and the preheating pressure stabilizing pipeline, the tail gas treatment device second output is used as a vent, the rectification and purification device first output is connected with a filling pipeline input, the rectification and purification device second output is connected between the filter adsorption device and the preheating pressure stabilizing pipeline, the filling pipeline first output is connected between the organic membrane separation device module and the rectification and purification device, and the filling pipeline second output is used as a system output; the treatment efficiency is high, and the energy consumption is low.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment insulating gas treatment technology, and relates to a C4F7N / CO2 mixed gas purification treatment system and method. Background Technology

[0002] Sulfur hexafluoride (SF6) gas possesses excellent insulation and arc-extinguishing properties, and SF6 electrical equipment has become a core component of urban power supply and ultra-high voltage power transmission and transformation equipment. However, it has a strong greenhouse effect and has been banned and restricted internationally. Therefore, there is an urgent need to develop new environmentally friendly insulating gases to completely replace the greenhouse gas SF6 in power grids.

[0003] Perfluoroisobutyronitrile (C4F7N) is currently the most promising known alternative to SF6 gas and has been widely adopted in power grids. Due to its high liquefaction temperature, C4F7N gas needs to be mixed with CO2 when used in electrical equipment. After use, the C4F7N / CO2 mixture requires recycling and treatment. With the large-scale application of C4F7N, the recycling and treatment of C4F7N gas is becoming increasingly important.

[0004] When C4F7N / CO2 mixed gas is used as an insulating medium in the power industry, the concentration of C4F7N in the mixed gas is less than 15%, and the general usage concentration range is 5% to 12%. Within this range, the insulation strength of the mixed gas is relatively low compared to the main insulating medium (C4F7N) in pure SF6 gas. Conventional gas separation and purification methods cannot effectively separate and purify the mixed gas. Therefore, the concentration of C4F7N in the mixed gas recovered on-site is about 10%. Due to the low proportion of the main insulating medium (C4F7N) in the mixed gas, conventional gas separation and purification methods cannot effectively separate and purify the mixed gas.

[0005] In the prior art, the application published on August 24, 2021, with application number CN113294969A, entitled "A Separation Device and Method for Perfluoroisobutyronitrile and Carbon Dioxide Mixed Gas", proposes a two-stage distillation method. However, this method has the following disadvantages: 1) Low-temperature distillation is suitable for the separation and purification of high-concentration target substances, but it has poor separation effect for low-concentration mixed gases and is not suitable for the treatment of C4F7N / CO2 mixed gases recovered on site; 2) The two-stage distillation method has high energy consumption when treating low-concentration mixed gases; 3) Some decomposition products may be generated during the operation of the equipment, and a large amount of water may be mixed in. Since the liquefaction temperatures of water and C4F7N are 0℃ and -4.7℃, respectively, direct low-temperature distillation of C4F7N / CO2 mixed gas will cause water to liquefy together with C4F7N, resulting in poor treatment efficiency. Summary of the Invention

[0006] The purpose of this invention is to design a C4F7N / CO2 mixed gas purification system to solve the problem of poor separation effect caused by the low concentration of C4F7N in the C4F7N / CO2 mixed gas recovered on site.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0008] A C4F7N / CO2 mixed gas purification system includes: a filter adsorption device (11), a preheating and stabilizing pipeline (12), an organic membrane separation device module (13), a tail gas treatment device (14), a distillation and purification device (15), and a filling pipeline (16); the output end of the filter adsorption device (11) is sealed to the input end of the preheating and stabilizing pipeline (12), the output end of the preheating and stabilizing pipeline (12) is sealed to the input end of the organic membrane separation device module (13), the first output end of the organic membrane separation device module (13) is sealed to the input end of the distillation and purification device (15), and the second output end of the organic membrane separation device module (13) is sealed to the input end of the tail gas treatment device (14). The input end of the tail gas treatment device (14) is sealed and connected. The first output end of the tail gas treatment device (14) is sealed and connected between the filter adsorption device (11) and the preheating and stabilizing pipeline (12). The second output end of the tail gas treatment device (14) serves as the system's vent. The first output end of the distillation and purification device (15) is sealed and connected to the input end of the filling pipeline (16). The second output end of the distillation and purification device (15) is sealed and connected between the filter adsorption device (11) and the preheating and stabilizing pipeline (12). The first output end of the filling pipeline (16) is sealed and connected between the organic membrane separation device module (13) and the distillation and purification device (15). The second output end of the filling pipeline (16) serves as the system's output end.

[0009] Further, the filter adsorption device (11) includes: a first pressure sensor (P1), a first solenoid valve (V1), a first-stage filter adsorption device (111), a second-stage filter adsorption device (112), a third-stage filter adsorption device (113), a pressure reducing valve (JY), and a second solenoid valve (V2); one end of the first solenoid valve (V1) is sealed to the air inlet, and the other end of the first solenoid valve (V1) is sealed to the bottom input end of the first-stage filter adsorption device (111). The top output end of 11) is sealed to the bottom input end of the second-stage filtration adsorption device (112), the top output end of the second-stage filtration adsorption device (112) is sealed to the bottom input end of the third-stage filtration adsorption device (113), the top output end of the third-stage filtration adsorption device (113) is sealed to one end of the pressure reducing valve (JY), the other end of the pressure reducing valve (JY) is sealed to one end of the second solenoid valve (V2), and the first pressure sensor (P1) is sealed between the air inlet and the first solenoid valve (V1).

[0010] Further, the preheating and stabilizing pipeline (12) includes: a first electromagnetic proportional regulating valve (VT1), a first compressor (K1), a first check valve (121), a first heat exchanger (122), a pressure control device (123), a first temporary storage tank (124), a second pressure sensor (P2), a first temperature sensor (T1), and a gas heater (125); one end of the first electromagnetic proportional regulating valve (VT1) is sealed to the other end of the second electromagnetic valve (V2), and the other end of the first electromagnetic proportional regulating valve (VT1) is sealed to the input end of the first compressor (K1), and the output of the first compressor (K1) is... The output end is sealed to the input end of the first one-way valve (121), the output end of the first one-way valve (121) is sealed to the input end of the first heat exchanger (122), the output end of the first heat exchanger (122) is sealed to the input end of the first temporary storage tank (124), the output end of the first temporary storage tank (124) is sealed to the input end of the gas heater (125), the pressure control device (123) is sealed between the first heat exchanger (122) and the first temporary storage tank (124), and the second pressure sensor (P2) and the first temperature sensor (T1) are both sealed to the top of the first temporary storage tank (124).

[0011] Further, the organic membrane separation device module (13) includes: a third solenoid valve (V3), an organic membrane separation device (131), a gas purity sampling device (132), a fourth solenoid valve (V4), a fifth solenoid valve (V5), a second temporary storage tank (133), and a third pressure sensor (P3); one end of the third solenoid valve (V3) is sealed to the output end of the gas heater (125), and the other end of the third solenoid valve (V3) is sealed to the top input end of the organic membrane separation device (131); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4); the third solenoid valve (V5) of the organic membrane separation device (131) is sealed to the first output end of the fourth solenoid valve (V4). One output end is used to discharge the tail gas separated by the organic membrane separation device (131). The second output end of the organic membrane separation device (131) is sealed to one end of the fifth solenoid valve (V5). The second output end of the organic membrane separation device (131) is used to output the finished gas separated by the organic membrane separation device (131). The other end of the fifth solenoid valve (V5) is sealed to the top input end of the second temporary storage tank (133). The gas purity sampling device (132) is sealed between the second output end of the organic membrane separation device (131) and the fifth solenoid valve (V5). The third pressure sensor (P3) is sealed to the top of the second temporary storage tank (133).

[0012] Further, the exhaust gas treatment device (14) includes: a second compressor (K2), a sixth solenoid valve (V6), a seventh solenoid valve (V7), an eighth solenoid valve (V8), a ninth solenoid valve (V9), a tenth solenoid valve (V10), an eleventh solenoid valve (V11), a first pipeline filter (141), a second pipeline filter (142), a first adsorption tower (143), a second adsorption tower (144), a second electromagnetic proportional regulating valve (VT2), an exhaust sampling device (145), and a fourth pressure sensor (P4); the input end of the second compressor (K2) is connected to the other end of the fourth solenoid valve (V4). A sealed connection is established, with one end of the sixth solenoid valve (V6) sealed to the output end of the second compressor (K2), and the other end of the sixth solenoid valve (V6) sealed to the input end of the first pipeline filter (141). The output end of the first pipeline filter (141) is sealed to the input end of the first adsorption tower (143), and the output end of the first adsorption tower (143) is sealed to one end of the eighth solenoid valve (V8). The other end of the eighth solenoid valve (V8) is sealed to one end of the second electromagnetic proportional regulating valve (VT2), and the other end of the second electromagnetic proportional regulating valve (VT2) is sealed to the vent. The seventh solenoid valve... One end of the solenoid valve (V7) is sealed between the sixth solenoid valve (V6) and the first pipeline filter (141), and the other end of the seventh solenoid valve (V7) is sealed between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). One end of the ninth solenoid valve (V9) is sealed to the output end of the second compressor (K2), and the other end of the ninth solenoid valve (V9) is sealed to the input end of the second pipeline filter (142). The output end of the second pipeline filter (142) is sealed to the input end of the second adsorption tower (144), and the output end of the second adsorption tower (144) is sealed to the eleventh solenoid valve (V7). One end of the eleventh solenoid valve (V11) is sealed and connected, and the other end of the eleventh solenoid valve (V11) is sealed and connected to one end of the second electromagnetic proportional regulating valve (VT2). One end of the tenth solenoid valve (V10) is sealed and connected between the ninth solenoid valve (V9) and the second pipeline filter (142). The other end of the tenth solenoid valve (V10) is sealed and connected between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). The first adsorption tower (143) and the second adsorption tower (144) are backups for each other. When one of the adsorption towers is saturated, the other adsorption tower is started to adsorb. The saturated adsorption tower is desorbed.

[0013] Further, the distillation and purification apparatus (15) includes: a third compressor (K3), a second heat exchanger (151), a first manual valve (ST1), a distillation column (152), a refrigerator (153), a twelfth solenoid valve (V12), a thirteenth solenoid valve (V13), a third temporary storage tank (154), a fifth pressure sensor (P5), a third electromagnetic proportional regulating valve (VT3), and a second check valve (155); the input end of the third compressor (K3) is sealed to the output end of the second temporary storage tank (133), the output end of the third compressor (K3) is sealed to the top input end of the second heat exchanger (151), the bottom output end of the second heat exchanger (151) is sealed to one end of the first manual valve (ST1), and the other end of the first manual valve (ST1) is sealed to the bottom of the distillation column (152). The top input end of the third temporary storage tank (154) is sealed and connected. The top of the distillation column (152) is sealed and connected to one end of the third electromagnetic proportional control valve (VT3). The other end of the third electromagnetic proportional control valve (VT3) is sealed and connected to the input end of the second one-way valve (155). The output end of the second one-way valve (155) is sealed and connected between the second electromagnetic valve (V2) and the first electromagnetic proportional control valve (VT1). The input end of the refrigerator (153) is sealed and connected to the distillation column (152) and the second heat exchanger (151) respectively. The output end of the refrigerator (153) is sealed and connected to one end of the twelfth electromagnetic valve (V12) and the thirteenth electromagnetic valve (V13) respectively. The other end of the twelfth electromagnetic valve (V12) is sealed and connected to the second heat exchanger (151). The other end of the thirteenth electromagnetic valve (V13) is sealed and connected to the distillation column (152).

[0014] Further, the filling pipeline (16) includes: a second manual valve (ST2), a fourth compressor (K4), a fourteenth solenoid valve (V14), a fifteenth solenoid valve (V15), a third check valve (161), and a sixth pressure sensor (P6); the bottom output end of the third temporary storage tank (154) is sealed to one end of the second manual valve (ST2), the other end of the second manual valve (ST2) is sealed to one end of the fifteenth solenoid valve (V15), and the other end of the fifteenth solenoid valve (V15) is sealed to the fourth compressor (K4). 4) The input end of the compressor (K4) is sealed and connected. The output end of the compressor (K4) is sealed and connected to the input end of the third check valve (161). The output end of the third check valve (161) is sealed and connected to the filling port. One end of the fourteenth solenoid valve (V14) is sealed and connected between the second storage tank (133) and the third compressor (K3). The other end of the fourteenth solenoid valve (V14) is sealed and connected between the third check valve (161) and the filling port. The sixth pressure sensor (P6) is sealed and installed between the third check valve (161) and the filling port.

[0015] Furthermore, the first-stage filtration and adsorption device (111) is filled with porous metal filter material to remove dust from the mixed gas; the second-stage filtration and adsorption device (112) is filled with 5A molecular sieve and silica gel adsorbent to remove moisture from the mixed gas; and the third-stage filtration and adsorption device (113) is filled with metal-organic framework material to selectively adsorb CF3CN, CNCN, and C2F5CN impurity components from the mixed gas.

[0016] Furthermore, the metal-organic framework material is prepared by reacting 1,10-phenanthroline with sodium benzoate and copper sulfate; its molecular formula is C0. 26 H 18 Cu1N2O4 belongs to the orthorhombic crystal system, space group Fdd2, with the following cell parameters: a=41.156(3)Å, b=5.6892(4)Å, c=18.3043(16)Å, α=90°, β=108.502(2)°, γ=90°, and a cell volume of 4285.8(6)Å. 3 .

[0017] Further, the preparation method of the metal-organic framework material includes the following steps: dissolving sodium benzoate, copper sulfate, and 1,10-o-phenanthroline in a mixed solution of water and methanol to obtain a reaction solution; placing the reaction solution in a hydrothermal reactor for reaction, and cooling to room temperature to obtain the metal-organic framework material; the molar ratio of sodium benzoate, copper sulfate, and 1,10-o-phenanthroline is 1-3:1-3:1; the volume ratio of water to methanol in the mixed solution of water and methanol is 1:1; the concentration of 1,10-o-phenanthroline in the reaction solution is 0.04 mmol / ml; the reaction temperature in the hydrothermal reactor is 140-180℃, and the time is 24-48 h.

[0018] A purification method for the C4F7N / CO2 mixed gas purification system includes the following steps:

[0019] SS1. The input C4F7N / CO2 mixed gas is filtered and purified using a filter adsorption device (11);

[0020] SS2. Turn on the preheating and pressure stabilizing pipeline (12) to heat and pressurize the C4F7N / CO2 mixed gas;

[0021] SS3. The organic membrane separation device module (13) is used to separate C4F7N and CO2 in the C4F7N / CO2 mixed gas and enrich the C4F7N gas.

[0022] SS4. The CO2 and C4F7N mixed exhaust gas separated by the organic membrane separation device module (13) is input into the exhaust gas treatment device (14) for treatment;

[0023] SS5. Start the distillation and purification unit (15) to distill and purify the enriched C4F7N / CO2 mixed gas;

[0024] SS6. The liquid C4F7N purified by distillation in the distillation purification device (15) is filled using the filling pipeline (16).

[0025] Further, the filtration and adsorption device (11) includes: a first solenoid valve (V1), a first-stage filtration and adsorption device (111), a second-stage filtration and adsorption device (112), a third-stage filtration and adsorption device (113), a pressure reducing valve (JY), and a second solenoid valve (V2); one end of the first solenoid valve (V1) is sealed to the air inlet, and the other end of the first solenoid valve (V1) is sealed to the bottom input end of the first-stage filtration and adsorption device (111), and the top of the first-stage filtration and adsorption device (111) is sealed to the air inlet. The output end of the first stage is sealed to the bottom input end of the second stage filtration adsorption device (112), the top output end of the second stage filtration adsorption device (112) is sealed to the bottom input end of the third stage filtration adsorption device (113), the top output end of the third stage filtration adsorption device (113) is sealed to one end of the pressure reducing valve (JY), the other end of the pressure reducing valve (JY) is sealed to one end of the second solenoid valve (V2), and the other end of the second solenoid valve (V2) is sealed to the preheating pressure stabilizing pipeline (12).

[0026] The method of using a filter adsorption device (11) to filter and purify the input C4F7N / CO2 mixed gas in step SS1 is as follows: Open the first solenoid valve (V1), and the input C4F7N / CO2 mixed gas passes through the first stage filter adsorption device (111), the second stage filter adsorption device (112), and the third stage filter adsorption device (113) in sequence for filtration and purification. The filtered and purified mixed gas then passes through the pressure reducing valve (JY) and the second solenoid valve (V2) in sequence into the preheating and stabilizing pipeline (12).

[0027] Further, the preheating and stabilizing pipeline (12) includes: a first electromagnetic proportional regulating valve (VT1), a first compressor (K1), a first check valve (121), a first heat exchanger (122), a pressure control device (123), a first temporary storage tank (124), a second pressure sensor (P2), a first temperature sensor (T1), and a gas heater (125); one end of the first electromagnetic proportional regulating valve (VT1) is sealed to the other end of the second electromagnetic valve (V2), and the other end of the first electromagnetic proportional regulating valve (VT1) is sealed to the input end of the first compressor (K1), and the output of the first compressor (K1) is... The output end is sealed to the input end of the first one-way valve (121), the output end of the first one-way valve (121) is sealed to the input end of the first heat exchanger (122), the output end of the first heat exchanger (122) is sealed to the input end of the first temporary storage tank (124), the output end of the first temporary storage tank (124) is sealed to the input end of the gas heater (125), the pressure control device (123) is sealed between the first heat exchanger (122) and the first temporary storage tank (124), and the second pressure sensor (P2) and the first temperature sensor (T1) are both sealed to the top of the first temporary storage tank (124).

[0028] The method for heating and pressurizing the C4F7N / CO2 mixed gas by opening the preheating and pressure stabilizing pipeline (12) in step SS2 is as follows: open the first electromagnetic proportional regulating valve (VT1), turn on the first compressor (K1), the first heat exchanger (122), and the gas heater (125) to heat and pressurize the filtered and purified mixed gas, so that the temperature and pressure of the mixed gas in the first temporary storage tank (124) are maintained at 40℃~55℃ and 0.7MPa~1.0MPa.

[0029] Further, the organic membrane separation device module (13) includes: a third solenoid valve (V3), an organic membrane separation device (131), a gas purity sampling device (132), a fourth solenoid valve (V4), a fifth solenoid valve (V5), a second temporary storage tank (133), and a third pressure sensor (P3); one end of the third solenoid valve (V3) is sealed to the output end of the gas heater (125), and the other end of the third solenoid valve (V3) is sealed to the top input end of the organic membrane separation device (131); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4); the third solenoid valve (V5) of the organic membrane separation device (131) is sealed to the first output end of the fourth solenoid valve (V4). One output end is used to discharge the tail gas separated by the organic membrane separation device (131). The second output end of the organic membrane separation device (131) is sealed to one end of the fifth solenoid valve (V5). The second output end of the organic membrane separation device (131) is used to output the finished gas separated by the organic membrane separation device (131). The other end of the fifth solenoid valve (V5) is sealed to the top input end of the second temporary storage tank (133). The gas purity sampling device (132) is sealed between the second output end of the organic membrane separation device (131) and the fifth solenoid valve (V5). The third pressure sensor (P3) is sealed to the top of the second temporary storage tank (133).

[0030] The method described in step SS3 for separating C4F7N and CO2 in the C4F7N / CO2 mixed gas using an organic membrane separation device module (13) and enriching C4F7N gas is as follows: the third solenoid valve (V3) is opened, the mixed gas enters the organic membrane separation device module (13) for separation, the separated finished gas passes through the fifth solenoid valve (V5) and is stored in the second temporary storage tank (133), and the separated tail gas passes through the fourth solenoid valve (V4) and enters the tail gas treatment device (14) for treatment;

[0031] Further, the exhaust gas treatment device (14) includes: a second compressor (K2), a sixth solenoid valve (V6), a seventh solenoid valve (V7), an eighth solenoid valve (V8), a ninth solenoid valve (V9), a tenth solenoid valve (V10), an eleventh solenoid valve (V11), a first pipeline filter (141), a second pipeline filter (142), a first adsorption tower (143), a second adsorption tower (144), a second electromagnetic proportional regulating valve (VT2), an exhaust sampling device (145), and a fourth pressure sensor (P4); the second compressor (K2) The input end of the sixth solenoid valve (V6) is sealed to the other end of the fourth solenoid valve (V4). One end of the sixth solenoid valve (V6) is sealed to the output end of the second compressor (K2). The other end of the sixth solenoid valve (V6) is sealed to the input end of the first pipeline filter (141). The output end of the first pipeline filter (141) is sealed to the input end of the first adsorption tower (143). The output end of the first adsorption tower (143) is sealed to one end of the eighth solenoid valve (V8). The other end of the eighth solenoid valve (V8) is sealed to one end of the second electromagnetic proportional regulating valve (VT2). The other end of the second electromagnetic proportional regulating valve (VT2) is sealed to the vent port. One end of the seventh electromagnetic valve (V7) is sealed between the sixth electromagnetic valve (V6) and the first pipeline filter (141), and the other end of the seventh electromagnetic valve (V7) is sealed between the second electromagnetic valve (V2) and the first electromagnetic proportional regulating valve (VT1). One end of the ninth electromagnetic valve (V9) is sealed to the output end of the second compressor (K2), and the other end of the ninth electromagnetic valve (V9) is sealed to the input end of the second pipeline filter (142). The output end of the device (142) is sealed to the input end of the second adsorption tower (144), the output end of the second adsorption tower (144) is sealed to one end of the eleventh solenoid valve (V11), the other end of the eleventh solenoid valve (V11) is sealed to one end of the second electromagnetic proportional regulating valve (VT2), one end of the tenth solenoid valve (V10) is sealed between the ninth solenoid valve (V9) and the second pipeline filter (142), and the other end of the tenth solenoid valve (V10) is sealed between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1).

[0032] The specific method for inputting the mixed CO2 and C4F7N tail gas separated by the organic membrane separation device module (13) into the tail gas treatment device (14) for treatment in step SS4 is as follows: Open the fourth solenoid valve (V4), the sixth solenoid valve (V6), and the eighth solenoid valve (V8), and start the second compressor (K2). The tail gas separated by the organic membrane separation device module (13) passes through the fourth solenoid valve (V4), the sixth solenoid valve (V6), and the first pipeline filter (141) into the first adsorption tower (143). The first adsorption tower (143) adsorbs the C4F7N in the tail gas, and the remaining CO2 and C4F7N are then adsorbed. CO2 gas is discharged through the eighth solenoid valve (V8) and the second electromagnetic proportional regulating valve (VT2). When the first adsorption tower (143) is saturated, the sixth solenoid valve (V6) and the eighth solenoid valve (V8) are closed, and the ninth solenoid valve (V9) and the eleventh solenoid valve (V11) are opened. The second adsorption tower (144) adsorbs C4F7N in the tail gas. At this time, the seventh solenoid valve (V7), the first electromagnetic proportional regulating valve (VT1), and the first compressor (K1) are opened to perform negative pressure desorption on the first adsorption tower (143), so that the first adsorption tower (143) can resume its adsorption function.

[0033] Further, the distillation and purification apparatus (15) includes: a third compressor (K3), a second heat exchanger (151), a first manual valve (ST1), a distillation column (152), a refrigerator (153), a twelfth solenoid valve (V12), a thirteenth solenoid valve (V13), a third temporary storage tank (154), a fifth pressure sensor (P5), a third electromagnetic proportional regulating valve (VT3), and a second check valve (155); the input end of the third compressor (K3) is sealed to the output end of the second temporary storage tank (133), the output end of the third compressor (K3) is sealed to the top input end of the second heat exchanger (151), the bottom output end of the second heat exchanger (151) is sealed to one end of the first manual valve (ST1), and the other end of the first manual valve (ST1) is sealed to the bottom of the distillation column (152). The top input end of the third temporary storage tank (154) is sealed and connected. The top of the distillation column (152) is sealed and connected to one end of the third electromagnetic proportional control valve (VT3). The other end of the third electromagnetic proportional control valve (VT3) is sealed and connected to the input end of the second one-way valve (155). The output end of the second one-way valve (155) is sealed and connected between the second electromagnetic valve (V2) and the first electromagnetic proportional control valve (VT1). The input end of the refrigerator (153) is sealed and connected to the distillation column (152) and the second heat exchanger (151) respectively. The output end of the refrigerator (153) is sealed and connected to one end of the twelfth electromagnetic valve (V12) and the thirteenth electromagnetic valve (V13) respectively. The other end of the twelfth electromagnetic valve (V12) is sealed and connected to the second heat exchanger (151). The other end of the thirteenth electromagnetic valve (V13) is sealed and connected to the distillation column (152).

[0034] The specific method for purifying the enriched C4F7N / CO2 mixed gas by starting the distillation purification device (15) as described in step SS5 is as follows:

[0035] The third compressor (K3) is turned on, and the first manual valve (ST1) is opened. The mixed gas in the second temporary storage tank (133) is input into the second heat exchanger (151) for preliminary cooling. The preliminarily cooled mixed gas then enters the distillation column (152) after passing through the first manual valve (ST1). The refrigerator (153) and the thirteenth solenoid valve (V13) are turned on. The refrigerator (153) cools the distillation column (152). The high concentration of the mixed gas in the distillation column (152) is due to... The C4F7N in the mixed gas is liquefied by cooling and pressurizing. The CO2 in the mixed gas is still in a gaseous state due to the low liquefaction temperature. The liquefied C4F7N is collected in the third temporary storage tank (154) at the bottom of the distillation column (152). The unliquefied CO2 gas and a small amount of C4F7N gas are discharged through the top of the distillation column (152). The discharged gas is returned to the preheating and pressure stabilizing pipeline (12) for circulation through the third electromagnetic proportional regulating valve (VT3) and the second one-way valve (155).

[0036] Further, the filling pipeline (16) includes: a second manual valve (ST2), a fourth compressor (K4), a fourteenth solenoid valve (V14), a fifteenth solenoid valve (V15), a third check valve (161), and a sixth pressure sensor (P6); the bottom output end of the third temporary storage tank (154) is sealed to one end of the second manual valve (ST2), the other end of the second manual valve (ST2) is sealed to one end of the fifteenth solenoid valve (V15), and the other end of the fifteenth solenoid valve (V15) is sealed to the fourth compressor (K4). 4) The input end of the fourth compressor (K4) is sealed and connected to the input end of the third check valve (161). The output end of the third check valve (161) is sealed and connected to the filling port. One end of the fourteenth solenoid valve (V14) is sealed and connected between the second temporary storage tank (133) and the third compressor (K3). The other end of the fourteenth solenoid valve (V14) is sealed and connected between the third check valve (161) and the filling port. The sixth pressure sensor (P6) is sealed and installed between the third check valve (161) and the filling port.

[0037] The method described in step SS6 for filling the liquid C4F7N purified by distillation in the distillation purification device (15) using the filling pipeline (16) is as follows: open the second manual valve (ST2) and the fifteenth solenoid valve (V15), turn on the fourth compressor (K4) to fill the liquid C4F7N in the third temporary storage tank (154) into the steel cylinder. After filling, close the second manual valve (ST2), turn on the fourteenth solenoid valve (V14) and the third compressor (K3) to recover the remaining liquid C4F7N in the pipeline.

[0038] The advantages of this invention are:

[0039] (1) The system of the present invention first uses a filter adsorption device (11) to filter out dust, moisture and impurity components in the mixed gas, and then uses an organic membrane separation device module (13) to enrich the C4F7N component in the mixed gas to obtain a high concentration of C4F7N insulating gas. Then, it uses a distillation purification device (15) for further purification. A preheating and pressure stabilizing pipeline (12) is set up to heat and pressurize the filtered and purified mixed gas, so that the temperature and pressure of the mixed gas are maintained at 40℃~55℃ and 0.7MPa~1.0MPa, which improves the separation efficiency of the mixed gas. The system of the present invention is suitable for the purification treatment of C4F7N / CO2 mixed gas recovered on site. The system has high processing efficiency and low energy consumption.

[0040] (2) Two adsorption towers are set in the exhaust gas treatment device (14). The first adsorption tower (143) and the second adsorption tower (144) are backups for each other. When one of the adsorption towers is saturated, the other adsorption tower is turned on, so that the exhaust gas can be treated continuously, which improves the efficiency of exhaust gas treatment.

[0041] (3) The metal-organic framework material of the present invention is prepared by reacting 1,10-o-phenanthroline with sodium benzoate and copper sulfate as raw materials to prepare a novel metal-organic framework material. The metal-organic framework material and the adsorbent prepared with it as a precursor have a complex and controllable pore structure and a strong charge adsorption capacity. Both the metal-organic framework material and the prepared adsorbent show excellent selectivity for the adsorption of perfluoroisobutyronitrile gas impurities, and are the best choice for pretreatment of C4F7N mixed gas. Attached Figure Description

[0042] Figure 1 This is a structural block diagram of the C4F7N / CO2 mixed gas purification system of the present invention;

[0043] Figure 2 This is a detailed structural diagram of the C4F7N / CO2 mixed gas purification system of the present invention.

[0044] Figure 3 This is a flowchart of the C4F7N / CO2 mixed gas purification system of the present invention;

[0045] Figure 4 The molecular structural formula of the metal-organic framework material of the present invention is shown below;

[0046] Figure 5 This is a cell packing diagram of the metal-organic framework material of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0049] Example 1

[0050] like Figure 1 and Figure 2 As shown, a C4F7N / CO2 mixed gas purification system includes: a filter adsorption device (11), a preheating and pressure stabilizing pipeline (12), an organic membrane separation device module (13), a tail gas treatment device (14), a distillation and purification device (15), and a filling pipeline (16).

[0051] The filter adsorption device (11) includes: a first pressure sensor (P1), a first solenoid valve (V1), a first-stage filter adsorption device (111), a second-stage filter adsorption device (112), a third-stage filter adsorption device (113), a pressure reducing valve (JY), and a second solenoid valve (V2); one end of the first solenoid valve (V1) is sealed to the air inlet, and the other end of the first solenoid valve (V1) is sealed to the bottom input end of the first-stage filter adsorption device (111). The top output end of the device is sealed to the bottom input end of the second-stage filtration and adsorption device (112). The top output end of the second-stage filtration and adsorption device (112) is sealed to the bottom input end of the third-stage filtration and adsorption device (113). The top output end of the third-stage filtration and adsorption device (113) is sealed to one end of the pressure reducing valve (JY). The other end of the pressure reducing valve (JY) is sealed to one end of the second solenoid valve (V2). The first pressure sensor (P1) is sealed between the air inlet and the first solenoid valve (V1).

[0052] The first-stage filtration and adsorption device (111) is filled with porous metal filter material to remove dust from the mixed gas; the second-stage filtration and adsorption device (112) is filled with 5A molecular sieve and silica gel adsorbent to remove moisture from the mixed gas; and the third-stage filtration and adsorption device (113) is filled with metal-organic framework material to selectively adsorb impurity components such as CF3CN, CNCN, and C2F5CN from the mixed gas.

[0053] The preheating and stabilizing pipeline (12) includes: a first electromagnetic proportional regulating valve (VT1), a first compressor (K1), a first check valve (121), a first heat exchanger (122), a pressure control device (123), a first temporary storage tank (124), a second pressure sensor (P2), a first temperature sensor (T1), and a gas heater (125); one end of the first electromagnetic proportional regulating valve (VT1) is sealed to the other end of the second electromagnetic valve (V2), the other end of the first electromagnetic proportional regulating valve (VT1) is sealed to the input end of the first compressor (K1), and the output end of the first compressor (K1) is sealed to the input end of the first compressor (K1). The input end of the first one-way valve (121) is sealed and connected, the output end of the first one-way valve (121) is sealed and connected to the input end of the first heat exchanger (122), the output end of the first heat exchanger (122) is sealed and connected to the input end of the first temporary storage tank (124), the output end of the first temporary storage tank (124) is sealed and connected to the input end of the gas heater (125), the pressure control device (123) is sealed and installed between the first heat exchanger (122) and the first temporary storage tank (124), and the second pressure sensor (P2) and the first temperature sensor (T1) are both sealed and installed on the top of the first temporary storage tank (124).

[0054] The organic membrane separation device module (13) includes: a third solenoid valve (V3), an organic membrane separation device (131), a gas purity sampling device (132), a fourth solenoid valve (V4), a fifth solenoid valve (V5), a second temporary storage tank (133), and a third pressure sensor (P3); one end of the third solenoid valve (V3) is sealed to the output end of the gas heater (125), and the other end of the third solenoid valve (V3) is sealed to the top input end of the organic membrane separation device (131); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4). The second output end is used to discharge the tail gas separated by the organic membrane separation device (131). The second output end of the organic membrane separation device (131) is sealed to one end of the fifth solenoid valve (V5). The second output end of the organic membrane separation device (131) is used to output the finished gas separated by the organic membrane separation device (131). The other end of the fifth solenoid valve (V5) is sealed to the top input end of the second temporary storage tank (133). The gas purity sampling device (132) is sealed between the second output end of the organic membrane separation device (131) and the fifth solenoid valve (V5). The third pressure sensor (P3) is sealed to the top of the second temporary storage tank (133).

[0055] The exhaust gas treatment device (14) includes: a second compressor (K2), a sixth solenoid valve (V6), a seventh solenoid valve (V7), an eighth solenoid valve (V8), a ninth solenoid valve (V9), a tenth solenoid valve (V10), an eleventh solenoid valve (V11), a first pipeline filter (141), a second pipeline filter (142), a first adsorption tower (143), a second adsorption tower (144), a second electromagnetic proportional regulating valve (VT2), an exhaust sampling device (145), and a fourth pressure sensor (P4); the input end of the second compressor (K2) is sealed to the other end of the fourth solenoid valve (V4). Next, one end of the sixth solenoid valve (V6) is sealed to the output end of the second compressor (K2), and the other end of the sixth solenoid valve (V6) is sealed to the input end of the first pipeline filter (141). The output end of the first pipeline filter (141) is sealed to the input end of the first adsorption tower (143), and the output end of the first adsorption tower (143) is sealed to one end of the eighth solenoid valve (V8). The other end of the eighth solenoid valve (V8) is sealed to one end of the second electromagnetic proportional regulating valve (VT2), and the other end of the second electromagnetic proportional regulating valve (VT2) is sealed to the vent. The seventh solenoid valve... One end of the seventh solenoid valve (V7) is sealed between the sixth solenoid valve (V6) and the first pipeline filter (141). The other end of the seventh solenoid valve (V7) is sealed between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). One end of the ninth solenoid valve (V9) is sealed to the output end of the second compressor (K2), and the other end of the ninth solenoid valve (V9) is sealed to the input end of the second pipeline filter (142). The output end of the second pipeline filter (142) is sealed to the input end of the second adsorption tower (144), and the output end of the second adsorption tower (144) is sealed to the eleventh solenoid valve (V7). 11) One end is sealed and connected, and the other end of the eleventh solenoid valve (V11) is sealed and connected to one end of the second electromagnetic proportional regulating valve (VT2). One end of the tenth solenoid valve (V10) is sealed and connected between the ninth solenoid valve (V9) and the second pipeline filter (142). The other end of the tenth solenoid valve (V10) is sealed and connected between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). The first adsorption tower (143) and the second adsorption tower (144) are backups for each other. When one of the adsorption towers is saturated, the other adsorption tower is started to adsorb. The saturated adsorption tower is desorbed.

[0056] The distillation and purification apparatus (15) includes: a third compressor (K3), a second heat exchanger (151), a first manual valve (ST1), a distillation column (152), a refrigerator (153), a twelfth solenoid valve (V12), a thirteenth solenoid valve (V13), a third temporary storage tank (154), a fifth pressure sensor (P5), a third electromagnetic proportional regulating valve (VT3), and a second check valve (155). The input end of the third compressor (K3) is sealed to the output end of the second temporary storage tank (133), the output end of the third compressor (K3) is sealed to the top input end of the second heat exchanger (151), the bottom output end of the second heat exchanger (151) is sealed to one end of the first manual valve (ST1), and the other end of the first manual valve (ST1) is sealed to the bottom of the distillation column (152). The bottom of the distillation column (152) is sealed to the first manual valve (ST1). The top input end of the three temporary storage tanks (154) is sealed. The top of the distillation column (152) is sealed to one end of the third electromagnetic proportional control valve (VT3). The other end of the third electromagnetic proportional control valve (VT3) is sealed to the input end of the second one-way valve (155). The output end of the second one-way valve (155) is sealed between the second electromagnetic valve (V2) and the first electromagnetic proportional control valve (VT1). The input end of the refrigerator (153) is sealed to the distillation column (152) and the second heat exchanger (151) respectively. The output end of the refrigerator (153) is sealed to one end of the twelfth electromagnetic valve (V12) and the thirteenth electromagnetic valve (V13) respectively. The other end of the twelfth electromagnetic valve (V12) is sealed to the second heat exchanger (151). The other end of the thirteenth electromagnetic valve (V13) is sealed to the distillation column (152).

[0057] The filling pipeline (16) includes: a second manual valve (ST2), a fourth compressor (K4), a fourteenth solenoid valve (V14), a fifteenth solenoid valve (V15), a third check valve (161), and a sixth pressure sensor (P6); the bottom output end of the third temporary storage tank (154) is sealed to one end of the second manual valve (ST2), the other end of the second manual valve (ST2) is sealed to one end of the fifteenth solenoid valve (V15), and the other end of the fifteenth solenoid valve (V15) is connected to the fourth compressor (K4). The input end of the fourth compressor (K4) is sealed and connected to the input end of the third check valve (161). The output end of the third check valve (161) is sealed and connected to the filling port. One end of the fourteenth solenoid valve (V14) is sealed and connected between the second temporary storage tank (133) and the third compressor (K3). The other end of the fourteenth solenoid valve (V14) is sealed and connected between the third check valve (161) and the filling port. The sixth pressure sensor (P6) is sealed and installed between the third check valve (161) and the filling port.

[0058] Example 2

[0059] like Figure 3 As shown, the system's workflow is as follows:

[0060] 1. Filtration and purification of mixed gases

[0061] Open the first solenoid valve (V1), and the mixed gas passes through the first stage filtration and adsorption device (111), the second stage filtration and adsorption device (112), and the third stage filtration and adsorption device (113) in sequence for filtration and purification. The filtered and purified mixed gas then passes through the pressure reducing valve (JY) and the second solenoid valve (V2) in sequence into the preheating and stabilizing pipeline (12).

[0062] 2. Heating and pressurizing of mixed gases

[0063] Open the first electromagnetic proportional regulating valve (VT1), start the first compressor (K1), the first heat exchanger (122), and the gas heater (125) to heat and pressurize the filtered and purified mixed gas, so that the temperature and pressure of the mixed gas in the first temporary storage tank (124) are maintained at 40℃~55℃ and 0.7MPa~1.0MPa, at which time the separation efficiency of the mixed gas is the highest.

[0064] 3. Separation and enrichment of the mixed gas

[0065] Open the third solenoid valve (V3), and the mixed gas enters the organic membrane separation device module (13) for separation. The separated finished gas passes through the fifth solenoid valve (V5) and is stored in the second temporary storage tank (133). The separated tail gas passes through the fourth solenoid valve (V4) and enters the tail gas treatment device (14) for treatment. After separation and enrichment by the organic membrane separation device module (13), the C4F7N gas concentration in the C4F7N / CO2 mixed gas stored in the second temporary storage tank (133) is increased to about 90%.

[0066] 4. Exhaust gas treatment

[0067] Open the fourth solenoid valve (V4), the sixth solenoid valve (V6), and the eighth solenoid valve (V8), and start the second compressor (K2). The tail gas separated by the organic membrane separation device module (13) passes through the fourth solenoid valve (V4), the sixth solenoid valve (V6), and the first pipeline filter (141) into the first adsorption tower (143). The first adsorption tower (143) adsorbs C4F7N in the tail gas, and the remaining CO2 gas is discharged through the eighth solenoid valve (V8) and the second electromagnetic proportional regulating valve (VT2). When the first adsorption tower (143) is saturated, close the sixth solenoid valve (V6) and the eighth solenoid valve (V8). 8) Open the ninth solenoid valve (V9) and the eleventh solenoid valve (V11) so that the second adsorption tower (144) adsorbs C4F7N in the exhaust gas; at this time, open the seventh solenoid valve (V7), the first electromagnetic proportional regulating valve (VT1), and the first compressor (K1) to perform negative pressure desorption on the first adsorption tower (143), so that the first adsorption tower (143) can resume its adsorption function; the first adsorption tower (143) and the second adsorption tower (144) serve as backups for each other. When one of the adsorption towers is saturated, the other adsorption tower is turned on, so that the exhaust gas can be treated continuously, which improves the efficiency of exhaust gas treatment.

[0068] 5. Low-temperature distillation purification

[0069] The third compressor (K3) is turned on, and the first manual valve (ST1) is opened. The mixed gas in the second temporary storage tank (133) is input into the second heat exchanger (151) for preliminary cooling. The preliminarily cooled mixed gas then enters the distillation column (152) after passing through the first manual valve (ST1). The refrigerator (153) and the thirteenth solenoid valve (V13) are turned on. The refrigerator (153) cools down the distillation column (152). Due to the cooling and pressurization in the distillation column (152), the high-concentration mixed gas liquefies the C4F7N in the mixed gas. The CO2 in the combined gas remains in a gaseous state due to its low liquefaction temperature. The liquefied C4F7N is collected in the third temporary storage tank (154) at the bottom of the distillation column (152). The unliquefied CO2 gas and a small amount of C4F7N gas are discharged through the top of the distillation column (152). The discharged gas is returned to the preheating and stabilizing pipeline (12) for circulation through the third electromagnetic proportional regulating valve (VT3) and the second one-way valve (155). After low-temperature distillation purification, the purity of the liquid C4F7N in the second temporary storage tank (133) can reach more than 99%.

[0070] 6. Filling

[0071] Open the second manual valve (ST2) and the fifteenth solenoid valve (V15), and start the fourth compressor (K4) to fill the cylinder with liquid C4F7N from the third temporary storage tank (154). After filling, close the second manual valve (ST2), and open the fourteenth solenoid valve (V14) and the third compressor (K3) to recover the remaining liquid C4F7N in the pipeline.

[0072] Example 3

[0073] The preparation method of the metal-organic framework (MOFs) is as follows:

[0074] (1) Prepare a 0.32M sodium benzoate aqueous solution; prepare a 0.16M copper sulfate aqueous solution; prepare a 0.16M 1,10-o-phenanthroline methanol solution;

[0075] (2) Take 10 mL of the above sodium benzoate aqueous solution, 10 mL of the above 1,10-o-phenanthroline methanol solution and 10 mL of the above copper sulfate aqueous solution, put them into a polytetrafluoroethylene tube, and then add 10 mL of methanol and mix well; seal the polytetrafluoroethylene tube in a stainless steel reactor, react at 160℃ for 48 h, and then cool to room temperature to obtain blue transparent block crystals. Wash the blue transparent block crystals with water and methanol three times each, and dry them in air for 1 h to obtain the target product metal-organic framework material with a yield of 37.6%.

[0076] The metal-organic framework (MOF) materials prepared in Example 3 were tested. Single-crystal X-ray diffraction data were collected using a Rigaku Supernova CCD single-crystal X-ray diffractometer (Japan), at a test temperature of 298(2) K and a test wavelength of 0.71073 Å. The raw data were empirically corrected for absorption using the spherical harmonic function in SCALE3 ABSPACk software. The initial structure of the MOF materials was directly resolved using SHELXTL software and refined using the F2-based full matrix least squares method. In the final round of refinement, non-hydrogen atoms underwent anisotropic refinement. Hydrogen atoms on the ligands were added using the theoretical hydrogenation method. Specific test and analysis conditions and crystal data are shown in the table below:

[0077]

[0078] Typical bond length data for metal-organic framework crystals are as follows:

[0079]

[0080] Typical bond angle data for metal-organic framework crystals are shown in the table below:

[0081]

[0082] Figure 4 The molecular structural formula of the metal-organic framework material prepared in the embodiments of the present invention is shown below; Figure 4 It is known that the organic ligand forms a metal-organic framework with copper ions as the coordination center. In this metal-organic framework material, the copper ions coordinate with two surrounding oxygen atoms and two nitrogen atoms in a 4-coordinate mode. The two oxygen atoms come from two sodium benzoates, and the two nitrogen atoms come from one 1,10-o-phenanthroline.

[0083] Figure 5 This is a unit cell packing diagram of the metal-organic framework material prepared according to an embodiment of the present invention; by Figure 5 It is known that the metal-organic framework molecules prepared in this invention are stacked to form a three-dimensional framework structure.

[0084] Example 4

[0085] The method for preparing the metal-organic framework (MOF) materials includes the following steps:

[0086] (1) Prepare a 0.16 M sodium benzoate aqueous solution; prepare a 0.16 M copper sulfate aqueous solution; prepare a 0.16 M 1,10-o-phenanthroline methanol solution;

[0087] (2) Take 10 mL of the above sodium benzoate aqueous solution, 10 mL of the above 1,10-o-phenanthroline methanol solution and 10 mL of the above copper sulfate aqueous solution, put them into a polytetrafluoroethylene tube, and then add 10 mL of methanol and mix well; seal the polytetrafluoroethylene tube in a stainless steel reactor, react at 140℃ for 48 h, and then cool to room temperature to obtain blue transparent block crystals. Wash the blue transparent block crystals with water and methanol three times each, and dry them in air for 1 h to obtain the target product metal-organic framework material with a yield of 34.3%.

[0088] Example 5

[0089] The method for preparing the metal-organic framework (MOF) materials includes the following steps:

[0090] (1) Prepare a sodium benzoate aqueous solution with a concentration of 0.48 M; prepare a copper sulfate aqueous solution with a concentration of 0.32 M; prepare a 1,10-o-phenanthroline methanol solution with a concentration of 0.16 M;

[0091] (2) Take 10 mL of the above sodium benzoate aqueous solution, 10 mL of the above 1,10-o-phenanthroline methanol solution and 10 mL of the above copper sulfate aqueous solution, put them into a polytetrafluoroethylene tube, and then add 10 mL of methanol and mix well; seal the polytetrafluoroethylene tube in a stainless steel reactor, react at 180℃ for 24 h, and then cool to room temperature to obtain blue transparent block crystals. Wash the blue transparent block crystals with water and methanol three times each, and dry them in air for 1 h to obtain the target product metal-organic framework material with a yield of 36.5%.

[0092] Example 6

[0093] The method for preparing the metal-organic framework (MOF) materials includes the following steps:

[0094] (1) Prepare a 0.32 M sodium benzoate aqueous solution; prepare a 0.48 M copper sulfate aqueous solution; prepare a 0.16 M 1,10-o-phenanthroline methanol solution;

[0095] (2) Take 10 mL of the above sodium benzoate aqueous solution, 10 mL of the above 1,10-o-phenanthroline methanol solution and 10 mL of the above copper sulfate aqueous solution, put them into a polytetrafluoroethylene tube, and then add 10 mL of methanol and mix well; seal this polytetrafluoroethylene tube in a stainless steel reactor, react at 180℃ for 48 h, and then cool to room temperature to obtain blue transparent block crystals. Wash the blue transparent block crystals with water and methanol three times each, and dry them in air for 1 h to obtain the target product metal-organic framework material with a yield of 39.1%.

[0096] Comparative Example 1

[0097] The difference from Example 3 is that copper sulfate was replaced with other metal salts (such as zinc nitrate, nickel nitrate, cobalt nitrate, cobalt acetate, magnesium sulfate, or calcium nitrate), and all of them were amorphous powders, and no crystal samples with single crystal structure were obtained.

[0098] The metal-organic framework material prepared in Example 3 of this invention and Comparative Example 1 (an amorphous powder prepared using calcium nitrate as a metal salt) were filled into an adsorption vessel. The adsorption vessel was a cylinder with an inner diameter of 20 cm and a length of 40 cm. Pressure and flow control instruments were installed at the inlet, and the outlet was connected to a gas chromatograph. C4F7N containing a certain amount of decomposition product impurities was passed through the adsorption vessel, and the gas flow rate was controlled. The content of impurities such as CNCN before and after adsorption was detected. The results are shown in Table 1.

[0099] Table 1. Adsorption test results of adsorption materials for impurity gases in C4F7N

[0100]

[0101] As shown in the table above, the metal-organic framework materials synthesized in this invention all have a certain adsorption capacity for C4F7N decomposition products, among which CNCN has the best adsorption effect.

[0102] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A C4F7N / CO2 mixed gas purification system, characterized in that, include: The system comprises a filtration and adsorption device (11), a preheating and pressure stabilizing pipeline (12), an organic membrane separation device module (13), a tail gas treatment device (14), a distillation and purification device (15), and a filling pipeline (16). The output end of the filtration and adsorption device (11) is sealed to the input end of the preheating and pressure stabilizing pipeline (12), the output end of the preheating and pressure stabilizing pipeline (12) is sealed to the input end of the organic membrane separation device module (13), the first output end of the organic membrane separation device module (13) is sealed to the input end of the distillation and purification device (15), and the second output end of the organic membrane separation device module (13) is sealed to the input end of the tail gas treatment device (14). The first output end of the exhaust gas treatment device (14) is sealed between the filter adsorption device (11) and the preheating and stabilizing pipeline (12). The second output end of the exhaust gas treatment device (14) serves as the system's vent. The first output end of the distillation and purification device (15) is sealed between the input end of the filling pipeline (16). The second output end of the distillation and purification device (15) is sealed between the filter adsorption device (11) and the preheating and stabilizing pipeline (12). The first output end of the filling pipeline (16) is sealed between the organic membrane separation device module (13) and the distillation and purification device (15). The second output end of the filling pipeline (16) serves as the system's output end. The filter adsorption device (11) includes: a first pressure sensor (P1), a first solenoid valve (V1), a first-stage filter adsorption device (111), a second-stage filter adsorption device (112), a third-stage filter adsorption device (113), a pressure reducing valve (JY), and a second solenoid valve (V2); one end of the first solenoid valve (V1) is sealed to the air inlet, and the other end of the first solenoid valve (V1) is sealed to the bottom input end of the first-stage filter adsorption device (111). The top output end of the device is sealed to the bottom input end of the second-stage filtration and adsorption device (112), the top output end of the second-stage filtration and adsorption device (112) is sealed to the bottom input end of the third-stage filtration and adsorption device (113), the top output end of the third-stage filtration and adsorption device (113) is sealed to one end of the pressure reducing valve (JY), the other end of the pressure reducing valve (JY) is sealed to one end of the second solenoid valve (V2), and the first pressure sensor (P1) is sealed between the air inlet and the first solenoid valve (V1). The first-stage filtration and adsorption device (111) is filled with porous metal filter material to remove dust from the mixed gas; the second-stage filtration and adsorption device (112) is filled with 5A molecular sieve and silica gel adsorbent to remove moisture from the mixed gas; and the third-stage filtration and adsorption device (113) is filled with metal-organic framework material to selectively adsorb CF3CN, CNCN, and C2F5CN impurity components in the mixed gas.

2. The C4F7N / CO2 mixed gas purification system according to claim 1, characterized in that, The preheating and stabilizing pipeline (12) includes: a first electromagnetic proportional regulating valve (VT1), a first compressor (K1), a first check valve (121), a first heat exchanger (122), a pressure control device (123), a first temporary storage tank (124), a second pressure sensor (P2), a first temperature sensor (T1), and a gas heater (125); one end of the first electromagnetic proportional regulating valve (VT1) is sealed to the other end of the second electromagnetic valve (V2), the other end of the first electromagnetic proportional regulating valve (VT1) is sealed to the input end of the first compressor (K1), and the output end of the first compressor (K1) is sealed to the input end of the first compressor (K1). The input end of the first one-way valve (121) is sealed and connected, the output end of the first one-way valve (121) is sealed and connected to the input end of the first heat exchanger (122), the output end of the first heat exchanger (122) is sealed and connected to the input end of the first temporary storage tank (124), the output end of the first temporary storage tank (124) is sealed and connected to the input end of the gas heater (125), the pressure control device (123) is sealed and installed between the first heat exchanger (122) and the first temporary storage tank (124), and the second pressure sensor (P2) and the first temperature sensor (T1) are both sealed and installed on the top of the first temporary storage tank (124).

3. The C4F7N / CO2 mixed gas purification system according to claim 2, characterized in that, The organic membrane separation device module (13) includes: a third solenoid valve (V3), an organic membrane separation device (131), a gas purity sampling device (132), a fourth solenoid valve (V4), a fifth solenoid valve (V5), a second temporary storage tank (133), and a third pressure sensor (P3); one end of the third solenoid valve (V3) is sealed to the output end of the gas heater (125), and the other end of the third solenoid valve (V3) is sealed to the top input end of the organic membrane separation device (131); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4). The second output end is used to discharge the tail gas separated by the organic membrane separation device (131). The second output end of the organic membrane separation device (131) is sealed to one end of the fifth solenoid valve (V5). The second output end of the organic membrane separation device (131) is used to output the finished gas separated by the organic membrane separation device (131). The other end of the fifth solenoid valve (V5) is sealed to the top input end of the second temporary storage tank (133). The gas purity sampling device (132) is sealed between the second output end of the organic membrane separation device (131) and the fifth solenoid valve (V5). The third pressure sensor (P3) is sealed to the top of the second temporary storage tank (133).

4. The C4F7N / CO2 mixed gas purification system according to claim 3, characterized in that, The exhaust gas treatment device (14) includes: a second compressor (K2), a sixth solenoid valve (V6), a seventh solenoid valve (V7), an eighth solenoid valve (V8), a ninth solenoid valve (V9), a tenth solenoid valve (V10), an eleventh solenoid valve (V11), a first pipeline filter (141), a second pipeline filter (142), a first adsorption tower (143), a second adsorption tower (144), a second electromagnetic proportional regulating valve (VT2), an exhaust sampling device (145), and a fourth pressure sensor (P4); the input end of the second compressor (K2) is sealed to the other end of the fourth solenoid valve (V4). Next, one end of the sixth solenoid valve (V6) is sealed to the output end of the second compressor (K2), and the other end of the sixth solenoid valve (V6) is sealed to the input end of the first pipeline filter (141). The output end of the first pipeline filter (141) is sealed to the input end of the first adsorption tower (143), and the output end of the first adsorption tower (143) is sealed to one end of the eighth solenoid valve (V8). The other end of the eighth solenoid valve (V8) is sealed to one end of the second electromagnetic proportional regulating valve (VT2), and the other end of the second electromagnetic proportional regulating valve (VT2) is sealed to the vent. The seventh solenoid valve... One end of the seventh solenoid valve (V7) is sealed between the sixth solenoid valve (V6) and the first pipeline filter (141). The other end of the seventh solenoid valve (V7) is sealed between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). One end of the ninth solenoid valve (V9) is sealed to the output end of the second compressor (K2), and the other end of the ninth solenoid valve (V9) is sealed to the input end of the second pipeline filter (142). The output end of the second pipeline filter (142) is sealed to the input end of the second adsorption tower (144), and the output end of the second adsorption tower (144) is sealed to the eleventh solenoid valve (V7). 11) One end is sealed and connected, and the other end of the eleventh solenoid valve (V11) is sealed and connected to one end of the second electromagnetic proportional regulating valve (VT2). One end of the tenth solenoid valve (V10) is sealed and connected between the ninth solenoid valve (V9) and the second pipeline filter (142). The other end of the tenth solenoid valve (V10) is sealed and connected between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). The first adsorption tower (143) and the second adsorption tower (144) are backups for each other. When one of the adsorption towers is saturated, the other adsorption tower is started to adsorb. The saturated adsorption tower is desorbed.

5. The C4F7N / CO2 mixed gas purification system according to claim 4, characterized in that, The distillation and purification apparatus (15) includes: a third compressor (K3), a second heat exchanger (151), a first manual valve (ST1), a distillation column (152), a refrigerator (153), a twelfth solenoid valve (V12), a thirteenth solenoid valve (V13), a third temporary storage tank (154), a fifth pressure sensor (P5), a third electromagnetic proportional regulating valve (VT3), and a second check valve (155). The input end of the third compressor (K3) is sealed to the output end of the second temporary storage tank (133), the output end of the third compressor (K3) is sealed to the top input end of the second heat exchanger (151), the bottom output end of the second heat exchanger (151) is sealed to one end of the first manual valve (ST1), and the other end of the first manual valve (ST1) is sealed to the bottom of the distillation column (152). The bottom of the distillation column (152) is sealed to the first manual valve (ST1). The top input end of the three temporary storage tanks (154) is sealed. The top of the distillation column (152) is sealed to one end of the third electromagnetic proportional control valve (VT3). The other end of the third electromagnetic proportional control valve (VT3) is sealed to the input end of the second one-way valve (155). The output end of the second one-way valve (155) is sealed between the second electromagnetic valve (V2) and the first electromagnetic proportional control valve (VT1). The input end of the refrigerator (153) is sealed to the distillation column (152) and the second heat exchanger (151) respectively. The output end of the refrigerator (153) is sealed to one end of the twelfth electromagnetic valve (V12) and the thirteenth electromagnetic valve (V13) respectively. The other end of the twelfth electromagnetic valve (V12) is sealed to the second heat exchanger (151). The other end of the thirteenth electromagnetic valve (V13) is sealed to the distillation column (152).

6. The C4F7N / CO2 mixed gas purification system according to claim 5, characterized in that, The filling pipeline (16) includes: a second manual valve (ST2), a fourth compressor (K4), a fourteenth solenoid valve (V14), a fifteenth solenoid valve (V15), a third check valve (161), and a sixth pressure sensor (P6); the bottom output end of the third temporary storage tank (154) is sealed to one end of the second manual valve (ST2), the other end of the second manual valve (ST2) is sealed to one end of the fifteenth solenoid valve (V15), and the other end of the fifteenth solenoid valve (V15) is connected to the fourth compressor (K4). The input end of the fourth compressor (K4) is sealed and connected to the input end of the third check valve (161). The output end of the third check valve (161) is sealed and connected to the filling port. One end of the fourteenth solenoid valve (V14) is sealed and connected between the second temporary storage tank (133) and the third compressor (K3). The other end of the fourteenth solenoid valve (V14) is sealed and connected between the third check valve (161) and the filling port. The sixth pressure sensor (P6) is sealed and installed between the third check valve (161) and the filling port.

7. The C4F7N / CO2 mixed gas purification system according to claim 6, characterized in that, The metal-organic framework material is prepared by reacting 1,10-phenanthroline with sodium benzoate and copper sulfate; its molecular formula is C0. 26 H 18 Cu1N2O4 belongs to the orthorhombic crystal system, space group Fdd2, with the following cell parameters: a=41.156(3)Å, b=5.6892(4)Å, c=18.3043(16)Å, α=90°, β=108.502(2)°, γ=90°, and a cell volume of 4285.8(6)Å. 3 .

8. The C4F7N / CO2 mixed gas purification system according to claim 7, characterized in that, The preparation method of the metal-organic framework material includes the following steps: dissolving sodium benzoate, copper sulfate, and 1,10-o-phenanthroline in a mixed solution of water and methanol to obtain a reaction solution; placing the reaction solution in a hydrothermal reactor for reaction, and cooling to room temperature to obtain the metal-organic framework material; the molar ratio of sodium benzoate, copper sulfate, and 1,10-o-phenanthroline is 1-3:1-3:1; the volume ratio of water to methanol in the mixed solution is 1:1; the concentration of 1,10-o-phenanthroline in the reaction solution is 0.04 mmol / ml; the reaction temperature in the hydrothermal reactor is 140-180℃, and the reaction time is 24-48 h.

9. A purification method applied to the C4F7N / CO2 mixed gas purification system according to any one of claims 1 to 8, characterized in that, Includes the following steps: SS1. The input C4F7N / CO2 mixed gas is filtered and purified using a filter adsorption device (11); SS2. Turn on the preheating and pressure stabilizing pipeline (12) to heat and pressurize the C4F7N / CO2 mixed gas; SS3. The organic membrane separation device module (13) is used to separate C4F7N and CO2 in the C4F7N / CO2 mixed gas and enrich the C4F7N gas. SS4. The CO2 and C4F7N mixed exhaust gas separated by the organic membrane separation device module (13) is input into the exhaust gas treatment device (14) for treatment; SS5. Start the distillation and purification unit (15) to distill and purify the enriched C4F7N / CO2 mixed gas; SS6. The liquid C4F7N purified by distillation in the distillation purification device (15) is filled using the filling pipeline (16).

10. The purification treatment method according to claim 9, characterized in that, The filter adsorption device (11) includes: a first solenoid valve (V1), a first-stage filter adsorption device (111), a second-stage filter adsorption device (112), a third-stage filter adsorption device (113), a pressure reducing valve (JY), and a second solenoid valve (V2); one end of the first solenoid valve (V1) is sealed to the air inlet, and the other end of the first solenoid valve (V1) is sealed to the bottom input end of the first-stage filter adsorption device (111), and the top output of the first-stage filter adsorption device (111) is... The end of the first stage filter adsorption device (112) is sealed to the bottom input end of the second stage filter adsorption device (112), the top output end of the second stage filter adsorption device (112) is sealed to the bottom input end of the third stage filter adsorption device (113), the top output end of the third stage filter adsorption device (113) is sealed to one end of the pressure reducing valve (JY), the other end of the pressure reducing valve (JY) is sealed to one end of the second solenoid valve (V2), and the other end of the second solenoid valve (V2) is sealed to the preheating pressure stabilizing pipeline (12). The method of using a filter adsorption device (11) to filter and purify the input C4F7N / CO2 mixed gas in step SS1 is as follows: Open the first solenoid valve (V1), and the input C4F7N / CO2 mixed gas passes through the first stage filter adsorption device (111), the second stage filter adsorption device (112), and the third stage filter adsorption device (113) in sequence for filtration and purification. The filtered and purified mixed gas then passes through the pressure reducing valve (JY) and the second solenoid valve (V2) in sequence into the preheating and stabilizing pipeline (12).

11. The purification treatment method according to claim 10, characterized in that, The preheating and stabilizing pipeline (12) includes: a first electromagnetic proportional regulating valve (VT1), a first compressor (K1), a first check valve (121), a first heat exchanger (122), a pressure control device (123), a first temporary storage tank (124), a second pressure sensor (P2), a first temperature sensor (T1), and a gas heater (125); one end of the first electromagnetic proportional regulating valve (VT1) is sealed to the other end of the second electromagnetic valve (V2), the other end of the first electromagnetic proportional regulating valve (VT1) is sealed to the input end of the first compressor (K1), and the output end of the first compressor (K1) is sealed to the input end of the first compressor (K1). The input end of the first one-way valve (121) is sealed and connected, the output end of the first one-way valve (121) is sealed and connected to the input end of the first heat exchanger (122), the output end of the first heat exchanger (122) is sealed and connected to the input end of the first temporary storage tank (124), the output end of the first temporary storage tank (124) is sealed and connected to the input end of the gas heater (125), the pressure control device (123) is sealed and installed between the first heat exchanger (122) and the first temporary storage tank (124), and the second pressure sensor (P2) and the first temperature sensor (T1) are both sealed and installed on the top of the first temporary storage tank (124); The method for heating and pressurizing the C4F7N / CO2 mixed gas by opening the preheating and pressure stabilizing pipeline (12) in step SS2 is as follows: open the first electromagnetic proportional regulating valve (VT1), turn on the first compressor (K1), the first heat exchanger (122), and the gas heater (125) to heat and pressurize the filtered and purified mixed gas, so that the temperature and pressure of the mixed gas in the first temporary storage tank (124) are maintained at 40℃~55℃ and 0.7MPa~1.0MPa.

12. The purification treatment method according to claim 11, characterized in that, The organic membrane separation device module (13) includes: a third solenoid valve (V3), an organic membrane separation device (131), a gas purity sampling device (132), a fourth solenoid valve (V4), a fifth solenoid valve (V5), a second temporary storage tank (133), and a third pressure sensor (P3); one end of the third solenoid valve (V3) is sealed to the output end of the gas heater (125), and the other end of the third solenoid valve (V3) is sealed to the top input end of the organic membrane separation device (131); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4); the first output end of the organic membrane separation device (131) is sealed to one end of the fourth solenoid valve (V4). The second output end is used to discharge the tail gas separated by the organic membrane separation device (131). The second output end of the organic membrane separation device (131) is sealed to one end of the fifth solenoid valve (V5). The second output end of the organic membrane separation device (131) is used to output the finished gas separated by the organic membrane separation device (131). The other end of the fifth solenoid valve (V5) is sealed to the top input end of the second temporary storage tank (133). The gas purity sampling device (132) is sealed between the second output end of the organic membrane separation device (131) and the fifth solenoid valve (V5). The third pressure sensor (P3) is sealed to the top of the second temporary storage tank (133). The method described in step SS3 for separating C4F7N and CO2 in the C4F7N / CO2 mixed gas using an organic membrane separation device module (13) and enriching C4F7N gas is as follows: the third solenoid valve (V3) is opened, the mixed gas enters the organic membrane separation device module (13) for separation, the separated finished gas passes through the fifth solenoid valve (V5) and is stored in the second temporary storage tank (133), and the separated tail gas passes through the fourth solenoid valve (V4) and enters the tail gas treatment device (14) for treatment.

13. The purification treatment method according to claim 12, characterized in that, The exhaust gas treatment device (14) includes: a second compressor (K2), a sixth solenoid valve (V6), a seventh solenoid valve (V7), an eighth solenoid valve (V8), a ninth solenoid valve (V9), a tenth solenoid valve (V10), an eleventh solenoid valve (V11), a first pipeline filter (141), a second pipeline filter (142), a first adsorption tower (143), a second adsorption tower (144), a second electromagnetic proportional regulating valve (VT2), an exhaust sampling device (145), and a fourth pressure sensor (P4); the input end of the second compressor (K2) The other end of the sixth solenoid valve (V6) is sealed to the other end of the fourth solenoid valve (V4). One end of the sixth solenoid valve (V6) is sealed to the output end of the second compressor (K2), and the other end of the sixth solenoid valve (V6) is sealed to the input end of the first pipeline filter (141). The output end of the first pipeline filter (141) is sealed to the input end of the first adsorption tower (143), and the output end of the first adsorption tower (143) is sealed to one end of the eighth solenoid valve (V8). The other end of the eighth solenoid valve (V8) is sealed to one end of the second electromagnetic proportional regulating valve (VT2). The other end of the second electromagnetic proportional control valve (VT2) is sealed to the vent port. One end of the seventh electromagnetic valve (V7) is sealed between the sixth electromagnetic valve (V6) and the first pipeline filter (141). The other end of the seventh electromagnetic valve (V7) is sealed between the second electromagnetic valve (V2) and the first electromagnetic proportional control valve (VT1). One end of the ninth electromagnetic valve (V9) is sealed to the output end of the second compressor (K2). The other end of the ninth electromagnetic valve (V9) is sealed to the input end of the second pipeline filter (142). The output end of (142) is sealed to the input end of the second adsorption tower (144), the output end of the second adsorption tower (144) is sealed to one end of the eleventh solenoid valve (V11), the other end of the eleventh solenoid valve (V11) is sealed to one end of the second electromagnetic proportional regulating valve (VT2), one end of the tenth solenoid valve (V10) is sealed between the ninth solenoid valve (V9) and the second pipeline filter (142), and the other end of the tenth solenoid valve (V10) is sealed between the second solenoid valve (V2) and the first electromagnetic proportional regulating valve (VT1). The specific method for inputting the mixed CO2 and C4F7N tail gas separated by the organic membrane separation device module (13) into the tail gas treatment device (14) for treatment in step SS4 is as follows: Open the fourth solenoid valve (V4), the sixth solenoid valve (V6), and the eighth solenoid valve (V8), and start the second compressor (K2). The tail gas separated by the organic membrane separation device module (13) passes through the fourth solenoid valve (V4), the sixth solenoid valve (V6), and the first pipeline filter (141) into the first adsorption tower (143). The first adsorption tower (143) adsorbs the C4F7N in the tail gas, and the remaining CO2 and C4F7N are then adsorbed. CO2 gas is discharged through the eighth solenoid valve (V8) and the second electromagnetic proportional regulating valve (VT2). When the first adsorption tower (143) is saturated, the sixth solenoid valve (V6) and the eighth solenoid valve (V8) are closed, and the ninth solenoid valve (V9) and the eleventh solenoid valve (V11) are opened. The second adsorption tower (144) adsorbs C4F7N in the tail gas. At this time, the seventh solenoid valve (V7), the first electromagnetic proportional regulating valve (VT1), and the first compressor (K1) are opened to perform negative pressure desorption on the first adsorption tower (143), so that the first adsorption tower (143) can resume its adsorption function.

14. The purification treatment method according to claim 13, characterized in that, The distillation and purification apparatus (15) includes: a third compressor (K3), a second heat exchanger (151), a first manual valve (ST1), a distillation column (152), a refrigerator (153), a twelfth solenoid valve (V12), a thirteenth solenoid valve (V13), a third temporary storage tank (154), a fifth pressure sensor (P5), a third electromagnetic proportional regulating valve (VT3), and a second check valve (155). The input end of the third compressor (K3) is sealed to the output end of the second temporary storage tank (133), the output end of the third compressor (K3) is sealed to the top input end of the second heat exchanger (151), the bottom output end of the second heat exchanger (151) is sealed to one end of the first manual valve (ST1), and the other end of the first manual valve (ST1) is sealed to the bottom of the distillation column (152). The bottom of the distillation column (152) is sealed to the first manual valve (ST1). The top input end of the three temporary storage tanks (154) is sealed and connected. The top of the distillation column (152) is sealed and connected to one end of the third electromagnetic proportional control valve (VT3). The other end of the third electromagnetic proportional control valve (VT3) is sealed and connected to the input end of the second one-way valve (155). The output end of the second one-way valve (155) is sealed and connected between the second electromagnetic valve (V2) and the first electromagnetic proportional control valve (VT1). The input end of the refrigerator (153) is sealed and connected to the distillation column (152) and the second heat exchanger (151) respectively. The output end of the refrigerator (153) is sealed and connected to one end of the twelfth electromagnetic valve (V12) and the thirteenth electromagnetic valve (V13) respectively. The other end of the twelfth electromagnetic valve (V12) is sealed and connected to the second heat exchanger (151). The other end of the thirteenth electromagnetic valve (V13) is sealed and connected to the distillation column (152). The specific method for purifying the enriched C4F7N / CO2 mixed gas by starting the distillation purification device (15) as described in step SS5 is as follows: The third compressor (K3) is turned on, and the first manual valve (ST1) is opened. The mixed gas in the second temporary storage tank (133) is input into the second heat exchanger (151) for preliminary cooling. The preliminarily cooled mixed gas then enters the distillation column (152) after passing through the first manual valve (ST1). The refrigerator (153) and the thirteenth solenoid valve (V13) are turned on. The refrigerator (153) cools the distillation column (152). The high concentration of the mixed gas in the distillation column (152) is due to... The C4F7N in the mixed gas is liquefied by cooling and pressurizing. The CO2 in the mixed gas is still in a gaseous state due to the low liquefaction temperature. The liquefied C4F7N is collected in the third temporary storage tank (154) at the bottom of the distillation column (152). The unliquefied CO2 gas and a small amount of C4F7N gas are discharged through the top of the distillation column (152). The discharged gas is returned to the preheating and pressure stabilizing pipeline (12) for circulation through the third electromagnetic proportional regulating valve (VT3) and the second one-way valve (155).

15. The purification treatment method according to claim 14, characterized in that, The filling pipeline (16) includes: a second manual valve (ST2), a fourth compressor (K4), a fourteenth solenoid valve (V14), a fifteenth solenoid valve (V15), a third check valve (161), and a sixth pressure sensor (P6); the bottom output end of the third temporary storage tank (154) is sealed to one end of the second manual valve (ST2), the other end of the second manual valve (ST2) is sealed to one end of the fifteenth solenoid valve (V15), and the other end of the fifteenth solenoid valve (V15) is connected to the fourth compressor (K4). The input end of the fourth compressor (K4) is sealed and connected to the input end of the third check valve (161). The output end of the third check valve (161) is sealed and connected to the filling port. One end of the fourteenth solenoid valve (V14) is sealed and connected between the second temporary storage tank (133) and the third compressor (K3). The other end of the fourteenth solenoid valve (V14) is sealed and connected between the third check valve (161) and the filling port. The sixth pressure sensor (P6) is sealed and installed between the third check valve (161) and the filling port. The method described in step SS6 for filling the liquid C4F7N purified by distillation in the distillation purification device (15) using the filling pipeline (16) is as follows: open the second manual valve (ST2) and the fifteenth solenoid valve (V15), turn on the fourth compressor (K4) to fill the liquid C4F7N in the third temporary storage tank (154) into the steel cylinder. After filling, close the second manual valve (ST2), turn on the fourteenth solenoid valve (V14) and the third compressor (K3) to recover the remaining liquid C4F7N in the pipeline.

Images