System for recovering dichloromethane from waste gas

Abstract

The utility model discloses a system for recovering dichloromethane from waste gas, which is characterized in that a retentate side outlet of a first membrane separation device of the system is connected with an inlet of a second membrane separation device, and a permeation side outlet of the first membrane separation device and a permeation side outlet of the second membrane separation device are connected with an inlet of a condensing device; when the condensing device is a normal-pressure condensing device, a tail gas outlet of the condensing device is connected with an inlet of the first membrane separation device, and when the condensing device is a compression condensing device, the tail gas outlet of the condensing device is connected with an inlet of the second membrane separation device. The system and the method are efficient, environment-friendly, economical and feasible, and can be used for recovering high-concentration dichloromethane from the waste gas and ensuring that the treated gas reaches the emission standard.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of environmental protection, concretely relates to a system for recovering dichloromethane from waste gas. BACKGROUND

[0002] Dichloromethane (DCM) has high polarity, low flammability and good solubility, and is often used as a solvent, an extractant and a reaction medium, and is widely used in pharmaceuticals, new energy lithium batteries, organic synthesis, semiconductors and other fields. However, dichloromethane has a low boiling point and is easily volatile to the surrounding environment, and too much inhalation can cause harm to the human body, and also decomposes under the action of light to produce highly toxic phosgene. Therefore, efficient treatment of dichloromethane waste gas has become one of the environmental problems to be solved.

[0003] Common dichloromethane treatment technologies mainly include combustion method, biological degradation method, condensation method, adsorption method, absorption method and membrane separation method. In practical application, two or more combined technologies are sometimes used for treatment, such as compression condensation-adsorption method. Combustion method, absorption method, condensation method and adsorption method are currently the most mature and widely used dichloromethane treatment technologies worldwide. Traditional membrane separation technology is mainly used for the treatment of low-concentration dichloromethane waste gas. The basic principle of membrane separation technology is to separate the target component from other components by using the different diffusion speeds of gas components through the membrane. Membrane separation technology is best used for treating low-concentration dichloromethane waste gas (concentration less than 8%), and can efficiently separate dichloromethane from waste gas.

[0004] However, the current membrane separation technology faces the following problems, which limits its application in high-concentration dichloromethane waste gas: (1) although membrane separation can efficiently separate dichloromethane from low-concentration dichloromethane waste gas, when the concentration of waste gas increases, the membrane surface will form a relatively dense layer of dichloromethane molecules due to concentration polarization phenomenon, and the performance of the membrane will be greatly reduced. (2) During the treatment of high-concentration dichloromethane waste gas, the interaction between dichloromethane and other components may cause contamination or failure of the membrane material. Some traditional membrane materials may have reduced permeability, and even corrosion and degradation under the erosion of high-concentration dichloromethane waste gas, affecting their separation effect and service life.

[0005] Therefore, there is an urgent need for a new method to overcome the shortcomings of existing membrane separation technology in treating high-concentration dichloromethane waste gas, improve recovery efficiency, reduce energy consumption, and prolong the service life of the membrane. UTILITY MODEL CONTENT

[0006] In view of the above problems, the utility model provides a system for recovering dichloromethane from waste gas, which is efficient, environmentally friendly and economically feasible, and can be used for recovering medium and high concentration dichloromethane from waste gas, and ensuring that the treated gas meets the emission standard.

[0007] To achieve the above object, the utility model adopts the following technical scheme:

[0008] A system for recovering dichloromethane from waste gas, the retentate side outlet of the first membrane separation device is connected to the inlet of the second membrane separation device, the permeate side outlet of the first membrane separation device and the permeate side outlet of the second membrane separation device are connected to the inlet of the condensing device,

[0009] When the condensing device is a normal pressure condensing device, the tail gas outlet of the condensing device is connected to the inlet of the first membrane separation device,

[0010] When the condensing device is a compression condensing device, the tail gas outlet of the condensing device is connected to the inlet of the second membrane separation device. The design of the condenser takes into account the flexibility in different application scenarios, which can significantly improve the overall recovery rate of dichloromethane, reduce emissions, and ensure the continuity and stability of the entire recovery process.

[0011] The utility model realizes efficient concentration and liquefied recovery of dichloromethane by combining two-stage membrane separation and condensing technology, and ensures that the treated gas meets the emission standard.

[0012] Further, the inlet of the first membrane separation device is also provided with a fan. The waste gas as raw material enters the first membrane separation device after being pressurized by the fan. The pressurization process not only increases the pressure of the gas, but also helps to improve the flow characteristics of the gas on the membrane surface, thereby improving the membrane separation efficiency.

[0013] Further, the fan is an explosion-proof centrifugal fan or a vortex fan. To ensure safety in an environment where flammable gas may exist.

[0014] Further, the compressor of the compression condensing device is a liquid injection screw compressor. The working pressure range of the compressor is 0.4~0.8MPaG, and through the adjustment of the liquid injection system, the compression process of the gas can be effectively controlled, avoiding energy waste caused by excessive temperature or low efficiency. The compressor is used to increase the pressure of dichloromethane vapor and condense it, while providing power for the non-condensable gas entering the second membrane separation system.

[0015] Further, the membrane material of the first membrane separation device is a mixed matrix membrane or a perfluoropolymer membrane. The mixed matrix membrane includes at least one of polyoctylmethylsiloxane, polydimethylsiloxane or polyphenylmethylsiloxane. The perfluoropolymer membrane includes polyperfluoroalkylvinylether (CYTOP). A dichloromethane-resistant VOCs recovery organic membrane can also be used, which includes, in sequence, a base film layer, an intermediate layer and an active layer, the base film layer being polyvinylidene fluoride, the intermediate layer being polybenzimidazole dispersed with a hydrogen-bond organic framework material, and the active layer being cross-linked polydimethylsiloxane. The base film layer material is polyvinylidene fluoride, which has good mechanical strength and chemical stability; the intermediate layer is polybenzimidazole dispersed with a hydrogen-bond organic framework material, which enhances the selectivity and permeability of the membrane; and the active layer is cross-linked polydimethylsiloxane, which has high affinity for dichloromethane and can allow dichloromethane to preferentially permeate.

[0016] Preferably, the hydrogen-bond organic framework material is H IAM-JM, and the hydrogen-bond organic framework material is subjected to an activation treatment, and the H IAM-JM is prepared by the following method:

[0017] The 2,2-dithiodibenzoic acid and acetic acid are uniformly dispersed in a ratio of 0.05-0.1 g: 50-80 mL, and then reacted at 70-90°C under vacuum for 10-14 h to obtain the H IAM-JM.

[0018] Preferably, the dichloromethane-resistant VOCs recovery organic membrane is prepared by the following method:

[0019] The first coating solution is coated on the base film, and after pre-drying, the second coating solution is coated thereon, and then cross-linked at high temperature to obtain the dichloromethane-resistant VOCs recovery organic membrane.

[0020] The first coating solution is prepared by the following method: the hydrogen-bond organic framework material is ultrasonically oscillated in n-heptane to obtain a HOF dispersion liquid, and then the HOF dispersion liquid is uniformly mixed with a polybenzimidazole solution to obtain the first coating solution.

[0021] The second coating solution is prepared by the following method: a n-heptane solution of hydroxyvinyl silicone oil is uniformly mixed with a cross-linking agent and a catalyst to obtain the second coating solution.

[0022] Preferably, the temperature of the high-temperature cross-linking is 120-140°C.

[0023] Preferably, the time of the high-temperature cross-linking is 4-6 h. After the high-temperature cross-linking, the dichloromethane-resistant VOCs recovery organic membrane is obtained, and the activation process of the HOF is also completed in the high-temperature process.

[0024] Preferably, in the preparation method of the first coating solution, the mass ratio of the hydrogen-bond organic framework material to n-heptane is 2-10: 90-98.

[0025] Preferably, in the preparation method of the first coating solution, the solvent of the polybenzimidazole solution is DMAc, and more preferably, the mass ratio of polybenzimidazole to DMAc in the polybenzimidazole solution is 20-25:75-80.

[0026] Preferably, in the preparation method of the first coating solution, the mass ratio of the polybenzimidazole solution to the HOF dispersion solution is 5-10:90-95.

[0027] Preferably, in the preparation method of the second coating solution, the mass ratio of the hydroxy vinyl silicone oil to n-heptane is 7-12:88-93.

[0028] Preferably, in the preparation method of the second coating solution, the mass ratio of the cross-linking agent to the n-heptane solution of the hydroxy vinyl silicone oil is 1-4:6-9.

[0029] Preferably, in the preparation method of the second coating solution, the catalyst is 0.01-1% of the weight of the n-heptane solution of the hydroxy vinyl silicone oil.

[0030] Preferably, the cross-linking agent is tetraethoxysilane (TEOS), and the catalyst is tetrabutyl tin.

[0031] Preferably, the viscosity of the second coating solution is 18 mPa·s.

[0032] Further, the membrane material of the second membrane separation device is an organic matter preferentially permeable membrane. The active membrane layer material of the organic matter preferentially permeable membrane is at least one of polyoctylmethylsiloxane, polydimethylsiloxane, polypropylmethylsiloxane, polyphenylmethylsiloxane, or a modified polymer of the foregoing materials, and the support layer is polyether sulfone, polyvinylidene fluoride, polytetrafluoroethylene, or polyacrylonitrile. Such membrane material has preferential selectivity to organic matter and is suitable for processing low-concentration dichloromethane.

[0033] Further, the permeate side outlet of the second membrane separation device is connected to an adsorption device or a combustion device to ensure that the final discharged gas meets environmental standards.

[0034] The adsorption device uses activated carbon, resin, or other adsorbents to perform deep adsorption treatment on dichloromethane in the tail gas, ensuring that the concentration of dichloromethane in the discharged gas is below the detection limit.

[0035] Further, the material of the inlet flow channel spacer and the permeate side flow channel spacer of the first membrane separation device and the second membrane separation device is a flexible anti-static plastic grid material. This can effectively prevent the accumulation of electric charge and reduce the risk of static spark between the dichloromethane waste gas and the equipment.

[0036] The liquid phase outlet of the condensing device is connected to a liquid storage tank for collecting liquefied dichloromethane liquid.

[0037] Further, the permeation side of the first membrane separation device and the second membrane separation device is connected to a vacuum device. The vacuum device ensures that the permeation gas can be effectively collected and transported.

[0038] The utility model can adopt the prior art operation, also can use the following method to operate:

[0039] (1) the waste gas is sent into the inlet of the first membrane separation device at 8~12 kPa pressure, under the action of the pressure difference before and after the membrane, dichloromethane selectively permeates through the membrane layer, and the first permeation gas is formed, and the first retentate gas is obtained at the retentate side outlet of the first membrane separation;

[0040] (2) the first retentate gas is sent into the inlet of the second membrane separation device, under the action of the pressure difference before and after the membrane, dichloromethane selectively permeates through the membrane layer, and the second permeation gas is formed;

[0041] (3) the first permeation gas and the second permeation gas are sent into the condensing device, and are condensed under 0 DEG C condition, dichloromethane is collected at the liquid phase outlet of the condensing device, and the tail gas of the condensing device returns to the inlet of the first membrane separation device or the second membrane separation device for cascade treatment.

[0042] In step (1), the waste gas contains 10~20%v / v dichloromethane.

[0043] In step (2), the second retentate gas is obtained at the retentate side outlet of the second membrane separation, and the second retentate gas is subjected to adsorption or combustion treatment, so that the finally discharged gas meets the environmental standard. The second retentate gas contains 0.05~0.3%v / v dichloromethane.

[0044] In step (3), when the condensing device is a normal pressure condensing device, the dichloromethane concentration in the tail gas is about 20%v / v, and at this time, the tail gas returns to the inlet of the first membrane separation device for cascade treatment; when the condensing device is a compression condensing device, the dichloromethane concentration in the tail gas is 2.2~4.0%v / v, and at this time, the tail gas returns to the inlet of the second membrane separation device for cascade treatment.

[0045] The utility model has the advantages that:

[0046] (1) dichloromethane-resistant organic membranes and organic matter-priority permeation membranes are used, combined with a two-stage membrane separation system, to effectively improve the separation efficiency of dichloromethane in waste gas. Under the synergistic action of the first membrane separation device and the second membrane separation device, dichloromethane is gradually concentrated at different concentrations, and finally recovered through the condensing device. The overall recovery rate of the method can reach more than 90%, significantly improving the recovery efficiency of dichloromethane.

[0047] (2) Since the recovery rate of dichloromethane in the exhaust gas is high, the concentration of dichloromethane that is not recovered is very low, and the concentration of dichloromethane in the tail gas is controlled at a low level. Through efficient condensation and secondary cascade treatment of the condensing device, the final exhaust gas meets strict environmental standards, avoiding pollution to the atmospheric environment.

[0048] (3) Combined with cascade treatment design, energy waste is reduced, and the operation cost is low. Especially the use of condensing technology, not only can reduce energy consumption through atmospheric condensing device, but also can choose compression condensing device to optimize the recovery of dichloromethane, further improving the economy and operation flexibility.

[0049] (4) The system design is compact, the land occupation is small, the operation cost is low, and can be modularized combined according to different application scenes and needs, has good expansibility and adaptability. Especially suitable for the treatment of dichloromethane-containing exhaust gas in chemical industry, pharmaceutical industry, printing industry, new energy industry and the like. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a structure diagram of a system for recovering dichloromethane from exhaust gas adopted in example 1.

[0051] Figure 2 is a structure diagram of a system for recovering dichloromethane from exhaust gas adopted in example 2. DETAILED DESCRIPTION

[0052] The technical scheme of the utility model will be described in detail below in combination with specific embodiments. Example 1

[0053] A system for recovering dichloromethane from exhaust gas as shown in Figure 1 , the permeate side outlet of the first membrane separation device is connected with the inlet of the second membrane separation device, the permeate side outlet of the first membrane separation device and the permeate side outlet of the second membrane separation device are connected with the inlet of the condensing device, the condensing device is an atmospheric condensing device, and the tail gas outlet of the condensing device is connected with the inlet of the first membrane separation device.

[0054] A fan is further arranged at the inlet of the first membrane separation device. The fan is an explosion-proof centrifugal fan.

[0055] The compressor of the compression condensing device is a liquid injection screw compressor.

[0056] The membrane material of the first membrane separation device is a dichloromethane-resistant VOCs recovery organic membrane, which comprises a base film layer, an intermediate layer and an active layer arranged in sequence, the base film layer is polyvinylidene fluoride, the intermediate layer is polybenzimidazole dispersed with hydrogen-bonded organic framework material, and the active layer is crosslinked polydimethylsiloxane. The base film layer material is polyvinylidene fluoride, which has good mechanical strength and chemical stability; the intermediate layer is polybenzimidazole dispersed with hydrogen-bonded organic framework material, which enhances the selectivity and permeability of the membrane; and the active layer is crosslinked polydimethylsiloxane, which has high affinity for dichloromethane and can make dichloromethane preferentially permeate.

[0057] The hydrogen-bonded organic framework material is H IAM-JM; the hydrogen-bonded organic framework material is subjected to activation treatment, and the H IAM-JM is prepared by the following method:

[0058] The 2,2-dithiodibenzoic acid and acetic acid are uniformly dispersed in a ratio of 0.05-0.1 g:50-80 mL, and then reacted at 70-90°C under vacuum for 10-14 h to obtain the H IAM-JM.

[0059] The dichloromethane-resistant VOCs recovery organic membrane is prepared by the following method:

[0060] The first coating solution is coated on the base film, and after pre-drying, the second coating solution is coated thereon, and then crosslinked at high temperature to obtain the dichloromethane-resistant VOCs recovery organic membrane.

[0061] The first coating solution is prepared by the following method: the hydrogen-bonded organic framework material is ultrasonically oscillated in n-heptane to obtain a HOF dispersion liquid, and then the HOF dispersion liquid is uniformly mixed with a polybenzimidazole solution to obtain the first coating solution.

[0062] The second coating solution is prepared by the following method: a n-heptane solution of hydroxyvinyl silicone oil is uniformly mixed with a crosslinking agent and a catalyst to obtain the second coating solution.

[0063] The temperature of the high-temperature crosslinking is 120-140°C.

[0064] The time of the high-temperature crosslinking is 4-6 h. After high-temperature crosslinking, the dichloromethane-resistant VOCs recovery organic membrane is obtained, and the activation process of the HOF is also completed in the high-temperature process.

[0065] In the preparation method of the first coating solution, the mass ratio of the hydrogen-bonded organic framework material to n-heptane is 2-10:90-98.

[0066] In the preparation method of the first coating solution, the solvent of the polybenzimidazole solution is DMAc, and more preferably, the mass ratio of polybenzimidazole to DMAc in the polybenzimidazole solution is 20-25:75-80.

[0067] In the preparation method of the first coating solution, the mass ratio of the polybenzimidazole solution to the HOF dispersion solution is 5-10:90-95.

[0068] In the preparation method of the second coating solution, the mass ratio of the hydroxy vinyl silicone oil to the n-heptane is 7-12:88-93.

[0069] In the preparation method of the second coating solution, the mass ratio of the crosslinking agent to the n-heptane solution of the hydroxy vinyl silicone oil is 1-4:6-9.

[0070] In the preparation method of the second coating solution, the catalyst is 0.01-1% of the weight of the n-heptane solution of the hydroxy vinyl silicone oil.

[0071] The crosslinking agent is tetraethoxysilane (TEOS), and the catalyst is tetrabutyl tin.

[0072] The viscosity of the second coating solution is 18 mPa·s.

[0073] The membrane material of the second membrane separation device is a preferential organic matter membrane with a polyoctylmethylsiloxane active layer.

[0074] The retentate side outlet of the second membrane separation device is connected to an adsorption device.

[0075] The adsorption device uses activated carbon to perform deep adsorption treatment on dichloromethane in the tail gas.

[0076] The material of the inlet channel spacer and the permeation side channel spacer of the first membrane separation device and the second membrane separation device is a flexible anti-static plastic grid material.

[0077] The liquid phase outlet of the condensing device is connected to a liquid storage tank for collecting liquefied dichloromethane liquid.

[0078] The permeation side of the first membrane separation device and the second membrane separation device is connected to a vacuum device.

[0079] During operation, waste gas containing 20% ​​v / v dichloromethane is pressurized to 8 kPa and then fed into the first membrane separation unit by a fan. Dichloromethane selectively permeates through the first membrane separation unit, forming the first permeate gas (approximately 40% v / v dichloromethane); the gas that does not permeate through the membrane, as the first residual gas (approximately 5% v / v dichloromethane), enters the second membrane separation unit, where dichloromethane is further separated, forming the second permeate gas (approximately 15% v / v dichloromethane); the remaining gas, as the second residual gas, with the dichloromethane content reduced to 0.3% v / v, is then subjected to adsorption treatment to ensure that the final emission gas meets environmental standards. The first and second permeate gases are mixed and then enter an atmospheric pressure condenser, where they are condensed into liquid dichloromethane at 0°C and collected through a storage tank. The condensed non-condensable gas (approximately 20% v / v dichloromethane) is returned to the inlet of the first membrane separation unit for cascade treatment, ultimately achieving an overall dichloromethane recovery rate of 90.5%. Example 2

[0080] Adopting such Figure 2 The system shown is for recovering dichloromethane from exhaust gas. The only difference between this system and the system in Example 1 is that the condenser is a compression condenser and the permeate outlet of the second membrane separator is connected to the combustion device.

[0081] During operation, waste gas containing 10% v / v dichloromethane is pressurized to 12 kPa and then fed into the first membrane separation unit by a fan. Dichloromethane selectively permeates through the first membrane separation unit, forming the first permeate gas (approximately 30% v / v dichloromethane); the gas that does not permeate through the membrane, as the first residual gas (approximately 3% v / v dichloromethane), enters the second membrane separation unit, where dichloromethane is further separated, forming the second permeate gas (approximately 10% v / v dichloromethane); the remaining gas, as the second residual gas, with the dichloromethane content reduced to 0.05% v / v, is then subjected to combustion treatment to ensure that the final emission gas meets environmental standards. The first and second permeate gases are mixed and then enter a compression and condensation unit, where a liquid-injected screw compressor is used for compression. The compressor operates at a pressure range of 0.8 MPaG, and the compression process can be effectively controlled through the adjustment of the liquid injection system, avoiding energy waste caused by excessively high temperatures or low efficiency. The gas condenses into liquid dichloromethane at 0°C and is collected in a storage tank. The condensed non-condensable gas (approximately 2.2% v / v dichloromethane) is returned to the inlet of the second membrane separation unit for cascade treatment, ultimately achieving an overall dichloromethane recovery rate of 92%. Example 3

[0082] The same apparatus as in Example 2 was used, except that the membrane material of the first membrane separation device was polyperfluoroalkylvinylether. The waste gas containing 18% v / v dichloromethane was pressurized to 10 kPa and sent into the first membrane separation device by a blower. Dichloromethane selectively permeated through the first membrane separation device to form a first permeate gas (about 30% v / v dichloromethane); the gas that did not permeate through the membrane entered the second membrane separation device as a first retentate gas (about 7% v / v dichloromethane) to further separate dichloromethane to form a second permeate gas (about 10% v / v dichloromethane); the remaining gas, in which the content of dichloromethane was reduced to 0.3% v / v, was discharged as a second retentate gas, which was then treated by adsorption or combustion to ensure that the final discharged gas met the environmental standards. The first permeate gas and the second permeate gas were mixed and then entered the compression and condensation device, in which a liquid screw compressor was used for compression. The working pressure range of the compressor was 0.4 MPaG, and the gas compression process could be effectively controlled by adjusting the liquid injection system to avoid energy waste caused by excessively high temperature or low efficiency. The gas was condensed into liquid dichloromethane at 0°C and collected in a liquid storage tank. The non-condensable gas (about 4% v / v dichloromethane) after condensation was returned to the inlet of the second membrane separation device for cascade treatment, and the overall recovery rate of dichloromethane reached 87%. Example 4

[0083] The same apparatus as in Example 2 was used, except that the membrane material of the first membrane separation device was polyperfluoroalkylvinylether. The waste gas containing 18% v / v dichloromethane was pressurized to 10 kPa and sent into the first membrane separation device by a blower. Dichloromethane selectively permeated through the first membrane separation device to form a first permeate gas (about 30% v / v dichloromethane); the gas that did not permeate through the membrane entered the second membrane separation device as a first retentate gas (about 7% v / v dichloromethane) to further separate dichloromethane to form a second permeate gas (about 10% v / v dichloromethane); the remaining gas, in which the content of dichloromethane was reduced to 0.3% v / v, was discharged as a second retentate gas, which was then treated by adsorption or combustion to ensure that the final discharged gas met the environmental standards. The first permeate gas and the second permeate gas were mixed and then entered the compression and condensation device, in which a liquid screw compressor was used for compression. The working pressure range of the compressor was 0.4 MPaG, and the gas compression process could be effectively controlled by adjusting the liquid injection system to avoid energy waste caused by excessively high temperature or low efficiency. The gas was condensed into liquid dichloromethane at 0°C and collected in a liquid storage tank. The non-condensable gas (about 4% v / v dichloromethane) after condensation was returned to the inlet of the second membrane separation device for cascade treatment, and the overall recovery rate of dichloromethane reached 87%.

Claims

1. A system for recovering dichloromethane from waste gas, characterized in that, The osmotic outlet of the first membrane separation unit is connected to the inlet of the second membrane separation unit, and the osmotic outlets of the first and second membrane separation units are connected to the inlet of the condensation unit. When the condensing device is an atmospheric pressure condensing device, the exhaust gas outlet of the condensing device is connected to the inlet of the first membrane separation device. When the condensing device is a compression condensing device, the exhaust outlet of the condensing device is connected to the inlet of the second membrane separation device.

2. The system according to claim 1, characterized in that, A fan is also installed at the inlet of the first membrane separation device.

3. The system according to claim 2, characterized in that, The fan is an explosion-proof centrifugal fan or a vortex fan.

4. The system according to claim 1, characterized in that, The compressor of the compression condensation device is a liquid-injected screw compressor.

5. The system according to claim 1, characterized in that, The membrane material of the first membrane separation device is a mixed matrix membrane or a perfluoropolymer membrane. The mixed matrix membrane is at least one of polyoctylmethylsiloxane, polydimethylsiloxane, or polyphenylmethylsiloxane, and the perfluoropolymer membrane is polyperfluoroalkyl vinyl ether.

6. The system according to claim 1, characterized in that, The membrane material of the second membrane separation device is a membrane that preferentially permeates organic matter.

7. The system according to claim 6, characterized in that, The active membrane material of the preferred organic permeable membrane is at least one of polyoctylmethylsiloxane, polydimethylsiloxane, polypropylmethylsiloxane, polyphenylmethylsiloxane, or a modified polymer of the aforementioned materials, and the support layer is polyethersulfone, polyvinylidene fluoride, polytetrafluoroethylene, or polyacrylonitrile.

8. The system according to claim 1, characterized in that, The permeate side outlet of the second membrane separation device is connected to an adsorption device or a combustion device.

9. The system according to claim 1, characterized in that, The inlet flow channel partition and the permeate flow channel partition of the first membrane separation device and the second membrane separation device are made of flexible antistatic plastic mesh material.

10. The system according to claim 1, characterized in that, The liquid phase outlet of the condensation device is connected to a storage tank.

Images