Modified hollow fiber mixed matrix membrane and method for purifying hydrogen chloride

Abstract

The invention discloses a method for removing impurities such as CO2, CO, N2 and the like in HCl gas through membrane separation, a novel modified hollow fiber mixed matrix membrane is prepared, and an all-silicon molecular sieve and grafting modification are introduced, so that on one hand, the selectivity to CO2 and N2 molecules is enhanced, and on the other hand, the surface polarity of the hollow fiber membrane is reduced, and permeation of HCl is inhibited. In addition, the membrane material is subjected to surface modification through plasma, the bonding strength of the mixed matrix membrane is enhanced, and the permeation rate and selectivity of N2 and CO2 are further enhanced. According to the hollow fiber mixed matrix membrane, the purity of HCl can be improved to 99.5% or above.

Description

Technical Field

[0001] The invention relates to the technical field of membrane separation, and in particular to a modified hollow fiber mixed matrix membrane and a method for removing impurities from high-concentration hydrogen chloride gas. Background Art

[0002] Chlorine (Cl 2 ) is an important basic chemical and is widely used in the production of chemical raw materials, agricultural chemicals, building materials, pharmaceutical preparations and other products. However, in most chlorine-related reactions, the utilization rate of chlorine resources is very low, and chlorides mainly exist in the form of reaction intermediates and do not enter the final target product. Taking the production of isocyanates by phosgene as an example, after carbonyl substitution, most of the chlorine atoms are discharged in the form of hydrogen chloride.

[0003] At present, the most effective way to deal with by-product hydrogen chloride in industry is to directly convert it into chlorine gas for recycling. On the one hand, it can not only solve the production pressure brought to enterprises by a large amount of by-product hydrogen chloride, but also conform to the economic development model of resource recycling, which is crucial to promoting the sustainable development of chlorine-related industries and protecting the environment. Among them, the catalytic HCl oxidation method for chlorine production has many advantages such as simple operation, low energy consumption, no other side reactions, and high efficiency.

[0004] However, in the process of producing isocyanates by phosgene, the by-product hydrogen chloride contains a small amount of impurities such as carbon dioxide, carbon monoxide, and nitrogen. These impurities react in the HCl oxidation reactor to produce inert gas CO 2 With N 2 These inert gases will react with the unreacted HCl and O 2 , and Cl 2 , H 2 O gas is used to remove HCl and H 2 O removal, Cl 2 After refining, the remaining tail gas is O 2 Mainly, and contains a certain amount of CO 2 And a small amount of N 2 With Cl 2 In order to make full use of the O 2 In industry, part of the tail gas is usually recycled and the rest is discharged to avoid the inert gas CO 2 、N 2 Continuously enriched in the system, however, in order to maximize the O 2 In terms of utilization rate, in actual production, the circulating gas accounts for more than 90% of the total tail gas content, which also causes a significant enrichment of inert gas. Eventually, a large amount of inert gas enters the front end of the reactor and mixes with the raw gas, resulting in an increase of about 5-15% in the reactor's air intake load at the same output.

[0005] CN110508105B introduces a HCl / CO 2 The separation process of the mixed gas is realized by two-stage pressure distillation technology to separate CO 2 Separation from HCl. However, the maximum operating pressure in this method is 6MPa, and a two-stage compressor and distillation device are required, the process equipment investment cost and operating cost are large, and the purity of the HCl product is 91-99.9%, and the stability is poor. Summary of the invention

[0006] The present invention aims to provide a membrane separation method for removing CO from HCl gas. 2 ,CO,N 2 By preparing a novel modified hollow fiber mixed matrix membrane, the membrane is enhanced by introducing all-silicon molecular sieve and grafting modification to remove impurities such as CO 2 、N 2 On the one hand, the selectivity of the molecules is improved, and on the other hand, the surface polarity of the hollow fiber membrane is reduced to inhibit the penetration of HCl. In addition, the surface of the membrane material is modified by plasma to enhance the bonding strength of the mixed matrix membrane and further enhance the N 2 , CO 2 The hollow fiber mixed matrix membrane can increase the purity of HCl to more than 99.5%, significantly reduce the accumulated circulation volume in the HCl oxidation system, reduce the circulating inert gas content to less than 5% vol, reduce the reactor operating load under the same liquid chlorine output, and reduce the consumption of alkali solution for tail gas capture at the back end, thereby reducing production and operation costs.

[0007] To achieve the purpose, the present invention provides the following technical solutions:

[0008] First, the present invention provides a modified hollow fiber mixed matrix membrane, which is prepared by the following steps:

[0009] (S1) mixing a prepolymer, a grafting agent and a solvent in proportion, stirring and mixing at room temperature and pressure to obtain a prepolymer solution;

[0010] (S2) mixing the crosslinking agent and the catalyst with the prepolymer solution prepared in step S1, and continuously stirring and mixing to obtain a mixed solution;

[0011] (S3) mixing the molecular sieve powder, the surfactant and the mixed solution prepared in S2, and then performing ultrasonic dispersion, and vacuum degassing the obtained mixed solution to obtain a casting solution;

[0012] (S4) coating the casting solution prepared in S3 on the hollow fiber support, placing the hollow fiber support in an oven for heating and curing to form a hollow fiber mixed matrix membrane;

[0013] (S5) Using a normal pressure plasma cleaning machine to perform surface treatment on the hollow fiber mixed matrix membrane prepared in S4 to obtain a modified hollow fiber mixed matrix membrane.

[0014] In the preparation method, the prepolymer in step S1 is vinyl terminated polydimethylsiloxane; preferably, the viscosity of the prepolymer is 50-500 CST;

[0015] The grafting agent in step S1 is one of hexadecyltrimethoxysilane (CTMS), perfluorooctyltriethoxysilane (FOTS), and polyaniline (PANI), preferably CTMS;

[0016] The type of the solvent described in step S1 is: one or more of dichloromethane, chloroform, toluene, n-hexane, cyclohexane, and ethanol, preferably cyclohexane;

[0017] The mass ratio of the prepolymer to the grafting agent and the solvent in step S1 is 1:(0.01-0.2):(0.5-20), preferably 1:(0.05-0.1):(1-10).

[0018] In the preparation method, the cross-linking agent in step S2 is 1,3,5-benzenetricarboxylic acid chloride, and the mass ratio of the cross-linking agent to the prepolymer is 0.1-1:1, preferably 0.1-0.5:1;

[0019] The catalyst in step S2 is a platinum catalyst (e.g., SYL-OFF 4000), and the mass ratio of the catalyst to the prepolymer is 0.001-0.05:1;

[0020] The stirring and mixing temperature is 0-30°C and the time is 0.5-5h.

[0021] In the preparation method, the molecular sieve described in step S3 mainly includes S-1, HS-500, ZSM-5, ZSM-12, MCM-41, TS-1, preferably HS-500 molecular sieve;

[0022] The surfactant described in step S3 is at least one of sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and polyoxyethylene alkyl ether (Brij), preferably SDS;

[0023] The mass ratio of the mixed solution, molecular sieve powder and surfactant described in step S3 is 1:(0.01-0.5):(0.01-0.1), preferably 1:(0.05-0.2):(0.02-0.05);

[0024] The vacuum degassing time described in step S3 is 0.1-2h.

[0025] In the preparation method, the hollow fiber carrier material in step S4 includes one of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polysulfone (PSF), and polytetrafluoroethylene (PTFE), preferably PVDF;

[0026] The heating curing temperature in step S4 is 80-150° C. and the time is 5-30 hours.

[0027] In the preparation method, the operating conditions of the plasma treatment described in step S5 are: the power of the plasma spray gun is 0.5-1KW, the distance between the spray gun and the film surface is 5-20cm, and the plasma treatment time is 10s-120s.

[0028] In another aspect, the present invention provides a method for separating a small amount of CO 2 ,CO,N 2 A method for further purifying high-concentration HCl gas, the purification method comprising the steps of:

[0029] The modified hollow fiber mixed matrix membrane is used as a membrane separation component, containing a small amount of CO 2 ,CO,N 2 The crude HCl gas with impurities enters from the high pressure side, making the CO 2 ,CO,N 2 The gas enters the low-pressure side through the membrane assembly to remove the impurities in the raw material, which can make the CO in HCl 2 ,CO,N 2 The removal rate reaches more than 90%;

[0030] The crude HCl gas composition includes: 95-99% vol HCl, 0.5-2.5% vol CO 2 ,0.1-0.5%volCO,0.1-2%volN 2 ;

[0031] In the membrane separation process, the pressure on the high-pressure side is 0.3-1.0 MPaG, and the pressure on the low-pressure side is 0-0.2 MPaG;

[0032] The membrane separation operating temperature is room temperature;

[0033] The CO 2 ,CO,N 2 After the crude HCl gas passes through the membrane module, CO 2 The content was reduced to below 0.2% vol, the CO content was reduced to below 0.1% vol, and the N 2The content is reduced to below 0.2% vol, and the HCl content is increased to above 99.5%; the gas composition on the low-pressure side is: 10-50% vol HCl, 35-45% vol CO 2 , 3-9%vol CO, 5-40%vol N 2 .

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention removes most of the CO in the HCl raw gas through membrane separation technology. 2 ,CO,N 2 , reduce the total amount of inert gas entering the system, and recycle most of the O in the reaction tail gas 2 At the same time, the enrichment of inert gas can be avoided to a great extent, thereby reducing the overall intake load under the same chlorine production. In addition, by pre- 2 , CO can be separated, and the consumption of alkali solution in the back-end exhaust gas treatment can be reduced, thereby reducing production costs. DETAILED DESCRIPTION

[0036] In order to understand the technical features and contents of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described here.

[0037] Unless otherwise specified, the experimental procedures used in the following examples are all conventional methods.

[0038] <Source of raw materials>

[0039] Hydrogen chloride raw gas: photochemical process of Wanhua Chemical's isocyanate unit;

[0040] Polyvinylidene fluoride hollow fiber tube: Guangzhou Jinrongtao Environmental Protection Technology Co., Ltd.;

[0041] HS-500 molecular sieve, powder, Inokite;

[0042] Sodium lauryl sulfate: 99%, Inokane;

[0043] Hexadecyltrimethoxysilane: 95%, Inokane;

[0044] 1,3,5-Benzenetricarboxylic acid chloride: 98%, MacLean;

[0045] Cyclohexane: 99.5%, MacLean;

[0046] Vinyl terminated polydimethylsiloxane: PMX200-100, Dow Corning;

[0047] Platinum catalyst: SYL-OFF 4000, Dow Corning;

[0048] Atmospheric pressure plasma cleaning machine: jet-type AP plasma treatment system, Shenzhen Chengfeng Intelligent Manufacturing Co., Ltd.;

[0049] In the present invention, the separation ability of the modified hollow fiber mixed matrix membrane is evaluated by tracking the gas phase HCl content in the original mixed gas after separation and the content of each component on the low pressure side after separation.

[0050] Example 1

[0051] The hollow fiber membrane was prepared as follows:

[0052] (1) vinyl-terminated polydimethylsiloxane, hexadecyltrimethoxysilane and cyclohexane were weighed in a mass ratio of 1:0.1:3, and stirred and mixed at room temperature and pressure for 30 minutes;

[0053] (2) weighing the crosslinking agent and the catalyst according to the mass ratio of vinyl-terminated polydimethylsiloxane: 1,3,5-benzenetricarboxylic acid chloride: SYL-OFF 4000 platinum catalyst of 1:0.2:0.01, adding them to the vinyl-terminated polydimethylsiloxane solution, and stirring the reaction at 15° C. for 4 hours;

[0054] (3) The mixed solution, HS-500 molecular sieve powder and sodium dodecyl sulfate were mixed in a mass ratio of 1:0.15:0.03, and dispersed using ultrasound for 1 hour;

[0055] (4) placing the mixed solution into a vacuum drying oven and degassing at 50° C. for 2 h to obtain a casting solution;

[0056] (5) coating the casting solution on the surface of the PVDF hollow fiber tube, reacting at 110° C. for 12 h to obtain a hollow fiber mixed matrix membrane;

[0057] (6) The hollow fiber mixed matrix membrane was surface treated using a normal pressure plasma cleaning machine. The power of the plasma gun was controlled to be 0.8 kW, the distance between the plasma gun and the membrane surface was 5 cm, and the plasma treatment time was 60 s to obtain a modified hollow fiber mixed matrix membrane.

[0058] The modified hollow fiber mixed matrix membrane was used to treat and purify the HCl raw gas produced as a byproduct of the photochemical process of the isocyanate device. The HCl raw gas composition was: 95.7% vol HCl, 2.1% vol CO 2 、0.4%volCO、1.8%volN 2 ;

[0059] The membrane separation conditions are: high pressure side pressure 0.5MPaG, low pressure side pressure 0.2MPaG, HCl raw gas is fed from the high pressure side, the separation temperature is room temperature, and after membrane separation, the high pressure side outlet gas composition is: 99.65% vol HCl, 0.12% vol CO 2 ,0.07%vol CO,0.16%vol N 2 The gas composition at the low pressure outlet is: 20.65% vol HCl, 39.72% vol CO 2 , 6.67%vol CO, 32.96%vol N 2 .

[0060] After membrane separation and purification, the inert gas (CO 2 、N 2 ) concentration dropped to 3.83% vol.

[0061] Example 2

[0062] The hollow fiber membrane was prepared as follows:

[0063] (1) Weigh vinyl-terminated polydimethylsiloxane, perfluorooctyltriethoxysilane and dichloromethane in a mass ratio of 1:0.05:10, and stir and mix at room temperature and pressure for 30 minutes;

[0064] (2) weighing the crosslinking agent and the catalyst according to the mass ratio of vinyl-terminated polydimethylsiloxane: 1,3,5-benzenetricarboxylic acid chloride: SYL-OFF 4000 platinum catalyst of 1:0.8:0.003, adding them to the vinyl-terminated polydimethylsiloxane solution, and stirring the reaction at 20° C. for 4 hours;

[0065] (3) The mixed solution, TS-1 molecular sieve powder and hexadecyltrimethylammonium bromide were mixed in a mass ratio of 1:0.05:0.05, and dispersed using ultrasound for 1 hour;

[0066] (4) placing the mixed solution into a vacuum drying oven and degassing at 50° C. for 2 h to obtain a casting solution;

[0067] (5) coating the casting solution on the surface of the PAN hollow fiber tube and reacting it at 110° C. for 24 h to obtain a hollow fiber mixed matrix membrane;

[0068] (6) The hollow fiber mixed matrix membrane was surface treated using a normal pressure plasma cleaning machine. The power of the plasma gun was controlled to be 0.5 kW, the distance between the plasma gun and the membrane surface was 10 cm, and the plasma treatment time was 30 s to obtain a modified hollow fiber mixed matrix membrane.

[0069] The modified hollow fiber mixed matrix membrane was used to treat and purify the HCl raw gas produced as a byproduct of the photochemical process of the isocyanate device. The HCl raw gas composition was: 95.7% vol HCl, 2.1% vol CO 2 、0.4%volCO、1.8%volN 2 ;

[0070] The membrane separation conditions are: high pressure side pressure 0.5MPaG, low pressure side pressure 0.2MPaG, HCl raw gas is fed from the high pressure side, the separation temperature is room temperature, and after membrane separation, the high pressure side outlet gas composition is: 99.56% vol HCl, 0.17% vol CO 2 ,0.09%vol CO,0.18%vol N 2 The gas composition at the low pressure outlet is: 22.36% vol HCl, 38.77% vol CO 2 , 6.29%vol CO, 32.58%vol N 2 .

[0071] After membrane separation and purification, the inert gas (CO 2 、N 2 ) concentration dropped to 4.22% vol.

[0072] Example 3

[0073] The hollow fiber membrane was prepared as follows:

[0074] (1) Weigh vinyl-terminated polydimethylsiloxane, hexadecyltrimethoxysilane and n-hexane in a mass ratio of 1:0.15:7, and stir and mix at room temperature and pressure for 30 minutes;

[0075] (2) weighing the crosslinking agent and the catalyst according to the mass ratio of vinyl-terminated polydimethylsiloxane: 1,3,5-benzenetricarboxylic acid chloride: SYL-OFF 4000 platinum catalyst of 1:0.5:0.045, adding the crosslinking agent and the catalyst to the vinyl-terminated polydimethylsiloxane solution, and stirring the reaction at 25° C. for 3 hours;

[0076] (3) The mixed solution, S-1 molecular sieve powder and sodium dodecyl sulfate were mixed in a mass ratio of 1:0.02:0.07, and dispersed using ultrasound for 1 hour;

[0077] (4) placing the mixed solution into a vacuum drying oven and degassing at 50° C. for 2 h to obtain a casting solution;

[0078] (5) coating the casting solution on the surface of the PSF hollow fiber tube and reacting it at 120° C. for 15 h to obtain a hollow fiber mixed matrix membrane;

[0079] (6) The hollow fiber mixed matrix membrane was surface treated using a normal pressure plasma cleaning machine. The power of the plasma gun was controlled to be 0.9 kW, the distance between the plasma gun and the membrane surface was 15 cm, and the plasma treatment time was 100 s to obtain a modified hollow fiber mixed matrix membrane.

[0080] The modified hollow fiber mixed matrix membrane was used to treat and purify the HCl raw gas produced as a byproduct of the photochemical process of the isocyanate device. The HCl raw gas composition was: 95.7% vol HCl, 2.1% vol CO 2 、0.4%volCO、1.8%volN 2 ;

[0081] The membrane separation conditions are: high pressure side pressure 0.5MPaG, low pressure side pressure 0.2MPaG, HCl raw gas is fed from the high pressure side, the separation temperature is room temperature, and after membrane separation, the high pressure side outlet gas composition is: 99.50% vol HCl, 0.21% vol CO 2 ,0.09%vol CO,0.20%vol N 2 The gas composition at the low pressure outlet is: 23.50% vol HCl, 38.01% vol CO 2 , 6.29%vol CO, 32.20%vol N 2 .

[0082] After membrane separation and purification, the inert gas (CO 2 、N 2 ) concentration dropped to 4.83% vol.

[0083] Comparative Example 1

[0084] The hollow fiber membrane was prepared as follows:

[0085] (1) Weigh vinyl-terminated polydimethylsiloxane, hexadecyltrimethoxysilane and cyclohexane in a mass ratio of 1:0.1:3, and stir and mix at room temperature and pressure for 30 minutes;

[0086] (2) weighing the crosslinking agent and the catalyst according to the mass ratio of vinyl-terminated polydimethylsiloxane: 1,3,5-benzenetricarboxylic acid chloride: SYL-OFF 4000 platinum catalyst of 1:0.2:0.01, adding them to the vinyl-terminated polydimethylsiloxane solution, and stirring the reaction at 15° C. for 4 hours;

[0087] (3) The mixed solution, HS-500 molecular sieve powder and sodium dodecyl sulfate were mixed in a mass ratio of 1:0.15:0.03, and dispersed using ultrasound for 1 hour;

[0088] (4) placing the mixed solution into a vacuum drying oven and degassing at 50° C. for 2 h to obtain a casting solution;

[0089] (5) The casting solution was coated on the surface of the PVDF hollow fiber tube and reacted at 110° C. for 12 h to obtain a hollow fiber mixed matrix membrane.

[0090] The hollow fiber mixed matrix membrane prepared above was used to treat and purify the HCl raw gas produced as a byproduct of the photochemical process of the isocyanate device. The HCl raw gas composition was: 95.7% vol HCl, 2.1% vol CO 2 、0.4%volCO、1.8%volN 2 ;

[0091] The membrane separation conditions are as follows: the high-pressure side pressure is 0.5 MPaG, the low-pressure side pressure is 0.2 MPaG, the HCl raw gas is fed from the high-pressure side, and the separation temperature is room temperature. After membrane separation, the high-pressure side outlet gas composition is: 98.12% vol HCl, 0.84% ​​vol CO 2 ,0.25%vol CO,0.79%vol N 2 The composition of the low-pressure outlet gas is: 49.72% vol HCl, 26.04% vol CO 2 , 3.25%vol CO, 20.99%vol N 2 .

[0092] After membrane separation and purification, the inert gas (CO 2 、N 2 ) concentration dropped to 13.97% vol.

[0093] Comparative Example 2

[0094] The hollow fiber membrane was prepared as follows:

[0095] (1) Weigh vinyl-terminated polydimethylsiloxane, hexadecyltrimethoxysilane and cyclohexane in a mass ratio of 1:0.1:3, and stir and mix at room temperature and pressure for 30 minutes;

[0096] (2) weighing the crosslinking agent and the catalyst according to the mass ratio of vinyl-terminated polydimethylsiloxane: 1,3,5-benzenetricarboxylic acid chloride: SYL-OFF 4000 platinum catalyst of 1:0.2:0.01, adding them to the vinyl-terminated polydimethylsiloxane solution, and stirring the reaction at 15° C. for 4 hours;

[0097] (3) placing the mixed solution in a vacuum drying oven and degassing at 50° C. for 2 h to obtain a casting solution;

[0098] (4) coating the casting solution on the surface of the PVDF hollow fiber tube and reacting at 110° C. for 12 h to obtain a hollow fiber mixed matrix membrane;

[0099] (5) The hollow fiber mixed matrix membrane was surface treated using a normal pressure plasma cleaning machine. The power of the plasma gun was controlled to be 0.8 kW, the distance between the plasma gun and the membrane surface was 5 cm, and the plasma treatment time was 60 s to obtain a modified hollow fiber mixed matrix membrane.

[0100] The modified hollow fiber mixed matrix membrane was used to treat and purify the HCl raw gas produced as a byproduct of the photochemical process of the isocyanate device. The HCl raw gas composition was: 95.7% vol HCl, 2.1% vol CO 2 、0.4%volCO、1.8%volN 2 ;

[0101] The membrane separation conditions are as follows: the high-pressure side pressure is 0.5 MPaG, the low-pressure side pressure is 0.2 MPaG, the HCl raw gas is fed from the high-pressure side, the separation temperature is room temperature, and after membrane separation, the high-pressure side outlet gas composition is: 97.34% vol HCl, 1.25% vol CO 2 ,0.28%vol CO,1.13%vol N 2 The composition of the low-pressure outlet gas is: 64.54% vol HCl, 18.25% vol CO 2 , 2.68%vol CO, 14.53%vol N 2 .

[0102] After membrane separation and purification, the inert gas (CO 2 、N 2 ) concentration dropped to 19.72% vol.

[0103] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A modified hollow fiber mixed matrix membrane, the preparation method of which comprises the following steps: (S1) stirring and mixing a prepolymer, a grafting agent and a solvent at room temperature and pressure to obtain a prepolymer solution; (S2) mixing a cross-linking agent and a catalyst with the prepolymer solution prepared in step S1 to obtain a mixed solution; (S3) mixing the molecular sieve powder, the surfactant and the mixed solution prepared in S2, and then performing ultrasonic dispersion, and vacuum degassing the obtained mixed solution to obtain a casting solution; (S4) coating the casting solution prepared in S3 on the hollow fiber support, heating and curing, and forming a hollow fiber mixed matrix membrane; (S5) Using a normal pressure plasma cleaning machine to perform surface treatment on the hollow fiber mixed matrix membrane prepared in S4 to obtain a modified hollow fiber mixed matrix membrane.

2. The modified hollow fiber mixed matrix membrane according to claim 1, wherein The prepolymer in step S1 is vinyl terminated polydimethylsiloxane; preferably, the viscosity of the prepolymer is 50-500 CST; and / or The grafting agent is one of hexadecyltrimethoxysilane (CTMS), perfluorooctyltriethoxysilane (FOTS), and polyaniline (PANI); and / or The solvent is one or more of dichloromethane, chloroform, toluene, n-hexane, cyclohexane and ethanol.

3. The modified hollow fiber mixed matrix membrane according to claim 1 or 2, wherein: In step S1, the mass ratio of the prepolymer to the grafting agent and the solvent is 1:(0.01-0.2):(0.5-20), preferably 1:(0.05-0.1):(1-10).

4. The modified hollow fiber mixed matrix membrane according to any one of claims 1 to 3, wherein: The cross-linking agent in step S2 is 1,3,5-benzenetricarboxylic acid chloride, and the mass ratio of the cross-linking agent to the prepolymer is 0.1-1:1, preferably 0.1-0.5:1; and / or The catalyst described in step S2 is a platinum catalyst, and the mass ratio of the catalyst to the prepolymer is 0.001-0.05:

1.

5. The modified hollow fiber mixed matrix membrane according to any one of claims 1 to 4, wherein: The molecular sieve described in step S3 includes at least one of S-1, HS-500, ZSM-5, ZSM-12, MCM-41, and TS-1; The surfactant is at least one of sodium lauryl sulfate, hexadecyltrimethylammonium bromide, polyethylene glycol, and polyoxyethylene alkyl ether; Preferably, the mass ratio of the mixed solution to the molecular sieve powder and the surfactant is 1:(0.01-0.5):(0.01-0.1), preferably 1:(0.05-0.2):(0.02-0.05).

6. The modified hollow fiber mixed matrix membrane according to any one of claims 1 to 5, wherein: The hollow fiber carrier material in step S4 includes one of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polysulfone (PSF), and polytetrafluoroethylene (PTFE), preferably PVDF; Preferably, the heating curing temperature in step S4 is 80-150° C. and the time is 5-30 hours.

7. The modified hollow fiber mixed matrix membrane according to any one of claims 1 to 6, wherein: The operating conditions of the plasma treatment described in step S5 are: plasma spray gun power 0.5-1KW, the distance between the spray gun and the film surface is 5-20cm, and the plasma treatment time is 10s-120s.

8. A method for purifying HCl gas, comprising: The modified hollow fiber mixed matrix membrane according to any one of claims 1 to 7 is used as a membrane separation component, and crude HCl gas containing a small amount of CO2, CO, and N2 impurities enters from the high-pressure side, so that the CO2, CO, and N2 therein enter the low-pressure side through the membrane component, thereby achieving the removal of impurity gases in the raw material.

9. The method according to claim 8, wherein: The crude HCl gas composition includes: 95-99% vol HCl, 0.5-2.5% vol CO2, 0.1-0.5% vol CO, 0.1-2% vol N2.

10. The method according to claim 8 or 9, wherein: In the membrane separation process, the pressure on the high-pressure side is 0.3-1.0 MPaG, and the pressure on the low-pressure side is 0-0.2 MPaG; The membrane separation operating temperature is room temperature.