A method for continuous defluorination of industrial hydrogen chloride tail gas

Abstract

This invention relates to a method for continuous defluorination of industrial hydrogen chloride tail gas. It employs a loop reactor, where hydrogen chloride and a liquid defluorinating agent are mixed via external gas and liquid circulation loops at a Venturi nozzle at the bottom of the reactor before being injected into the reactor. A static mixer is installed inside the reactor, where the materials flow at high speed, ensuring thorough mixing of the gas and liquid phases. This invention, when used in conjunction with a suitable defluorinating agent composition, including a chlorosilane defluorinating agent and a catalyst, can significantly shorten the defluorination treatment time and enable continuous defluorination operations, making it suitable for industrial applications. This invention can reduce the hydrogen fluoride content in hydrogen chloride tail gas to below 5 ppm, offering advantages such as simple operation, environmental friendliness, high defluorination capacity of the defluorinating agent, long service life, and low cost.

Description

Technical Field

[0001] This invention relates to a method for continuous defluorination of hydrogen fluoride from industrial hydrogen chloride tail gas, belonging to the field of chemical technology. Background Technology

[0002] The fluorochemical industry, primarily producing refrigerant products, has experienced rapid development in recent years. However, fluorochemical production generates a large amount of hydrochloric acid, a byproduct containing hydrogen fluoride. The presence of hydrogen fluoride in hydrochloric acid significantly increases its corrosiveness, limiting its application and severely impacting its economic benefits. Therefore, the need to treat hydrogen fluoride in hydrochloric acid is becoming increasingly urgent, necessitating the search for a low-cost, high-efficiency defluorination method.

[0003] Currently, the main defluorination methods used by enterprises include precipitation, distillation, adsorption, and membrane separation. Based on the different defluorination processes, they can be divided into dry defluorination and wet defluorination. Dry defluorination utilizes solid defluorinating agents to selectively absorb HF impurities in the byproduct HCl gas. Solid defluorinating agents reported in the literature include Al2O3, SiO2, CaCl2, and CaO. However, dry defluorination has two problems: first, the defluorination capacity of dry defluorinating agents is generally low, resulting in high usage costs; second, the defluorinating agent generates a large amount of solid waste after its deterioration, increasing environmental concerns. Wet defluorination utilizes solvents to selectively adsorb HF impurities in the byproduct HCl. The solvent used can be recycled after the impurities are removed.

[0004] JPS63241806A discloses a method for defluorination using dimethyldichlorosilane. In this method, 800 ml of 32% hydrochloric acid containing 116.4 ppm hydrogen fluoride and 1.8 g of dimethyldichlorosilane are added to a polyethylene reaction flask. After stirring for 24 hours, and separating the organic layer, the hydrogen fluoride content in the hydrochloric acid is 0.7 ppm, resulting in a hydrogen fluoride removal rate of 99.4%. If 0.3 g of dimethyldichlorosilane is used, the hydrogen fluoride concentration in the hydrochloric acid is 13 ppm, and the hydrogen fluoride removal rate is 88.8%. However, this method suffers from the problem of excessively long defluorination time; furthermore, dimethyldichlorosilane has a low boiling point (70°C) and is prone to volatilization and loss, posing certain safety risks.

[0005] CN103910332A discloses a method for purifying hydrogen chloride using anhydrous chlorosilanes. This method uses chlorosilane R... n SiCl （4-n） Using HF adsorbent, where R is methyl, phenyl, ethyl, butyl, or a mixture thereof, hydrogen chloride to be treated is purified through a chemical reaction. Defluorination is achieved by heating and pressurizing in a stirred reactor for an extended period, resulting in a hydrogen fluoride removal rate exceeding 90%. However, this method suffers from the limitation of not being suitable for continuous processing. Summary of the Invention

[0006] In view of the above-mentioned state of the prior art, the present invention has conducted in-depth and extensive research in the field of industrial hydrogen chloride tail gas defluorination and found that using a loop reactor that enhances the gas-liquid two-phase mixing effect as a defluorination device, and adding a static mixer inside the reactor to further enhance the gas-liquid two-phase mixing effect, can greatly improve the defluorination efficiency; in combination with a suitable defluorination agent composition, including chlorosilane defluorinating agent and catalyst, the defluorination treatment time can be greatly shortened and the defluorination operation can be made continuous, which is suitable for industrial application.

[0007] Therefore, the objective of this invention is to provide a method for the continuous defluorination of industrial hydrogen chloride tail gas. Based on a dual-circulation mixing system employing a hydrogen chloride gas circulation loop and a defluorinating agent liquid circulation loop, a static mixer is added in the middle of the reactor to promote the mixing and exchange between the hydrogen chloride tail gas and the defluorinating agent. Furthermore, the use of an optimized defluorinating agent composition can significantly accelerate the rate of fluorine substitution for chlorine and effectively suppress the volatilization of fluorinated organic compounds, resulting in a purer treated hydrogen chloride tail gas and achieving optimal defluorination performance.

[0008] The technical solution for achieving the above-mentioned objectives can be summarized as follows:

[0009] A method for continuous defluorination of industrial hydrogen chloride tail gas includes using an apparatus for continuous defluorination of industrial hydrogen chloride tail gas and a defluorinating agent composition, wherein the defluorinating agent composition is placed in the apparatus for continuous defluorination of industrial hydrogen chloride tail gas to carry out a continuous defluorination reaction.

[0010] The aforementioned device for continuous defluorination of industrial hydrogen chloride tail gas includes a static mixer. One end of the static mixer is sequentially connected to a gas-liquid separator, a condenser, and a hydrogen chloride gas outlet. The other end of the static mixer is connected to a Venturi nozzle. The gas-liquid separator is connected to a liquid circulation loop and a gas circulation loop. The gas circulation loop is provided with a hydrogen chloride gas inlet and is connected to the Venturi nozzle. The liquid circulation loop is connected to the Venturi nozzle through a circulation pump.

[0011] The defluorinating agent composition comprises a chlorosilane with a molecular weight greater than 150 and a catalyst, wherein the catalyst is a tertiary amine alkane with a molecular weight greater than 150.

[0012] According to the present invention, preferably, the defluorination temperature is 10~100℃, more preferably 50~80℃; and the defluorination pressure is 0.1~5MPa, more preferably 0.5~2MPa.

[0013] According to the present invention, preferably, the chlorosilane is a trichlorosilane or / and a dichlorosilane with a molecular weight higher than 150, having the general formula R n SiCl （4-n）n is 1 or 2, and R is pentyl, phenyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylpentyl, dimethylbenzene, trimethylbenzene, or diethylbenzene.

[0014] According to the present invention, preferably, the catalyst is a tertiary amine alkane with a molecular weight higher than 150, having the general formula R`3N, where R` is phenyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, benzyl, phenethyl, phenylpropyl, phenylbutyl or phenylpentyl.

[0015] According to the present invention, preferably, the amount of catalyst added to the defluorinating agent composition is 1‰ to 5% of the mass of the defluorinating agent composition, more preferably 0.5% to 2%.

[0016] According to the present invention, preferably, the static mixer is a cylindrical structure, and the cylindrical structure is provided with one or more perforated plates, more preferably 3-9; preferably, the perforated plates are arranged radially along the cylinder or at an angle to the radial direction.

[0017] Preferably, the aspect ratio of the static mixer is 100:1 to 10.

[0018] According to the present invention, preferably, a gas check valve is provided between the hydrogen chloride gas inlet and the gas-liquid separation device.

[0019] According to the present invention, preferably, a buffer zone is also provided between the static mixer and the venturi nozzle.

[0020] According to the present invention, preferably, the device for continuous defluorination of industrial hydrogen chloride tail gas is a column reactor structure. The column reactor is divided into three sections: a buffer section, a mixing section, and a separation section. The buffer section is the buffer section, the static mixer and Venturi nozzle are the mixing section, and the gas-liquid separator and condenser are the separation section.

[0021] According to the present invention, preferably, at least one of the buffer zone, static mixer, venturi nozzle and gas-liquid separation device is provided with a heating device for heating the defluorination reaction.

[0022] According to the present invention, preferably, the device for continuous defluorination of industrial hydrogen chloride tail gas is a closed pressure device that can adapt to high-pressure reactions.

[0023] According to the present invention, a preferred embodiment of a method for continuous defluorination of industrial hydrogen chloride tail gas includes the following steps:

[0024] A defluorinating agent composition is added to the device for continuous defluorination of industrial hydrogen chloride tail gas beforehand. The circulation pump is started, and the device is heated to the preset temperature after the liquid forms a circulation loop. Industrial hydrogen chloride tail gas is then introduced into the device through the hydrogen chloride gas inlet. The gas enters the buffer zone through the gas circulation loop and the Venturi nozzle. The defluorinating agent composition enters the buffer zone through the liquid circulation loop, the circulation pump, and the Venturi nozzle. The hydrogen chloride tail gas and the defluorinating agent composition are mixed in the buffer zone and then enter the static mixer simultaneously. Then they enter the gas-liquid separation device. The separated hydrogen chloride gas is condensed by the condenser and discharged from the hydrogen chloride outlet.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. High reaction efficiency. This invention, based on a dual-circulation mixing system of hydrogen chloride gas and defluorinating agent liquid, further enhances the mixing and exchange between the hydrogen chloride tail gas and the defluorinating agent composition by adding a static mixer in the middle of the device. This significantly improves the gas-liquid two-phase mixing effect and greatly increases defluorination efficiency. Simultaneously, the defluorinating agent composition promotes the rate of fluorine substitution for chlorine and effectively inhibits the volatilization of fluorinated organic compounds, resulting in purer treated hydrogen chloride tail gas. This invention achieves highly efficient defluorination through continuous operation, with a hydrogen fluoride removal rate exceeding 97% under continuous operating conditions.

[0027] 2. Simple process. This invention can achieve continuous operation without additional steps, significantly simplifying the operation process and allowing for long continuous operation time.

[0028] 3. Low cost and good economic efficiency. The defluorinating agent composition in this invention has a low cost, which is significantly more cost-effective than dry defluorination.

[0029] 4. Green and environmentally friendly. The defluorinating agent composition of this invention can be recycled after long-term use, reducing the problem of solid waste treatment caused by dry defluorination. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the main structure of the device for continuous defluorination of industrial hydrogen chloride tail gas according to the present invention.

[0031] Figure 2 This is a schematic diagram of the main structure of the static mixer of the present invention.

[0032] The components are: 1. Hydrogen chloride gas outlet, 2. Condenser, 3. Gas-liquid separation device, 4. Liquid circulation loop, 5. Static mixer, 6. Buffer zone, 7. Circulation pump, 8. Venturi nozzle, 9. Gas circulation loop, 10. Hydrogen chloride gas inlet, 11. Gas check valve, 12. Orifice plate. Detailed Implementation

[0033] This invention, based on a dual-circulation mixing system of hydrogen chloride gas and defluorinating agent liquid, promotes the mixing and exchange of hydrogen chloride tail gas and defluorinating agent by adding a static mixer in the middle of the reactor. Furthermore, the use of an optimized defluorinating agent composition can significantly accelerate the rate of fluorine substitution for chlorine and effectively suppress the volatilization of fluorinated organic compounds, resulting in purer treated hydrogen chloride tail gas and achieving optimal defluorination performance.

[0034] The present invention provides a method for continuous defluorination of industrial hydrogen chloride tail gas, comprising an apparatus for continuous defluorination of industrial hydrogen chloride tail gas and a defluorinating agent composition; and placing the defluorinating agent composition in the apparatus for continuous defluorination of industrial hydrogen chloride tail gas to carry out a continuous defluorination reaction.

[0035] The device for continuous defluorination of industrial hydrogen chloride tail gas includes a static mixer 5. One end of the static mixer 5 is sequentially connected to a gas-liquid separator 3, a condenser 2, and a hydrogen chloride gas outlet 1. The other end of the static mixer 5 is connected to a Venturi nozzle 8. The gas-liquid separator 3 is connected to a liquid circulation loop 4 and a gas circulation loop 9. The gas circulation loop 9 is provided with a hydrogen chloride gas inlet 10 and is connected to the Venturi nozzle 8. The liquid circulation loop 4 is connected to the Venturi nozzle 8 through a circulation pump 7.

[0036] The defluorinating agent composition comprises a chlorosilane with a molecular weight greater than 150 and a catalyst, wherein the catalyst is a tertiary amine alkane with a molecular weight greater than 150.

[0037] According to the present invention, the defluorinating agent composition comprises a chlorosilane and a catalyst. The chlorosilane reacts with hydrogen fluoride to remove hydrogen fluoride. The addition of a tertiary amine alkane catalyst can greatly promote the substitution of chlorine by fluorine on silicon, accelerate the rate of fluorine-chlorine substitution, lower the reaction temperature to achieve the same effect, and inhibit the volatilization of organofluorine compounds.

[0038] According to the present invention, the defluorination reaction can be carried out at a certain temperature and pressure. In one or more preferred embodiments, the defluorination temperature is 10~100℃, more preferably 50~80℃; the defluorination pressure is 0.1~5MPa, more preferably 0.5~2MPa. The higher the temperature, the faster the substitution reaction of fluorine for chlorine on silicon; however, excessively high temperatures can cause the volatilization of organofluorine compounds. Under the catalytic action of a catalyst, the preferred temperature is 50~80℃. Increasing the reactor pressure, on the one hand, promotes the solubility of hydrogen chloride gas in chlorosilanes and increases the gas-liquid residence time; on the other hand, increasing the pressure raises the boiling point of the organic matter, inhibiting the volatilization of organofluorine compounds in hydrogen chloride. Considering the economic efficiency of the reactor, the preferred reactor pressure is 0.5~2MPa.

[0039] In one or more preferred embodiments, the chlorosilane is a trichlorosilane or / and dichlorosilane with a molecular weight greater than 150, having the general formula R n SiCl （4-n） In the defluorinating agent composition, n is 1 or 2, and R is pentyl, phenyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylpentyl, dimethylbenzene, trimethylbenzene, or diethylbenzene. The catalyst is a tertiary amine alkane with a molecular weight higher than 150, having the general formula R`3N, where R` is phenyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, benzyl, phenethyl, phenylpropyl, phenylbutyl, or phenylpentyl. The amount of catalyst added to the defluorinating agent composition is 1‰ to 5% of the mass of the defluorinating agent composition, more preferably 0.5% to 2%.

[0040] In one or more preferred embodiments, the static mixer 5 is a cylindrical structure, with one or more perforated plates 12 disposed inside the cylindrical structure, more preferably 3-9. The perforated plates 12 are plates with uniformly distributed perforations, and their shape is adapted to the interior of the static mixer 5. The purpose of the perforated plates 12 is to ensure thorough mixing of the hydrogen chloride tail gas and the defluorinating agent composition. The perforated plates 12 can be arranged radially along the cylinder or at a certain angle to the radial direction. To achieve a good mixing effect, the static mixer 5 can be an elongated structure, which increases the contact time of the mixed gases, thereby increasing the mixing effect and reaction efficiency. More preferably, the length-to-diameter ratio of the static mixer 5 is 100:1 to 10.

[0041] According to the present invention, the hydrogen chloride gas inlet 10 is connected to the gas-liquid separator 3, and a one-way gas valve can be provided to control the flow direction and flow rate of the hydrogen chloride gas. In one or more preferred embodiments, a one-way gas valve 11 is provided between the hydrogen chloride gas inlet 10 and the gas-liquid separator 3.

[0042] According to the present invention, the Venturi nozzle 8 is a highly effective mixing component. To prevent the jet airflow from the Venturi nozzle 8 from impacting the static mixer 5 and to achieve a better mixing effect, a buffer area is provided at the outlet of the Venturi nozzle 8. In one or more preferred embodiments, a buffer zone 6 is further provided between the static mixer 5 and the Venturi nozzle 8.

[0043] According to the present invention, the device for continuous defluorination of industrial hydrogen chloride tail gas can be a column reactor structure. The column reactor is in three sections: a buffer section, a mixing section, and a separation section. The buffer section is 6, the static mixer 5 and the Venturi nozzle 8 are the mixing section, and the gas-liquid separator 3 and the condenser 2 are the separation section.

[0044] According to the present invention, the defluorination reaction can be carried out at a certain temperature and pressure, and the device for continuous defluorination of industrial hydrogen chloride tail gas can be equipped with a heating element. In one or more preferred embodiments, at least one of the buffer zone 6, static mixer 5, venturi nozzle 8 and gas-liquid separator 3 is equipped with a heating device for heating the defluorination reaction.

[0045] The device for continuous defluorination of industrial hydrogen chloride tail gas can be a closed pressure device that can adapt to high-pressure reactions.

[0046] According to the present invention, a preferred embodiment of a method for continuous defluorination of industrial hydrogen chloride tail gas includes the following steps:

[0047] A defluorinating agent composition is added to the device for continuous defluorination of industrial hydrogen chloride tail gas beforehand. The circulation pump 7 is started, and the device is heated to the preset temperature after the liquid forms a circulation loop. Industrial hydrogen chloride tail gas is then introduced into the device through the hydrogen chloride gas inlet 10. The gas enters the buffer zone 6 through the gas circulation loop 9 and the Venturi nozzle 8. The defluorinating agent composition enters the buffer zone 6 through the liquid circulation loop 4, the circulation pump 7, and the Venturi nozzle 8. The hydrogen chloride tail gas and the defluorinating agent composition are mixed in the buffer zone 6 and then enter the static mixer 5 simultaneously. Then they enter the gas-liquid separation device 3. The separated hydrogen chloride gas is condensed by the condenser 2 and discharged from the hydrogen chloride outlet 1.

[0048] Unless otherwise described in this invention, all provisions are based on existing techniques in the field.

[0049] The present invention will be further described below with reference to specific implementation examples, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternative solutions, improvements, and equivalent solutions that may be included within the scope of the claims.

[0050] Example 1

[0051] A method for continuous defluorination of industrial hydrogen chloride tail gas includes using an apparatus for continuous defluorination of industrial hydrogen chloride tail gas and a defluorinating agent composition; placing the defluorinating agent composition in the apparatus for continuous defluorination of industrial hydrogen chloride tail gas to carry out a continuous defluorination reaction;

[0052] like Figure 1 , Figure 2As shown, the device for continuous defluorination of industrial hydrogen chloride tail gas includes a static mixer 5. One end of the static mixer 5 is sequentially connected to a gas-liquid separator 3, a condenser 2, and a hydrogen chloride gas outlet 1. The other end of the static mixer 5 is connected to a Venturi nozzle 8. The gas-liquid separator 3 is connected to a liquid circulation loop 4 and a gas circulation loop 9. The gas circulation loop 9 is provided with a hydrogen chloride gas inlet 10 and is connected to the Venturi nozzle 8. The liquid circulation loop 4 is connected to the Venturi nozzle 8 through a circulation pump 7. A buffer zone 6 is also provided between the static mixer 5 and the Venturi nozzle 8. At least one of the buffer zone 6, the static mixer 5, the Venturi nozzle 8, and the gas-liquid separator 3 is equipped with a heating device.

[0053] A defluorinating agent composition is added to the device for continuous defluorination of industrial hydrogen chloride tail gas beforehand. The circulation pump 7 is started, and the device is heated to the preset temperature after the liquid forms a circulation loop. Industrial hydrogen chloride tail gas is then introduced into the device through the hydrogen chloride gas inlet 10. The gas enters the buffer zone 6 through the gas circulation loop 9 and the Venturi nozzle 8. The defluorinating agent composition enters the buffer zone 6 through the liquid circulation loop 4, the circulation pump 7, and the Venturi nozzle 8. The hydrogen chloride tail gas and the defluorinating agent composition are mixed in the buffer zone 6 and then enter the static mixer 5 simultaneously. Then they enter the gas-liquid separation device 3. The separated hydrogen chloride gas is condensed by the condenser 2 and discharged from the hydrogen chloride outlet 1.

[0054] In this embodiment, the static mixer 5 is a cylindrical structure with a length-to-diameter ratio of 100:5, and five circular perforated plates 12 are arranged radially inside the cylindrical structure. The fluorinating agent composition is decyltrichlorosilane and tridecyl tertiary amine.

[0055] The device in this embodiment is a column reactor structure, which is a closed pressure device. The column reactor is divided into three sections: a buffer section, a mixing section, and a separation section. The buffer section is the buffer section, the static mixer 5 and the Venturi nozzle 8 are the mixing section, and the gas-liquid separator 3 and the condenser 2 are the separation section.

[0056] In this embodiment, the method for continuous defluorination of industrial hydrogen chloride tail gas includes the following specific steps:

[0057] (1) 25L of decyltrichlorosilane and 500g of tridecyl tertiary amine were added to the reactor as a defluorination agent composition;

[0058] (2) Start the circulation pump 7, and the liquid begins to circulate in the reactor to preheat the reactor;

[0059] (3) When the temperature rises to 70℃, start introducing industrial hydrogen chloride tail gas from hydrogen chloride gas inlet 10, and control the hydrogen chloride gas inlet speed to 30g / min;

[0060] (4) When the pressure inside the reactor reaches 1 MPa, open hydrogen chloride gas outlet 1 to control the pressure inside the reactor to 1 MPa;

[0061] (5) Work continuously for 500 hours, and take samples for testing every hour.

[0062] A sample was taken after 5 minutes of continuous operation and analyzed by a fluoride ion electrode. The results showed that the hydrogen fluoride content in the inlet gas was 153 ppm and the hydrogen fluoride content in the outlet gas was 1.3 ppm; the defluorination efficiency was 99.15%.

[0063] Compared to traditional loop reactors, this invention, by setting up a static mixer 5, can greatly promote the mixing reaction of the gas and liquid phases inside the reactor, prolong the residence time of the gas and liquid phases, and improve the defluorination efficiency.

[0064] Example 2

[0065] As described in Example 1, the difference is that the chloroalkane in the defluorinating agent composition is replaced with phenyltrichlorosilane, and the catalyst is replaced with triphenyl tertiary amine, including the following steps:

[0066] (1) Add 25L of phenyltrichlorosilane and 500g of triphenyl tertiary amine as defluorinating agents into the reactor;

[0067] (2) Start the circulation pump 7, and the liquid begins to circulate in the reactor to preheat the reactor;

[0068] (3) When the temperature rises to 70℃, start introducing industrial hydrogen chloride tail gas from hydrogen chloride gas inlet 10, and control the hydrogen chloride gas inlet speed to 30g / min;

[0069] (4) When the pressure inside the reactor reaches 1 MPa, open hydrogen chloride gas outlet 1 to control the pressure inside the reactor to 1 MPa;

[0070] (5) Work continuously for 500 hours, and take samples for testing every hour.

[0071] A sample was taken after 5 minutes of continuous operation and analyzed by a fluoride ion electrode. The results showed that the hydrogen fluoride content in the inlet gas was 184 ppm and the hydrogen fluoride content in the outlet gas was 2.1 ppm; the defluorination efficiency was greater than 98.86%.

[0072] Example 3

[0073] As described in Example 1, the difference is:

[0074] A gas check valve 11 is provided between the hydrogen chloride gas inlet 10 and the gas-liquid separator 3. In this embodiment, the static mixer 5 is a cylindrical structure with a length-to-diameter ratio of 100:1, and nine circular perforated plates 12 are arranged radially inside the cylindrical structure.

[0075] Example 4

[0076] As described in Example 1, the difference is:

[0077] In this embodiment, the static mixer 5 is a cylindrical structure with a length-to-diameter ratio of 100:10. The cylindrical structure has three circular perforated plates 12 inside, and the circular perforated plates 12 are at a 45° angle to the radial direction.

[0078] Examples 5-11

[0079] As described in Example 1, the defluorinating agent composition, temperature, and pressure were adjusted as shown in Table 1.

[0080] Table 1

[0081]

[0082] Comparative Example 1

[0083] In this comparative example, the reactor is a conventional loop reactor. No static mixer is installed in the main reactor. The main reaction zone volume is 25 liters. The operating procedure is as follows:

[0084] (1) 25L of decyltrichlorosilane was added to the reactor as a defluorinating agent;

[0085] (2) Start the circulation pump, and the liquid begins to circulate in the reactor to preheat the reactor;

[0086] (3) When the temperature rises to 70℃, industrial hydrogen chloride tail gas is introduced from the hydrogen chloride gas inlet, and the hydrogen chloride gas inlet speed is controlled to be 30g / min.

[0087] (4) When the pressure inside the reactor reaches 1 MPa, open the hydrogen chloride gas outlet and control the pressure inside the reactor to 1 MPa;

[0088] (5) Work continuously for 500 hours, and take samples for testing every hour.

[0089] A sample taken after 5 minutes of continuous operation was analyzed by a fluoride ion electrode. The results showed that the hydrogen fluoride content in the inlet gas was 147 ppm and the hydrogen fluoride content in the outlet gas was 15.2 ppm; the defluorination efficiency was 91.02%.

[0090] Comparative Example 2

[0091] In this comparative example, the reactor is a continuous stirred tank reactor with a main reaction zone volume of 25 liters. The operating procedure is as follows:

[0092] (1) 25L of decyltrichlorosilane was added to the reactor as a defluorinating agent;

[0093] (2) Start stirring and preheat the reactor;

[0094] (3) When the temperature rises to 70°C, start introducing industrial hydrogen chloride tail gas from the bottom of the reactor and control the hydrogen chloride intake rate to 30 g / min.

[0095] (4) When the pressure inside the reactor reaches 1 MPa, open the hydrogen chloride gas outlet at the top of the reactor and control the pressure inside the reactor to 1 MPa;

[0096] (5) Work continuously for 500 hours, and take samples for testing every hour.

[0097] A sample was taken after 5 minutes of continuous operation and analyzed by a fluoride ion electrode. The results showed that the hydrogen fluoride content in the inlet gas was 151 ppm and the hydrogen fluoride content in the outlet gas was 61.3 ppm; the defluorination efficiency was 59.40%.

Claims

1. A method for continuous defluorination of hydrogen fluoride from industrial hydrogen chloride tail gas, characterized in that, The invention includes an apparatus for continuous defluorination of hydrogen fluoride from industrial hydrogen chloride tail gas and a defluorinating agent composition, wherein the defluorinating agent composition is placed in the apparatus for continuous defluorination of hydrogen fluoride from industrial hydrogen chloride tail gas to carry out a continuous defluorination reaction. The device for continuous defluorination of industrial hydrogen chloride tail gas includes a static mixer (5). One end of the static mixer (5) is sequentially connected to a gas-liquid separator (3), a condenser (2), and a hydrogen chloride gas outlet (1). The other end of the static mixer (5) is connected to a Venturi nozzle (8). The gas-liquid separator (3) is connected to a liquid circulation loop (4) and a gas circulation loop (9). The gas circulation loop (9) is provided with a hydrogen chloride gas inlet (10) and is connected to the Venturi nozzle (8). The liquid circulation loop (4) is connected to the gas circulation loop (9) by a circulation pump. (7) Connected to the Venturi nozzle (8); a buffer zone (6) is also provided between the static mixer (5) and the Venturi nozzle (8), and at least one of the buffer zone (6), the static mixer (5), the Venturi nozzle (8) and the gas-liquid separation device (3) is provided with a heating device; the static mixer (5) is a cylindrical structure, and one or more orifice plates (12) are provided inside the cylindrical structure; the length-to-diameter ratio of the static mixer (5) is 100:1~10, and a gas check valve (11) is provided between the hydrogen chloride gas inlet (10) and the gas-liquid separation device (3); The defluorinating agent composition comprises a chlorosilane with a molecular weight greater than 150 and a catalyst, wherein the catalyst is a tertiary amine alkane with a molecular weight greater than 150.

2. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The defluorination temperature is 10~100℃.

3. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 2, characterized in that, The defluorination temperature is 50~80℃.

4. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The defluorination pressure is 0.1~5MPa.

5. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 4, characterized in that, The defluorination pressure is 0.5~2MPa.

6. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The chlorosilane is a trichlorosilane or / and dichlorosilane with a molecular weight higher than 150, having the general formula R n SiCl （4-n） n is 1 or 2, and R is pentyl, phenyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylpentyl, dimethylbenzene, trimethylbenzene, or diethylbenzene.

7. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The catalyst is a tertiary amine alkane with a molecular weight higher than 150, having the general formula R`3N, where R` is phenyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, benzyl, phenethyl, phenylpropyl, phenylbutyl, or phenylpentyl.

8. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The amount of catalyst added to the defluorinating agent composition is 1‰ to 5% of the mass of the defluorinating agent composition.

9. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 8, characterized in that, The amount of catalyst added to the defluorinating agent composition is 0.5% to 2% of the mass of the defluorinating agent composition.

10. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The number of orifice plates (12) is 3-9.

11. The method for continuous defluorination of industrial hydrogen chloride tail gas according to claim 1, characterized in that, The perforated plate (12) is set radially along the cylinder or at an angle to the radial direction.

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