Intermittent production method and system for preparing electronic-grade hydrogen chloride by using hydrogen chloride gas by-product of chloroethylene

Abstract

The present application provides a batch production method and system for preparing electronic-grade hydrogen chloride by using hydrogen chloride gas by-produced from chlorinated ethylene, and relates to the field of electronic-grade hydrogen chloride preparation. The batch production method for preparing electronic-grade hydrogen chloride by using hydrogen chloride gas by-produced from chlorinated ethylene comprises sequentially performed de-ethylene treatment, de-watering treatment, de-carbon treatment, de-impurity treatment and de-dust treatment. The batch production method and system can effectively adapt to the fluctuation of impurity content in hydrogen chloride gas by-produced from chlorinated ethylene, and has strong process adaptability. The residual chlorinated organic impurities in hydrogen chloride gas by-produced from chlorinated ethylene can be effectively removed, the purity and impurity content of the prepared hydrogen chloride product meet the quality requirements of electronic-grade hydrogen chloride, the quality of the prepared hydrogen chloride product is stable, and the large-scale industrial processing requirements can be met.

Description

Technical Field

[0001] This invention relates to the field of electronic-grade hydrogen chloride preparation, and in particular to an intermittent production method and system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production. Background Technology

[0002] Hydrogen chloride gas is produced as a byproduct during the production of chloroethylene. Specifically, it is produced by the thermal cracking reaction of tetrachloroethane under chlorine catalysis to generate a mixed tail gas. After cooling and separation to remove most of the chlorine-containing organic compounds (such as 1,1,2,2-tetrachloroethane, trichloroethylene, 1,1,2-trichloroethane, and tetrachloroethylene), the byproduct hydrogen chloride gas is collected.

[0003] The impurities in hydrogen chloride gas, a byproduct of vinyl chloride production, are complex. Even after the aforementioned cooling and separation process, it still contains a certain amount of chlorinated organic impurities, as well as carbon dioxide, carbon monoxide, nitrogen, oxygen, hydrogen, methane, chlorine, water, and oils. Conventional electronic-grade hydrogen chloride preparation processes are insufficient for targeted purification and impurity removal. Furthermore, due to fluctuations in raw materials and process conditions during vinyl chloride production, the impurity content in each batch of byproduct hydrogen chloride gas varies significantly. Existing electronic-grade hydrogen chloride preparation processes cannot adapt to these variations in impurity content, resulting in poor process adaptability.

[0004] Meanwhile, conventional treatment processes cannot effectively remove the chlorine-containing organic impurities remaining in the hydrogen chloride gas produced as a byproduct of vinyl chloride production. The purity and impurity content of the resulting hydrogen chloride product cannot meet the quality requirements for electronic-grade hydrogen chloride. Furthermore, the quality of the resulting hydrogen chloride product is unstable and cannot meet the requirements for large-scale industrial processing.

[0005] Based on this, a batch production method and system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, is provided. This method can effectively adapt to fluctuations in the impurity content of the hydrogen chloride gas, exhibiting strong process adaptability. It can effectively remove residual chlorine-containing organic impurities from the hydrogen chloride gas, and the purity and impurity content of the obtained hydrogen chloride product meet the quality requirements for electronic-grade hydrogen chloride. Furthermore, the quality of the obtained hydrogen chloride product is stable, meeting the requirements for large-scale industrial processing, and thus possesses significant technical significance and research value. Summary of the Invention

[0006] To address the technical problems existing in the prior art, this invention provides an intermittent production method and system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production. This method effectively adapts to fluctuations in the impurity content of the hydrogen chloride gas, exhibiting strong process adaptability. It effectively removes residual chlorine-containing organic impurities from the hydrogen chloride gas, ensuring that the purity and impurity content of the obtained hydrogen chloride product meet the quality requirements for electronic-grade hydrogen chloride. Furthermore, the quality of the obtained hydrogen chloride product is stable, meeting the requirements for large-scale industrial processing.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] An intermittent production method for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production, consists of sequential processes including deolefin removal, dehydration, decarbonization, impurity removal, and dust removal.

[0009] The deolefin treatment method is as follows: hydrogen chloride gas, a by-product of ethylene chloride, is condensed and liquefied, then fed into a deolefin removal tower. High-boiling-point substances are removed by distillation, and the light components at the top of the tower are collected and condensed to obtain deolefin removal condensate.

[0010] The dehydration treatment method is as follows: after the deolefin condensate is heated and vaporized, it is fed into a dehydration tower filled with water-absorbing packing. After contacting the water-absorbing packing for dehydration, it is condensed to obtain dehydrated condensate.

[0011] The decarbonization process involves feeding the dehydrated condensate into a decarbonization tower, heating and vaporizing it to remove light component impurities, and then condensing it to obtain the decarbonization treatment liquid.

[0012] The method for removing impurities is as follows: after the decarbonization liquid is heated and vaporized, it is fed into a deimaging tower filled with silicon-aluminum molecular sieves. After contacting the silicon-aluminum molecular sieves to remove impurity components, it is filtered and fed into a dust removal tower.

[0013] The dust removal process involves a dust removal tower receiving hydrogen chloride gas from a purification tower to remove solid dust and residual high-boiling substances, thereby obtaining electronic-grade hydrogen chloride.

[0014] Furthermore, the deolefin removal method involves condensing and liquefying hydrogen chloride gas, a byproduct of ethylene chloride production, to obtain crude hydrogen chloride solution. The crude hydrogen chloride solution is fed into the deolefin removal tower, maintaining the bottom liquid level at 60-90%. The top pressure of the deolefin removal tower is controlled at 1.6-2.2 MPa, and the bottom temperature is controlled at -8°C to -4°C for deolefin removal. During the deolefin removal process, the light components at the top of the tower are condensed to obtain deolefin removal condensate. A portion of the deolefin removal condensate is refluxed back to the deolefin removal tower.

[0015] Preferably, the reflux ratio of the deolefin condensate is controlled to be 1-1.2:1;

[0016] The flow rate of the deolefin condensate returned to the deolefin tower is 80-200 kg / h.

[0017] Preferably, in the dehydration process, the working pressure of the dehydration tower is controlled at 3.6-4.2 MPa;

[0018] The absorbent filler is composed of anhydrous calcium chloride spikes and 3A molecular sieves;

[0019] Preferably, the weight ratio of anhydrous calcium chloride spikes to 3A molecular sieve is 7-7.5:2.5-3.

[0020] Furthermore, the decarbonization treatment method is as follows: the dehydration condensate is fed into the decarbonization tower, the pressure at the top of the decarbonization tower is controlled at 4.2-4.8 MPa, the dehydration condensate is heated and vaporized into hydrogen chloride gas, and then condensed by the decarbonization condenser. The condensate from the decarbonization condenser is completely refluxed back to the decarbonization tower; the uncondensed gas from the decarbonization condenser is condensed by the recovery condenser, the condensate from the recovery condenser is collected to obtain liquid hydrogen chloride, and the uncondensed gas from the recovery condenser is used to prepare hydrochloric acid; the condensate from the decarbonization condenser is completely refluxed until the content of light component impurities meets the predetermined requirements, the material in the decarbonization tower is completely evaporated, and the decarbonization treatment liquid is obtained by condensation and recovery.

[0021] Preferably, in the decarbonization process, the flow rate of the condensate in the decarbonization condenser during total reflux is 500-900 kg / h; the flow rate of the uncondensed gas in the decarbonization condenser is 20-60 kg / h.

[0022] The condensate from the decarbonization condenser is fully refluxed until the light component impurities meet the following requirements: hydrogen content < 0.1 ppm, nitrogen content < 5 ppm, total oxygen and argon content < 5 ppm, total hydrocarbon content < 1 ppm, carbon monoxide content < 15 ppm, and carbon dioxide content < 80 ppm.

[0023] Preferably, in the impurity removal process, the silica-alumina molecular sieve is composed of 13X molecular sieve and 3A molecular sieve; the weight ratio of 13X molecular sieve to 3A molecular sieve is 3-3.5:1.

[0024] Furthermore, the dust removal process involves the following steps: the dust removal tower receives hydrogen chloride gas from the impurity removal tower, the pressure at the top of the dust removal tower is controlled at 3.6-4.2 MPa, and the temperature at the bottom of the tower is controlled at 14-22°C. After the light components at the top of the dust removal tower are condensed, the condensate is completely returned to the dust removal tower until the condensate meets the specifications for electronic-grade hydrogen chloride. The condensate is then collected to obtain electronic-grade hydrogen chloride.

[0025] The production system for implementing the aforementioned method consists of a deolefin removal unit, a dehydration unit, a decarbonization unit, a purification unit, and a dust removal unit connected in sequence.

[0026] The deolefin removal unit includes: a pre-condenser, a crude product tank, a deolefin removal tower, a deolefin removal condenser, a deolefin removal reflux tank, and a recovery vessel;

[0027] The dehydration unit includes: a deolefin transfer tank, a dehydration tower, a dehydration condenser, and a dehydration water transfer tank;

[0028] The decarbonization unit includes: a decarbonization tower, a decarbonization condenser, a recovery condenser, a recovery buffer tank, a 3N-grade buffer tank, and a chemical-grade buffer tank;

[0029] The impurity removal unit includes: an impurity removal transfer tank and an impurity removal tower;

[0030] The dust removal unit includes: a dust removal tower, a dust removal condenser, a dust removal reflux tank, and an electronic-grade buffer tank.

[0031] Furthermore, in the decarbonization unit, the top outlet of the decarbonization tower is connected to the inlet of the decarbonization condenser, and the liquid outlet of the decarbonization condenser is connected to the top reflux outlet of the decarbonization tower; the uncondensed gas outlet of the decarbonization condenser is connected to the inlet of the recovery condenser; the liquid outlet of the recovery condenser is connected to the inlet of the recovery buffer tank; and the uncondensed gas outlet of the recovery condenser is connected to the hydrochloric acid preparation section.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The batch production method and system of the present invention for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a by-product of ethylene chloride, can effectively remove residual chlorine-containing organic matter and other impurities in the hydrogen chloride gas by-product of ethylene chloride by sequentially performing de-olefin treatment, dehydration treatment, decarbonization treatment, impurity removal treatment and dust removal treatment, thereby significantly reducing the content of gaseous impurities. The purity and impurity content of the hydrogen chloride product obtained meet the quality requirements of electronic-grade hydrogen chloride. It can reduce the gaseous impurities of hydrogen chloride to 0.7 ppm and below, and the moisture content to 80 ppb and below. At the same time, it can effectively adapt to the fluctuation of impurity content in the hydrogen chloride gas by-product of ethylene chloride, with strong process adaptability and stable quality of the hydrogen chloride product obtained, which can meet the requirements of large-scale industrial processing.

[0034] (2) The batch production method and system of the present invention for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, adopts a batch production process throughout and has sufficient margin to overcome the problem of large variations in the impurity content in the raw material gas, thus exhibiting strong adaptability to changes in the impurity content of the raw material gas. Experiments have shown that, for hydrogen chloride gas from ethylene chloride with different impurity contents, the obtained electronic-grade hydrogen chloride can achieve a hydrogen chloride content of 99.999928-99.999934 wt% and a hydrogen content of 0.0 wt%. The concentrations of hydrogen chloride were 1-0.02 ppm, nitrogen 0.01 ppm, oxygen and argon 0.01 ppm, total methane and acetylene 0.1 ppm, carbon monoxide 0.08-0.09 ppm, carbon dioxide 0.41-0.45 ppm, and moisture 0.05-0.06 ppm. 1,1,2,2-Tetrachloroethane and trichloroethylene were not detected. The purity of hydrogen chloride exceeded the requirements (≥99.999 wt% and ≥99.9995 wt%) specified in the current national standard GB / T 14602-2014 "Hydrogen Chloride for Electronic Industry".

[0035] (3) The batch production method and system of the present invention for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a by-product of ethylene chloride, has a strong effect on removing chlorinated organic impurities from the hydrogen chloride gas, a by-product of ethylene chloride: low-temperature batch distillation is adopted in the de-ene treatment, which can reduce the content of high-boiling substances in hydrogen chloride to 0.5 ppm or below, and high-boiling substances such as trichloroethylene and tetrachloroethylene are recovered by periodically collecting heavy components in the bottom of the column, thereby reducing the production loss of trichloroethylene and tetrachloroethylene.

[0036] (4) The batch production method and system of the present invention for preparing electronic-grade hydrogen chloride using hydrogen chloride gas as a byproduct of chloroethylene has an average yield of 74.9-75.3% for electronic-grade hydrogen chloride, a yield of 20.0-20.3% for liquid hydrogen chloride with a purity of 99.9 wt% produced as a byproduct of the decarbonization step, and a total yield of 95.0-95.6%.

[0037] (5) The batch production method and system of the present invention for preparing electronic-grade hydrogen chloride using hydrogen chloride gas by-product of chloroethylene has high purity and stable product quality: through decarbonization and deimpurification, light component impurities can be removed by batch distillation and adsorption respectively. Compared with the existing continuous production process, it is easier to achieve segmented quality control and the product quality is more stable. Attached Figure Description

[0038] Figure 1This is a schematic diagram of the batch production system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production, according to the present invention. In the diagram, 1-pre-condenser; 2-crude product tank; 3-de-olefin tower; 4-de-olefin condenser; 5-de-olefin reflux tank; 6-recovery vessel; 7-de-olefin transfer tank; 8-dehydration tower; 9-dehydration condenser; 10-dehydration transfer tank; 11-decarbonization tower; 12-decarbonization condenser; 13-recovery condenser; 14-recovery buffer tank; 15-3N-grade buffer tank; 16-chemical-grade buffer tank; 17-purification transfer tank; 18-purification tower; 19-dust removal tower; 20-dust removal condenser; 21-dust removal reflux tank; 22-electronic-grade buffer tank. Detailed Implementation

[0039] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, "first," "second," etc., are used to distinguish similar objects and are not used to describe a particular order or sequence. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] This invention provides an intermittent production method for electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, comprising sequentially performed deolefin removal, dehydration, decarbonization, impurity removal, and dust removal processes.

[0042] The deolefin removal process involves pressurizing hydrogen chloride gas, a byproduct of ethylene chloride production, to 3-5 MPa using a diaphragm compressor. This gas is then introduced into a pre-condenser 1, where it liquefies after heat exchange with 0°C brine, yielding crude hydrogen chloride solution, which is temporarily stored in a crude product tank 2. The crude hydrogen chloride solution in tank 2 is intermittently replenished to the deolefin removal tower 3 to maintain a bottom level of 60-90%. The top pressure of the deolefin removal tower 3 is controlled at 1.6-2.2 MPa, and the bottom temperature is maintained at -8°C to -4°C. Each replenishment of the crude hydrogen chloride solution is 9-11% of the bottom level of the deolefin removal tower 3. This process removes high-boiling-point impurities such as 1,1,2,2-tetrachloroethane, trichloroethylene, chlorine, and grease from the crude hydrogen chloride solution, leaving them in the bottom of the deolefin removal tower 3.

[0043] During the deolefin removal process, the light components at the top of the tower enter the deolefin removal condenser 4 for condensation, and the deolefin removal condensate enters the deolefin removal reflux tank 5. The reflux ratio is controlled at 1-1.2:1, and a portion of the deolefin removal condensate in the deolefin removal reflux tank 5 is refluxed back to the deolefin removal tower 3 through the top of the tower. The reflux flow rate at the top of the tower is 80-200 kg / h.

[0044] During the deolefin removal process, based on the liquid level in the deolefin removal reflux tank 5, the deolefin removal condensate in the deolefin removal reflux tank 5 is intermittently drawn into the deolefin removal transfer tank 7 for temporary storage, pending further processing. The amount drawn each time is controlled to be 48-52% of the liquid level in the deolefin removal reflux tank 5, and the static pressure difference between the two devices caused by the height difference is balanced during the drawing process using gas pressure. In addition, the heavy components in the bottom of the tower are periodically discharged into the recovery tank 6 for collection.

[0045] The deolefin removal process in this embodiment of the invention consists of a deolefin removal tower 3, a deolefin removal condenser 4, and a deolefin removal reflux tank 5 forming a distillation circulation loop, which is used to remove olefins from the crude hydrogen chloride solution. After deolefin removal by distillation in the deolefin removal tower 3, high-boiling-point impurities such as 1,1,2,2-tetrachloroethane, trichloroethylene, chlorine, and grease remain in the bottom of the deolefin removal tower 3. The total high-boiling-point content of the hydrogen chloride liquid (i.e., the deolefin removal condensate) after removing high-boiling-point impurities is <0.5ppm, and it enters the deolefin removal reflux tank 5.

[0046] The dehydration process is as follows: the deolefin condensate in the deolefin transfer tank 7 is heated by its jacket hot water and vaporized into hydrogen chloride gas. The hydrogen chloride gas enters the dehydration tower 8, which is filled with water-absorbing packing. The working pressure of the dehydration tower 8 is controlled at 3.6-4.2 MPa for dehydration treatment. After filtration through a filter with a filtration accuracy of 0.01 μm, the condensate enters the dehydration condenser 9 and liquefies into dehydration condensate after heat exchange with 0℃ brine. The dehydration condensate enters the dehydration transfer tank 10 for temporary storage. When the cumulative liquid level in the dehydration transfer tank 10 reaches 92-95%, the dehydration condensate in the dehydration transfer tank 10 is completely introduced into the decarbonization tower 11 for subsequent treatment. During the transportation process, the static pressure difference generated by the height difference between the two devices is used to balance the gas pressure.

[0047] In the dehydration process, the absorbent packing material is composed of anhydrous calcium chloride spiked balls and 3A molecular sieves; the weight ratio of anhydrous calcium chloride spiked balls to 3A molecular sieves is 7-7.5:2.5-3.

[0048] In the dehydration process of this embodiment of the invention, hydrogen chloride gas comes into contact with the water-absorbing packing material packed in the dehydration tower 8. The hydrogen chloride gas is adsorbed and dehydrated by the combination of anhydrous calcium chloride spikes and 3A molecular sieve. After the dehydration process is completed, the dehydrated hydrogen chloride gas (moisture content <1ppm) flows out of the dehydration tower 8, is filtered, and collected in the dehydration transfer tank 10.

[0049] The decarbonization process is as follows: Decarbonization tower 11 receives dehydration condensate from dehydration transfer tank 10, and the pressure at the top of decarbonization tower 11 is controlled at 4.2-4.8 MPa. The dehydration condensate is heated by hot water in the bottom of decarbonization tower 11 and vaporized into hydrogen chloride gas. The hydrogen chloride gas flows from the bottom of decarbonization tower 11 to the top, enters decarbonization condenser 12, exchanges heat with 0℃ brine, and liquefies into decarbonization condensate. The decarbonization condensate is then completely refluxed (reflux flow rate is 500-900 kJ / L). The gas is fed to the top of the decarbonization tower 11 at a flow rate of 20-60 kg / h. During the condensation process, a small amount of uncondensed gas (flow rate of 20-60 kg / h) is discharged from the tail end of the decarbonization condenser 12 to the recovery condenser 13 for further condensation. About 90% of the tail gas in the recovery condenser 13 is condensed and recovered into liquid hydrogen chloride with a purity of 99.9 wt%. After passing through the recovery buffer tank 14, it is temporarily stored in the 3N-level buffer tank 15. The uncondensed gas (about 10%) in the recovery condenser 13 is collected and used to prepare hydrochloric acid.

[0050] In this embodiment of the invention, the decarbonization process is carried out using a decarbonization tower 11. The purpose is to remove low-boiling-point impurities from the material. The decarbonization process is carried out until the content of light component impurities in the material in the decarbonization tower 11 meets the following requirements: hydrogen < 0.1 ppm, nitrogen < 5 ppm, oxygen + argon < 5 ppm, total hydrocarbons (calculated as methane) < 1 ppm, carbon monoxide < 15 ppm, and carbon dioxide < 80 ppm. At this point, the material in the decarbonization tower 11 is completely evaporated and condensed by the decarbonization condenser 12 to obtain a decarbonization treatment liquid. This liquid is then introduced into a chemical-grade buffer tank 16 for temporary storage, pending further processing.

[0051] The method for removing impurities is as follows: the decarbonization liquid in the chemical-grade buffer tank 16 is transferred to the impurity removal transfer tank 17. During the transportation process, the static pressure difference generated by the height difference between the two devices is used to balance the gas pressure. The decarbonization liquid in the impurity removal transfer tank 17 is heated by hot water and vaporized into hydrogen chloride gas. The hydrogen chloride gas flows through the impurity removal tower 18 filled with silicon-aluminum molecular sieves for impurity removal. After filtration, it is fed from the bottom to the dust removal tower 19 for subsequent processing.

[0052] In the impurity removal process, the silica-alumina molecular sieve is composed of 13X molecular sieve and 3A molecular sieve, with a weight ratio of 3-3.5:1. The regeneration heat source after the silica-alumina molecular sieve reaches adsorption equilibrium is superheated steam, the regeneration temperature is 150-200℃, and the regeneration time is 4-8 hours.

[0053] The impurity removal process in this embodiment of the invention uses a silica-alumina molecular sieve packed in the impurity removal tower 18 to selectively adsorb and remove impurities such as nitrogen, oxygen (argon), carbon monoxide, carbon dioxide, and methane from hydrogen chloride gas, thereby controlling the impurities in hydrogen chloride at a predetermined level.

[0054] The dust removal process is as follows: Dust removal tower 19 receives hydrogen chloride gas from impurity removal tower 18. The hydrogen chloride gas flows upward from the bottom of dust removal tower 19, enters dust removal condenser 20, and liquefies after heat exchange with 0℃ brine. The liquid hydrogen chloride is then returned to dust removal tower 19 via dust removal reflux tank 21. The pressure at the top of dust removal tower 19 is controlled at 3.6-4.2 MPa, the reflux flow rate is 300-600 kg / h, and the bottom temperature is 14-22℃ for dust removal treatment. The dust is then analyzed by online gas chromatography. The PDHID and FID detectors detect that the content of the material in the dust removal return tank 21 meets the following requirements: hydrogen chloride ≥ 99.9999 wt%, nitrogen < 0.5 ppm, oxygen + argon < 0.5 ppm, methane + acetylene < 0.1 ppm, carbon monoxide < 0.5 ppm, carbon dioxide < 0.5 ppm, moisture < 0.5 ppm, and total impurities ≤ 1 ppm. The material in the dust removal return tank 21 is then transported to the electronic grade buffer tank 22 to produce electronic grade hydrogen chloride.

[0055] In the dust removal process of this invention embodiment, the hydrogen chloride gas in the dust removal tower 19 exchanges matter and energy with the hydrogen chloride liquid flowing down from the top of the tower, leaving solid dust and high-boiling liquid at the bottom of the tower, thereby producing electronic-grade hydrogen chloride that meets the requirements.

[0056] The present invention will be further described below with reference to some specific embodiments.

[0057] Example 1

[0058] This embodiment uses hydrogen chloride gas, a byproduct of vinyl chloride production, as the feed gas. Its main component is hydrogen chloride, and it contains impurities such as 1,1,2,2-tetrachloroethane, trichloroethylene, 1,1,2-trichloroethane, tetrachloroethylene, carbon dioxide, carbon monoxide, nitrogen, oxygen, hydrogen, methane, chlorine, water, and grease. Specifically, the hydrogen chloride gas, a byproduct of vinyl chloride production, is the tail gas produced by the thermal cracking reaction of tetrachloroethane under chlorine catalysis. After cooling and separation to remove most of the chlorine-containing organic compounds (1,1,2,2-tetrachloroethane, trichloroethylene, 1,1,2-trichloroethane, tetrachloroethylene) from the tail gas, the feed gas is obtained. Testing revealed that the raw material gas used in this embodiment contained 99.6891 wt% hydrogen chloride, 59 ppm hydrogen, 329 ppm nitrogen, 218 ppm total oxygen and argon, 613 ppm carbon monoxide, 1289 ppm carbon dioxide, 2 ppm total methane and acetylene, 13 ppm moisture, 316 ppm 1,1,2,2-tetrachloroethane, 117 ppm trichloroethylene, 64 ppm 1,1,2-trichloroethane, and 89 ppm tetrachloroethylene.

[0059] This embodiment provides a batch production method for electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production. Specifically:

[0060] (1) Deolefin treatment

[0061] Hydrogen chloride gas, a byproduct of ethylene chloride production, is pressurized to 4 MPa by a diaphragm compressor and then introduced into pre-condenser 1. In pre-condenser 1, it liquefies after heat exchange with 0°C brine, yielding crude hydrogen chloride solution, which is temporarily stored in crude product tank 2. The crude hydrogen chloride solution in crude product tank 2 is intermittently replenished to the deolefin removal tower 3 to maintain the bottom liquid level at 75%. The top pressure of deolefin removal tower 3 is controlled at 1.9 MPa, and the bottom temperature is maintained at -7°C for deolefin removal treatment. During the deolefin removal process, the light components at the top of the tower enter the deolefin removal condenser 4 for condensation. The deolefin removal condensate then enters the deolefin removal reflux tank 5. The reflux ratio is controlled at 1:1. A portion of the deolefin removal condensate in the reflux tank 5 is refluxed back to the deolefin removal tower 3 via the top of the tower, with a top reflux flow rate of 130 kg / h. The crude hydrogen chloride liquid in crude product tank 2 is intermittently replenished to deolefin tower 3, and the amount of feed replenished each time is controlled to be 10% of the bottom liquid level of deolefin tower 3.

[0062] The deolefin removal reflux tank 5 receives the deolefin removal-treated hydrogen chloride liquid. Based on the liquid level in the deolefin removal reflux tank 5, the deolefin removal condensate is intermittently drawn from the tank and temporarily stored in the deolefin removal transfer tank 7 for further processing. The amount drawn out each time is controlled to be 50% of the liquid level in the deolefin removal reflux tank 5, and the static pressure difference between the two devices caused by the height difference is balanced during the drawing process using gas pressure. Furthermore, during the deolefin removal process, the heavy components in the bottom of the tower are periodically discharged into the recovery tank 6.

[0063] (2) Dehydration treatment

[0064] The deolefin condensate in the deolefin transfer tank 7 is heated by its jacket hot water and vaporized into hydrogen chloride gas. The hydrogen chloride gas enters the dehydration tower 8, which is filled with water-absorbing packing. The working pressure of the dehydration tower 8 is controlled at 3.9 MPa. After contacting the water-absorbing packing in the dehydration tower 8, the hydrogen chloride gas removes moisture. The dehydrated hydrogen chloride gas (moisture content <1 ppm) flows out of the dehydration tower 8, is filtered by a filter with a filtration accuracy of 0.01 μm, and enters the dehydration condenser 9. After exchanging heat with 0℃ brine, it is liquefied into dehydration condensate. The dehydration condensate enters the dehydration transfer tank 10 for temporary storage. When the cumulative liquid level in the dehydration transfer tank 10 reaches 95%, the dehydration condensate in the dehydration transfer tank 10 is completely introduced into the decarbonization tower 11 for subsequent processing. During the transportation process, the static pressure difference generated by the height difference between the two devices is used to balance the gas pressure.

[0065] The absorbent filler consists of anhydrous calcium chloride spiked balls and 3A molecular sieves; the weight ratio of anhydrous calcium chloride spiked balls to 3A molecular sieves is 7:3.

[0066] (3) Decarbonization treatment

[0067] The decarbonization tower 11 receives dehydration condensate from the dehydration transfer tank 10. The pressure at the top of the decarbonization tower 11 is controlled at 4.5 MPa. The dehydration condensate is heated by hot water in the bottom of the decarbonization tower 11 and vaporized into hydrogen chloride gas. The hydrogen chloride gas flows from the bottom of the decarbonization tower 11 to the top and enters the decarbonization condenser 12. After exchanging heat with 0℃ brine, it liquefies into decarbonization condensate. The decarbonization condensate is completely refluxed (reflux flow rate of 700 kg / h) to the top of the decarbonization tower 11. A small amount of uncondensed gas (flow rate of 40 kg / h) during the condensation process is discharged from the tail end of the decarbonization condenser 12 to the recovery condenser 13 for further condensation. About 90% of the tail gas in the recovery condenser 13 is condensed and recovered into liquid hydrogen chloride with a purity of 99.9 wt%. After passing through the recovery buffer tank 14, it is temporarily stored in the 3N-level buffer tank 15. The uncondensed gas (about 10%) in the recovery condenser 13 is collected and used to prepare hydrochloric acid. The decarbonization tower 11 performs decarbonization treatment to remove low-boiling-point impurities from the material. When the content of light component impurities in the material in the decarbonization tower 11 meets the following requirements: hydrogen < 0.1 ppm, nitrogen < 5 ppm, oxygen and argon < 5 ppm, total hydrocarbons (calculated as methane and acetylene) < 1 ppm, carbon monoxide < 15 ppm, and carbon dioxide < 80 ppm, the valves of the reflux pipeline between the decarbonization condenser 12 and the decarbonization tower 11 are closed, and the valves of the pipeline between the decarbonization condenser 12 and the recovery condenser 13 are closed. The valves of the pipeline between the decarbonization tower 11 and the chemical-grade buffer tank 16 are opened. The material in the decarbonization tower 11 is completely evaporated, and after being condensed by the decarbonization condenser 12, the decarbonization treatment liquid is obtained and introduced into the chemical-grade buffer tank 16 for temporary storage, pending subsequent processing.

[0068] (4) Impurity removal treatment

[0069] The decarbonization treatment liquid in the chemical grade buffer tank 16 is transferred to the impurity removal transfer tank 17. During the transportation process, the static pressure difference generated by the height difference between the two devices is used to balance the gas pressure. The decarbonization treatment liquid in the impurity removal transfer tank 17 is heated by hot water and vaporized into hydrogen chloride gas. The hydrogen chloride gas flows through the impurity removal tower 18 filled with silicon-aluminum molecular sieve. Impurities such as nitrogen, oxygen (argon), carbon monoxide, carbon dioxide, and methane in the hydrogen chloride gas are selectively adsorbed and removed. After filtration, it is fed from the bottom to the dust removal tower 19 for further treatment.

[0070] The silica-alumina molecular sieve is composed of 13X molecular sieve and 3A molecular sieve, with a weight ratio of 3.2:1. The regeneration heat source for the silica-alumina molecular sieve after reaching adsorption equilibrium is superheated steam, the regeneration temperature is 180℃, and the regeneration time is 6 hours.

[0071] (5) Dust removal treatment

[0072] Dust removal tower 19 receives hydrogen chloride gas from impurity removal tower 18. The hydrogen chloride gas flows upward from the bottom of dust removal tower 19, enters dust removal condenser 20, and liquefies after heat exchange with 0℃ brine. The liquid hydrogen chloride flows back to dust removal tower 19 via dust removal reflux tank 21. The pressure at the top of dust removal tower 19 is controlled at 3.8MPa, the reflux flow rate is 450kg / h, and the bottom temperature is 20℃. The hydrogen chloride gas in impurity removal tower 18 exchanges matter and energy with the liquid hydrogen chloride flowing down from the top of the tower, leaving solid dust and high-boiling liquid substances at the bottom of the tower. Linear analytical gas chromatography (PDHID and FID detectors) was used to detect the content of each component in the material in the dust removal reflux tank 21 to meet the following requirements: hydrogen chloride ≥ 99.9999 wt%, nitrogen < 0.5 ppm, oxygen + argon < 0.5 ppm, methane + acetylene < 0.1 ppm, carbon monoxide < 0.5 ppm, carbon dioxide < 0.5 ppm, moisture < 0.5 ppm, and total impurities ≤ 1 ppm. The material in the dust removal reflux tank 21 was then transferred to the electronic grade buffer tank 22 to obtain electronic grade hydrogen chloride.

[0073] Testing revealed that the electronic-grade hydrogen chloride prepared in this embodiment contained 99.999934 wt% hydrogen chloride, 0.02 ppm hydrogen, 0.01 ppm nitrogen, 0.01 ppm total oxygen and argon, 0.1 ppm total methane and acetylene, 0.08 ppm carbon monoxide, 0.41 ppm carbon dioxide, and 0.05 ppm moisture. 1,1,2,2-Tetrachloroethane and trichloroethylene were not detected. This exceeds the purity requirements for hydrogen chloride specified in the current national standard GB / T 14602-2014 "Gaseous Hydrogen Chloride for Electronic Industry" (≥99.999 wt% and ≥99.9995 wt%). The average yield of electronic-grade hydrogen chloride prepared in this embodiment was 75.3%, and the yield of liquid hydrogen chloride with a purity of 99.9 wt% byproduct of the decarbonization step was 20.3%; the overall yield was 95.6%.

[0074] This embodiment also provides an intermittent production system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride, to implement the aforementioned method, including: a deolefination unit, a dehydration unit, a decarbonization unit, a purification unit, and a dust removal unit.

[0075] The deolefin removal unit includes: a pre-condenser 1, a crude product tank 2, a deolefin removal tower 3, a deolefin removal condenser 4, a deolefin removal reflux tank 5, and a recovery vessel 6. The inlet of the pre-condenser 1 is connected to the raw material gas source, and the outlet of the pre-condenser 1 is connected to the inlet of the crude product tank 2. The outlet of the crude product tank 2 is connected to the lower middle inlet of the deolefin removal tower 3. The top light component outlet of the deolefin removal tower 3 is connected to the inlet of the deolefin removal condenser 4, and the outlet of the deolefin removal condenser 4 is connected to the inlet of the deolefin removal reflux tank 5. The lower outlet of the deolefin removal reflux tank 5 is connected in parallel to the top reflux outlet of the deolefin removal tower 3 and the inlet of the deolefin removal transfer tank 7. The bottom high-boiling-point outlet of the deolefin removal tower 3 is connected to the inlet of the recovery vessel 6.

[0076] The dehydration unit includes: a deolefin transfer tank 7, a dehydration tower 8, a dehydration condenser 9, and a dehydration water transfer tank 10. The outlet of the deolefin transfer tank 7 is connected to the lower inlet of the dehydration tower 8; the top outlet of the dehydration tower 8 is connected to the inlet of the dehydration condenser 9; the outlet of the dehydration condenser 9 is connected to the top inlet of the dehydration water transfer tank 10; and the bottom outlet of the dehydration water transfer tank 10 is connected to the decarbonization tower 11.

[0077] The decarbonization unit includes: a decarbonization tower 11, a decarbonization condenser 12, a recovery condenser 13, a recovery buffer tank 14, a 3N-grade buffer tank 15, and a chemical-grade buffer tank 16. The top outlet of the decarbonization tower 11 is connected to the inlet of the decarbonization condenser 12; the uncondensed gas outlet of the decarbonization condenser 12 is connected to the inlet of the recovery condenser 13; the liquid outlet of the recovery condenser 13 is connected to the inlet of the recovery buffer tank 14; the outlet of the recovery buffer tank 14 is connected to the inlet of the 3N-grade buffer tank 15; and the uncondensed gas outlet of the recovery condenser 13 is connected to the hydrochloric acid preparation process. The liquid outlet of the decarbonization condenser 12 is connected in parallel to the top reflux port of the decarbonization tower 11 and the inlet of the chemical-grade buffer tank 16; the outlet of the chemical-grade buffer tank 16 is connected to the inlet of the impurity removal transfer tank 17.

[0078] The impurity removal unit includes: an impurity removal transfer tank 17 and an impurity removal tower 18. The discharge port of the impurity removal transfer tank 17 is connected to the bottom inlet of the impurity removal tower 18, and the top discharge port of the impurity removal tower 18 is connected to the lower inlet of the dust removal tower 19.

[0079] The dust removal unit includes: a dust removal tower 19, a dust removal condenser 20, a dust removal reflux tank 21, and an electronic-grade buffer tank 22. The top outlet of the dust removal tower 19 is connected to the inlet of the dust removal condenser 20, and the outlet of the dust removal condenser 20 is connected to the inlet of the dust removal reflux tank 21; the outlet of the dust removal reflux tank 21 is connected to the inlet of the electronic-grade buffer tank 22.

[0080] Example 2

[0081] The batch production method and system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production, in Example 2 is the same as in Example 1. The difference is that the raw gas in this batch processed in Example 2 contains 99.5334 wt% hydrogen chloride, 48 ppm hydrogen, 207 ppm nitrogen, 198 ppm total oxygen and argon, 915 ppm carbon monoxide, 2314 ppm carbon dioxide, 2 ppm total methane and acetylene, 15 ppm moisture, 716 ppm 1,1,2,2-tetrachloroethane, 131 ppm trichloroethylene, 59 ppm 1,1,2-trichloroethane, and 73 ppm tetrachloroethylene.

[0082] Testing revealed that the electronic-grade hydrogen chloride prepared in this embodiment contained 99.999932 wt% hydrogen chloride, 0.01 ppm hydrogen, 0.01 ppm nitrogen, no detectable oxygen or argon, 0.1 ppm total methane and acetylene, 0.08 ppm carbon monoxide, 0.42 ppm carbon dioxide, 0.06 ppm moisture, and no detectable 1,1,2,2-tetrachloroethane, trichloroethylene, or tetrachloroethane. This exceeds the purity requirements (≥99.999 wt% and ≥99.9995 wt%) specified in the current national standard GB / T 14602-2014 "Gaseous Hydrogen Chloride for Electronic Industry". The average yield of electronic-grade hydrogen chloride prepared in this embodiment was 74.9%, and the yield of liquid hydrogen chloride with a purity of 99.9 wt% byproduct of the decarbonization step was 20.2%; the overall yield was 95.1%.

[0083] Example 3

[0084] The batch production method and system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production, in Example 3 is the same as in Example 1. The difference is that the batch of raw material gas processed in Example 3 contains 99.5037 wt% hydrogen chloride, 48 ppm hydrogen, 232 ppm nitrogen, 188 ppm total oxygen and argon, 1367 ppm carbon monoxide, 2045 ppm carbon dioxide, 2 ppm total methane and acetylene, 15 ppm moisture, 822 ppm 1,1,2,2-tetrachloroethane, 103 ppm trichloroethylene, 68 ppm 1,1,2-trichloroethane, and 61 ppm tetrachloroethylene.

[0085] Testing revealed that the electronic-grade hydrogen chloride prepared in this embodiment contained 99.999928 wt% hydrogen chloride, 0.01 ppm hydrogen, 0.01 ppm nitrogen, no detectable oxygen or argon, 0.1 ppm total methane and acetylene, 0.09 ppm carbon monoxide, 0.45 ppm carbon dioxide, 0.06 ppm moisture, and no detectable 1,1,2,2-tetrachloroethane, trichloroethylene, or tetrachloroethane. This exceeds the purity requirements (≥99.999 wt% and ≥99.9995 wt%) specified in the current national standard GB / T 14602-2014 "Gaseous Hydrogen Chloride for Electronic Industry". The average yield of electronic-grade hydrogen chloride prepared in this embodiment was 75.0%, and the yield of liquid hydrogen chloride with a purity of 99.9 wt% byproduct of the decarbonization step was 20.0%; the overall yield was 95.0%.

[0086] As can be seen from Examples 1-3, the intermittent production method and system for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, effectively removes residual chlorine-containing organic matter and other impurities from the hydrogen chloride gas by sequentially performing de-olefin treatment, dehydration treatment, decarbonization treatment, impurity removal treatment, and dust removal treatment. This significantly reduces the content of gaseous impurities, and the purity and impurity content of the obtained hydrogen chloride product meet the quality requirements for electronic-grade hydrogen chloride. The gaseous impurities of hydrogen chloride can be reduced to 0.7 ppm or below, and the moisture content to 80 ppb or below. At the same time, it can effectively adapt to fluctuations in the impurity content of the hydrogen chloride gas from ethylene chloride production, exhibiting strong process adaptability and stable quality of the obtained hydrogen chloride product, which can meet the requirements of large-scale industrial processing.

[0087] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0088] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A batch production method for electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of vinyl chloride production, characterized in that, It consists of sequential processes of deolefin removal, dehydration, decarbonization, impurity removal, and dust removal. The deolefin treatment method is as follows: hydrogen chloride gas, a by-product of ethylene chloride, is condensed and liquefied, and then fed into the deolefin tower (3). High-boiling substances are removed by distillation, and the light components at the top of the tower are collected and condensed to obtain deolefin condensate. The dehydration treatment method is as follows: after the deolefin condensate is heated and vaporized, it is fed into a dehydration tower (8) filled with water-absorbing packing. After contacting the water-absorbing packing for dehydration, it is condensed to obtain dehydrated condensate. In the dehydration process, the working pressure of the dehydration tower (8) is controlled at 3.6-4.2 MPa; the water-absorbing packing is composed of anhydrous calcium chloride spikes and 3A molecular sieves; The weight ratio of anhydrous calcium chloride spiked balls to 3A molecular sieve is 7-7.5:2.5-3; The decarbonization process is as follows: the dehydration condensate is fed into the decarbonization tower (11), and the pressure at the top of the decarbonization tower (11) is controlled to be 4.2-4.8 MPa. The dehydration condensate is heated and vaporized into hydrogen chloride gas, which is then condensed in the decarbonization condenser (12). The condensate from the decarbonization condenser (12) is completely refluxed back to the decarbonization tower (11). The uncondensed gas from the decarbonization condenser (12) is condensed in the recovery condenser (13), and the condensate from the recovery condenser (13) is collected to obtain liquid hydrogen chloride. The uncondensed gas from the recovery condenser (13) is collected and used to prepare hydrochloric acid. The condensate from the decarbonization condenser (12) is completely refluxed until the content of light component impurities meets the predetermined requirements. Then, the material in the decarbonization tower (11) is completely evaporated, and the decarbonization treatment liquid is obtained by condensation and recovery. The method of removing impurities is as follows: after the decarbonization liquid is heated and vaporized, it is fed into the impurity removal tower (18) filled with silicon-aluminum molecular sieve. After contacting the silicon-aluminum molecular sieve to remove impurity components, it is filtered and fed into the dust removal tower (19). In the impurity removal process, the silica-alumina molecular sieve is composed of 13X molecular sieve and 3A molecular sieve; the weight ratio of 13X molecular sieve to 3A molecular sieve is 3-3.5:

1. In the impurity removal process, the impurity components removed by the silica-alumina molecular sieve are nitrogen, oxygen, argon, carbon monoxide, carbon dioxide, and methane. The dust removal process involves a dust removal tower (19) receiving hydrogen chloride gas from a purification tower (18) to remove solid dust and residual high-boiling substances, thereby obtaining electronic-grade hydrogen chloride.

2. The batch production method for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, as described in claim 1, is characterized in that... The deolefin treatment method is as follows: hydrogen chloride gas, a byproduct of ethylene chloride production, is condensed and liquefied to obtain crude hydrogen chloride liquid; the crude hydrogen chloride liquid is fed into the deolefin tower (3) and the bottom liquid level is maintained at 60-90%; the top pressure of the deolefin tower (3) is controlled at 1.6-2.2 MPa and the bottom temperature is controlled at -8℃ to -4℃ for deolefin treatment; during the deolefin treatment, the light components at the top of the tower are condensed to obtain deolefin condensate; a portion of the deolefin condensate is returned to the deolefin tower (3).

3. The batch production method for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, as described in claim 2, is characterized in that... The reflux ratio of the deolefin condensate is controlled at 1-1.2:1; The flow rate of the deolefin condensate returned to the deolefin tower (3) is 80-200 kg / h.

4. The batch production method for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, as described in claim 1, is characterized in that... In the decarbonization process, the flow rate of the condensate in the decarbonization condenser (12) is 500-900 kg / h; the flow rate of the uncondensed gas in the decarbonization condenser (12) is 20-60 kg / h. The condensate of the decarbonization condenser (12) is fully refluxed until the content of light component impurities meets the following requirements: hydrogen content < 0.1 ppm, nitrogen content < 5 ppm, total oxygen and argon content < 5 ppm, total hydrocarbon content < 1 ppm, carbon monoxide content < 15 ppm, and carbon dioxide content < 80 ppm.

5. The batch production method for preparing electronic-grade hydrogen chloride using hydrogen chloride gas, a byproduct of ethylene chloride production, as described in claim 1, is characterized in that... The dust removal process is as follows: the dust removal tower (19) receives hydrogen chloride gas from the impurity removal tower (18), the pressure at the top of the dust removal tower (19) is controlled at 3.6-4.2 MPa, and the temperature at the bottom of the tower is 14-22℃. After the light components at the top of the dust removal tower (19) are condensed, the condensate is completely returned to the dust removal tower (19) until the condensate meets the specifications of electronic grade hydrogen chloride. The condensate is collected to obtain electronic grade hydrogen chloride.

6. A production system for implementing the method as described in any one of claims 1-5, characterized in that, It consists of a deolefin removal unit, a dehydration unit, a decarbonization unit, a purification unit, and a dust removal unit connected in sequence; The deolefin removal unit includes: a pre-condenser (1), a crude product tank (2), a deolefin removal tower (3), a deolefin removal condenser (4), a deolefin removal reflux tank (5), and a recovery vessel (6). The dehydration unit includes: a deolefin transfer tank (7), a dehydration tower (8), a dehydration condenser (9), and a dehydration transfer tank (10). The decarbonization unit includes: a decarbonization tower (11), a decarbonization condenser (12), a recovery condenser (13), a recovery buffer tank (14), a 3N-grade buffer tank (15), and a chemical-grade buffer tank (16). The impurity removal unit includes: an impurity removal transfer tank (17) and an impurity removal tower (18). The dust removal unit includes: a dust removal tower (19), a dust removal condenser (20), a dust removal return tank (21), and an electronic-grade buffer tank (22).

7. The production system according to claim 6, characterized in that, In the decarbonization unit, the top outlet of the decarbonization tower (11) is connected to the inlet of the decarbonization condenser (12), and the liquid outlet of the decarbonization condenser (12) is connected to the top reflux outlet of the decarbonization tower (11); the uncondensed gas outlet of the decarbonization condenser (12) is connected to the inlet of the recovery condenser (13); the liquid outlet of the recovery condenser (13) is connected to the inlet of the recovery buffer tank (14); and the uncondensed gas outlet of the recovery condenser (13) is connected to the hydrochloric acid preparation section.

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