Novel energy-saving environment-friendly refrigerant raw material preparation system

Abstract

The invention relates to the technical field of refrigerant raw material preparation, and discloses a novel energy-saving environment-friendly refrigerant raw material preparation system which comprises a raw material preparation and supply unit, a reaction and separation unit and a refining unit which are connected in sequence, the reaction and separation unit comprises a mixer, a reflux device, a reactor, a cooling separation device, a membrane type absorption device and a tail gas tower which are connected in sequence; the refining unit comprises an azeotropic tower, a rectifying tower I and a rectifying tower II which are connected in sequence, and is used for performing dehydration, deacidification and rectifying purification on the separated crude chlorinated liquid to obtain a high-purity carbon tetrachloride product; by optimizing the technological process of the raw material preparation and supply unit, the reaction and separation unit and the refining unit, efficient, environment-friendly and energy-saving production of carbon tetrachloride is realized; the problem that the production raw material carbon tetrachloride of the fourth-generation refrigerant is insufficient is solved, the production cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of refrigerant raw material preparation technology, specifically a novel energy-saving and environmentally friendly refrigerant raw material preparation system. Background Technology

[0002] While the second and third generation refrigerants currently available on the market have a small impact on the ozone layer, they are still greenhouse gases, and their large-scale use will accelerate global warming. Fourth generation refrigerants, such as R1234ze and R1234yf, do not contain chlorine, do not damage the ozone layer, and have extremely low greenhouse effects. Therefore, they are hailed as the most commercially promising fourth-generation refrigerants and are also known as new energy-saving and environmentally friendly refrigerants.

[0003] The synthesis route for R1234ze is as follows: CCl4+C2HCl→R240fa→R245fa→R1234ze; The synthesis route for R1234yf is as follows: CCl4+C2H2→R250fa→R1230xa→R1233xf→R1234yf.

[0004] The synthesis routes of fourth-generation refrigerants R1234ze and R1234yf both require CCl4 (carbon tetrachloride) as an initial raw material. According to the Montreal Protocol on Substances that Deplete the Ozone Layer, the production and use of carbon tetrachloride were completely banned from January 1, 2010, except for special applications. The carbon tetrachloride byproduct of methane chloride production is primarily converted into tetrachloroethylene. This results in insufficient production of fourth-generation refrigerants, leading to excessively high costs and prices, severely hindering the replacement process of fourth-generation refrigerants.

[0005] Based on the current production quota of 800,000 tons / year for third-generation refrigerants, the annual demand for carbon tetrachloride would increase by 1.2 million tons after replacing it with fourth-generation refrigerants. However, China's methane chloride production capacity is projected to reach 3.84 million tons / year in 2024, meaning that carbon tetrachloride production as a byproduct (assuming a 5% ratio) would be less than 200,000 tons / year. Therefore, seeking a legal source for producing carbon tetrachloride, a raw material for fourth-generation refrigerants, is urgently needed. Domestically, the supply of methane chloride products, dichloromethane and trichloromethane, exceeds demand, with production falling below 80% of capacity. The selling price is slightly higher than the cost price. Therefore, purchasing dichloromethane and trichloromethane products to produce new energy-saving and environmentally friendly refrigerant raw materials is the most reasonable choice. Summary of the Invention

[0006] The purpose of this invention is to provide a novel energy-saving and environmentally friendly refrigerant raw material preparation system to solve the problem of insufficient carbon tetrachloride as a raw material for the production of fourth-generation refrigerants, as mentioned in the background art.

[0007] In a first aspect, to achieve the above objectives, the present invention provides the following technical solution: a novel energy-saving and environmentally friendly refrigerant raw material preparation system, comprising a raw material preparation and supply unit, a reaction and separation unit, and a purification unit connected in sequence; The raw material preparation and supply unit is used to vaporize and superheat dichloromethane and / or trichloromethane with liquid chlorine respectively, and mix them in proportion to form raw material gas; The reaction and separation unit includes a mixer, a reflux device, a reactor, a cooling and separation device, a membrane absorption device, and a tail gas tower connected in sequence. It is used to perform a chlorination reaction on the raw material gas to generate a reaction gas containing carbon tetrachloride, and to cool, separate the gas and liquid, absorb hydrogen chloride, and purify the tail gas. The refining unit includes an azeotropic column, a first distillation column, and a second distillation column connected in sequence, used to dehydrate, deacidify, and purify the separated crude chlorinated liquid by distillation to obtain a high-purity carbon tetrachloride product.

[0008] The raw material preparation and supply unit includes a light component processing subsystem and a chlorine processing subsystem. The light component processing subsystem includes a light component storage tank, a light component receiving tank, a light component evaporator, and a light component superheater connected in sequence, for vaporizing and superheating dichloromethane and / or trichloromethane to approximately 90°C and 0.6 MPa.G. The chlorine treatment subsystem includes a liquid chlorine storage tank, a liquid chlorine vaporizer, and a chlorine superheater connected in sequence, for vaporizing and superheating the liquid chlorine to approximately 90°C and 1.2 MPa.G. The outlets of the light component superheater and the chlorine superheater are both connected to the mixer.

[0009] The light component storage tank is used to store dichloromethane and / or trichloromethane, and a light component pump is provided on the pipeline between the light component storage tank and the light component receiving tank. The outlet at the bottom of the light component receiving tank is connected to the inlet of the light component evaporator through a pipeline. The light component evaporator is used to vaporize dichloromethane and / or trichloromethane, and the vaporized dichloromethane and / or trichloromethane are returned to the light component receiving tank. The outlet at the top of the light component receiving tank is connected to the inlet of the light component superheater via a pipeline. The vaporized dichloromethane and / or trichloromethane that flows back to the light component receiving tank flows into the light component superheater, which is used to superheat the vaporized dichloromethane and / or trichloromethane to approximately 90°C and 0.6 MPa.G.

[0010] The liquid chlorine storage tank is used to store liquid chlorine, and a liquid chlorine pump is installed on the pipeline between the liquid chlorine storage tank and the liquid chlorine vaporizer. A chlorine buffer tank is installed on the pipeline between the liquid chlorine vaporizer and the chlorine superheater. The liquid chlorine vaporizer is used to vaporize liquid chlorine, which forms chlorine gas and is stored in a chlorine buffer tank. The chlorine gas in the buffer tank flows to the chlorine superheater, which is used to superheat the chlorine gas to about 90°C and 1.2 MPa.G.

[0011] The reactor is equipped with an electric heater, and the operating temperature of the reactor is 430℃-450℃, and the operating pressure is 0.05MPa.G. The top outlet of the reactor is connected to a release tank, which serves as a buffer space for pressure relief. The cooling and separation device includes a primary air cooler, a secondary air cooler, a carbon black separator, a tertiary condenser, and a phase separator connected in sequence. The inlet of the primary air cooler is connected to the outlet of the reactor. The outlet of the primary air cooler is divided into two paths: one path is connected to the reflux device through a pipeline to provide reflux gas, and the other path is connected in sequence to the secondary air cooler, carbon black separator, tertiary condenser and phase separator. The liquid outlet of the phase separator is connected to the crude chlorination liquid storage tank, and the gas outlet is connected to the membrane absorption device.

[0012] The membrane absorption device includes a primary membrane absorber and a secondary membrane absorber connected in series. The top air inlet of the first-stage membrane absorber is connected to the gas outlet of the phase separator, the bottom liquid outlet of the first-stage membrane absorber is connected to the crude acid separator, and the absorbent inlet of the first-stage membrane absorber is connected to the bottom dilute acid outlet of the second-stage membrane absorber. The top air inlet of the secondary membrane absorber is connected to the top air outlet of the primary membrane absorber, and the absorbent inlet of the secondary membrane absorber is connected to the circulating acid outlet of the tail gas tower. The inlet of the tail gas tower is connected to the top outlet of the secondary membrane absorber. The top of the tail gas tower is equipped with an industrial water inlet and a circulating acid inlet. The bottom outlet of the tail gas tower is partially circulated back into the tower through the tail gas tower circulation pump. The top outlet of the tail gas tower is connected to the external alkaline washing and incineration system.

[0013] The bottom outlet of the primary membrane absorber is connected to a crude acid separator, which is used to separate and recover hydrochloric acid and chloride. The overflow port at the top of the crude acid separator is connected to the hydrochloric acid buffer tank, and the bottom outlet of the crude acid separator is connected to the solid alkali dryer through liquid level control. The middle outlet of the hydrochloric acid buffer tank is connected to the hydrochloric acid storage tank via a hydrochloric acid transfer pump, the bottom outlet of the hydrochloric acid storage tank is connected to the hydrochloric acid loading pump, and the bottom outlet of the hydrochloric acid buffer tank is connected back to the crude acid separator via an organic matter recovery pump. The outlet of the solid alkali dryer is connected to the crude chlorination liquid storage tank.

[0014] This also includes: An azeotropic tower feed pump, the inlet of which is connected to a crude chlorination liquid storage tank, and the outlet of which is connected to an azeotropic tower; The azeotropic tower is equipped with an azeotropic tower reboiler at the bottom and an azeotropic tower top condenser at the top. The bottom outlet of the azeotropic tower is connected back to the crude chlorination liquid storage tank through the bottom outlet cooler. An alkaline washing separator is provided, the inlet of which is connected to the material from the azeotropic tower, and the heavy phase outlet of the alkaline washing separator is circulated or discharged through an alkaline washing pump.

[0015] This also includes: A crude chlorination liquid pump is provided, with its inlet connected to the crude chlorination liquid storage tank and its outlet connected to the feed inlet of a distillation column. The crude chlorination liquid in the storage tank is then dried by a crude chlorination liquid dryer through self-circulation to remove moisture from the crude chlorination liquid. The bottom of the first distillation column is equipped with a reboiler, the bottom liquid of the first distillation column is pumped to the second distillation column, and the top of the first distillation column is equipped with a condenser. The first distillation column dryer and the first distillation column reflux tank are connected in sequence to the outlet of the top condenser of the first distillation column. The outlet of the first distillation column reflux tank is divided into two paths by the first distillation column reflux pump. One path refluxes back to the top of the first distillation column, and the other path is connected to the light component storage tank. The bottom of the second distillation column is equipped with a reboiler, the bottom liquid of the second distillation column is discharged into the bottom liquid tank of the second distillation column by the bottom liquid pump, and the top of the second distillation column is equipped with a top condenser. The second distillation column dryer and the second distillation column reflux tank are connected in sequence to the outlet of the top condenser of the second distillation column. The outlet of the second distillation column reflux tank is divided into two paths by the second distillation column reflux pump. One path refluxes back to the top of the second distillation column, and the other path is connected to the detection tank. The outlet of the testing tank is equipped with a testing tank pump, which is used to pump qualified carbon tetrachloride products to the downstream refrigerant production unit. The outlet of the distillation column reboiler tank is equipped with a distillation column reboiler tank transfer pump, which is used to send the reboiler residue to the incineration plant.

[0016] Secondly, this invention provides a method for preparing high-purity carbon tetrachloride using the novel energy-saving and environmentally friendly refrigerant raw material preparation system described above, comprising the following steps: S1. Raw material pretreatment: Dichloromethane and / or trichloromethane are vaporized and superheated to approximately 90°C and 0.6 MPa.G in a light component evaporator and a light component superheater; liquid chlorine is vaporized and superheated to approximately 90°C and 1.2 MPa.G in a liquid chlorine vaporizer and a chlorine superheater; the two are then transported to a mixer for mixing at a volume ratio of 1:2-4. S2, Chlorination reaction: The mixed raw material gas from step S1 is mixed and diluted with the return gas from the primary air cooler through a reflux device, and then sent into the reactor to carry out the chlorination reaction at 430℃-450℃ and 0.05MPa.G to generate a reaction gas containing carbon tetrachloride and hydrogen chloride. S3. Separation and purification of reaction gas: The reaction gas from step S2 is cooled sequentially by a primary air cooler and a secondary air cooler, and after carbon black is removed by a carbon black separator, it enters a tertiary condenser for condensation. Gas-liquid separation is carried out in a phase separator to obtain crude chlorination liquid. The uncondensed gas is sequentially absorbed by a primary membrane absorber, a secondary membrane absorber, and a tail gas tower to absorb hydrogen chloride and capture residual chlorides. After purification, the tail gas is discharged. S4. Refining of crude chlorinated liquid: The crude chlorinated liquid obtained in step S3 is subjected to azeotropic dehydration and deacidification, separation of light components in distillation column one, and purification by distillation in distillation column two to finally obtain carbon tetrachloride product with a purity of not less than 99.99 wt%.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves efficient, environmentally friendly, and energy-saving carbon tetrachloride production by optimizing the process flow of the raw material preparation and supply unit, reaction and separation unit, and refining unit. Specifically, the raw material preparation and supply unit employs vaporization and superheating technology to ensure a stable supply and precise proportion of raw material gas; the reaction and separation unit achieves a high-conversion chlorination reaction through precise control of reaction conditions, and effectively separates crude chlorinated liquid and purifies tail gas through multi-stage cooling separation and membrane absorption; the refining unit obtains high-purity carbon tetrachloride product through azeotropic dehydration and deacidification, distillation purification, and other steps. This not only solves the problem of insufficient carbon tetrachloride as a raw material for the production of fourth-generation refrigerants, but also reduces production costs and improves production efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the novel energy-saving and environmentally friendly refrigerant raw material preparation system of the present invention; Figure 2 This is a schematic diagram of the raw material preparation and supply unit structure of the present invention; Figure 3 This is a schematic diagram of the reaction and separation unit structure of the present invention; Figure 4 for Figure 3 Schematic diagram of the left-hand side of the structure; Figure 5 for Figure 3 A schematic diagram of the middle side structure; Figure 6 This is a schematic diagram of the refining unit structure of the present invention; Figure 7 for Figure 6 Schematic diagram of the left side structure; Figure 8 for Figure 6 A schematic diagram of the structure on the right side.

[0019] In the diagram: 1. Light component storage tank; 2. Light component pump; 3. Light component receiving tank; 4. Light component evaporator; 5. Light component superheater; 6. Liquid chlorine storage tank; 7. Liquid chlorine pump; 8. Liquid chlorine vaporizer; 9. Chlorine buffer tank; 10. Chlorine superheater; 11. Mixer; 12. Reflux device; 13. Reactor; 14. Reactor electric heater; 15. Release tank; 161. Primary air cooler; 162. Secondary air cooler; 17. Carbon black separator; 18. Tertiary condenser; 19. Phase separator; 201. Primary membrane absorber; 202. Secondary membrane absorber; 21. Tail gas tower; 22. Tail gas tower circulation pump; 23. Crude acid separator; 24. Hydrochloric acid buffer. 25. Tank; 26. Organic matter recovery pump; 27. Hydrochloric acid transfer pump; 28. Hydrochloric acid storage tank; 29. ​​Hydrochloric acid loading pump; 30. Solid alkali dryer; 31. Crude chlorination liquid storage tank; 32. Crude chlorination liquid pump; 33. Crude chlorination liquid dryer; 34. Alkali washing separator; 35. Alkali washing pump; 36. Azeotropic tower feed pump; 37. Azeotropic tower; 38. Azeotropic tower reboiler; 39. Azeotropic tower top condenser; 30. Azeotropic tower bottom cooler. 40. Distillation column 1; 41. Reboiler of distillation column 1; 42. Bottom liquid pump of distillation column 1; 43. Top condenser of distillation column 1; 44. Dryer of distillation column 1; 45. Reflux tank of distillation column 1; 46. Reflux pump of distillation column 1; 47. Distillation column 2; 48. Reboiler of distillation column 2; 49. Bottom liquid pump of distillation column 2; 50. Bottom liquid tank of distillation column 2; 51. Bottom liquid tank transfer pump of distillation column 2; 52. Top condenser of distillation column 2; 53. Dryer of distillation column 2; 54. Reflux tank of distillation column 2; 55. Reflux pump of distillation column 2; 56. Detection tank; 57. Detection tank pump. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Example 1: Please refer to Figures 1-8 The present invention provides a technical solution: a novel energy-saving and environmentally friendly refrigerant raw material preparation system, comprising a raw material preparation and supply unit, a reaction and separation unit, and a purification unit connected in sequence; The raw material preparation and supply unit is used to vaporize and superheat dichloromethane and / or trichloromethane with liquid chlorine respectively, and mix them in proportion to form raw material gas; The reaction and separation unit includes a mixer 11, a reflux device 12, a reactor 13, a cooling and separation device, a membrane absorption device, and a tail gas tower 21 connected in sequence. It is used to make the raw gas undergo a chlorination reaction to generate a reaction gas containing carbon tetrachloride, and to cool, separate the gas and liquid, absorb hydrogen chloride, and purify the tail gas. The refining unit includes an azeotropic tower 36, a first distillation tower 40, and a second distillation tower 47 connected in sequence, which are used to dehydrate, deacidify, and purify the separated crude chlorinated liquid by distillation to obtain a high-purity carbon tetrachloride product.

[0022] Specifically, the novel energy-saving and environmentally friendly refrigerant raw material preparation system of this application is used to produce high-purity carbon tetrachloride, which can be used as the initial raw material for the fourth-generation novel energy-saving and environmentally friendly refrigerant; the raw material preparation and supply unit is the starting part of the system, and its function is to pre-treat the two main raw materials, dichloromethane and / or trichloromethane and liquid chlorine, which enter the system. The pretreatment process typically involves converting liquid raw materials into gaseous state and heating them to a specific temperature to ensure the smooth and efficient progress of subsequent reactions. The reaction and separation unit is the core reaction area and preliminary separation area of ​​the system. This unit is responsible for chlorinating the pretreated raw material gas to generate a reaction gas containing the target product, carbon tetrachloride. Subsequently, this unit also performs preliminary cooling and gas-liquid separation on the reaction gas, absorbs the reaction byproduct hydrogen chloride, and purifies the tail gas to reduce environmental emissions. The refining unit is the final processing stage of the system. Its main task is to deeply purify the crude chlorination liquid obtained from the reaction and separation unit. This unit removes impurities from the crude chlorination liquid through dehydration, deacidification, and distillation purification, ultimately obtaining a carbon tetrachloride product that meets high purity standards.

[0023] Furthermore, dichloromethane and / or trichloromethane are organic raw materials used in the chlorination reaction in this system. These compounds can be converted into carbon tetrachloride under chlorination conditions. Liquid chlorine is an inorganic raw material that provides chlorine in this system and participates in the reaction as a chlorinating agent.

[0024] Furthermore, the chlorination reaction refers to the chemical reaction between dichloromethane and / or trichloromethane and chlorine under specific conditions to produce carbon tetrachloride; the reaction gas containing carbon tetrachloride refers to the gas mixture containing carbon tetrachloride, unreacted raw materials, byproduct hydrogen chloride, and other impurities discharged from reactor 13 after the chlorination reaction is completed; cooling, gas-liquid separation, hydrogen chloride absorption, and tail gas purification are the key steps in the reaction gas treatment process. Cooling aims to lower the temperature of the reaction gas; gas-liquid separation is used to separate gaseous components from liquid components; hydrogen chloride absorption is used to remove the reaction byproduct hydrogen chloride; tail gas purification is used to treat the remaining gas to meet emission standards; crude chlorinated liquid refers to a liquid mixture containing carbon tetrachloride, water, acid, and other organic impurities obtained after preliminary cooling and gas-liquid separation; dehydration, deacidification, and distillation purification are the main operations in the refining unit for purifying crude chlorinated liquid. Dehydration aims to remove water; deacidification aims to remove acidic substances; distillation purification utilizes the difference in boiling points of the components to achieve component separation through multiple vaporization and condensation, thereby improving the purity of carbon tetrachloride; high-purity carbon tetrachloride product refers to carbon tetrachloride that has reached a specific purity standard after being processed by the refining unit and can be directly used to produce the fourth-generation new energy-saving and environmentally friendly refrigerant.

[0025] The raw material preparation and supply unit pretreats dichloromethane and / or trichloromethane with liquid chlorine to bring them to a suitable state for the chlorination reaction, and then mixes them in a specific ratio to form a raw material gas. Specifically, dichloromethane and / or trichloromethane can be stored in an atmospheric pressure light component storage tank 1, and then pumped to a light component evaporator 4 for vaporization via a light component pump 2. Afterward, it enters a light component superheater 5 for superheating to ensure complete vaporization and reaching the required reaction temperature. Liquid chlorine can be stored in a liquid chlorine storage tank 6, and then pumped to a liquid chlorine vaporizer 8 via a liquid chlorine pump 7 to be converted into chlorine gas, and then heated to the reaction temperature via a chlorine superheater 10. The two superheated gases are then mixed in a mixer 11 at a volume ratio of 1:2-4 to form a homogeneous raw material gas.

[0026] Specifically, mixer 11 is used to thoroughly mix the raw material gas from the raw material preparation supply unit with the return gas from the reflux device 12. Mixer 11 can be a jet mixer, achieving rapid and uniform mixing through the shearing action of high-speed airflow; or it can be a mixing tank with a stirring paddle, promoting gas mixing through mechanical stirring. The function of reflux device 12 is to provide dilution gas to control the temperature and reaction rate within reactor 13, while simultaneously recovering some unreacted materials. Reflux device 12 can be a simple bypass line that reintroduces some of the cooled reaction product gas into mixer 11; or it can be a circulation loop with a compressor that pressurizes the gas and returns it. Reactor 13 is the core equipment for the chlorination reaction. In reactor 13, the raw material gas undergoes a chlorination reaction under high temperature and high pressure conditions, generating a reaction gas containing carbon tetrachloride. An empty tube reactor can be used, relying on high temperature to promote the thermal chlorination reaction. Cooling and separation device is used to cool the high-temperature reaction gas discharged from reactor 13 and to achieve gas-liquid separation. The cooling and separation device can consist of multiple heat exchangers connected in series. For example, it can first use an air cooler for initial cooling, and then use a water-cooled condenser for deep cooling. Gas-liquid separation can be carried out in a gravity separator, utilizing the density difference between gas and liquid to achieve separation; or it can be carried out in a cyclone separator, separating liquid droplets by centrifugal force. A membrane absorption device is used for the efficient absorption of hydrogen chloride in the reaction gas. The membrane absorption device can use a packed tower filled with absorbent liquid, achieving hydrogen chloride absorption through countercurrent gas-liquid contact; or it can use a spray tower, contacting the gas with the sprayed absorbent liquid. The tail gas tower 21 is used to further purify the tail gas discharged from the membrane absorption device, removing residual harmful substances to meet emission standards. The tail gas tower 21 can be a multi-stage scrubbing tower, treating the tail gas stage by stage with different scrubbing liquids; or it can be an activated carbon adsorption tower, adsorbing trace organic matter in the tail gas.

[0027] Specifically, the azeotropic column 36 is used for dehydration and deacidification of the crude chlorination liquid. The azeotropic column 36 can be a conventional plate column or packed column. An azeotropic agent is added to form an azeotrope with water, thereby separating water from the crude chlorination liquid. Simultaneously, an alkaline solution can be introduced into the column to neutralize acidic substances in the crude chlorination liquid. The first distillation column 40 is used to separate light components from the crude chlorination liquid. The first distillation column 40 can be a multi-stage plate distillation column. By controlling the temperature and pressure at the top and bottom of the column, the lighter components with lower boiling points are separated from the top, while carbon tetrachloride and heavy components are discharged from the bottom. The second distillation column 47 is used to further purify the material discharged from the first distillation column 40 to obtain a high-purity carbon tetrachloride product. The second distillation column 47 can also be a high-efficiency plate distillation column. Through more precise temperature and pressure control, carbon tetrachloride is separated from trace heavy components and residual impurities, thereby achieving the required product purity.

[0028] In summary, in the raw material preparation and supply unit, dichloromethane and liquid chlorine are introduced as the main raw materials. Dichloromethane is stored in an atmospheric pressure light component storage tank 1 and is transported to a light component evaporator 4 for vaporization via a light component pump 2. The vaporized gas then enters a light component superheater 5 for superheating treatment to ensure complete vaporization and reaching the required reaction temperature. Liquid chlorine is stored in a liquid chlorine storage tank 6 and is transported to a liquid chlorine vaporizer 8 via a liquid chlorine pump 7 to be converted into chlorine gas. The chlorine gas is then heated to the reaction temperature via a chlorine superheater 10. The two superheated gases are thoroughly mixed in a mixer 11 at a volume ratio of 1:2-4 to form a homogeneous raw material gas.

[0029] In the reaction and separation unit, mixer 11 mixes the feed gas from the feed preparation and supply unit with the reflux gas from reflux device 12. Reflux device 12 provides dilution gas via a bypass line or a circulation loop with a compressor to control the temperature and reaction rate within reactor 13 and to recover some unreacted materials. Reactor 13, as the core equipment for the chlorination reaction, allows the feed gas to undergo a chlorination reaction under high temperature and high pressure conditions of 430°C - 450°C and 0.05 MPa.G, generating a reaction gas containing carbon tetrachloride.

[0030] The high-temperature reaction gas discharged from reactor 13 enters a cooling and separation device, which consists of multiple heat exchangers connected in series. The gas is first initially cooled by an air cooler, and then further cooled by a water-cooled condenser. The cooled gas undergoes gas-liquid separation in a gravity separator or cyclone separator to obtain gaseous components and a crude chlorination liquid. The gaseous components enter a membrane absorption device, which uses a packed tower or spray tower filled with absorbent liquid. Hydrogen chloride in the reaction gas is efficiently absorbed through countercurrent gas-liquid contact or by spraying the absorbent liquid into the gas. The tail gas discharged from the membrane absorption device enters a tail gas tower 21, which uses a multi-stage scrubbing tower or activated carbon adsorption tower to further purify the tail gas, removing residual harmful substances to meet emission standards.

[0031] In the refining unit, azeotropic column 36 dehydrates and deacidifies the crude chlorinated liquid. Azeotropic column 36 uses a conventional plate column or packed column, adding an azeotropic agent to form an azeotrope with water, separating the water from the crude chlorinated liquid. Simultaneously, an alkaline solution is introduced to neutralize the acidic substances in the crude chlorinated liquid. Distillation column 40 separates the light components from the dehydrated and deacidified crude chlorinated liquid using a multi-stage plate distillation column. By controlling the temperature and pressure at the top and bottom of the column, the lower-boiling-point light components are separated from the top, while carbon tetrachloride and heavy components are discharged from the bottom. Distillation column 47 further purifies the material discharged from distillation column 40 using a high-efficiency plate distillation column. Through more precise temperature and pressure control, carbon tetrachloride is separated from trace heavy components and residual impurities, ultimately yielding a carbon tetrachloride product with a purity of not less than 99.99 wt%.

[0032] The raw material preparation and supply unit includes a light component processing subsystem and a chlorine processing subsystem. The light component processing subsystem comprises a light component storage tank 1, a light component receiving tank 3, a light component evaporator 4, and a light component superheater 5 connected in sequence, used to vaporize and superheat dichloromethane and / or trichloromethane to approximately 90°C and 0.6 MPa.G. The chlorine processing subsystem comprises a liquid chlorine storage tank 6, a liquid chlorine vaporizer 8, and a chlorine superheater 10 connected in sequence, used to vaporize and superheat liquid chlorine to approximately 90°C and 1.2 MPa.G. The outlets of both the light component superheater 5 and the chlorine superheater 10 are connected to a mixer 11. The light component storage tank 1 stores dichloromethane and / or trichloromethane, and a light component pump 2 is installed on the pipeline between the light component storage tank 1 and the light component receiving tank 3. The outlet at the bottom of the light component receiving tank 3 is connected to the inlet of the light component evaporator 4 via a pipeline. The light component evaporator 4 is used to vaporize dichloromethane and / or trichloromethane. / or trichloromethane is vaporized, and the vaporized dichloromethane and / or trichloromethane are returned to the light component receiving tank 3; the outlet at the top of the light component receiving tank 3 is connected to the inlet of the light component superheater 5 by a pipeline, and the vaporized dichloromethane and / or trichloromethane returning to the light component receiving tank 3 flows into the light component superheater 5, which is used to superheat the vaporized dichloromethane and / or trichloromethane to about 90°C and 0.6 MPa.G, liquid chlorine The storage tank 6 is used to store liquid chlorine. A liquid chlorine pump 7 is installed on the pipeline between the liquid chlorine storage tank 6 and the liquid chlorine vaporizer 8. A chlorine buffer tank 9 is installed on the pipeline between the liquid chlorine vaporizer 8 and the chlorine superheater 10. The liquid chlorine vaporizer 8 is used to vaporize the liquid chlorine, and the vaporized liquid chlorine forms chlorine gas, which is stored in the chlorine buffer tank 9. The chlorine gas in the chlorine buffer tank 9 flows to the chlorine superheater 10, which is used to superheat the chlorine gas to about 90°C and 1.2 MPa.G.

[0033] The light component processing subsystem is responsible for processing light component feedstocks such as dichloromethane and / or trichloromethane; its function is to ensure that these light components are precisely vaporized and superheated to specific temperature and pressure conditions before entering the main reactor. The chlorine processing subsystem is responsible for processing liquid chlorine feedstock; its function is to ensure that liquid chlorine is precisely vaporized and superheated to specific temperature and pressure conditions before entering the main reactor 13.

[0034] The light component storage tank 1 is used to store liquid dichloromethane and / or trichloromethane to be processed. The storage tank can be an atmospheric or low-pressure tank and is usually equipped with a level gauge, thermometer and pressure gauge to monitor the storage status. Its material is usually corrosion-resistant, such as stainless steel or carbon steel lined with anti-corrosion material.

[0035] The light component receiving tank 3 is used to receive and buffer dichloromethane and / or trichloromethane from the light component storage tank 1, and serves as a feed buffer for the light component evaporator 4. This receiving tank is typically designed as a container with liquid level control to ensure the continuity and stability of the subsequent evaporation process.

[0036] The light component evaporator 4 is used to convert liquid dichloromethane and / or trichloromethane into gaseous form. This evaporator can be in the form of a shell-and-tube heat exchanger, a plate heat exchanger, or a submerged heater, and the heat required for vaporization is provided by an external heat source (such as steam, thermal oil, or electric heating).

[0037] The light component superheater 5 is used to further heat the vaporized dichloromethane and / or trichloromethane gas, raising its temperature above its saturation temperature to achieve a superheated state. This superheater can be in the form of an electric heater, a steam superheater, or a thermal oil superheater, ensuring that the gas reaches precise conditions of approximately 90°C and 0.6 MPa.G before entering the mixer 11.

[0038] Among them, the liquid chlorine storage tank 6 is used to store liquid chlorine. Since liquid chlorine is corrosive and toxic, the storage tank is usually a high-pressure vessel and is made of special materials (such as carbon steel or stainless steel). It is equipped with safety monitoring and control devices such as safety valves, pressure gauges, and level gauges.

[0039] Among them, the liquid chlorine vaporizer 8 is used to convert liquid chlorine into gaseous chlorine. The vaporizer can use steam heating, electric heating or ambient temperature heating to heat the liquid chlorine to above its boiling point so that it is completely vaporized.

[0040] The chlorine superheater 10 is used to further heat the vaporized chlorine gas to make its temperature higher than its saturation temperature and reach a superheated state. The superheater can be in the form of an electric heater, a steam superheater or a thermal oil superheater to ensure that the chlorine gas reaches the precise conditions of about 90°C and 1.2 MPa.G before entering the mixer 11.

[0041] The mixer 11 is used to uniformly mix the pretreated light component superheated gas and chlorine superheated gas according to a preset ratio, so as to provide uniform reactants for the subsequent chlorination reaction.

[0042] Specifically, firstly, the light component storage tank 1 ensures an ample supply of raw materials. Then, the light component pump 2 precisely delivers liquid dichloromethane and / or trichloromethane to the light component receiving tank 3. In the light component receiving tank 3, the liquid raw material enters the light component evaporator 4 through a bottom pipe for vaporization. The vaporized gaseous dichloromethane and / or trichloromethane are not directly sent to the light component superheater 5, but instead flow back to the light component receiving tank 3, where they fully contact and balance with the liquid phase. This effectively avoids potential droplet entrainment or uneven gas phase at the outlet of the light component evaporator 4, ensuring the purity and stability of the gas entering the light component superheater 5. Simultaneously, the light component receiving tank 3 also acts as a buffer, smoothing out pressure fluctuations at the outlet of the light component evaporator 4. Next, stable gaseous dichloromethane and / or trichloromethane flowing out from the top of the light component receiving tank 3 enter the light component superheater 5, where they are precisely heated to about 90°C and maintained at a pressure of about 0.6 MPa.G, providing an ideal feed gas state for subsequent mixing with chlorine in the mixer 11 and for the chlorination reaction. A liquid chlorine storage tank 6 is used to store liquid chlorine. A liquid chlorine pump 7 is installed on the pipeline between the liquid chlorine storage tank 6 and the liquid chlorine vaporizer 8. A chlorine buffer tank 9 is installed on the pipeline between the liquid chlorine vaporizer 8 and the chlorine superheater 10. The liquid chlorine vaporizer 8 is used to vaporize the liquid chlorine, and the vaporized liquid chlorine forms chlorine gas, which is stored in the chlorine buffer tank 9. The chlorine gas in the chlorine buffer tank 9 flows to the chlorine superheater 10, which is used to superheat the chlorine gas to about 90°C and 1.2 MPa.G.

[0043] The reactor 13 is equipped with a reactor electric heater 14. The operating temperature of the reactor 13 is 430℃-450℃, and the operating pressure is 0.05MPa.G. The top outlet of the reactor 13 is connected to a release tank 15, which serves as a buffer space for pressure relief. The cooling and separation device includes a primary air cooler 161, a secondary air cooler 162, a carbon black separator 17, a tertiary condenser 18, and a phase separator 19 connected in sequence. The inlet of the primary air cooler 161 is connected to the outlet of the reactor 13. The outlet of the primary air cooler 161 is divided into two paths. One path is connected to the reflux device 12 through a pipeline to provide reflux gas, and the other path is connected to the secondary air cooler 162, the carbon black separator 17, the tertiary condenser 18, and the phase separator 19 in sequence. The liquid outlet of the phase separator 19 is connected to the crude chlorination liquid storage tank 30, and the gas outlet is connected to the membrane absorption device.

[0044] Specifically, the reactor electric heater 14 provides the necessary heat to the reactor 13 to maintain it within an operating temperature range of 430℃-450℃, ensuring the chlorination reaction proceeds smoothly under high-temperature conditions. During the reaction, due to the exothermic reaction and changes in the physical properties of the reactants and products, the pressure inside the reactor 13 is maintained at 0.05 MPa.G. When the pressure inside the reactor 13 exceeds the set value for some reason (such as an overly vigorous reaction), the release tank 15 connected to the top outlet of the reactor 13 acts as a pressure relief buffer, preventing the reactor 13 from becoming dangerous due to excessive pressure.

[0045] The high-temperature reaction gas discharged from the top outlet of reactor 13 first enters the primary air cooler 161 for preliminary cooling. The primary air cooler 161 uses air as a cooling medium to reduce the temperature of the reaction gas through heat exchange. The reaction gas at the outlet of the primary air cooler 161 is divided into two paths. One path is connected to the reflux device 12 through a pipeline and returns to the mixer 11 as reflux gas to control the temperature and reaction rate in reactor 13 and recover some unreacted materials. The other path enters the secondary air cooler 162, carbon black separator 17, tertiary condenser 18, and phase separator 19 in sequence for further cooling and separation.

[0046] The secondary air cooler 162 continues to cool the reaction gas, further reducing its temperature. After being cooled by the secondary air cooler 162, the reaction gas enters the carbon black separator 17. The carbon black separator 17 uses the principle of gas-solid separation to separate solid particles such as carbon black that may be carried in the reaction gas, preventing them from entering subsequent equipment and causing blockages or affecting product quality.

[0047] The reaction gas exiting the carbon black separator 17 enters the three-stage condenser 18 for deep cooling. The three-stage condenser 18 typically employs water cooling or other efficient cooling methods to cool the reaction gas to a lower temperature, causing most of the gaseous components to condense into liquid. The gas-liquid mixture cooled by the three-stage condenser 18 then enters the phase separator 19 for gas-liquid separation. Based on the density difference between the gas and liquid phases, the phase separator 19 separates the liquid crude chlorination solution from the gaseous components. The liquid crude chlorination solution is discharged from the liquid outlet of the phase separator 19 and connected to the crude chlorination solution storage tank 30 for storage; the gaseous components are discharged from the gas outlet of the phase separator 19 and connected to a membrane absorption unit for subsequent hydrogen chloride absorption treatment.

[0048] The membrane absorption device includes a primary membrane absorber 201 and a secondary membrane absorber 202 connected in series. The top air inlet of the primary membrane absorber 201 is connected to the gas outlet of the phase separator 19, the bottom liquid outlet of the primary membrane absorber 201 is connected to the crude acid separator 23, and the absorbent inlet of the primary membrane absorber 201 is connected to the bottom dilute acid outlet of the secondary membrane absorber 202. The top air inlet of the secondary membrane absorber 202 is connected to the top air outlet of the primary membrane absorber 201, and the absorbent inlet of the secondary membrane absorber 202 is connected to the circulating acid outlet of the tail gas tower 21. The inlet of the tail gas tower 21 is connected to the top outlet of the secondary membrane absorber 202. The top of the tail gas tower 21 is equipped with an industrial water inlet and a circulating acid inlet. The bottom outlet of the tail gas tower 21 is partially circulated back into the tower through the tail gas tower circulation pump 22. The top outlet of the tail gas tower 21 is connected to the external alkaline washing and incineration system.

[0049] Specifically, the gaseous components discharged from phase separator 19 first enter the primary membrane absorber 201. In the primary membrane absorber 201, the gaseous components come into countercurrent contact with the absorbent liquid introduced from the bottom dilute acid outlet of the secondary membrane absorber 202. The effective components in the absorbent liquid react chemically with the hydrogen chloride in the gaseous components, absorbing the hydrogen chloride. The gas absorbed by the primary membrane absorber 201 is discharged from its top outlet and enters the secondary membrane absorber 202 for further absorption treatment; while the absorbent liquid that has absorbed hydrogen chloride is discharged from the bottom outlet of the primary membrane absorber 201 and connected to the crude acid separator 23 for subsequent acid-liquid separation treatment.

[0050] The secondary membrane absorber 202 also employs a counter-current gas-liquid contact method. Its absorbent inlet is connected to the circulating acid outlet of the tail gas tower 21, and the circulating acid contains a certain concentration of absorbent components. Hydrogen chloride and other possible trace impurities that were not completely absorbed in the primary membrane absorber 201 are further reacted with the circulating acid in the secondary membrane absorber 202, resulting in more thorough absorption of hydrogen chloride. The gas absorbed by the secondary membrane absorber 202 is discharged from its top outlet, at which point the hydrogen chloride content in the gas has been significantly reduced, and then enters the tail gas tower 21.

[0051] The top of the tail gas tower 21 is equipped with an industrial water inlet and a circulating acid inlet. The industrial water is used to replenish the water consumed during the absorption process, while the circulating acid continues to participate in the purification of the tail gas. The bottom outlet of the tail gas tower 21 is partially circulated back into the tower via the tail gas tower circulation pump 22, forming a circulating absorption system to improve absorption efficiency and tail gas purification effect. After further purification by the tail gas tower 21, the residual harmful substance content of the tail gas meets the emission standards. Finally, the tail gas is connected from the top outlet of the tail gas tower 21 to an external alkaline scrubbing and incineration system for final tail gas treatment, ensuring that the tail gas emitted by the entire system meets environmental protection requirements.

[0052] The bottom outlet of the primary membrane absorber 201 is connected to the crude acid separator 23, which is used to separate and recover hydrochloric acid and chloride. The overflow port at the top of the crude acid separator 23 is connected to the hydrochloric acid buffer tank 24, and the bottom outlet of the crude acid separator 23 is connected to the solid alkali dryer 29 through a liquid level control. The middle outlet of the hydrochloric acid buffer tank 24 is connected to the hydrochloric acid storage tank 27 through the hydrochloric acid transfer pump 26, and the bottom outlet of the hydrochloric acid storage tank 27 is connected to the hydrochloric acid loading pump 28. The bottom outlet of the hydrochloric acid buffer tank 24 is connected back to the crude acid separator 23 through the organic matter recovery pump 25. The outlet of the solid alkali dryer 29 is connected to the crude chloride liquid storage tank 30.

[0053] Specifically, the absorbent liquid containing hydrogen chloride, discharged from the bottom outlet of the primary membrane absorber 201, enters the crude acid separator 23. The crude acid separator 23 utilizes the differences in density and solubility of different substances to separate hydrochloric acid and chloride in the absorbent liquid. After separation, the upper overflow outlet discharges relatively pure hydrochloric acid, which flows into the hydrochloric acid buffer tank 24 for temporary storage. The hydrochloric acid buffer tank 24 stabilizes the flow rate and pressure of the hydrochloric acid. Its middle outlet is pumped by the hydrochloric acid transfer pump 26 to the hydrochloric acid storage tank 27 for long-term storage. The hydrochloric acid loading pump 28 at the bottom outlet of the hydrochloric acid storage tank 27 facilitates loading and transportation of the hydrochloric acid. The liquid discharged from the bottom outlet of the hydrochloric acid buffer tank 24 may still contain a small amount of organic matter. This is recovered by the organic matter recovery pump 25, which connects it back to the crude acid separator 23 for further recovery of useful components. The chloride discharged from the bottom outlet of the crude acid separator 23 enters the solid alkali dryer 29 through liquid level control. In the solid alkali dryer 29, the chloride reacts with solid alkali to further remove moisture and other impurities. After drying, the chloride is discharged from the outlet of the solid alkali dryer 29 and connected to the crude chloride liquid storage tank 30 for storage, so as to carry out further processing or utilization.

[0054] This also includes: Azeotropic tower feed pump 35, the inlet of which is connected to crude chlorination liquid storage tank 30, and the outlet of which is connected to azeotropic tower 36. The bottom of the azeotropic tower 36 is equipped with an azeotropic tower reboiler 37, the top of the azeotropic tower 36 is equipped with an azeotropic tower top condenser 38, and the bottom outlet of the azeotropic tower 36 is connected back to the crude chlorination liquid storage tank 30 through the bottom outlet cooler 39. The alkaline washing separator 33 has its inlet connected to the material from the azeotropic tower 36, and its heavy phase outlet is circulated or discharged through the alkaline washing pump 34.

[0055] Specifically, after the azeotropic tower feed pump 35 starts, it precisely delivers the crude chlorinated liquid stored in the crude chlorinated liquid storage tank 30 to the azeotropic tower 36. As a key piece of equipment for achieving azeotropic distillation, the azeotropic tower 36, through a specific packing or tray structure, provides an ideal environment for sufficient contact and mass transfer between the gas and liquid phases. Inside the tower, the crude chlorinated liquid comes into countercurrent contact with the rising vapor, undergoing an azeotropic distillation reaction, thereby effectively separating components with different boiling points.

[0056] The reboiler 37 of the azeotropic column is located at the bottom of the azeotropic column 36. It provides the necessary heat to the column through an external heat source (such as steam or heat transfer oil) to maintain a certain temperature gradient within the column and ensure the continuous operation of the distillation process. The azeotropic column overhead condenser 38, located at the top of the column, uses a cooling medium (such as cooling water) to cool the rising vapor below the dew point, causing it to partially or completely condense into liquid. Part of the condensed liquid is returned to the azeotropic column 36 as reflux to regulate the temperature and composition within the column and improve separation efficiency; the other part is collected as the overhead product.

[0057] The azeotropic tower reboiler cooler 39 further cools the material discharged from the reboiler of the azeotropic tower 36, lowering its temperature for subsequent processing and storage. The cooled material is returned to the crude chlorination liquid storage tank 30 via pipeline, realizing the recycling of the material or its use as raw material in other processes.

[0058] The material collected from the top of the azeotropic tower 36 (mainly light components) can be directly output as a product or enter subsequent refining processes after necessary treatment; the material collected from the middle or side stream (mainly the target product or intermediate product) is transported to the alkaline washing separator 33 through pipelines. In the alkaline washing separator 33, these materials are thoroughly mixed and reacted with the added alkali solution to remove acidic impurities or other substances that can react with alkali. After the reaction, the mixture naturally separates into layers within the separator: the heavy phase (mainly the salts and other insoluble impurities generated in the reaction) settles at the bottom and is recycled by the alkaline washing pump 34 (such as for further separation or recovery of useful components) or directly discharged; the light phase (mainly the purified target product) is located at the top and is collected through the corresponding outlet for subsequent refining or storage processes.

[0059] This also includes: The crude chlorination liquid pump 31 has its inlet connected to the crude chlorination liquid storage tank 30 and its outlet connected to the feed inlet of the distillation column 40. The crude chlorination liquid in the crude chlorination liquid storage tank 30 is dried by self-circulation through the crude chlorination liquid dryer 32 to remove the water from the crude chlorination liquid. The bottom of the first distillation column 40 is equipped with a reboiler 41. The bottom liquid of the first distillation column 40 is sent to the second distillation column 47 through the bottom liquid pump 42. The top of the first distillation column 40 is equipped with a top condenser 43. The first distillation column dryer 44 and the first distillation column reflux tank 45 are connected in sequence to the outlet of the top condenser 43 of the first distillation column. The outlet of the first distillation column reflux tank 45 is divided into two paths by the first distillation column reflux pump 46. One path refluxes back to the top of the first distillation column 40, and the other path is connected to the light component storage tank 1. The bottom of the second distillation column 47 is equipped with a reboiler 48. The bottom liquid of the second distillation column 47 is discharged into the bottom liquid tank 50 of the second distillation column through the bottom liquid pump 49. The top of the second distillation column 47 is equipped with a top condenser 52. The second distillation column dryer 53 and the second distillation column reflux tank 54 are connected in sequence to the outlet of the top condenser 52 of the second distillation column. The outlet of the second distillation column reflux tank 54 is divided into two paths by the second distillation column reflux pump 55. One path refluxes back to the top of the second distillation column 47, and the other path is connected to the detection tank 56. The outlet of the testing tank 56 is equipped with a testing tank pump 57, which is used to pump qualified carbon tetrachloride products to the downstream refrigerant production unit. The outlet of the distillation column bottom liquid tank 50 is equipped with a distillation column bottom liquid tank transfer pump 51, which is used to send the bottom liquid residue to the incineration station.

[0060] Specifically, after the crude chlorination liquid pump 31 starts, it precisely delivers the crude chlorination liquid, which has undergone self-circulation drying treatment by the crude chlorination liquid dryer 32 and has had its moisture removed, from the crude chlorination liquid storage tank 30 to the feed inlet of the distillation column 40. As the key starting equipment for the entire distillation process, the distillation column 40, through its carefully designed packing or tray structure, provides an ideal environment for sufficient contact and efficient mass transfer between the gas and liquid phases. Inside the column, the crude chlorination liquid comes into countercurrent contact with the rising vapor, undergoing a distillation reaction, and achieving preliminary separation based on the differences in the boiling points of the components.

[0061] The reboiler 41 of the distillation column is located at the bottom of the distillation column 40. It uses an external heat source (such as steam or heat transfer oil) to continuously provide the required heat to the column, maintain a stable temperature gradient inside the column, and ensure that the distillation process can proceed uninterruptedly. The distillation column top condenser 43, located at the top of the column, uses a cooling medium (such as cooling water) to cool the rising vapor to below the dew point, causing some or all of the vapor to condense into liquid.

[0062] The condensate flowing from the outlet of the top condenser 43 of the distillation column passes sequentially through the dryer 44 and the reflux tank 45 of the distillation column. The dryer 44 further removes trace amounts of moisture from the condensate to ensure product purity; the reflux tank 45 stabilizes the flow rate and pressure. Subsequently, the liquid at the outlet of the reflux tank 45 is divided into two streams by the reflux pump 46. One stream returns to the top of the distillation column 40 as reflux liquid to precisely control the temperature and composition within the column and improve separation efficiency; the other stream is sent to the light component storage tank 1 for storage or further processing as a light component product.

[0063] The bottom liquid of distillation column 40 is sent to distillation column 47 via distillation column bottom liquid pump 42 for further separation. Distillation column 47 is also equipped with a distillation column reboiler 48 to provide heat to the column and maintain distillation conditions; a distillation column top condenser 52 is provided at the top of the column to condense the rising vapor.

[0064] The condensate flowing from the outlet of the top condenser 52 of the second distillation column passes sequentially through the dryer 53 and the reflux tank 54 of the second distillation column. The dryer 53 further purifies the condensate, while the reflux tank 54 stabilizes the system parameters. Afterward, the liquid at the outlet of the reflux tank 54 is divided into two paths by the reflux pump 55: one path flows back to the top of the second distillation column 47 to optimize the separation environment within the column; the other path connects to the detection tank 56.

[0065] The testing tank 56 conducts rigorous quality testing on the incoming liquid. Only carbon tetrachloride products that meet the standards are pumped through the testing tank pump 57 to the downstream refrigerant production unit for subsequent refrigerant synthesis. Meanwhile, the bottom liquid stored in the distillation column bottom liquid tank 50 is sent to the incineration station for harmless treatment via the distillation column bottom liquid tank transfer pump 51, ensuring that the entire production process is environmentally friendly and safe.

[0066] In summary, dichloromethane or trichloromethane is vaporized and superheated to 90°C and 0.6 MPa.G, and liquid chlorine is vaporized and superheated to 90°C and 1.2 MPa.G. These are then metered and mixed in a 1:3 volume ratio before entering mixer 11. The uniformly mixed raw material gas enters reflux device 12, where it is further mixed and diluted with reflux gas before being sent to reactor 13 (reaction conditions: 430-500°C, 0.05 MPa.G), primarily producing carbon tetrachloride and hydrogen chloride. The reaction gas from the chlorination reaction enters primary air cooler 161, where a portion of the cooled reaction gas is returned to reactor 13 as reflux gas; the remaining portion sequentially enters secondary air cooler 162, carbon black separator 17, and then tertiary condenser 28 and phase separator 19. The condensed and separated chlorides are sent to crude chlorination liquid storage tank 30. Uncondensed reaction gas enters the top of the primary membrane absorber 201, where dilute hydrochloric acid from the secondary membrane absorber 202 absorbs the hydrogen chloride and captures most of the chlorides. The gas treated by the primary membrane absorber 201 enters the top of the secondary membrane absorber 202, where dilute hydrochloric acid from the tail gas tower 21 further absorbs the hydrogen chloride and captures the remaining chlorides. The remaining gas enters the tail gas tower 21, where industrial water and some dilute hydrochloric acid circulating in the tower bottom are added to the top of the tower to absorb and capture hydrogen chloride and chlorides again. The inert gas exiting the tower (after being collected with the vent gas from various parts of the unit and the gas discharged from the safety valve) is sent to the external alkaline scrubbing system, where it is treated and then discharged to the incineration plant.

[0067] The liquid discharged from the bottom of the primary membrane absorber 201 enters the crude acid separator 23. Hydrochloric acid flows from the upper overflow pipe into the hydrochloric acid buffer tank 24. The hydrochloric acid in the middle of the buffer tank is sent to the hydrochloric acid storage tank 27 in the tank area by the hydrochloric acid transfer pump 26. The organic matter at the bottom is recovered to the crude acid separator 23 by the organic matter recovery pump 25. The chloride at the bottom of the crude acid separator 23 enters the solid alkali dryer 29 through the liquid level control. The dried chloride is sent to the crude chloride liquid storage tank 30. The crude chlorination liquid first enters the azeotropic system to remove free acid and water, then returns to the crude chlorination liquid storage tank 30, and is subsequently sent to the first distillation column 40 via the crude chlorination liquid pump 31. The light components separated at the top of the column are condensed and dried, with part of them returning to the column as reflux liquid and the remainder being sent to the light components storage tank 1. The bottom liquid enters the second distillation column 47, where the components separated at the top of the column are condensed and dried, with part of them returning to the column as reflux liquid and the remainder being sent to the testing tank 56 as feed liquid. After passing the test, the feed liquid is pumped to the new refrigerant production unit. The bottom liquid enters the bottom liquid tank 50 of the second distillation column and is then sent to the incineration station via the bottom liquid tank transfer pump 51.

[0068] Example 2: Based on Example 1, the present invention provides a method for preparing high-purity carbon tetrachloride, comprising the following steps: S1. Raw material pretreatment: Dichloromethane and / or trichloromethane are vaporized and superheated to approximately 90°C and 0.6 MPa.G in light component evaporator 4 and light component superheater 5; liquid chlorine is vaporized and superheated to approximately 90°C and 1.2 MPa.G in liquid chlorine vaporizer 8 and chlorine superheater 10; the two are then transported to mixer 11 for mixing at a volume ratio of 1:2-4. S2, Chlorination reaction: The mixed raw material gas from step S1 is mixed and diluted with the reflux gas from the first-stage air cooler 161 via the reflux device 12, and then sent to the reactor 13 to carry out the chlorination reaction at 430℃-450℃ and 0.05MPa.G to generate a reaction gas containing carbon tetrachloride and hydrogen chloride. S3. Separation and purification of reaction gas: The reaction gas from step S2 is cooled sequentially by a primary air cooler 161 and a secondary air cooler 162, and after carbon black is removed by a carbon black separator 17, it enters a tertiary condenser 18 for condensation. Gas-liquid separation is carried out in a phase separator 19 to obtain crude chlorination liquid. The uncondensed gas is sequentially absorbed by a primary membrane absorber 201, a secondary membrane absorber 202, and a tail gas tower 21 to absorb hydrogen chloride and capture residual chlorides. After purification, the tail gas is discharged. S4. Refining of crude chlorinated liquid: The crude chlorinated liquid obtained in step S3 is subjected to azeotropic dehydration and deacidification, light components are separated in distillation column 40, and purified by distillation in distillation column 47 to finally obtain carbon tetrachloride product with a purity of not less than 99.99 wt%.

[0069] Specifically, in the raw material pretreatment step S1, dichloromethane and / or trichloromethane undergo a liquid-gas phase change in the light component evaporator 4, and then enter the light component superheater 5 for further heating to a superheated vapor state of approximately 90°C and 0.6 MPa.G, creating favorable conditions for subsequent thorough mixing and reaction with chlorine. Simultaneously, liquid chlorine is rapidly vaporized in the liquid chlorine vaporizer 8, and then heated to a superheated chlorine state at the same temperature but a higher pressure (approximately 90°C and 1.2 MPa.G) by the chlorine superheater 10. The higher pressure helps to improve the activity and reaction efficiency of chlorine. The two are then uniformly mixed in the mixer 11 according to a precisely calculated 1:3 volume ratio to form a raw material gas suitable for the chlorination reaction.

[0070] After entering the chlorination reaction step S2, the mixed feed gas is first mixed with the reflux gas from the primary air cooler 161 through the reflux device 12. This process dilutes the concentration of the feed gas and adjusts its temperature and pressure to better match the reaction conditions within reactor 13. In reactor 13, the feed gas undergoes a vigorous chlorination reaction under high temperature conditions of 430℃-450℃ and low pressure conditions of 0.05MPa.G, generating a reaction gas with carbon tetrachloride and hydrogen chloride as the main components.

[0071] The reaction gas separation and purification step S3 then commences. The reaction gas is first continuously cooled by a primary air cooler 161 and a secondary air cooler 162, resulting in a rapid temperature drop to facilitate subsequent separation operations. The gas then enters a carbon black separator 17, effectively removing solid impurities such as carbon black that may be generated during the reaction, ensuring the purity of subsequent separation processes. Next, the gas enters a tertiary condenser 18 for deep condensation, where most of the high-boiling-point components are condensed into liquids. These liquids then enter a phase separator 19 to complete gas-liquid separation, separating crude chlorinated liquid. The uncondensed gas continues its journey, passing sequentially through a primary membrane absorber 201, a secondary membrane absorber 202, and a tail gas tower 21. Through absorption and capture, hydrogen chloride and residual chlorides are thoroughly removed, ensuring that the exhaust gas meets environmental standards.

[0072] Finally, the crude chlorinated liquid enters the refining step S4. The crude chlorinated liquid obtained in step S3 is first subjected to azeotropic dehydration and deacidification treatment to remove water and acidic impurities, providing a purer raw material for subsequent distillation. Subsequently, the crude chlorinated liquid is sent to distillation column 40, where light components (which may contain unreacted raw materials or other low-boiling-point impurities) are separated by distillation. The bottom liquid of distillation column 40 after preliminary separation is then sent to distillation column 47 for further distillation and purification. By precisely controlling the distillation conditions, carbon tetrachloride product with a purity of not less than 99.99 wt% is finally obtained.

[0073] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A novel energy-saving and environmentally friendly refrigerant raw material preparation system, characterized in that, It includes a raw material preparation and supply unit, a reaction and separation unit, and a purification unit connected in sequence; The raw material preparation and supply unit is used to vaporize and superheat dichloromethane and / or trichloromethane with liquid chlorine respectively, and mix them in proportion to form raw material gas; The reaction and separation unit includes a mixer (11), a reflux device (12), a reactor (13), a cooling and separation device, a membrane absorption device, and a tail gas tower (21) connected in sequence. It is used to make the raw material gas undergo a chlorination reaction to generate a reaction gas containing carbon tetrachloride, and to cool, separate the gas and liquid, absorb hydrogen chloride, and purify the tail gas. The refining unit includes an azeotropic tower (36), a first distillation tower (40), and a second distillation tower (47) connected in sequence, which are used to dehydrate, deacidify, and purify the separated crude chlorinated liquid by distillation to obtain a high-purity carbon tetrachloride product.

2. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 1, characterized in that: The raw material preparation and supply unit includes a light component processing subsystem and a chlorine processing subsystem; The light component processing subsystem includes a light component storage tank (1), a light component receiving tank (3), a light component evaporator (4), and a light component superheater (5) connected in sequence, for vaporizing and superheating dichloromethane and / or trichloromethane to about 90°C and 0.6 MPa.G; The chlorine treatment subsystem includes a liquid chlorine storage tank (6), a liquid chlorine vaporizer (8), and a chlorine superheater (10) connected in sequence, for vaporizing and superheating the liquid chlorine to about 90°C and 1.2 MPa.G; The outlets of the light component superheater (5) and the chlorine superheater (10) are both connected to the mixer (11).

3. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 2, characterized in that: The light component storage tank (1) is used to store dichloromethane and / or trichloromethane, and a light component pump (2) is provided on the pipeline between the light component storage tank (1) and the light component receiving tank (3). The outlet at the bottom of the light component receiving tank (3) is connected to the inlet of the light component evaporator (4) through a pipeline. The light component evaporator (4) is used to vaporize dichloromethane and / or trichloromethane. The vaporized dichloromethane and / or trichloromethane are returned to the light component receiving tank (3). The outlet at the top of the light component receiving tank (3) is connected to the inlet of the light component superheater (5) by a pipeline. The vaporized dichloromethane and / or trichloromethane that flows back to the light component receiving tank (3) flows into the light component superheater (5). The light component superheater (5) is used to superheat the vaporized dichloromethane and / or trichloromethane to about 90°C and 0.6 MPa.G.

4. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 2, characterized in that: The liquid chlorine storage tank (6) is used to store liquid chlorine, and a liquid chlorine pump (7) is provided on the pipeline between the liquid chlorine storage tank (6) and the liquid chlorine vaporizer (8). A chlorine buffer tank (9) is provided on the pipeline between the liquid chlorine vaporizer (8) and the chlorine superheater (10); The liquid chlorine vaporizer (8) is used to vaporize liquid chlorine, and after vaporization, chlorine gas is formed and stored in the chlorine buffer tank (9). The chlorine gas in the chlorine buffer tank (9) flows to the chlorine superheater (10), which is used to superheat the chlorine gas to about 90°C and 1.2 MPa.G.

5. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 1, characterized in that: The reactor (13) is equipped with a reactor electric heater (14), and the operating temperature of the reactor (13) is 430℃-450℃ and the operating pressure is 0.05MPa.G; The top outlet of the reactor (13) is connected to a release tank (15), which serves as a buffer space for pressure relief. The cooling separation device includes a primary air cooler (161), a secondary air cooler (162), a carbon black separator (17), a tertiary condenser (18), and a phase separator (19) connected in sequence. The inlet of the primary air cooler (161) is connected to the outlet of the reactor (13). The outlet of the primary air cooler (161) is divided into two paths. One path is connected to the reflux device (12) through a pipeline to provide reflux gas, and the other path is connected in sequence to the secondary air cooler (162), carbon black separator (17), tertiary condenser (18) and phase separator (19). The liquid outlet of the phase separator (19) is connected to the crude chlorination liquid storage tank (30), and the gas outlet is connected to the membrane absorption device.

6. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 5, characterized in that: The membrane absorption device includes a primary membrane absorber (201) and a secondary membrane absorber (202) connected in series. The top air inlet of the first-stage membrane absorber (201) is connected to the gas outlet of the phase separator (19), the bottom liquid outlet of the first-stage membrane absorber (201) is connected to the crude acid separator (23), and the absorbent inlet of the first-stage membrane absorber (201) is connected to the bottom dilute acid outlet of the second-stage membrane absorber (202). The top air inlet of the secondary membrane absorber (202) is connected to the top air outlet of the primary membrane absorber (20), and the absorbent inlet of the secondary membrane absorber (202) is connected to the circulating acid outlet of the tail gas tower (21). The inlet of the tail gas tower (21) is connected to the top outlet of the secondary membrane absorber (202). The top of the tail gas tower (21) is provided with an industrial water inlet and a circulating acid inlet. The bottom outlet of the tail gas tower (21) is partially circulated back into the tower through the tail gas tower circulation pump (22). The top outlet of the tail gas tower (21) is connected to the external alkaline washing and incineration system.

7. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 6, characterized in that: The bottom outlet of the primary membrane absorber (201) is connected to a crude acid separator (23), which is used to separate and recover hydrochloric acid and chloride. The overflow port at the top of the crude acid separator (23) is connected to the hydrochloric acid buffer tank (24), and the bottom outlet of the crude acid separator (23) is connected to the solid alkali dryer (29) through liquid level control. The middle outlet of the hydrochloric acid buffer tank (24) is connected to the hydrochloric acid storage tank (27) via the hydrochloric acid transfer pump (26), the bottom outlet of the hydrochloric acid storage tank (27) is connected to the hydrochloric acid loading pump (28), and the bottom outlet of the hydrochloric acid buffer tank (24) is connected back to the crude acid separator (23) via the organic matter recovery pump (25). The outlet of the solid alkali dryer (29) is connected to the crude chlorination liquid storage tank (30).

8. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 7, characterized in that, Also includes: An azeotropic tower feed pump (35) is provided, with its inlet connected to a crude chlorination liquid storage tank (30) and its outlet connected to an azeotropic tower (36). The bottom of the azeotropic tower (36) is provided with an azeotropic tower reboiler (37), the top of the azeotropic tower (36) is provided with an azeotropic tower top condenser (38), and the bottom outlet of the azeotropic tower (36) is connected back to the crude chlorination liquid storage tank (30) through the bottom outlet cooler (39). Alkali washing separator (33) is connected to the material from the azeotropic tower (36) at its inlet, and the heavy phase outlet of the alkali washing separator (33) is circulated or discharged through the alkali washing pump (34).

9. The novel energy-saving and environmentally friendly refrigerant raw material preparation system according to claim 8, characterized in that, Also includes: A crude chlorination liquid pump (31) is connected to a crude chlorination liquid storage tank (30) at its inlet and to a distillation column (40) at its outlet. The crude chlorination liquid in the crude chlorination liquid storage tank (30) is dried by a crude chlorination liquid dryer (32) through self-circulation to remove moisture from the crude chlorination liquid. The bottom of the first distillation column (40) is provided with a reboiler (41), the bottom liquid of the first distillation column (40) is sent to the second distillation column (47) through the bottom liquid pump (42), and the top of the first distillation column (40) is provided with a top condenser (43). The first distillation column dryer (44) and the first distillation column reflux tank (45) are connected in sequence to the outlet of the top condenser (43) of the first distillation column. The outlet of the first distillation column reflux tank (45) is divided into two paths by the first distillation column reflux pump (46). One path refluxes back to the top of the first distillation column (40), and the other path is connected to the light component storage tank (1). The bottom of the distillation column (47) is provided with a distillation column reboiler (48), the bottom liquid of the distillation column (47) is discharged into the bottom liquid tank (50) of the distillation column through the bottom liquid pump (49), and the top of the distillation column (47) is provided with a distillation column top condenser (52). The second distillation column dryer (53) and the second distillation column reflux tank (54) are connected in sequence to the outlet of the top condenser (52) of the second distillation column. The outlet of the second distillation column reflux tank (54) is divided into two paths by the second distillation column reflux pump (55). One path flows back to the top of the second distillation column (47), and the other path is connected to the detection tank (56). The outlet of the testing tank (56) is equipped with a testing tank pump (57) for pumping qualified carbon tetrachloride products to the downstream refrigerant production unit. The outlet of the distillation column bottom liquid tank (50) is equipped with a distillation column bottom liquid tank transfer pump (51) for sending the bottom liquid to the incineration station.

10. A method for preparing high-purity carbon tetrachloride using a novel energy-saving and environmentally friendly refrigerant raw material preparation system according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Raw material pretreatment: Dichloromethane and / or trichloromethane are vaporized and superheated to about 90°C and 0.6 MPa.G in a light component evaporator (4) and a light component superheater (5); liquid chlorine is vaporized and superheated to about 90°C and 1.2 MPa.G in a liquid chlorine vaporizer (8) and a chlorine superheater (10); the two are transported to a mixer (11) for mixing at a volume ratio of 1:2-4. S2, Chlorination reaction: The mixed raw material gas from step S1 is mixed and diluted with the reflux gas from the first-stage air cooler (161) via the reflux device (12), and then sent to the reactor (13) to carry out the chlorination reaction at 430℃-450℃ and 0.05MPa.G to generate a reaction gas containing carbon tetrachloride and hydrogen chloride. S3. Separation and purification of reaction gas: The reaction gas from step S2 is cooled sequentially by a primary air cooler (161) and a secondary air cooler (162), and after carbon black is removed by a carbon black separator (17), it enters a tertiary condenser (18) for condensation. Gas-liquid separation is carried out in a phase separator (19) to obtain crude chlorination liquid. The uncondensed gas is sequentially absorbed by a primary membrane absorber (201), a secondary membrane absorber (202) and a tail gas tower (21) to absorb hydrogen chloride and capture residual chloride. After purification, the tail gas is discharged. S4. Refining of crude chlorinated liquid: The crude chlorinated liquid obtained in step S3 is subjected to azeotropic dehydration and deacidification, light components are separated in distillation column 1 (40), and purified by distillation in distillation column 2 (47) to finally obtain carbon tetrachloride product with a purity of not less than 99.99 wt%.

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