Vinyl chloride production system adopting coal-based ethylene method

Abstract

The utility model belongs to the technical field of chemical engineering, and particularly relates to a vinyl chloride production system by a coal-based ethylene method. Comprising an ethanol dehydration reaction system, a quenching compression and evaporation system, a water alkali washing system, an adsorber system, a low-temperature rectification system, a high-low temperature chlorination system, a dichloroethane cracking system and a propylene refrigeration cycle system, wherein the low-temperature rectification system comprises a demethanizer, a purification tower and a low-temperature rectification refrigeration device; the high-low temperature chlorination system comprises a high-low temperature chlorination reactor and a high-low temperature chlorination refrigeration device; the dichloroethane cracking system comprises a cracking device and a cracking refrigeration device; the propylene refrigeration cycle system is respectively connected with the low-temperature rectification refrigeration device, the high-low temperature chlorination refrigeration device and the cracking refrigeration device and respectively provides heat and cold for the three systems. By adopting the propylene refrigeration cycle system, a refrigerant can be reasonably distributed, long-time, safe and stable full-load operation of a vinyl chloride production system by a coal-based ethylene method is ensured, the stability is high, and the temperature adjusting range is wide.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a coal-based ethylene process for vinyl chloride production. Background Technology

[0002] Vinyl chloride (VCM) is an important monomer for the synthesis of polyvinyl chloride (PVC), which is the world's second largest general-purpose synthetic resin material and my country's largest general-purpose synthetic resin material, widely used in various fields such as industry, agriculture, and construction.

[0003] Currently, there are two main methods for producing vinyl chloride: the acetylene method (calcium carbide method) and the ethylene method. The acetylene method, due to the large amount of calcium carbide slag produced during its production and the high energy consumption required for the production of its raw material, calcium carbide (approximately 3500 kWh / t calcium carbide), has become a key target for rectification. On March 7, 2022, the Ministry of Ecology and Environment issued the "Opinions on Further Strengthening the Prevention and Control of Heavy Metal Pollution," requiring a ban on the construction of new acetylene method vinyl chloride production processes using mercury. The "Draft for Comments on the Guidance Catalogue for Industrial Structure Adjustment (2023 Edition)" lists acetylene method vinyl chloride production facilities using high-mercury catalysts as outdated and prohibited processes, and lists acetylene method vinyl chloride as outdated and restricted processes. Internationally, the ethylene method accounts for 70% of vinyl chloride production, while in China it accounts for only 23%. Given the increasingly stringent energy conservation, emission reduction, and environmental pressures in China, adopting the ethylene method for vinyl chloride production is an inevitable trend.

[0004] The ethylene process boasts a wide range of raw material sources, high product quality, large production scale, rational resource allocation, low production costs, easily controllable environmental pollution, and low energy consumption. With the deepening of green manufacturing, its green, environmentally friendly, and sustainable nature has garnered support, which will facilitate the accelerated large-scale development of the ethylene process. Simultaneously, with the technological advancements in my country's coal chemical industry, the production of ethylene from coal is gradually becoming an emerging industry.

[0005] The coal-based ethylene-based vinyl chloride production system includes an ethanol dehydration reaction system, a quenching compression and evaporation system, a water-alkali washing system, an adsorber system, an ethylene cryogenic distillation system, an ethylene high- and low-temperature chlorination system, a dichloroethane (EDC) cracking system, and a refrigeration system. The refrigeration system plays a crucial role in the coal-based ethylene-based vinyl chloride production process. First, several reaction steps in the production process have strict temperature requirements. For example, in the ethylene chlorination reaction, the appropriate temperature is a key factor in ensuring the reaction rate and selectivity. The refrigeration system can precisely control the reaction temperature, preventing excessively high temperatures from increasing side reactions or excessively low temperatures from slowing the reaction rate. It can remove excess heat generated during the reaction, allowing the reaction to proceed within the optimal temperature range, thereby improving the yield and quality of vinyl chloride. Second, the entire production process involves the handling and transportation of various materials. Some materials, such as ethylene, need to be stored or transported at low temperatures. The refrigeration system can cool ethylene to a suitable temperature, keeping it liquid for easy storage and precise metering and transportation. This is crucial for ensuring a stable supply and accurate proportioning of materials during production. Third, the refrigeration system helps control product quality. For vinyl chloride products, cooling can remove impurities and non-condensable gases. In the refining process of vinyl chloride, a suitable cooling temperature can bring the product to the required purity standard. At the same time, a stable refrigeration system ensures the continuity of the production process, reduces production interruptions caused by factors such as temperature fluctuations, and improves production efficiency.

[0006] Chinese patent CN113045372B discloses a process and apparatus for producing ethylene from ethanol through dehydration. The apparatus includes an ethanol dehydration reaction system, a quenching and compression system, an alkaline washing tower system, a molecular sieve regeneration system, an ethylene purification system, and a propylene refrigeration cycle system. The process involves sending ethanol to the ethanol dehydration system, where it undergoes a dehydration reaction to obtain reaction gas; cooling and separating the reaction gas in the quenching and compression system, and returning the recovered ethanol to the ethanol dehydration reaction system; sending crude ethylene, carbon dioxide, and water to the alkaline washing and molecular sieve system to remove carbon dioxide and water, obtaining crude ethylene; sending the crude ethylene to the ethylene purification system to obtain the ethylene product; and using the propylene refrigeration cycle system to provide cooling to the ethylene purification system. From the claims and description of this patent, it can be seen that the propylene refrigeration cycle system step is limited to the heat utilization of the ethylene purification section, and it uses a two-stage compressor, resulting in high energy consumption, a large footprint, and high production costs during operation.

[0007] Existing literature and patents have not reported on the supplementation and utilization of global heat in coal-based ethylene chloride production. Furthermore, due to load variations and ambient temperature fluctuations during coal-based ethylene chloride production, temperature control of the refrigeration system is challenging, easily leading to excessively high or low temperatures, improper refrigerant distribution, and poor system operational stability. This results in significant ethylene loss and negatively impacts the production quality and efficiency of vinyl chloride. Therefore, providing a coal-based ethylene chloride production system that comprehensively considers global heat utilization and offers stable, safe, and reliable operation is of paramount importance. Summary of the Invention

[0008] In order to overcome the shortcomings of the existing technology, this utility model provides a coal-based ethylene method for producing vinyl chloride.

[0009] To achieve the above objectives, the technical solution of this utility model is as follows: A coal-based ethylene-based vinyl chloride production system, comprising an ethanol dehydration reaction system 1, a quenching compression and evaporation system 2, a water-alkali washing system 3, an adsorber system 4, a low-temperature distillation system 5, a high-low temperature chlorination system 6, a dichloroethane cracking system 7, and a propylene refrigeration cycle system 8, characterized in that: the low-temperature distillation system 5 includes a demethanizer, a purification tower, and a low-temperature distillation refrigeration device; the high-low temperature chlorination system 6 includes a high-low temperature chlorination reactor and a high-low temperature chlorination refrigeration device; the dichloroethane cracking system 7 includes a cracking device and a cracking refrigeration device; the propylene refrigeration cycle system 8 is connected to the low-temperature distillation refrigeration device, the high-low temperature chlorination refrigeration device, and the cracking refrigeration device respectively. High-temperature gaseous propylene is transported to the low-temperature distillation system 5 for heat exchange through the propylene refrigeration cycle system 8, and then returned to the propylene refrigeration cycle system 8 for recycling; simultaneously, low-temperature liquid propylene is transported to the high-low temperature chlorination system 6 and the dichloroethane cracking system 7 for heat exchange through the propylene refrigeration cycle system 8, and then returned to the propylene refrigeration cycle system 8 for recycling.

[0010] The coal-based ethylene-based vinyl chloride production system includes a propylene refrigeration cycle system 8 comprising a propylene compressor 805, a condenser 802, a high-temperature flash economizer 803, a low-temperature flash economizer 806, a subcooler A808, a suction buffer tank 807, a bypass suction buffer tank 804, and a subcooler B801. The outlet pipe of the propylene compressor 805 is divided into two branches: one connected to a low-temperature distillation refrigeration unit, and the other connected to the condenser 802. The outlet of the condenser 802 is also divided into two branches: one connected to the high-temperature flash economizer 803, and the other connected to the bypass suction buffer tank 804. 04. The outlet pipe of the bypass suction buffer tank 804 is connected to the propylene compressor 805; the high-temperature flash economizer 803 is connected to the low-temperature flash economizer 806; the outlet of the low-temperature flash economizer 806 is divided into two paths, one connected to the propylene compressor 805 and the other connected to the subcooler A808; the outlet pipe of the subcooler A808 is divided into two paths, one connected to the propylene compressor 805 and the other connected to the high and low temperature chlorination refrigeration unit, the dichloroethane cracking refrigeration unit, and the suction buffer tank 807 respectively; the suction buffer tank 807 is connected to the propylene compressor 805.

[0011] The coal-based ethylene chloride production system includes a cryogenic distillation and refrigeration unit comprising a purification tower reboiler (509), a demethanizer reboiler (508), an ethylene heater (507), a propylene condenser (506), a propylene collection tank (505), a primary flash tank (504), a secondary flash tank (503), a purification tower condenser (502), and an ethylene cryocooler (501). One outlet pipe of the propylene compressor (805) is connected to the purification tower reboiler (509), the demethanizer reboiler (508), the ethylene heater (507), and the propylene condenser (506). The outlets of the purification tower reboiler (509), the demethanizer reboiler (509), the ethylene heater (507), and the propylene condenser (506) are connected to the propylene collection tank. Tank 505; the propylene collection tank 505 is connected to the first-stage flash tank 504; the outlet pipe of the first-stage flash tank 504 is divided into two paths, one connected to the propylene compressor 805, and the other connected to the second-stage flash tank 503; the outlet of the second-stage flash tank 503 is divided into two paths, one connected to the propylene compressor 805, and the other connected to the subcooler B801; the outlet of the subcooler B801 is divided into two paths, one connected to the propylene compressor 805, and the other connected to the purification tower condenser 502 and the ethylene cryocooler 501 respectively; the outlet pipe of the purification tower condenser 502 is connected to the suction buffer tank 807; the outlet pipe of the ethylene cryocooler 501 is connected to the suction buffer tank 807.

[0012] The coal-based ethylene process for vinyl chloride production includes a high- and low-temperature chlorination refrigeration unit comprising a high-temperature chlorination liquid ring compressor 604, a low-temperature chlorination reactor exhaust condenser 603, a high-temperature chlorination exhaust condenser 602, and a high-temperature exhaust gas cooler 601. One of the outlet pipes of the subcooler A808 is connected to the high-temperature chlorination liquid ring compressor 604, the low-temperature chlorination reactor exhaust condenser 603, the high-temperature chlorination exhaust condenser 602, and the high-temperature exhaust gas cooler 601, respectively. The outlet pipes of the high-temperature chlorination liquid ring compressor 604, the low-temperature chlorination reactor exhaust condenser 603, the high-temperature chlorination exhaust condenser 602, and the high-temperature exhaust gas cooler 601 are connected to the suction buffer tank 807.

[0013] The coal-based ethylene chloride production system includes a cracking refrigeration unit comprising a cracking hydrogen chloride condenser 701; one branch of the outlet pipe of the subcooler A808 is connected to the cracking hydrogen chloride condenser 701, and the outlet pipe of the cracking hydrogen chloride condenser 701 is connected to the suction buffer tank 807.

[0014] The coal-based ethylene chloride production system described herein uses a multi-stage centrifugal propylene compressor 805.

[0015] The coal-based ethylene process for vinyl chloride production is equipped with a PLC automatic control system.

[0016] The beneficial effects of this utility model are as follows: By setting up a propylene refrigeration cycle system, the refrigerant can be rationally distributed. It can not only supply gaseous propylene at a temperature of 80-90℃ to the ethanol dehydration unit, but also supply liquid propylene at a temperature of -15~-25℃ to the vinyl chloride unit. This ensures long-term, safe, stable, and full-load operation of the coal-based ethylene vinyl chloride production system. It also has strong stability and a wide temperature adjustment range, effectively avoiding cost increases and product quality declines caused by starting and stopping the refrigeration system. In addition, it has a small footprint, which can significantly reduce equipment investment, lower fixed costs, and achieve a high return on investment. Attached Figure Description

[0017] Figure 1 This is a flowchart of the production system of this utility model.

[0018] Figure 2 This is a schematic diagram of the propylene refrigeration cycle system in this utility model.

[0019] Figure 1-2In the diagram, 1 is the ethanol dehydration reaction system, 2 is the quenching compression and evaporation system, 3 is the water-alkali washing system, 4 is the adsorber system, 5 is the low-temperature distillation system, 6 is the high- and low-temperature chlorination system, 7 is the dichloroethane cracking system, and 8 is the propylene refrigeration cycle system; 501 is the ethylene cryostat, 502 is the purification condenser, 503 is the secondary flash tank, 504 is the primary flash tank, 505 is the propylene collection tank, 506 is the propylene condenser, 507 is the ethylene heater, 508 is the demethanizer reboiler, and 509 is the purification tower reboiler; 701 is the cracked hydrogen chloride condenser, and 60... 1 is a high-temperature exhaust gas cooler, 602 is a high-temperature chlorination exhaust gas condenser, 603 is a low-temperature chlorination reactor exhaust gas condenser, and 604 is a high-temperature chlorination liquid ring compressor; 801 is subcooler B, 802 is a condenser, 803 is a high-temperature flash economizer, 804 is a bypass suction buffer tank, 805 is a propylene compressor, 806 is a low-temperature flash economizer, 807 is a suction buffer tank, and 808 is subcooler A; a is ethanol, b is reaction gas, c is dilution vapor, d is crude ethylene, e is product ethylene, f is dichloroethane, g is vinyl chloride, and h is hydrogen chloride. Detailed Implementation

[0020] Example 1: Refer to Appendix Figure 1 This embodiment relates to a coal-based ethylene process for producing vinyl chloride, comprising an ethanol dehydration reaction system 1, a quenching compression and evaporation system 2, a water-alkali washing system 3, an adsorber system 4, a low-temperature distillation system 5, a high-low temperature chlorination system 6, a dichloroethane cracking system 7, and a propylene refrigeration cycle system 8. The propylene refrigeration cycle system 8 provides heat and cooling to the low-temperature distillation system 5, the high-low temperature chlorination system 6, and the dichloroethane cracking system 7. High-temperature gaseous propylene is transported to the low-temperature distillation system 5 for heat exchange via the propylene refrigeration cycle system 8, and then returned to the propylene refrigeration cycle system 8 for recycling. Simultaneously, low-temperature liquid propylene is transported to the high-low temperature chlorination system 6 and the dichloroethane cracking system 7 for heat exchange via the propylene refrigeration cycle system 8, and then returned to the propylene refrigeration cycle system 8 for recycling.

[0021] Example 2: Refer to Appendix Figure 1 and attached Figure 2The difference in this embodiment lies in that the coal-based ethylene process for producing vinyl chloride includes a cryogenic distillation system 5 comprising a demethanizer, a purification tower, and a cryogenic distillation refrigeration unit. The cryogenic distillation refrigeration unit includes a purification tower reboiler 509, a demethanizer reboiler 508, an ethylene heater 507, a propylene condenser 506, a propylene collection tank 505, a primary flash tank 504, a secondary flash tank 503, a purification tower condenser 502, and an ethylene cryocooler 501. High-temperature gaseous propylene from the propylene refrigeration cycle system 8 is supplied with heat to the purification tower reboiler 509, the demethanizer reboiler 508, the ethylene heater 507, and the propylene condenser 506. The propylene condensate produced by the reboiler 509 of the purification tower, the reboiler 508 of the demethanizer tower, the ethylene heater 507, and the propylene condenser 506 enters the propylene collection tank 505. The high-temperature liquid propylene in the propylene collection tank 505 is then cooled by flash evaporation in the first-stage flash tank 504 and the second-stage flash tank 503. The gaseous propylene flashed out by the first-stage flash tank 504 and the second-stage flash tank 503 is returned to the propylene refrigeration cycle system 8. The low-temperature liquid propylene obtained by the second-stage flash tank 503 is transported to the purification tower condenser 502 and the ethylene cryocooler 501 as a cold source. The low-pressure gaseous ethylene produced by the purification tower condenser 502 and the ethylene cryocooler 501 is returned to the propylene refrigeration cycle system 8.

[0022] Example 3: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment is that the coal-based ethylene method for producing vinyl chloride includes a dichloroethane cracking system 6 comprising a cracking device and a cracking refrigeration device; the cracking refrigeration device includes a cracking hydrogen chloride condenser 701; the low-temperature liquid propylene transported by the propylene refrigeration cycle system 8 is sent to the cracking hydrogen chloride condenser 701 for heat exchange and is then vaporized, and the resulting gaseous propylene is returned to the propylene refrigeration cycle system 8.

[0023] Example 4: Refer to Appendix Figure 1 and attached Figure 2The difference in this embodiment lies in that the coal-based ethylene method for producing vinyl chloride includes a propylene refrigeration cycle system 8 comprising a propylene compressor 805, a condenser 802, a high-temperature flash economizer 803, a low-temperature flash economizer 806, a subcooler A 808, a suction buffer tank 807, a bypass suction buffer tank 804, and a subcooler B 801. A portion of the gaseous propylene supplied by the propylene compressor enters the low-temperature distillation refrigeration unit for circulating heat exchange, while the remaining gaseous propylene enters the condenser 802 and is condensed into liquid propylene. A portion of the liquid propylene exiting the condenser 802 passes through the bypass suction buffer tank 804, becomes gas again, and returns to the propylene compressor 805. The remaining portion flashes through the high-temperature flash economizer 803 and then enters the low-temperature flash economizer 806. In the low-temperature flash economizer 806, a portion of the liquid propylene is flashed into liquid propylene. The vapor phase returns to 805, while the other portion of the liquid propylene is cooled and throttled before entering subcooler A808. In subcooler A808, a portion of the liquid propylene is flashed back into vapor and returned to propylene compressor 805, while the other portion is cooled and sent to the high and low temperature chlorination refrigeration unit, the cracking refrigeration unit, and the suction buffer tank 807. The low temperature liquid propylene evaporates into vapor after heat exchange in the high and low temperature chlorination refrigeration unit and the cracking refrigeration unit, and then returns to propylene compressor 805 for recycling after passing through suction buffer tank 807. The liquid propylene from the secondary flash tank 503 passes through cooler B801, where a portion of the liquid propylene is flashed back into vapor and returned to propylene compressor 805, while the other portion is cooled and sent to purification tower condenser 502 and ethylene cryocooler 501 as a refrigerant before evaporating back into vapor and returning to propylene compressor 805 for recycling.

[0024] Example 5: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment is that the propylene compressor in the coal-based ethylene method for producing vinyl chloride is a multi-stage centrifugal propylene compressor.

[0025] Example 6: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment is that, in the coal-based ethylene method for producing vinyl chloride, the high-temperature gaseous propylene delivered by the propylene compressor 805 to the low-temperature distillation refrigeration unit has a pressure of 1.75 MPa and a temperature of 90°C; the liquid-phase propylene delivered by the propylene compressor 805 to the high-low temperature chlorination refrigeration unit via the condenser 802, the high-temperature flash economizer 803, the low-temperature flash economizer 806, and the subcooler A808 has a pressure of 1.85 MPa and a temperature of -15°C.

[0026] Example 7: Refer to Appendix Figure 1 and attached Figure 2In the coal-based ethylene method for producing vinyl chloride described in this embodiment, the high-temperature gaseous propylene delivered by the propylene compressor 805 to the low-temperature distillation refrigeration unit has a pressure of 1.79 MPa and a temperature of 88°C. The liquid-phase propylene delivered by the propylene compressor 805 to the high-low temperature chlorination refrigeration unit via the condenser 802, the high-temperature flash economizer 803, the low-temperature flash economizer 806, and the subcooler A808 has a pressure of 1.82 MPa and a temperature of -20°C.

[0027] Example 8: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment is that, in the coal-based ethylene method for producing vinyl chloride, the high-temperature gaseous propylene delivered by the propylene compressor 805 to the low-temperature distillation refrigeration unit has a pressure of 1.82 MPa and a temperature of 85°C; the liquid-phase propylene delivered by the propylene compressor 805 to the high-low temperature chlorination refrigeration unit via the condenser 802, the high-temperature flash economizer 803, the low-temperature flash economizer 806, and the subcooler A808 has a pressure of 1.79 MPa and a temperature of -19°C.

[0028] Example 9: Refer to Appendix Figure 1 and attached Figure 2 In the coal-based ethylene method for producing vinyl chloride described in this embodiment, the high-temperature gaseous propylene supplied by the propylene compressor 805 to the low-temperature distillation refrigeration unit has a pressure of 1.85 MPa and a temperature of 80°C. The propylene compressor 805 then supplies liquid-phase propylene to the high-low temperature chlorination refrigeration unit via condenser 802, high-temperature flash economizer 803, low-temperature flash economizer 806, and subcooler A808, with a pressure of 1.75 MPa and a temperature of -25°C.

[0029] Example 10: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment lies in the following: in the coal-based ethylene process for producing vinyl chloride, the vapor phase propylene returning to the propylene compressor 805 from the secondary flash tank 503 has a pressure of 0.6 MPa and a temperature of 4°C; the vapor phase propylene returning to the propylene compressor 805 from the subcooler B801 has a pressure of 0.3 MPa and a temperature of -20°C; the vapor phase propylene returning to the propylene compressor 805 from the purification tower condenser 502 and the ethylene cryogenic cooler 501 has a pressure of 0.1 MPa and a temperature of -42°C; the propylene gas temperature conveyed from the high and low temperature chlorination refrigeration unit to the suction buffer tank 807 is -32°C; and the propylene gas temperature conveyed from the cracked hydrogen chloride condenser 701 to the suction buffer tank 807 is -42°C.

[0030] Example 11: Refer to Appendix Figure 1 and attached Figure 2The difference in this embodiment lies in the following: in the coal-based ethylene process for producing vinyl chloride, the pressure of the gaseous propylene returning to the propylene compressor 805 from the secondary flash tank 503 is 0.8 MPa and the temperature is 4-7°C; the pressure of the gaseous propylene returning to the propylene compressor 805 from the subcooler B801 is 0.4 MPa and the temperature is -30°C; the pressure of the gaseous propylene returning to the propylene compressor 805 from the purification tower condenser 502 and the ethylene cryogenic cooler 501 is 0.14 MPa and the temperature is -41°C; the temperature of the propylene gas supplied to the suction buffer tank 807 from the high and low temperature chlorination refrigeration unit is -34°C; and the temperature of the propylene gas supplied to the suction buffer tank 807 from the cracked hydrogen chloride condenser 701 is -41°C.

[0031] Example 12: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment lies in the following: in the coal-based ethylene method for producing vinyl chloride, the pressure of the gaseous propylene returning to the propylene compressor 805 from the secondary flash tank 503 is 0.68 MPa and the temperature is 5.8°C; the pressure of the gaseous propylene returning to the propylene compressor 805 from the subcooler B801 is 0.25 MPa and the temperature is -26°C; the pressure of the gaseous propylene returning to the propylene compressor 805 from the purification tower condenser 502 and the ethylene cryogenic cooler 501 is 0.15 MPa and the temperature is -40.5°C; the temperature of the propylene gas supplied to the suction buffer tank 807 from the high and low temperature chlorination refrigeration unit is -35°C; and the temperature of the propylene gas supplied to the suction buffer tank 807 from the cracked hydrogen chloride condenser 701 is -40°C.

[0032] Example 13: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment lies in the following: in the coal-based ethylene process for producing vinyl chloride, the pressure of the gaseous propylene returning to the propylene compressor 805 from the secondary flash tank 503 is 0.75 MPa and the temperature is 5.2°C; the pressure of the gaseous propylene returning to the propylene compressor 805 from the subcooler B801 is 0.1 MPa and the temperature is -28°C; the pressure of the gaseous propylene returning to the propylene compressor 805 from the purification tower condenser 502 and the ethylene cryogenic cooler 501 is 0.2 MPa and the temperature is -38°C; the temperature of the propylene gas supplied to the suction buffer tank 807 from the high and low temperature chlorination refrigeration unit is -36°C; and the temperature of the propylene gas supplied to the suction buffer tank 807 from the cracked hydrogen chloride condenser 701 is -38°C.

[0033] Example 14: Refer to Appendix Figure 1 and attached Figure 2 The difference in this embodiment is that the coal-based ethylene method for producing vinyl chloride is automatically controlled by a PLC control system.

[0034] The above specific embodiments are merely examples of the content of this invention. Any modifications and variations made to this creation by those skilled in the art are within the scope of the patent of this invention, and are not limited to the embodiments described.

Claims

1. A coal-based ethylene method vinyl chloride production system, comprising an ethanol dehydration reaction system (1), a quenching compression and evaporation system (2), a water alkali washing system (3), an adsorber system (4), a low-temperature rectification system (5), a high-low temperature chlorination system (6), a dichloroethane cracking system (7), and a propylene refrigeration circulation system (8), characterized in that: The low-temperature rectification system (5) comprises a demethanizer, a purification column, and a low-temperature rectification refrigeration device; the high-low temperature chlorination system (6) comprises a high-low temperature chlorination reactor and a high-low temperature chlorination refrigeration device; the dichloroethane cracking system (7) comprises a cracking device and a cracking refrigeration device; and the propylene refrigeration circulation system (8) is connected with the low-temperature rectification refrigeration device, the high-low temperature chlorination refrigeration device, and the cracking refrigeration device, respectively.

2. The coal-based ethylene process vinyl chloride production system according to claim 1, characterized by, The propylene refrigeration circulation system (8) comprises a propylene compressor (805), a condenser (802), a high-temperature flash economizer (803), a low-temperature flash economizer (806), a subcooler A (808), a suction buffer tank (807), a bypass suction buffer tank (804), and a subcooler B (801); the outlet pipe of the propylene compressor (805) is divided into two paths, one of which is connected to the low-temperature rectification refrigeration device, and the other of which is connected to the condenser (802); the outlet of the condenser (802) is divided into two paths, one of which is connected to the high-temperature flash economizer (803), and the other of which is connected to the bypass suction buffer tank (804), and the outlet pipe of the bypass suction buffer tank (804) is connected to the propylene compressor (805); the high-temperature flash economizer (803) is connected to the low-temperature flash economizer (806); the outlet of the low-temperature flash economizer (806) is divided into two paths, one of which is connected to the propylene compressor (805), and the other of which is connected to the subcooler A (808); the outlet pipe of the subcooler A (808) is divided into two paths, one of which is connected to the propylene compressor (805), and the other of which is connected to the high-low temperature chlorination refrigeration device, the dichloroethane cracking refrigeration device, and the suction buffer tank (807), respectively; and the suction buffer tank (807) is connected to the propylene compressor (805).

3. The coal-based ethylene process vinyl chloride production system according to claim 1 or 2, characterized by, The low-temperature rectification refrigeration device comprises a purification column reboiler (509), a demethanizer reboiler (508), an ethylene heater (507), a propylene condenser (506), a propylene collection tank (505), a first-stage flash tank (504), a second-stage flash tank (503), a purification column condenser (502), and an ethylene cryostat (501); one of outlet pipes of the propylene compressor (805) is connected to the purification column reboiler (509), the demethanizer reboiler (508), the ethylene heater (507), and the propylene condenser (506) respectively; the outlet pipes of the purification column reboiler (509), the demethanizer reboiler (508), the ethylene heater (507), and the propylene condenser (506) are connected to the propylene collection tank (505) respectively; the propylene collection tank (505) is connected to the first-stage flash tank (504); the outlet pipe of the first-stage flash tank (504) is divided into two paths, one of which is connected to the propylene compressor (805), and the other of which is connected to the second-stage flash tank (503); the outlet of the second-stage flash tank (503) is divided into two paths, one of which is connected to the propylene compressor (805), and the other of which is connected to the subcooler B (801); the outlet of the subcooler B (801) is divided into two paths, one of which is connected to the propylene compressor (805), and the other of which is connected to the purification column condenser (502) and the ethylene cryostat (501) respectively; the outlet pipe of the purification column condenser (502) is connected to the suction buffer tank (807); and the outlet pipe of the ethylene cryostat (501) is connected to the suction buffer tank (807).

4. The coal-based ethylene process vinyl chloride production system according to claim 1 or 2, characterized by, The high-temperature chlorination refrigeration device comprises a high-temperature chlorination liquid ring compressor (604), a low-temperature chlorination reactor exhaust condenser (603), a high-temperature chlorination exhaust condenser (602), and a high-temperature exhaust cooler (601); one of outlet pipes of the subcooler A (808) is connected to the high-temperature chlorination liquid ring compressor (604), the low-temperature chlorination reactor exhaust condenser (603), the high-temperature chlorination exhaust condenser (602), and the high-temperature exhaust cooler (601) respectively; and the outlet pipes of the high-temperature chlorination liquid ring compressor (604), the low-temperature chlorination reactor exhaust condenser (603), the high-temperature chlorination exhaust condenser (602), and the high-temperature exhaust cooler (601) are connected to the suction buffer tank (807).

5. The coal-based ethylene process vinyl chloride production system according to claim 1 or 2, characterized by, The cracking refrigeration device comprises a cracking hydrogen chloride condenser (701); one of outlet pipes of the subcooler A (808) is connected to the cracking hydrogen chloride condenser (701); and the outlet pipe of the cracking hydrogen chloride condenser (701) is connected to the suction buffer tank (807).

6. The coal-based ethylene process vinyl chloride production system according to claim 2, characterized by, The propylene compressor (805) is a multi-stage centrifugal propylene compressor.

7. The coal-based ethylene route vinyl chloride production system according to any one of claims 1 or 2, characterized in that, The system is provided with a PLC automatic control system.

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