Vinyl chloride recovery monomer refining system
The vinyl chloride monomer recovery and purification system, which combines filters, dehydration devices, and distillation units, solves the problem of high impurities in vinyl chloride monomer, thereby improving the purity of vinyl chloride and the quality of subsequent polymerization reactions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- INNER MONGOLIA YIHUA CHEMICAL CO LTD
- Filing Date
- 2025-07-18
- Publication Date
- 2026-06-19
AI Technical Summary
In the production of polyvinyl chloride (PVC), the recovered vinyl chloride monomer contains high levels of impurities, which affects the quality of subsequent polymerization reactions.
A vinyl chloride recovery monomer refining system is adopted, comprising a recovery monomer storage tank, a filter, a dehydration device, a distillation device, and a refined vinyl chloride storage tank connected in series. The filter filters solid particles, the dehydration device removes trace amounts of moisture, and the distillation device separates low-boiling and high-boiling substances to obtain high-purity refined vinyl chloride.
It effectively removes impurities from vinyl chloride monomer, improves the cleanliness of vinyl chloride, reduces equipment blockage, and ensures the quality of subsequent polymerization reactions.
Smart Images
Figure CN224370703U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of polyvinyl chloride production technology, and in particular to a system for refining vinyl chloride monomer recovery. Background Technology
[0002] In the production of polyvinyl chloride (PVC), the reaction is typically considered complete when the vinyl chloride monomer conversion rate reaches 80%–85%, at which point the gas is vented and unreacted vinyl chloride is recovered. This unreacted vinyl chloride is then processed in a recovery unit. This unit uses a gas holder for collection, an alkaline scrubbing tower, and a gas-liquid separator and condenser to process it into liquid monomer, which is stored in a monomer buffer tank. It is then pressurized by a recovery monomer pump, filtered through a pre-filter, and dehydrated in a coalescer before being sent to a recovery monomer storage tank. This recovered liquid monomer is usually a complex mixture, primarily composed of unreacted vinyl chloride monomer, such as vinyl chloride monomer (VCM) from PVC production. It also contains moisture, which may originate from raw materials introduced during the polymerization process, reaction byproducts, or from production equipment or the environment. Additionally, it often contains high-boiling-point impurities, such as 1,1-dichloroethane in vinyl chloride monomer; low-boiling-point impurities, such as acetylene; and other trace impurities, such as iron ions and acidic substances.
[0003] However, while coalescers utilize filter media to coalesce droplets, their ability to handle trace amounts of moisture (such as at the ppm level) is limited, and the filter media is easily contaminated by impurities, affecting long-term stability. Moreover, the presence of the aforementioned high-boiling and low-boiling impurities can severely interfere with subsequent polymerization reactions, reducing polymer quality. Utility Model Content
[0004] This application provides a vinyl chloride recovery monomer purification system to solve the problem that the recovered vinyl chloride monomer has high impurity levels, which affects subsequent polymerization reactions.
[0005] This application provides a vinyl chloride recovery monomer refining system, comprising a recovery monomer storage tank, a filter, a dehydration device, a distillation device, and a refined vinyl chloride storage tank connected in series.
[0006] The distillation unit is also connected to a vessel residue treatment unit.
[0007] Optionally, the dehydration device includes a solid alkali drying tower, a molecular sieve adsorption tower, and a first dust filter connected in series.
[0008] Optionally, the backflush gas inlet of the molecular sieve adsorption tower is also connected in sequence to the first valve, the check valve, the electric heater and the nitrogen purging line, and the nitrogen purging line is also connected to the molecular sieve adsorption tower through the second valve and the first valve.
[0009] The backflush gas output end of the molecular sieve adsorption tower is also connected in sequence to the second dust filter, the third valve, the first condenser and the backflush gas treatment device;
[0010] The second dust filter is also connected to the backflush air treatment device via a fourth valve;
[0011] The first condenser is also connected to a vinyl chloride recovery tank.
[0012] Optionally, the distillation unit includes a low-boiling column and a high-boiling column connected in series;
[0013] The top of the low-boiling tower is connected to the non-condensable gas treatment section through a low-boiling condenser. The low-boiling condenser is also connected to the low-boiling tower in a loop through the first condenser and the first reflux pump.
[0014] The top of the high-boiling tower is connected to the non-condensable gas treatment section through a high-boiling condenser. The high-boiling condenser is also connected to the high-boiling tower in a loop through a second condenser and a second reflux pump. The second reflux pump is also connected to the refined vinyl chloride storage tank.
[0015] The bottom of the high-boiling-point tower is also connected to a bottom residue treatment device.
[0016] Optionally, the reactor residue treatment device includes a reactor residue storage tank, a first reactor residue distillation column, a second reactor residue distillation column, and a dichloroethane storage tank connected in series.
[0017] The top of the first residual distillation column is connected in sequence to the first residual condenser, the first residual reflux tank and the first residual reflux pump to form a loop. The first residual condenser is also connected to the vinyl chloride compression section.
[0018] The top of the second residual distillation column is connected in sequence to the second residual condenser, the second residual reflux tank, and the second residual reflux pump to form a loop. The second residual condenser is also connected to the tail gas treatment section.
[0019] Optionally, the filter is one of a basket filter, a security filter, or a titanium rod filter.
[0020] Optionally, multiple filters are arranged in series.
[0021] In this application, the crude vinyl chloride obtained through coalescence separation is first filtered to retain solid particles, thereby improving the cleanliness of the crude vinyl chloride and reducing clogging of subsequent equipment. The filtered crude vinyl chloride is then fed into a dehydration unit for drying and dewatering, removing trace amounts of moisture to obtain dried crude vinyl chloride. Finally, the dried crude vinyl chloride is fed into a distillation unit for distillation, separating low-boiling and high-boiling components to obtain purified vinyl chloride with higher purity. The system of this application, through the combined use of the above devices, purifies the crude vinyl chloride recovered through coalescence, effectively overcoming the drawback of high impurities in the recovered vinyl chloride monomer, which affects subsequent polymerization reactions. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a schematic diagram of a vinyl chloride recovery monomer purification system provided in an embodiment of this application;
[0024] Figure 2 A schematic diagram of a dehydration apparatus is provided for one embodiment of this application;
[0025] Figure 3 A schematic diagram of a distillation apparatus provided in one embodiment of this application;
[0026] Figure 4 This is a schematic diagram of a reactor residue treatment device provided in an embodiment of this application.
[0027] Explanation of reference numerals in the attached figures:
[0028] 1. Recovered unit storage tank; 2. Filter; 3. Dehydration unit; 4. Distillation unit; 5. Refined vinyl chloride storage tank; 6. Reactor residue treatment unit; 30. Nitrogen purging pipeline; 31. Solid alkali drying tower; 32. Molecular sieve adsorption tower; 33. First dust filter; 34. Electric heater; 35. Second dust filter; 36. First condenser; 37. Backflush gas treatment unit; 38. Vinyl chloride recovery tank; 41. Low-boiling tower; 42. High-boiling tower; 43. Non-condensable gas treatment section; 61. Reactor residue storage tank; 62. First reactor residue distillation tower; 63. Second reactor residue distillation tower; 64. Dichloroethane storage tank. Tank; 100, First Valve; 200, Check Valve; 300, Second Valve; 400, Third Valve; 410, First Reflux Pump; 411, Low-boiling Condenser; 412, First Condensation Tank; 420, Second Reflux Pump; 421, High-boiling Condenser; 422, Second Condensation Tank; 500, Fourth Valve; 620, First Reactor Residual Reflux Pump; 621, First Reactor Residual Condenser; 622, First Reactor Residual Reflux Tank; 623, Vinyl Chloride Compression Section; 630, Second Reactor Residual Reflux Pump; 631, Second Reactor Residual Condenser; 632, Second Reactor Residual Reflux Tank; 633, Tail Gas Treatment Section. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.
[0030] like Figure 1 As shown, this application provides a vinyl chloride recovery monomer refining system, including a recovery monomer storage tank 1, a filter 2, a dehydration device 3, a distillation device 4 and a refined vinyl chloride storage tank 5 connected in series.
[0031] The distillation unit 4 is also connected to the residue treatment unit 6.
[0032] During use, the crude vinyl chloride monomer stored in the recovery unit storage tank 1 (which is in liquid state due to the pressurization and cooling processes in the preceding steps) is filtered through filter 2 to remove solid particles and then transferred to dehydration unit 3 for dehydration. The dehydrated and dried crude vinyl chloride is then fed into distillation unit 4 for distillation. The refined vinyl chloride obtained from the distillation process is transferred to refined vinyl chloride storage tank 5 for storage. The residue obtained from the distillation process, i.e., the high-boiling-point substance, is transferred to residue treatment unit 6 for further processing.
[0033] In this application, the crude vinyl chloride obtained through coalescence separation is first filtered through filter 2 to retain solid particles, thereby improving the cleanliness of the crude vinyl chloride and reducing clogging of subsequent equipment. The filtered crude vinyl chloride is then fed into dehydration unit 3 for drying and dewatering, removing trace amounts of moisture to obtain dried crude vinyl chloride. Finally, the dried crude vinyl chloride is fed into distillation unit 4 for distillation, separating low-boiling and high-boiling components to obtain purified vinyl chloride with higher purity. The system of this application, through the combined use of the above devices, purifies the crude vinyl chloride recovered through coalescence, effectively overcoming the drawback of high impurities in the recovered vinyl chloride monomer, which affects subsequent polymerization reactions.
[0034] like Figure 2 As shown, optionally, the dehydration device 3 includes a solid alkali drying tower 31, a molecular sieve adsorption tower 32 and a first dust filter 33 connected in series.
[0035] In this application, during dehydration in the dehydration device 3, the filtered crude vinyl chloride first enters the solid alkali drying tower 31, where the solid alkali particles remove most of the water from the crude vinyl chloride for preliminary dehydration. After preliminary dehydration, the crude vinyl chloride enters the molecular sieve adsorption tower 32, where the molecular sieve (3A molecular sieve) adsorbs and removes trace amounts of water from the crude vinyl chloride (resulting in crude vinyl chloride with a moisture content of less than 50 ppm). After molecular sieve dehydration, the vinyl chloride passes through the first dust filter 33 to retain the molecular sieve powder entrained in the vinyl chloride, ensuring the cleanliness of the output vinyl chloride. The dried crude vinyl chloride is then fed into the distillation device 4 for distillation.
[0036] like Figure 2 As shown, optionally, the backflush gas input end of the molecular sieve adsorption tower 32 is also connected in sequence to the first valve 100, the check valve 200, the electric heater 34 and the nitrogen purging line 30, and the nitrogen purging line 30 is also connected to the molecular sieve adsorption tower 32 through the second valve 300 and the first valve 100.
[0037] The backflush gas output end of the molecular sieve adsorption tower 32 is also connected in sequence to the second dust filter 35, the third valve 400, the first condenser 36 and the backflush gas treatment device 37;
[0038] The second dust filter 35 is also connected to the backflush air treatment device 37 via the fourth valve 500;
[0039] The first condenser 36 is also connected to the vinyl chloride recovery tank 38.
[0040] In this application, when the dehydration medium (i.e., molecular sieve) in the dehydration device 3 needs to be regenerated, the first valve 100, the second valve 300, and the third valve 400 are opened first. The room temperature nitrogen supplied by the nitrogen purging pipeline 30 is used to purge the molecular sieve adsorption tower 32, expelling residual vinyl chloride and other substances from the molecular sieve. After drying in the solid alkali drying tower 31, the gas is then transferred to the second dust filter 35 to trap the solid alkali dust entrained in the gas. The nitrogen mixed with organic gases such as vinyl chloride enters the first condenser 36 through the third valve 400 for condensation, separating the organic gases such as vinyl chloride from the nitrogen. The liquid material obtained after condensation is recovered into the vinyl chloride recovery tank 38 and refined (for example, transferred to the recovery unit storage tank 1 for the refining process in this application). The separated nitrogen is then transferred to the backflush gas treatment device 37 for processing. When no more liquid material is released from the first condenser 36 or when the content of vinyl chloride gas in the gas entering the second dust filter 35 is detected to drop below a preset value, thermal purging regeneration is performed.
[0041] During the thermal purging regeneration process, the second valve 300 and the third valve 400 are closed, and the fourth valve 500 is opened. At this time, the nitrogen supplied by the nitrogen purging pipeline 30 enters the electric heater 34 and is heated to the preset temperature (180~200℃). Then, it is introduced into the molecular sieve adsorption tower 32 for thermal purging, which desorbs the moisture adsorbed on the molecular sieve and discharges it with the hot nitrogen flow. After being filtered by the second dust filter 35, it is discharged through the fourth valve 500 to the backflush gas treatment device 37 for treatment.
[0042] like Figure 3 As shown, optionally, the distillation apparatus 4 includes a low-boiling column 41 and a high-boiling column 42 connected in series.
[0043] The top of the low-boiling tower 41 is connected to the non-condensable gas treatment section 43 through the low-boiling condenser 411. The low-boiling condenser 411 is also connected to the low-boiling tower 41 in a loop through the first condenser 412 and the first reflux pump 410.
[0044] The top of the high-boiling tower 42 is connected to the non-condensable gas treatment section 43 through the high-boiling condenser 421. The high-boiling condenser 421 is also connected to the high-boiling tower 42 in a loop through the second condenser 422 and the second reflux pump 420. The second reflux pump 420 is also connected to the refined vinyl chloride storage tank 5.
[0045] The bottom of the high boiling tower 42 is also connected to the bottom residue treatment device 6.
[0046] When crude vinyl chloride is distilled in distillation unit 4, the dried crude vinyl chloride is first transferred to low-boiling column 41 for bottom removal distillation. The temperature of the circulating water in the low-boiling condenser 411 at the top of the column is controlled at 28~32℃, the operating pressure is not less than 0.09MPaG, the bottom temperature is 63±2℃, the reflux ratio is controlled at 2.9~3.1, and the number of trays is 20~25. In this way, vinyl chloride and impurities with higher boiling points will be condensed by the low-boiling condenser 411 and flow into the first condenser 412. Then, after being flushed by the first reflux pump 410, it is pumped into the column for distillation separation. The low-boiling-point substances that fail to condense are transferred to the non-condensable gas treatment section 43 via the low-boiling-point condenser 411 for further processing (such as further compression, deep condensation, pressure swing, and temperature swing adsorption to separate and recover the non-condensable gas). The high-boiling-point substances (including vinyl chloride and high-boiling-point substances such as dichloroethane) obtained after distillation in the low-boiling-point column 41 are transferred to the high-boiling-point column 42 for further distillation separation. During distillation in the high-boiling-point column 42, the bottom temperature is controlled at 62±2℃ and the top temperature is 50~5℃. At 1℃, the high-boiling condenser 421 uses circulating water at 30~32℃ as the cooling medium, with 30~35 trays and a reflux ratio of 0.57~0.6. Vinyl chloride distilled at the top of the high-boiling column 42 is condensed by the high-boiling condenser 421 and flows into the second condenser 422. It is then pumped back into the high-boiling column 42 by the second reflux pump 420 for further distillation. After switching the corresponding valves, the qualified vinyl chloride obtained from the distillation is pumped into the refined vinyl chloride storage tank 5 for collection via the second reflux pump 420. Non-condensable gases that fail to condense in the high-boiling condenser 421 are introduced into the non-condensable gas treatment section 43 for further processing (including compression, deep condensation, pressure swing, and temperature swing adsorption to separate and recover the non-condensable gases). The residue obtained from the bottom of the high-boiling column 42 is transferred to the residue treatment device 6 for further processing (using pressure swing and temperature swing adsorption methods).
[0047] like Figure 4 As shown, optionally, the reactor residue treatment device 6 includes a reactor residue storage tank 61, a first reactor residue distillation column 62, a second reactor residue distillation column 63 and a dichloroethane storage tank 64 connected in series.
[0048] The top of the first residual distillation column 62 is connected in sequence to the first residual condenser 621, the first residual reflux tank 622 and the first residual reflux pump 620 to form a loop. The first residual condenser 621 is also connected to the vinyl chloride compression section 623.
[0049] The top of the second residual distillation column 63 is connected in sequence to the second residual condenser 631, the second residual reflux tank 632, and the second residual reflux pump 630 to form a loop. The second residual condenser 631 is also connected to the tail gas treatment section 633.
[0050] When the residue treatment device 6 is working, the residue obtained from the bottom of the high-boiling tower 42 is fed into the residue storage tank 61 and then fed into the first residue distillation tower 62 for distillation. At this time, the top temperature of the tower is controlled at 22°C, the bottom temperature at 125°C, the operating pressure at 0.25~0.3MPaG, the reflux ratio at 0.7, and the number of trays at 15~18. The first residue condenser 621 uses 5~10°C chilled brine as the heat exchange medium. In this way, high-boiling materials such as dichloroethane will be condensed in the first residue condenser 621 and flow into the first residue reflux tank 622. Then, it is pumped back into the first residue distillation tower 622 by the first residue reflux pump 620 for re-distillation. The non-condensable gas (mainly vinyl chloride) is transferred to the vinyl chloride compression section 623 for compression, condensation and other recovery treatment. The high-boiling material (mainly dichloroethane) in the first residual distillation column 62 is fed into the second residual distillation column 63 for further distillation. The reboiler temperature is controlled at 80±5℃, the top temperature at 58±2℃, the operating pressure at atmospheric pressure, the reflux ratio at 9.8, and the number of trays at 30~32. The second residual condenser uses circulating cooling water at 28~32℃ as the heat exchange medium. The material distilled at the top of the second residual distillation column 63 is condensed by the second residual condenser 631 and flows into the second residual reflux tank 632. It is then pumped back into the second residual distillation column 63 by the second residual reflux pump 630 for further distillation. The uncondensed material is sent to the tail gas treatment section 633 for processing via the second residual condenser 631. The dichloroethane collected at the reboiler of the second residual distillation column 63 is transferred to the dichloroethane storage tank 64 for recovery.
[0051] Optionally, filter 2 is one of a basket filter, a security filter, or a titanium rod filter.
[0052] In this application, the above-mentioned filter is used to filter vinyl chloride, which can effectively intercept solid particles in vinyl chloride, thereby reducing the occurrence of blockage in subsequent equipment pipelines.
[0053] Optionally, multiple filters 2 are arranged in series.
[0054] In this application, setting multiple filters 2 in series can effectively improve the filtration effect on liquid vinyl chloride.
[0055] A vinyl chloride monomer recovery and purification system, the working process of which is as follows:
[0056] During use, the crude vinyl chloride monomer stored in the recovery tank 1 (which is in a liquid state due to the pressurization and cooling processes in the preceding steps) is filtered through filter 2 to remove solid particles and then transferred to dehydration unit 3 for dehydration. In dehydration unit 3, the filtered crude vinyl chloride first enters the solid alkali drying tower 31, where the solid alkali particles remove most of the water, resulting in preliminary dehydration. After preliminary dehydration, the crude vinyl chloride enters the molecular sieve adsorption tower 32, where the molecular sieve (3A molecular sieve) adsorbs and removes trace amounts of water (resulting in crude vinyl chloride with a moisture content of less than 50 ppm). The dehydrated vinyl chloride then passes through the first dust filter 33 to retain any entrained molecular sieve powder, ensuring the cleanliness of the output vinyl chloride. The dried crude vinyl chloride is then fed into the distillation unit 4 for distillation.
[0057] When crude vinyl chloride is distilled in distillation unit 4, the dried crude vinyl chloride is first transferred to low-boiling column 41 for bottom removal distillation. The temperature of the circulating water in the low-boiling condenser 411 at the top of the column is controlled at 28~32℃, the operating pressure is not less than 0.09MPaG, the bottom temperature is 63±2℃, the reflux ratio is controlled at 2.9~3.1, and the number of trays is 20~25. In this way, vinyl chloride and impurities with higher boiling points will be condensed by the low-boiling condenser 411 and flow into the first condenser 412. Then, after being flushed by the first reflux pump 410, it is pumped into the column for distillation separation. The low-boiling-point substances that fail to condense are transferred to the non-condensable gas treatment section 43 via the low-boiling-point condenser 411 for further processing (such as further compression, deep condensation, pressure swing, and temperature swing adsorption to separate and recover the non-condensable gas). The high-boiling-point substances (including vinyl chloride and other high-boiling-point substances such as dichloroethane) obtained after distillation in the low-boiling-point column 41 are transferred to the high-boiling-point column 42 for further distillation and separation. During distillation in the high-boiling-point column 42, the bottom temperature is controlled at 62±2℃ and the top temperature is controlled at 50~5℃. At 1℃, the high-boiling condenser 421 uses circulating water at 30~32℃ as the cooling medium, with 30~35 trays and a reflux ratio of 0.57~0.6. Vinyl chloride distilled at the top of the high-boiling column 42 is condensed by the high-boiling condenser 421 and flows into the second condenser 422. It is then pumped back into the high-boiling column 42 by the second reflux pump 420 for multiple distillations. After switching the corresponding valves, the qualified vinyl chloride obtained from the distillation is pumped into the refined vinyl chloride storage tank 5 for collection via the second reflux pump 420. Non-condensable gases that fail to condense in the high-boiling condenser 421 are introduced into the non-condensable gas treatment section 43 for further processing (including compression, deep condensation, pressure swing, and temperature swing adsorption to separate and recover the non-condensable gases). The residue obtained from the bottom of the high-boiling column 42 is transferred to the residue treatment device 6 for further processing.
[0058] When the residue treatment device 6 is working, the residue obtained from the bottom of the high-boiling tower 42 is fed into the residue storage tank 61 and then fed into the first residue distillation tower 62 for distillation. At this time, the top temperature of the tower is controlled at 22°C, the bottom temperature at 125°C, the operating pressure at 0.25~0.3MPaG, the reflux ratio at 0.7, and the number of trays at 15~18. The first residue condenser 621 uses 5~10°C chilled brine as the heat exchange medium. In this way, high-boiling materials such as dichloroethane will be condensed in the first residue condenser 621 and flow into the first residue reflux tank 622. Then, it is pumped back into the first residue distillation tower 622 by the first residue reflux pump 620 for re-distillation. The non-condensable gas (mainly vinyl chloride) is transferred to the vinyl chloride compression section 623 for compression, condensation and other recovery treatment. The high-boiling material (mainly dichloroethane) in the first residual distillation column 62 is fed into the second residual distillation column 63 for further distillation. The reboiler temperature is controlled at 80±5℃, the top temperature at 58±2℃, the operating pressure at atmospheric pressure, the reflux ratio at 9.8, and the number of trays at 30~32. The second residual condenser uses circulating cooling water at 28~32℃ as the heat exchange medium. The material distilled at the top of the second residual distillation column 63 is condensed by the second residual condenser 631 and flows into the second residual reflux tank 632. It is then pumped back into the second residual distillation column 63 by the second residual reflux pump 630 for further distillation. The uncondensed material is sent to the tail gas treatment section 633 for processing via the second residual condenser 631. The dichloroethane collected at the reboiler of the second residual distillation column 63 is transferred to the dichloroethane storage tank 64 for recovery.
[0059] When the dehydration medium in the dehydration device 3 needs to be regenerated, the first valve 100, the second valve 300, and the third valve 400 are opened first. The room temperature nitrogen supplied by the nitrogen purging pipeline 30 is used to purge the molecular sieve adsorption tower 32, expelling residual vinyl chloride and other substances from the molecular sieve. After drying in the solid alkali drying tower 31, the gas is transferred to the second dust filter 35 to trap solid alkali dust. The nitrogen mixed with organic gases such as vinyl chloride enters the first condenser 36 through the third valve 400 for condensation, separating the organic gases such as vinyl chloride from the nitrogen. The liquid material obtained after condensation is recovered into the vinyl chloride recovery tank 38 and refined (for example, transferred to the recovery unit storage tank 1 for the refining process in this application). The separated nitrogen is then transferred to the backflush gas treatment device 37 for processing. When no more liquid material is released from the first condenser 36 or when the content of vinyl chloride gas in the gas entering the second dust filter 35 is detected to drop below a preset value, thermal purging regeneration is performed.
[0060] During the thermal purging regeneration process, the second valve 300 and the third valve 400 are closed, and the fourth valve 500 is opened. At this time, the nitrogen supplied by the nitrogen purging pipeline 30 enters the electric heater 34 and is heated to the preset temperature (180~200℃). Then, it is introduced into the molecular sieve adsorption tower 32 for thermal purging, which desorbs the moisture adsorbed on the molecular sieve and discharges it with the hot nitrogen flow. After being filtered by the second dust filter 35, it is discharged through the fourth valve 500 to the backflush gas treatment device 37 for treatment.
[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A vinyl chloride monomer recovery and purification system, characterized in that, It includes a recycling unit storage tank (1), a filter (2), a dehydration device (3), a distillation device (4), and a refined vinyl chloride storage tank (5) connected in series. The distillation unit (4) is also connected to the residue treatment unit (6).
2. The vinyl chloride recovery monomer refining system according to claim 1, characterized in that, The dehydration device (3) includes a solid alkali drying tower (31), a molecular sieve adsorption tower (32) and a first dust filter (33) connected in series.
3. The vinyl chloride recovery monomer refining system according to claim 2, characterized in that, The backflush gas input end of the molecular sieve adsorption tower (32) is also connected in sequence to the first valve (100), the check valve (200), the electric heater (34) and the nitrogen purging line (30). The nitrogen purging line (30) is also connected to the molecular sieve adsorption tower (32) through the second valve (300) and the first valve (100). The backflush gas output end of the molecular sieve adsorption tower (32) is also connected in sequence to the second dust filter (35), the third valve (400), the first condenser (36) and the backflush gas treatment device (37); The second dust filter (35) is also connected to the backflush air treatment device (37) via a fourth valve (500); The first condenser (36) is also connected to the vinyl chloride recovery tank (38).
4. The vinyl chloride recovery monomer refining system according to claim 1, characterized in that, The distillation unit (4) includes a low-boiling column (41) and a high-boiling column (42) connected in series. The top of the low-boiling tower (41) is connected to the non-condensable gas treatment section (43) via a low-boiling condenser (411). The low-boiling condenser (411) is also connected to the low-boiling tower (41) in a loop via a first condenser (412) and a first reflux pump (410). The top of the high-boiling tower (42) is connected to the non-condensable gas treatment section (43) via a high-boiling condenser (421). The high-boiling condenser (421) is also connected to the high-boiling tower (42) in a loop via a second condenser (422) and a second reflux pump (420). The second reflux pump (420) is also connected to the refined vinyl chloride storage tank (5). The bottom of the high-boiling tower (42) is also connected to the bottom residue treatment device (6).
5. The vinyl chloride monomer recovery and refining system according to claim 1, characterized in that, The reactor residue treatment device (6) includes a reactor residue storage tank (61), a first reactor residue distillation column (62), a second reactor residue distillation column (63), and a dichloroethane storage tank (64) connected in series. The top of the first residual distillation column (62) is connected in sequence to the first residual condenser (621), the first residual reflux tank (622) and the first residual reflux pump (620) to form a loop. The first residual condenser (621) is also connected to the vinyl chloride compression section (623). The top of the second residual distillation column (63) is connected in sequence to the second residual condenser (631), the second residual reflux tank (632) and the second residual reflux pump (630) to form a loop. The second residual condenser (631) is also connected to the tail gas treatment section (633).
6. The vinyl chloride recovery monomer refining system according to any one of claims 1-5, characterized in that, The filter (2) is one of a basket filter, a security filter, or a titanium rod filter.
7. The vinyl chloride recovery monomer refining system according to any one of claims 1-5, characterized in that, Multiple filters (2) are connected in series.