Full-automatic control system for vinylene carbonate crystallization process

Abstract

The invention belongs to the technical field of production of vinylene carbonate, and particularly relates to a full-automatic control system for a vinylene carbonate crystallization process. Comprising a primary crystallization module, a secondary crystallization module and a temperature control module, wherein the primary crystallization module is used for primary crystallization, primary sweating and primary melting processes of a vinylene carbonate semi-finished product; the secondary crystallization module is connected with the primary crystallization module; the secondary crystallization module is used for carrying out secondary crystallization, secondary sweating and secondary melting processes on the vinylene carbonate solution output by the primary crystallization module; the temperature control module is connected with the primary crystallization module and the secondary crystallization module, and the temperature control module provides temperature control water for each technological process for the primary crystallization module and the secondary crystallization module respectively. According to the invention, automatic operation of the system can be realized, qualified products can be produced, DCS operators only need to monitor and discover abnormal alarms for timely processing, the working efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of vinylene carbonate production, and in particular relates to a fully automatic control system for vinylene carbonate crystallization process. Background Art

[0002] The semi-finished product of vinylene carbonate produced by the distillation unit has a content of about 99.5%, and the product needs to be purified to 99.999% through a crystallization process. The crystallization process involves many equipment and complex operating steps, and requires high proficiency of DCS operators. Once an error occurs, it may lead to problems such as unqualified products or low yields. The material temperature of vinylene carbonate is low during the crystallization process. When the ambient temperature is lower than 15 degrees for a long time, the vinylene carbonate in the equipment and pipelines is easy to solidify, resulting in failure to operate normally. At the same time, if the temperature of vinylene carbonate is higher than 45 degrees for a long time, it is easy to cause discoloration and make the product unqualified, so a temperature-controlled heating is required. The temperature of the boiling water tank is constant at 35-40 degrees, which can meet the heating requirements of this set of crystallization process equipment and pipelines.

[0003] The existing DCS operators operate manually. The entire crystallization process is long and involves many equipments. The regulating valves, shut-off valves, and instrument display data are more. During the manual operation of the DCS operator, it is necessary to frequently adjust according to the data and control each process node at the same time. Otherwise, it will lead to problems such as unqualified products or low yields. The operator's proficiency is extremely high. The traditional crystallizer uses a one-in-one-out method where water enters the bottom of the shell and exits the top. During dynamic crystallization, vinyl carbonate enters from the top of the crystallizer tube and exits from the bottom, which will lead to uneven temperature distribution during crystallization, high temperature at the top and low temperature at the bottom, making it easier for impurities to accumulate at the bottom of the crystallizer during crystallization. During the sweating process, the temperature of the sweating water inlet area at the bottom of the crystallizer will be high. After heat exchange in the crystallizer, the water outlet temperature at the top will be low, resulting in excessive sweating of vinyl carbonate at the bottom of the crystallizer, affecting the product yield. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a fully automatic control system for the vinylene carbonate crystallization process, which can realize fully automatic operation, reduce the dependence on skilled DCS operators, and stably produce qualified products.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a fully automatic control system for a vinylene carbonate crystallization process, comprising:

[0007] The primary crystallization module is used for the primary crystallization, primary sweating and primary melting process of vinylene carbonate semi-finished products;

[0008] A secondary crystallization module is connected to the primary crystallization module, and is used to perform secondary crystallization, secondary sweating and secondary ablation processes on the vinylene carbonate solution output from the primary crystallization module;

[0009] The temperature control module is connected with the primary crystallization module and the secondary crystallization module, and the temperature control module provides temperature control water for each process for the primary crystallization module and the secondary crystallization module respectively.

[0010] The primary crystallization module comprises a primary raw material tank, a primary sweat tank and a primary crystallizer, wherein the shell of the primary crystallizer is a primary crystallization sandwich temperature control structure, and the primary crystallization sandwich temperature control structure is connected to the temperature control module;

[0011] The bottom of the primary crystallizer is connected to the primary raw material tank, the primary sweat tank and the secondary crystallization module through three branch pipelines, and each branch pipeline is provided with a control valve; the primary sweat tank is connected to the primary raw material feed port of the primary raw material tank through a primary sweat pump and a pipeline, and the primary raw material feed port is also connected to the vinyl carbonate semi-finished product feed line. The primary raw material tank is connected to the top of the primary crystallizer and the upstream distillation unit through a primary raw material circulation pump and a primary crystallization circulation pipeline, and each pipeline is provided with a control valve.

[0012] The secondary crystallization module comprises a secondary raw material tank, a secondary sweat tank, a melting tank and a secondary crystallizer, wherein the shell of the secondary crystallizer is a secondary crystallization sandwich temperature control structure, and the secondary crystallization sandwich temperature control structure is connected to the temperature control module;

[0013] The bottom of the secondary crystallizer is connected to the secondary raw material tank, the secondary sweat tank and the melting tank through three branch pipelines, and each branch pipeline is provided with a control valve; the secondary raw material tank is connected to the top of the secondary crystallizer through a secondary raw material circulation pump and a secondary raw material circulation pipeline, the secondary sweat tank is connected to the primary raw material tank through a secondary sweat pump and a pipeline, and the melting tank is connected to the finished product line through a melting pump.

[0014] The primary crystallization interlayer temperature control structure of the primary crystallizer is the same as the secondary crystallization interlayer temperature control structure of the secondary crystallizer, both of which include multiple sections of jackets with independent cavities arranged in sequence along the height direction, and the inlet and outlet of each section of the jacket are respectively provided with a temperature sensor and an automatic regulating valve, and the value displayed by the temperature sensor is interlocked with the opening of the automatic regulating valve.

[0015] The primary raw material tank is provided with a raw material tank weighing module for weighing the raw materials; the secondary raw material tank is provided with a secondary raw material tank weighing module for weighing the secondary raw materials.

[0016] The temperature control module includes a chilled water control module, a sweating water control module and a boiling water control module;

[0017] The primary crystallizer is connected with the chilled water control module, the sweating water control module and the boiling water control module to form a primary chilled water circulation system, a primary sweating water circulation system and a primary boiling water circulation system;

[0018] The secondary crystallizer is connected with the chilled water control module, the sweating water control module and the boiling water control module to form a secondary chilled water circulation system, a secondary sweating water circulation system and a secondary boiling water circulation system;

[0019] The return pipelines of the primary crystallizer and the secondary crystallizer are connected to the compressed air pipeline, and the frozen water, sweat water and boiled water are compressed back by compressed air.

[0020] The chilled water control module includes a chilled water tank and a chilled water pump, wherein the water inlet of the chilled water pump is connected to the bottom of the chilled water tank, and the water outlet of the chilled water pump is respectively connected to the top of the chilled water tank, the primary crystallizer, the secondary crystallizer and the return water main through a plurality of branch pipelines, and each branch pipeline is provided with a control valve; the primary crystallizer and the secondary crystallizer are connected to the top of the chilled water tank through a chilled water return pipeline; the top of the chilled water tank is connected to a 10°C water inlet pipeline.

[0021] The sweating water control module includes a sweating water tank and a sweating water pump, wherein the water inlet of the sweating water pump is connected to the bottom of the sweating water tank through a pipeline, and the water outlet of the sweating water pump is respectively connected to the top of the sweating water tank, the primary crystallizer and the secondary crystallizer through a plurality of branch pipelines, and each branch pipeline is provided with a control valve; the primary crystallizer and the secondary crystallizer are connected to the top of the sweating water tank through a sweating water return pipeline; the top of the sweating water tank is connected to the process water inlet pipeline.

[0022] The boiling water control module includes a boiling water tank and a boiling water pump, wherein the water inlet of the boiling water pump is connected to the bottom of the boiling water tank, and the water outlet of the boiling water pump is respectively connected to the top of the boiling water tank, the primary crystallizer and the secondary crystallizer through a plurality of branch pipelines, and each branch pipeline is provided with a control valve; the primary crystallizer and the secondary crystallizer are connected to the top of the boiling water tank through a boiling water return pipeline; the top of the boiling water tank is connected to the process water inlet pipeline.

[0023] The temperature of the freezing water is 17-18°C, the temperature of the sweating water is 20-22°C, and the temperature of the boiling water is 35-40°C.

[0024] The advantages and beneficial effects of the present invention are as follows: the fully automatic control system for the vinylene carbonate crystallization process provided by the present invention can realize the automatic operation of the system and produce qualified products. The DCS operator only needs to monitor and timely handle abnormal alarms. The temperature difference between the frozen water, sweating water and boiled water in the crystallizer is large. Each use needs to be pressed back to the water tank with compressed air. The amount of water required for freezing and crystallizing in the crystallizer at the same time will be very large. The amount of water required for each crystallizer is about 25 cubic meters. The capacity of the frozen water tank of this control scheme can meet the freezing of one crystallizer, and the remaining water is borrowed from the 10-degree water storage tank of the public works. Although the temperature of the frozen water tank is controlled at 17-18 degrees, the water source of the public works is 10-degree water. The system can automatically control the temperature and implement the back and forth borrowing, which greatly saves the space occupied by the frozen water tank in the workshop and reduces the manufacturing cost of the frozen water tank. The three water tanks adopt the top feeding method, the main function of which is to be away from the suction port of the bottom pump, the mixing effect is better when the water is inlet, and the temperature is more stable when the pump is transported.

[0025] The crystallizer of the present invention adopts a four-section shell structure, and the water inlet of each section is controlled separately, so that the temperature distribution of the upper and lower parts of the crystallizer is kept as uniform as possible during crystallization and sweating, which significantly improves the product processing efficiency and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of a fully automatic control system for a vinylene carbonate crystallization process according to the present invention;

[0027] Figure 2 It is a structural schematic diagram of the primary crystallization module in the present invention;

[0028] Figure 3 It is a structural schematic diagram of the secondary crystallization module in the present invention;

[0029] Figure 4 It is a structural schematic diagram of the chilled water control module in the present invention;

[0030] Figure 5 It is a structural schematic diagram of the sweat water control module in the present invention;

[0031] Figure 6 It is a structural schematic diagram of the boiling water control module in the present invention.

[0032] In the figure: 1-feed cut-off valve, 2-primary raw material tank, 3-raw material tank weighing module, 4-primary raw material circulation pump, 5-primary crystallizer feed regulating valve, 6-primary crystallizer inlet flow meter, 7-chilled water pump, 8-chilled water tank circulation regulating valve, 9-chilled water pump outlet pressure gauge, 10-chilled water tank thermometer, 11-chilled water tank steam regulating valve, 12-chilled water tank level gauge, 13-chilled water tank, 14-external regulating valve, 15-chilled water tank inlet regulating valve, 16-primary crystallization chilled water return cut-off valve, 17-primary crystallization drain cut-off valve, 18-primary crystallization chilled water inlet cut-off valve, 19-chilled water return regulating valve, 20-primary crystallization total inlet regulating valve, 21-sampling point, 22-primary crystallization inlet Water regulating valve a, 23-primary crystallization water inlet regulating valve b, 24-primary crystallization water inlet regulating valve c, 25-primary crystallization water inlet regulating valve d, 26-primary crystallizer thermometer a, 27-primary crystallizer thermometer b, 28-primary crystallizer thermometer c, 29-primary crystallizer thermometer d, 30-10 degree water return regulating valve, 31-chilled water tank inlet flowmeter, 32-10 degree water return flowmeter, 33-primary raw material tank circulation cut-off valve, 34-return upstream distillation unit cut-off valve, 35-chilled water return flowmeter, 36-primary crystallizer compressed air inlet cut-off valve, 37-primary crystallizer compressed air inlet flowmeter, 38-chilled water tank on-site venting line, 39-sweating water tank, 40-process water inlet regulating valve a, 41-sweating water tank level gauge, 42-10 degree water supply regulating valve, 43-sweating water tank steam regulating valve, 44-sweating water tank thermometer, 45-sweating water pump, 46-sweating water pump outlet pressure gauge, 47-sweating water circulation regulating valve, 48-primary sweat tank feed cut-off valve, 49-primary crystallization sweating water inlet cut-off valve, 50-primary crystallization sweating return water cut-off valve, 51-primary crystallization return water main valve, 52-primary crystallization secondary line cut-off valve, 53-primary crystallization water inlet flowmeter, 54-primary sweat tank, 55-primary sweat tank weighing module, 56-primary sweat pump, 57-primary sweat pump outlet cut-off valve, 58-process water inlet regulating valve b, 59-boiling water tank level gauge, 60-boiling water tank thermometer, 61 -Steam regulating valve of boiling water tank, 62-boiling water tank, 63-boiling water pump, 64-boiling water pump outlet pressure gauge, 65-boiling water return regulating valve, 66-primary crystallizer boiling water inlet cut-off valve, 67-primary crystallization return water cut-off valve, 68-boiling water tank on-site venting line, 69-secondary raw material tank, 70-secondary raw material tank weighing module, 71-secondary sweat tank, 72-secondary sweat tank weighing module, 73-primary crystallization discharge cut-off valve, 74-secondary raw material circulation pump, 75-secondary crystallizer feed regulating valve, 76-secondary crystallization circulation cut-off valve, 77-secondary crystallizer air intake flowmeter, 78-transport cut-off valve, 79-secondary crystallizer compressed air intake flowmeter, 80-secondary crystallizer compressed air intake cut-off valve,81-Secondary crystallization chilled water return cut-off valve, 82-Secondary crystallization sweat return cut-off valve, 83-Secondary crystallization return cut-off valve, 84-Secondary crystallization return cut-off valve, 85-Secondary crystallizer thermometer a, 86-Secondary crystallization water inlet regulating valve a, 87-Secondary crystallizer thermometer b, 88-Secondary crystallization water inlet regulating valve b, 89-Secondary crystallizer thermometer c, 90-Secondary crystallization water inlet regulating valve c, 91-Secondary crystallizer thermometer d, 92-Secondary crystallization water inlet regulating valve d, 93-Secondary crystallization drain cut-off valve, 94-Secondary crystallization total water inlet regulating valve, 95-Secondary crystallization outlet Material cut-off valve, 96-secondary sweat tank feed cut-off valve, 97-secondary crystallizer melting water inlet cut-off valve, 98-secondary crystallization sweat inlet cut-off valve, 99-secondary crystallization secondary line cut-off valve, 100-secondary sweat pump outlet cut-off valve, 101-secondary sweat pump, 102-melting tank, 103-melting tank weighing module, 104-melting pump, 105-equipment pipeline, 106-heating circulation pump, 107-sweating water tank on-site venting line, 108-primary crystallizer, 109-secondary crystallizer, 110-secondary crystallization water inlet flowmeter, 111-secondary crystallization chilled water inlet cut-off valve. , DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] See also Figures 1 to 6 As shown, the present invention provides a fully automatic control system for vinyl carbonate crystallization process, comprising a primary crystallization module, a secondary crystallization module and a temperature control module, wherein the primary crystallization module is used for primary crystallization, primary sweating and primary melting processes of vinyl carbonate semi-finished products; the secondary crystallization module is connected to the primary crystallization module, and the secondary crystallization module is used for performing secondary crystallization, secondary sweating and secondary melting processes on the vinyl carbonate solution output by the primary crystallization module; the temperature control module is connected to the primary crystallization module and the secondary crystallization module, and the temperature control module provides temperature control water for each process for the primary crystallization module and the secondary crystallization module respectively.

[0035] See also Figure 1 , Figure 2As shown, in an embodiment of the present invention, a primary crystallization module includes a primary raw material tank 2, a primary sweat tank 54 and a primary crystallizer 108, wherein the shell of the primary crystallizer 108 is a primary crystallization interlayer temperature control structure, and the primary crystallization interlayer temperature control structure is connected to the temperature control module; the bottom of the primary crystallizer 108 is respectively connected to the primary raw material tank 2, the primary sweat tank 54 and the secondary crystallization module through three branch pipelines, and each branch pipeline is provided with a primary raw material tank circulation shut-off valve 33, a primary sweat tank feed shut-off valve 48 and a primary crystallization discharge shut-off valve 73 in sequence; the primary sweat tank 54 is connected to the primary raw material feed port of the primary raw material tank 2 through a primary sweat pump 56, a primary sweat pump outlet shut-off valve 57 and a pipeline, and the primary raw material feed port is also connected to the vinyl carbonate semi-finished product feed line, and the vinyl carbonate semi-finished product feed line is provided with a feed shut-off valve 1. The primary raw material tank 2 is connected to the top of the primary crystallizer 108 and the upstream distillation unit through the primary raw material circulation pump 4 and the primary crystallization circulation pipeline. The primary crystallization circulation pipeline is provided with a primary crystallizer air inlet flowmeter 6 and a primary crystallizer feed regulating valve 5. The pipeline connected to the upstream distillation unit is provided with a return upstream distillation unit shut-off valve 34.

[0036] Furthermore, the primary raw material tank 2 is provided with a raw material tank weighing module 3, and the raw material tank weighing module 3 is used for weighing the raw materials. The primary sweat tank 54 is provided with a primary sweat tank weighing module 55 for weighing sweat.

[0037] See also Figure 3 As shown, in the embodiment of the present invention, the secondary crystallization module includes a secondary raw material tank 69, a secondary sweat tank 71, a melting tank 102 and a secondary crystallizer 109, wherein the shell of the secondary crystallizer 109 is a secondary crystallization sandwich temperature control structure, and the secondary crystallization sandwich temperature control structure is connected to the temperature control module; the bottom of the secondary crystallizer 109 is respectively connected to the secondary raw material tank 69, the secondary sweat tank 71 and the melting tank 102 through three branch pipelines, and each branch pipeline is respectively provided with a secondary crystallization circulation cut-off valve 76, a secondary sweat tank feed cut-off valve 96 and a secondary crystallization discharge cut-off valve 95, and a sampling point 21 is provided at the front end of the secondary sweat tank feed cut-off valve 96. The secondary raw material tank 69 is connected to the top of the secondary crystallizer 109 through a secondary raw material circulation pump 74 and a secondary raw material circulation pipeline, and a secondary crystallizer air intake flowmeter 77 and a secondary crystallizer feed regulating valve 75 are provided on the secondary raw material circulation pipeline. The secondary sweat tank 71 is connected to the primary raw material tank 2 through the secondary sweat pump 101, the secondary sweat pump outlet cut-off valve 100 and the pipeline, and the pipeline is connected to the secondary raw material circulation pipeline through the bypass pipeline and the delivery cut-off valve 78. The melting tank 102 is connected to the finished product line through the melting pump 104, and the melting tank 102 is also provided with a melting tank weighing module 103.

[0038] Furthermore, the secondary raw material tank 69 is provided with a secondary raw material tank weighing module 70 for weighing the secondary raw material, the secondary sweat tank 71 is provided with a secondary sweat tank weighing module 72 , and the melting tank 102 is provided with a melting tank weighing module 103 .

[0039] In an embodiment of the present invention, the primary crystallization interlayer temperature control structure of the primary crystallizer 108 and the secondary crystallization interlayer temperature control structure of the secondary crystallizer 109 are the same, both of which include multiple sections of jackets with independent cavities arranged in sequence along the height direction, and the inlet and outlet of each section of the jacket are respectively provided with a temperature sensor and an automatic regulating valve, and the value displayed by the temperature sensor is interlocked with the opening of the automatic regulating valve.

[0040] Specifically, see Figure 2 As shown, both the primary crystallization interlayer temperature control structure and the secondary crystallization interlayer temperature control structure are provided with four-section jackets; the water inlets of the four-section jackets of the primary crystallization interlayer temperature control structure are provided with primary crystallization water inlet regulating valve a22, primary crystallization water inlet regulating valve b23, primary crystallization water inlet regulating valve c24 and primary crystallization water inlet regulating valve d25 from top to bottom in order, and the primary crystallization water inlet regulating valve a22, primary crystallization water inlet regulating valve b23, primary crystallization water inlet regulating valve c24 and primary crystallization water inlet regulating valve d25 are connected in parallel to the main water inlet pipeline and the return water main pipe, the main water inlet pipeline is provided with a primary crystallization main water inlet regulating valve 20 and a primary crystallization water inlet flowmeter 53, and the return water main pipe is provided with a primary crystallization drain cut-off valve 17. The main water inlet pipeline and the return water main pipe are connected through a primary crystallization secondary line cut-off valve 52. The four jackets are provided with a primary crystallizer thermometer a26, a primary crystallizer thermometer b27, a primary crystallizer thermometer c28 and a primary crystallizer thermometer d29 from top to bottom. The recovery ports of the four jackets are connected in parallel to the primary crystallization total return pipeline, and the primary crystallization total return pipeline is provided with a primary crystallization return water main valve 51 for connection.

[0041] Specifically, see Figure 3As shown, the four-section jackets of the secondary crystallization interlayer temperature control structure are provided with secondary crystallizer thermometer a85, secondary crystallizer thermometer b87, secondary crystallizer thermometer c89 and secondary crystallizer thermometer d91 from top to bottom; the water inlets of the four-section jackets of the secondary crystallization interlayer temperature control structure are provided with secondary crystallization water inlet regulating valve a86, secondary crystallization water inlet regulating valve b88, secondary crystallization water inlet regulating valve c90 and secondary crystallization water inlet regulating valve d92 from top to bottom, the secondary crystallization water inlet regulating valve a86, secondary crystallization water inlet regulating valve b88, secondary crystallization water inlet regulating valve c90 and secondary crystallization water inlet regulating valve d92 are connected in parallel to the secondary crystallization main water inlet pipeline, and the secondary crystallization main water inlet pipeline is provided with a secondary crystallization main water inlet regulating valve 94 and a secondary crystallization water inlet flowmeter 110. The return ports of the four-section jacket are connected in parallel to the secondary crystallization return pipeline, the secondary crystallization return pipeline is connected to the temperature control module and the compressed air pipeline, the secondary crystallization return pipeline is provided with a secondary crystallization return water cut-off valve 84, and the secondary crystallization total water inlet pipeline is connected to the secondary crystallization return pipeline through the secondary crystallization secondary line cut-off valve 99 and the pipeline. The secondary crystallizer compressed air intake flowmeter 79 and the secondary crystallizer compressed air intake cut-off valve 80 are provided on the second compressed air pipeline.

[0042] See also Figures 1 to 6 As shown, in an embodiment of the present invention, the temperature control module includes a chilled water control module, a sweating water control module and a boiling water control module; the primary crystallizer 108 is connected with the chilled water control module, the sweating water control module and the boiling water control module to form a primary chilled water circulation system, a primary sweating water circulation system and a primary boiling water circulation system; the secondary crystallizer 109 is connected with the chilled water control module, the sweating water control module and the boiling water control module to form a secondary chilled water circulation system, a secondary sweating water circulation system and a secondary boiling water circulation system; the return pipelines of the primary crystallizer 108 and the secondary crystallizer 109 are connected with the compressed air pipeline, and the chilled water, sweating water and boiling water are pressed back by compressed air.

[0043] See also Figure 1 , Figure 4As shown, in an embodiment of the present invention, the chilled water control module includes a chilled water tank 13 and a chilled water pump 7, wherein the water inlet of the chilled water pump 7 is connected to the bottom of the chilled water tank 13, and the water outlet of the chilled water pump 7 is respectively connected to the top of the chilled water tank 13, the primary crystallizer 108, the secondary crystallizer 109 and the return water main through a plurality of branch pipelines, each branch pipeline is provided with a control valve, and a chilled water pump outlet pressure gauge 9 is provided at the water outlet of the chilled water pump 7; the primary crystallizer 108 and the secondary crystallizer 109 are connected to the top of the chilled water tank 13 through a chilled water return pipeline, and a chilled water return regulating valve 19 and a chilled water return flowmeter 35 are provided on the chilled water return pipeline, and the chilled water return pipeline is connected to the 10°C return water main through a 10-degree water return flowmeter 32 and a 10-degree water return regulating valve 30. The top of the chilled water tank 13 is connected to a 10°C water inlet pipeline, on which a chilled water tank inlet flowmeter 31 and a chilled water tank inlet regulating valve 15 are provided. A chilled water tank level gauge 12 and a chilled water tank on-site vent line 38 are also provided on the top of the chilled water tank 13, and a chilled water tank thermometer 10 and a chilled water tank steam regulating valve 11 are provided at the bottom of the chilled water tank 13.

[0044] Specifically, a chilled water tank circulation regulating valve 8 is provided on the circulation pipeline between the outlet of the chilled water pump 7 and the top of the chilled water tank 13. An external regulating valve 14 is provided on the pipeline connecting the outlet of the chilled water pump 7 and the 10°C return water main pipe; a primary crystallization chilled water inlet cut-off valve 18 and a secondary crystallization chilled water inlet cut-off valve 111 are provided on the pipeline connecting the outlet of the chilled water pump 7 and the primary crystallizer 108 and the secondary crystallizer 109, respectively; a primary crystallization chilled water return cut-off valve 16 and a secondary crystallization chilled water return cut-off valve 81 are provided on the pipeline connecting the chilled water return pipeline and the primary crystallizer 108 and the secondary crystallizer 109, respectively.

[0045] See also Figure 1 , Figure 5 As shown, in an embodiment of the present invention, the sweating water control module includes a sweating water tank 39 and a sweating water pump 45, wherein the water inlet of the sweating water pump 45 is connected to the bottom of the sweating water tank 39 through a pipeline, and the water outlet of the sweating water pump 45 is respectively connected to the top of the sweating water tank 39, the primary crystallizer 108 and the secondary crystallizer 109 through a plurality of branch pipelines, each branch pipeline is provided with a control valve, and a sweating water pump outlet pressure gauge 46 is provided at the water outlet of the sweating water pump 45; the primary crystallizer 108 and the secondary crystallizer 109 are connected to the top of the sweating water tank 39 through a sweating water return pipeline; the top of the sweating water tank 39 is connected to the process water inlet pipeline, and the process water inlet pipeline is provided with a process water inlet regulating valve a40. A sweating water tank level gauge 41 and a sweating water tank on-site drain line 107 are provided on the top of the sweating water tank 39, and a sweating water tank thermometer 44, a 10-degree water supply regulating valve 42 and a sweating water tank steam regulating valve 43 are provided on the lower part of the sweating water tank 39.

[0046] Specifically, a sweat water circulation regulating valve 47 is provided on the circulation pipeline between the water outlet of the sweat water pump 45 and the top of the sweat water tank 39, and a primary crystallization sweat water inlet cut-off valve 49 and a secondary crystallization sweat water inlet cut-off valve 98 are provided on the sweat water inlet pipeline connecting the water outlet of the sweat water pump 45 and the primary crystallizer 108 and the secondary crystallizer 109, respectively. A primary crystallization sweat return water cut-off valve 50 and a secondary crystallization sweat return water cut-off valve 82 are provided on the pipeline connecting the sweat water return pipeline and the primary crystallizer 108 and the secondary crystallizer 109, respectively.

[0047] See also Figure 1 , Figure 6 As shown, in an embodiment of the present invention, the boiling water control module includes a boiling water tank 62 and a boiling water pump 63, wherein the water inlet of the boiling water pump 63 is connected to the bottom water outlet of the boiling water tank 62, and the water outlet of the boiling water pump 63 is respectively connected to the top of the boiling water tank 62, the primary crystallizer 108 and the secondary crystallizer 109 through a plurality of branch pipelines, each branch pipeline is provided with a control valve, and a boiling water pump outlet pressure gauge 64 is provided at the water outlet of the boiling water pump 63; the primary crystallizer 108 and the secondary crystallizer 109 are connected to the top of the boiling water tank 62 through a boiling water return pipeline; the top of the boiling water tank 62 is connected to the process water inlet pipeline, and the process water inlet pipeline is provided with a process water inlet regulating valve b58. The top of the boiling water tank 62 is also provided with a boiling water tank level meter 59 and a boiling water tank on-site venting line 68, and the lower part of the boiling water tank 62 is provided with a boiling water tank thermometer 60 and a boiling water tank steam regulating valve 61.

[0048] Furthermore, the bottom outlet of the boiling water tank 62 is connected to the top of the boiling water tank 62 through the heat-tracing circulation pump 106 and the equipment pipeline 105. A boiling water return regulating valve 65 is provided on the circulation pipeline between the outlet of the boiling water pump 63 and the top of the boiling water tank 62, and a primary crystallizer boiling water inlet cut-off valve 66 and a secondary crystallizer boiling water inlet cut-off valve 97 are provided on the boiling water inlet pipeline between the outlet of the boiling water pump 63 and the primary crystallizer 108 and the secondary crystallizer 109, respectively; a primary crystallization return water cut-off valve 67 and a secondary crystallization return water cut-off valve 83 are provided on the pipeline connecting the boiling water return pipeline to the primary crystallizer 108 and the secondary crystallizer 109, respectively.

[0049] Specifically, the temperature of frozen water is 17-18°C, the temperature of sweating water is 20-22°C, and the temperature of boiling water is 35-40°C.

[0050] In the embodiment of the present invention, all the shut-off valves have a switch signal feedback and a timing alarm function after the partial shut-off valve is in the open state. All shut-off valve commands need to receive feedback, otherwise the alarm is triggered. The timing function is triggered when the partial shut-off valve is in the open state. If it is not closed after the set time, the timeout alarm function is triggered. If an alarm is found, the operator confirms the cause of the abnormality in time. This system takes a primary crystallizer and a secondary crystallizer as an example. In fact, it can be a combination of many crystallizers. The control system is more complicated, but the principle is the same.

[0051] The present invention provides a fully automatic control system for vinylene carbonate crystallization process, and its working principle is:

[0052] Primary raw material circulation process: Click the system start button on the operation interface, the system automatically detects the raw material amount of the upstream vinylene carbonate semi-finished product storage tank. When it exceeds 35 tons, the system automatically opens the feed cut-off valve 1 to feed the primary raw material tank 2, and displays the feed weight through the raw material tank weighing module 3. When the displayed value reaches 30 tons, the system automatically closes the feed cut-off valve 1. The system automatically detects the closing return signal of the feed cut-off valve 1 and the displayed value of the raw material tank weighing module 3 is not changing, and issues the next instruction to open the primary raw material tank circulation cut-off valve 33 and start the primary raw material circulation pump 4. The system automatically detects the pump running current. In the stage of excessive starting current, the primary crystallizer feed regulating valve 5 is in a closed state; when the current stabilizes for 3 seconds, the primary crystallizer feed regulating valve 5 gradually and automatically opens to 35% of the opening. When the opening is reached, it is automatically associated with the primary crystallizer intake flowmeter 6 to display data, and the set value is 18t / h. The primary crystallizer feed regulating valve 5 automatically stabilizes at about 18t / h according to the displayed value of the primary crystallizer intake flowmeter 6.

[0053] Chilled water tank start-up process: After the raw material circulation pump 4 has been running stably for 1 minute, the system automatically detects the indication of the chilled water tank level gauge 12. When the indication is lower than 20%, the chilled water tank inlet regulating valve 15 of 10-degree water is automatically opened; when the indication of the chilled water tank level gauge 12 reaches 20%, an instruction to start the chilled water pump 7 is issued. After the machine pump current is stable for 3 seconds, the chilled water tank circulation regulating valve 8 gradually opens automatically to 50% opening. When the opening is reached, it is automatically linked to the chilled water pump outlet pressure gauge 9, and the displayed data setting value is 0.5 MPa. The chilled water tank circulation regulating valve 8 is automatically controlled. The system automatically detects the status of the chilled water tank 13. When the chilled water tank thermometer 10 is between 17 and 18 degrees, the chilled water tank steam regulating valve 11 is always in automatic status. When the temperature is lower than 17 degrees, the chilled water tank steam regulating valve 11 is automatically opened. When the temperature reaches 17 degrees, the chilled water tank steam regulating valve 11 is closed. If the temperature exceeds 18 degrees, the system automatically detects the display of the chilled water tank liquid level gauge 12. When it is lower than 80%, the chilled water tank water inlet regulating valve 15 is opened to replenish water to the chilled water tank 13. At this time, the maximum limit of the temperature adjustment and water replenishment valve position is 20%. When the chilled water tank thermometer 10 displays 18 degrees, the water replenishment is stopped. If the chilled water tank level gauge 12 reaches 80%, and the chilled water tank thermometer 10 has not exceeded 18 degrees, the external delivery regulating valve 14 is gradually fully opened, and the water output of the chilled water tank 13 is greater than the water inlet. When it reaches 18 degrees, the external delivery regulating valve 14 is closed; when the chilled water tank level gauge 12 reaches 80%, the chilled water tank inlet regulating valve 15 is closed, and then the external delivery regulating valve 14 is always in the automatic state, and the chilled water tank level gauge 12 opens when it reaches 80%. In this way, the chilled water tank thermometer 10 will display 17-18 degrees, and the chilled water tank level gauge 12 will display 80%. This process only needs to be started when the material is first added, and the system will run continuously thereafter.

[0054] Primary crystallization process: The system detects that the operation of the chilled water is normal. The detection conditions include that the operation signal and current display of the chilled water pump 7 are normal, and the chilled water tank thermometer 10 and the chilled water tank level gauge 12 are normal. At this time, the primary crystallization instruction is executed, and the primary crystallization chilled water return cut-off valve 16, the primary crystallization return water main valve 51, the primary crystallization chilled water inlet cut-off valve 18 and the chilled water return regulating valve 19 are opened in sequence. At this time, the opening of the chilled water return regulating valve 19 is 100%, and the setting value logic of the chilled water return regulating valve 19 is to automatically adjust the valve position to 100% when the crystallizer is put into use with chilled water. The system automatically opens the primary crystallization main inlet regulating valve 20, and forms automatic control with the primary crystallization inlet flowmeter 53, and the flow setting value is 30t / h. According to the experience of manual operation calibration, the output valve position of the primary crystallization water inlet regulating valve a22 is 85%, the output valve position of the primary crystallization water inlet regulating valve b23 is 63%, the output valve position of the primary crystallization water inlet regulating valve c24 is 57%, and the output valve position of the primary crystallization water inlet regulating valve d25 is 50%. Under this valve position, the crystallization rate of vinylene carbonate is relatively fast, and the temperatures of the primary crystallizer thermometers a26, b27, c28 and d29 in the primary crystallizer 108 at the end of crystallization are similar. The analysis results after melting show that there are few crystallized impurities, proving that under the operating conditions of this equipment, the output valve position is set to match the process. Because the material temperature in the primary raw material tank 2 is relatively high, generally at 30-40 degrees, during the crystallization cycle, the temperature in the chilled water tank 13 will gradually rise. When the chilled water tank thermometer 10 reaches 18 degrees, the system automatically opens the chilled water tank water inlet regulating valve 15. At this time, the chilled water tank water inlet regulating valve 15 is automatically associated with the chilled water tank thermometer 10, and the set value is 18 degrees. With the entry of 10-degree water, the chilled water tank liquid level will gradually rise; when the chilled water tank liquid level gauge 12 shows that the liquid level reaches 70%, the 10-degree water return valve is opened. The regulating valve 30, the 10-degree water return regulating valve 30 and the 10-degree water return flowmeter 32 are automatically associated, and the chilled water tank inlet regulating valve 15 and the chilled water tank inlet flowmeter 31 are automatically associated. At this time, the system instructs the chilled water tank inlet flowmeter 31 and the 10-degree water return flowmeter 32 to be in an equivalent relationship, in order to ensure that the liquid level of the chilled water tank 13 is stable at 70%; at the same time, the chilled water tank inlet flowmeter 31 and the chilled water tank thermometer 10 are automatically associated, in order to ensure that the temperature in the chilled water tank 13 is stable at 18 degrees.The chilled water return regulating valve 19 is automatically associated with the chilled water return flowmeter 35. The setting value logic of the chilled water return regulating valve 19 is that when the crystallizer is put into use with chilled water, the valve position is 100% by default. When the chilled water tank level meter 12 reaches 70%, another set of control logic is triggered. The control method is to automatically detect the crystallization state of the primary and secondary crystallizers, confirm the switch state of the chilled water inlet cut-off valve 18 of the primary crystallizer and the chilled water inlet cut-off valve 111 of the secondary crystallizer. If it is in the open state, then the circulation flow rate of one way is 30t / h, and the two ways are 60t / h. The automatic setting value of the chilled water return flowmeter 35 is the total circulation flow required for the primary and secondary crystallization minus the display value of the chilled water tank inlet flowmeter 31, so that the stable control of the chilled water tank level can be achieved. During the primary crystallization process, the material in the primary raw material tank 2 will gradually decrease. When the display value of the raw material tank weighing module 3 is 3t, the primary raw material crystallization ends. Close the primary crystallizer feed regulating valve 5, and close the primary raw material tank circulation shut-off valve 33 after three minutes to allow the liquid vinylene carbonate in the crystallizer to flow back to the raw material tank. Open the return upstream distillation unit shut-off valve 34, and when the raw material tank weighing module 3 displays a value of 0t, close the return upstream distillation unit shut-off valve 34 and stop the primary raw material circulation pump 4.

[0055] Primary crystallization refrigeration water process: the system automatically closes the primary crystallization chilled water inlet cut-off valve 18, the primary crystallization total inlet regulating valve 20 and the primary crystallization chilled water return cut-off valve 16, opens the primary crystallization drainage cut-off valve 17, fully opens the primary crystallization inlet regulating valve a22, the primary crystallization inlet regulating valve b23, the primary crystallization inlet regulating valve c24 and the primary crystallization inlet regulating valve d25, opens the primary crystallizer compressed air inlet cut-off valve 36, pressurizes the chilled water in the primary crystallizer 108 to the 10-degree water storage tank of the public engineering, and the primary crystallizer compressed air inlet flowmeter 37 displays the inlet flow, and the flow rate is 300Nm when the water is steadily pressed. 3 When the water in the primary crystallizer 108 is drained, the compressed air flow rate will instantly rise to 550Nm 3 / h, at which time the system automatically closes the primary crystallizer compressed air inlet cut-off valve 36, the primary crystallizer drain cut-off valve 17, the primary crystallizer water inlet regulating valve a22, the primary crystallizer water inlet regulating valve b23, the primary crystallizer water inlet regulating valve c24 and the primary crystallizer water inlet regulating valve d25. A chilled water tank on-site vent line 38 is provided on the top of the chilled water tank 13 to prevent the chilled water tank 13 from overpressure or negative pressure when entering and exiting the water.

[0056] One crystallization sweating process: The one crystallization sweating time is about 16 hours. The volume of the sweating water tank 39 is designed to match the shell volume of all system crystallizers to meet the design requirements of sweating of the maximum number of crystallizers at the same time. When the system is running, the sweating water tank level gauge 41 is automatically detected first. When the liquid level is lower than 30%, the process water inlet regulating valve a40 is opened, and water replenishment is started to make the sweating water tank level gauge 41 reach 80%, and the process water inlet regulating valve a40 is automatically closed, the sweating water pump 45 is started, and the sweating water circulation regulating valve 47 is opened. The sweating water pump outlet pressure gauge 46 is automatically controlled, and the pressure setting value is 0.5mpa, in order to ensure that the temperature in the sweating water tank 39 is mixed evenly. The system automatically detects the reading of the sweating water tank thermometer 44. When it exceeds 22.1 degrees, the 10-degree water supply regulating valve 42 is automatically adjusted; when it is lower than 21.9 degrees, the sweating water tank steam regulating valve 43 is automatically adjusted. In order to save temperature control time, before the system is operated, the water is manually replenished to 80%, and then the temperature control program is put into use to keep the water tank temperature at 22 degrees. The system automatically detects the sweating water tank level gauge 41. When the liquid level is lower than 30%, the system suspends operation and resumes the program after the crystallizer sweating water is returned. This situation generally does not occur. The system detects that the sweating water tank level gauge 41 is greater than 30%, and the sweating water tank thermometer 44 is at 22±0.1 degrees, and opens the primary sweating tank feed cut-off valve 48, the primary crystallization sweating return water cut-off valve 50, the primary crystallization return water main valve 51 and the primary crystallization sweating water inlet cut-off valve 49; the primary crystallization water inlet regulating valve a 22 has a valve opening of 30%, the primary crystallization water inlet regulating valve b 23 has a valve opening of 30%, the primary crystallization water inlet regulating valve c 24 has a valve opening of 30%, the primary crystallization water inlet regulating valve d 25 has a valve opening of 30%, and opens the primary crystallization total water inlet regulating valve 20, and the primary crystallization total water inlet regulating valve 20 is automatically associated with the primary crystallization water inlet flowmeter 53, and the flow rate is set to 15t / h. Under this condition, the readings of the primary crystallizer thermometer a 26, primary crystallizer thermometer b 27, primary crystallizer thermometer c 28 and primary crystallizer thermometer d 29 in the primary crystallizer 108 will gradually increase. When the reading of one of the thermometers reaches 21.6 degrees, the setting value of the primary crystallization water inlet flowmeter 53 is changed to 10 t / h, the valve position of the primary crystallization water inlet regulating valve a 22 is changed to 13%, the valve position of the primary crystallization water inlet regulating valve b 23 is changed to 10%, the valve position of the primary crystallization water inlet regulating valve c 24 is changed to 6%, and the valve position of the primary crystallization water inlet regulating valve d 25 is changed to 2%. Under this condition, impurities will flow into the primary sweat tank 54 along with sweat; when the reading of the primary sweat tank weighing module 55 reaches 4t, sweating is completed, and the primary sweat tank feed cut-off valve 48 is closed.Before the next feeding of the primary raw material tank 2, first check the indication of the primary sweat tank weighing module 55. After confirming the presence of sweat, start the primary sweat pump 56, open the primary sweat pump outlet shut-off valve 57, and transport sweat to the primary raw material tank 2. When the indication of the primary sweat tank weighing module 55 is 0, close the primary sweat pump outlet shut-off valve 57, stop the primary sweat pump 56, and use the sweat as the next primary crystallization raw material.

[0057] The process of sweating water removal in the primary crystallization: the system automatically closes the primary crystallization sweating water inlet cut-off valve 49, closes the primary crystallization total water inlet regulating valve 20, closes the primary crystallization return water main valve 51, opens the primary crystallization secondary line cut-off valve 52, fully opens the primary crystallization water inlet regulating valve a22, primary crystallization water inlet regulating valve b23, primary crystallization water inlet regulating valve c24 and primary crystallization water inlet regulating valve d25, opens the primary crystallization compressed air inlet cut-off valve 36, and presses the sweating water in the primary crystallizer 108 into the sweating water tank 39. When the reading of the primary crystallizer compressed air flow meter 37 reaches 550Nm 3 / h, the system automatically closes the primary crystallizer compressed air inlet cut-off valve 36, the primary crystallization secondary line cut-off valve 52, the primary crystallization sweat water return cut-off valve 50, the primary crystallization secondary line cut-off valve 52, the primary crystallization water inlet regulating valve a22, the primary crystallization water inlet regulating valve b23, the primary crystallization water inlet regulating valve c24 and the primary crystallization water inlet regulating valve d25. The top of the sweating water tank 39 is provided with a sweating water tank on-site venting line 107, which is used to discharge the compressed air in time when the water is compressed to prevent the sweating water tank 39 from overpressure.

[0058] One crystallization process: One crystallization process takes about 1 hour, so the volume of the boiling water tank 62 can meet the volume required for one crystallizer. The system automatically detects the boiling water tank level gauge 59. When the liquid level reading is lower than 70%, the system automatically opens the process water inlet regulating valve b58 and starts to feed water into the boiling water tank 62. When the reading of the boiling water tank level gauge 59 reaches 70%, the process water inlet regulating valve b58 is closed, and the boiling water pump 63 is started. The boiling water return regulating valve 65 is automatically associated with the boiling water pump outlet pressure gauge 64, and the pressure setting value is 0.5 MPa to ensure the continuous and normal operation of the boiling water pump 63. The boiling water tank thermometer 60 is automatically associated with the boiling water tank steam regulating valve 61, and the setting value is 40 degrees. When it is lower than 40 degrees, steam heating is automatically passed. When it reaches 40 degrees, the boiling water tank steam regulating valve 61 is closed. After the system detects that the reading of the boiling water tank level gauge 59 is greater than 65% and the reading of the boiling water tank thermometer 60 is greater than 35 degrees, the system opens the primary crystallization return water cut-off valve 67, the primary crystallization return water total cut-off valve 51 and the primary crystallizer melting water inlet cut-off valve 66 in sequence. The valve position of the primary crystallization total water inlet regulating valve 20 is opened to 50%, and the valve positions of the primary crystallization water inlet regulating valve a22, the primary crystallization water inlet regulating valve b23, the primary crystallization water inlet regulating valve c24 and the primary crystallization water inlet regulating valve d25 are opened to 30%. This regulating valve position opening can maintain the reading of the boiling water tank thermometer 60 stable at 35-40 degrees. Too large an opening will cause the temperature of the boiling water tank 62 to be too low. When the readings of the primary crystallizer thermometer a 26, the primary crystallizer thermometer b 27, the primary crystallizer thermometer c 28 and the primary crystallizer thermometer d 29 in the primary crystallizer 108 all reach 30 degrees, the primary crystallization process is completed.

[0059] Primary crystallization degeneration boiling water process: the system automatically closes the primary crystallizer melting water inlet cut-off valve 66, the primary crystallization return water main valve 51 and the primary crystallization main water inlet regulating valve 20, opens the primary crystallization secondary line cut-off valve 52, the primary crystallization water inlet regulating valve a22, the primary crystallization water inlet regulating valve b23, the primary crystallization water inlet regulating valve c24 and the primary crystallization water inlet regulating valve d25 are fully opened, and the primary crystallization compressed air inlet cut-off valve 36 is opened to pressurize the boiling water in the primary crystallizer 108 to the boiling water tank 62; when the reading of the primary crystallizer compressed air inlet flowmeter 37 reaches 550Nm 3 / h, the system automatically closes the primary crystallizer compressed air inlet cut-off valve 36, the primary crystallization secondary line cut-off valve 52, the primary crystallization boiled water return cut-off valve 67, the primary crystallization water inlet regulating valve a22, the primary crystallization water inlet regulating valve b23, the primary crystallization water inlet regulating valve c24 and the primary crystallization water inlet regulating valve d25. The top of the boiled water tank 62 is provided with a boiled water tank on-site venting line 68, which is used to discharge the compressed air in time when the water is compressed to prevent the sweating water tank 62 from overpressure.

[0060] Primary crystallization degradation opening process: the system automatically detects the reading of the secondary raw material tank weighing module 70. When it is less than 1t, the primary crystallization discharge shut-off valve 73 is opened, and the vinylene carbonate with a purity of 99.95% in the primary crystallizer 108 enters the secondary raw material tank 69; when the reading of the secondary raw material tank weighing module 70 is greater than 22t, and it remains stable for three minutes without changing, the primary crystallization discharge shut-off valve 73 is closed.

[0061] Secondary raw material circulation process: the system automatically opens the secondary crystallization circulation shut-off valve 76, starts the secondary raw material circulation pump 74, and the system automatically detects the pump operating current. In the stage of excessive starting current, the secondary crystallizer feed regulating valve 75 is in a closed state. After the current stabilizes for 3 seconds, the secondary crystallizer feed regulating valve 75 gradually and automatically opens to 35% opening; when the opening is reached, it is automatically linked to the secondary crystallizer air intake flow meter 77 display data, and the set value is 16t / h. The secondary crystallizer feed regulating valve 75 automatically stabilizes at about 16t / h according to the value displayed by the secondary crystallizer air intake flow meter 77.

[0062] Secondary crystallization process: The system detects that the operation of the chilled water is normal. The detection conditions include that the operation signal and current display of the chilled water pump 7 are normal, and the chilled water tank thermometer 10 and the chilled water tank liquid level meter 12 are normal. At this time, the secondary crystallization instruction is executed, and the secondary crystallization chilled water return water cut-off valve 81, the secondary crystallization return water cut-off valve 84 and the secondary crystallization chilled water inlet water cut-off valve 111 are opened in sequence. The system automatically opens the secondary crystallization total water inlet regulating valve 94, and forms automatic control with the secondary crystallization water inlet flowmeter 36. The flow setting value is 30t / h. At this time, the opening of the chilled water return regulating valve 19 is 100%, and the 10-degree water return regulating valve 30 is closed. The purpose is to keep the chilled water tank liquid level slowly decreasing. At the same time, the temperature control runs automatically to maintain the temperature of the chilled water tank. According to the experience of multiple manual operation calibration, the output valve position of the secondary crystallization water inlet regulating valve a 86 is 61%, the output valve position of the secondary crystallization water inlet regulating valve b88 is 50%, the output valve position of the secondary crystallization water inlet regulating valve c 90 is 37%, and the output valve position of the secondary crystallization water inlet regulating valve d 92 is 23%. Under this valve position, the crystallization rate of vinylene carbonate is relatively fast. At the end of crystallization, the temperatures of secondary crystallizer thermometer a 85, secondary crystallizer thermometer b 87, secondary crystallizer thermometer c 89 and secondary crystallizer thermometer d 91 in secondary crystallizer 109 are similar. The analysis results after melting show that there are few crystallized impurities, proving that under this equipment operating condition, the output valve position is set to match the process. As 10-degree water enters, the liquid level of the chilled water tank will gradually rise. When the chilled water tank level meter 12 reaches 70%, the 10-degree water return regulating valve 30 is opened. The 10-degree water return regulating valve 30 is automatically associated with the 10-degree water return flowmeter 32. The chilled water tank inlet regulating valve 15 is automatically associated with the chilled water tank inlet flowmeter 31. At this time, the system instructs the chilled water tank inlet flowmeter 31 and the 10-degree water return flowmeter 32 to be equivalent, in order to ensure that the liquid level of the chilled water tank 13 is stable at 70%. At the same time, the chilled water tank inlet flowmeter 31 is automatically associated with the chilled water tank thermometer 10, in order to ensure that the temperature in the chilled water tank 13 is stable at 18 degrees. The chilled water return regulating valve 19 is automatically associated with the chilled water return flowmeter 35. The setting value logic of the chilled water return regulating valve 19 is the default 100% valve position when the crystallizer is put into use with chilled water; when the chilled water tank level meter 12 reaches 70%, another set of control logic is triggered. The control method is to automatically detect the crystallization state of the primary and secondary crystallizers, confirm the switch state of the primary crystallizer chilled water inlet cut-off valve 18 and the secondary crystallizer chilled water inlet cut-off valve 111; if it is in the open state, then the circulation flow rate of one way is 30t / h, and the two ways is 60t / h. The automatic setting value of the chilled water return flow meter 35 is the total circulation flow required for crystallization minus the display value of the chilled water tank inlet flow meter 31, so that the stable control of the chilled water tank liquid level can be achieved. During the secondary crystallization process, the vinylene carbonate in the secondary raw material tank 69 will gradually decrease. When the secondary raw material tank weighing module 70 displays a value of 3t, the secondary raw material crystallization is completed.Close the secondary crystallizer feed regulating valve 75, close the secondary raw material tank circulation cut-off valve 76 after three minutes, stop the secondary raw material circulation pump 74, and there are 3t of mother liquor remaining in the secondary raw material tank. After each primary crystallization raw material tank pumps out the remaining mother liquor to the upstream distillation unit, start the secondary raw material pump 74, open the delivery cut-off valve 78, and deliver the mother liquor to the primary raw material tank 2 to be used as the next primary crystallization raw material. Since the secondary crystallization cycle is shorter than the primary crystallization, there will be no conflict in system operation.

[0063] Secondary crystallization refrigeration water process: the system automatically closes the secondary crystallization chilled water inlet cut-off valve 111, the secondary crystallization total inlet regulating valve 94 and the secondary crystallization chilled water return cut-off valve 81, opens the secondary crystallization drain cut-off valve 93, fully opens the secondary crystallization inlet regulating valve a 86, the secondary crystallization inlet regulating valve b 88, the secondary crystallization inlet regulating valve c 90 and the secondary crystallization inlet regulating valve d 92, opens the secondary crystallizer compressed air inlet cut-off valve 80, pressurizes the chilled water in the secondary crystallizer 109 to the 10-degree water storage tank of the public engineering, and the secondary crystallizer compressed air inlet flowmeter 79 displays the inlet flow, and the flow rate is 300Nm when the water is steadily pressed. 3 When the water in the secondary crystallizer 109 is drained, the compressed air flow rate will instantly rise to 550Nm 3 / h, at this time the system automatically closes the secondary crystallizer compressed air inlet shut-off valve 80, the secondary crystallization drain shut-off valve 93, the secondary crystallization water inlet regulating valve a 86, the secondary crystallization water inlet regulating valve b 88, the secondary crystallization water inlet regulating valve c90 and the secondary crystallization water inlet regulating valve d92.

[0064] Secondary crystallization sweating process: The secondary crystallization sweating time is about 10 hours. The system detects that the sweating water tank liquid level gauge 41 is greater than 30%, and the sweating water tank thermometer 44 is at 22±0.1 degrees. Open the secondary sweat tank feed cut-off valve 96, the secondary crystallization sweating return water cut-off valve 82, the secondary crystallization return water cut-off valve 84 and the secondary crystallization sweat liquid inlet cut-off valve 98. The secondary crystallization total water inlet regulating valve 94 has a valve opening of 30%, the secondary crystallization water inlet regulating valve a 86 has a valve opening of 30%, the secondary crystallization water inlet regulating valve b 88 has a valve opening of 30%, the secondary crystallization water inlet regulating valve c 90 has a valve opening of 30%, the secondary crystallization water inlet regulating valve d 92 has a valve opening of 30%, and the secondary crystallization total water inlet regulating valve 94 is automatically associated with the secondary crystallization water inlet flowmeter 110, and the flow rate is set to 15t / h. Under this condition, the readings of secondary crystallizer thermometer a 85, secondary crystallizer thermometer b 87, secondary crystallizer thermometer c 89 and secondary crystallizer thermometer d 91 in the secondary crystallizer 109 will gradually increase; when the reading of one of the thermometers reaches 21.6 degrees, the set value of secondary crystallization water inlet flowmeter 110 is changed to 10t / h, the valve position of secondary crystallization water inlet regulating valve a 86 is changed to 10%, the valve position of secondary crystallization water inlet regulating valve b 88 is changed to 7%, the valve position of secondary crystallization water inlet regulating valve c 90 is changed to 4%, and the valve position of secondary crystallization water inlet regulating valve d 92 is changed to 1%. Under this condition, impurities will flow into the secondary sweat tank 71 along with the sweat; when the reading of the secondary sweat tank weighing module 72 reaches 2.5t, the system automatically alarms, and the on-site operator takes a sample at the sampling point 21 and sends it to the laboratory for analysis. The analysis result shows that the ethylene carbonate content is less than 99.995%. The sweating time is determined based on the analysis result, until the sampling analysis result shows that the ethylene carbonate content is greater than 99.995%, and the sweating is completed. The purpose of sample testing is to ensure that the product is qualified. The operator in the DCS clicks the secondary open button on the operation screen, and the system automatically closes the secondary sweat tank feed shut-off valve 96. Before the next feeding of the primary raw material tank 2, first check the indication of the secondary sweat tank weighing module 72. After confirming the presence of sweat, start the secondary sweat pump 101, open the primary sweat pump outlet shut-off valve 100, and transport sweat to the primary raw material tank 2; when the indication of the secondary sweat tank weighing module 72 is 0, close the secondary sweat pump outlet shut-off valve 100, stop the secondary sweat pump 101, and use the secondary sweat as the raw material for the next primary crystallization.

[0065] Secondary crystallization sweat water retreat process: the system automatically closes the secondary crystallization sweat water inlet cut-off valve 98, closes the secondary crystallization total water inlet regulating valve 94, closes the secondary crystallization return water cut-off valve 84, opens the secondary crystallization secondary line cut-off valve 99, fully opens the secondary crystallization water inlet regulating valve a 86, the secondary crystallization water inlet regulating valve b 88, the secondary crystallization water inlet regulating valve c 90 and the secondary crystallization water inlet regulating valve d 92, opens the secondary crystallizer compressed air inlet cut-off valve 80, and presses the sweat water in the secondary crystallizer 109 to the sweat water tank 39; when the reading of the secondary crystallizer compressed air inlet flowmeter 79 reaches 550Nm 3 / h, at this time the system automatically closes the secondary crystallizer compressed air inlet shut-off valve 80, the secondary crystallization side line shut-off valve 99, the secondary crystallization sweat water return shut-off valve 82, the secondary crystallization water inlet regulating valve a 86, the secondary crystallization water inlet regulating valve b 88, the secondary crystallization water inlet regulating valve c 90 and the secondary crystallization water inlet regulating valve d 92.

[0066] Secondary crystallization process: The secondary crystallization time is about 0.7 hours. After the system detects that the reading of the boiling water tank level gauge 59 is greater than 65% and the reading of the boiling water tank thermometer 60 is greater than 35 degrees, the system opens the secondary crystallization return water cut-off valve 83, the secondary crystallization return water cut-off valve 84 and the secondary crystallizer boiling water cut-off valve 97 in sequence, and the secondary crystallization total water inlet regulating valve 94 is opened to 50%, and the valve positions of the secondary crystallization water inlet regulating valve a 86, the secondary crystallization water inlet regulating valve b 88, the secondary crystallization water inlet regulating valve c 90 and the secondary crystallization water inlet regulating valve d92 are opened to 30%. This regulating valve position opening can maintain the reading of the boiling water tank thermometer 44 stable at 35-40 degrees. Too large an opening will cause the boiling water tank temperature to be too low. When the readings of the secondary crystallizer thermometer a 85, secondary crystallizer thermometer b 87, secondary crystallizer thermometer c 89 and secondary crystallizer thermometer d 91 in the secondary crystallizer 109 all reach 30 degrees, the secondary crystallization process is completed.

[0067] Secondary crystallization degraded water process: the system automatically closes the secondary crystallizer degraded water inlet cut-off valve 97, the secondary crystallization return water cut-off valve 84 and the secondary crystallization total water inlet regulating valve 94, opens the secondary crystallization secondary line cut-off valve 99, fully opens the secondary crystallization water inlet regulating valve a86, the secondary crystallization water inlet regulating valve b88, the secondary crystallization water inlet regulating valve c90 and the secondary crystallization water inlet regulating valve d92, opens the secondary crystallization compressed air inlet cut-off valve 80, and presses the degraded water in the secondary crystallizer 109 to the degraded water tank 62; when the reading of the secondary crystallizer compressed air inlet flowmeter 79 reaches 550Nm 3 / h, the system automatically closes the secondary crystallizer compressed air inlet cut-off valve 80, the secondary crystallization side line cut-off valve 99, the secondary crystallization return water cut-off valve 83, the secondary crystallization water inlet regulating valve a86, the secondary crystallization water inlet regulating valve b 88, the secondary crystallization water inlet regulating valve c 90 and the secondary crystallization water inlet regulating valve d92.

[0068] Secondary crystallization degradation opening process: When the system automatically detects that the reading of the melting tank weighing module 103 is less than 30t, the secondary crystallization discharge cut-off valve 95 is opened, and the vinylene carbonate with a purity of 99.999% in the secondary crystallizer 109 enters the melting tank 102; when the reading of the melting tank weighing module 103 is stable and does not change for three minutes, the secondary crystallization discharge cut-off valve 95 is closed. If the reading of the melting tank weighing module 103 is greater than 30t, the system will suspend the material return and issue an alarm. The workshop operator will start the melting pump 104 in time according to the progress of the packaging process to send the vinylene carbonate in the melting tank to the downstream to keep the system running continuously.

[0069] Crystallization heating process: When the reading of the melting tank level gauge 59 is greater than 20%, the heating circulation pump 106 can be activated to provide heating for the equipment pipeline 105 of the workshop crystallization unit.

[0070] The present invention collects data based on the manual operation of the operator, and then controls the entire crystallization process through the instrument automation program, which greatly reduces the requirements for the operator's operating proficiency, makes the process node control more accurate, avoids misoperation, and outputs products with higher efficiency and yield. By optimizing the shell structure of the crystallizer, the purpose of improving yield and efficiency can also be achieved. Through the secondment control of the chilled water tank and the 10-degree water storage tank of the public works, and the use of the boiling water tank water source for the equipment and pipeline hot water of the crystallization unit, the actual needs of the process are met, the equipment construction cost is greatly reduced, and the workshop space is saved.

[0071] The jacket of the primary and secondary crystallizers of the present invention is changed into a segmented jacket, and the jacket on the whole equipment is evenly distributed, so that the internal circulating medium is reduced and concentrated, and heating or cooling can be achieved more quickly, reducing the heating or cooling time and increasing the efficiency of heat transfer or cooling. A temperature sensor and an automatic regulating valve are added to the inlet and outlet of each section of the barrel jacket, and the value displayed by the temperature sensor is linked with the opening of the automatic regulating valve to control the temperature within the specified value range, and the temperature stability is more accurately guaranteed, so that the material can be purified once and for all, which improves the production capacity, reduces the material consumption, and saves the cost.

[0072] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A fully automatic control system for vinylene carbonate crystallization process, characterized in that: include: The primary crystallization module is used for the primary crystallization, primary sweating and primary melting process of vinylene carbonate semi-finished products; A secondary crystallization module is connected to the primary crystallization module, and is used to perform secondary crystallization, secondary sweating and secondary ablation processes on the vinylene carbonate solution output from the primary crystallization module; The temperature control module is connected with the primary crystallization module and the secondary crystallization module, and the temperature control module provides temperature control water for each process for the primary crystallization module and the secondary crystallization module respectively.

2. The fully automatic control system for vinylene carbonate crystallization process according to claim 1, characterized in that: The primary crystallization module comprises a primary raw material tank (2), a primary sweat tank (54) and a primary crystallizer (108), wherein the shell of the primary crystallizer (108) is a primary crystallization sandwich temperature control structure, and the primary crystallization sandwich temperature control structure is connected to the temperature control module; The bottom of the primary crystallizer (108) is connected to the primary raw material tank (2), the primary sweat tank (54) and the secondary crystallization module through three branch pipelines, and each branch pipeline is provided with a control valve; the primary sweat tank (54) is connected to the primary raw material feed port of the primary raw material tank (2) through a primary sweat pump (56) and a pipeline, and the primary raw material feed port is also connected to the vinyl carbonate semi-finished product feed line. The primary raw material tank (2) is connected to the top of the primary crystallizer (108) and the upstream distillation unit through a primary raw material circulation pump (4) and a primary crystallization circulation pipeline, and each pipeline is provided with a control valve.

3. The fully automatic control system for vinylene carbonate crystallization process according to claim 2, characterized in that: The secondary crystallization module comprises a secondary raw material tank (69), a secondary sweat tank (71), a melting tank (102) and a secondary crystallizer (109), wherein the shell of the secondary crystallizer (109) is a secondary crystallization sandwich temperature control structure, and the secondary crystallization sandwich temperature control structure is connected to the temperature control module; The bottom of the secondary crystallizer (109) is connected to the secondary raw material tank (69), the secondary sweat tank (71) and the melting tank (102) through three branch pipelines, and each branch pipeline is provided with a control valve; the secondary raw material tank (69) is connected to the top of the secondary crystallizer (109) through a secondary raw material circulation pump (74) and a secondary raw material circulation pipeline, the secondary sweat tank (71) is connected to the primary raw material tank (2) through a secondary sweat pump (101) and a pipeline, and the melting tank (102) is connected to the finished product line through a melting pump (104).

4. The fully automatic control system for vinylene carbonate crystallization process according to claim 3, characterized in that: The primary crystallization interlayer temperature control structure of the primary crystallizer (108) is the same as the secondary crystallization interlayer temperature control structure of the secondary crystallizer (109), both of which include multiple sections of jackets with independent cavities arranged in sequence along the height direction, and the inlet and outlet of each section of the jacket are respectively provided with a temperature sensor and an automatic regulating valve, and the value displayed by the temperature sensor is interlocked with the opening of the automatic regulating valve.

5. The fully automatic control system for vinylene carbonate crystallization process according to claim 3, characterized in that: The primary raw material tank (2) is provided with a raw material tank weighing module (3) for weighing the raw material; and the secondary raw material tank (69) is provided with a secondary raw material tank weighing module (70) for weighing the secondary raw material.

6. The fully automatic control system for vinylene carbonate crystallization process according to claim 1, characterized in that: The temperature control module includes a chilled water control module, a sweating water control module and a boiling water control module; The primary crystallizer (108) is connected to a chilled water control module, a sweating water control module and a boiling water control module to form a primary chilled water circulation system, a primary sweating water circulation system and a primary boiling water circulation system; The secondary crystallizer (109) is connected to the chilled water control module, the sweating water control module and the boiling water control module to form a secondary chilled water circulation system, a secondary sweating water circulation system and a secondary boiling water circulation system; The return pipelines of the primary crystallizer (108) and the secondary crystallizer (109) are connected to the compressed air pipeline, and the frozen water, sweat water and boiled water are compressed back by compressed air.

7. The fully automatic control system for vinylene carbonate crystallization process according to claim 6, characterized in that: The chilled water control module comprises a chilled water tank (13) and a chilled water pump (7), wherein the water inlet of the chilled water pump (7) is connected to the bottom of the chilled water tank (13), and the water outlet of the chilled water pump (7) is respectively connected to the top of the chilled water tank (13), the primary crystallizer (108), the secondary crystallizer (109) and the return water main through a plurality of branch pipelines, and a control valve is provided on each branch pipeline; the primary crystallizer (108) and the secondary crystallizer (109) are connected to the top of the chilled water tank (13) through a chilled water return pipeline; and the top of the chilled water tank (13) is connected to a 10°C water inlet pipeline.

8. The fully automatic control system for vinylene carbonate crystallization process according to claim 6, characterized in that: The sweating water control module comprises a sweating water tank (39) and a sweating water pump (45), wherein the water inlet of the sweating water pump (45) is connected to the bottom of the sweating water tank (39) through a pipeline, and the water outlet of the sweating water pump (45) is connected to the top of the sweating water tank (39), the primary crystallizer (108) and the secondary crystallizer (109) through a plurality of branch pipelines, and each branch pipeline is provided with a control valve; the primary crystallizer (108) and the secondary crystallizer (109) are connected to the top of the sweating water tank (39) through a sweating water return pipeline; and the top of the sweating water tank (39) is connected to the process water inlet pipeline.

9. The fully automatic control system for vinylene carbonate crystallization process according to claim 6, characterized in that: The boiling water control module comprises a boiling water tank (62) and a boiling water pump (63), wherein the water inlet of the boiling water pump (63) is connected to the bottom of the boiling water tank (62), and the water outlet of the boiling water pump (63) is respectively connected to the top of the boiling water tank (62), the primary crystallizer (108) and the secondary crystallizer (109) through a plurality of branch pipelines, and each branch pipeline is provided with a control valve; the primary crystallizer (108) and the secondary crystallizer (109) are connected to the top of the boiling water tank (62) through a boiling water return pipeline; and the top of the boiling water tank (62) is connected to a process water inlet pipeline.

10. The fully automatic control system for vinylene carbonate crystallization process according to claim 6, characterized in that: The temperature of the freezing water is 17-18°C, the temperature of the sweating water is 20-22°C, and the temperature of the boiling water is 35-40°C.

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