Crude vinyl chloride alkali washing device
By designing an alkaline washing tower and an alkaline liquid collector, the system achieves thorough mixing of alkaline liquid and vinyl chloride and captures residual alkaline liquid, solving the corrosion and clogging problems caused by uneven alkaline washing in existing technologies, and improving the stability and economic efficiency of the production unit.
Patent Information
- Application Number
- CN202423162714.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-20
AI Technical Summary
The existing alkaline washing unit for crude vinyl chloride purification suffers from uneven mixing of alkaline solution and water during periodic flushing operations, resulting in incomplete absorption of acidic gases, corrosion of subsequent system pipelines and equipment, and crystallization of residual alkaline solution in vinyl chloride after alkaline washing, which blocks the pipelines and affects the operation of the production unit.
A device comprising an alkaline washing tower, a pipeline mixer, a circulating alkaline solution pump, and an alkaline solution collector was designed. Through countercurrent contact and circulating water cooling, the alkaline solution is ensured to be fully mixed with vinyl chloride, residual alkaline solution is collected, and the concentration and flow rate of the alkaline solution are adjusted in real time by pH and liquid level detection to achieve stable control of the alkaline washing effect.
It effectively removes residual alkaline solution from vinyl chloride, avoids equipment corrosion and crystallization blockage, improves the operational stability and continuity of the production unit, and reduces operating costs.
Smart Images
Figure CN223602315U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of vinyl chloride purification, specifically to a caustic washing device for crude vinyl chloride purification. BACKGROUND
[0002] In order to prepare high-purity vinyl chloride monomer, while avoiding the corrosion of the equipment and valves in the subsequent system caused by the acidic gas mainly composed of hydrogen chloride in the vinyl chloride gas, the method of "water washing + caustic washing" is usually used in the industrial production process to completely remove the acidic gas mainly composed of hydrogen chloride in the vinyl chloride gas.
[0003] In the continuous operation process of the production device in the prior art, the periodic flushing and caustic solution preparation operations of the caustic washing device for crude vinyl chloride purification are manually operated, which is complicated and tedious, and the high-concentration caustic solution and water are not fully mixed. In addition, due to the neutral position of the caustic washing device during the periodic flushing operation, the absorption of acidic gas is not complete, which causes the corrosion of the pipelines and equipment in the subsequent system. Moreover, due to the presence of trace caustic solution in the vinyl chloride after caustic washing, crystallization occurs in the pipelines and equipment in the subsequent system due to the decrease in temperature, which causes blockage and corrosion of the pipelines and equipment, and finally leads to a decrease in the operation load of the production device or even forced shutdown for maintenance. SUMMARY
[0004] To solve the technical problem of residual caustic solution after caustic washing of vinyl chloride by the caustic washing device for crude vinyl chloride purification in the prior art, the utility model provides a caustic washing device for crude vinyl chloride.
[0005] The caustic washing device for crude vinyl chloride includes a caustic washing tower, a pipeline mixer, and a circulating caustic solution pump. The caustic solution outlet of the caustic washing tower is connected to the liquid inlet of the circulating caustic solution pump. The liquid outlet of the circulating caustic solution pump is connected to the caustic solution inlet of the caustic washing tower through a circulating caustic solution pipeline. The liquid outlet of the pipeline mixer is connected to the circulating caustic solution pipeline. The device further includes a caustic solution trap, wherein the caustic solution trap is connected to the circulating caustic solution pipeline through a caustic solution trapping pipeline. The top of the caustic washing tower is connected to the caustic solution trap through a vinyl chloride outlet pipeline.
[0006] The caustic washing device for crude vinyl chloride further includes a circulating water cooling pipeline, wherein the circulating water cooling pipeline is arranged outside the caustic solution trap.
[0007] The caustic washing device for crude vinyl chloride includes a caustic washing tower, a pipeline mixer, and a circulating caustic solution pump. The caustic solution outlet of the caustic washing tower is connected to the liquid inlet of the circulating caustic solution pump. The liquid outlet of the circulating caustic solution pump is connected to the caustic solution inlet of the caustic washing tower through a circulating caustic solution pipeline. The liquid outlet of the pipeline mixer is connected to the circulating caustic solution pipeline. The device further includes a caustic solution trap, wherein the caustic solution trap is connected to the circulating caustic solution pipeline through a caustic solution trapping pipeline. The top of the caustic washing tower is connected to the caustic solution trap through a vinyl chloride outlet pipeline.
[0008] The first layer of tower plates of the tower plate section and the top of the filler section of the caustic washing device for crude vinyl chloride are both provided with liquid distributors.
[0009] The crude chloroethylene caustic washing device, the liquid storage section is provided with a pH detection device and a liquid level detection device, the circulating alkali liquor pipeline is connected with the circulating alkali liquor extraction pipeline through a circulating alkali liquor extraction regulating valve, and the pH detection device, the liquid level detection device and the circulating alkali liquor extraction regulating valve are connected with an upper control system.
[0010] The crude chloroethylene caustic washing device, the pipeline mixer adopts a static mixer, the pipeline mixer comprises a liquid inlet end and a liquid mixing section, the liquid inlet end is connected with a pure water pipeline and a high-concentration alkali liquor pipeline, and the liquid mixing section is connected with the circulating alkali liquor pipeline through a pipeline at the end.
[0011] The crude chloroethylene caustic washing device, the pure water pipeline and the high-concentration alkali liquor pipeline are provided with flow meters and flow regulating valves, and the flow meters and the flow regulating valves are connected with an upper control system.
[0012] The crude chloroethylene caustic washing device, the alkali liquor outlet of the caustic washing tower is also connected with a discharge pipeline, a discharge control valve is arranged on the discharge pipeline, and the discharge control valve is connected with an upper control system.
[0013] The crude chloroethylene caustic washing device, the alkali liquor outlet of the caustic washing tower is also connected with a discharge pipeline, a discharge control valve is arranged on the discharge pipeline, and the discharge control valve is connected with an upper control system. BRIEF DESCRIPTION OF DRAWINGS
[0014] Fig. 1 It is a structural schematic view of the crude chloroethylene caustic washing device.
[0015] Fig. 2 It is a structural schematic view of one of the alkali liquor collectors in the crude chloroethylene caustic washing device.
[0016] Fig. 3 It is a structural schematic view of one of the caustic washing towers in the crude chloroethylene caustic washing device.
[0017] Fig. 4 It is a structural schematic view of one of the pipeline mixers in the crude chloroethylene caustic washing device.
[0018] The figure is marked: 1-alkali washing tower, 101-ta board section, 102-packing section, 103-liquid storage section, 10301-pH detection device, 10302-liquid level detection device, 2-pipeline mixer, 201-liquid inlet end, 202-mixed liquid section, 3-circulating alkali pump, 4-circulating alkali pipeline, 401-circulating alkali production regulating valve, 5-alkali trap, 501-circulating water cooling pipeline, 502-trap body, 6-trapped alkali pipeline, 7-rough chloroethylene import pipeline, 8-chloroethylene export pipeline, 9-circulating alkali production pipeline, 10-pure water pipeline, 11-high concentration alkali pipeline, 12-flow meter, 13-flow regulating valve, 14-drainage pipeline, 1401-drainage control valve DETAILED DESCRIPTION
[0019] The utility model is described below in combination with the drawings.
[0020] As Figs. 1-4 The utility model rough chloroethylene alkali washing device, including alkali washing tower 1, pipeline mixer 2, circulating alkali pump 3, the alkali outlet of alkali washing tower 1 is connected with the liquid inlet of circulating alkali pump 3, the liquid outlet of circulating alkali pump 3 is connected to the alkali inlet of alkali washing tower 1 through circulating alkali pipeline 4, the liquid outlet of pipeline mixer 2 is connected with circulating alkali pipeline 4, and rough chloroethylene is first absorbed in the acid gas contained in alkali washing tower 1, in this embodiment, the proportion of high concentration alkali and pure water in pipeline mixer 2 needs to be adjusted, so that the pH in alkali washing tower 1 is kept between 9 and 10, avoiding that the acid gas in rough chloroethylene is not removed and is brought into subsequent pipelines and equipment due to the failure of circulating alkali, further including alkali trap 5 (herein trapping means capturing and collecting), wherein alkali trap 5 is connected to circulating alkali pipeline 4 through trapped alkali pipeline 6, the top of alkali washing tower 1 is connected with alkali trap 5 through chloroethylene export pipeline 8, and the rough chloroethylene after impurity removal in alkali washing tower 1 then enters alkali trap 5 to absorb the small amount of alkali entrained in rough chloroethylene, and finally is collected into trapped alkali pipeline 6 and finally enters circulating alkali pipeline 4, and the fresh alkali from pipeline mixer 2 is jointly introduced into alkali washing tower 1.
[0021] Further, alkali trap 5 includes circulating water cooling pipeline 501 and trap body 502, circulating water cooling pipeline 501 is arranged outside trap body 502, wherein trap body 502 adopts one of the technical solutions of the existing technology, trap body 502 is cooled by circulating water cooling pipeline 501, the alkali entrained in rough chloroethylene in trap body 502 is cooled and condensed and collected, and finally is collected into trapped alkali pipeline 6.
[0022] Further, the alkali washing tower 1 comprises a tray section 101, a filler section 102 and a storage section 103 from top to bottom, the tray section 101 is used to distribute the alkali solution and expand the contact area between the alkali solution and the crude vinyl chloride; the filler section 102 is filled with various filling materials, common filling materials include ceramic balls, ring tower fillers, corrugated fillers, etc., which are mainly used to reduce the gas-liquid flow rate, increase the gas-liquid contact area, and make the liquid phase flow through the gas phase better; the storage section 103 is mainly used to store the circulating alkali solution, the circulating alkali solution in the storage section 103 finally flows to the circulating alkali solution pump 3 through the alkali solution outlet at the bottom, the crude vinyl chloride inlet pipeline 7 is connected to the upper half of the side wall of the storage section 103, and the circulating alkali solution pipeline 4 outlet is connected to the side wall above the tray section 101, so that the alkali solution in the alkali washing tower 1 flows from top to bottom and the crude vinyl chloride flows from bottom to top, thereby making the circulating alkali solution and the crude vinyl chloride fully contact in countercurrent, and fully removing the acidic gas in the crude vinyl chloride.
[0023] Further, the first layer of the tray section 101 and the top of the filler section 102 are both provided with liquid distributors, so that the contact between the alkali solution and the crude vinyl chloride is more sufficient, and the removal effect of the acidic gas in the crude vinyl chloride is ensured.
[0024] Further, the storage section 103 is provided with a pH detection device 10301 and a liquid level detection device 10302 for detecting the pH value of the circulating alkali solution and the liquid level parameter of the storage section 103 respectively, the circulating pressure reducing pipeline 4 is connected to the circulating alkali solution extraction pipeline 9 through the circulating alkali solution extraction adjusting valve 401, the pH detection device 10301, the liquid level detection device 10302 and the circulating alkali solution extraction adjusting valve 401 are connected to the upper control system, the collected pH value of the circulating alkali solution and the liquid level parameter of the circulating alkali solution in the storage section are fed back to the upper control system in real time, and the system adjusts the opening degree of the extraction adjusting valve 401 according to the parameters in real time, so as to ensure that the liquid level and the pH value in the storage section are constant.
[0025] Further, the pipeline mixer 2 adopts a static mixer, the pipeline mixer 2 comprises a liquid inlet end 201 and a liquid mixing section 202, the liquid inlet end 201 is connected with a pure water pipeline 10 and a high-concentration alkali solution pipeline 11, and the end of the liquid mixing section 202 is connected to the circulating alkali solution pipeline 4 through a pipeline, so that the specified concentration of alkali solution can be stably output to the circulating alkali solution pipeline 4.
[0026] Further, the pure water pipeline 10 and the high-concentration alkali solution pipeline 11 are both provided with a flow meter 12 and a flow adjusting valve 13, the flow meter 12 and the flow adjusting valve 13 are connected to the upper control system, and the opening degree of the flow adjusting valve 13 can be adjusted by the technical personnel according to the data returned by the flow meter 12 in a pre-set parameter or real-time manual adjustment mode through the control system, so as to adjust the concentration of the alkali solution entering the circulating alkali solution pipeline 4.
[0027] Further, the alkali liquor outlet of the alkali washing tower 1 is also connected with the drain line 14, and the drain line 14 is provided with a drain control valve 1401 connected with the upper control system.
[0028] In the embodiment, first, the outputs of the pure water pipeline 10 and the high-concentration alkali liquor pipeline 11 are balanced by the pipeline mixer 2, so that alkali liquor of a specified concentration enters the circulating alkali liquor pipeline 4, and then the alkali liquor enters the tray section 101 in the alkali washing tower 1 through the alkali liquor inlet of the alkali washing tower 1, and then is uniformly sprayed in the alkali washing tower 1 through the liquid distributors installed at the first layer of the tray section 101 and the top of the filler section 102, while the material to be alkali washed enters the storage section 103 through the crude vinyl chloride inlet pipeline 7 on the upper half of the side wall of the storage section 103, and after fully contacting with the sprayed alkali liquor in the rising process, is transported to the alkali liquor catcher 5 through the alkali liquor mixed vinyl chloride outlet pipeline 8 at the top of the alkali washing tower 1, and after being cooled by the circulating water cooling pipeline 501 in the alkali liquor catcher 5, the alkali liquor in the vinyl chloride is condensed and collected at the bottom of the catcher body 502, and is transported to the circulating alkali liquor pipeline 4 through the alkali liquor catching pipeline 6, and the impurity-removed vinyl chloride is sent to the next process through the pipeline at the top of the alkali liquor catcher 5. The alkali liquor after the alkali washing treatment of the crude vinyl chloride is accumulated in the storage section 103, and the liquid level is higher than the crude vinyl chloride inlet pipeline 7, so that the crude vinyl chloride can be preliminarily alkali washed, and then the accumulated alkali liquor enters the circulating alkali liquor pipeline 4 from the alkali washing tower 1 and is combined with the alkali liquor output by the pipeline mixer 2. The skilled person can adjust the opening degree of the flow regulating valve 13 according to the data returned by the pH detection device 10301 and the liquid level detection device 10302 installed at the storage section 103 of the alkali washing tower 1, the flow meter 12 on the pure water pipeline 10 and the high-concentration alkali liquor pipeline 11, so as to maintain the pH in the circulating alkali liquor pipeline 4 stable, and in the embodiment, the pH needs to be controlled between 9 and 10, so as to avoid that the circulating alkali liquor cannot play the alkali washing effect and the acidic gas in the crude vinyl chloride cannot be removed and is brought into the subsequent pipelines and equipment. In the embodiment, the liquid level in the storage section 103 needs to be controlled at 50%±10% of the volume of the alkali washing tower 1, which is realized by controlling the opening degree of the drain control valve 1401 on the drain line 14, and the data output ends of the above-mentioned circulating alkali liquor production regulating valve 401, the flow regulating valve 13, the drain control valve 1401, the circulating alkali liquor pump 3, the pipeline mixer 2, the pH detection device 10301, the liquid level detection device 10302 and the flow meter 12 are connected with the DCS system, so as to realize the continuous steady-state operation of the device in a program logic control manner, which greatly reduces the operation cost.
[0029] Compared with the prior art, the alkali washed vinyl chloride is led to the alkali liquor catcher, the alkali liquor mixed in the vinyl chloride is collected by condensation and recycled, and the technical problem that alkali liquor is left after the alkali washing device for crude vinyl chloride purification in the prior art performs alkali washing on the vinyl chloride is solved.
Claims
1. A device for caustic washing of crude vinyl chloride, comprising a caustic washing tower (1), a pipeline mixer (2), a circulating caustic pump (3), the caustic outlet of the caustic washing tower (1) being connected to the liquid inlet of the circulating caustic pump (3), the liquid outlet of the circulating caustic pump (3) being connected to the caustic inlet of the caustic washing tower (1) through a circulating caustic pipeline (4), the liquid outlet of the pipeline mixer (2) being connected to the circulating caustic pipeline (4), characterized in that: Further comprising a lye trap (5) connected to the circulating lye pipeline (4) through a lye pipeline (6), and the top of the caustic washing tower (1) is connected to the lye trap (5) through a vinyl chloride outlet pipeline (8).
2. A crude vinyl chloride caustic scrubbing apparatus according to claim 1, characterized by: The lye trap (5) comprises a circulating water cooling pipeline (501) and a trap body (502), and the circulating water cooling pipeline (501) is arranged outside the trap body (502).
3. The crude vinyl chloride caustic scrubbing apparatus according to claim 1, characterized by: The caustic washing tower (1) comprises a tray section (101), a packing section (102) and a storage section (103) from top to bottom, the top half of the side wall of the storage section (103) is connected with a crude vinyl chloride inlet pipeline (7), and the circulating lye pipeline (4) is connected to the side wall above the tray section (101).
4. A crude vinyl chloride caustic scrubbing apparatus according to claim 3, wherein: The first layer of the tray section (101) and the top of the packing section (102) are both provided with a liquid distributor.
5. The crude vinyl chloride caustic scrubbing apparatus according to claim 3, characterized by: The storage section (103) is provided with a pH detection device (10301) and a liquid level detection device (10302), the circulating lye pipeline (4) is connected to a circulating lye production pipeline (9) through a circulating lye production regulating valve (401), and the pH detection device (10301), the liquid level detection device (10302) and the circulating lye production regulating valve (401) are all connected to an upper control system.
6. The crude vinyl chloride caustic scrubbing apparatus according to claim 1, characterized by: The pipeline mixer (2) adopts a static mixer, and comprises an inlet end (201) and a mixing section (202), the inlet end (201) is connected with a pure water pipeline (10) and a high-concentration lye pipeline (11), and the mixing section (202) is connected to the circulating lye pipeline (4) through a pipeline at the end.
7. A crude vinyl chloride caustic scrubbing apparatus according to claim 6, wherein: The pure water pipeline (10) and the high-concentration lye pipeline (11) are both provided with a flow meter (12) and a flow regulating valve (13), and the flow meter (12) and the flow regulating valve (13) are both connected to the upper control system.
8. The crude vinyl chloride caustic scrubbing apparatus according to claim 1, wherein: The lye outlet of the caustic washing tower (1) is also connected to a discharge pipeline (14), the discharge pipeline (14) is provided with a discharge control valve (1401), and the discharge control valve (1401) is connected to the upper control system.