Dimethyldichlorosilane Hydrolysis Product Separation System

Abstract

The present application provides a separation system for hydrolysis products of dimethyldichlorosilane, comprising: a hydrolysis reactor, a rough separator, a fine separator, a water washing tank and a separator connected in sequence. A first liquid level transmitter is arranged inside the rough separator, and a second liquid level transmitter is arranged inside the fine separator; the tops of the rough separator and the fine separator are connected through a gas-phase equilibrium pipe, and the bottoms of the rough separator and the fine separator are connected through a first aqueous phase conveying pipeline; the inlet of the circulation pump is connected to the aqueous phase outlet of the separator through a second aqueous phase conveying pipeline, and the outlet of the circulation pump is connected to the hydrolysis reactor; the second aqueous phase conveying pipeline is also connected to the first aqueous phase conveying pipeline; the make-up water pipeline is connected to the second aqueous phase conveying pipeline through a regulating valve. The separation system for hydrolysis products of dimethyldichlorosilane in the present application enables more precise control of the oil-water interface, increases the oil-water separation efficiency, greatly reduces the chloride ion content in the hydrolysis products, and reduces the viscosity of the hydrolysis products of dimethyldichlorosilane.

Description

Technical Field

[0001] This application relates to the technical field of organic chemical engineering, and particularly relates to a separation system for hydrolysis products of dimethyldichlorosilane. Background Art

[0002] The hydrolysis products of dimethyldichlorosilane are the most important intermediates in the silicone industry, serving as the basic raw materials for synthesizing silicone products such as silicone oil, silicone rubber, and silicone resin. Compared with the general process of first cracking and rectifying the hydrolysis products into DMC or cyclic bodies and then further synthesizing silicone products such as silicone oil, silicone rubber, and silicone resin used by major domestic and foreign manufacturers, not only is the process flow simple and the operation convenient, but also the energy consumption and material consumption are significantly reduced, eliminating the loss of dimethyl hydrolysis products during the cracking process, and demonstrating the cost advantage of the hydrolysis products of dimethyldichlorosilane.

[0003] Manufacturers usually use the concentrated acid hydrolysis method to hydrolyze dimethyldichlorosilane, and the generated hydrolysis products are a mixture of linear and cyclic oligomeric siloxanes and hydrogen chloride. At the same time, the hydrolysis products also contain a large amount of hydrochloric acid. The oil-water separation of the generated hydrolysis products is carried out to remove the hydrochloric acid in the hydrolysis products. However, in the prior art, the control of the oil-water interface is not precise enough, and the oil-water separation efficiency is low, resulting in the presence of chloride ion impurities in the finished product of the hydrolysis products of dimethyldichlorosilane. The high residual chlorine in the hydrolysis products will cause the viscosity of the hydrolysis products to be unstable, directly affecting the production of subsequent products and increasing the production cost. At the same time, the residual chlorine in the hydrolysis products is not conducive to the storage and transportation of the hydrolysis products, and the high acid value will corrode the equipment pipeline, affecting the quality of subsequent products. Therefore, removing chloride ions and other impurities from the hydrolysis products has very important practical significance. Summary of the Invention

[0004] This application provides a separation system for hydrolysis products of dimethyldichlorosilane to solve the problems in the prior art that the control of the oil-water interface of the hydrolysis products of dimethyldichlorosilane is not precise enough, the oil-water separation efficiency is low, and the chloride ion content in the hydrolysis products is relatively high.

[0005] This application provides a separation system for hydrolysis products of dimethyldichlorosilane, including: a hydrolysis reactor, a rough separation tank, a fine separation tank, a water washing tank, and a separator connected in sequence. A first liquid level transmitter is arranged inside the rough separation tank, and a second liquid level transmitter is arranged inside the fine separation tank.

[0006] The tops of the rough separation tank and the fine separation tank are connected through a gas-phase balance pipe, and the bottoms of the rough separation tank and the fine separation tank are connected through a first aqueous phase conveying pipeline.

[0007] The system is also provided with a circulation pump. The inlet of the circulation pump is connected to the aqueous phase outlet of the separator through a second aqueous phase conveying pipeline, and the outlet of the circulation pump is connected to the hydrolysis reactor.

[0008] The second aqueous phase transfer pipeline is also connected to the first aqueous phase transfer pipeline.

[0009] The system is also provided with a make-up water pipeline, and the make-up water pipeline is connected to the second aqueous phase transfer pipeline through a regulating valve.

[0010] The hydrolysis reactor is used for hydrolyzing dimethyldichlorosilane.

[0011] The rough separator and the fine separator are used for separating oil and water from the hydrolysis product of dimethyldichlorosilane.

[0012] The water washing tank is used for washing soluble impurities in the hydrolysis product of dimethyldichlorosilane.

[0013] The separator is used for separating the mixture after being washed by the water washing tank.

[0014] The gas-phase balance pipe is used for keeping the liquid level pressure of the rough separator and the fine separator stable.

[0015] The circulation pump is used for transporting the aqueous phase separated from the rough separator, the fine separator and the separator and the liquid in the make-up water pipeline to the hydrolysis reactor.

[0016] Optionally, the system is also provided with an interface control device, and the interface control device includes a second liquid level transmitter, a regulator and a regulating valve, and the regulator is connected between the second liquid level transmitter and the regulating valve.

[0017] Optionally, the oil-water interface of the rough separator and the fine separator is controlled at 20%-80% of the liquid level range.

[0018] Optionally, a stirring device is arranged in the water washing tank, and the stirring device includes a motor, a stirring shaft and a plurality of stirring components. The motor is rotationally connected to one end of the stirring shaft, and the plurality of stirring components are equidistantly installed along the height direction of the stirring shaft.

[0019] Optionally, a mounting frame is fixedly arranged at the top of the water washing tank, the motor is arranged at the top of the mounting frame, and the stirring shaft passes through the mounting frame and is rotationally connected to the motor.

[0020] Optionally, the stirring component includes three stirring arms, one ends of the three stirring arms are fixedly arranged at the same position of the stirring shaft, and stirring blades are welded to the other ends of the three stirring arms.

[0021] Optionally, among the three stirring arms of the stirring component, the included angle between adjacent stirring arms is 120°.

[0022] Optionally, at least one of the stirring arms in the stirring component is inclined upward or downward relative to the horizontal plane, and the inclination directions of adjacent stirring arms are opposite.

[0023] Optionally, a baffle plate is further arranged in the water washing tank, and a plurality of baffle plates are fixedly arranged along the inner wall of the water washing tank.

[0024] Optionally, the cross-sectional shape of the baffle plate is one of a quadrilateral, a triangle, and at least one side being arc-shaped.

[0025] The dimethyldichlorosilane hydrolysis product separation system provided by the present application realizes the separation of dimethyldichlorosilane hydrolysis products, and has the following beneficial effects:

[0026] (1) By arranging a rough stratifier and a fine stratifier, the hydrolysis products are subjected to multiple oil-water separations, making the oil-water interface stratification more thorough and the interface control more precise, which is beneficial to the separation of chloride ions in the hydrolysis products. A water washing tank is also arranged to further wash the chloride ions in the hydrolysis products, greatly reducing the chloride ion content in the hydrolysis products, thereby reducing the viscosity of the hydrolysis products and improving the quality of the hydrolysis products.

[0027] (2) By transporting the aqueous phase (dilute hydrochloric acid solution) in the rough stratifier, the fine stratifier, and the separator to the hydrolysis reactor as a supplementary water source, resources are saved, and at the same time, the discharge of waste acid is greatly reduced, having good economic and environmental benefits.

[0028] (3) By arranging an interface control device to control the amount of makeup water entering the hydrolysis reactor in the makeup water pipeline and maintain the balance of the oil-water interface in the rough stratifier and the fine stratifier, the oil-water interface control is made more accurate, thereby enabling the hydrolysis products and dilute hydrochloric acid to quickly stratify and reducing the viscosity of the hydrolysis products. The interface control device automatically completes the makeup water, reducing the number of operators and improving the environmental safety.

[0029] (4) The water washing tank is provided with a stirring device, wherein at least one stirring arm in the stirring assembly is inclined upward or downward relative to the horizontal plane, and the inclination directions of adjacent stirring arms are opposite. At the same time, a baffle plate is also arranged in the water washing tank, making the hydrolysis products and water mix more evenly, improving the efficiency of chloride ions and other impurities dissolving in water, and further reducing the chloride ion content in the hydrolysis products. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 It is a structural block diagram of a dimethyldichlorosilane hydrolysis product separation system provided by an embodiment of the present application;

[0032] Figure 2 Structural schematic diagram of the interface control device for the dimethyldichlorosilane hydrolysis product separation system provided by an embodiment of the present application;

[0033] Figure 3 Structural schematic diagram of the water washing tank of the dimethyldichlorosilane hydrolysis product separation system provided by another embodiment of the present application.

[0034] Description of the reference numerals:

[0035] 1: Hydrolysis reactor;

[0036] 2: Coarse layer separator;

[0037] 21: First liquid level transmitter;

[0038] 3: Fine layer separator;

[0039] 31: Second liquid level transmitter;

[0040] 4: Water washing tank;

[0041] 41: Motor;

[0042] 42: Stirring shaft;

[0043] 43: Stirring arm;

[0044] 44: Stirring blade;

[0045] 45: Mounting frame;

[0046] 46: Baffle plate;

[0047] 5: Separator;

[0048] 6: Gas phase balance pipe;

[0049] 7: First aqueous phase conveying pipeline;

[0050] 8: Second aqueous phase conveying pipeline;

[0051] 9: Circulation pump;

[0052] 10: Makeup water pipeline;

[0053] 11: Control valve;

[0054] 12: Interface control device;

[0055] 121: Regulator. Detailed implementation manners

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following clearly and completely describes the technical solutions in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts also belong to the scope of protection of this application.

[0057] Figure 1 The following is a structural block diagram of a dimethyldichlorosilane hydrolysis product separation system provided in an embodiment of this application. As Figure 1 shown, this application provides a dimethyldichlorosilane hydrolysis product separation system, including: a hydrolysis reactor 1, a rough layer separator 2, a fine layer separator 3, a water washing tank 4, and a separator 5 that are connected in sequence. A first liquid level transmitter 21 is arranged inside the rough layer separator 2, and a second liquid level transmitter 31 is arranged inside the fine layer separator 3.

[0058] The tops of the rough layer separator 2 and the fine layer separator 3 are connected through a gas phase balance pipe 6, and the bottoms of the rough layer separator 2 and the fine layer separator 3 are connected through a first aqueous phase conveying pipeline 7.

[0059] The system of this application is also provided with a circulation pump 9. The inlet of the circulation pump 9 is connected to the aqueous phase outlet of the separator 5 through a second aqueous phase conveying pipeline 8, and the outlet of the circulation pump 9 is connected to the hydrolysis reactor 1.

[0060] The second aqueous phase conveying pipeline 8 is also connected to the first aqueous phase conveying pipeline 7.

[0061] The system of this application is also provided with a water supply pipeline 10. The water supply pipeline 10 is connected to the second aqueous phase conveying pipeline 8 through a regulating valve 11.

[0062] The hydrolysis reactor 1 is used for hydrolyzing dimethyldichlorosilane. The rough layer separator 2 and the fine layer separator 3 are used for separating oil and water from the dimethyldichlorosilane hydrolysis product.

[0063] The water washing tank 4 is used for washing soluble impurities in the dimethyldichlorosilane hydrolysis product.

[0064] The separator 5 is used for separating the mixture after being washed by the water washing tank 4.

[0065] The gas phase balance pipe 6 is used to keep the liquid level pressure in the rough layer separator 2 and the fine layer separator 3 stable.

[0066] The circulation pump 9 is used to transport the aqueous phase separated from the rough layer separator 2, the fine layer separator 3, and the separator 5 and the liquid in the water supply pipeline 10 to the hydrolysis reactor 1.

[0067] Specifically, dimethyldichlorosilane is hydrolyzed with concentrated hydrochloric acid in the hydrolysis reactor 1 to generate hydrolysis products and hydrogen chloride gas. The hydrolysis products are a mixture of linear and cyclic oligomeric siloxanes. The hydrogen chloride gas is treated and transported to the chloromethane synthesis workshop for reuse as a raw material in silicone production. The generated dimethyldichlorosilane hydrolysis products and dilute hydrochloric acid are transported to the rough separator 2 for the first oil-water separation. According to the different specific gravities of the dimethyldichlorosilane hydrolysis products and dilute hydrochloric acid, automatic separation is carried out. The oil-phase hydrolysis products are on the upper layer, and the water-phase dilute hydrochloric acid is on the lower layer. The hydrolysis products in the rough separator 2 flow by overflow to the fine separator 3. The upper oil-phase hydrolysis products in the rough separator 2 contain a small amount of chloride ions and other impurities. After standing for the second oil-water separation in the fine separator 3, the upper hydrolysis products overflow into the water washing tank 4 and are stirred and mixed with water. The chloride ions and other impurities in the hydrolysis products dissolve in water, greatly reducing the chloride ion content in the hydrolysis products, thereby reducing the viscosity of the hydrolysis products and improving the quality of the hydrolysis products. The mixture after washing in the water washing tank 4 is transported to the separator 5, and three oil-water separations are carried out through the separator 5 to achieve the separation of the dimethyldichlorosilane hydrolysis products, obtaining relatively pure hydrolysis products for the next cracking process.

[0068] Among them, the tops of the rough separator 2 and the fine separator 3 are connected by a gas-phase balance pipe 6 to maintain the liquid level pressure balance between the rough separator 2 and the fine separator 3, avoiding the water phase in the rough separator 2 flowing into the fine separator 3 due to the too high liquid level pressure in the rough separator 2. The setting of the gas-phase balance pipe 6 improves the oil-water separation efficiency. The bottoms of the rough separator 2 and the fine separator 3 are connected by a first water-phase delivery pipeline 7 to keep the liquid level heights of the rough separator 2 and the fine separator 3 the same. At the same time, the second water-phase delivery pipeline 8 is also connected to the first water-phase delivery pipeline 7. The inlet of the circulation pump 9 is connected to the water-phase outlet of the separator 5 through the second water-phase delivery pipeline 8, and the outlet of the circulation pump 9 is connected to the hydrolysis reactor 1. Through the circulation pump 9, the water-phase dilute hydrochloric acid in the rough separator 2, the fine separator 3 and the separator 5 is transported to the hydrolysis reactor 1 as a supplementary water source to participate in the hydrolysis reaction again, saving water resource utilization and greatly reducing the discharge of waste acid, having good economic and environmental benefits.

[0069] The system of the present application is also provided with a make-up water pipeline 10. A first liquid level transmitter 21 is arranged inside the rough separator 2, and a second liquid level transmitter 31 is arranged inside the fine separator 3. By controlling the liquid flow rate in the make-up water pipeline 10, the oil-water interface of the rough separator 2 and the fine separator 3 is maintained within a reasonable range of the liquid level range. If the oil-water interface of the rough separator 2 and the fine separator 3 drops or rises outside the reasonable range of the liquid level range, resulting in an excessive amount of oil layer or water layer in the rough separator 2 and the fine separator 3, it takes a long time to balance the oil-water interface. Since the hydrolysis product contains chloride ions, the longer the balancing time, the higher the chloride ion content in the hydrolysis product will cause the viscosity of the hydrolysis product to increase, directly affecting the production of subsequent products, and at the same time will block the equipment, increasing the production cost. In the present application, the water phases of the rough separator 2 and the fine separator 3 are transported to the hydrolysis reactor 1 through the first water phase transportation pipeline 7 and the second water phase transportation pipeline 8 to continue to participate in the reaction. When the oil-water interface of the rough separator 2 and the fine separator 3 drops, it is necessary to make up water into the hydrolysis reactor 1 to ensure the stability of the oil-water interface of the rough separator 2 and the fine separator 3. The make-up water pipeline 10 is connected to the second water phase transportation pipeline 8 through a regulating valve 11. When the oil-water interface of the fine separator 3 drops, the regulating valve 11 is controlled to adjust the flow rate of the make-up water pipeline 10, and the make-up water volume entering the hydrolysis reactor 1 is controlled, so as to maintain the balance of the oil-water interface of the rough separator 2 and the fine separator 3. By setting the fine separator, the oil-water interface is separated more thoroughly and the interface control is more accurate, which is more conducive to controlling the regulating valve 11 to control the make-up water volume. The liquid in the make-up water pipeline 10 is hydrochloric acid or water.

[0070] In this embodiment, through the above system, by setting a rough separator and a fine separator, the hydrolysis product is subjected to multiple oil-water separations to reduce the chloride ion content in the hydrolysis product. The hydrolysis product is further washed for chloride ions by setting a water washing tank, greatly reducing the chloride ion content in the hydrolysis product, thereby reducing the viscosity of the hydrolysis product and improving the quality of the hydrolysis product. By transporting the dilute hydrochloric acid in the water phases of the rough separator, the fine separator and the separator to the hydrolysis reactor as a supplementary water source, resources are saved, and at the same time, the discharge of waste acid is greatly reduced, having good economic and environmental benefits. At the same time, the setting of the fine separator makes the oil-water interface separation more thorough and the interface control more accurate, which is more conducive to controlling the regulating valve 11 to control the make-up water volume of the hydrolysis reactor, thereby maintaining the balance of the oil-water interface of the rough separator and the fine separator, reducing the viscosity of the hydrolysis product, and ensuring the quality of the hydrolysis product.

[0071] Figure 2 It is a schematic structural diagram of the interface control device of the dimethyldichlorosilane hydrolysis product separation system provided by an embodiment of the present application, as Figure 2As shown, optionally, the system of the present application is further provided with an interface control device 12. The interface control device includes a second liquid level transmitter 31, a regulator 121, and a regulating valve 11. The regulator 121 is connected between the second liquid level transmitter 31 and the regulating valve 11.

[0072] Specifically, the interface control device 12 is used to control the balance of the oil-water interface of the rough separator 2 and the fine separator 3. When the oil-water interface of the rough separator 2 and the fine separator 3 drops, the second liquid level transmitter 31 transmits the liquid level signal to the regulator 121. The regulator 121 determines the deviation between the existing actual liquid level value and the given process parameter value, and transmits a correction signal to the regulating valve 11. The regulating valve 11 controls the flow rate of the makeup water pipeline 10, so that the oil-water interface of the rough separator 2 and the fine separator 3 reaches the given process parameter value, thereby maintaining the balance of the oil-water interface of the rough separator 2 and the fine separator 3, enabling the hydrolysis product and dilute hydrochloric acid in the rough separator 2 and the fine separator 3 to quickly separate, and reducing the influence of chloride ions in the hydrolysis product on the viscosity of the hydrolysis product.

[0073] Among them, the regulating valve 11 can also be controlled by connecting the first liquid level transmitter 21 in the rough separator 2 with the regulator 121, and then the oil-water interface of the rough separator 2 and the fine separator 3 is balanced. However, the oil-water interface of the fine separator 3 is separated more clearly than that of the rough separator 2. Therefore, controlling the regulating valve 11 with the oil-water interface of the fine separator 3 is more accurate, which is more conducive to the separation of the hydrolysis product.

[0074] Optionally, the oil-water interface of the rough separator 2 and the fine separator 3 is controlled at 20%-80% of the liquid level range.

[0075] Specifically, controlling the oil-water interface of the rough separator 2 and the fine separator 3 at 20%-80% of the liquid level range. If the oil-water interface of the rough separator 2 and the fine separator 3 drops or rises outside the reasonable range of the liquid level range, it will cause too much oil layer or water layer in the rough separator 2 and the fine separator 3. Then, it takes a long time to balance the oil-water interface. Since the hydrolysis product contains chloride ions, the longer the balance time, the higher the chloride ions in the hydrolysis product will cause the viscosity of the hydrolysis product to increase, directly affecting the production of subsequent products. At the same time, it will block the equipment and increase the production cost. Preferably, the oil-water interface of the rough separator 2 and the fine separator 3 is controlled at 50%-60% of the liquid level range.

[0076] Figure 3 It is a schematic structural diagram of the water washing tank of the dimethyldichlorosilane hydrolysis product separation system provided by another embodiment of the present application. As Figure 3 shown, optionally, a stirring device is arranged in the water washing tank 4. The stirring device includes a motor 41, a stirring shaft 42, and a plurality of stirring components. The motor 41 is rotationally connected to one end of the stirring shaft 42, and the plurality of stirring components are equidistantly installed along the height direction of the stirring shaft 42.

[0077] Specifically, a stirring device is provided inside the water washing tank 4 for fully stirring and mixing the hydrolysis product and water. The motor 41 is rotatably connected to one end of the stirring shaft 42. The motor 41 serves as a power source to provide electrical energy for the rotation of the stirring shaft 42. The rotation of the stirring shaft 42 drives the rotation of a plurality of stirring components, thereby causing the plurality of stirring components to drive the movement of the hydrolysis product and water. The setting of a plurality of stirring components makes the mixing of the hydrolysis product and water more sufficient, thereby dissolving chloride ions and other impurities in the hydrolysis product in water, greatly reducing the chloride ion content in the hydrolysis product, reducing the viscosity of the hydrolysis product, and at the same time reducing the corrosion of the equipment by chloride ions. Washing the chloride ions and other impurities in the hydrolysis product with water can recycle dilute hydrochloric acid for the hydrolysis reaction compared with using lye, realizing the collection of hydrochloric acid, making good use of by-product hydrochloric acid, reducing production costs, and increasing profits.

[0078] As Figure 3 shown, optionally, a mounting frame 45 is fixedly provided at the top of the water washing tank 4, and the motor 41 is arranged on the top of the mounting frame 45. The stirring shaft 42 passes through the mounting frame 45 and is rotatably connected to the motor 41.

[0079] Specifically, the mounting frame 45 is fixedly provided at the top of the water washing tank 4, and the motor 41 is arranged on the top of the mounting frame 45. As the stirring device operates, the stirring shaft 42 rotates continuously. The mounting frame 45 makes the operation of the motor 41 and the stirring shaft 42 more stable. If the motor 41 is directly arranged on the top of the water washing tank 4, the continuous rotation of the stirring shaft 42 causes frictional damage to the water washing tank 4, which is not conducive to the long-term operation of the equipment. Such a setting makes the system operate more stably.

[0080] As Figure 3 shown, optionally, the stirring component includes three stirring arms 43. One ends of the three stirring arms 43 are fixedly arranged at the same position of the stirring shaft 42, and stirring blades 44 are welded to the other ends of the three stirring arms 43.

[0081] Specifically, stirring blades 44 are welded to the other ends of the stirring arms 43. The stirring blades 44 can increase the resistance to the movement of the hydrolysis product and water, make the mixing of the hydrolysis product and water more uniform, improve the efficiency of dissolving chloride ions and other impurities in water, and reduce the chloride ion content in the hydrolysis product.

[0082] Optionally, among the three stirring arms 43 of the stirring component, the included angle between adjacent stirring arms 43 is 120°.

[0083] Specifically, the included angle between adjacent stirring arms 43 is 120°, which not only improves the stirring efficiency but also makes the forces on the three stirring arms 43 uniform during stirring, facilitating the long-term operation of the system.

[0084] Optionally, at least one stirring arm 43 in the stirring assembly is inclined upward or downward relative to the horizontal plane, and the inclination directions of adjacent stirring arms 43 are opposite.

[0085] Specifically, the stirring arm 43 is inclined upward and downward relative to the horizontal plane. Compared with setting the stirring arm 43 in only one direction, it can achieve the horizontal and vertical stirring of the mixture of hydrolysis product and water, making the stirring more uniform, ensuring that there is no dead angle in the stirring, being beneficial to the mixing of the hydrolysis product and water, being beneficial to the washing of chloride ions and other impurities in the hydrolysis product, and improving the separation efficiency of the hydrolysis product.

[0086] Optionally, a baffle plate 46 is further arranged in the water washing tank 4, and a plurality of baffle plates 46 are fixedly arranged along the inner wall of the water washing tank 4.

[0087] Specifically, a plurality of baffle plates 46 are fixedly arranged along the inner wall of the water washing tank 4, so that during the movement of the hydrolysis product and water along with the stirring blade 44, they collide with the surface of the baffle plate 46, increasing the contact time between the hydrolysis product and water, dissolving chloride ions and other impurities in the hydrolysis product in water, and further improving the separation efficiency of the hydrolysis product.

[0088] Optionally, the cross-sectional shape of the baffle plate 46 is one of a quadrilateral, a triangle, and at least one side being arc-shaped.

[0089] Specifically, the cross-sectional shape of the baffle plate 46 is one of a quadrilateral, a triangle, and at least one side being arc-shaped. By making the moving hydrolysis product and water collide with the baffle plate 46, the contact time between the hydrolysis product and water can be increased, and the washing efficiency of chloride ions and other impurities in the hydrolysis product can be improved.

[0090] The technical solution of the present application will be described in detail below with specific embodiments.

[0091] In this embodiment, the operation process of the dimethyldichlorosilane hydrolysis product separation system during specific operation is as follows:

[0092] (1) Primary oil-water separation: After dimethyldichlorosilane undergoes a hydrolysis reaction with concentrated hydrochloric acid in the hydrolysis reactor 1, a linear and cyclic oligomeric siloxane mixture and hydrogen chloride gas are generated. The hydrogen chloride gas is processed and transported to the chloromethane synthesis workshop for reuse as a raw material for silicone production. The generated dimethyldichlorosilane hydrolysis product and dilute hydrochloric acid are transported to the rough separator 2 for primary oil-water separation. The oil-phase hydrolysis product is on the upper layer, and the water-phase dilute hydrochloric acid is on the lower layer.

[0093] (2) Secondary oil-water separation: The upper-layer hydrolysis product in the rough separator 2 overflows and flows by gravity to the fine separator 3. The upper-layer hydrolysis product in the rough separator 2 contains a small amount of chloride ions and other impurities, and secondary oil-water separation is carried out by standing in the fine separator 3.

[0094] (3) Water washing: The upper-layer hydrolysis product obtained from the secondary oil-water separation overflows into the water washing tank 4 and is stirred and mixed with water to wash the chlorine-containing impurities in the hydrolysis product. Among them, the included angle between adjacent stirring arms 43 in the stirring device is 120°. At least one stirring arm 43 in the stirring assembly is inclined upward or downward relative to the horizontal plane, and the inclination directions of adjacent stirring arms are opposite. A baffle plate is also arranged in the water washing tank, and the cross-sectional shape of the baffle plate is one of a quadrilateral, a triangle, and at least one side being arc-shaped.

[0095] (4) Tertiary oil-water separation: The hydrolysis product and water in the water washing tank 4 are subjected to tertiary oil-water separation through the separator 5, realizing the separation of the hydrolysis product of dimethyldichlorosilane and obtaining a relatively pure hydrolysis product for the next cracking process.

[0096] (5) Aqueous phase circulation and oil-water interface control: The tops of the rough separator 2 and the fine separator 3 are connected through the gas-phase balance pipe 6 to maintain the liquid level pressure balance between the rough separator 2 and the fine separator 3. The second aqueous phase delivery pipeline 8 is connected to the first aqueous phase delivery pipeline 7, and through the circulation pump 9, the dilute hydrochloric acid in the aqueous phase in the rough separator 2, the fine separator 3, and the separator 5 is transported to the hydrolysis reactor 1 as a supplementary water source. By controlling the flow rate of the makeup water pipeline 10, the oil-water interface between the rough separator 2 and the fine separator 3 is maintained within a reasonable range. When the oil-water interface between the rough separator 2 and the fine separator 3 drops, the second liquid level transmitter 31 transmits the liquid level signal to the regulator 121. The regulator 121 determines the deviation between the existing actual liquid level value and the given process parameter value, and transmits a correction signal to the control valve 11. The control valve 11 controls the flow rate of the makeup water pipeline 10, so that the oil-water interface between the rough separator 2 and the fine separator 3 reaches the given process parameter value, thereby maintaining the balance of the oil-water interface between the rough separator 2 and the fine separator 3. The oil-water interface between the rough separator 2 and the fine separator 3 is controlled within 20%-80% of the liquid level range. Preferably, the oil-water interface between the rough separator 2 and the fine separator 3 is controlled within 50%-60% of the liquid level range.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A separation system for the hydrolysis products of dimethyldichlorosilane, characterized in that, Including: A hydrolysis reactor (1), a rough layer separator (2), a fine layer separator (3), a water washing tank (4) and a separator (5) connected in sequence, and an interface control device (12) is further provided in the system; The tops of the rough layer separator (2) and the fine layer separator (3) are connected through a gas phase balance pipe (6), and the bottoms of the rough layer separator (2) and the fine layer separator (3) are connected through a first aqueous phase conveying pipeline (7); The system is further provided with a circulation pump (9), the inlet of the circulation pump (9) is connected to the aqueous phase outlet of the separator (5) through a second aqueous phase conveying pipeline (8), and the outlet of the circulation pump (9) is connected to the hydrolysis reactor (1); the second aqueous phase conveying pipeline (8) is also connected to the first aqueous phase conveying pipeline (7); The interface control device (12) includes a second liquid level transmitter (31), a regulator (121) and a regulating valve (11); A first liquid level transmitter (21) is arranged inside the rough layer separator (2), a second liquid level transmitter (31) is arranged inside the fine layer separator (3), and a water supply pipeline (10) is further provided in the system. The water supply pipeline (10) is connected to the second aqueous phase conveying pipeline (8) through a regulating valve (11); the regulator (121) is connected between the second liquid level transmitter (31) and the regulating valve (11); The oil-water interfaces of the rough layer separator (2) and the fine layer separator (3) are controlled at 20%-80% of the liquid level range.

2. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 1, characterized in that, A stirring device is arranged inside the water washing tank (4). The stirring device includes a motor (41), a stirring shaft (42) and a plurality of stirring components. The motor (41) is rotationally connected to one end of the stirring shaft (42), and the plurality of stirring components are equidistantly installed along the height direction of the stirring shaft (42).

3. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 2, characterized in that, An installation frame (45) is fixedly arranged at the top of the water washing tank (4). The motor (41) is arranged on the top of the installation frame (45), and the stirring shaft (42) passes through the installation frame (45) and is rotationally connected to the motor (41).

4. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 3, characterized in that, The stirring component includes three stirring arms (43). One ends of the three stirring arms (43) are fixedly arranged at the same position of the stirring shaft (42), and stirring blades (44) are welded to the other ends of the three stirring arms (43).

5. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 4, characterized in that, Among the three stirring arms (43) of the stirring component, the included angle between adjacent stirring arms (43) is 120°.

6. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 4, characterized in that, At least one of the stirring arms (43) in the stirring component is inclined upward or downward relative to the horizontal plane, and the inclination directions of adjacent stirring arms (43) are opposite.

7. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 1, characterized in that, A baffle plate (46) is further arranged inside the water washing tank (4), and a plurality of baffle plates (46) are fixedly arranged along the inner wall of the water washing tank (4).

8. The separation system for the hydrolysis products of dimethyldichlorosilane according to claim 7, characterized in that, The cross-sectional shape of the baffle plate (46) is one of a quadrilateral, a triangle and at least one side being arc-shaped.

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