Device for breaking emulsification of dimethyl dichlorosilane concentrated acid hydrolysis washing loop

Abstract

The utility model discloses a dimethyl dichlorosilane concentrated acid hydrolysis washing loop breaking emulsification device which comprises a first-stage washing kettle, a second loop layering device and a second-stage washing kettle which are sequentially connected, and material inlets of the first-stage washing kettle and the second-stage washing kettle are connected with a desalted water pipeline. A bottom material outlet of the second loop layering device is connected with the first-stage washing kettle, a hydrochloric acid circulating pump is arranged on a connecting pipeline of the two, a material inlet of the first-stage washing kettle is further connected with a second pipeline, an adjusting valve is arranged on the second pipeline, and the adjusting valve is interlocked with a pressure control system. Compared with the prior art, the device disclosed by the utility model has the beneficial effects that dimethyl is added into the first-stage washing kettle, so that the polymerization degree of oligosiloxane is increased, emulsification in the washing process is broken, substances such as various catalysts do not need to be added, and the product quality is not influenced; the device is matched with large system operation, operation such as shutdown discharging is not needed any more, and continuous and safe operation of production is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of concentrated acid hydrolysis of dimethyldichlorosilane, in particular to a device for demulsification of a water washing loop of concentrated acid hydrolysis of dimethyldichlorosilane. Background Art

[0002] At present, the production of silicone at home and abroad generally adopts the concentrated acid hydrolysis loop hydrolysis process, that is, dimethyldichlorosilane (hereinafter referred to as dimethyl) reacts with water to produce concentrated acid and oligosiloxane (hereinafter referred to as hydrolyzate), which are then washed with water and alkaline through a water washing loop, an alkaline washing loop, and a secondary water washing loop, and then stratified to produce qualified hydrolyzate for use in the next process.

[0003] In industrial production, the above method for synthesizing hydrolyzate is mainly to produce hydrogen chloride and preliminary hydrolyzate by reacting diformazan with acid (this is a loop).

[0004] After the hydrolyzate in the first loop is separated from the concentrated acid, it is pressurized by a pump and enters the first-level water washing stage. The first-level water washing is to wash the hydrolyzate with water by adding desalted water. After washing, it is allowed to stand and stratify. The hydrolyzate on the top enters the second-level water washing stage (this is the second loop) through overflow.

[0005] The secondary water washing is again carried out by adding desalted water. After washing, it is allowed to stand for stratification, and the top hydrolyzate overflows into the three-loop hydrolyzate storage tank (this is the three-loop).

[0006] The hydrolyzate from the third loop is pressurized by the third loop hydrolyzate pump and sent to the first-level alkali washing kettle, where it is washed with sodium hydroxide solution and then enters the fourth loop stratifier for static stratification. The upper hydrolyzate enters the second-level alkali washing kettle (this is the fourth loop) through overflow.

[0007] After entering the secondary alkaline washing kettle, the hydrolyzate is washed again with sodium hydroxide solution to remove impurities such as chloride ions entrained in the hydrolyzate. After standing and stratifying, the upper hydrolyzate enters the Fifth Ring Road hydrolyzate storage tank (this is the Fifth Ring Road).

[0008] The material in the five-loop hydrolyzate storage tank is pressurized by the five-loop hydrolyzate pump and then sent to the third-level water washing kettle for the final water washing to completely remove the residual alkali solution and other impurity ions. The final hydrolyzate is placed in the stratifier for stratification and then overflows into the hydrolyzate storage tank (this is the sixth loop).

[0009] The above process is a traditional loop hydrolysis process of dimethylformamide concentrated acid hydrolysis. The process is simple and widely used. However, in the actual production process, the second loop is prone to emulsification, that is, the hydrolyzate and water cannot be completely separated. In severe cases, it may even cause the production to be terminated, which has a great impact on the production and product quality. Therefore, it is urgent to transform and optimize the existing process and completely eliminate the emulsification phenomenon in the production process. Utility Model Content

[0010] In order to solve the above technical problems, the utility model provides a device for demulsifying a dimethyldichlorosilane concentrated acid hydrolysis water washing loop, a dimethyl pipeline is added to the primary water washing kettle, and dimethyl is added to the water washing kettle to achieve the effect of increasing the polymerization degree of oligosilane, demulsifying, and ensuring continuous operation of production.

[0011] To achieve this technical purpose, the utility model adopts the following scheme:

[0012] A device for demulsifying a water washing loop for hydrolyzing dimethyldichlorosilane with concentrated acid comprises a primary water washing kettle, a secondary water washing kettle and a secondary water washing kettle connected in sequence, wherein the material inlets of the primary water washing kettle and the secondary water washing kettle are connected via a desalted water pipeline, the bottom material outlet of the secondary water washing kettle is connected to the primary water washing kettle, a hydrochloric acid circulation pump is arranged on the connecting pipeline between the two, and the device is characterized in that the material inlet of the primary water washing kettle is also connected to a dimethyl pipeline, a regulating valve is arranged on the dimethyl pipeline, and the regulating valve is interlocked with a pressure control system.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] Adding dimethylformamide into the primary water washing kettle increases the degree of polymerization of oligosiloxane and eliminates the emulsification during the water washing process. There is no need to add various catalysts and other substances, and there is no effect on product quality. It matches the operation of the large system and no longer requires operations such as stopping and discharging, ensuring continuous and safe production operation.

[0015] Furthermore, the bottom material outlet of the first-stage water washing kettle is connected to the material inlet of the second-loop stratifier through a pipeline and a "π"-shaped bend.

[0016] Furthermore, a mixer is provided on the material inlet connecting pipelines of the primary water washing kettle and the secondary water washing kettle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a device for demulsifying dimethyldichlorosilane in a concentrated acid hydrolysis water washing loop according to an embodiment of the utility model;

[0018] Marked in the figure: 1. Primary water washing kettle; 2. Secondary loop stratifier; 3. Secondary water washing kettle; 4. Hydrochloric acid circulation pump; 5. Desalted water pipeline; 6. Dimethyl pipeline. DETAILED DESCRIPTION

[0019] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific implementation methods, but the present invention is not limited thereto.

[0020] See also Figure 1The utility model provides a device for demulsifying a water washing loop of dimethyldichlorosilane concentrated acid hydrolysis, comprising a primary water washing kettle 1, a secondary loop stratifier 2, a secondary water washing kettle 3 and a hydrochloric acid circulation pump 4. The bottom material outlet of the primary water washing kettle 1 is connected to the material inlet of the secondary loop stratifier 2 through a pipeline and a "π"-shaped bend, the material outlet pipeline of the secondary loop stratifier 2 is connected to the material inlet of the secondary water washing kettle 3, the bottom material outlet of the secondary loop stratifier 2 is connected to the inlet of the hydrochloric acid circulation pump 4 through a pipeline, the outlet of the hydrochloric acid circulation pump 4 is connected to the material inlet of the primary water washing kettle 1 by a pipeline, the material inlet of the primary water washing kettle 1 is connected to the desalted water pipeline 5 and the dimethyl pipeline 6, the dimethyl pipeline 6 is provided with a regulating valve, and the regulating valve is interlocked with the pressure control system. When the system pressure rises to 0.23MPa, the feed regulating valve of the dimethyl pipeline 6 is automatically closed to cut off the feed, and at the same time, the system pressure relief valve is opened to prevent the system from overpressure and ensure production safety.

[0021] A mixer is provided on the material inlet connecting pipelines of the primary water washing kettle 1 and the secondary water washing kettle 3.

[0022] The working process of the device for demulsification of the water washing loop of dimethyldichlorosilane concentrated acid hydrolysis is as follows: the produced hydrolyzate enters the primary water washing kettle 1 from the previous process, and is washed and mixed with the added desalted water under the stirring action of the primary water washing kettle 1, and the oil-water mixture enters the secondary loop stratifier 2 through overflow. The water phase and the oil phase in the secondary loop stratifier 2 are allowed to stand and stratify under the action of gravity, and the upper oil phase enters the secondary water washing kettle 3 through overflow and is mixed and washed with the added desalted water again. When emulsification occurs during the water washing process, dimethyl is introduced into the primary water washing kettle 1 to increase the polymerization degree of oligosilane, demulsification, and ensure continuous operation of production.

[0023] The amount of dimethylformamide added, the circulation volume of the first-level water washing kettle and the stirring rate are adjusted according to the severity of the emulsification. During the initial emulsification, the amount of dimethylformamide is controlled at 0.2m³ / h, the circulating acid is reduced by 2m³, and the stirring rate is adjusted to 43Hz; during moderate emulsification, the amount of dimethylformamide is controlled at 0.25m³ / h, the circulating acid is reduced by 3.3m³, and the stirring rate is adjusted to 36Hz; in case of severe emulsification, the amount of dimethylformamide is controlled at 0.3m³ / h, the circulating acid is reduced by 4.5m³, and the stirring rate is adjusted to 30Hz or the stirring is stopped; the above adjustments are matched according to the on-site conditions.

[0024] Finally, it should be noted that the above-listed examples are only preferred embodiments of the present invention. Of course, those skilled in the art can make changes and modifications to the present invention. If these modifications and modifications fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the scope of protection of the present invention.

Claims

1. A device for demulsifying a water washing loop for hydrolyzing dimethyldichlorosilane with concentrated acid, comprising a primary water washing kettle (1), a secondary water washing kettle (2) and a secondary water washing kettle (3) connected in sequence, wherein the material inlets of the primary water washing kettle (1) and the secondary water washing kettle (3) are connected by a desalted water pipeline (5), the bottom material outlet of the secondary water washing kettle (2) is connected to the primary water washing kettle (1), and a hydrochloric acid circulation pump (4) is arranged on the connecting pipeline between the two, characterized in that: The material inlet of the primary water washing kettle (1) is also connected to a dimethyl pipe (6), and a regulating valve is provided on the dimethyl pipe (6), and the regulating valve is interlocked with the pressure control system.

2. The device for demulsification of dimethyldichlorosilane concentrated acid hydrolysis water washing loop according to claim 1, characterized in that: The material outlet at the bottom of the primary water washing kettle (1) is connected to the material inlet of the secondary loop stratifier (2) through a pipeline and a "π"-shaped bend.

3. The device for demulsification of dimethyldichlorosilane concentrated acid hydrolysis water washing loop according to claim 1, characterized in that: A mixer is provided on the material inlet connecting pipelines of the first-stage water washing kettle (1) and the second-stage water washing kettle (3).

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