Dechlorination method of chlorosilane hydrolysate

Abstract

The invention relates to a chlorine removal method for chlorosilane hydrolysate, which comprises the following steps: carrying out single-stage washing or multi-stage countercurrent washing on the chlorosilane hydrolysate, and each stage of washing in the single-stage washing or the multi-stage countercurrent washing comprises the following steps: S100, feeding the chlorosilane hydrolysate and a washing agent into a static mixer for mixing; s200, feeding the mixture into a first coalescer for treatment; s300, feeding a product of the first coalescer into a second coalescer for treatment; s400, conveying a product of the second coalescer into a coalescence buffer tank for separation; wherein in the last-stage washing of the single-stage washing or the multi-stage countercurrent washing, desalted water is used as a washing agent; and besides the first-stage washing, the acid water in the coalescence acid tank of each stage of washing in the multi-stage countercurrent washing is used as a washing agent of the previous stage of washing, and the acid water in the coalescence acid tank of the first-stage washing in the single-stage washing and the multi-stage countercurrent washing is returned to the hydrolysis unit.

Description

Technical Field

[0001] The invention belongs to the technical field of organic silicon, and particularly relates to a method for removing chlorine from chlorosilane hydrolyzate. Background Art

[0002] Chlorosilanes (e.g., methylchlorosilane, especially dimethyldichlorosilane) are important monomers in the silicone industry and are also the most basic monomers for preparing silicone oil, silicone rubber, and silicone resin. However, chlorosilanes such as dimethyldichlorosilane are often not used directly in industry, but their hydrolyzates are used to prepare various polysiloxane products.

[0003] At present, the hydrolysis products of chlorosilane are usually treated by water washing process. The chloride ion content in the obtained hydrolysis products after water washing is usually 25-200ppm, which is too high. In addition, due to the poor separation effect of the water washing process, a large amount of water is required for washing, which produces a large amount of acid water with high COD. In addition, the hydrolysis products will corrode downstream pipelines and equipment, and cannot be directly sent to the refining system for the production of high-quality products. Therefore, how to effectively reduce the chloride ion content in the hydrolysis products will become a key research direction.

[0004] For example, Chinese patent application CN202210230895.2 discloses a method for dechlorinating a dimethyldichlorosilane hydrolyzate, comprising: (1) a multi-stage countercurrent washing process: transferring a dimethyldichlorosilane crude hydrolyzate and water into a multi-stage countercurrent washing device, removing part of the hydrogen chloride in the dimethyldichlorosilane crude hydrolyzate through multi-stage countercurrent washing, and obtaining a washed hydrolyzate; (2) a dechlorination process: transferring the washed hydrolyzate obtained after multi-stage countercurrent washing into a dechlorination treatment device, adjusting the temperature of the dechlorination treatment device to 50-60°C and the air pressure to -0.08MPa--0.06MPa, so that the washed hydrolyzate is again dechlorinated and dehydrated in the dechlorination treatment device, and obtaining a dechlorinated dimethyldichlorosilane hydrolyzate. Thus, the dechlorination method achieves the purpose of removing chlorine from the hydrolyzate without alkali washing, avoids the problem of new impurities introduced by alkali washing, and improves the quality of the hydrolyzate. However, this dechlorination method has the following main disadvantages: (1) The effect of multi-stage countercurrent water washing is poor and cannot achieve the effect of efficient dechlorination; (2) Although alkaline washing is not required, a dechlorination system is added, new equipment is introduced, energy consumption is increased, and investment is also increased. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for dechlorinating chlorosilane hydrolyzate in order to solve the technical problems existing in the prior art. The method for dechlorinating chlorosilane hydrolyzate of the present invention reduces the content of chloride ions in the hydrolyzate after water washing, improves the product quality of the hydrolyzate, and reduces the COD content and discharge amount of acid water discharged into sewage.

[0006] The objectives of the present invention are achieved through the following technical solutions.

[0007] The present invention provides a method for dechlorinating chlorosilane hydrolysate, wherein the method for dechlorinating chlorosilane hydrolysate comprises performing single-stage water washing or multi-stage countercurrent water washing on the chlorosilane hydrolysate, wherein each stage of water washing in the single-stage water washing or the multi-stage countercurrent water washing comprises:

[0008] S100, sending the chlorosilane hydrolyzate and the water washing agent into a static mixer for mixing to obtain a mixture; wherein the outlet temperature of the static mixer is 45-70° C., and the outlet pressure is 0.1-0.5 MPa;

[0009] S200, the mixture is sent to a first coalescer for treatment to obtain first acid water and a first coalescer product, and the first acid water is sent to a coalescing acid tank;

[0010] S300, the product of the first coalescer is sent to a second coalescer for treatment to obtain second acid water and a second coalescer product, and the second acid water is sent to a coalescing acid tank;

[0011] S400, the product of the second coalescer is sent to a coalescing buffer tank for separation to obtain a third acid water and a hydrolyzed product after washing, and the third acid water is sent to a coalescing acid tank;

[0012] In which, in the last stage of single-stage water washing or multi-stage countercurrent water washing, desalted water is used as the washing agent; and except for the first stage water washing, the acid water in the agglomerated acid tank of each stage of water washing in the multi-stage countercurrent water washing is used as the washing agent for the previous stage water washing, and the acid water in the agglomerated acid tank of the first stage of water washing in the single-stage water washing and multi-stage countercurrent water washing is returned to the hydrolysis unit.

[0013] In the present invention, desalted water (DMW) is used to perform single-stage water washing or multi-stage countercurrent water washing on the chlorosilane hydrolyzate. In the specific water washing step, the chlorosilane hydrolyzate and the water washing agent are fully mixed in a static mixer. After the mixture passes through the first coalescer, a part of acid water can be separated. The obtained first coalescer product passes through the second coalescer, and is further coalesced and separated. The obtained second coalescer product is separated in a coalescing material buffer tank to obtain a washed hydrolyzate with low chloride ion content. The acid water produced in the first coalescer, the second coalescer and the coalescing buffer tank is collected in a coalescing acid tank, and the acid water can be returned to the previous water washing or returned to the hydrolysis unit. The DMW flow rate is preferably 3000-5500kg / h, more preferably 3500-5000kg / h.

[0014] According to the method for removing chlorine from chlorosilane hydrolyzate provided by the present invention, the chlorosilane hydrolyzate includes hydrolysis products of monomers such as dimethyldichlorosilane, monomethyltrichlorosilane, monomethylhydrochlorosilane, trimethylchlorosilane, phenyldichlorosilane, phenylhydrochlorosilane, and phenyltrichlorosilane.

[0015] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, the multi-stage countercurrent water washing includes 2 to 5 stages of countercurrent water washing, for example, 2 stages of countercurrent water washing, 3 stages of countercurrent water washing, 4 stages of countercurrent water washing or 5 stages of countercurrent water washing.

[0016] According to the chlorosilane hydrolyzate dechlorination method provided by the present invention, wherein, the pressure drop of the static mixer described in step S100 is 100~200KPa, specifically, can be 100KPa, 110KPa, 120KPa, 130KPa, 140KPa, 150KPa, 160KPa, 180KPa, 200KPa or the range of its composition, preferably 120~150KPa, most preferably 140~150KPa. The inventor of the present application found that under the same conditions, increasing the pressure difference (pressure drop) of the static mixer can reduce the chloride ion content in the obtained washed hydrolyzate. However, when the pressure drop of the static mixer is too large, the transparency of the coalesced acid water obtained is reduced instead, and oil flowers appear after placement.

[0017] In some preferred embodiments, the pressure drop of the static mixer in step S100 is 120-150 KPa.

[0018] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, wherein the outlet temperature of the static mixer in step S100 is 45-60° C., more preferably 45-55° C.; and / or the outlet pressure is 0.2-0.4 MPa, preferably 0.2-0.3 MPa.

[0019] According to the method for removing chlorine from chlorosilane hydrolyzate provided by the present invention, the mass ratio of the chlorosilane hydrolyzate to the water washing agent in step S100 is 2 to 6: 1. For example, the mass ratio of the chlorosilane hydrolyzate to the water washing agent in step S100 is 2: 1, 2.5: 1, 3: 1, 3.5: 1, 4: 1, 4.25: 1, 4.5: 1, 5: 1, 5.5: 1 or a range thereof.

[0020] In some embodiments, the mass ratio of the chlorosilane hydrolyzate to the water wash in step S100 is 2.5 to 4.5: 1, preferably 3 to 4.25: 1. In such a range, the method of the present invention has a high dechlorination effect and has little effect on the viscosity of the hydrolyzate.

[0021] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, the step S200 further comprises: before the mixture is fed into the first coalescer, feeding the mixture into a pre-filter for treatment.

[0022] In the present invention, the filter element of the pre-filter is preferably a polypropylene filter element. Such a polypropylene filter element has a high flow rate, can quickly process the mixture, and can effectively remove impurities such as particulate matter and gel.

[0023] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, the coalescing filter elements in the first coalescer and the second coalescer are independently selected from high-efficiency coalescing filter elements. In the present invention, the material of the coalescing filter element is resistant to hydrochloric acid corrosion. Examples of high-efficiency coalescing filter elements suitable for use in the present invention include, but are not limited to, polypropylene coalescing filter elements, polyurethane coalescing filter elements, glass fiber coalescing filter elements, and fluorine-containing fiber coalescing filter elements.

[0024] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, the liquid levels of the first coalescer, the second coalescer and the coalescing buffer tank are independently controlled at 40% to 60%, for example, 50%.

[0025] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, the treatment conditions in steps S200 and S300 independently include: a temperature of 45 to 70° C., preferably 45 to 60° C., and more preferably 45 to 55° C.

[0026] According to the method for dechlorination of chlorosilane hydrolyzate provided by the present invention, after single-stage water washing or multi-stage countercurrent water washing treatment, the chloride ion content of the chlorosilane hydrolyzate is less than 10 ppm, preferably less than 8 ppm, less than 6 ppm, less than 5 ppm, less than 3 ppm, or less than 1 ppm.

[0027] The chlorosilane hydrolyzate dechlorination method of the present invention has the following advantages:

[0028] (1) The method for removing chlorine from chlorosilane hydrolyzate of the present invention adopts single-stage or multi-stage countercurrent water washing, and the chlorine removal efficiency of the hydrolyzate can reach more than 99%, and the chloride ion content can be reduced to less than 10 ppm, especially less than 1 ppm. The chlorine removal efficiency is high, and the quality of the product hydrolyzate can be improved;

[0029] (2) The method for dechlorinating chlorosilane hydrolyzate of the present invention requires less water, and the separated acid water is transparent, clean, and free of oil spots, thereby reducing the amount of acid water generated by hydrolysis and the COD content of the acid water;

[0030] (3) The product obtained by the dechlorination method of chlorosilane hydrolyzate of the present invention can be used to prepare α, ω-dihydroxy polydimethylsiloxane (107 silicone rubber), or to prepare dimethylcyclosiloxane mixture (DMC) by cracking, and further to prepare silicone oil, silicone rubber, silicone resin and other products, which has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a schematic diagram of a flow chart according to an embodiment of the present invention; wherein, 1. static mixer; 2. prefilter; 3. first coalescer; 4. second coalescer; 5. coalescing buffer tank; 6. coalescing acid tank; 7. chlorosilane hydrolyzate; 8. acid water; 9. hydrolyzate after washing;

[0032] Figure 2 It is a flow diagram of the comparative example of the present application; wherein, 1', a primary static mixer; 2', a primary pre-filter; 3', a primary coalescer; 4', a secondary coalescer; 5', a buffer tank; 6', a secondary coalescing acid tank; 7', a chlorosilane hydrolyzate; 8', acid water; 9', a hydrolyzate after washing; 10', a secondary static mixer; 11', a primary coalescing acid tank. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The instrument used in the present invention is as follows:

[0035] Static mixer, SM-H type, specification SH-36 / 150, DN is 150mm, Dh is 36mm, flow rate is 31~63m3 / h;

[0036] Pre-filter, model 3XD-40, PP pleated filter element, working pressure 0~1MPa;

[0037] Coalescer, JJB type liquid-liquid coalescing separator, brand LYC-400J, glass fiber filter element, filter accuracy 10 microns.

[0038] The raw materials and instruments not particularly limited in the present invention can all be commercially available.

[0039] Example 1

[0040] Reference Figure 1 The method for dechlorination of chlorosilane hydrolyzate is as follows.

[0041] (1) The hydrolyzate of dimethyldichlorosilane (flow rate of 15000 kg / h, chloride ion content of 303 ppm, viscosity of 25.2 cp at 20° C.) and desalted water DMW (3500 kg / h) are fed into a static mixer 1 for mixing to obtain a mixture; wherein the outlet temperature of the static mixer 1 is 50° C., the outlet pressure is 0.3 MPa, and the pressure difference is 100 KPa.

[0042] (2) The mixture is sent to the pre-filter 2 for treatment to filter out impurities such as particulate matter and gel, and then sent to the first agglomerator 3 for treatment to obtain first acid water and a first agglomerator product. The first acid water is sent to the agglomerated acid tank 6; wherein the interface of the first agglomerator 3 is controlled to be 50%.

[0043] (3) The product of the first coalescer is sent to the second coalescer 4 for treatment to obtain second acid water and a second coalescer product, and the second acid water is sent to the coalescing acid tank 6; wherein the interface of the second coalescer 4 is controlled to be 50%.

[0044] (4) The product of the second coalescer is sent to the coalescing buffer tank 5 for separation to obtain third acid water and a hydrolyzed product 9 after washing. The third acid water is sent to the coalescing acid tank 6. The liquid level of the coalescing acid tank is controlled to be 50%.

[0045] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 1 was tested, and the viscosity of the washed hydrolyzate was 25.4 cp and the chloride ion content was 10 ppm.

[0046] Example 2

[0047] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 1, except that: (1) the chloride ion content in the dimethyldichlorosilane hydrolyzate was 303 ppm, and the viscosity at 20°C was 25.2 cp; and (2) the outlet temperature of the static mixer 1 was 50°C, the outlet pressure was 0.28 MPa, and the pressure difference was 120 KPa.

[0048] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 2 was tested, and the viscosity of the washed hydrolyzate was 25.4 cp and the chloride ion content was 5 ppm.

[0049] Example 3

[0050] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 1, except that: (1) the chloride ion content of the dimethyldichlorosilane hydrolyzate was 312 ppm, and the viscosity at 20°C was 25.4 cp; and (2) the outlet temperature of the static mixer 1 was 50°C, the outlet pressure was 0.27 MPa, and the pressure difference was 130 KPa.

[0051] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 3 was tested, and the washed hydrolyzate had a viscosity of 25.5 cp and a chloride ion content of 3 ppm.

[0052] Example 4

[0053] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 1, except that: (1) the chloride ion content in the dimethyldichlorosilane hydrolyzate was 316 ppm, and the viscosity at 20°C was 25.7 cp; and (2) the outlet temperature of the static mixer 1 was 50°C, the outlet pressure was 0.26 MPa, and the pressure difference was 140 KPa.

[0054] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 4 was tested, and the washed hydrolyzate had a viscosity of 25.7 cp and a chloride ion content of 1 ppm.

[0055] Example 5

[0056] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 1, except that: (1) the chloride ion content in the dimethyldichlorosilane hydrolyzate was 315 ppm, and the viscosity at 20° C. was 25.6 cp; and (2) the outlet temperature of the static mixer 1 was 50° C., the outlet pressure was 0.25 MPa, and the pressure difference was 150 KPa.

[0057] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 5 was tested, and the viscosity of the washed hydrolyzate was 25.6 cp and the chloride ion content was 0.3 ppm.

[0058] Example 6

[0059] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 1, except that: (1) the chloride ion content in the dimethyldichlorosilane hydrolyzate was 311 ppm, and the viscosity at 20°C was 25.5 cp; and (2) the outlet temperature of the static mixer 1 was 50°C, the outlet pressure was 0.22 MPa, and the pressure difference was 180 KPa.

[0060] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 6 was tested, and the viscosity of the washed hydrolyzate was 25.7 cp and the chloride ion content was 3 ppm.

[0061] Table 1 Treatment results of Examples 1 to 6

[0062]

[0063] As can be seen from Table 1, under other identical conditions, when the pressure difference (pressure drop) of the static mixer increases from 100 KPa to 150 KPa, the chloride ion content in the obtained washed hydrolysate decreases, and the chlorine removal efficiency can reach 99%. However, when the pressure drop of the static mixer is further increased to 180 KPa, the chloride ion content in the obtained washed hydrolysate no longer decreases, and the transparency of the obtained agglomerated acid water decreases, and oil spots appear after being placed.

[0064] In addition, it can be seen from Table 1 that the method of the present invention has little effect on the viscosity of the hydrolyzate.

[0065] Example 7

[0066] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 2, except that: (1) the chloride ion content of the dimethyldichlorosilane hydrolyzate was 315 ppm, and the viscosity at 20° C. was 25.4 cp; and (2) the amount of desalted water DMW used was 3000 kg / h.

[0067] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 7 was tested, and the viscosity of the washed hydrolyzate was 25.5 cp and the chloride ion content was 8.7 ppm.

[0068] Example 8

[0069] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 2, except that: (1) the chloride ion content of the dimethyldichlorosilane hydrolyzate was 315 ppm, and the viscosity at 20° C. was 25.4 cp; and (2) the amount of desalted water DMW used was 4000 kg / h.

[0070] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 8 was tested, and the viscosity of the washed hydrolyzate was 25.4 cp and the chloride ion content was 4 ppm.

[0071] Example 9

[0072] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 2, except that: (1) the chloride ion content of the dimethyldichlorosilane hydrolyzate was 321 ppm, and the viscosity at 20° C. was 25.7 cp; and (2) the amount of desalted water DMW used was 4500 kg / h.

[0073] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 9 was tested, and the viscosity of the washed hydrolyzate was 25.4 cp and the chloride ion content was 2.1 ppm.

[0074] Example 10

[0075] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 2, except that: (1) the chloride ion content of the dimethyldichlorosilane hydrolyzate was 315 ppm, and the viscosity at 20° C. was 25.6 cp; and (2) the amount of desalted water DMW used was 5000 kg / h.

[0076] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 10 was tested, and the washed hydrolyzate had a viscosity of 25.6 cp and a chloride ion content of 1.2 ppm.

[0077] Embodiment 11

[0078] The chlorosilane hydrolyzate was treated in a method substantially the same as in Example 2, except that: (1) the chloride ion content of the dimethyldichlorosilane hydrolyzate was 315 ppm, and the viscosity at 20° C. was 25.5 cp; and (2) the amount of desalted water DMW used was 5500 kg / h.

[0079] The acid water in the coalescing acid tank 6 is very clear, clean and free of oil. The washed hydrolyzate produced in Example 10 was tested, and the viscosity of the washed hydrolyzate was 25.7 cp and the chloride ion content was 1.0 ppm.

[0080] Table 2 Treatment results of Examples 7 to 11

[0081]

[0082] As can be seen from Table 2, when other conditions are the same, the flow rate of desalted water DMW increases from 3000kg / h to 5000kg / h, the chloride ion content in the obtained washed hydrolyzate decreases, and the dechlorination efficiency can reach 99%. However, when the flow rate of desalted water DMW increases to 5500kg / h, the reduction range of chloride ion content significantly decreases. Similarly, the method of the present invention has little effect on the viscosity of the hydrolyzate.

[0083] Example 12

[0084] 1. First stage countercurrent washing

[0085] (1) The hydrolyzate of dimethyldichlorosilane (flow rate of 15000 kg / h, chloride ion content of 303 ppm, viscosity of 25.2 cp at 20° C.) and the acid water (3500 kg / h) from the second stage countercurrent washing are fed into a static mixer 1 for mixing to obtain a mixture; wherein the outlet temperature of the static mixer 1 is 50° C., the outlet pressure is 0.28 MPa, and the pressure difference is 120 KPa.

[0086] (2) The mixture is sent to the pre-filter 2 for treatment to filter out impurities such as particulate matter and gel, and then sent to the first agglomerator 3 for treatment to obtain first acid water and a first agglomerator product. The first acid water is sent to the agglomerated acid tank 6; wherein the interface of the first agglomerator 3 is controlled to be 50%.

[0087] (3) The product of the first coalescer is sent to the second coalescer 4 for treatment to obtain second acid water and a second coalescer product, and the second acid water is sent to the coalescing acid tank 6; wherein the interface of the second coalescer 4 is controlled to be 50%.

[0088] (4) The product of the second coalescer is sent to the coalescing buffer tank 5 for separation to obtain the third acid water and the hydrolyzed product after the first stage water washing. The third acid water is sent to the coalescing acid tank 6. The liquid level of the coalescing acid tank is controlled to be 50%.

[0089] 2. Second stage countercurrent washing

[0090] The hydrolyzate obtained after the first stage water washing is subjected to a second stage countercurrent water washing in a method substantially the same as the first stage countercurrent water washing, the only difference being that desalted water DMW is used instead of acid water.

[0091] The acid water obtained in the first and second stage countercurrent washing was very clear, clean and free of oil. The hydrolyzed product after washing produced in Example 12 was tested, and the viscosity of the hydrolyzed product after washing was 25.5 cp and the chloride ion content was 0.2 ppm.

[0092] Comparative Example 1

[0093] Reference Figure 2 The method for dechlorination of chlorosilane hydrolyzate is as follows.

[0094] (1) The hydrolyzate 7' of dimethyldichlorosilane (with a flow rate of 15000 kg / h, a chloride ion content of 305 ppm, and a viscosity of 25.3 cp at 20° C.) and the acid water 8' (3500 kg / h) from the secondary coalescing acid tank are fed into a primary static mixer 1' for mixing to obtain a mixture; wherein the outlet temperature of the primary static mixer 1' is 50° C., the outlet pressure is 0.28 MPa, and the pressure difference is 120 KPa.

[0095] (2) The mixture is sent to a primary pre-filter 2' for treatment to filter out impurities such as particulate matter and gel, and then sent to a primary agglomerator 3' for treatment to obtain first acid water and a primary agglomeration product. The first acid water is sent to a primary agglomeration acid tank 11'; wherein the level of the primary agglomerator 3' is controlled to be 50%.

[0096] (3) The primary coalescence product and desalted water DMW (3500 kg / h) are sent to a secondary static mixer 10' for mixing, and then sent to a secondary coalescer 4' for treatment to obtain a second acid water and a secondary coalescence product. The second acid water is sent to a secondary coalescing acid tank 6'; wherein the outlet temperature of the secondary static mixer 10' is 50° C., the outlet pressure is 0.28 MPa, and the pressure difference is 120 KPa; and the interface of the secondary coalescer 4' is controlled to be 50%.

[0097] (4) The secondary coalescence product is sent to a buffer tank 5' for separation to obtain a third acid water and a washed hydrolyzate 9'. The third acid water is sent to a secondary coalescence acid tank 6'. The liquid level of the secondary coalescence acid tank is controlled to be 50%.

[0098] The acid water in the secondary coalescing acid tank and the primary coalescing acid tank was very clear, clean and free of oil. The hydrolyzed product after washing produced in Comparative Example 1 was tested, and the viscosity of the hydrolyzed product after washing was 28.3 cp, and the chloride ion content was 4.8 ppm.

[0099] Table 3 Treatment results of Example 2 and Comparative Example 1

[0100]

[0101] As can be seen from Table 3, the chlorine content in the hydrolyzate prepared by the method of Comparative Example 1 is slightly reduced, but the viscosity of the hydrolyzate changes relatively greatly, and an additional secondary static mixer is required, which is costly.

[0102] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for removing chlorine from chlorosilane hydrolysates, wherein: The method for removing chlorine from chlorosilane hydrolysate comprises performing single-stage water washing or multi-stage countercurrent water washing on the chlorosilane hydrolysate, wherein each stage of water washing in the single-stage water washing or the multi-stage countercurrent water washing comprises: S100, sending the chlorosilane hydrolyzate and the water washing agent into a static mixer for mixing to obtain a mixture; wherein the outlet temperature of the static mixer is 45-70° C., and the outlet pressure is 0.1-0.5 MPa; S200, the mixture is sent to a first coalescer for treatment to obtain first acid water and a first coalescer product, and the first acid water is sent to a coalescing acid tank; S300, the first coalescer product is sent to a second coalescer for treatment to obtain second acid water and a second coalescer product, and the second acid water is sent to a coalescing acid tank; S400, the product of the second coalescer is sent to a coalescing buffer tank for separation to obtain a third acid water and a hydrolyzate after washing, and the third acid water is sent to a coalescing acid tank; In which, in the last stage of single-stage water washing or multi-stage countercurrent water washing, desalted water is used as the washing agent; and except for the first stage water washing, the acid water in the agglomerated acid tank of each stage of water washing in the multi-stage countercurrent water washing is used as the washing agent for the previous stage water washing, and the acid water in the agglomerated acid tank of the first stage of water washing in the single-stage water washing and multi-stage countercurrent water washing is returned to the hydrolysis unit.

2. The method for dechlorination of chlorosilane hydrolyzate according to claim 1, wherein: The chlorosilane hydrolysis products include hydrolysis products of dimethyldichlorosilane, monomethyltrichlorosilane, monomethylhydrochlorosilane, trimethylchlorosilane, phenyldichlorosilane, phenylhydrochlorosilane and phenyltrichlorosilane.

3. The method for dechlorination of chlorosilane hydrolyzate according to claim 1 or 2, wherein: The multi-stage countercurrent water washing includes 2 to 5 stages of countercurrent water washing.

4. The method for dechlorinating chlorosilane hydrolyzate according to any one of claims 1 to 3, wherein: The pressure drop of the static mixer in step S100 is 100-200 KPa, preferably 120-150 KPa.

5. The method for dechlorinating chlorosilane hydrolyzate according to any one of claims 1 to 4, wherein: The outlet temperature of the static mixer in step S100 is 45-60° C., more preferably 45-55° C.; and / or the outlet pressure is 0.2-0.4 MPa, preferably 0.2-0.3 MPa.

6. The method for dechlorination of chlorosilane hydrolyzate according to any one of claims 1 to 5, wherein: The mass ratio of the chlorosilane hydrolyzate to the water wash in step S100 is 2 to 6:1, preferably 2.5 to 4.5:1, and preferably 3 to 4.25:

1.

7. The method for dechlorinating chlorosilane hydrolyzate according to any one of claims 1 to 6, wherein: The step S200 further includes: before the mixture is fed into the first coalescer, feeding the mixture into a pre-filter for treatment.

8. The method for dechlorinating chlorosilane hydrolyzate according to any one of claims 1 to 7, wherein: The liquid levels of the first coalescer, the second coalescer and the coalescing buffer tank are independently controlled at 40% to 60%.

9. The method for dechlorination of chlorosilane hydrolyzate according to any one of claims 1 to 8, wherein: The processing conditions in steps S200 and S300 each independently include: a temperature of 45 to 70°C, preferably 45 to 60°C, and more preferably 45 to 55°C.

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