A system and method for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproduct

Abstract

The present invention discloses a system and method for purifying and preparing high-purity silicon tetrachloride from crude silicon tetrachloride byproducts, the system comprises a resin adsorption device, a lightness removal tower, a weight removal tower and a fine removal device, the resin adsorption device is connected with a crude silicon tetrachloride byproduct air inlet pipe, the discharge port of the resin adsorption device is connected with the feed port of the lightness removal tower, the top of the lightness removal tower is connected with a light component removal pipe, the material pipe connected to the bottom of the lightness removal tower is connected with the feed port of the weight removal tower, the bottom of the weight removal tower is connected with a heavy component removal pipe, the material pipe at the top of the weight removal tower is connected with the feed port of the fine removal device, and the discharge port of the fine removal device is connected with a high-purity silicon tetrachloride delivery pipe. The process route of the present invention is simple, no chemical reaction occurs during the production process, and the introduction of new other impurities is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of gas by-product purification, and in particular to a system and method for purifying crude silicon tetrachloride by-product to prepare high-purity silicon tetrachloride. Background Art

[0002] Phenylchlorosilane is a general term for monophenyltrichlorosilane, diphenyldichlorosilane and triphenylmonochlorosilane. It is an important fine chemical material and is widely used in the production and preparation of phenyl silicone oil, silicone resin, silicone rubber, silane coupling agent, coatings, etc.

[0003] Currently, the main synthesis methods of phenylchlorosilane include direct method, condensation method and Grignard reagent method.

[0004] The Grignard reagent method uses chlorobenzene, magnesium powder and an organic solvent to prepare a Grignard reagent, which is then reacted with silicon tetrachloride to produce phenylchlorosilane. This method has high operational requirements during the preparation of the Grignard reagent, and improper control can easily lead to safety hazards such as explosion. It is not suitable for large-scale industrial production and is difficult to mass produce.

[0005] The direct method uses chlorobenzene and silicon powder as raw materials to generate phenylchlorosilane under the action of a catalyst.

[0006] (C6H5)CL+Si→(C6H5)SiCL3+(C6H5)2SiCL2+(C6H5)3SiCL+SiCL4+HCL

[0007] This method has been industrialized for mass production, but the by-products of the reaction, silicon tetrachloride and hydrogen chloride, cannot be further recycled and even become pollutants, resulting in low product yields and high raw material consumption.

[0008] The condensation method uses chlorobenzene and trichlorosilane as raw materials to directly synthesize phenylchlorosilane at high temperature.

[0009] (C6H5)CL+SiHCL3→(C6H5)SiCL3+HCL

[0010] (C6H5)CL+SiHCL3→C6H6+SiCL4

[0011] The raw material trichlorosilane of this method is expensive and difficult to obtain. At the same time, as in the direct method, the by-product silicon tetrachloride and hydrogen chloride are difficult to recycle, resulting in high raw material consumption and low product yield.

[0012] From the above content, it can be seen that the main synthesis method of phenylchlorosilane will produce a certain amount of silicon tetrachloride as a by-product, as well as impurities such as trichlorosilane, dichlorodihydrosilane, benzene, chlorobenzene, aluminum chloride, ferric chloride, copper chloride, zinc chloride, and boron chloride. If high-purity silicon tetrachloride can be produced by a certain method, waste can be turned into treasure, and the benzene and chlorobenzene therein can be reused. Summary of the invention

[0013] In view of this, the present invention provides a system and method for purifying crude silicon tetrachloride byproduct to produce high-purity silicon tetrachloride to solve the above technical problems.

[0014] The invention provides a system for purifying and preparing high-purity silicon tetrachloride from crude silicon tetrachloride byproducts. The system comprises a resin adsorption device, a lightness removal tower, a heaviness removal tower and a fine degassing device. The resin adsorption device is connected with an air inlet pipe for the crude silicon tetrachloride byproducts, a material outlet of the resin adsorption device is connected with a material inlet of the lightness removal tower, a light component removal pipe is connected with the top of the lightness removal tower, a material pipe connected with the bottom of the lightness removal tower is connected with the material inlet of the heaviness removal tower, a heavy component removal pipe is connected with the bottom of the heaviness removal tower, a material pipe at the top of the heaviness removal tower is connected with the material inlet of the fine degassing device, and a material outlet of the fine degassing device is connected with a high-purity silicon tetrachloride conveying pipe.

[0015] Wherein, the resin adsorption device is filled with benzene-specific adsorption resin.

[0016] Wherein, the light-removal tower and the heavy-removal tower are respectively connected with a reboiler.

[0017] Among them, the reflux ratio of the light-removal tower is 35-40, and the tower top pressure is 50kPa-100kPa; the reflux ratio of the heavy-removal tower is 32-40, and the tower top pressure is 30kPa-80kPa.

[0018] Wherein, the fine degassing device includes an adsorption tower body, an air inlet pipe 4-2 is provided at the lower part of the adsorption tower body, an air outlet pipe 4-3 is provided at the bottom of the adsorption tower, a plurality of partitions are provided in the adsorption tower body, an adsorption stuffing box is provided on the partition, two ends of the adsorption stuffing box are respectively connected to the air inlet branch pipe and the air outlet branch pipe, the air inlet branch pipe is connected to the air inlet pipe, the air outlet branch pipe is connected to the air outlet pipe 4-3, and a connecting pipe is provided between the air inlet pipe and the air outlet branch pipe of adjacent adsorption stuffing boxes; a first solenoid valve is provided on the air inlet pipe 4-2 between two adjacent air inlet branches, a second solenoid valve is provided on the air outlet pipe 4-3 between two adjacent air outlet branches, a third solenoid valve is provided on the air inlet branch pipe, and a fourth solenoid valve is provided on the air outlet branch pipe. According to the gas flow direction, the third solenoid valve is provided on the pipeline of the air inlet branch pipe between the air inlet pipe and the connecting pipe, the fourth solenoid valve is provided on the pipeline of the air outlet branch pipe between the air outlet pipe and the connecting pipe, and a fifth solenoid valve is provided on the connecting pipe.

[0019] There are three adsorption filling boxes, which are filled with benzene adsorption resin, metal adsorption resin and boron adsorption resin respectively.

[0020] The present invention also provides a method for preparing high-purity silicon tetrachloride using the above system, comprising the following steps:

[0021] (5) transporting the crude silicon tetrachloride byproduct to a resin adsorption device to adsorb benzene and regenerate and recover it;

[0022] (6) passing the material adsorbed by the resin adsorption device into a light component removal tower, and removing the light component from the top of the light component removal tower;

[0023] (7) The material at the bottom of the light removal tower is transported to the heavy removal tower, and the heavy components are removed from the bottom of the heavy removal tower;

[0024] (8) The material pipe at the top of the deweighting tower is transported to the fine deweighting device to remove the trace impurities contained in the silicon tetrachloride to prepare high-purity silicon tetrachloride.

[0025] Wherein, in step (1), the mass percentages of the components in the crude silicon tetrachloride by-product are as follows:

[0026] <![CDATA[SiH2Cl2]]> 0.1-1％ <![CDATA[SiHCl3]]> 0.2-2％ <![CDATA[SiCl4]]> 60-95％ <![CDATA[C6H6]]> 5-30％ <![CDATA[C5H5Cl]]> 0.1-2％ <![CDATA[BCl3]]> 20-200ppm <![CDATA[FeCl3]]> 20-200ppm <![CDATA[CuCl2]]> 20-200ppm <![CDATA[PCl3]]> 20-200ppm <![CDATA[AlCl3]]> 20-200ppm <![CDATA[ZnCl3]]> 20-200ppm

[0027] Wherein, in step (2), the light components removed from the top of the light-removal tower include trichlorosilane and dichlorosilane.

[0028] Wherein, in step (3), the heavy components removed from the bottom of the deweighting tower include chlorobenzene.

[0029] Wherein, the purity of the prepared high-purity silicon tetrachloride is not less than 99.99999999%.

[0030] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0031] The present invention adopts a regenerable resin adsorption device to adsorb benzene in the material and regenerate and recycle it, and then enters a set of rectification device, and removes light components such as trichlorosilane and dichlorodihydrosilane by setting a light removal tower, removes chlorobenzene and other impurities by setting a heavy removal tower, and finally sets a set of fine removal device to remove trace impurities contained in silicon tetrachloride to prepare 99.9999999% high-purity silicon tetrachloride. The process route of the present invention is simple, no chemical reaction occurs in the production process, and the introduction of new other impurities is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a process flow chart of a system for purifying crude silicon tetrachloride byproduct to produce high-purity silicon tetrachloride.

[0033] Figure 2 It is a schematic diagram of the structure of the fine stripping device in the present invention.

[0034] In the figure, 1. resin adsorption device, 2. light component removal tower, 3. heavy component removal tower, 4. fine desorption device, 4-1. adsorption tower body, 4-2. air inlet pipe, 4-3. air outlet pipe, 4-4. partition, 4-5. adsorption stuffing box, 4-6. air inlet branch pipe, 4-7. air outlet branch pipe, 4-8. connecting pipe, 4-9. first solenoid valve, 4-10. second solenoid valve, 4-11. third solenoid valve, 4-12. fourth solenoid valve, 4-13. fifth solenoid valve, 5. crude silicon tetrachloride by-product air inlet pipe, 6. light component removal pipe, 7. heavy component removal pipe, 8. high-purity silicon tetrachloride delivery pipe, 9. reboiler DETAILED DESCRIPTION

[0035] The following embodiments are provided for a better understanding of the present invention, but are not limited to the best mode of implementation, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0036] In the following embodiments, macroporous adsorption resin, benzene adsorption resin, metal adsorption resin and boron adsorption resin are all from Xi'an Lanxiao Technology New Materials Co., Ltd., among which the benzene adsorption resin is of the grade LSC-900, which has a good mesh structure and a high specific surface area, and can be mainly used to adsorb organic molecules such as benzene through the screening effect of pore size, intermolecular force, hydrogen bonding, etc. The grade of metal adsorption resin is LSC-830, which has a chelating group, and the chelating group forms a chelate with the metal, thereby separating it from silicon tetrachloride. The grade of boron adsorption resin is LSC-700, which has a chelating group, and combines with boron through hydrogen bonding, and has a high removal rate for boron trichloride.

[0037] Example 1

[0038] like Figure 2As shown, this embodiment provides a fine degassing device 4, which includes an adsorption tower body 4-1, an air inlet pipe 4-2 is provided at the lower part of the adsorption tower body 4-1, an air outlet pipe 4-3 is provided at the bottom of the adsorption tower, a plurality of partitions 4-4 are provided in the adsorption tower body, an adsorption stuffing box 4-5 is provided on the partition 4-4, and both ends of the adsorption stuffing box 4-5 are respectively connected to an air inlet branch pipe 4-6 and an air outlet branch pipe 4-7, the air inlet branch pipe 4-6 is connected to the air inlet pipe, the air outlet branch pipe 4-7 is connected to the air outlet pipe 4-3, and the air inlet pipes and air outlet branch pipes 4-7 of adjacent adsorption stuffing boxes 4-5 are connected by a connecting pipe 4- 8; A first solenoid valve 4-9 is provided on the air intake pipe 4-2 between two adjacent air intake branches 4-6, a second solenoid valve 4-10 is provided on the air outlet pipe 4-3 between two adjacent air outlet branches 4-7, a third solenoid valve 4-11 is provided on the air intake branch 4-6, a fourth solenoid valve 4-12 is provided on the air outlet branch 4-7, according to the gas flow direction, the third solenoid valve 4-11 is provided on the pipeline between the air intake pipe and the connecting pipe 4-8 of the air intake branch 4-6, the fourth solenoid valve 4-12 is provided on the pipeline between the air outlet pipe and the connecting pipe 4-8 of the air outlet branch 4-7, and a fifth solenoid valve 4-13 is provided on the connecting pipe. The first solenoid valve 4-9, the second solenoid valve 4-10, the third solenoid valve 4-11 and the fourth solenoid valve 4-12 can be automatically controlled by the control system, and which adsorption resins are selectively used for adsorption according to production needs and the content of each component in the crude silicon tetrachloride by-product.

[0039] There are three adsorption filling boxes 4-5, which are filled with benzene adsorption resin, metal adsorption resin and boron adsorption resin respectively. These three adsorption resins respectively adsorb and separate metal ions, boron chloride and benzene again, further improving the purity of silicon tetrachloride, so that the purity of silicon tetrachloride is not less than 99.9999999%.

[0040] Example 2

[0041] This embodiment provides a system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproducts, such as Figure 1 As shown, it includes a resin adsorption device 1, a light-removing tower 2, a heavy-removing tower 3 and a fine-removing device 4, the resin adsorption device 1 is connected to a crude silicon tetrachloride by-product inlet pipe 5, the discharge port of the resin adsorption device 1 is connected to the feed port of the light-removing tower 2, the top of the light-removing tower 2 is connected to a light component removal pipe 6, the material pipe connected to the bottom of the light-removing tower 2 is connected to the feed port of the heavy-removing tower 3, the bottom of the heavy-removing tower 3 is connected to a heavy component removal pipe 7, the material pipe at the top of the heavy-removing tower 3 is connected to the feed port of the fine-removing device 4, and the discharge port of the fine-removing device 4 is connected to a high-purity silicon tetrachloride conveying pipe 8.

[0042] The resin adsorption device 1 is filled with benzene-specific adsorption resin.

[0043] The light-removal tower 2 and the heavy-removal tower 3 are respectively connected to a reboiler 9.

[0044] Among them, the reflux ratio of the lightness removal tower 2 is 38, and the tower top pressure is 80kPa.

[0045] Wherein, the reflux ratio of the deweighting tower 3 is 36, and the tower top pressure is 55 kPa.

[0046] Example 2

[0047] This embodiment provides a system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproducts, such as Figure 1 As shown, it includes a resin adsorption device 1, a light-removing tower 2, a heavy-removing tower 3 and a fine-removing device 4, the resin adsorption device 1 is connected to a crude silicon tetrachloride by-product inlet pipe 5, the discharge port of the resin adsorption device 1 is connected to the feed port of the light-removing tower 2, the top of the light-removing tower 2 is connected to a light component removal pipe 6, the material pipe connected to the bottom of the light-removing tower 2 is connected to the feed port of the heavy-removing tower 3, the bottom of the heavy-removing tower 3 is connected to a heavy component removal pipe 7, the material pipe at the top of the heavy-removing tower 3 is connected to the feed port of the fine-removing device 4, and the discharge port of the fine-removing device 4 is connected to a high-purity silicon tetrachloride conveying pipe 8.

[0048] The resin adsorption device 1 is filled with benzene-specific adsorption resin.

[0049] The light-removal tower 2 and the heavy-removal tower 3 are respectively connected to a reboiler 9.

[0050] Wherein, the reflux ratio of the lightness removal tower 2 is 35, and the tower top pressure is 100 kPa.

[0051] Wherein, the reflux ratio of the deweighting tower 3 is 32, and the tower top pressure is 80 kPa.

[0052] Example 3

[0053] This embodiment provides a system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproducts, such as Figure 1 As shown, it includes a resin adsorption device 1, a light-removing tower 2, a heavy-removing tower 3 and a fine-removing device 4, the resin adsorption device 1 is connected to a crude silicon tetrachloride by-product inlet pipe 5, the discharge port of the resin adsorption device 1 is connected to the feed port of the light-removing tower 2, the top of the light-removing tower 2 is connected to a light component removal pipe 6, the material pipe connected to the bottom of the light-removing tower 2 is connected to the feed port of the heavy-removing tower 3, the bottom of the heavy-removing tower 3 is connected to a heavy component removal pipe 7, the material pipe at the top of the heavy-removing tower 3 is connected to the feed port of the fine-removing device 4, and the discharge port of the fine-removing device 4 is connected to a high-purity silicon tetrachloride conveying pipe 8.

[0054] The resin adsorption device 1 is filled with benzene-specific adsorption resin.

[0055] The light-removal tower 2 and the heavy-removal tower 3 are respectively connected to a reboiler 9.

[0056] Wherein, the reflux ratio of the lightness removal tower 2 is 40, and the tower top pressure is 50 kPa.

[0057] Wherein, the reflux ratio of the deweighting tower 3 is 40, and the tower top pressure is 30 kPa.

[0058] Example 4

[0059] This embodiment provides a method for preparing high-purity silicon tetrachloride using the system of embodiment 1, comprising the following steps:

[0060] (1) transporting the crude silicon tetrachloride byproduct to a resin adsorption device 1 to adsorb benzene and regenerate and recover it;

[0061] (2) passing the material adsorbed by the resin adsorption device 1 into the light-removal tower 2, and removing the light components from the top of the light-removal tower 2, wherein the removed light components include trichlorosilane and dichlorosilane;

[0062] (3) the material at the bottom of the light removal tower 2 is transported to the heavy removal tower 3, and the heavy components are removed from the bottom of the heavy removal tower 3; the removed heavy components include chlorobenzene;

[0063] (4) The material pipe at the top of the deweighting tower 3 is transported to the fine deweighting device 4 to remove the trace impurities contained in the silicon tetrachloride to prepare high-purity silicon tetrachloride with a purity of not less than 99.9999999%.

[0064] Among them, the content of product components in each step is as follows:

[0065]

[0066] Example 5

[0067] This embodiment provides a method for preparing high-purity silicon tetrachloride using the system of embodiment 2, comprising the following steps:

[0068] (1) transporting the crude silicon tetrachloride byproduct to a resin adsorption device 1 to adsorb benzene and regenerate and recover it;

[0069] (2) passing the material adsorbed by the resin adsorption device 1 into the light-removal tower 2, and removing the light components from the top of the light-removal tower 2, wherein the removed light components include trichlorosilane and dichlorosilane;

[0070] (3) the material at the bottom of the light removal tower 2 is transported to the heavy removal tower 3, and the heavy components are removed from the bottom of the heavy removal tower 3; the removed heavy components include chlorobenzene;

[0071] (4) The material pipe at the top of the deweighting tower 3 is transported to the fine deweighting device 4 to remove the trace impurities contained in the silicon tetrachloride to prepare high-purity silicon tetrachloride with a purity of not less than 99.9999999%.

[0072] Wherein, in step (1), the mass percentages of the components in the crude silicon tetrachloride by-product are as follows:

[0073]

[0074] Example 6

[0075] This embodiment provides a method for preparing high-purity silicon tetrachloride using the system of embodiment 3, comprising the following steps:

[0076] (1) transporting the crude silicon tetrachloride byproduct to a resin adsorption device 1 to adsorb benzene and regenerate and recover it;

[0077] (2) passing the material adsorbed by the resin adsorption device 1 into the light-removal tower 2, and removing the light components from the top of the light-removal tower 2, wherein the removed light components include trichlorosilane and dichlorosilane;

[0078] (3) the material at the bottom of the light removal tower 2 is transported to the heavy removal tower 3, and the heavy components are removed from the bottom of the heavy removal tower 3; the removed heavy components include chlorobenzene;

[0079] (4) The material pipe at the top of the deweighting tower 3 is transported to the fine deweighting device 4 to remove the trace impurities contained in the silicon tetrachloride to prepare high-purity silicon tetrachloride with a purity of not less than 99.9999999%.

[0080] Wherein, in step (1), the mass percentages of the components in the crude silicon tetrachloride by-product are as follows:

[0081]

[0082] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. The protection scope of the present invention is defined by the claims and their equivalent technical solutions.

Claims

1. A system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproducts, characterized in that: It comprises a resin adsorption device, a light-removing tower, a heavy-removing tower and a fine-removing device, wherein the resin adsorption device is connected to an air inlet pipe for a crude silicon tetrachloride byproduct, the discharge port of the resin adsorption device is connected to a feed port of the light-removing tower, the top of the light-removing tower is connected to a light component removal pipe, the material pipe connected to the bottom of the light-removing tower is connected to the feed port of the heavy-removing tower, the bottom of the heavy-removing tower is connected to a heavy component removal pipe, the material pipe at the top of the heavy-removing tower is connected to the feed port of the fine-removing device, and the discharge port of the fine-removing device is connected to a high-purity silicon tetrachloride conveying pipe.

2. A system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproduct according to claim 1, characterized in that: The resin adsorption device is filled with benzene adsorption resin.

3. A system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproduct according to claim 1, characterized in that: The light-removal tower and the heavy-removal tower are respectively connected with a reboiler.

4. A system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproduct according to claim 1, characterized in that: The reflux ratio of the light-removal tower is 35-40, and the tower top pressure is 50 kPa-100 kPa; the reflux ratio of the heavy-removal tower is 32-40, and the tower top pressure is 30 kPa-80 kPa.

5. A system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproduct according to claim 1, characterized in that: The degassing device comprises an adsorption tower body, an air inlet pipe is provided at the lower part of the adsorption tower body, an air outlet pipe is provided at the bottom of the adsorption tower, a plurality of partitions are provided in the adsorption tower body, an adsorption stuffing box is provided on the partition, two ends of the adsorption stuffing box are respectively connected to an air inlet branch pipe and an air outlet branch pipe, the air inlet branch pipe is connected to the air inlet pipe, the air outlet branch pipe is connected to the air outlet pipe, and a connecting pipe is connected between the air inlet pipe and the air outlet branch pipe of adjacent adsorption stuffing boxes; a first solenoid valve is provided on the air inlet pipe between two adjacent air inlet branches, a second solenoid valve is provided on the air outlet pipe between two adjacent air outlet branches, a third solenoid valve is provided on the air inlet branch pipe, and a fourth solenoid valve is provided on the air outlet branch pipe. According to the gas flow direction, the third solenoid valve is provided on the pipeline of the air inlet branch pipe between the air inlet pipe and the connecting pipe, the fourth solenoid valve is provided on the pipeline of the air outlet branch pipe between the air outlet pipe and the connecting pipe, and a fifth solenoid valve is provided on the connecting pipe.

6. A system for purifying high-purity silicon tetrachloride from crude silicon tetrachloride byproduct according to claim 5, characterized in that: There are four adsorption filling boxes, which are filled with benzene adsorption resin, metal adsorption resin and boron adsorption resin respectively.

7. A method for preparing high-purity silicon tetrachloride using the system according to any one of claims 1 to 6, characterized in that The steps include: (1) transporting the crude silicon tetrachloride byproduct to a resin adsorption device to adsorb benzene and regenerate and recover it; (2) passing the material adsorbed by the resin adsorption device into a light component removal tower, and removing the light component from the top of the light component removal tower; (3) The material at the bottom of the light removal tower is transported to the heavy removal tower, and the heavy components are removed from the bottom of the heavy removal tower; (4) The material pipe at the top of the deweighting tower is transported to the fine deweighting device to remove the trace impurities contained in the silicon tetrachloride to prepare high-purity silicon tetrachloride.

8. The method for preparing high-purity silicon tetrachloride according to claim 7, characterized in that: In step (1), the mass percentages of the components in the crude silicon tetrachloride by-product are as follows:

9. The method for preparing high-purity silicon tetrachloride according to claim 7, wherein: The light components removed from the top of the light removal tower include trichlorosilane and dichlorosilane; the heavy components removed from the bottom of the heavy removal tower include chlorobenzene.

10. The method for preparing high-purity silicon tetrachloride according to claim 7, characterized in that: The purity of the prepared high-purity silicon tetrachloride is not less than 99.99999999%.

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