Dichlorosilane classified recycling system
By designing a dichlorodihydrogen silicon classification recycling system in the polycrystalline silicon production process, and carrying out anti-disproportionation reactions on hydrogenated materials and reducing materials respectively, the problem of high cost and energy consumption of dichlorodihydrogen silicon purification and separation equipment in the prior art is solved. , achieving the effect of reducing costs and improving conversion rates.
Patent Information
- Application Number
- CN202421056876.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-05-15
AI Technical Summary
During the existing polysilicon production process, the purification and separation of dichlorodihydrogen silicon requires anti-disturbing material distillation units, resulting in an increase in equipment investment costs and increased energy consumption.
A dichlorodihydrogen silicon sorting recycling system was designed, and the anti-dispersation reaction was carried out through hydrogenation materials and reducing material recovery components respectively. The resulting silicon tetrachloride, trichlorosil and dichlorosilic silicon mixed materials were returned to their respective systems. Perform cyclic purification and separation to avoid the use of anti-dispersive material distillation units.
It reduces equipment investment costs and energy consumption, improves reaction conversion rates, and realizes the recycling and utilization of by-products.
Smart Images
Figure CN222305755U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of polysilicon production equipment, in particular to a dichlorosilane classification circulation recovery system. Background Art
[0002] In the production process of polysilicon by the modified Siemens process, the cold hydrogenation reaction of silicon tetrachloride utilizes the high temperature of silicon tetrachloride and the thermal decomposition and hydrogenation reaction under the action of a catalyst to obtain trichlorosilane. The byproduct hydrogen chloride produced then undergoes a chain reaction with industrial silicon powder, and the byproduct dichlorosilane is generated in the process. The chemical reaction equation is summarized as: 3SiCl4+2H2+2Si+2HCl=4SiHCl3+SiH2Cl2. The reaction conversion rate of silicon tetrachloride in the cold hydrogenation system is about 25%, and the main components of the reaction material are a mixture of trichlorosilane, silicon tetrachloride, and dichlorosilane. The byproduct dichlorosilane separated by the hydrogenation material crude distillation unit is called hydrogenated dichlorosilane. The production process of hydrogenated dichlorosilane is due to the participation of industrial silicon powder with a high impurity content, resulting in a high impurity content. The trichlorosilane hydrogenation reduction reaction uses refined trichlorosilane products and high-purity hydrogen to enter the reduction furnace in a certain proportion. At a high temperature of 1050-1100°C, trichlorosilane is reduced by hydrogen, and the generated silicon is deposited on the silicon core of the heating element. The chemical reaction equation is summarized as: 3SiHCl3+H2=Si+SiCl4+SiH2Cl2+3HCl. The reaction conversion rate of trichlorosilane in the trichlorosilane hydrogenation reduction reaction is about 11%. The main components of the materials after the reaction are also a mixture of trichlorosilane, silicon tetrachloride, and dichlorosilane. The by-product dichlorosilane separated by the reduction raw material distillation unit is called the reduction raw material dichlorosilane. The production process of the reduction raw material dichlorosilane is produced in a high-purity reduction system, so its impurity content is relatively low. The anti-disproportionation reaction of dichlorosilane is to react with silicon tetrachloride under the action of a catalyst: SiH2Cl2+SiCl4=2SiHCl3, thereby converting into trichlorosilane, which is refined and then hydrogen reduced to produce polysilicon.
[0003] The existing method is to combine the hydrogenated material dichlorosilane and the reduced material dichlorosilane, and then mix them with silicon tetrachloride and enter the same anti-disproportionation reactor. The mixed material of trichlorosilane, silicon tetrachloride and dichlorosilane after the reaction needs to be arranged with an anti-disproportionation material distillation unit to purify and separate various materials. The arrangement of the anti-disproportionation material distillation unit increases the equipment investment cost and increases the energy consumption of the production process. Utility Model Content
[0004] In view of this, an embodiment of the utility model provides a dichlorosilane classification circulation recovery system, the main purpose of which is to provide a dichlorosilane classification circulation recovery system that can reduce energy consumption and production costs and recycle by-products.
[0005] In order to achieve the above purpose, the utility model mainly provides the following technical solutions:
[0006] The present invention provides a system for recycling dichlorosilane, which comprises:
[0007] A hydrogenated material recovery component, the hydrogenated material recovery component comprising a first crude distillation tower, a second crude distillation tower, a first reactor and a first feed pipeline, the top of the first crude distillation tower is connected to the feed end of the second crude distillation tower, the bottom of the second crude distillation tower is connected to the feed end of the first crude distillation tower, both ends of the first feed pipeline are respectively connected to the top of the second crude distillation tower and the feed end of the first reactor, and the top of the first reactor is connected to the feed end of the first crude distillation tower;
[0008] A raw material recovery component comprises a first distillation tower, a second distillation tower, a second reactor, a second feed pipe and a mixing pipe, the top of the first distillation tower is connected to the feed end of the second distillation tower, the bottom of the second distillation tower is connected to the feed end of the first distillation tower, the two ends of the second feed pipe are respectively connected to the top of the second distillation tower and the feed end of the second reactor, the top of the second reactor is connected to the feed end of the first distillation tower, one end of the mixing pipe is connected to the middle of the first distillation tower, and the other end is respectively connected to the first feed pipe and the second feed pipe.
[0009] Furthermore, the hydrogenated material recovery component also includes a first conveying pipeline, a first return pipeline and a second return pipeline, the first conveying pipeline is connected to the feed end of the first crude distillation tower, the two ends of the first return pipeline are respectively connected to the bottom end of the second crude distillation tower and the first conveying pipeline, and the two ends of the second return pipeline are respectively connected to the top of the first reactor and the first conveying pipeline.
[0010] Furthermore, the raw material recovery component also includes a second conveying pipeline, a third return pipeline and a fourth return pipeline, the second conveying pipeline is connected to the feed end of the first distillation tower, the two ends of the third return pipeline are respectively connected to the bottom end of the second distillation tower and the second conveying pipeline, and the two ends of the fourth return pipeline are respectively connected to the top of the second reactor and the second conveying pipeline.
[0011] Furthermore, the operating pressure in the first crude distillation tower is 0.1-0.2Mpa, and the top temperature of the first crude distillation tower is 50-65°C; the operating pressure in the second crude distillation tower is 0.2-0.3Mpa, and the top temperature of the second crude distillation tower is 40-50°C.
[0012] Furthermore, the operating pressure in the first distillation tower is 0.5-0.6Mpa, the top temperature of the first distillation tower is 90-100°C, the operating pressure in the second distillation tower is 0.4-0.5Mpa, and the top temperature of the second distillation tower is 60-70°C.
[0013] Furthermore, the operating pressure of the first reactor and the second reactor is 0.2-0.4 MPa, and the operating temperature is 50-70°C.
[0014] Furthermore, a slurry recovery component is provided, and the slurry recovery component is connected to the bottom of the first crude distillation tower and the bottom of the first rectifying tower respectively.
[0015] Compared with the prior art, the utility model has the following technical effects:
[0016] In the technical solution provided by the embodiment of the present utility model, the function of the hydrogenation material recovery component is to purify and separate the hydrogenation material dichlorosilane, and the hydrogenation material recovery component includes a first crude distillation tower, a second crude distillation tower, a first reactor and a first feed pipeline, the top of the first crude distillation tower is connected to the feed end of the second crude distillation tower, the bottom of the second crude distillation tower is connected to the feed end of the first crude distillation tower, the two ends of the first feed pipeline are respectively connected to the top of the second crude distillation tower and the feed end of the first reactor, and the top of the first reactor is connected to the feed end of the first crude distillation tower; the function of the reduction raw material recovery component is to purify and separate the reduction raw material dichlorosilane, and the reduction raw material recovery component includes a first distillation tower, a second distillation tower, a second reactor, a second feed pipeline and a mixing pipeline, the top of the first distillation tower is connected to the feed end of the second distillation tower, the bottom of the second distillation tower is connected to the feed end of the first distillation tower, and the two ends of the second feed pipeline are respectively connected to the top of the second distillation tower and the feed end of the second reactor. end, the top of the second reactor is connected to the feed end of the first distillation tower, one end of the mixing pipeline is connected to the middle of the first distillation tower, and the other end is respectively connected to the first feed pipeline and the second feed pipeline. Compared with the prior art, the hydrogenated material dichlorosilane and the reduced material dichlorosilane are combined, then mixed with silicon tetrachloride, and enter the same anti-disproportionation reactor. After the reaction, the trichlorosilane, silicon tetrachloride, and dichlorosilane mixture needs to be arranged with an anti-disproportionation material distillation unit to purify and separate various materials. The arrangement of the anti-disproportionation material distillation unit increases the equipment investment cost and increases the energy consumption of the production process. In the present technical solution, the hydrogenated material dichlorosilane and the reduced material dichlorosilane with different impurity contents are reacted in anti-disproportionation reactors respectively, and the generated silicon tetrachloride, trichlorosilane and dichlorosilane mixture are returned to their respective systems, and then circulated for purification and separation, which can not only save and reduce equipment costs and energy consumption, but also recycle by-products, thereby achieving the technical effect of improving the conversion rate of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 A schematic structural diagram of a dichlorosilane classification, recycling and recovery system provided in an embodiment of the utility model. DETAILED DESCRIPTION
[0018] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0019] like Figure 1 As shown, the embodiment of the utility model provides a dichlorosilane classification circulation recovery system, which includes:
[0020] A hydrogenated material recovery component, the hydrogenated material recovery component comprises a first crude distillation tower 11, a second crude distillation tower 12, a first reactor 13 and a first feed pipeline 14, the top of the first crude distillation tower 11 is connected to the feed end of the second crude distillation tower 12, the bottom of the second crude distillation tower 12 is connected to the feed end of the first crude distillation tower 11, the two ends of the first feed pipeline 14 are respectively connected to the top of the second crude distillation tower 12 and the feed end of the first reactor 13, and the top of the first reactor 13 is connected to the feed end of the first crude distillation tower 11;
[0021] A raw material recovery component includes a first distillation tower 21, a second distillation tower 22, a second reactor 23, a second feed pipe 24 and a mixing pipe 25, wherein the top of the first distillation tower 21 is connected to the feed end of the second distillation tower 22, the bottom of the second distillation tower 22 is connected to the feed end of the first distillation tower 21, the two ends of the second feed pipe 24 are respectively connected to the top of the second distillation tower 22 and the feed end of the second reactor 23, the top of the second reactor 23 is connected to the feed end of the first distillation tower 21, one end of the mixing pipe 25 is connected to the middle part of the first distillation tower 21, and the other end is respectively connected to the first feed pipe 14 and the second feed pipe 24.
[0022] In the technical solution provided in the embodiment of the present utility model, the function of the hydrogenated material recovery component is to purify and separate the hydrogenated material dichlorodisilane, and the hydrogenated material recovery component includes a first crude distillation tower 11, a second crude distillation tower 12, a first reactor 13 and a first feed pipeline 14, the top of the first crude distillation tower 11 is connected to the feed end of the second crude distillation tower 12, the bottom of the second crude distillation tower 12 is connected to the feed end of the first crude distillation tower 11, and the two ends of the first feed pipeline 14 are respectively connected to the top of the second crude distillation tower 12 and the feed end of the first reactor 13. The top end of the first reactor 13 is connected to the feed end of the first crude distillation tower 11; the function of the raw material recovery component is to purify and separate the raw material dichlorodihydrosilane, and the raw material recovery component includes a first distillation tower 21, a second distillation tower 22, a second reactor 23, a second feed pipeline 24 and a mixing pipeline 25, the top end of the first distillation tower 21 is connected to the feed end of the second distillation tower 22, the bottom end of the second distillation tower 22 is connected to the feed end of the first distillation tower 21, and both ends of the second feed pipeline 24 are respectively connected to the second distillation tower 21. The top of the tower 22 and the feed end of the second reactor 23, the top of the second reactor 23 is connected to the feed end of the first distillation tower 21, one end of the mixing pipeline 25 is connected to the middle of the first distillation tower 21, and the other end is connected to the first feed pipeline 14 and the second feed pipeline 24 respectively. Compared with the prior art, the hydrogenated material dichlorosilane and the reduced material dichlorosilane are combined, and then mixed with silicon tetrachloride and enter the same anti-disproportionation reactor. The reaction of trichlorosilane, silicon tetrachloride, and dichlorosilane mixture needs to be arranged for anti-disproportionation. The distillation unit purifies and separates various materials. The arrangement of the anti-disproportionated material distillation unit increases the equipment investment cost and the energy consumption of the production process. In the present technical scheme, the hydrogenated material dichlorosilane with different impurity contents and the reducing material dichlorosilane are respectively reacted in the anti-disproportionated reactor, and the resulting mixture of silicon tetrachloride, trichlorosilane and dichlorosilane is returned to their respective systems, and then circulated for purification and separation, which can not only save and reduce equipment costs and energy consumption, but also recycle by-products, thereby achieving the technical effect of improving the conversion rate of the reaction.
[0023] The function of the hydrogenated material recovery component is to purify and separate the hydrogenated material dichlorosilane. The hydrogenated material recovery component includes a first crude distillation tower 11, a second crude distillation tower 12, a first reactor 13 and a first feed pipeline 14. The top of the first crude distillation tower 11 is connected to the feed end of the second crude distillation tower 12, the bottom of the second crude distillation tower 12 is connected to the feed end of the first crude distillation tower 11, and the two ends of the first feed pipeline 14 are respectively connected to the top of the second crude distillation tower 12 and the feed end of the first reactor 13. The top of 13 is connected to the feed end of the first crude distillation tower 11, the top of the first crude distillation tower 11 produces a mixed chlorosilane of trichlorosilane and dichlorodihydrosilane and enters the middle of the second crude distillation tower 12, the bottom of the first crude distillation tower 11 produces high-boiling heavy impurities to the slurry recovery component 3 for recycling, the feed end of the first crude distillation tower 11 is provided with a first conveying pipeline 15, the liquid chlorosilane condensed from the cold hydrogenation reaction system enters the first crude distillation tower 11 from the first conveying pipeline 15, the side of the first crude distillation tower 11 produces silicon tetrachloride and enters the cold hydrogenation reaction system for reuse, The operating pressure in the first crude distillation tower 11 is 0.1-0.2Mpa, the top temperature of the first crude distillation tower 11 is 50-65°C, the reflux feed ratio is 2:4, the theoretical stage is 90-120, the by-product hydrogenated material dichlorosilane is extracted from the top of the second crude distillation tower 12 and enters the first reactor 13, the heavy impurities extracted from the bottom of the second crude distillation tower 12 are returned to the first conveying pipeline 15 through the first return pipeline 16, and then enter the first crude distillation tower 11 for recycling, and the trichlorosilane extracted from the middle of the second crude distillation tower 12 enters the high-purity trichlorosilane rectification unit The first reactor 13 is further purified to obtain trichlorosilane, which is then transported to the reduction reaction equipment for reduction reaction. The operating pressure in the second crude distillation tower 12 is 0.2-0.3Mpa, the top temperature of the second crude distillation tower 12 is 40-50°C, the reflux feed ratio is 3:5, the theoretical stage is 130-160, and the top of the first reactor 13 returns the reacted mixed chlorosilane to the first transport pipeline 15 through the second return pipeline 17, and then enters the first crude distillation tower 11 for recycling treatment. The operating pressure of the first reactor 13 is 0.2-0.4MPa, operating temperature 50-70°C; the function of the reducing raw material recovery component is to purify and separate the reducing raw material dichlorodisilane, and the reducing raw material recovery component includes a first distillation tower 21, a second distillation tower 22, a second reactor 23, a second feed pipeline 24 and a mixing pipeline 25, the top of the first distillation tower 21 is connected to the feed end of the second distillation tower 22, the bottom of the second distillation tower 22 is connected to the feed end of the first distillation tower 21, the two ends of the second feed pipeline 24 are respectively connected to the top of the second distillation tower 22 and the feed end of the second reactor 23, the top of the second reactor 23 is connected to the feed end of the first distillation tower 21, and the mixing pipeline 2 One end of the first distillation tower 21 is connected to the middle of the first distillation tower 21, and the other end is connected to the first feed pipeline 14 and the second feed pipeline 24 respectively. The feed end of the first distillation tower 21 is installed with a second delivery pipeline 26. The liquid chlorosilane recovered from the tail gas of the reduction reaction enters the first distillation tower 21 through the second delivery pipeline 26. The mixed chlorosilane of trichlorosilane and dichlorodihydrosilane produced at the top of the first distillation tower 21 enters the second distillation tower 22 for further separation. The high-boiling heavy impurities produced at the bottom of the first distillation tower 21 enter the slurry recovery component 3 for recovery and treatment. The operating pressure in the first distillation tower 21 is 0.5-0.6Mpa, and the top temperature of the first distillation tower 21 is 90-10 0℃, reflux feed ratio 2:4, theoretical stage 110-140, the by-product dichlorosilane is taken out from the top of the second distillation tower 22 and enters the second reactor 23 for reaction, the heavy impurities are taken out from the bottom of the second distillation tower 22 and enter the second conveying pipeline 26 through the third return pipe 27, and then enter the first distillation tower 21 for recovery treatment, the high-purity trichlorosilane is taken out from the middle of the second distillation tower 22 and conveyed to the reduction reaction equipment for reduction reaction, the operating pressure in the second distillation tower 22 is 0.4-0.5Mpa, the top temperature of the second distillation tower 22 is 60-70℃, the reflux feed ratio is 3:5, the theoretical stage 120-150, the top of the second reactor 23 is passed through the fourth return pipe The material pipeline 28 returns the reacted mixed chlorosilane to the second delivery pipeline 26, and then enters the first distillation tower for recycling treatment. The operating pressure of the second reactor 23 is 0.2-0.4MPa, and the operating temperature is 50-70℃. In this technical solution, the hydrogenated material dichlorosilane and the reduced material dichlorosilane with different impurity contents are respectively subjected to the anti-disproportionation reactor for reaction, and the resulting silicon tetrachloride, trichlorosilane and dichlorosilane mixture are returned to their respective systems, and then circulated for purification and separation, saving the anti-disproportionation material distillation unit, which can effectively reduce the equipment investment cost, reduce the energy consumption of the production process, reduce the production cost, and realize the closed-loop circulation of the system and the recycling of by-products. .
[0024] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.
Claims
1. A classification and recycling system for dichlorosilane, characterized in that: include: A hydrogenated material recovery component, the hydrogenated material recovery component comprising a first crude distillation tower, a second crude distillation tower, a first reactor and a first feed pipeline, the top of the first crude distillation tower is connected to the feed end of the second crude distillation tower, the bottom of the second crude distillation tower is connected to the feed end of the first crude distillation tower, both ends of the first feed pipeline are respectively connected to the top of the second crude distillation tower and the feed end of the first reactor, and the top of the first reactor is connected to the feed end of the first crude distillation tower; A raw material recovery component comprises a first distillation tower, a second distillation tower, a second reactor, a second feed pipe and a mixing pipe, the top of the first distillation tower is connected to the feed end of the second distillation tower, the bottom of the second distillation tower is connected to the feed end of the first distillation tower, the two ends of the second feed pipe are respectively connected to the top of the second distillation tower and the feed end of the second reactor, the top of the second reactor is connected to the feed end of the first distillation tower, one end of the mixing pipe is connected to the middle of the first distillation tower, and the other end is respectively connected to the first feed pipe and the second feed pipe.
2. A dichlorosilane classification and recycling system according to claim 1, characterized in that: The hydrogenated material recovery component also includes a first conveying pipeline, a first return pipeline and a second return pipeline, the first conveying pipeline is connected to the feed end of the first crude distillation tower, the two ends of the first return pipeline are respectively connected to the bottom end of the second crude distillation tower and the first conveying pipeline, and the two ends of the second return pipeline are respectively connected to the top of the first reactor and the first conveying pipeline.
3. A dichlorosilane classification, recycling and recovery system according to claim 2, characterized in that: The reducing material recovery component also includes a second conveying pipeline, a third return pipeline and a fourth return pipeline, the second conveying pipeline is connected to the feed end of the first distillation tower, the two ends of the third return pipeline are respectively connected to the bottom end of the second distillation tower and the second conveying pipeline, and the two ends of the fourth return pipeline are respectively connected to the top of the second reactor and the second conveying pipeline.
4. A dichlorosilane classification, recycling and recovery system according to any one of claims 1 to 3, characterized in that: The operating pressure in the first crude distillation tower is 0.1-0.2Mpa, and the top temperature of the first crude distillation tower is 50-65°C. The operating pressure in the second crude distillation tower is 0.2-0.3Mpa, and the top temperature of the second crude distillation tower is 40-50°C.
5. A dichlorosilane classification, recycling and recovery system according to claim 4, characterized in that: The operating pressure in the first distillation tower is 0.5-0.6Mpa, and the top temperature of the first distillation tower is 90-100°C. The operating pressure in the second distillation tower is 0.4-0.5Mpa, and the top temperature of the second distillation tower is 60-70°C.
6. A dichlorosilane classification and recycling system according to claim 5, characterized in that: The operating pressure of the first reactor and the second reactor is 0.2-0.4 MPa, and the operating temperature is 50-70°C.
7. A dichlorosilane classification, recycling and recovery system according to any one of claims 1 to 3, characterized in that: Also includes: A slurry recovery component is connected to the bottom of the first crude distillation tower and the bottom of the first rectifying tower respectively.