A reactive distillation apparatus for chlorosilane disproportionation

Abstract

The utility model discloses a kind of reaction rectification equipment for chlorosilane disproportionation, it is related to methylsilane preparation technical field, the separation of silicon tetrachloride is realized in first separation section, the forced upshift of unreacted material, intensification reaction;First cooler forces heavy component downshift and participates in reaction;Second reboiler forces the target product dichlorosilane of first reaction rectification tower reaction to upshift to second reaction rectification tower reaction;Third separation section also intensifies the separation of component, downshift trichlorosilane, dichlorosilane and monochlorosilane etc. Upshift forced reaction;Third condenser also forces the separation of component, condenses heavy boiling point chlorosilane into liquid phase forced reaction;Second separation section separates heavy component and reacts again;Second condenser realizes forced reflux.The utility model has simplified process, simplifies equipment, improves the conversion rate of reaction, reduces energy consumption.

Description

Technical Field

[0001] This utility model belongs to the field of silane preparation technology, specifically relating to a reactive distillation device for the disproportionation of chlorosilanes. Background Technology

[0002] Silane, also known as silane or hydride, is a colorless, extremely flammable gas with the chemical formula SiH4. It is easily purified and can be precisely controlled, earning it the title of "flowing pure silicon." It is the core raw material for the silane method of producing high-purity crystalline silicon and an important electronic specialty gas that cannot be replaced by other silicon sources. It is widely used in TFT / LCDs, crystalline silicon solar cells, semiconductors, and emerging fields such as silicon-carbon anodes and advanced ceramics. Silane practically dominates the entire new energy, semiconductor, and new materials industries.

[0003] There are two main methods for disproportionation of chlorosilanes: fixed bed and reactive distillation. Fixed bed has a simple structure and the catalyst is easy to load, but the conversion rate is low and the energy consumption is high. Reactive distillation integrates the reaction catalyst with the distillation column structure, which quickly separates the reactants and forces the reaction in a direction that is conducive to conversion, resulting in higher conversion efficiency. However, reactive distillation equipment is complex, with the distillation separation section and the catalytic section fixed in an integrated device, resulting in a longer equipment length and higher investment.

[0004] The disproportionation method for chlorosilanes can use trichlorosilane or dichlorosilane as raw materials. A disproportionation reaction occurs under the catalysis of a catalyst. According to the mainstream methods for producing chlorosilane raw materials, silicon powder is used as a raw material. The chlorosilane produced by the hydrogenation reaction is mainly trichlorosilane. The disproportionation of trichlorosilane to silane mainly involves the following steps: Reaction 1: 2SiHCl3 → SiH2Cl2 + SiCl4; Reaction 2: 2 SiH2Cl2 → SiHCl3 + SiH3Cl; Reaction 3: 2 SiH3Cl --- SiH4 + SiH2Cl2; The conversion efficiency of reaction 1 is relatively low, and even under suitable operating conditions, the conversion rate is generally <20%. Reaction 2 has a higher conversion efficiency, and the conversion rate can be >40% under favorable operating conditions. Since SiH3Cl is unstable, reaction 3 is more easily generated.

[0005] Based on the complexity of the chlorosilane reaction equations, chlorosilane disproportionation reactive distillation can currently be divided into one-step and two-step methods. The one-step method integrates distillation and catalysis into a single column. Due to the limitations of the column structure, the conversion rate is relatively low, and a large amount of unreacted recycled material is collected along with the product. The unreacted material is separated by distillation and returned to the reactive distillation column for further reaction. The reactive distillation column has a complex structure, and the reaction must be carried out under designed conditions. Changes in reaction conditions can cause mismatches between reaction stages, thus affecting reaction efficiency. The two-step method utilizes the characteristics of the reaction. Reaction 1 occurs in a single reactive distillation column. The reactants are separated by the distillation column, and the feedstocks for reactions 2 and 3 are sent to a second-stage reactive distillation column for further reaction. The reactants are separated to obtain the product, while the unreacted and reacted products are used as feedstock for reaction 1. The two-step method, due to the multiple reaction and separation columns, has higher energy consumption than the one-step method. Utility Model Content

[0006] The purpose of this invention is to solve the problems of existing technologies and provide a reactive distillation apparatus for the disproportionation of chlorosilanes. The first separation section of the first reactive distillation column separates silicon tetrachloride and forces unreacted materials upwards to enhance the reaction. The first cooler of the first reactive distillation column forces heavy components downwards to participate in the reaction. The second reboiler of the second reactive distillation column forces the target product dichlorosilane from the first reactive distillation column upwards to react in the second reactive distillation column. The third separation section of the second reactive distillation column also enhances component separation, moving trichlorosilane downwards and forcing dichlorosilane and monochlorosilane upwards to react. The third condenser of the second reactive distillation column also forces component separation, condensing the reboiling-point chlorosilane into a liquid phase for forced reaction. The second separation section of the second reactive distillation column separates heavy components for further reaction. The second condenser of the second reactive distillation column achieves forced reflux. This invention simplifies the process, simplifies the equipment, improves the reaction conversion rate, and reduces energy consumption.

[0007] This utility model is achieved through the following technical solution: A reactive distillation apparatus for the disproportionation of chlorosilanes includes a first reactive distillation column and a second reactive distillation column. The first reactive distillation column contains, from top to bottom, a first condenser, a first reaction section, and a first separation section. The first reactive distillation column is equipped with a chlorosilane feed pipe, a first top outlet pipe, and a first bottom outlet pipe. The first bottom outlet pipe is equipped with a first bottom reflux pipe and a tetrachlorosilane outlet pipe. The first bottom reflux pipe is equipped with a first reboiler, which is connected to the first reactive distillation column via a second bottom reflux pipe. The first top outlet pipe is connected to the second reactive distillation column. The first reactive distillation column is connected to a first reactive distillation column. From top to bottom, the second reactive distillation column contains a second condenser, a second separation section, a second reaction section, and a third separation section. The second reactive distillation column is equipped with a silane discharge pipe, a side discharge pipe, a side reflux pipe, and a second reboiler discharge pipe. A third condenser is located between the side discharge pipe and the side reflux pipe. The second reboiler discharge pipe is connected to the first reactive distillation column via a fourth reboiler reflux pipe.

[0008] Preferably, the connection between the chlorosilane feed pipe and the first reactive distillation column, and the connection between the connecting pipe and the first reactive distillation column, are both located between the first reaction section and the first condenser.

[0009] Preferably, the connection between the first top discharge pipe and the second reactive distillation column is located on the side wall of the second reactive distillation column at the lower end of the third separation section.

[0010] Preferably, the connection between the side discharge pipe and the side reflux pipe and the second reactive distillation column is located between the second separation section and the second reaction section.

[0011] Preferably, the first condenser is provided with a first refrigerant inlet pipe and a first refrigerant outlet pipe.

[0012] Preferably, the first reboiler is provided with a first heat medium feed pipe and a first heat medium discharge pipe.

[0013] Preferably, the second condenser is provided with a second refrigerant inlet pipe and a second refrigerant outlet pipe.

[0014] Preferably, the second reboiler is provided with a second heat medium feed pipe and a second heat medium discharge pipe.

[0015] Preferably, the third condenser is provided with a third refrigerant inlet pipe and a third refrigerant outlet pipe.

[0016] Preferably, a transfer pump is provided on the connecting pipe.

[0017] Compared with the prior art, this utility model has the following advantages and beneficial effects: I. This utility model provides a reactive distillation apparatus for the disproportionation of chlorosilanes. The first separation section of the first reactive distillation column separates silicon tetrachloride, forcibly moving unreacted materials upwards to enhance the reaction. The first cooler of the first reactive distillation column forces heavy components downwards to participate in the reaction. The second reboiler of the second reactive distillation column forces the target product dichlorosilane from the first reactive distillation column upwards to react in the second reactive distillation column. The third separation section of the second reactive distillation column also enhances component separation, moving trichlorosilane downwards and forcing dichlorosilane and monochlorosilane upwards to react. The third condenser of the second reactive distillation column also forces component separation, condensing the reboiling-point chlorosilane into a liquid phase for forced reaction. The second separation section of the second reactive distillation column separates heavy components for further reaction. The second condenser of the second reactive distillation column achieves forced reflux. This utility model simplifies the process, simplifies equipment, improves reaction conversion rate, and reduces energy consumption.

[0018] II. The present invention provides a reactive distillation device for disproportionation of chlorosilane. The chlorosilane added through the chlorosilane feed pipe is separated from the trichlorosilane in the third separation section of the second reactive distillation column by the separation action of the third separation section. This allows the trichlorosilane from the first reactive distillation column to be added between the first reaction section and the first condenser, so that the disproportionation reaction (mainly reaction 1 occurs, and reaction 2 occurs in a small amount) is more effective.

[0019] III. The reactive distillation equipment for disproportionation of chlorosilane provided by this utility model improves the overall conversion rate and reduces the overall energy consumption level through the optimized design of the reactive distillation column; the segmented design of the reactive distillation column reduces the length of a single column, reduces the height of the device frame, and reduces investment costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model; The components are as follows: 1. First reactive distillation column; 2. Second reactive distillation column; 3. First condenser; 4. First reaction section; 5. First separation section; 6. Chlorosilane feed pipe; 7. First column top discharge pipe; 8. First column bottom discharge pipe; 9. First column bottom reflux pipe; 10. Tetrachlorosilane discharge pipe; 11. First reboiler; 12. Second column bottom reflux pipe; 13. Second condenser; 14. Second separation section; 15. Second reaction section; 16. Third separation section; 17. Methylsilane discharge pipe; 18. Side discharge pipe; 19. Side reflux pipe. 20. Second reboiler reef outlet pipe; 21. Third condenser; 22. Connecting pipe; 23. Third reboiler refluxing pipe; 24. Second reboiler; 25. Fourth reboiler refluxing pipe; 26. First refrigerant feed pipe; 27. First refrigerant discharge pipe; 28. First heat medium feed pipe; 29. ​​First heat medium discharge pipe; 30. Second refrigerant feed pipe; 31. Second refrigerant discharge pipe; 32. Second heat medium feed pipe; 33. Second heat medium discharge pipe; 34. Third refrigerant feed pipe; 35. Third refrigerant discharge pipe; 36. Transfer pump. Detailed Implementation The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0021] Example 1 like Figure 1 As shown, a reactive distillation apparatus for the disproportionation of chlorosilanes includes a first reactive distillation column 1 and a second reactive distillation column 2. The first reactive distillation column 1 is provided with a first condenser 3, a first reaction section 4, and a first separation section 5 arranged sequentially from top to bottom. The first reactive distillation column 1 is equipped with a chlorosilane feed pipe 6, a first top outlet pipe 7, and a first bottom outlet pipe 8. The first bottom outlet pipe 8 is equipped with a first bottom reflux pipe 9 and a tetrachlorosilane outlet pipe 10. The first bottom reflux pipe 9 is equipped with a first reboiler 11, which is connected to the first reactive distillation column 1 via a second bottom reflux pipe 12. The first top outlet pipe 7 is connected to the second reactive distillation column 2. The second reactive distillation column 2 is provided with a second condenser 13, a second separation section 14, a second reaction section 15 and a third separation section 16 arranged sequentially from top to bottom. The second reactive distillation column 2 is provided with a silane discharge pipe 17, a side discharge pipe 18, a side reflux pipe 19 and a second column bottom discharge pipe 20. A third condenser 21 is arranged between the side discharge pipe 18 and the side reflux pipe 19. The second column bottom discharge pipe 20 is connected to a connecting pipe 22 and a third column bottom reflux pipe 23. A second reboiler 24 is arranged on the third column bottom reflux pipe 23. The second reboiler 24 is connected to the second reactive distillation column 2 through a fourth column bottom reflux pipe 25. The connecting pipe 22 is connected to the first reactive distillation column 1.

[0022] Example 2 like Figure 1As shown, a reactive distillation apparatus for the disproportionation of chlorosilanes includes a first reactive distillation column 1 and a second reactive distillation column 2. The first reactive distillation column 1 is provided with a first condenser 3, a first reaction section 4, and a first separation section 5 arranged sequentially from top to bottom. The first reactive distillation column 1 is equipped with a chlorosilane feed pipe 6, a first top outlet pipe 7, and a first bottom outlet pipe 8. The first bottom outlet pipe 8 is equipped with a first bottom reflux pipe 9 and a tetrachlorosilane outlet pipe 10. The first bottom reflux pipe 9 is equipped with a first reboiler 11, which is connected to the first reactive distillation column 1 via a second bottom reflux pipe 12. The first top outlet pipe 7 is connected to the second reactive distillation column 2. The second reactive distillation column 2 is provided with a second condenser 13, a second separation section 14, a second reaction section 15 and a third separation section 16 arranged sequentially from top to bottom. The second reactive distillation column 2 is provided with a silane discharge pipe 17, a side discharge pipe 18, a side reflux pipe 19 and a second column bottom discharge pipe 20. A third condenser 21 is arranged between the side discharge pipe 18 and the side reflux pipe 19. The second column bottom discharge pipe 20 is connected to a connecting pipe 22 and a third column bottom reflux pipe 23. A second reboiler 24 is arranged on the third column bottom reflux pipe 23. The second reboiler 24 is connected to the second reactive distillation column 2 through a fourth column bottom reflux pipe 25. The connecting pipe 22 is connected to the first reactive distillation column 1.

[0023] The connection between the chlorosilane feed pipe 6 and the first reactive distillation column 1, and the connection between the connecting pipe 22 and the first reactive distillation column 1, are both located between the first reaction section 4 and the first condenser 3.

[0024] The connection between the first top discharge pipe 7 and the second reactive distillation column 2 is located on the side wall of the second reactive distillation column 2 at the lower end of the third separation section 16.

[0025] The connection between the side discharge pipe 18 and the second reactive distillation column 2 and the connection between the side reflux pipe 19 and the second reactive distillation column 2 are both located between the second separation section 14 and the second reaction section 15.

[0026] The first condenser 3 is equipped with a first refrigerant inlet pipe 26 and a first refrigerant outlet pipe 27. The first refrigerant is a room temperature refrigerant, such as circulating water.

[0027] The first reboiler 11 is equipped with a first heat medium inlet pipe 28 and a first heat medium outlet pipe 29. The first heat medium is a high-temperature heat medium, such as steam or high-temperature water.

[0028] The second condenser 13 is equipped with a second refrigerant inlet pipe 30 and a second refrigerant outlet pipe 31. The second refrigerant is an ultra-low temperature refrigerant, such as Freon, ethylene glycol aqueous solution, or dichloromethane.

[0029] The second reboiler 24 is equipped with a second heat medium inlet pipe 32 and a second heat medium outlet pipe 33. The second heat medium is a high-temperature heat medium, such as steam or high-temperature water.

[0030] The third condenser 21 is equipped with a third refrigerant inlet pipe 34 and a third refrigerant outlet pipe 35. The third refrigerant is a low-temperature refrigerant, such as low-temperature water or Freon.

[0031] The connecting pipe 22 is equipped with a transfer pump 36.

[0032] The first separation section 5, the second separation section 14, and the third separation section 16 all use packing material; the first reaction section 4 and the second reaction section 15 both use packing material, with a catalyst added to the packing material; the first condenser 3, the first reboiler 11, the second condenser 13, the third condenser 21, the second reboiler 24, and the transfer pump 36 are all existing technologies and will not be described in detail here. Distributors are installed on the connecting pipe 22 inserted into the first reactive distillation column 1 and the side reflux pipe 19 inserted into the second reactive distillation column 2, and the distributors have multiple liquid outlets.

[0033] Compared with the prior art, this utility model has the following advantages and beneficial effects: I. This utility model provides a reactive distillation apparatus for the disproportionation of chlorosilanes. The first separation section 5 of the first reactive distillation column 1 separates silicon tetrachloride, forcibly moving unreacted materials upwards to enhance the reaction. The first cooler of the first reactive distillation column 1 forces heavy components downwards to participate in the reaction. The second reboiler 24 of the second reactive distillation column 2 forces the target product dichlorosilane from the first reactive distillation column 1 upwards to react in the second reactive distillation column 2. The third separation section 16 of the second reactive distillation column 2 also enhances component separation, moving trichlorosilane downwards and forcing dichlorosilane and monochlorosilane upwards to react. The third condenser 21 of the second reactive distillation column 2 also forces component separation, condensing the reboiling point chlorosilane into a liquid phase for forced reaction. The second separation section 14 of the second reactive distillation column 2 separates heavy components for further reaction. The second condenser 13 of the second reactive distillation column 2 achieves forced reflux. This utility model simplifies the process, simplifies the equipment, improves the reaction conversion rate, and reduces energy consumption.

[0034] II. The present invention provides a reactive distillation device for disproportionation of chlorosilane. Under the separation action of the chlorosilane added through the chlorosilane feed pipe 6 and the third separation section 16 in the second reactive distillation column 2, the trichlorosilane from the first reactive distillation column 1 is added between the first reaction section 4 and the first condenser 3, so that the disproportionation reaction (mainly reaction 1 occurs, and reaction 2 occurs in a small amount) is more effective.

[0035] III. The reactive distillation equipment for disproportionation of chlorosilane provided by this utility model improves the overall conversion rate and reduces the overall energy consumption level through the optimized design of the reactive distillation column; the segmented design of the reactive distillation column reduces the length of a single column, reduces the height of the device frame, and reduces investment costs.

[0036] The working principle of this invention is as follows: chlorosilane is added to the first reactive distillation column 1 through the chlorosilane feed pipe 6. The material enters the first reaction section 4, where a disproportionation reaction occurs under the action of a catalyst (mainly reaction 1, with a small amount of reaction 2). At the bottom of the catalyst, the reacted material is separated in the first separation section 5. The heavy component, silicon tetrachloride, is collected from the bottom of the column, while the unreacted trichlorosilane enters the first reaction section 4 to continue reacting. The first condenser 3 at the top of the first reactive distillation column 1 condenses the trichlorosilane and silicon tetrachloride flowing from the top of the first reaction section 4 into a liquid phase, which flows downwards under gravity. Meanwhile, the low-boiling-point materials such as dichlorosilane and monochlorosilane generated by the reaction enter the second reactive distillation column 2 in gaseous form. In the second reactive distillation column 2, under the separation action of the third separation section 16, trichlorosilane from the first reactive distillation column 1 is separated to the bottom of the column and transported back to the first reactive distillation column 1 through the connecting pipe 22. Meanwhile, the light-boiling-point dichlorosilane and monochlorosilane enter the second reaction section 15 of the second reactive distillation column 2 in the form of gas and react in the second reaction section 15. After the reaction, under the cooling action of the second condenser 13, the unreacted dichlorosilane and monochlorosilane and other heavy components flow towards the second reaction section 15 by gravity to enhance the reaction. The uncondensed silane, monochlorosilane and a small amount of dichlorosilane enter the second separation section 14 for separation. In the second separation section 14, monochlorosilane and a small amount of dichlorosilane move downward and silane moves upward. In the second separation section 14, the unseparated silane, monochlorosilane, and trace amounts of dichlorosilane are refluxed by the second condenser 13, while the uncondensed silane is extracted from the tower body in the gas phase.

[0037] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A reactive distillation apparatus for the disproportionation of chlorosilanes, characterized in that: The system includes a first reactive distillation column (1) and a second reactive distillation column (2). The first reactive distillation column (1) is equipped with a first condenser (3), a first reaction section (4), and a first separation section (5) arranged sequentially from top to bottom. The first reactive distillation column (1) is equipped with a chlorosilane feed pipe (6), a first top outlet pipe (7), and a first bottom outlet pipe (8). The first bottom outlet pipe (8) is equipped with a first bottom reflux pipe (9) and a tetrachlorosilane outlet pipe (10). The first bottom reflux pipe (9) is equipped with a first reboiler (11), which is connected to the first reactive distillation column (1) via a second bottom reflux pipe (12). The first top outlet pipe (7) is connected to the second reactive distillation column (2). The second condenser (13), the second separation section (14), the second reaction section (15) and the third separation section (16) are arranged sequentially from top to bottom. The second reactive distillation column (2) is provided with a silane discharge pipe (17), a side discharge pipe (18), a side reflux pipe (19) and a second column bottom discharge pipe (20). A third condenser (21) is arranged between the side discharge pipe (18) and the side reflux pipe (19). The second column bottom discharge pipe (20) is connected to the connecting pipe (22) and the third column bottom reflux pipe (23). A second reboiler (24) is arranged on the third column bottom reflux pipe (23). The second reboiler (24) is connected to the second reactive distillation column (2) through the fourth column bottom reflux pipe (25). The connecting pipe (22) is connected to the first reactive distillation column (1).

2. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The connection between the chlorosilane feed pipe (6) and the first reactive distillation column (1), and the connection between the connecting pipe (22) and the first reactive distillation column (1), are both located between the first reaction section (4) and the first condenser (3).

3. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The connection between the first top discharge pipe (7) and the second reactive distillation column (2) is located on the side wall of the second reactive distillation column (2) at the lower end of the third separation section (16).

4. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The connection between the side discharge pipe (18) and the second reactive distillation column (2) and the connection between the side reflux pipe (19) and the second reactive distillation column (2) are both located between the second separation section (14) and the second reaction section (15).

5. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The first condenser (3) is provided with a first refrigerant inlet pipe (26) and a first refrigerant outlet pipe (27).

6. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The first reboiler (11) is provided with a first heat medium feed pipe (28) and a first heat medium discharge pipe (29).

7. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The second condenser (13) is provided with a second refrigerant inlet pipe (30) and a second refrigerant outlet pipe (31).

8. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The second reboiler (24) is provided with a second heat medium feed pipe (32) and a second heat medium discharge pipe (33).

9. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: The third condenser (21) is provided with a third refrigerant inlet pipe (34) and a third refrigerant outlet pipe (35).

10. The reactive distillation apparatus for disproportionation of chlorosilanes according to claim 1, characterized in that: A transfer pump (36) is installed on the connecting pipe (22).

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