Device for preparing silane through partition reactive distillation

Abstract

The utility model relates to a device for preparing silane through partition plate reactive distillation, which comprises a partition plate reactive distillation tower body, a reboiler, a condenser, a first fractional condenser, a second fractional condenser, a side extraction pump and a partition plate arranged in the partition plate reactive distillation tower. The partition plate reaction rectifying tower is divided into a public rectifying section, a partition plate reaction upper section, a partition plate reaction lower section, a partition plate separation section and a public stripping section by the partition plates; compared with a production device adopting a combination mode of a reactive distillation tower and a separation tower in the existing silane preparation technology, the integrated structure is arranged, and the reactive distillation tower and the separation tower are optimized into one partition reactive distillation tower, so that the equipment investment is saved by more than 20%, and the energy consumption of the device is also reduced by 10-30%.

Description

Technical Field

[0001] The utility model relates to the chemical industry field, in particular to a device for preparing silane by partition reaction distillation. Background Art

[0002] Silane, also known as monosilane or silico hydride, is a colorless and extremely flammable gas with the chemical formula SiH 4 ; It is easy to purify and can be finely controlled, and is known as "flowing pure silicon". It is the core raw material for preparing high-purity crystalline silicon by the silane method, and is also an important electronic special gas that cannot be replaced by other silicon sources. It is widely used in fields such as TFT / LCD, crystalline silicon solar cells, semiconductors, and emerging silicon-carbon anodes and advanced ceramics. Silane is almost used in the entire new energy, semiconductor, and new material industries; The main preparation methods of silane include the magnesium silicide method, the sodium aluminum hydride method, and the chlorosilane disproportionation method; The main preparation methods of silane are the magnesium silicide method, the sodium aluminum hydride method, and the chlorosilane disproportionation method. Among them, the chlorosilane disproportionation method is to carry out a hydrogenation reaction on silicon tetrachloride to synthesize trichlorosilane, and then trichlorosilane undergoes three-step reversible disproportionation reactions to generate silane products and by-product silicon tetrachloride, and the silicon tetrachloride returns to the hydrogenation process; The whole system is in a closed-loop cycle, with almost no external emissions, high atom utilization rate, and is environmentally friendly, very suitable for industrial production, and has become the main method for silane preparation.

[0003] The chlorosilane disproportionation method was developed by Union Carbide Corporation (UCC) of the United States and proposed in patent US4340574. This process combines multi-step disproportionation reactions through two-stage fixed beds with rectification and purification to prepare silane. Due to the limitation of the reaction equilibrium, the single-pass yield of silane is less than 8 mol.%, a large amount of materials need to be recycled, the process flow is long, the production efficiency is low, and the energy consumption and investment are large.

[0004] The patent with the application number CN103172071B discloses a device and method for preparing high-purity silane by trichlorosilane disproportionation reaction distillation, which is composed of a reaction distillation process, a silicon tetrachloride absorption process, a fixed-bed adsorption process, and a product canning process connected; The process flow is complex, and the silane after absorption still contains uncondensed chlorosilane, which affects the subsequent adsorption process and the product purity is low. Content of the Utility Model

[0005] In order to overcome the problems of relatively large equipment investment and high operating costs existing in the production devices adopting the combined mode of a reactive distillation column and a separation column in the existing silane preparation technology, the technical solution of the present utility model is: a device for preparing silane by partition reactive distillation, including a partition reactive distillation column body and a partition plate arranged in the partition reactive distillation column. The partition plate is fixedly connected to the inner wall of the partition reactive distillation column. The partition plate divides the partition reactive distillation column into a common rectifying section, an upper partition reaction section, a lower partition reaction section, a partition separation section and a common stripping section. The common rectifying section is located above the partition plate. The upper partition reaction section is located in the upper half part on one side of the partition plate. The lower partition reaction section is located in the lower half part on one side of the partition plate and is on the same side as the upper partition reaction section. The partition separation section is located on the other side of the partition plate. The common stripping section is located below the partition plate. Preferably, by setting an integrated structure, the reactive distillation column and the separation column device are optimized into a single partition reactive distillation column, saving more than 20% of the equipment investment and reducing the energy consumption of the device by 10 - 30%.

[0006] Preferably, a liquid collection and redistribution device is arranged at the bottom end of the common rectifying section of the partition reactive distillation column. The liquid phase outlet of the liquid collection and redistribution device is communicated with the liquid phase reflux port at the top end of the partition separation section, and the liquid phase outlet of the liquid collection and redistribution device is communicated with the liquid phase reflux port at the top end of the upper partition reaction section. During use, the liquid collection and redistribution device distributes the liquid flowing out of the common rectifying section to both sides of the partition according to a certain ratio.

[0007] Preferably, heads are arranged at both the top and the bottom of the upper partition reaction section of the partition reactive distillation column. A circulating material inlet and a liquid phase reflux port are arranged at the top end of the upper partition reaction section. It further includes a first partial condenser. The gas phase inlet of the first partial condenser is communicated with the gas phase outlet at the top end of the upper partition reaction section. The liquid phase outlet of the first partial condenser is communicated with the liquid phase reflux port at the top end of the upper partition reaction section. The gas phase outlet of the first partial condenser is communicated with the gas phase inlet at the bottom end of the common rectifying section.

[0008] Preferably, a head is arranged at the top of the lower partition reaction section of the partition reactive distillation column. A feed inlet and a liquid phase reflux port are arranged at the top end of the lower partition reaction section. It further includes a second partial condenser. The gas phase inlet of the second partial condenser is communicated with the gas phase outlet at the top end of the lower partition reaction section. The liquid phase outlet of the second partial condenser is communicated with the liquid phase reflux port at the top end of the lower partition reaction section. The gas phase outlet of the second partial condenser is communicated with the gas phase inlet at the bottom end of the upper partition reaction section.

[0009] Preferably, a gas phase outlet and a liquid phase reflux port are arranged at the top end of the partition reactive distillation column. It further includes a condenser. The gas phase inlet of the condenser is communicated with the gas phase outlet at the top end of the partition reactive distillation column. The liquid phase outlet of the condenser is communicated with the liquid phase reflux port at the top end of the partition reactive distillation column. The gas phase outlet of the condenser is communicated with the silane discharge pipeline.

[0010] Preferably, two liquid-phase outlets are provided at the bottom end of the partitioned reactive distillation column, a gas-phase inlet is provided at the column still of the partitioned reactive distillation column, and a reboiler is further included. The liquid-phase inlet of the reboiler is communicated with one of the liquid-phase outlets at the bottom end of the partitioned reactive distillation column, the gas-phase outlet of the reboiler is communicated with the gas-phase inlet at the column still of the partitioned reactive distillation column, and the other liquid-phase outlet at the bottom end of the partitioned reactive distillation column is communicated with the silicon tetrachloride discharge pipeline.

[0011] Preferably, a liquid-phase reflux port is provided at the top end of the partition separation section of the partitioned reactive distillation column, a side draw port is provided in the middle and lower part of the partition separation section, the inlet of the side draw pump is communicated with the side draw port of the partition separation section, and the outlet of the side draw pump is communicated with the circulating material inlet at the top end of the upper section of the partitioned reactive distillation column.

[0012] Preferably, structured catalysts with a height of 2 - 10 m are filled inside the upper section of the partitioned reaction; structured catalysts with a height of 2 - 10 m are filled inside the lower section of the partitioned reaction; structured packing with a theoretical plate number of 3 - 10, trays, or separation elements composed of a combination of both are filled inside the common rectification section; structured packing with a theoretical plate number of 25 - 40, trays, or separation elements composed of a combination of both are filled inside the partition separation section; structured packing with a theoretical plate number of 10 - 25, trays, or separation elements composed of a combination of both are filled inside the common stripping section.

[0013] Preferably, during operation, trichlorosilane or dichlorosilane or a mixture of both is fed from the feed port at the top end of the lower section of the partitioned reaction of the partitioned reactive distillation column. The gas phases rising on both sides of the partition converge in the common rectification section above the partition, and the liquid phases descending on both sides of the partition converge in the common stripping section at the bottom of the partition. The liquid phase at the bottom end of the common rectification section is distributed to both sides of the partition in a certain proportion; silane with a purity greater than 99.99 wt% is obtained from the top of the column, silicon tetrachloride with a purity greater than 99.9 wt% is obtained from the column still, and a mixture such as dichlorosilane and monochlorotrisilane is drawn from the middle and lower part of the partition separation section, pressurized by the side draw pump, and then returned to the circulating material feed port at the top end of the upper section of the partitioned reaction.

[0014] The beneficial effects of the present utility model are as follows:

[0015] Compared with the production device adopting the combined mode of a reactive distillation column and a separation column in the existing silane preparation technology, by setting an integrated structure, the reactive distillation column and the separation column device are optimized into a single partitioned reactive distillation column, saving more than 20% of the equipment investment and reducing the device energy consumption by 10 - 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a three-dimensional structural schematic diagram of the device for preparing silane by partitioned reactive distillation of the present utility model;

[0017] Figure 2The figure shows a schematic cross-sectional structure diagram of the device for preparing silane by partition reaction distillation of the present utility model;

[0018] Figure 3 The figure shows a schematic structural principle diagram of the device for preparing silane by partition reaction distillation of the present utility model;

[0019] Figure 4 The figure shows a schematic side three-dimensional structure diagram of the device for preparing silane by partition reaction distillation of the present utility model;

[0020] Explanation of reference numerals: 1. Reaction distillation column body; 2. Partition plate; 3. Common rectifying section; 4. Upper partition reaction section; 5. Lower partition reaction section; 6. Partition separation section; 7. Common stripping section; 8. Liquid collection and redistribution device; 9. First partial condenser; 10. Second partial condenser; 11. Condenser; 12. Silane discharge pipeline; 13. Reboiler; 14. Silicon tetrachloride discharge pipeline; 15. Side draw pump. Specific embodiments

[0021] The present utility model will be further described below with reference to the drawings and embodiments.

[0022] Please refer to Figure 1-2 , the present utility model provides an embodiment: a device for preparing silane by partition reaction distillation, including a reaction distillation column body 1 of the partition reaction distillation and a partition plate 2 arranged inside the partition reaction distillation column. The partition plate 2 is fixedly connected to the inner wall of the reaction distillation column. The partition plate 2 divides the partition reaction distillation column into a common rectifying section 3, an upper partition reaction section 4, a lower partition reaction section 5, a partition separation section 6 and a common stripping section 7. The common rectifying section 3 is located above the partition plate 2. The upper partition reaction section 4 is located in the upper half of one side of the partition plate 2. The lower partition reaction section 5 is located in the lower half of one side of the partition plate 2 and is on the same side as the upper partition reaction section 4. The partition separation section 6 is located on the other side of the partition plate 2. The common stripping section 7 is located below the partition plate 2.

[0023] Please refer to Figure 3-4, in this embodiment, a liquid collection and redistribution device 8 is provided at the bottom of the common rectifying section 3 of the partitioned reactive distillation column. The liquid phase outlet of the liquid collection and redistribution device 8 is communicated with the liquid phase reflux port at the top of the partitioned separation section 6, and the liquid phase outlet of the liquid collection and redistribution device 8 is communicated with the liquid phase reflux port at the top of the upper partitioned reaction section 4. During use, the liquid collection and redistribution device 8 distributes the liquid flowing out of the common rectifying section 3 to both sides of the partition according to a certain ratio. The top and bottom of the upper partitioned reaction section 4 of the partitioned reactive distillation column are both provided with heads. The top of the upper partitioned reaction section 4 is provided with a circulating material inlet and a liquid phase reflux port. A first partial condenser 9 is further included. The gas phase inlet of the first partial condenser 9 is communicated with the gas phase outlet at the top of the upper partitioned reaction section 4, the liquid phase outlet of the first partial condenser 9 is communicated with the liquid phase reflux port at the top of the upper partitioned reaction section 4, and the gas phase outlet of the first partial condenser 9 is communicated with the gas phase inlet at the bottom of the common rectifying section 3. The top of the lower partitioned reaction section 5 of the partitioned reactive distillation column is provided with a head. The top of the lower partitioned reaction section 5 is provided with a feed inlet and a liquid phase reflux port. A second partial condenser 10 is further included. The gas phase inlet of the second partial condenser 10 is communicated with the gas phase outlet at the top of the lower partitioned reaction section 5, the liquid phase outlet of the second partial condenser 10 is communicated with the liquid phase reflux port at the top of the lower partitioned reaction section 5, and the gas phase outlet of the second partial condenser 10 is communicated with the gas phase inlet at the bottom of the upper partitioned reaction section 4.

[0024] The top of the partitioned reactive distillation column 1 is provided with a gas phase outlet and a liquid phase reflux port. A condenser 11 is further included. The gas phase inlet of the condenser 11 is communicated with the gas phase outlet at the top of the partitioned reactive distillation column 1, the liquid phase outlet of the condenser 11 is communicated with the liquid phase reflux port at the top of the partitioned reactive distillation column 1, and the gas phase outlet of the condenser 11 is communicated with the silane discharge pipeline 12. The bottom of the partitioned reactive distillation column 1 is provided with two liquid phase outlets. The bottom of the column of the partitioned reactive distillation column 1 is provided with a gas phase inlet. A reboiler 13 is further included. The liquid phase inlet of the reboiler 13 is communicated with one of the liquid phase outlets at the bottom of the partitioned reactive distillation column 1, the gas phase outlet of the reboiler 13 is communicated with the gas phase inlet at the bottom of the column of the partitioned reactive distillation column 1, and the other liquid phase outlet at the bottom of the partitioned reactive distillation column 1 is communicated with the silicon tetrachloride discharge pipeline 14. The top of the partitioned separation section 6 of the partitioned reactive distillation column is provided with a liquid phase reflux port. A side draw port is provided in the middle and lower part of the partitioned separation section 6. The inlet of the side draw pump 15 is communicated with the side draw port of the partitioned separation section 6, and the outlet of the side draw pump 15 is communicated with the circulating material inlet at the top of the upper partitioned reaction section 4.

[0025] The upper part of the partition reaction section 4 is filled with a structured catalyst with a height of 2 - 10 m, and the lower part of the partition reaction section 5 is filled with a structured catalyst with a height of 2 - 10 m; the common rectifying section 3 is filled with a structured packing, a tray, or a separation element composed of a combination of both with a theoretical plate number of 3 - 10, the partition separation section 6 is filled with a structured packing, a tray, or a separation element composed of a combination of both with a theoretical plate number of 25 - 40, and the common stripping section 7 is filled with a structured packing, a tray, or a separation element composed of a combination of both with a theoretical plate number of 10 - 25.

[0026] Among them, the first partial condenser 9 is a condenser 9 that uses a refrigerant with a temperature not higher than 15°C as the condensing medium; the second partial condenser 10 is a condenser 10 that uses circulating water as the condensing medium; the condenser 11 is a condenser 11 that uses a refrigerant with a temperature not higher than -90°C as the condensing medium; the reboiler 13 is a reboiler 13 that uses a high-grade heat source such as low-pressure steam or heat-conducting oil; the top pressure of the partition reaction distillation column is 0.2 - 0.4 MPaG, the top temperature is -70 - 90°C, and the top reflux ratio is 1.0 - 10:1; the material temperature controlled by the first partial condenser 9 is 10 - 40°C; the material temperature controlled by the second partial condenser 10 is 40 - 70°C.

[0027] Example 1

[0028] This example is illustrated by the calculation of a high-purity silane preparation project with a trichlorosilane treatment capacity of 3200 kg / h.

[0029] Trichlorosilane with a mass fraction of 100% and a temperature of 80°C enters from the raw material inlet at the top of the lower part of the partition reaction section 5 with a mass flow rate of 3200 kg / h. Using a suitable tower structure and optimized operating conditions, a silane product with a mass fraction greater than 99.99% and a mass flow rate of 189.5 kg / h is obtained from the top of the tower; silicon tetrachloride with a mass fraction greater than 99.9% and a mass flow rate of 3010.5 kg / h is obtained from the bottom of the tower. The calculation results are as follows:

[0030] The energy consumption of the first partial condenser 9 is -278.5 kw, the energy consumption of the second partial condenser 10 is -407.6 kw, the energy consumption of the condenser 11 is -71.7 kw, and the total cooling load is -757.8 kw;

[0031] The heating amount of the reboiler 13 is 847.6 kw.

[0032] The energy-saving ratio of the heat load is 25.12% and the energy-saving ratio of the cooling load is 27.28% compared with the existing technology.

[0033] Example 2

[0034] This example is illustrated by the calculation of a high-purity silane preparation project with a dichlorosilane treatment capacity of 4110 kg / h.

[0035] Silicon dichloride dihydride with a mass fraction of 100% and a temperature of 75 °C enters from the raw material feed port at the top of the lower part 5 of the partition reaction section at a mass flow rate of 4110 kg / h. By using a suitable tower structure and optimizing the operating conditions, a silane product with a mass fraction greater than 99.99% and a mass flow rate of 653 kg / h is obtained from the top of the tower; silicon tetrachloride with a mass fraction greater than 99.9% and a mass flow rate of 3457 kg / h is obtained from the bottom of the tower. The calculation results are as follows:

[0036] The energy consumption of the first partial condenser 9 is -625.4 kw, the energy consumption of the second partial condenser 10 is -66.6 kw, the energy consumption of the condenser 11 is -136.7 kw, and the total cooling load is -828.7 kw.

[0037] The heating amount of the reboiler 13 is 972.9 kw.

[0038] The energy-saving ratio of the heat load is 12.23% and the energy-saving ratio of the cooling load is 14.13% compared with the scheme in the prior art.

[0039] During operation, trichlorosilane or silicon dichloride dihydride or a mixture of the two is fed from the top of the lower part 5 of the partition reaction section of the partition reaction distillation column. The gas phases rising on both sides of the partition converge in the common rectifying section 3 above the partition, and the liquid phases descending on both sides of the partition converge in the common stripping section 7 at the bottom of the partition. The liquid phase at the bottom of the common rectifying section 3 is distributed to both sides of the partition in a certain proportion; silane with a purity greater than 99.99 wt% is obtained from the top of the tower, silicon tetrachloride with a purity greater than 99.9 wt% is obtained from the bottom of the tower, and a mixture of silicon dichloride dihydride and trichlorosilane hydrogen is taken out from the middle and lower part of the partition separation section 6, pressurized by the side draw pump 15, and returned to the circulating material feed port at the top of the upper part 4 of the partition reaction section.

[0040] Through the above steps, by using an integrated structure, the reaction distillation column and the separation tower device are optimized into a partition reaction distillation column, saving more than 20% of the equipment investment and reducing the device energy consumption by 10 - 30%.

[0041] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those skilled in the art.

Claims

1. A device for preparing silane by baffle plate reaction distillation, comprising a baffle plate reaction distillation tower body (1); characterized in that: The invention also comprises a partition plate (2) arranged in the partition plate reaction distillation tower, the partition plate (2) is fixedly connected to the inner wall of the partition plate reaction distillation tower, and the partition plate (2) divides the partition plate reaction distillation tower into a common distillation section (3), a partition plate reaction upper section (4), a partition plate reaction lower section (5), a partition plate separation section (6) and a common stripping section (7); the common distillation section (3) is located above the partition plate (2), the partition plate reaction upper section (4) is located in the upper half of one side of the partition plate (2), the partition plate reaction lower section (5) is located in the lower half of one side of the partition plate (2) and on the same side as the partition plate reaction upper section (4), the partition plate separation section (6) is located on the other side of the partition plate (2), and the common stripping section (7) is located below the partition plate (2).

2. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: It also includes a liquid collecting redistributor (8), which is arranged at the bottom end of the common distillation section (3) of the partition reaction distillation tower, the liquid phase outlet of the liquid collecting redistributor (8) is connected to the liquid phase reflux port at the top of the partition separation section (6), and the liquid phase outlet of the liquid collecting redistributor (8) is connected to the liquid phase reflux port at the top of the partition reaction upper section (4).

3. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: The top and bottom of the partition plate reaction upper section (4) are both provided with heads, the top of the partition plate reaction upper section (4) is provided with a circulating material inlet and a liquid phase reflux port, and also includes a first condenser (9), the gas phase inlet of the first condenser (9) is connected to the gas phase outlet at the top of the partition plate reaction upper section (4), the liquid phase outlet of the first condenser (9) is connected to the liquid phase reflux port at the top of the partition plate reaction upper section (4), and the gas phase outlet of the first condenser (9) is connected to the gas phase inlet at the bottom of the common distillation section (3).

4. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: A head is provided at the top of the baffle reaction lower section (5), a feed port and a liquid phase reflux port are provided at the top of the baffle reaction lower section (5), and the second condenser (10) is also included, the gas phase inlet of the second condenser (10) is connected to the gas phase outlet at the top of the baffle reaction lower section (5), the liquid phase outlet of the second condenser (10) is connected to the liquid phase reflux port at the top of the baffle reaction lower section (5), and the gas phase outlet of the second condenser (10) is connected to the gas phase inlet at the bottom of the baffle reaction upper section (4).

5. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: The top of the baffle reaction distillation tower is provided with a gas phase outlet and a liquid phase reflux port, and also includes a condenser (11), the gas phase inlet of the condenser (11) is connected to the gas phase outlet at the top of the baffle reaction distillation tower, the liquid phase outlet of the condenser (11) is connected to the liquid phase reflux port at the top of the baffle reaction distillation tower, and the gas phase outlet of the condenser (11) is connected to the silane discharge pipeline (12).

6. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: The bottom end of the baffle reaction distillation tower is provided with two liquid phase outlets, the tower kettle of the baffle reaction distillation tower is provided with a gas phase inlet, and also includes a reboiler (13), the liquid phase inlet of the reboiler (13) is connected to one of the liquid phase outlets at the bottom end of the baffle reaction distillation tower, the gas phase outlet of the reboiler (13) is connected to the gas phase inlet of the tower kettle of the baffle reaction distillation tower, and the other liquid phase outlet at the bottom end of the baffle reaction distillation tower is connected to the silicon tetrachloride discharge pipeline (14).

7. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: A liquid phase reflux port is provided at the top of the partition separation section (6), a material side sampling port is provided at the middle and lower part of the partition separation section (6), an inlet of the side sampling pump (15) is connected to the material side sampling port of the partition separation section (6), and an outlet of the side sampling pump (15) is connected to the circulating material inlet at the top of the partition reaction upper section (4).

8. The device for preparing silane by baffle reactive distillation according to claim 1, characterized in that: The interior of the partition plate reaction upper section (4) is filled with a structured catalyst with a height of 2-10m, and the interior of the partition plate reaction lower section (5) is filled with a structured catalyst with a height of 2-10m; the interior of the common distillation section (3) is filled with structured packing, tower trays or separation elements of a composite of the two with a theoretical plate number of 3-10, the interior of the partition plate separation section (6) is filled with structured packing, tower trays or separation elements of a composite of the two with a theoretical plate number of 25-40, and the interior of the common stripping section (7) is filled with structured packing, tower trays or separation elements of a composite of the two with a theoretical plate number of 10-25.

Images