A silane reactive rectification column for increasing productivity and a working method thereof

Abstract

This invention discloses a silane reactive distillation column for improving production capacity and its operating method. The distillation column has an upper section for rectification, a middle section for reaction, and a lower section for stripping. A condenser is installed at the top of the column, and a reboiler is installed at the bottom. The reaction section has multiple segments, each equipped with a distributor and a catalyst. Adjacent sections of the multiple reaction segments are equipped with packing sections. The bottom of each packing section has an oil collection tank and an overflow device, both connected to the distributor in the lower reaction section. This invention, while ensuring normal reaction and separation, adds an oil collection tank and an overflow device at the bottom of the packing section to concentrate and separate some by-products and products. When by-products are removed in a timely manner, the amount of by-products in the reaction section decreases, improving the forward reaction process, increasing reaction efficiency, and yielding more product.

Description

Technical Field

[0001] This invention relates to a silane reactive distillation column for increasing production capacity and its operating method, belonging to the field of distillation column technology. Background Technology

[0002] Silicon-based materials are the most important foundational materials for the electronics and information industry and the solar photovoltaic power generation industry. Currently, polycrystalline silicon, used in solar photovoltaic power generation, is a highly efficient, environmentally friendly, and clean new energy technology. There are many production processes for polycrystalline silicon, but the main processes that have been industrialized on a large scale are the modified Siemens process and the silane thermal decomposition process. The silane thermal decomposition process has advantages over the modified Siemens process in producing polycrystalline silicon, including a simpler process, lower decomposition temperature, and lower energy consumption. Therefore, the silane method is increasingly becoming the main method for producing polycrystalline silicon. Since silane is the most important reactant, its production capacity directly affects the yield of polycrystalline silicon products. Currently, silane is mainly produced through reactive distillation. How to improve the production capacity and reaction efficiency of silane in reactive distillation is a problem that needs to be solved. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a silane reactive distillation column and its working method for improving production capacity, thereby increasing the production capacity and reaction efficiency of silane in the reactive distillation process.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0005] In a first aspect, the present invention provides a silane reactive distillation column for improving production capacity. The distillation column has an upper section for rectification, a middle section for reaction, and a lower section for stripping. A condenser is provided at the top of the distillation column, with a condenser pipe connected to the top of the column at one end and a reflux pipe at the other end returning to the rectification section. An outlet pipe at the other end of the condenser connects to the outside of the distillation column. A reboiler is provided at the bottom of the distillation column, with its inlet pipe connected to the bottom of the stripping section and its outlet pipe returning to the stripping section. The reaction section has multiple segments, each containing a distributor and a catalyst. Adjacent portions of the multiple reaction segments are provided with packing sections, and the bottom of each packing section has an oil collection tank and an overflow device. Both the oil collection tank and the overflow device are connected to the distributor in the lower reaction section.

[0006] Furthermore, the lower part of the oil collection tank is provided with a by-product extraction pipeline, and the oil collection tank is connected to the distributor in the lower reaction section through the by-product extraction pipeline.

[0007] Furthermore, the overflow device is installed at a set height inside the oil collection tank. The top of the overflow device is open, and the bottom is connected to an overflow pipeline. The overflow device is connected to the distributor in the lower reaction section through the overflow pipeline.

[0008] Furthermore, a flow meter is installed on the overflow pipeline, and an insulation layer is provided on the outside of the overflow pipeline.

[0009] Furthermore, the oil collection tank is equipped with a tuning fork switch, a regulating valve, and a thermometer.

[0010] Furthermore, the packing section is provided with double-layered packing sheets, and a catalyst is provided between the double-layered packing sheets.

[0011] Furthermore, the height of the oil collection tank is 800-1200mm below the packing section.

[0012] Furthermore, the height of the inlet of the overflow device is 200-400mm inside the oil collector.

[0013] Furthermore, the reaction section is divided into three segments.

[0014] In a second aspect, the present invention provides a method for operating a silane reactive distillation column for increasing production capacity according to any one of the foregoing claims, comprising:

[0015] The raw material, trichlorosilane, is fed into the reactive distillation column from the top of the reaction section. A disproportionation reaction occurs continuously in the reaction section, producing dichlorosilane and monochlorosilane, ultimately yielding silane and silicon tetrachloride. The silane-containing gaseous material rises into the rectification section, while the high-boiling-point chlorosilane returns to the reaction section. High-purity gaseous silane at the top of the column is condensed into liquid in the top condenser, with some being refluxed and the rest collected as product. A portion of the byproducts generated in the reaction section is transferred through an oil collection tank to a distributor in the lower reaction section for further separation and storage. A portion of the useful byproducts continues to react in the reaction section, with the byproduct components gradually concentrated in the bottom of the column and discharged from the system. The silicon tetrachloride-containing liquid material flows downwards into the stripping section, while the chlorosilane, as a reactant, returns to the reaction section. High-purity silicon tetrachloride is collected from the bottom of the column.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0017] This invention provides a silane reactive distillation column for increasing production capacity and its operating method. Under the premise of ensuring normal reaction and separation, this invention adds an oil collection tank and an overflow device at the bottom of the packing section to concentrate and separate some by-products and products. When the by-products are removed in time, the by-products in the reaction section are reduced, which improves the progress of the forward reaction, increases the reaction efficiency, and yields more products. Attached Figure Description

[0018] Figure 1 This is a structural diagram of a silane reactive distillation column for improving production capacity provided in an embodiment of the present invention;

[0019] Figure 2This is a schematic diagram of the reaction section provided in an embodiment of the present invention.

[0020] In the diagram: 1. Rectifying section; 2. Reaction section; 21. Catalyst; 22. Distributor; 3. Stripping section; 4. Condenser; 5. Reboiler; 6. Packing section; 7. Oil collection tank; 8. By-product extraction line. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0022] Example 1

[0023] like Figure 1 , Figure 2 As shown in the figure, this embodiment introduces a silane reactive distillation column for improving production capacity. The upper section of the distillation column is the rectification section 1, the middle section is the reaction section 2, and the lower section is the stripping section 3. A condenser 4 is provided at the top of the distillation column. One end of the condenser 4 is connected to the top of the column with a condensing pipe, and another end of the condenser 4 is connected to the rectification section 1 with a reflux pipe. The other end of the condenser 4 is connected to the outside of the distillation column with an outlet pipe. A reboiler 5 is provided at the bottom of the distillation column. The inlet pipe of the reboiler 5 is connected to the bottom of the stripping section 3, and the outlet pipe of the reboiler 5 returns to the stripping section 3. The reaction section 2 has multiple sections, and each of the multiple reaction sections 2 contains... The system includes a catalyst 21 and a distributor 22. Adjacent sections of the multi-stage reaction section 2 are each equipped with a packing section 6. The bottom of each packing section 6 is equipped with an oil collection tank 7 and an overflow device. Both the oil collection tank 7 and the overflow device are connected to the distributor 22 in the lower reaction section 2. The lower part of the oil collection tank 7 is equipped with a byproduct extraction pipeline 8. The oil collection tank 7 is connected to the distributor 22 in the lower reaction section 2 via the byproduct extraction pipeline 8. The overflow device is located at a predetermined height inside the oil collection tank 7. The overflow device has an opening at the top and an overflow pipeline connected to its bottom. The overflow device is connected to the distributor 22 in the lower reaction section 2 via the overflow pipeline.

[0024] The overflow pipeline is equipped with a flow meter, and the outside of the overflow pipeline is provided with a heat insulation layer; the oil collection tank 7 is equipped with a tuning fork switch, a regulating valve and a thermometer; the packing section 6 is provided with double-layer packing plates, and a catalyst 21 is provided between the double-layer packing plates; the height of the oil collection tank 7 is 800-1200mm below the packing section 6; the height of the inlet of the overflow device is 200-400mm from the oil collector.

[0025] The following description, in conjunction with a preferred embodiment, illustrates the content involved in the above embodiments.

[0026] like Figure 1 , Figure 2 As shown, the reactive distillation column is divided into three sections: the upper section is the rectification section 1, the middle section is the reaction section 2, and the lower section is the stripping section 3. A condenser 4 is installed at the top of the column, with a condenser tube connecting one end to the top and a reflux pipe returning the product to the rectification section 1. The condenser 4 also has an outlet pipe connecting to the outside of the column. A reboiler 5 is installed at the bottom of the column, with its inlet pipe connected to the bottom of the stripping section 3 and its outlet pipe returning to the stripping section 3. The feedstock, trichlorosilane, originates from the reaction section 2. The material enters the reactive distillation column at the top, where it undergoes three disproportionation reactions in reaction section 2, producing dichlorosilane and monochlorosilane, ultimately generating silane and silicon tetrachloride. The silane-containing gaseous material flows upward into rectification section 1, while the high-boiling-point chlorosilane returns to reaction section 2. The high-purity gaseous silane at the top of the column is condensed into liquid in the top condenser 4, with part being refluxed and part being collected as product. The silicon tetrachloride-containing liquid material flows downward into stripping section 3, where the chlorosilanes (such as trichlorosilane, dichlorosilane, and monochlorosilane) that are reactants return to reaction section 2, and high-purity silicon tetrachloride is collected from the bottom of the column.

[0027] Because the separation efficiency of reaction section 2 is lower than that of rectification section 1 and stripping section 3, and because the byproducts generated in reaction section 2 are not effectively removed while the product is obtained, the forward reaction efficiency is reduced, which affects the increase of silane gas production capacity. If the separation efficiency is increased by increasing the reflux flow rate or other means, it will lead to an increase in energy consumption and a further reduction in reaction efficiency, and the efficiency of reactive distillation will not be maximized. At this point, if, under the premise of ensuring normal reaction and separation, the packing height of the rectification section 1 or stripping section 3 is increased by 50% between the two catalyst sections 21 (at this time, the separation section height of the reaction tower needs to be increased), some by-products and products are concentrated and separated. An oil collection tank 7 and an overflow device are added at the bottom of the added packing section 6. The overflow device is set at a predetermined height inside the oil collection tank 7. The top of the overflow device is open and the bottom is connected to an overflow pipeline. The overflow device is connected to the distributor 22 in the lower reaction section 2 through the overflow pipeline. A by-product extraction pipeline 8 is added at the bottom of the oil collection tank 7 to the distributor 22 at the bottom of the lower reaction section 2 for further separation and storage. Some useful by-products continue to react in the reaction section 2, and the heavy by-product components are gradually concentrated in the tower bottom and discharged from the system. The extraction flow rate can be adjusted according to the temperature changes of the reaction section 2, and the extraction flow rate should be controlled to ensure the orderly progress of the entire reaction and separation. When byproducts are removed in time, the amount of byproducts in reaction section 2 decreases, which accelerates the forward reaction, increases reaction efficiency, and yields more products.

[0028] Oil collection tank 7: As a facility for collecting and distributing liquid phase materials, the distributor 22 at the bottom of the catalyst 21 is adjusted according to the tuning fork switch of the oil collection tank 7. If there is a large liquid flow, it can overflow to the distributor 22 at the bottom of the oil collection tank 7 and enter the reaction section 2.

[0029] Regulating valve: Used for regulating the liquid phase flow rate from oil collection tank 7 to the lower part of catalyst section 21 in oil collection tank 7.

[0030] Example 2

[0031] This embodiment provides a method for operating a silane reactive distillation column for increasing production capacity according to any one of Embodiment 1, comprising:

[0032] The raw material trichlorosilane is fed into the reactive distillation column from the top of reaction section 2. In reaction section 2, a disproportionation reaction occurs continuously, producing dichlorosilane and monochlorosilane, ultimately generating silane and silicon tetrachloride. The silane-containing gaseous material flows upward into rectification section 1, while the high-boiling-point chlorosilane returns to reaction section 2. The high-purity gaseous silane at the top of the column is condensed into liquid in the top condenser 4, with part being refluxed and part being collected as product. A portion of the byproducts generated in reaction section 2 is transferred through the oil collection tank 7 to the distributor 22 in the lower reaction section 2 for further separation and storage. A portion of the useful byproducts continues to react in reaction section 2, with the byproduct components gradually concentrated in the bottom of the column and discharged from the system. The silicon tetrachloride-containing liquid material flows downward into stripping section 3, while the chlorosilane, as a reactant, returns to reaction section 2. High-purity silicon tetrachloride is collected from the bottom of the column.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silane reactive distillation column for increasing production capacity, characterized in that, The distillation column has a rectification section (1) at the top, a reaction section (2) at the middle, and a stripping section (3) at the bottom. A condenser (4) is located at the top of the distillation column. One end of the condenser (4) has a condenser tube connected to the top of the column, and another end of the condenser (4) has a reflux pipe returning the condenser (4) to the rectification section (1). The other end of the condenser (4) has an outlet pipe connected to the outside of the distillation column. A reboiler (5) is located at the bottom of the distillation column. The inlet pipe of the reboiler (5) is connected to the stripping section. The bottom of section (3) is connected, and the outlet pipe of the reboiler (5) returns to the stripping section (3). The reaction section (2) is provided with multiple sections, and each of the multiple reaction sections (2) is provided with a catalyst (21) and a distributor (22). Each of the adjacent parts of the multiple reaction sections (2) is provided with a packing section (6). The bottom of the packing section (6) is provided with an oil collection tank (7) and an overflow device. The oil collection tank (7) and the overflow device are both connected to the distributor (22) in the lower reaction section (2). The lower part of the oil collection tank (7) is provided with a by-product extraction pipeline (8), and the oil collection tank (7) is connected to the distributor (22) in the lower reaction section (2) through the by-product extraction pipeline (8); The overflow device is set at a set height inside the oil collection tank (7). The top of the overflow device is open and the bottom is connected to an overflow pipeline. The overflow device is connected to the distributor (22) in the lower reaction section (2) through the overflow pipeline. The packing section (6) is provided with a double layer of packing sheets, and a catalyst (21) is provided between the double layer of packing sheets.

2. The silane reactive distillation column for increasing production capacity according to claim 1, characterized in that, The overflow pipeline is equipped with a flow meter, and the outside of the overflow pipeline is provided with a heat insulation layer.

3. The silane reactive distillation column for increasing production capacity according to claim 1, characterized in that, The oil collection tank (7) is equipped with a tuning fork switch, a regulating valve, and a thermometer.

4. The silane reactive distillation column for increasing production capacity according to claim 1, characterized in that, The height of the oil collection tank (7) is 800-1200mm below the packing section (6).

5. The silane reactive distillation column for increasing production capacity according to claim 1, characterized in that, The height of the inlet of the overflow device is 200-400mm inside the oil collection tank (7).

6. The silane reactive distillation column for increasing production capacity according to claim 1, characterized in that, The reaction section (2) has three sections.

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