A device for producing high-purity silane from trichlorosilane and a method thereof

Abstract

The application discloses a device for producing high-purity silane from trichlorosilane, which comprises a reaction rectifying tower, an auxiliary reaction system, a multistage condensing system, a booster pump and a rectifying system; the side line of the reaction rectifying tower is connected with the auxiliary reaction system; the feed inlet of the multistage condensing system is connected with the top of the reaction rectifying tower, and the liquid phase discharge port of the multistage condensing system is connected with the reaction rectifying tower; the discharge port of the multistage condensing system is connected with the feed inlet of the booster pump, and the discharge port of the booster pump is connected with the rectifying system; and the application further discloses a method for producing high-purity silane by using the device. The device has the advantages of low energy consumption, high reaction efficiency, safety and environmental protection, and high product purity.

Description

Technical Field

[0001] This invention relates to the field of silane technology, and in particular to an apparatus and method for producing high-purity silanes from trichlorosilane. Background Technology

[0002] Silane, also known as monosilane, silane, or tetrahydrosilane, is an amorphous semiconductor, amorphous silicon. It has become the most important specialty gas used in semiconductor microelectronics processes for the fabrication of various microelectronic thin films, including single-crystal films, microcrystalline films, polycrystalline films, silicon oxide, silicon nitride, and metal silicides. The application of silane as a silicon-containing thin film and coating has expanded from the traditional microelectronics industry to various fields such as steel, machinery, chemicals, and optics. Another potential application of silane is in the manufacture of high-performance ceramic engine parts, especially with increasing attention being paid to the technology of using silane to manufacture silicide (Si3N4, SiC, etc.) micropowders.

[0003] The main methods for preparing silanes can be categorized into the silicon-magnesium alloy method, the sodium aluminum hydride method, and the trichlorosilane (TCS) disproportionation method. Among these, the trichlorosilane disproportionation method was developed by Union Carbide Corporation (UCC). This process primarily involves the hydrogenation of silicon tetrachloride (STC) to produce trichlorosilane, followed by a disproportionation reaction to produce dichlorosilane (DCS). The dichlorosilane then undergoes another disproportionation reaction to produce silane. The disproportionation reaction is carried out in a tower reactor, making it ideal for large-scale production with high efficiency and low cost. The reaction products are easily separated from the silane, yielding high-purity silanes. The reaction conditions are mild, energy consumption is low, and operation is easy to control, making it the mainstream method for silane production.

[0004] For example, CN103172071B discloses an apparatus and method for preparing high-purity silane by disproportionation distillation of trichlorosilane. The apparatus consists of a disproportionation distillation process, a silicon tetrachloride absorption process, a fixed-bed adsorption process, and a product bottling process. The apparatus uses a two-step disproportionation reaction and utilizes the distillation separation effect of the reactive distillation column to finally obtain a mixed gas of silane and dichlorosilane at the top of the column. After subsequent absorption, adsorption, and other separation processes, a high-purity silane product is obtained.

[0005] For example, CN106241813B discloses a system and method for producing high-purity silane from trichlorosilane, including a reaction tower, a multi-stage condenser, a compressor, a light-duty removal tower, and a product tower. Utilizing the significant boiling point difference between silane and other components in the reaction system, a multi-stage condenser replaces the rectification section at the top of the reaction tower in existing technologies, reducing the tower height and saving on equipment investment. The multi-stage condenser, combined with cold sources of different temperatures and qualities, allows for multi-stage partial condensation of the gas phase from the reaction tower, reducing cryogenic load and effectively decreasing operating costs and energy consumption.

[0006] For example, CN218620354U discloses a device for producing high-purity silane from trichlorosilane at a capacity of 10,000 tons. The device includes at least a reactive distillation column, a condensation system, a silane distillation column, and a condensation and pressurization system. This device makes reasonable use of the cold source and adopts a multi-stage condensation system for multiple condensation heat exchange. The grade of the cold source gradually increases, the flow rate of the cooled crude silane gradually decreases, and the purity gradually increases. This minimizes the power of the high-grade cold source at low temperature, thereby improving energy utilization.

[0007] For example, CN103241743B discloses a reactive distillation method and equipment for the direct disproportionation of trichlorosilane to prepare silanes, which consists of a trichlorosilane partition distillation column, a disproportionation reactive distillation column, a silane purification column, and a silicon tetrachloride separation column connected together. This invention achieves a one-step disproportionation reaction in a single reactive distillation column, simplifying the equipment and avoiding a large amount of material separation and recycling reactions, shortening the process, saving energy and reducing consumption, and resulting in higher purity silane products.

[0008] All of the above patents use reactive distillation columns as reactors. However, due to the different temperatures inside the reactive distillation column, the upper temperature is lower than the lower temperature, resulting in inconsistent temperatures in the reaction section of the reactive distillation column. The lower temperature of the reaction section is high, and the upper temperature is low. The catalyst efficiency in the low-temperature zone is low, resulting in incomplete disproportionation reaction and low reaction conversion rate. Summary of the Invention

[0009] This invention addresses the shortcomings of existing technologies by providing an apparatus and method for producing high-purity silanes from trichlorosilane. Using trichlorosilane as a raw material, high-purity silanes are prepared using reactive distillation technology. This invention features low energy consumption, high reaction efficiency, safety and environmental friendliness, and high product purity.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: an apparatus for producing high-purity silane from trichlorosilane, comprising a reactive distillation column, an auxiliary reaction system, a multi-stage condensation system, a booster pump, and a distillation system. A side stream from the reactive distillation column is connected to the auxiliary reaction system. The feed inlet of the multi-stage condensation system is connected to the top of the reactive distillation column, and the liquid phase outlet of the multi-stage condensation system is connected to the reactive distillation column. The outlet of the multi-stage condensation system is connected to the feed inlet of the booster pump, and the outlet of the booster pump is connected to the distillation system.

[0011] In a preferred embodiment of the present invention, the reactive distillation column comprises a rectification section, a reaction section, and a stripping section. The upper part of the reactive distillation column is provided with a rectification section, the middle part with a reaction section, and the lower part with a stripping section. The reaction section is provided with a disproportionation catalyst, and the rectification section and the stripping section are provided with fractionation packing. The bottom of the reactive distillation column is provided with a reactive distillation column reboiler, and the trichlorosilane feedstock enters the reactive distillation column from the reaction section.

[0012] In a preferred embodiment of the present invention, the auxiliary reaction system includes a pump, a primary heat exchanger, a secondary heat exchanger, and an auxiliary reactor connected in series. The sampling outlet of the reactive distillation column is connected to the feed inlet of the pump. The discharge outlet of the auxiliary reactor is connected to the middle of the reactive distillation column through the primary heat exchanger. The reaction products of the auxiliary reactor enter the reactive distillation column after exchanging heat with the primary heat exchanger.

[0013] In a preferred embodiment of the present invention, the auxiliary reaction system includes a condenser, a storage tank, a pump, a primary heat exchanger, a secondary heat exchanger, and an auxiliary reactor connected in series. The sampling outlet of the reactive distillation column is connected to the feed inlet of the condenser. The discharge outlet of the auxiliary reactor is connected to the middle of the reactive distillation column through the primary heat exchanger. The reaction products of the auxiliary reactor enter the reactive distillation column after exchanging heat with the primary heat exchanger.

[0014] In a preferred embodiment of the present invention, the multi-stage condensation system includes a primary condenser, a secondary condenser, a tertiary condenser, an economizer, and a cryostat connected in series. The gas inlet of the primary condenser is connected to the top of the reactive distillation column, and the liquid outlets of the primary, secondary, and tertiary condensers are connected to the upper part of the reactive distillation column. The outlet of the cryostat is connected to the inlet of the booster pump, and the outlet of the booster pump is connected to the distillation system through the economizer. The material pressurized by the booster pump enters the distillation system after heat exchange with the economizer.

[0015] In a preferred embodiment of the present invention, the distillation system includes a first distillation column and a second distillation column. The first distillation column is provided with a first distillation column condenser at the top and a first distillation column reboiler at the bottom. The second distillation column is provided with a second distillation column condenser at the top and a second distillation column reboiler at the bottom. The bottom of the second distillation column is connected in parallel to the outlet of the first-stage heat exchanger.

[0016] The present invention also provides a method for producing high-purity silane using the above-described apparatus, comprising the following steps:

[0017] (1) Trichlorosilane is fed into the reactive distillation column, and after disproportionation reaction and distillation purification, crude silane is obtained at the top of the column and liquid silicon tetrachloride is collected at the bottom of the column; the material collected from the side of the reaction section of the reactive distillation column is fed into the auxiliary reactor for further reaction and then returned to the reactive distillation column.

[0018] (2) The crude silane obtained from the top of the reactive distillation column is fed into the condensation system to obtain condensate and liquid crude silane. The condensate is refluxed back to the reactive distillation column to continue the disproportionation reaction.

[0019] (3) The liquid crude silane obtained in step (2) is fed into the booster pump, and after being pressurized, it is fed into the distillation system for purification to obtain a high-purity silane product.

[0020] In a preferred embodiment of the present invention, the pressure of the reactive distillation column is 0.3~0.8MPa and the temperature is 50~160℃.

[0021] In a preferred embodiment of the present invention, the reaction temperature of the auxiliary reaction system is 80~180℃ and the pressure is 1.0~3.0MPa.

[0022] In a preferred embodiment of the present invention, the pressure of the booster pump is 1.5~5.0MPa; the pressure of the distillation system is 1.5~4.0MPa, and the temperature is -20~90℃.

[0023] To address the problem in existing reactive distillation columns where inconsistent temperatures (higher at the top than the bottom), leading to incomplete disproportionation and low conversion rates due to low catalyst efficiency in the low-temperature zone, this invention optimizes the production equipment by incorporating an auxiliary reaction system. This system allows for convenient temperature control, facilitating the disproportionation reaction, reducing side reactions, and significantly improving reaction efficiency and product quality. Simultaneously, it reduces the load on the reactive distillation column, further enhancing catalyst utilization and effectively solving the low-temperature efficiency problem. Furthermore, the auxiliary reaction system effectively reduces the height of the reactive distillation column, saving on equipment investment costs. In actual production, the side stream from the reactive distillation column can be gaseous, liquid, or a mixture of both. The gaseous or mixed stream is condensed and stored in a tank before being pumped, heated by a primary heat exchanger, and then fed into the auxiliary reactor. The liquid stream can be directly pumped or stored in the tank first. The number and size of condensers and storage tanks can be set according to actual production needs.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] With high reaction efficiency and good product quality, this invention optimizes the production equipment and sets up an auxiliary reaction system, which can conveniently control the reaction temperature to make the disproportionation reaction easier, reduce the occurrence of side reactions, and significantly improve reaction efficiency and product quality, with product purity reaching 99.9999%. At the same time, it also reduces the load on the reactive distillation column, further improves the utilization rate of the catalyst, and effectively solves the problem of low efficiency at low temperatures.

[0026] With low energy consumption, this invention utilizes a multi-stage condensation system to rationally utilize the cold source. Through multiple condensation and heat exchange processes, the cold source grade gradually increases, the flow rate of the cooled crude silane gradually decreases, and the purity gradually increases. This minimizes the power consumption of the high-grade cold source at low temperatures, significantly improving energy efficiency. Connecting the outlet of the auxiliary reactor to the middle of the reactive distillation column via a primary heat exchanger effectively recovers heat. Connecting the outlet of the booster pump to the distillation system via an economizer allows the material cooled by the cryostat to serve as the economizer's cold source, further reducing energy consumption.

[0027] With low investment and low cost, this invention effectively reduces the height of the reactive distillation column by optimizing the production equipment and setting up an auxiliary reaction system, thus saving equipment investment costs.

[0028] Safe and environmentally friendly, this invention, by setting up an auxiliary reaction system, can conveniently control the reaction temperature to ensure the disproportionation reaction proceeds smoothly, greatly improving the safety of the reaction; by connecting the bottom of the second distillation column in parallel with the outlet of the first-stage heat exchanger, the heavy components in the bottom of the second distillation column can be returned to the auxiliary reactor for recycling, effectively reducing the emission of waste gas, wastewater, and solid waste and lowering production costs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the apparatus according to Embodiment 1 of the present invention;

[0030] Figure 2 This is a schematic diagram of the apparatus according to Embodiment 2 of the present invention;

[0031] Figure 3 This is a schematic diagram of the apparatus in Embodiment 3 of the present invention.

[0032] Wherein: 1 represents a reactive distillation column, 2 represents an auxiliary reactor, 3 represents a first distillation column, 4 represents a second distillation column, 5 represents a first-stage condenser, 6 represents a second-stage condenser, 7 represents a third-stage condenser, 8 represents an economizer, 9 represents a cryogenic reactor, 10 represents a booster pump, 11 represents a first-stage distillation column condenser, 12 represents a second-stage distillation column condenser, 13 represents a reactive distillation column reboiler, 14 represents a first-stage distillation column reboiler, 15 represents a second-stage distillation column reboiler, 16 represents a second-stage heat exchanger, 17 represents a first-stage heat exchanger, 18 represents a pump, 19 represents a storage tank, and 20 represents a condenser. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example

[0034] like Figure 1 As shown, an apparatus for producing high-purity silane from trichlorosilane includes a reactive distillation column 1, an auxiliary reaction system, a multi-stage condensation system, a booster pump 10, and a distillation system. The auxiliary reaction system includes a pump 18, a primary heat exchanger 17, a secondary heat exchanger 16, and an auxiliary reactor 2 connected in series. The multi-stage condensation system includes a primary condenser 5, a secondary condenser 6, a tertiary condenser 7, an economizer 8, and a cryotherm 9 connected in series. The distillation system includes a first distillation column 3 and a second distillation column 4. The top of the first distillation column 3 is equipped with... The first distillation column has a condenser 11 and a reboiler 14 at the bottom. The second distillation column 4 has a condenser 12 at the top and a reboiler 15 at the bottom. The reactive distillation column 1 has a rectification section at the top, a reaction section in the middle, and a stripping section at the bottom. The reaction section is filled with a four-stage disproportionation catalyst (basic anion exchange resin), and the rectification and stripping sections are filled with fractionation packing (structured packing). The rectification section can recover unreacted chlorosilanes, and the stripping section can preliminarily separate TCS. Along with STC, a reboiler 13 is installed at the bottom of the reactive distillation column 1. Trichlorosilane feedstock enters the reactive distillation column 1 from the middle reaction section. A side outlet is provided in the middle of the reactive distillation column 1 for collecting the liquid reaction mixture. The side outlet of the reactive distillation column 1 is connected to the feed inlet of pump 18. The outlet of auxiliary reactor 2 is connected to the reaction section of reactive distillation column 1 through a primary heat exchanger 17. The reaction products of auxiliary reactor 2 enter the reaction section of reactive distillation column 1 for further reaction after exchanging heat with the primary heat exchanger 17. The gas inlet of the primary condenser 5 is connected to the top gas inlet of reactive distillation column 1. The liquid outlets of the first-stage condenser 5, the second-stage condenser 6, and the third-stage condenser 7 are connected to the upper condensate reflux port of the reactive distillation column 1, respectively. The outlet of the cryogenic cooler 9 is connected to the inlet of the booster pump 10. The outlet of the booster pump 10 is connected to the middle inlet of the first distillation column 3 through the economizer 8. After being pressurized by the booster pump 10, the material enters the first distillation column 3 for separation after heat exchange with the economizer 8. The economizer 8 uses the material cooled by the cryogenic cooler 9 as a cold source for heat exchange. The bottom liquid outlet of the second distillation column 4 is connected in parallel with the outlet of the first-stage heat exchanger 17.

[0035] The process flow for producing high-purity silane using this device is as follows:

[0036] (1) Trichlorosilane is fed into the reactive distillation column from the middle reaction section. After disproportionation and distillation purification, crude silane is obtained at the top of the column and liquid silicon tetrachloride is collected from the bottom of the column. The liquid material collected from the side of the reaction section of the reactive distillation column is preheated by the first-stage heat exchanger and the second-stage heat exchanger and then fed into the auxiliary reactor for further reaction. The product obtained from the reaction is then returned to the reaction section of the reactive distillation column after heat recovery in the first-stage heat exchanger.

[0037] (2) The crude silane obtained from the top of the reactive distillation column is cooled sequentially through a primary condenser, a secondary condenser, and a tertiary condenser to obtain a condensate containing unreacted trichlorosilane and the products dichlorosilane and monochlorotrichlorosilane (MCS) and a gaseous crude silane. The condensate is refluxed back to the reactive distillation column to continue the disproportionation reaction.

[0038] (3) The gaseous crude silane obtained by condensation in step (2) is sequentially fed into the economizer and the cryogenic reactor, and after condensation, liquid crude silane is obtained.

[0039] (4) The liquid crude silane obtained in step (3) is fed into a booster pump and then fed into the first distillation column for distillation. The light component impurities are discharged from the top of the first distillation column. The bottom of the first distillation column is the liquid phase after the light components have been removed. It is fed into the second distillation column for distillation. The heavy components (TCS, DCS, MCS mixture) separated from the bottom of the second distillation column are returned to the auxiliary reactor. The high-purity silane product is obtained at the top of the column.

[0040] The process parameters are controlled as follows:

[0041] The temperature of the reactive distillation column is controlled at 50℃, and the pressure is controlled at 0.3MPa;

[0042] The auxiliary reactor temperature is controlled at 80℃ and the pressure is controlled at 1.0 MPa;

[0043] The first distillation column operates at a pressure of 1.5 MPa, a top temperature of -20°C, and a bottom temperature of 20°C.

[0044] The second distillation column operates at a pressure of 1.5 MPa, with a top temperature of -20°C and a bottom temperature of 20°C.

[0045] Results: The reaction process was stable and controllable, yielding a high-purity silane product with a purity of 99.9999%. Example

[0046] like Figure 2As shown, an apparatus for producing high-purity silane from trichlorosilane includes a reactive distillation column 1, an auxiliary reaction system, a multi-stage condensation system, a booster pump 10, and a distillation system. The auxiliary reaction system includes a condenser 20, a storage tank 19, a pump 18, a primary heat exchanger 17, a secondary heat exchanger 16, and an auxiliary reactor 2 connected in series. The multi-stage condensation system includes a primary condenser 5, a secondary condenser 6, a tertiary condenser 7, an economizer 8, and a cryotherm 9 connected in series. The distillation system includes a first distillation column 3 and a second distillation column 4. Column 3 is equipped with a first distillation column condenser 11 at the top and a first distillation column reboiler 14 at the bottom; column 4 is equipped with a second distillation column condenser 12 at the top and a second distillation column reboiler 15 at the bottom; the reactive distillation column 1 has a rectification section at the top, a reaction section in the middle, and a stripping section at the bottom. The reaction section is filled with a four-stage disproportionation reaction catalyst (basic anion exchange resin), and the rectification and stripping sections are filled with fractionation packing (structured packing). The rectification section can recover unreacted chlorosilanes, and the stripping section can preliminarily separate TCS. Along with STC, a reboiler 13 is installed at the bottom of the reactive distillation column 1. Trichlorosilane feedstock enters the reactive distillation column 1 from the reaction section. The reactive distillation column 1 is equipped with a side outlet for collecting the vapor reaction mixture. The side outlet of the reactive distillation column 1 is connected to the feed inlet of the condenser 20. The outlet of the auxiliary reactor 2 is connected to the reaction section of the reactive distillation column 1 through a primary heat exchanger 17. The reaction products of the auxiliary reactor 2 enter the reaction section of the reactive distillation column 1 for further reaction after exchanging heat with the primary heat exchanger 17. The vapor inlet of the primary condenser 5 is connected to the top vapor inlet of the reactive distillation column 1. The liquid outlets of the first-stage condenser 5, the second-stage condenser 6, and the third-stage condenser 7 are connected to the upper condensate reflux port of the reactive distillation column 1, respectively. The outlet of the cryogenic cooler 9 is connected to the inlet of the booster pump 10. The outlet of the booster pump 10 is connected to the middle inlet of the first distillation column 3 through the economizer 8. After being pressurized by the booster pump 10, the material enters the first distillation column 3 for separation after heat exchange with the economizer 8. The economizer 8 uses the material cooled by the cryogenic cooler 9 as a cold source for heat exchange. The bottom liquid outlet of the second distillation column 4 is connected in parallel with the outlet of the first-stage heat exchanger 17.

[0047] The process flow for producing high-purity silane using this device is as follows:

[0048] (1) Trichlorosilane is fed into the reactive distillation column from the middle reaction section. After disproportionation reaction and distillation purification, crude silane is obtained at the top of the column and liquid silicon tetrachloride is collected at the bottom of the column. The gaseous material collected from the side of the reaction section of the reactive distillation column is first cooled into liquid phase by a condenser, and then preheated by a primary heat exchanger and a secondary heat exchanger before being fed into an auxiliary reactor for further reaction. The product obtained from the reaction is then returned to the reaction section of the reactive distillation column after heat recovery in the primary heat exchanger.

[0049] (2) The crude silane obtained from the top of the reactive distillation column is cooled sequentially through a primary condenser, a secondary condenser, and a tertiary condenser to obtain a condensate containing unreacted trichlorosilane and the products dichlorosilane and monochlorotrichlorosilane (MCS) and a gaseous crude silane. The condensate is refluxed back to the reactive distillation column to continue the disproportionation reaction.

[0050] (3) The gaseous crude silane obtained by condensation in step (2) is sequentially fed into the economizer and the cryogenic reactor, and after condensation, liquid crude silane is obtained.

[0051] (4) The liquid crude silane obtained in step (3) is fed into a booster pump and then fed into the first distillation column for distillation. The light component impurities are discharged from the top of the first distillation column. The bottom of the first distillation column is the liquid phase after the light components have been removed. It is fed into the second distillation column for distillation. The heavy components (TCS, DCS, MCS mixture) separated from the bottom of the second distillation column are returned to the auxiliary reactor. The high-purity silane product is obtained at the top of the column.

[0052] The process parameters are:

[0053] The temperature of the reactive distillation column is controlled at 100℃, and the pressure is controlled at 0.5MPa;

[0054] The auxiliary reactor temperature is controlled at 120℃ and the pressure is controlled at 2.0 MPa;

[0055] The first distillation column operates at a pressure of 2.5 MPa, with a top temperature of -50°C and a bottom temperature of 50°C.

[0056] The second distillation column operates at a pressure of 2.5 MPa, with a top temperature of -50°C and a bottom temperature of 50°C.

[0057] Results: The reaction process was stable and controllable, and a high-purity silane product with a purity of 99.9999% was obtained. Example

[0058] like Figure 3As shown, an apparatus for producing high-purity silane from trichlorosilane includes a reactive distillation column 1, an auxiliary reaction system, a multi-stage condensation system, a booster pump 10, and a distillation system. The auxiliary reaction system includes a condenser 20, a storage tank 19, a pump 18, a primary heat exchanger 17, a secondary heat exchanger 16, and an auxiliary reactor 2 connected in series. The multi-stage condensation system includes a primary condenser 5, a secondary condenser 6, a tertiary condenser 7, an economizer 8, and a cryotherm 9 connected in series. The distillation system includes a first distillation column 3 and a second distillation column 4. Column 3 is equipped with a first distillation column condenser 11 at the top and a first distillation column reboiler 14 at the bottom; column 4 is equipped with a second distillation column condenser 12 at the top and a second distillation column reboiler 15 at the bottom; the reactive distillation column 1 has a rectification section at the top, a reaction section in the middle, and a stripping section at the bottom. The reaction section is filled with a four-stage disproportionation reaction catalyst (basic anion exchange resin), and the rectification and stripping sections are filled with fractionation packing (structured packing). The rectification section can recover unreacted chlorosilanes, and the stripping section can preliminarily separate TCS. Along with STC, a reboiler 13 is installed at the bottom of the reactive distillation column 1. Trichlorosilane feedstock enters the reactive distillation column 1 from the reaction section. The reactive distillation column 1 is equipped with a first side outlet and a second side outlet. The first side outlet is used to collect the gaseous reaction mixture, and the second side outlet is used to collect the liquid reaction mixture. The first side outlet is connected to the feed inlet of the condenser 20, and the second side outlet is connected to the middle feed inlet of the storage tank 19. The outlet of the auxiliary reactor 2 is connected to the reaction section of the reactive distillation column 1 through a primary heat exchanger 17. The reaction products of the auxiliary reactor 2 enter the reaction section of the reactive distillation column 1 after exchanging heat with the primary heat exchanger 17 to continue the reaction. The vapor inlet of the first-stage condenser 5 is connected to the top vapor outlet of the reactive distillation column 1. The liquid outlets of the first-stage condenser 5, the second-stage condenser 6, and the third-stage condenser 7 are respectively connected to the upper condensate reflux outlet of the reactive distillation column 1. The outlet of the cryogenic cooler 9 is connected to the inlet of the booster pump 10. The outlet of the booster pump 10 is connected to the middle inlet of the first distillation column 3 through the economizer 8. After being pressurized by the booster pump 10, the material enters the first distillation column 3 for separation after heat exchange with the economizer 8. The economizer 8 uses the material cooled by the cryogenic cooler 9 as a cold source for heat exchange. The bottom liquid outlet of the second distillation column 4 is connected in parallel with the outlet of the first-stage heat exchanger 17.

[0059] The process flow for producing high-purity silane using this device is as follows:

[0060] (1) Trichlorosilane is fed into the reactive distillation column from the middle reaction section. After disproportionation reaction and distillation purification, crude silane is obtained at the top of the column and liquid silicon tetrachloride is collected at the bottom of the column. The gaseous material collected from the first side outlet of the reaction section of the reactive distillation column is cooled into liquid by the condenser and then enters the storage tank. The liquid material collected from the second side outlet of the reaction section of the reactive distillation column directly enters the storage tank. The material in the storage tank is then preheated by the first-stage heat exchanger and the second-stage heat exchanger and then fed into the auxiliary reactor for further reaction. The product obtained from the reaction is then returned to the reaction section of the reactive distillation column after heat recovery by the first-stage heat exchanger.

[0061] (2) The crude silane obtained from the top of the reactive distillation column is cooled sequentially through a primary condenser, a secondary condenser, and a tertiary condenser to obtain a condensate containing unreacted trichlorosilane and the products dichlorosilane and monochlorotrichlorosilane (MCS) and a gaseous crude silane. The condensate is refluxed back to the reactive distillation column to continue the disproportionation reaction.

[0062] (3) The gaseous crude silane obtained by condensation in step (2) is sequentially fed into the economizer and the cryogenic reactor, and after condensation, liquid crude silane is obtained.

[0063] (4) The crude liquid silane obtained in step (3) is fed into a booster pump and then into the first distillation column for distillation. The light component impurities are discharged from the top of the first distillation column. The bottom of the first distillation column is the liquid phase after the removal of light components, which is then fed into the second distillation column for distillation. The heavy components (a mixture of TCS, DCS, and MCS) separated from the bottom of the second distillation column are returned to the auxiliary reactor. High-purity silane product is obtained at the top of the column.

[0064] The process parameters are:

[0065] The temperature of the reactive distillation column is controlled at 160℃, and the pressure is controlled at 0.8MPa;

[0066] The auxiliary reactor temperature is controlled at 180℃ and the pressure is controlled at 3.0 MPa;

[0067] The first distillation column operates at a pressure of 4 MPa, with a top temperature of -90°C and a bottom temperature of 90°C.

[0068] The second distillation column operates at a pressure of 4 MPa, with a top temperature of -90°C and a bottom temperature of 90°C.

[0069] Results: The reaction process was stable and controllable, and a high-purity silane product with a purity of 99.9999% was obtained.

Claims

1. An apparatus for producing high-purity silane from trichlorosilane, comprising a reactive distillation column, an auxiliary reaction system, a multi-stage condensation system, a booster pump, and a distillation system, characterized in that, The side feed outlet of the reactive distillation column is connected to the auxiliary reaction system, which includes a pump, a primary heat exchanger, a secondary heat exchanger, and an auxiliary reactor connected in series. The side feed outlet of the reactive distillation column is connected to the feed inlet of the pump. The discharge outlet of the auxiliary reactor is connected to the middle of the reactive distillation column through the primary heat exchanger. The reaction products of the auxiliary reactor enter the reactive distillation column after exchanging heat with the primary heat exchanger. The feed inlet of the multi-stage condensation system is connected to the top of the reactive distillation column, and the liquid phase discharge outlet of the multi-stage condensation system is connected to the reactive distillation column. The discharge outlet of the multi-stage condensation system is connected to the feed inlet of the booster pump, and the discharge outlet of the booster pump is connected to the distillation system.

2. The apparatus for producing high-purity silane from trichlorosilane according to claim 1, characterized in that, The reactive distillation column consists of a rectification section, a reaction section, and a stripping section. The upper part of the reactive distillation column is equipped with a rectification section, the middle part with a reaction section, and the lower part with a stripping section. The reaction section is equipped with a disproportionation catalyst, and the rectification section and the stripping section are equipped with fractionation packing. The bottom of the reactive distillation column is equipped with a reactive distillation column reboiler. Trichlorosilane feedstock enters the reactive distillation column from the reaction section.

3. The apparatus for producing high-purity silane from trichlorosilane according to claim 1, characterized in that, A condenser and a storage tank are connected in series between the reactive distillation column and the pump, and the side outlet of the reactive distillation column is connected to the feed inlet of the condenser.

4. The apparatus for producing high-purity silane from trichlorosilane according to claim 1, characterized in that, The multi-stage condensation system includes a primary condenser, a secondary condenser, a tertiary condenser, an economizer, and a cryostat connected in series. The vapor inlet of the primary condenser is connected to the top of the reactive distillation column. The liquid outlets of the primary, secondary, and tertiary condensers are connected to the upper part of the reactive distillation column. The outlet of the cryostat is connected to the inlet of the booster pump. The outlet of the booster pump is connected to the distillation system through the economizer. The material pressurized by the booster pump enters the distillation system after heat exchange with the economizer.

5. The apparatus for producing high-purity silane from trichlorosilane according to claim 1 or 3, characterized in that, The distillation system includes a first distillation column and a second distillation column. The first distillation column is equipped with a first distillation column condenser at the top and a first distillation column reboiler at the bottom. The second distillation column is equipped with a second distillation column condenser at the top and a second distillation column reboiler at the bottom. The bottom of the second distillation column is connected in parallel to the outlet of the first-stage heat exchanger.

6. A method for producing high-purity silane from trichlorosilane using the apparatus of claim 1, characterized in that, Includes the following steps: (1) Trichlorosilane is fed into the reactive distillation column, and after disproportionation reaction and distillation purification, crude silane is obtained at the top of the column and liquid silicon tetrachloride is collected at the bottom of the column; the material collected from the side of the reaction section of the reactive distillation column is fed into the auxiliary reactor for further reaction and then returned to the reactive distillation column. (2) The crude silane obtained from the top of the reactive distillation column is fed into the condensation system to obtain condensate and liquid crude silane. The condensate is refluxed back to the reactive distillation column to continue the disproportionation reaction. (3) The liquid crude silane obtained in step (2) is fed into the booster pump, and after being pressurized, it is fed into the distillation system for purification to obtain a high-purity silane product.

7. The method for producing high-purity silane from trichlorosilane according to claim 6, characterized in that, The pressure of the reactive distillation column is 0.3~0.8MPa, and the temperature is 50~160℃.

8. The method for producing high-purity silane from trichlorosilane according to claim 6, characterized in that, The auxiliary reaction system has a reaction temperature of 80~180℃ and a pressure of 1.0~3.0MPa.

9. The method for producing high-purity silane from trichlorosilane according to claim 6, characterized in that, The pressure of the booster pump is 1.5~5.0MPa; the pressure of the distillation system is 1.5~4.0MPa, and the temperature is -20~90℃.

Images