Silane gas production system and method based on double reactive distillation towers

Abstract

The invention provides a silane gas production system and method based on double reactive distillation columns, the system comprises a second reactive distillation column (2) arranged in the silane gas production system, the middle input end of the second reactive distillation column (2) is connected with the bottom output end of a silane distillation column (3) in the silane gas production system, and the middle input end of the second reactive distillation column (2) is connected with the bottom output end of the silane distillation column (3). Receiving the output intermediate mixture and carrying out disproportionation reaction; the top output end of the second reactive distillation tower (2) is connected with the top output end of the first reactive distillation tower (1) in the silane gas production system, and substances in the second reactive distillation tower (2) are mixed for subsequent treatment; the bottom output end of the second reactive distillation tower (2) is connected with the middle input end of the first reactive distillation tower (1) in the silane gas production system, and the output substances are subjected to disproportionation reaction. According to the method, the silane gas production based on the double reactive distillation towers is realized by adopting the system.

Description

Technical Field

[0001] The invention relates to a silane gas production system and method, in particular to a silane gas production system and method based on a double reaction distillation tower. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] The silane gas production process is divided into two production processes: fixed bed reaction process and reactive distillation process. Both processes use chlorosilane as raw material. Due to factors such as production conversion rate and changes in reaction components, not all chlorosilane in the system will participate in the reaction and the generated silane gas will not be fully purified as a product. Maximizing the yield of silane gas has been the research direction of silane gas production.

[0004] In the existing production process, the production cost of the fixed bed reaction process is too high; the output of silane gas in the reactive distillation production process is affected by the material composition. The output silane gas is dissolved in the chlorosilane material and needs to be gradually purified and separated to obtain the silane gas product. The separated light component chlorosilane continues to return to the reactive distillation tower to participate in the reaction, which increases the separation load of the reactive distillation tower and increases energy consumption.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a silane gas production system and method based on a double reaction distillation tower in view of the deficiencies in the prior art.

[0007] In order to solve the above technical problems, the present invention discloses a silane gas production system and method based on a double reaction distillation tower, the system comprising:

[0008] A second reaction distillation tower is arranged in the silane gas production system, wherein the middle input end of the second reaction distillation tower is connected to the bottom output end of the silane distillation tower in the silane gas production system, receives the intermediate mixture outputted therefrom and performs a disproportionation reaction;

[0009] The top output end of the second reaction distillation tower is connected to the top output end of the first reaction distillation tower in the silane gas production system, and the substances therein are mixed and then subsequently processed;

[0010] The bottom output end of the second reaction distillation tower is connected to the middle input end of the first reaction distillation tower in the silane gas production system to perform a disproportionation reaction on the output substances.

[0011] The silane gas production system comprises:

[0012] A first reaction distillation tower, wherein the middle input end of the first reaction distillation tower is used to receive trichlorosilane TCS transmitted by the upstream system and perform a disproportionation reaction; the bottom output end of the first reaction distillation tower outputs the liquid phase silicon tetrachloride STC produced by the reaction;

[0013] The top output end of the first reaction distillation tower is connected to the input end of the cooling and heat exchange system, and the crude silane produced by the reaction is cooled and heat exchanged to obtain liquid crude silane;

[0014] A first reaction distillation tower reboiler is also provided at the bottom of the first reaction distillation tower for providing heat therefor;

[0015] The output end of the cooling and heat exchange system is connected to the input end of the silane distillation tower. The silane distillation tower is used to distill the liquid crude silane input thereto. A silane distillation tower condenser is provided at the top of the silane distillation tower. The gas phase part at the top of the silane distillation tower is condensed into a liquid phase through the silane distillation tower condenser and serves as the reflux of the silane distillation tower, and the uncondensed part is discharged as a gas phase impurity. The side line output end of the silane distillation tower outputs silane, and the bottom output end of the silane distillation tower outputs the intermediate mixture. A silane distillation tower reboiler is provided at the bottom of the silane distillation tower to provide heat for it.

[0016] The cooling and heat exchange system comprises:

[0017] A primary condenser, a secondary condenser, a third condenser, a fourth heat exchanger and a fifth condenser connected in sequence;

[0018] Wherein, the condensate pipeline of the primary condenser is connected to a reflux tank, the reflux tank is used to store the condensate of the primary condenser, the reflux tank is connected to the top input end of the first reactive distillation tower through a reflux pump, and the reflux pump is used to pressurize the condensate;

[0019] The condensate pipelines of the secondary condenser and the tertiary condenser are connected to the middle input end of the first reactive distillation tower, and the condensate is used to continue the disproportionation reaction;

[0020] The fourth-stage heat exchanger uses the liquid crude silane condensed in the fifth-stage condenser as a cold source for heat exchange.

[0021] The cooling and heat exchange system further comprises:

[0022] The silane phase separation tank connected to the output end of the five-stage condenser is used to store the liquid crude silane. The output end of the silane phase separation tank is connected to a silane booster pump to pressurize the liquid crude silane and input it into a downstream device.

[0023] The intermediate mixture is a mixture of trichlorosilane TCS, dichlorodisilane DCS and monochlorotrisilane MCS.

[0024] The first reactive distillation tower comprises:

[0025] A first catalyst packing section, a first rectifying section and a first stripping section, wherein the first catalyst packing section is used for carrying out trichlorosilane TCS disproportionation reaction, the first stripping section is used for purifying silicon tetrachloride STC, and the first rectifying section is used for preliminary purification of silane;

[0026] Liquid silicon tetrachloride STC is obtained in the tower kettle of the first reactive distillation tower, and a gaseous silane mixture containing trichlorosilane TCS, dichlorodisilane DCS, monochlorotrisilane MCS and silane, i.e. crude silane, is obtained at the tower top;

[0027] The pressure in the first reaction distillation tower is set to 0.1Mpa(G)-0.4Mpa(G), and the temperature of the first catalyst packing section is set to 20°C to 150°C.

[0028] The second reactive distillation tower comprises:

[0029] A second catalyst packing section, a second rectifying section and a second stripping section, wherein the second catalyst packing section is used for carrying out trichlorosilane TCS disproportionation reaction, the second stripping section is used for carrying out trichlorosilane TCS purification, and the second rectifying section is used for preliminary purification of silane;

[0030] A mixture containing trichlorosilane TCS and dichlorodisilane DCS is obtained in the kettle of the second reaction distillation tower, and a second reaction distillation tower condenser is provided at the top of the tower to condense and obtain a gas phase silane mixture containing dichlorodisilane DCS, monochlorotrisilane MCS and silane, namely crude silane;

[0031] The crude silane is condensed again into liquid chlorosilane material through the condenser of the second reaction distillation tower, and returned to the second reaction distillation tower as the top reflux;

[0032] The second reaction distillation tower further includes a second reaction distillation tower reboiler, which is used to provide heat for the second reaction distillation tower;

[0033] The pressure in the second reaction distillation tower is set to 1.5Mpa(G)-0.6Mpa(G), and the temperature of the second catalyst packing section is set to 20°C to 150°C.

[0034] The inlet temperature of the first-stage condenser is set to 30°C to 100°C, and the outlet temperature is set to 20°C to 60°C;

[0035] The inlet temperature of the secondary condenser is set to 20°C to 60°C, and the outlet temperature is set to -20°C to 0°C;

[0036] The inlet temperature of the three-stage condenser is set to -20°C to 0°C, and the outlet temperature is set to -30°C to -60°C;

[0037] The inlet temperature of the heat medium in the four-stage heat exchanger is set to -30°C to -60°C, and the outlet temperature is set to -40°C to -70°C;

[0038] The inlet temperature of the five-stage condenser is set to -40°C to -70°C, and the outlet temperature is set to -70°C to -120°C;

[0039] The reflux pump is a magnetic pump or a shielded pump, which is used to increase the pressure to 0.3MPa(G) to 2.0MPa(G);

[0040] The silane booster pump is a magnetic pump or a shielded pump, which is used to increase the pressure to 0.6MPa(G) to 5.0MPa(G).

[0041] The tower pressure of the silane distillation tower is set to 0.5 MPa(G)-4.0 MPa(G), the tower top temperature is set to -20°C to -80°C, and the tower bottom temperature is set to 20°C to 80°C.

[0042] The present invention also proposes a method for producing silane gas based on a double reaction distillation tower, which is implemented using the above-mentioned system and includes:

[0043] Step 1, setting a second reactive distillation tower in a silane gas production system;

[0044] Step 2, the middle input end of the first reactive distillation tower in the silane gas production system receives trichlorosilane TCS transmitted by the upstream system, performs a disproportionation reaction, and outputs the liquid phase silicon tetrachloride STC produced by the reaction through its bottom output end;

[0045] Step 3: the top output end of the second reaction distillation tower is connected to the top output end of the first reaction distillation tower, and the gases outputted from the two are mixed and transmitted to the cooling and heat exchange system in the silane gas production system, and liquid crude silane is obtained after cooling and heat exchange; the bottom output end of the second reaction distillation tower is connected to the middle input end of the first reaction distillation tower, and the substance outputted from the bottom of the second reaction distillation tower is subjected to a disproportionation reaction;

[0046] Step 4, transferring the liquid crude silane obtained by the cooling and heat exchange system to a silane distillation tower for distillation, discharging gaseous impurities after distillation from the top output end of the silane distillation tower, outputting silane from the side line output end, and transferring the intermediate mixture from the bottom output end to the middle of the second reaction distillation tower for disproportionation reaction.

[0047] Beneficial effects:

[0048] In the existing method for producing silane gas based on reactive distillation, the present invention adds a reaction tower, and adds monochlorotrihydrogen silicon and dichlorodihydrogen silicon separated at the top of the original reactive distillation tower to react, so that this part of the material can produce silane gas under high conversion rate, thereby improving the silane gas output, and at the same time avoiding this part of the material from returning to the original reactive distillation tower, thereby reducing the separation load of the original reactive distillation tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0050] Figure 1 It is a schematic diagram of the overall architecture of the present invention.

[0051] in:

[0052] 1 is a reactive distillation tower No. 1; 2 is a reactive distillation tower No. 2; 3 is a silane distillation tower; 4 is a reflux tank; 5 is a silane phase separation tank; 6 is a reflux pump; 7 is a silane booster pump; 8 is a primary condenser; 9 is a secondary condenser; 10 is a tertiary condenser; 11 is a fourth-stage heat exchanger; 12 is a fifth-stage condenser; 13 is a silane distillation tower condenser; 14 is a reactive distillation tower No. 2 condenser; 15 is a reactive distillation tower No. 1 reboiler; 16 is a silane distillation tower reboiler; 17 is a reactive distillation tower No. 2 reboiler. DETAILED DESCRIPTION

[0053] The overall idea of ​​the present invention is as follows:

[0054] According to the existing reactive distillation production process and the characteristics that the reaction conversion rates of monochlorotrihydrogen silicon, dichlorodihydrogen silicon and trichlorosilane decrease in sequence, the light component chlorosilane (monochlorotrihydrogen silicon and dichlorodihydrogen silicon) that has been purified in the reactive distillation system is separately introduced into a reactive distillation tower for reaction, so as to increase the silane gas output of the reactive distillation production process and further reduce the production energy consumption.

[0055] According to the above design ideas, the present invention proposes a system and method for producing high-purity silane by reactive distillation of trichlorosilane, which adopts a treatment process combining multi-stage condensation and distillation tower. The process flow chart is as follows: Figure 1As shown, 1 is the reaction distillation 1# tower; 2 is the reaction distillation 2# tower; 3 is the silane distillation tower; 4 is the reflux tank; 5 is the silane phase separation tank; 6 is the reflux pump; 7 is the silane booster pump; 8 is the first-stage condenser; 9 is the second-stage condenser; 10 is the third-stage condenser; 11 is the fourth-stage heat exchanger; 12 is the fifth-stage condenser; 13 is the silane distillation tower condenser; 14 is the reaction distillation 2# tower condenser; 15 is the reaction distillation 1# tower reboiler; 16 is the silane distillation tower reboiler; 17 is the reaction distillation 2# tower reboiler.

[0056] like Figure 1 As shown, the technical solution proposed by the present invention specifically includes the following steps:

[0057] Step 1: Trichlorosilane (TCS) enters reactive distillation tower 1#, undergoes disproportionation reaction, distillation and purification, and crude silane is obtained at the top of the tower, and high-purity liquid silicon tetrachloride STC is extracted at the bottom of the tower.

[0058] Step 2: The crude silane obtained at the top of the reactive distillation tower 1# passes through a primary condenser 8, a secondary condenser 9, and a tertiary condenser 10 in sequence, wherein the condensate from the primary condenser 8 enters the reflux tank 4 and is pressurized by a reflux pump 6 before entering the top of the reactive distillation tower 1# as tower reflux, and the condensates from the secondary condenser 9 and the tertiary condenser 10 reflux to the middle position of the reactive distillation tower 1# to continue to undergo disproportionation reaction, and the condensed gas is the crude silane in the gas phase.

[0059] The gaseous crude silane condensed in step 3 and step 2 enters the fourth-stage heat exchanger 11. The fourth-stage heat exchanger 11 uses the liquid crude silane condensed by the fifth-stage condenser 12 as a cold source for heat exchange. The crude silane after heat exchange in the fourth-stage heat exchanger 11 enters the fifth-stage condenser 12 for condensation to obtain liquid crude silane.

[0060] The liquid crude silane obtained by the five-stage condenser 12 in step 4 and step 3 enters the silane phase separation tank 5 and enters the silane booster pump 7 to be pressurized and enter the silane distillation tower 3 for distillation. The gas phase part at the top of the tower is condensed into the reflux of the liquid silane distillation tower 3 by the silane distillation tower condenser 13, and a small amount of uncondensed part is discharged from the top of the tower as a gas phase impurity. A mixture of trichlorosilane TCS, dichlorodisilane DCS and monochlorotrisilane MCS is produced from the bottom of the tower. The rest of the materials in the tower kettle are heated by the silane distillation tower reboiler 16 and returned to the silane distillation tower 3 to provide heat for the tower. The side line of the silane distillation tower 3 produces high-purity silane, and its silane content is ≥99.9999%.

[0061] In step 5 and step 4, part of the trichlorosilane TCS, dichlorodisilane DCS, and monochlorotrisilane MCS mixture extracted from the bottom of the silane distillation tower 3 enters the middle position of the reactive distillation tower 2# for another disproportionation reaction, the gaseous crude silane extracted from the top of the reactive distillation tower 2# and condensed by the reactive distillation tower 2# condenser 14 is mixed with the top of the reactive distillation tower 1# for condensation and purification to obtain silane gas, which is condensed into liquid chlorosilane material by the reactive distillation tower 2# condenser 14, and returned to the reactive distillation tower 2# as the top reflux, and part of the trichlorosilane TCS and dichlorodisilane DCS mixture is extracted from the bottom of the tower, enters the middle position of the reactive distillation tower 1# for cyclic disproportionation reaction, and the remaining part of the material in the tower kettle is heated by the reactive distillation tower 2# reboiler 17 and returned to the reactive distillation tower 2# to provide heat for the tower.

[0062] Step 6, reactive distillation 1# tower 1 is composed of a catalyst packing section, a rectifying section and a stripping section, TCS disproportionation reaction is carried out in the catalyst packing section in the tower, the stripping section in the tower purifies silicon tetrachloride STC, and the tower kettle obtains high-purity liquid silicon tetrachloride STC, part of which is extracted from the system, and part of which is heated by the reactive distillation 1# tower reboiler 15 and returned to the reactive distillation 2# tower 1 to provide heat for the tower; the rectifying section in the tower preliminarily purifies silane, and the top of the tower obtains a gas phase silane mixture containing trichlorosilane TCS, dichlorodisilane DCS, monochlorotrisilane MCS and silane, i.e., crude silane. The pressure in reactive distillation 1# tower 1 is 0.1Mpa(G)-0.4Mpa(G), and the temperature of the catalyst packing section is 20°C to 150°C.

[0063] In a specific embodiment, the primary condenser 8 preferably uses circulating water as a cold source, and the inlet temperature of the primary condenser is 30°C to 100°C, and the outlet temperature is 20°C to 60°C.

[0064] In a specific embodiment, the reflux tank 4 stores the mixture condensed by the primary condenser, which contains trichlorosilane TCS, dichlorodisilane DCS and monochlorotrisilane MCS, and the temperature is 20°C to 60°C.

[0065] In a specific embodiment, the reflux pump 6 is preferably a magnetic pump or a shielded pump, which pressurizes the liquid chlorosilane mixture obtained from the reflux tank 4 to 0.3 MPa (G) to 2.0 MPa (G).

[0066] In a specific embodiment, the secondary condenser 9 preferably uses ethylene glycol aqueous solution as a cold source, and the inlet temperature of the secondary condenser is 20°C to 60°C, and the outlet temperature is -20°C to 0°C.

[0067] In a specific embodiment, the three-stage condenser 10 preferably uses Freon as a cold source, and the inlet temperature of the three-stage condenser is -20°C to 0°C, and the outlet temperature is -30°C to -60°C.

[0068] In a specific embodiment, the four-stage heat exchanger 11 uses the crude silane condensed by the five-stage condenser 12 as a cold source for heat exchange. The inlet temperature of the hot flow medium of the four-stage heat exchanger is -30°C to -60°C, and the outlet temperature is -40°C to -70°C. The crude silane after heat exchange in the four-stage heat exchanger contains trichlorosilane TCS, dichlorodisilane DCS, monochlorotrisilane MCS and silane MS.

[0069] In a specific embodiment, the cold source of the five-stage condenser 12 is preferably one of ethylene, R23, and liquid nitrogen. The inlet temperature of the five-stage condenser is -40°C to -70°C, and the outlet temperature is -70°C to -120°C.

[0070] In a specific embodiment, the silane phase separation tank 5 stores the liquid phase crude silane condensed by the five-stage condenser 12 at a temperature of -70°C to -120°C.

[0071] In a specific embodiment, the silane booster pump 7 is preferably a magnetic pump or a shielded pump, which increases the pressure of the liquid crude silane stored in the silane phase separation tank to 0.6 MPa (G) to 5.0 MPa (G).

[0072] In a specific embodiment, the tower pressure of the silane distillation tower 3 is 0.5 MPa(G)-4.0 MPa(G), and the tower top temperature is -20°C to -80°C.

[0073] In a specific embodiment, the temperature of the silane distillation tower condenser 13 is -30°C to -90°C, and gaseous impurities are discharged from the top of the tower.

[0074] In a specific embodiment, the bottom temperature of the silane distillation tower 3 is 20° C. to 80° C., and a mixture of trichlorosilane TCS, dichlorodisilane DCS and monochlorotrisilane MCS is produced at the bottom of the tower.

[0075] In a specific embodiment, the reactive distillation 2# tower 2 is composed of a catalyst packing section, a distillation section and a stripping section. The TCS disproportionation reaction is carried out in the catalyst packing section in the tower. The stripping section in the tower purifies trichlorosilane TCS, and the tower bottom obtains a mixture containing trichlorosilane TCS and dichlorodisilane DCS; the distillation section in the tower preliminarily purifies silane, and the top of the tower obtains a gas phase silane mixture containing dichlorodisilane DCS, monochlorotrisilane MCS and silane, i.e., crude silane. The pressure of the reactive distillation 2# tower 2 is 1.5Mpa(G)-0.6Mpa(G), and the temperature of the catalyst packing section is 20°C to 150°C.

[0076] In a specific embodiment, the condenser 14 of the reactive distillation tower 2 preferably uses circulating water as a cooling source, and the inlet temperature of the condenser 14 of the reactive distillation tower 2 is 30°C to 100°C, and the outlet temperature is 20°C to 60°C.

[0077] In a specific embodiment, the reboiler 15 of the reactive distillation tower #1 preferably uses steam as the heat source.

[0078] In a specific embodiment, the silane distillation column reboiler 16 preferably uses steam as a heat source.

[0079] In a specific embodiment, the reboiler 17 of reactive distillation tower 2# preferably uses steam as the heat source.

[0080] The present invention increases the silane gas production capacity of the existing silane reaction system (increases 10% based on the existing silane gas production) by adding a reactive distillation tower, and further reduces the production energy consumption of the system (steam unit consumption is reduced by 0.82t / t.SiH4).

[0081] In a specific implementation, the present application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium can store a computer program, and when the computer program is executed by the data processing unit, the invention content of a silane gas production system and method based on a double reaction distillation tower provided by the present invention and some or all steps in each embodiment can be run. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0082] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present invention can be implemented by means of computer programs and their corresponding general hardware platforms. Based on such an understanding, the technical solutions in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of computer programs, i.e., software products, which can be stored in a storage medium and include several instructions for enabling a device including a data processing unit (which can be a personal computer, a server, a single-chip microcomputer, an MCU or a network device, etc.) to execute the methods described in various embodiments of the present invention or certain parts of the embodiments.

[0083] The present invention provides a system and method for producing silane gas based on a double reaction distillation tower. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A silane gas production system based on a double reactive distillation tower, characterized in that: The system comprises: A second reaction distillation tower (2) is arranged in the silane gas production system, wherein the middle input end of the second reaction distillation tower (2) is connected to the bottom output end of the silane distillation tower (3) in the silane gas production system, receives the intermediate mixture outputted therefrom and performs a disproportionation reaction; The top output end of the second reaction distillation tower (2) is connected to the top output end of the first reaction distillation tower (1) in the silane gas production system, and the substances therein are mixed and then subsequently processed; The bottom output end of the second reaction distillation tower (2) is connected to the middle input end of the first reaction distillation tower (1) in the silane gas production system, and the substances outputted therefrom are subjected to a disproportionation reaction.

2. A silane gas production system based on a double reaction distillation tower according to claim 1, characterized in that: The silane gas production system comprises: The middle input end of the first reaction distillation tower (1) is used to receive trichlorosilane TCS transmitted by the upstream system and perform a disproportionation reaction; the bottom output end of the first reaction distillation tower (1) outputs liquid silicon tetrachloride STC produced by the reaction; The top output end of the first reaction distillation tower (1) is connected to the input end of the cooling and heat exchange system, and the crude silane produced by the reaction is cooled and heat exchanged to obtain liquid crude silane; A first reaction distillation tower reboiler (15) is also provided at the bottom of the first reaction distillation tower (1) for providing heat thereto; The output end of the cooling and heat exchange system is connected to the input end of a silane distillation tower (3). The silane distillation tower (3) is used to distill the liquid crude silane input thereto. A silane distillation tower condenser (13) is provided at the top of the silane distillation tower (3). The gas phase portion at the top of the silane distillation tower (3) is condensed into a liquid phase through the silane distillation tower condenser (13) and serves as the reflux of the silane distillation tower (3). The uncondensed portion is discharged as a gas phase impurity. The side line output end of the silane distillation tower (3) outputs silane. The bottom output end of the silane distillation tower (3) outputs the intermediate mixture. The bottom of the silane distillation tower (3) is provided with a silane distillation tower reboiler (16) for providing heat therefor.

3. A silane gas production system based on a double reaction distillation tower according to claim 2, characterized in that: The cooling and heat exchange system comprises: A primary condenser (8), a secondary condenser (9), a tertiary condenser (10), a fourth-stage heat exchanger (11) and a fifth-stage condenser (12) connected in sequence; The condensate pipeline of the primary condenser (8) is connected to a reflux tank (4), the reflux tank (4) is used to store the condensate of the primary condenser (8), the reflux tank (4) is connected to the top input end of the first reactive distillation tower (1) via a reflux pump (6), and the reflux pump (6) is used to pressurize the condensate; The condensate pipelines of the secondary condenser (9) and the tertiary condenser (10) are connected to the middle input end of the first reactive distillation tower (1), and the condensate is used to continue the disproportionation reaction; The fourth-stage heat exchanger (11) uses the liquid crude silane condensed in the fifth-stage condenser (12) as a cold source for heat exchange.

4. A silane gas production system based on a double reactive distillation tower according to claim 3, characterized in that: The cooling and heat exchange system further comprises: The silane phase separation tank (5) connected to the output end of the five-stage condenser (12) is used to store the liquid crude silane. The output end of the silane phase separation tank (5) is connected to a silane booster pump (7) for pressurizing the liquid crude silane and inputting it into a downstream device.

5. A silane gas production system based on a double reaction distillation tower according to claim 1, characterized in that: The intermediate mixture is a mixture of trichlorosilane TCS, dichlorodisilane DCS and monochlorotrisilane MCS.

6. A silane gas production system based on double reactive distillation towers according to claim 1, characterized in that: The first reactive distillation tower (1) comprises: A first catalyst packing section, a first rectifying section and a first stripping section, wherein the first catalyst packing section is used for carrying out trichlorosilane TCS disproportionation reaction, the first stripping section is used for purifying silicon tetrachloride STC, and the first rectifying section is used for preliminary purification of silane; The first reactive distillation tower (1) obtains liquid silicon tetrachloride STC in the tower bottom, and obtains a gaseous silane mixture containing trichlorosilane TCS, dichlorodisilane DCS, monochlorotrisilane MCS and silane, i.e., crude silane, at the tower top; The pressure in the first reaction distillation tower (1) is set to 0.1 MPa (G)-0.4 MPa (G), and the temperature of the first catalyst packing section is set to 20°C to 150°C.

7. A silane gas production system based on double reactive distillation towers according to claim 1, characterized in that: The second reactive distillation tower (2) comprises: A second catalyst packing section, a second rectifying section and a second stripping section, wherein the second catalyst packing section is used for carrying out trichlorosilane TCS disproportionation reaction, the second stripping section is used for carrying out trichlorosilane TCS purification, and the second rectifying section is used for preliminary purification of silane; A mixture containing trichlorosilane (TCS) and dichlorodisilane (DCS) is obtained in the kettle of the second reaction distillation tower (2), and a second reaction distillation tower condenser (14) is provided at the top of the tower to condense and obtain a gaseous silane mixture containing dichlorodisilane (DCS), monochlorotrisilane (MCS) and silane, i.e., crude silane; The crude silane is condensed again into a liquid chlorosilane material via the second reaction distillation tower condenser (14), and returned to the second reaction distillation tower (2) as a tower top reflux; The second reaction distillation tower (2) further comprises a second reaction distillation tower reboiler (17) for providing heat for the second reaction distillation tower (2); The pressure in the second reaction distillation tower (2) is set to 1.5 MPa (G) - 0.6 MPa (G), and the temperature of the second catalyst packing section is set to 20°C to 150°C.

8. A silane gas production system based on double reactive distillation towers according to claim 4, characterized in that: The inlet temperature of the primary condenser (8) is set to 30°C to 100°C, and the outlet temperature is set to 20°C to 60°C; The inlet temperature of the secondary condenser (9) is set to 20°C to 60°C, and the outlet temperature is set to -20°C to 0°C; The inlet temperature of the three-stage condenser (10) is set to -20°C to 0°C, and the outlet temperature is set to -30°C to -60°C; The inlet temperature of the heat flow medium in the four-stage heat exchanger (11) is set to -30°C to -60°C, and the outlet temperature is set to -40°C to -70°C; The inlet temperature of the five-stage condenser (12) is set to -40°C to -70°C, and the outlet temperature is set to -70°C to -120°C; The reflux pump (6) is a magnetic pump or a shielded pump, used to increase the pressure to 0.3MPa(G) to 2.0MPa(G); The silane booster pump (7) is a magnetic pump or a shielded pump, which is used to increase the pressure to 0.6 MPa (G) to 5.0 MPa (G).

9. A silane gas production system based on double reactive distillation towers according to claim 2, characterized in that: The tower pressure of the silane distillation tower (3) is set to 0.5MPa(G)-4.0MPa(G), the tower top temperature is set to -20°C to -80°C; and the tower bottom temperature is set to 20°C to 80°C.

10. A method for producing silane gas based on a double reactive distillation tower, characterized in that: The method is implemented by using any system described in claims 1 to 9, comprising: Step 1, setting the second reaction distillation tower (2) in the silane gas production system; Step 2, the middle input end of the first reaction distillation tower (1) in the silane gas production system receives trichlorosilane TCS transmitted by the upstream system, performs a disproportionation reaction, and outputs the liquid phase silicon tetrachloride STC produced by the reaction through its bottom output end; Step 3, the top output end of the second reaction distillation tower (2) is connected to the top output end of the first reaction distillation tower (1), the gases outputted from the two are mixed and then transmitted to the cooling and heat exchange system in the silane gas production system, and liquid crude silane is obtained after cooling and heat exchange; the bottom output end of the second reaction distillation tower (2) is connected to the middle input end of the first reaction distillation tower (1), and the substance outputted from the bottom of the second reaction distillation tower (2) is subjected to a disproportionation reaction; Step 4, transferring the liquid crude silane obtained by the cooling and heat exchange system to a silane distillation tower (3) for distillation, discharging gaseous impurities after distillation from the top output end of the silane distillation tower (3), outputting silane from the side line output end, and transferring the intermediate mixture from the bottom output end to the middle of the second reaction distillation tower (2) for disproportionation reaction.

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