Silane gas production system and method

Abstract

The invention belongs to the technical field of chemical engineering, and particularly relates to a silane gas production system and method.The silane gas production system comprises three reactors, a reaction tower, a condensation system and a silane storage tank, the three reactors are provided with inlets and outlets respectively, and the reaction tower is provided with a first inlet, a second inlet and a third inlet; an inlet of the first reactor is connected with a raw material input pipeline, an outlet of the first reactor is connected with a first inlet of the reaction tower, an outlet of the second reactor is connected with a second inlet of the reaction tower, an outlet of the third reactor is connected with a third inlet of the reaction tower, and a tower top outlet of the reaction tower is connected with a gas phase inlet of the condensation system. Inlets of the second reactor and the third reactor and an inlet of the silane storage tank are respectively connected with corresponding liquid phase outlets of the condensation system. According to the method, the material utilization rate can be further improved, and the conversion rate and the yield of chlorosilane are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a silane gas production system and method. Background Art

[0002] Solar photovoltaic power generation is an efficient, environmentally friendly and clean new energy technology. As a key material in the fields of integrated circuits, photovoltaic power generation, etc., the cost and quality of polysilicon play an important role in the development of the photovoltaic industry.

[0003] Compared with the traditional polysilicon production method, granular silicon produced by silane fluidized bed method has competitive advantages such as energy saving, environmental protection and high efficiency. Silane is the main intermediate product of polysilicon production by silane fluidized bed method. Its production cost and efficiency directly affect the production cost of granular silicon. Only by continuously optimizing the silane production process and improving product quality can the photovoltaic industry achieve long-term sustainable development.

[0004] Therefore, there is a need to develop a new silane production system and method. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a silane gas production system and method, which can achieve multiple stage-by-stage separation of chlorosilane and silane, and the unreacted chlorosilane material can re-enter the reactor for reaction. The closed-loop design can achieve complete conversion of the chlorosilane raw material, and there is almost no material loss in the vented tail gas, which has the advantages of high efficiency, cleanliness and environmental protection.

[0006] The technical solution provided by the present invention is as follows: The present invention provides a silane gas production system, comprising three reactors, a reaction tower, a condensation system and a silane storage tank, wherein the three reactors are respectively provided with an inlet and an outlet, the reaction tower is provided with a first inlet, a second inlet and a third inlet, the inlet of the first reactor is connected to a raw material input pipeline, the outlet of the first reactor is connected to the first inlet of the reaction tower, the outlet of the second reactor is connected to the second inlet of the reaction tower, the outlet of the third reactor is connected to the third inlet of the reaction tower, the tower top outlet of the reaction tower is connected to the gas phase inlet of the condensation system, and the inlets of the second reactor, the third reactor and the inlet of the silane storage tank are respectively connected to the corresponding liquid phase outlets of the condensation system.

[0007] The present invention also provides a silane gas production method, based on the above-mentioned silane gas production system, comprising the following steps: S1: trichlorosilane is fed into the first reactor through the first pressure pump for the first disproportionation reaction, and the obtained product is then fed into the reaction tower for separation of light and heavy components, crude silane is obtained at the top of the tower, and tetrachlorosilane is produced at the bottom of the tower; S2: The crude silane obtained from the top of the reaction tower enters the condensation system, and dichlorosilane and trichlorosilane are condensed and refluxed and enter the second reactor through the second pressure pump for a second disproportionation reaction. The obtained product then enters the reaction tower for separation of light and heavy components; S3: the uncondensed monochlorosilane and silane in step S2 continue to be condensed in the condensation system, and the condensed monochlorosilane is refluxed to the third reactor for a third disproportionation reaction, and the obtained product then enters the reaction tower for separation of light and heavy components; S4: the uncondensed silane in step S3 continues to be condensed in the condensation system, and the silane enters the silane storage tank after being condensed, and the uncondensed non-condensable gas is discharged as tail gas.

[0008] Further, the condensation system includes three-stage series condensers, including a primary condenser, a secondary condenser and a tertiary condenser; The primary condenser is used to condense the crude silane obtained from the top of the reaction tower in step S2, the secondary condenser is used to condense the uncondensed monochlorosilane and silane in step S3, and the tertiary condenser is used to condense the uncondensed silane in step S4.

[0009] Furthermore, the operation of entering the product obtained after the third disproportionation reaction in the third reaction container into the reaction tower in step S3 also includes: passing the dichlorosilane and silane obtained by the third disproportionation reaction into the stripping tower for separation, the separated dichlorosilane is taken out from the bottom of the tower and enters the reaction tower for light and heavy component separation, the separated silane enters the third-stage condenser from the top of the tower for condensation, and the silane enters the silane storage tank after condensation.

[0010] Furthermore, the cold source in the primary condenser is ethylene glycol, the inlet temperature of the primary condenser is 0-50°C, and the outlet temperature is -20-10°C.

[0011] Furthermore, the cold source in the secondary condenser is Freon, the inlet temperature of the primary condenser is -20~10°C, and the outlet temperature is -60~-10°C.

[0012] Furthermore, the cold source in the three-stage condenser is liquid nitrogen, the inlet temperature of the first-stage condenser is -90~-40°C, and the outlet temperature is -120~-60°C.

[0013] Furthermore, the tower pressure of the reaction tower is 0.15-0.45 MPa, the tower top temperature is 20-80°C, and the tower bottom temperature is 95-155°C.

[0014] Furthermore, the stripping tower has a tower pressure of 0.15-0.45 MPa, a tower top temperature of 20-80°C, and a tower bottom temperature of 30-100°C.

[0015] Furthermore, the first pressure pump is used to increase the pressure of trichlorosilane to 0.5-1.6 Mpa, and the second pressure pump is used to increase the pressure of trichlorosilane and dichlorosilane obtained by condensation in the primary condenser to 0.5-1.6 Mpa. Beneficial Effects

[0016] The present invention is applied to the production of silane gas by disproportionation reaction of chlorosilane, and the closed-loop circulation of chlorosilane is completely converted into silane gas through a reaction tower, a reactor, a stripping tower, a multi-stage condenser, etc. Compared with the original process, the present process can realize multiple stage-by-stage separation of chlorosilane and silane, and the unreacted chlorosilane material can re-enter the reactor for reaction. The closed-loop design can realize the complete conversion of the chlorosilane raw material, and there is almost no material loss in the vented tail gas. Therefore, the present invention has the advantages of high efficiency, cleanliness, and environmental protection.

[0017] The method of the present invention rationally utilizes the cold source and utilizes a multi-stage condensation system to perform multiple condensation heat exchanges. The quality of the cold source is gradually increased, the flow of the cooled crude silane is gradually reduced, and the purity is gradually increased, so that the power of the high-quality cold source at a low temperature reaches a minimum value, and the energy utilization rate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a silane gas production system of the present invention.

[0019] Explanation of the reference numerals: 1. first reactor; 2. second reactor; 3. third reactor; 4. primary condenser; 5. secondary condenser; 6. tertiary condenser; 7. reflux tank; 8. stripping tower; 9. silane storage tank; 10. reaction tower; 11. first boosting pump; 12. second boosting pump; 13. reboiler. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the embodiments. Example 1

[0021] like Figure 1 As shown, an embodiment of the present invention provides a silane gas production system, comprising a reaction tower 10, a stripping tower 8, three reactors and two pressure pumps.

[0022] In this embodiment, the three reactors are respectively provided with an inlet and an outlet, and the reaction tower 10 is provided with a first inlet, a second inlet and a third inlet, the inlet of the first reactor 1 is connected to the raw material input pipeline, the outlet of the first reactor 1 is connected to the first inlet of the reaction tower 10, the outlet of the second reactor 2 is connected to the second inlet of the reaction tower 10, and the outlet of the third reactor 3 is connected to the third inlet of the reaction tower 10. The top outlet of the reaction tower 10 is connected to the gas phase inlet of the condensation system, and the inlets of the second reactor 2, the third reactor 3 and the inlet of the silane storage tank 9 are respectively connected to the corresponding liquid phase outlets of the condensation system.

[0023] By adopting the above technical scheme, chlorosilane and silane can be separated step by step and multiple times, and the unreacted chlorosilane material can re-enter the reactor for reaction. The closed-loop design can achieve complete conversion of the chlorosilane raw material.

[0024] In this embodiment, the condensation system includes three-stage series condensers, including a first-stage condenser 4, a second-stage condenser 5 and a third-stage condenser 6, the gas phase inlet of the first-stage condenser 4 is connected to the top outlet of the reaction tower 10, the liquid phase outlet of the first-stage condenser 4 is connected to the inlet of the second reactor 2, the liquid phase outlet of the second condenser 5 is connected to the inlet of the third reactor 3, and the liquid phase outlet of the third-stage condenser 6 is connected to the silane storage tank 9.

[0025] In this embodiment, a stripping tower 8 is arranged between the outlet of the third reactor 3 and the third inlet of the reaction tower 10, the top outlet of the stripping tower 8 is connected to the gas phase inlet of the third-stage condenser 6, and a reboiler 13 is arranged at the bottom of the stripping tower 8.

[0026] By adopting the above technical solution, the light component impurities contained in silane can be further removed, and the composition of the raw materials entering the reaction tower 10 can be flexibly adjusted, so as to better control the purity and yield of silane.

[0027] In this embodiment, a reflux tank 7 is provided between the liquid phase outlet of the primary condenser and the second reaction container.

[0028] In this embodiment, the raw material input pipeline is provided with a first pressure pump 11, and a second pressure pump 12 is provided between the outlet of the reflux tank 7 and the second reaction container.

[0029] In this embodiment, the first pressure pump 11 and the second pressure pump 12 are selected from one or more of a shielded pump and a magnetic pump.

[0030] In this embodiment, the first reactor 1 , the second reactor 2 and the third reactor 3 are all filled with resin catalyst.

[0031] In this embodiment, the stripping tower 8 is a packed tower or a plate tower.

[0032] It should be noted that, in the present embodiment, the reaction tower 10 is used for separating and purifying the light components and heavy components in the chlorosilane mixture; the first reactor 1 is mainly used for the trichlorosilane disproportionation reaction process; the second reactor 2 is mainly used for the trichlorosilane disproportionation reaction and the dichlorosilane disproportionation reaction process; the third reactor 3 is mainly used for the monochlorosilane disproportionation reaction process; the stripping tower 8 is used for separating and purifying the chlorosilane and the silane gas and liquid; the reflux tank 7 is used for storing liquid chlorosilane; the silane storage tank 9 is used for storing liquid silane; the condenser is used for exchanging heat with the material, cooling the gas, and condensing and liquefying it. Example 2

[0033] The embodiment of the present invention provides a silane production method, based on the silane gas production system described in Example 1, comprising the following steps: S1: trichlorosilane is fed into the first reactor 1 through the first pressure pump 11 for the first disproportionation reaction, and the obtained product then enters the reaction tower 10 for separation of light and heavy components, crude silane is obtained at the top of the tower, and tetrachlorosilane is extracted at the bottom of the tower; The crude silane obtained at the top of the S2 reaction tower 10 enters the condensation system, and the dichlorosilane and trichlorosilane are condensed and refluxed and enter the second reaction container 2 through the second pressure pump 12 for the second disproportionation reaction. The obtained product then enters the reaction tower 10 for separation of light and heavy components; S3: The uncondensed monochlorosilane and silane in step S2 continue to be condensed in the condensation system, and the condensed monochlorosilane is refluxed to the third reactor 3 for the third disproportionation reaction, and the obtained product then enters the reaction tower 10 for separation of light and heavy components; S4: The uncondensed silane in step S3 continues to be condensed in the condensation system. After the silane is condensed, it enters the silane storage tank 9, and the uncondensed non-condensable gas is discharged as tail gas.

[0034] Further, the condensation system includes three-stage series condensers, including a primary condenser 4, a secondary condenser 5 and a tertiary condenser 6; The step S2 is more specifically as follows: the crude silane obtained from the top of the reaction tower 10 is passed into the primary condenser 4, dichlorosilane and trichlorosilane are condensed and refluxed, and enter the second reactor 2 through the second pressure pump for a second disproportionation reaction, and the obtained product then enters the reaction tower 10 for separation of light and heavy components; The step S3 is more specifically as follows: uncondensed monochlorosilane and silane continue to be condensed in the secondary condenser 5, and the condensed monochlorosilane is refluxed to the third reactor 3 for a third disproportionation reaction, and the obtained product then enters the reaction tower 10 for separation of light and heavy components; The step S4 is more specifically as follows: the uncondensed silane continues to be condensed in the three-stage condenser 6, and the silane enters the silane storage tank 9 after being condensed, and the uncondensed non-condensable gas is discharged as tail gas.

[0035] Furthermore, the operation of entering the reaction tower 10 with the product obtained after the third disproportionation reaction in the third reactor 3 in step S3 also includes: passing the dichlorosilane and silane obtained in the third disproportionation reaction into the stripping tower 8 for separation, the separated dichlorosilane is taken out from the bottom of the tower and enters the reaction tower 10 for light and heavy component separation, the separated silane enters the third-stage condenser 6 from the top of the tower for condensation, and the silane enters the silane storage tank 9 after condensation.

[0036] Specifically, trichlorosilane of a certain temperature (50-70 degrees Celsius), pressure (0.15-0.25 MPa), and flow rate (less than 150 t / h) is pressurized by the first booster pump 11, and then reacted in the first reactor 1 and then enters the reaction tower 10. In the first reactor 1, trichlorosilane reacts to generate dichlorosilane, silicon tetrachloride, monochlorosilane, silane and other materials. The materials are separated from the light components and heavy components in the reaction tower 10. The gaseous components such as trichlorosilane, dichlorosilane, monochlorosilane, silane and other gaseous components at the top of the reaction tower 10 are condensed by the primary condenser 4 and enter the reflux tank 7. The condensed trichlorosilane, dichlorosilane and other materials are pressurized by the second booster pump 12 and enter the reflux tank 7. The material enters the second reactor 2, and the material reacts again to generate dichlorosilane and monochlorosilane, and then returns to the reaction tower 10; the gaseous materials such as monochlorosilane and silane that are not condensed in the primary condenser 4 enter the secondary condenser 5 for condensation, and the liquid material mainly of monochlorosilane is reacted in the third reactor 3 to generate dichlorosilane and silane, and then enters the stripping tower 8 for gas-liquid separation; the dichlorosilane liquid material in the stripping tower 8 is extracted from the bottom of the tower to the reaction tower 10 for circulation, and the gaseous materials such as silane at the top of the stripping tower 8 and the uncondensed silane in the secondary condenser 5 enter the tertiary condenser 6, and the condensed liquid silane enters the silane storage tank 9, and the uncondensed non-condensable gas is discharged as tail gas.

[0037] In this embodiment, the cold source in the primary condenser 4 is ethylene glycol, the inlet temperature of the primary condenser 4 is 0-50°C, and the outlet temperature is -20-10°C.

[0038] In this embodiment, the cold source in the secondary condenser 5 is Freon, the inlet temperature of the primary condenser 4 is -20~10°C, and the outlet temperature is -60~-10°C.

[0039] In this embodiment, the cold source in the three-stage condenser 6 is liquid nitrogen, the inlet temperature of the first-stage condenser 4 is -90~-40°C, and the outlet temperature is -120~-60°C.

[0040] In this embodiment, the tower pressure of the reaction tower 10 is 0.15-0.45 MPa, the tower top temperature is 20-80° C., and the tower bottom temperature is 95-155° C.

[0041] In this embodiment, the stripping tower 8 has a tower pressure of 0.15-0.45 MPa, a tower top temperature of 20-80° C., and a tower bottom temperature of 30-100° C.

[0042] In this embodiment, the first pressure pump 11 is used to increase the pressure of trichlorosilane to 0.5-1.6 Mpa, and the second pressure pump 12 is used to increase the pressure of trichlorosilane and dichlorosilane obtained by condensation in the primary condenser 4 to 0.5-1.6 Mpa.

[0043] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A silane gas production system, characterized in that: The invention comprises three reactors, a reaction tower, a condensation system and a silane storage tank, wherein the three reactors are respectively provided with an inlet and an outlet, the reaction tower is provided with a first inlet, a second inlet and a third inlet, the inlet of the first reactor is connected to a raw material input pipeline, the outlet of the first reactor is connected to the first inlet of the reaction tower, the outlet of the second reactor is connected to the second inlet of the reaction tower, the outlet of the third reactor is connected to the third inlet of the reaction tower, the top outlet of the reaction tower is connected to the gas phase inlet of the condensation system, and the inlets of the second reactor, the third reactor and the inlet of the silane storage tank are respectively connected to the corresponding liquid phase outlets of the condensation system.

2. A method for producing silane gas, characterized in that: The silane gas production system according to claim 1 comprises the following steps: S1: trichlorosilane is fed into the first reactor through the first pressure pump for the first disproportionation reaction, and the obtained product is then fed into the reaction tower for separation of light and heavy components, crude silane is obtained at the top of the tower, and tetrachlorosilane is produced at the bottom of the tower; S2: The crude silane obtained from the top of the reaction tower enters the condensation system, and dichlorosilane and trichlorosilane are condensed and refluxed and enter the second reactor through the second pressure pump for a second disproportionation reaction. The obtained product then enters the reaction tower for separation of light and heavy components; S3: the uncondensed monochlorosilane and silane in step S2 continue to be condensed in the condensation system, and the condensed monochlorosilane is refluxed to the third reactor for a third disproportionation reaction, and the obtained product then enters the reaction tower for separation of light and heavy components; S4: the uncondensed silane in step S3 continues to be condensed in the condensation system, and the silane enters the silane storage tank after being condensed, and the uncondensed non-condensable gas is discharged as tail gas.

3. The method for producing silane gas according to claim 2, characterized in that: The condensation system comprises three-stage series condensers, including a primary condenser, a secondary condenser and a tertiary condenser; The primary condenser is used to condense the crude silane obtained from the top of the reaction tower in step S2, the secondary condenser is used to condense the uncondensed monochlorosilane and silane in step S3, and the tertiary condenser is used to condense the uncondensed silane in step S4.

4. The method for producing silane gas according to claim 2, characterized in that: The operation of introducing the product obtained after the third disproportionation reaction in the third reaction container into the reaction tower in step S3 also includes: introducing the dichlorosilane and silane obtained in the third disproportionation reaction into the stripping tower for separation, the separated dichlorosilane is taken out from the bottom of the tower and introduced into the reaction tower for light and heavy component separation, the separated silane is introduced into the third-stage condenser from the top of the tower for condensation, and the silane enters the silane storage tank after condensation.

5. The method for producing silane gas according to claim 3, characterized in that: The cold source in the primary condenser is ethylene glycol, the inlet temperature of the primary condenser is 0-50°C, and the outlet temperature is -20-10°C.

6. The method for producing silane gas according to claim 3, characterized in that: The cold source in the secondary condenser is Freon, the inlet temperature of the primary condenser is -20~10℃, and the outlet temperature is -60~-10℃.

7. The method for producing silane gas according to claim 3, characterized in that: The cold source in the three-stage condenser is liquid nitrogen, the inlet temperature of the first-stage condenser is -90~-40°C, and the outlet temperature is -120~-60°C.

8. The method for producing silane gas according to claim 2, characterized in that: The tower pressure of the reaction tower is 0.15-0.45 MPa, the tower top temperature is 20-80°C, and the tower bottom temperature is 95-155°C.

9. The method for producing silane gas according to claim 4, characterized in that: The stripping tower has a tower pressure of 0.15-0.45 MPa, a tower top temperature of 20-80°C, and a tower bottom temperature of 30-100°C.

10. The method for producing silane gas according to claim 2, characterized in that: The first pressure pump is used to increase the pressure of trichlorosilane to 0.5-1.6 MPa, and the second pressure pump is used to increase the pressure of trichlorosilane and dichlorosilane obtained by condensation in the primary condenser to 0.5-1.6 MPa.

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