Oxygen-containing chlorosilane waste material recycling device

Abstract

The utility model discloses an oxychlorosilane waste recycling device which is used for removing metal chloride and solid particles in oxychlorosilane waste liquid so as to prevent equipment or pipelines from being blocked, recycling valuable elements such as silicon and chlorine from the oxychlorosilane waste and reducing the operation cost in the polycrystalline silicon production process. The device comprises a scraper evaporator (2), a heavy component removal tower (3), a vaporizer (9), a chlorination furnace (10), a cooling assembly (27) and a separation assembly (28). A feeding hole of the scraper evaporator (2) is used for receiving oxychlorosilane waste liquid, and the bottom of a tower kettle of the scraper evaporator (2) is communicated with a hydrolysis device. A feeding hole of the chlorination furnace (10) is communicated with a discharging hole of the vaporizer (9), and the chlorination furnace (10) is also respectively communicated with a carbon reducing agent material pipe and a chlorine gas material pipe. A feeding hole of the separating assembly (28) is communicated with a discharging hole of the cooling assembly (27) and is used for separating silicon tetrachloride.

Description

Technical Field

[0001] The utility model belongs to the field of polysilicon production, and specifically relates to a device for recycling oxygen-containing chlorosilane waste. Background Art

[0002] In the process of polysilicon production, a certain amount of by-product waste is produced. This waste is produced by the high-boiling cracking device. In addition to metal chlorides and solid particles, the waste also includes oxygen-containing chlorosilanes, chlorosilane oligomers and a small amount of silicon tetrachloride.

[0003] The working process of the high-boiling cracking unit is to generate trichlorosilane and silicon tetrachloride through the reaction of chlorosilane polymers with hydrogen chloride under the action of catalysts, thereby realizing the recovery and utilization of part of the by-product high-boiling products, but oxygen-containing chlorosilanes and a small amount of chlorosilane oligomers do not participate in the reaction and produce waste.

[0004] Most companies generally use direct hydrolysis to treat this waste, that is, the chlorosilane waste is reacted with water in a special hydrolysis device. The hydrogen chloride gas produced by the hydrolysis is absorbed through leaching and then neutralized with alkaline solution to adjust the pH value to neutral before discharge. The metal chlorides and solid particles are further separated from the solid and liquid through filtration, centrifugation and other means, and the solid matter is directly transported out for landfill or utilization.

[0005] Because the waste contains metal chlorides and solid particles, the material is prone to become sticky or crystalline, which can easily block equipment or pipelines and cause equipment shutdown or damage. Therefore, there is no other good way to deal with the waste, resulting in the waste being treated only by hydrolysis. Due to the rapid development of the polysilicon industry and the continuous expansion of production capacity, the amount of this part of waste is also increasing. The loss of valuable elements such as silicon and chlorine caused by hydrolysis, as well as the increase in wastewater and solid waste generated year-on-year, have increased the operating costs of the polysilicon production process.

[0006] The oxygen-containing chlorosilanes and chlorosilane oligomers contained in the waste cannot be directly recycled and need to be converted and recycled, which is a difficult problem currently encountered by the polysilicon industry. Utility Model Content

[0007] The technical problem to be solved by the utility model is to provide a device for recycling oxygen-containing chlorosilane waste in view of the above-mentioned deficiencies in the prior art, which can remove metal chlorides and solid particles in the oxygen-containing chlorosilane waste liquid to avoid clogging of equipment or pipelines, and recover valuable elements such as silicon and chlorine from the oxygen-containing chlorosilane waste, thereby reducing the operating cost of the polysilicon production process.

[0008] The utility model embodiment provides a device for recycling oxygen-containing chlorosilane waste, which includes a scraper evaporator, a deweighting tower, a vaporizer, a chlorination furnace, a cooling assembly and a separation assembly. The feed port of the scraper evaporator is used to receive oxygen-containing chlorosilane waste liquid, and is used to evaporate and separate the oxygen-containing chlorosilane waste liquid. The bottom of the tower kettle of the scraper evaporator is connected to a hydrolysis device. The feed port of the deweighting tower is connected to the gas phase outlet of the scraper evaporator, and is used to deweight and rectify the evaporated mixed vapor of oxygen-containing chlorosilane, chlorosilane oligomers and silicon tetrachloride. Its gas phase outlet is connected to a silicon tetrachloride storage device, and the gaseous silicon tetrachloride separated from the top of the tower enters the silicon tetrachloride storage device through the gas phase outlet of the deweighting tower for storage. The feed port of the vaporizer is connected to the bottom of the tower kettle of the deweighting tower, and is used to heat and vaporize the mixture of oxygen-containing chlorosilane and chlorosilane oligomers separated from the tower kettle of the deweighting tower. The feed inlet of the chlorination furnace is connected to the discharge port of the vaporizer, and the chlorination furnace is also connected to the carbon reducing agent feed pipe and the chlorine gas feed pipe respectively, and is used to react various materials entering the interior to generate silicon tetrachloride, trichlorosilane and carbon monoxide. The feed inlet of the cooling component is connected to the discharge port of the chlorination furnace, and is used to cool the mixed gas of silicon tetrachloride, trichlorosilane and carbon monoxide passing through the cooling component, and discharge carbon monoxide gas through the exhaust hole on the top of the cooling component. The feed inlet of the separation component is connected to the discharge port of the cooling component, and is used to separate silicon tetrachloride, and its discharge port is connected to the silicon tetrachloride storage device.

[0009] Thus, the oxygen-containing chlorosilane waste recycling device provided by the utility model embodiment can separate metal chlorides and solid particles from oxygen-containing chlorosilane waste by setting a scraper evaporator, so as to avoid the above-mentioned metal chlorides and solid particles blocking the pipelines and equipment in the subsequent process and causing damage. By setting a deweighting tower, silicon tetrachloride can be separated from oxygen-containing chlorosilane waste, and the mixture of oxygen-containing chlorosilane and chlorosilane oligomer remaining in the oxygen-containing chlorosilane waste is transported to a vaporizer, and after evaporation in the vaporizer, it enters a chlorination furnace and reacts with a carbon reducing agent and chlorine to generate silicon tetrachloride, trichlorosilane and carbon monoxide, and then carbon monoxide is discharged in a cooling component. By setting a separation component, silicon tetrachloride can be separated, so as to realize the conversion and recycling of chlorosilane oligomers and oxygen-containing chlorosilane in oxygen-containing chlorosilane waste, reduce the loss of valuable elements such as silicon and chlorine and the waste water and waste solid generated therefrom, and is conducive to reducing the operating cost of the polysilicon production process.

[0010] In some embodiments, the separation component includes a chlorination weight removal tower and a product tower and a product tower. The feed port of the chlorination weight removal tower is connected to the discharge port of the cooling component, and is used to separate unreacted oxygen-containing chlorosilanes and chlorosilane oligomers. The bottom of the tower kettle is connected to the feed port of the vaporizer to transport unreacted oxygen-containing chlorosilanes and chlorosilane oligomers to the vaporizer for vaporization again, and its gas phase outlet is used to output a mixed gas of silicon tetrachloride and trichlorosilane. The feed port of the product tower is connected to the gas phase outlet of the chlorination weight removal tower, and is used to separate silicon tetrachloride from the mixed gas of silicon tetrachloride and trichlorosilane. Its gas phase outlet is connected to a light component storage device, and is used to store the gaseous trichlorosilane separated from the top of the tower in the light component storage device through the gas phase outlet of the product tower. The bottom of the tower kettle is connected to the silicon tetrachloride storage device, and is used to store the silicon tetrachloride separated from the tower kettle in the silicon tetrachloride storage device.

[0011] In some embodiments, the separation component further includes a chlorination de-weighting tower reboiler. The feed port of the chlorination de-weighting tower reboiler is connected to the tower kettle of the chlorination de-weighting tower, and is used to heat up and vaporize the liquid silicon tetrachloride and liquid trichlorosilane in the tower kettle of the chlorination de-weighting tower again; the discharge port of the chlorination de-weighting tower reboiler is connected to the interior of the chlorination de-weighting tower, and is used to transport the heated and vaporized materials back to the interior of the chlorination de-weighting tower.

[0012] In some embodiments, the separation component further includes a product tower reboiler. The feed port of the product tower reboiler is connected to the bottom of the tower kettle of the product tower, so as to heat up and vaporize the liquid phase trichlorosilane in the tower kettle of the product tower again; the discharge port of the product tower reboiler is connected to the interior of the product tower, so as to transport the heated and vaporized material back to the interior of the product tower.

[0013] In some embodiments, the separation component further comprises a chlorination weight removal tower top condenser, a chlorination weight removal tower top reflux tank and a chlorination weight removal tower top reflux pump. The chlorination weight removal tower top condenser, whose feed port is connected to the gas phase outlet of the chlorination weight removal tower, is used to condense the mixed gas of silicon tetrachloride and trichlorosilane into a liquid phase mixture. The chlorination weight removal tower top reflux tank, whose feed port is connected to the discharge port of the chlorination weight removal tower top condenser, is used to temporarily store the liquid phase mixture of silicon tetrachloride and trichlorosilane. The chlorination weight removal tower top reflux pump, whose feed port is connected to the discharge port of the chlorination weight removal tower top reflux tank, and whose discharge port is respectively connected to the inside of the chlorination weight removal tower and the feed port of the product tower, is used to transport a portion of the liquid phase mixture of silicon tetrachloride and trichlorosilane to the inside of the chlorination weight removal tower, and transport another portion of the liquid phase mixture of silicon tetrachloride and trichlorosilane to the product tower.

[0014] In some embodiments, the separation component further includes a product tower top condenser, a product tower top reflux tank, and a product tower top reflux pump. The feed port of the product tower top condenser is connected to the gas phase outlet of the product tower, and is used to condense gaseous trichlorosilane into liquid trichlorosilane. The feed port of the product tower top reflux tank is connected to the discharge port of the product tower top condenser, and is used to temporarily store liquid trichlorosilane. The feed port of the product tower top reflux pump is connected to the discharge port of the product tower top reflux tank, and its discharge port is connected to the interior of the product tower and the light component storage device, respectively, and is used to transport a portion of liquid trichlorosilane to the interior of the product tower, and another portion of liquid trichlorosilane to the light component storage device.

[0015] In some embodiments, a filter is further provided between the gas phase outlet of the chlorination furnace and the feed inlet of the cooling assembly for filtering the carbon reducing agent.

[0016] In some embodiments, a silicon tetrachloride buffer tank is provided between the discharge port of the cooling component and the feed port of the separation component for temporarily storing the material entering the tank; an exhaust hole is provided at the top of the silicon tetrachloride buffer tank for further discharging carbon monoxide.

[0017] In some embodiments, a deweighting tower reboiler is provided outside the deweighting tower, and the feed port of the deweighting tower reboiler is connected to the bottom of the deweighting tower, so as to heat up and vaporize the material in the bottom of the deweighting tower again; the discharge port of the deweighting tower reboiler is connected to the interior of the deweighting tower, so as to transport the heated and vaporized material back to the interior of the deweighting tower.

[0018] In some embodiments, a weight removal tower top condenser, a weight removal tower top reflux tank and a weight removal tower top reflux pump are also provided between the gas phase outlet of the weight removal tower and the silicon tetrachloride storage device. The feed port of the weight removal tower top condenser is connected to the gas phase outlet of the weight removal tower, and is used to condense gaseous silicon tetrachloride into liquid silicon tetrachloride. The feed port of the weight removal tower top reflux tank is connected to the discharge port of the weight removal tower top condenser, and is used to temporarily store liquid silicon tetrachloride. The feed port of the weight removal tower top reflux pump is connected to the discharge port of the weight removal tower top reflux tank, and the discharge port of the weight removal tower top reflux pump is connected to the inside of the weight removal tower and the silicon tetrachloride storage device, respectively, for transporting a portion of liquid silicon tetrachloride to the inside of the weight removal tower, and another portion of liquid silicon tetrachloride to the silicon tetrachloride storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : A structural diagram of an oxygen-containing chlorosilane waste recycling device provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] Embodiment 1:

[0022] like Figure 1 As shown, an embodiment of the utility model provides an oxygen-containing chlorosilane waste recycling device for recovering oxygen-containing chlorosilane and a small amount of chlorosilane oligomers in the polysilicon production process. The device includes a scraper evaporator 2, a deweighting tower 3, a vaporizer 9, a chlorination furnace 10, a cooling component 27 and a separation component 28.

[0023] For example, Figure 1 As shown, the recycling device also includes an oxygen-containing chlorosilane waste buffer tank 1. The feed port of the scraper evaporator 2 is connected to the oxygen-containing chlorosilane waste buffer tank 1. The oxygen-containing chlorosilane waste generated during the production of polysilicon first enters the oxygen-containing chlorosilane waste buffer tank 1 for temporary storage, and then is transported to the scraper evaporator 2.

[0024] like Figure 1 As shown, the feed port of the scraper evaporator 2 is used to receive the oxygen-containing chlorosilane waste liquid temporarily stored in the oxygen-containing chlorosilane waste buffer tank 1, and evaporate and separate the oxygen-containing chlorosilane waste liquid. The bottom of the tower kettle of the scraper evaporator 2 is connected to the hydrolysis device.

[0025] Exemplarily, the operating temperature of the scraper evaporator 2 is controlled between 150°C and 170°C.

[0026] The oxygen-containing chlorosilane feed liquid is added from the upper part of the scraper evaporator 2 along the tangential direction. Under the action of gravity and the rotating scraper, the oxygen-containing chlorosilane feed liquid forms a downward rotating film along the inner wall of the scraper evaporator 2. Chlorosilane oligomers and oxygen-containing chlorosilane in the oxygen-containing chlorosilane feed liquid are continuously heated and evaporated during the descending process, and the steam escapes from the gas phase outlet at the top of the scraper evaporator 2. The high-boiling point metal chloride and solid particles adhere to the inner wall of the scraper evaporator 2, and are then pushed to the bottom of the scraper evaporator 2 by the rotating scraper and discharged to the hydrolysis device A for hydrolysis.

[0027] like Figure 1 As shown, the feed port of the deweighting tower 3 is connected to the gas phase outlet of the scraper evaporator 2, which is used for deweighting and distilling the evaporated mixed vapor of oxygen-containing chlorosilane, chlorosilane oligomers and silicon tetrachloride, and its gas phase outlet is connected to the silicon tetrachloride storage device B, and the gaseous silicon tetrachloride separated from the top of the tower enters the silicon tetrachloride storage device B through the gas phase outlet of the deweighting tower 3 for storage.

[0028] The steam escaping from the top of the scraper evaporator 2 enters the deweighting tower 3 from the middle and lower part of the deweighting tower 3. 4-10 sections of packing are arranged in the deweighting tower 3. The operating pressure of the deweighting tower 3 is set between 60KPaG-80KPaG, the operating temperature of the tower top is set between 62℃-82℃, the reflux ratio of the tower top is set to 3-12, and the operating temperature of the tower bottom is set between 73℃-93℃.

[0029] like Figure 1 As shown, the feed port of the vaporizer 9 is connected to the bottom of the kettle of the deweighting tower 3, and is used to heat and vaporize the mixture of oxygen-containing chlorosilane and chlorosilane oligomer separated from the kettle of the deweighting tower 3.

[0030] The vaporizer 9 adopts a kettle reboiler structure, and the vaporized mixed steam of oxygen-containing chlorosilane and chlorosilane oligomers escapes from the top of the heating kettle. The temperature of the vaporized mixed steam of oxygen-containing chlorosilane and chlorosilane oligomers is between 90°C and 155°C.

[0031] like Figure 1 As shown, the feed port of the chlorination furnace 10 is connected to the discharge port of the vaporizer 9, and the chlorination furnace 10 is also connected to the carbon reducing agent material pipe and the chlorine gas material pipe respectively, so as to react various materials entering the interior thereof to generate silicon tetrachloride, trichlorosilane and carbon monoxide.

[0032] Exemplarily, the carbon reducing agent feed pipe is used to transport the carbon (C) reducing agent to the chlorination furnace 10 for reaction, and the chlorine gas feed pipe is used to transport the chlorine gas (Cl2) to the chlorination furnace 10 for reaction.

[0033] The material steam and chlorine gas discharged from the discharge port of the vaporizer 9 enter the chlorination furnace 10 from the bottom of the chlorination furnace 10, and the carbon reducing agent enters the chlorination furnace 10 from the top of the chlorination furnace 10 and reacts in the chlorination furnace 10. The reaction temperature is between 480° C. and 520° C. The main reactions involved in the chlorination furnace 10 are:

[0034] Cl6OSi2+C+Cl2→2SiCl4+CO;

[0035] 2Cl5OSi2+2C+3Cl2→4SiCl4+2CO;

[0036] Si x Cl y +Cl2→SiCl4.

[0037] Among them, x and y are positive integers.

[0038] The mixed gas of silicon tetrachloride, trichlorosilane and carbon monoxide produced after the reaction is discharged from the top of the chlorination furnace 10, and the temperature of the mixed gas is between 500°C and 650°C.

[0039] It is understandable that the mixed gas of silicon tetrachloride, trichlorosilane and carbon monoxide produced after the reaction is also doped with mixed vapor of some unreacted oxygen-containing chlorosilane and chlorosilane oligomers.

[0040] like Figure 1 As shown, the feed port of the cooling component 27 is connected to the discharge port of the chlorination furnace 10, which is used to cool the mixed gas of silicon tetrachloride, trichlorosilane and carbon monoxide passing through the cooling component 27, and discharge the carbon monoxide gas through the exhaust hole on the top of the cooling component 27.

[0041] For example, Figure 1 As shown, the cooling assembly 27 includes a primary silicon tetrachloride cooler 12 and a secondary silicon tetrachloride cooler 13 which are interconnected.

[0042] Exemplarily, both the silicon tetrachloride primary cooler 12 and the silicon tetrachloride secondary cooler 13 are provided with exhaust holes for exhausting carbon monoxide gas.

[0043] Exemplarily, the silicon tetrachloride primary cooler 12 and the silicon tetrachloride secondary cooler 13 are both circulating water coolers, and the temperature of the circulating water introduced is between 30°C and 40°C.

[0044] The mixed gas of silicon tetrachloride and trichlorosilane produced by the reaction in the chlorination furnace 10 is cooled by the silicon tetrachloride primary cooler 12, and its temperature drops from 500°C-650°C to 200°C-450°C. After being cooled by the silicon tetrachloride secondary cooler 13, its temperature drops from 200°C-450°C to 30-50°C.

[0045] By providing the interconnected silicon tetrachloride primary cooler 12 and silicon tetrachloride secondary cooler 13, a better cooling effect can be achieved on the mixed gas of silicon tetrachloride, trichlorosilane and carbon monoxide, so as to condense the gaseous silicon tetrachloride and trichlorosilane into liquid phase and discharge the gaseous carbon monoxide.

[0046] It is understandable that the unreacted mixed vapor of oxygen-containing chlorosilane and chlorosilane oligomers will also be condensed into liquid oxygen-containing chlorosilane and chlorosilane oligomers by the cooling component 27 and finally transported to the separation component 28 .

[0047] like Figure 1 As shown, the feed port of the separation component 28 is connected to the discharge port of the cooling component 27 for separating silicon tetrachloride, and the discharge port thereof is connected to the silicon tetrachloride storage device B.

[0048] The silicon tetrachloride separated from the separation module 28 is stored in a silicon tetrachloride storage device B.

[0049] Thus, the oxygen-containing chlorosilane waste recycling device provided by the embodiment of the utility model can separate metal chlorides and solid particles from the oxygen-containing chlorosilane waste by setting a scraper evaporator 2, thereby preventing the above-mentioned metal chlorides and solid particles from clogging the pipelines and equipment in the subsequent process and causing damage. By setting a deweighting tower 3, silicon tetrachloride can be separated from the oxygen-containing chlorosilane waste, and the mixture of oxygen-containing chlorosilane and chlorosilane oligomers remaining in the oxygen-containing chlorosilane waste is transported to the vaporizer 9, and after evaporation in the vaporizer 9, it enters the chlorination furnace 10 to react with the carbon reducing agent and chlorine to generate silicon tetrachloride, trichlorosilane and carbon monoxide, and then the carbon monoxide is discharged in the cooling component 27. By setting a separation component 28, silicon tetrachloride can be separated, thereby realizing the conversion and recycling of chlorosilane oligomers and oxygen-containing chlorosilane in the oxygen-containing chlorosilane waste, reducing the loss of valuable elements such as silicon and chlorine and the waste water and waste solids generated thereby, which is conducive to reducing the operating cost of the polysilicon production process.

[0050] In some embodiments, a filter 11 is further provided between the gas phase outlet of the chlorination furnace 10 and the feed inlet of the cooling assembly 27 for filtering the carbon reducing agent.

[0051] Exemplarily, the pore size of the filter 11 ranges from 40 mesh to 500 mesh.

[0052] By providing the filter 11, unreacted carbon reducing agent in the gas output from the gas phase outlet of the chlorination furnace 10 can be filtered out to prevent the carbon reducing agent from clogging pipelines and equipment in subsequent processes.

[0053] In some embodiments, Figure 1 As shown, a silicon tetrachloride buffer tank 14 is provided between the discharge port of the cooling component 27 and the feed port of the separation component 28. The silicon tetrachloride buffer tank 14 is used to temporarily store the materials entering the inside thereof. An exhaust hole is provided at the top of the silicon tetrachloride buffer tank 14 for further exhausting carbon monoxide.

[0054] By providing the silicon tetrachloride buffer tank 14 , the liquid silicon tetrachloride and trichlorosilane output from the discharge port of the cooling component 27 can be temporarily stored, thereby maintaining the stability of the amount of silicon tetrachloride and trichlorosilane delivered to the separation component 28 .

[0055] In some embodiments, Figure 1 As shown, a silicon tetrachloride delivery pump 15 is also provided between the silicon tetrachloride buffer tank 14 and the separation assembly 28 .

[0056] Through the above arrangement, the delivery capacity of liquid silicon tetrachloride and trichlorosilane from the silicon tetrachloride buffer tank 14 to the separation component 28 can be increased, and the delivery speed of the material to the separation component 28 can be controlled by controlling the working state of the silicon tetrachloride delivery pump 15 (such as the speed).

[0057] In some embodiments, Figure 1 As shown, the separation component 28 includes a chlorination deweighting tower 16 and a product tower 21. The feed port of the chlorination deweighting tower 16 is connected to the discharge port of the cooling component 27, and is used to separate unreacted oxygen-containing chlorosilane and chlorosilane oligomers. The bottom of the tower kettle is connected to the feed port of the vaporizer 9 to transport the unreacted oxygen-containing chlorosilane and chlorosilane oligomers to the vaporizer 9 for re-vaporization, and the gas phase outlet is used to output a mixed gas of silicon tetrachloride and trichlorosilane.

[0058] It can be understood that the unreacted gaseous oxygen-containing chlorosilane and chlorosilane oligomers in the chlorination furnace 10 are condensed into liquid phase by the cooling component 27 and then enter the chlorination deweighting tower 16 together with the liquid phase silicon tetrachloride and trichlorosilane.

[0059] Exemplarily, the feed inlet of the chlorination deweighting tower 16 is arranged at the middle and lower part of the chlorination deweighting tower 16. 4-10 sections of packing are arranged in the chlorination deweighting tower 16, the operating pressure is set between 100KPaG-250KPaG, the tower top operating temperature is set between 85°C-100°C, the tower top reflux ratio is set to 1-12, and the tower bottom operating temperature is set between 145°C-170°C.

[0060] After the chlorination deweighting tower 16 separates the materials inside, a mixed gas of silicon tetrachloride and trichlorosilane is separated from the top of the chlorination deweighting tower 16, and unreacted heavy components such as oxygen-containing chlorosilane and chlorosilane oligomers are separated from the bottom of the tower and returned to the vaporizer 9 for vaporization again, and then enter the chlorination furnace 10 again to continue the reaction.

[0061] like Figure 1 As shown, the feed port of the product tower 21 is connected to the gas phase outlet of the chlorination deweighting tower 16, which is used to separate silicon tetrachloride from the mixed gas of silicon tetrachloride and trichlorosilane. Its gas phase outlet is connected to the light component storage device C, which is used to store the gaseous trichlorosilane separated from the top of the tower in the light component storage device C through the gas phase outlet of the product tower 21. The bottom of the tower kettle is connected to the silicon tetrachloride storage device B, which is used to store the silicon tetrachloride separated from the tower kettle in the silicon tetrachloride storage device B.

[0062] Exemplarily, the feed inlet of the product tower 21 is arranged at the upper part of the product tower 21. The product tower 21 is provided with 4-10 sections of packing, the operating pressure is set between 80KPaG-120KPaG, the tower top operating temperature is set between 40-50°C, the tower top reflux ratio is 3-12, and the tower bottom operating temperature is set between 100°C-150°C.

[0063] After the product tower 21 separates the materials inside, gaseous trichlorosilane is separated from the top of the tower, and gaseous silicon tetrachloride is separated from the bottom of the tower. Thus, silicon tetrachloride and trichlorosilane are separated from the mixed gas of silicon tetrachloride and trichlorosilane, and valuable elements such as silicon and chlorine are recycled and utilized, thereby reducing the operating cost in the polysilicon production process.

[0064] In some embodiments, Figure 1 As shown, the separation assembly 28 also includes a chlorination de-weighting tower reboiler 20. The feed port of the chlorination de-weighting tower reboiler 20 is connected to the tower bottom of the chlorination de-weighting tower 16, and is used to heat up and vaporize the liquid silicon tetrachloride and liquid trichlorosilane in the tower bottom of the chlorination de-weighting tower 16 again. The discharge port of the chlorination de-weighting tower reboiler 20 is connected to the inside of the chlorination de-weighting tower 16, and is used to transport the heated and vaporized materials back to the inside of the chlorination de-weighting tower 16.

[0065] A reboiler is a special heat exchanger that can exchange heat and has a vaporization space.

[0066] The material level in the chlorination weight removal tower reboiler 20 is at the same height as the material level in the tower bottom of the chlorination weight removal tower 16. Liquid-phase material is provided from the tower bottom of the chlorination weight removal tower 16 to enter the chlorination weight removal tower reboiler 20, 25%-30% of the liquid-phase material is vaporized in the chlorination weight removal tower reboiler 20, and the vaporized two-phase material is sent back to the chlorination weight removal tower 16, and the gas-phase material in the chlorination weight removal tower 16 passes upward through the tower top, while the liquid-phase material falls back to the tower bottom.

[0067] The chlorination deweighting tower reboiler 20 is used together with the chlorination deweighting tower 16 to improve the separation effect and separation speed of the chlorination deweighting tower 16.

[0068] In some embodiments, the separation assembly 28 further includes a product tower reboiler 26. The feed port of the product tower reboiler 26 is connected to the bottom of the tower kettle of the product tower 21, and is used to heat up and vaporize the liquid phase trichlorosilane in the tower kettle of the product tower 21 again; the discharge port of the product tower reboiler 26 is connected to the interior of the product tower 21, and is used to transport the heated and vaporized material back to the interior of the product tower 21.

[0069] Similar to the above-mentioned chlorination deweighting tower reboiler 20 , the product tower reboiler 26 is used together with the product tower 21 to improve the separation effect and separation speed of the product tower 21 .

[0070] In some embodiments, Figure 1 As shown, the separation component 28 also includes a chlorination weight removal tower top condenser 17, a chlorination weight removal tower top reflux tank 18 and a chlorination weight removal tower top reflux pump 19.

[0071] The feed inlet of the chlorination de-weighting tower top condenser 17 is communicated with the gas phase outlet of the chlorination de-weighting tower 16, and is used to condense the mixed gas of silicon tetrachloride and trichlorosilane into a liquid phase mixture.

[0072] The feed inlet of the reflux tank 18 at the top of the chlorination weight removal tower is communicated with the discharge port of the condenser 17 at the top of the chlorination weight removal tower, and is used for temporarily storing the liquid phase mixture of silicon tetrachloride and trichlorosilane.

[0073] The feed port of the reflux pump 19 at the top of the chlorination weight-removing tower is connected to the discharge port of the reflux tank 18 at the top of the chlorination weight-removing tower, and its discharge port is respectively connected to the inside of the chlorination weight-removing tower 16 and the feed port of the product tower 21, so as to transport a part of the liquid mixture of silicon tetrachloride and trichlorosilane to the inside of the chlorination weight-removing tower 16, and transport another part of the liquid mixture of silicon tetrachloride and trichlorosilane to the product tower 21.

[0074] Through the above arrangement, the normal separation process of the materials in the chlorination deweighting tower 16 can be maintained, and the purity of silicon tetrachloride and trichlorosilane transported to the product tower 21 can be improved.

[0075] In some embodiments, the separation component 28 further includes a product tower top condenser 23 , a product tower top reflux drum 24 , and a product tower top reflux pump 25 .

[0076] The feed inlet of the product tower top condenser 23 is connected to the gas phase outlet of the product tower 21, and is used to condense gaseous trichlorosilane into liquid trichlorosilane. The feed inlet of the product tower top reflux tank 24 is connected to the discharge port of the product tower top condenser 23, and is used to temporarily store liquid trichlorosilane. The feed inlet of the product tower top reflux pump 25 is connected to the discharge port of the product tower top reflux tank 24, and its discharge port is respectively connected to the inside of the product tower 21 and the light component storage device C, and is used to transport a part of the liquid trichlorosilane to the inside of the product tower 21, and transport another part of the liquid trichlorosilane to the light component storage device C.

[0077] Through the above arrangement, the normal separation process of the materials inside the product tower 21 can be maintained, and the purity of the trichlorosilane transported to the light component storage device C can be improved.

[0078] In some embodiments, Figure 1 As shown, a de-weighting tower reboiler 8 is provided outside the de-weighting tower 3, and the feed port of the de-weighting tower reboiler 8 is connected to the tower kettle of the de-weighting tower 3, so as to heat up and vaporize the materials in the tower kettle of the de-weighting tower 3 again. The discharge port of the de-weighting tower reboiler 8 is connected to the inside of the de-weighting tower 3, so as to transport the heated and vaporized materials back to the inside of the de-weighting tower 3.

[0079] Similar to the above-mentioned chlorination deweighting tower reboiler 20 and product tower reboiler 26, the deweighting tower reboiler 8 is used together with the deweighting tower 3 to improve the separation effect and separation speed of the deweighting tower 3.

[0080] In some embodiments, Figure 1 As shown, a weight removal tower top condenser 5, a weight removal tower top reflux tank 6 and a weight removal tower top reflux pump 7 are also provided between the gas phase outlet of the weight removal tower 3 and the silicon tetrachloride storage device.

[0081] The feed inlet of the top condenser 5 of the de-weighting tower is connected to the gas phase outlet of the de-weighting tower 3, and is used to condense the gas phase silicon tetrachloride into liquid phase silicon tetrachloride. The feed inlet of the top reflux tank 6 of the de-weighting tower is connected to the discharge port of the top condenser 5 of the de-weighting tower, and is used to temporarily store the liquid phase silicon tetrachloride. The feed inlet of the top reflux pump 7 of the de-weighting tower is connected to the discharge port of the top reflux tank 6 of the de-weighting tower, and the discharge port of the top reflux pump 7 of the de-weighting tower is connected to the inside of the de-weighting tower 3 and the silicon tetrachloride storage device, respectively, for transporting a part of the liquid phase silicon tetrachloride to the inside of the de-weighting tower 3, and transporting another part of the liquid phase silicon tetrachloride to the silicon tetrachloride storage device B.

[0082] Through the above arrangement, the normal separation process of the materials inside the deweighting tower 3 can be maintained, and the purity of the silicon tetrachloride transported to the silicon tetrachloride storage device B can be improved.

[0083] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A device for recycling waste oxygen-containing chlorosilane, characterized in that: include: A scraper evaporator (2), the feed port of which is used to receive the oxychlorosilane waste liquid and to evaporate and separate the oxychlorosilane waste liquid, and the bottom of the tower kettle of the scraper evaporator (2) is connected to the hydrolysis device; A deweighting tower (3), whose feed port is communicated with the gas phase outlet of the scraper evaporator (2), and is used for deweighting and rectifying the evaporated mixed vapor of oxygen-containing chlorosilane, chlorosilane oligomers and silicon tetrachloride, and whose gas phase outlet is communicated with a silicon tetrachloride storage device, and the gaseous silicon tetrachloride separated from the tower top enters the silicon tetrachloride storage device through the gas phase outlet of the deweighting tower (3) for storage; A vaporizer (9), the feed port of which is connected to the bottom of the kettle of the deweighting tower (3), and is used to heat and vaporize the mixture of oxygen-containing chlorosilane and chlorosilane oligomer separated from the kettle of the deweighting tower (3); a chlorination furnace (10), the feed port of which is in communication with the discharge port of the vaporizer (9); the chlorination furnace (10) is also in communication with a carbon reducing agent feed pipe and a chlorine gas feed pipe respectively, and is used to react various materials entering the chlorination furnace to generate silicon tetrachloride, trichlorosilane and carbon monoxide; a cooling assembly (27), whose feed port is communicated with the discharge port of the chlorination furnace (10), for cooling the mixed gas of silicon tetrachloride, trichlorosilane and carbon monoxide passing through the cooling assembly (27), and discharging the carbon monoxide gas through the exhaust hole at the top of the cooling assembly (27); and, A separation component (28) has a feed port connected to the discharge port of the cooling component (27) and is used to separate silicon tetrachloride, and a discharge port connected to the silicon tetrachloride storage device.

2. The device according to claim 1, characterized in that The separation assembly (28) comprises: a chlorination deweighting tower (16), whose feed port is connected to the discharge port of the cooling assembly (27) and is used to separate unreacted oxygen-containing chlorosilane and chlorosilane oligomers, whose bottom is connected to the feed port of the vaporizer (9) to transport the unreacted oxygen-containing chlorosilane and chlorosilane oligomers to the vaporizer (9) for re-vaporization, and whose gas phase outlet is used to output a mixed gas of silicon tetrachloride and trichlorosilane; and, The product tower (21) has a feed inlet connected to the gas phase outlet of the chlorination deweighting tower (16) and is used to separate silicon tetrachloride from the mixed gas of silicon tetrachloride and trichlorosilane. The gas phase outlet is connected to a light component storage device and is used to store the gaseous trichlorosilane separated from the tower top in the light component storage device through the gas phase outlet of the product tower (21). The bottom of the tower kettle is connected to the silicon tetrachloride storage device and is used to store the silicon tetrachloride separated from the tower kettle in the silicon tetrachloride storage device.

3. The device according to claim 2, characterized in that The separation assembly (28) further comprises a chlorination deweighting tower reboiler (20); The feed port of the chlorination de-weighting tower reboiler (20) is communicated with the bottom of the chlorination de-weighting tower (16), so as to heat up and vaporize the liquid silicon tetrachloride and liquid trichlorosilane in the bottom of the chlorination de-weighting tower (16) again; the discharge port of the chlorination de-weighting tower reboiler (20) is communicated with the interior of the chlorination de-weighting tower (16), so as to transport the heated and vaporized materials back to the interior of the chlorination de-weighting tower (16).

4. The device according to claim 2, characterized in that The separation assembly (28) also includes a product column reboiler (26); The feed port of the product tower reboiler (26) is communicated with the bottom of the kettle of the product tower (21) so as to heat up and vaporize the liquid trichlorosilane in the kettle of the product tower (21) again; the discharge port of the product tower reboiler (26) is communicated with the interior of the product tower (21) so as to transport the heated and vaporized material back to the interior of the product tower (21).

5. The device according to claim 2, characterized in that The separation assembly (28) further comprises: a chlorination deweighting tower top condenser (17), the feed port of which is connected to the gas phase outlet of the chlorination deweighting tower (16), and is used to condense the mixed gas of silicon tetrachloride and trichlorosilane into a liquid phase mixture; A reflux tank (18) at the top of the chlorination weight removal tower, the feed port of which is connected to the discharge port of the condenser (17) at the top of the chlorination weight removal tower, for temporarily storing a liquid mixture of silicon tetrachloride and trichlorosilane; and, A chlorination weight removal tower top reflux pump (19), whose feed port is connected to the discharge port of the chlorination weight removal tower top reflux tank (18), and whose discharge port is respectively connected to the inside of the chlorination weight removal tower (16) and the feed port of the product tower (21), is used to transport a part of the liquid phase mixture of silicon tetrachloride and trichlorosilane to the inside of the chlorination weight removal tower (16), and to transport another part of the liquid phase mixture of silicon tetrachloride and trichlorosilane to the product tower (21).

6. The device according to claim 2, characterized in that The separation assembly (28) further comprises: A product tower top condenser (23), whose feed port is connected to the gas phase outlet of the product tower (21), and is used to condense gaseous trichlorosilane into liquid trichlorosilane; A product tower top reflux tank (24), whose feed port is connected to the discharge port of the product tower top condenser (23), is used for temporarily storing liquid trichlorosilane; and, A product tower top reflux pump (25) has a feed port connected to a discharge port of the product tower top reflux tank (24), and a discharge port connected to the interior of the product tower (21) and the light component storage device, respectively, for conveying a portion of liquid trichlorosilane to the interior of the product tower (21) and conveying another portion of liquid trichlorosilane to the light component storage device.

7. The device according to claim 1, characterized in that A filter (11) is also provided between the gas phase outlet of the chlorination furnace (10) and the feed inlet of the cooling component (27) for filtering the carbon reducing agent.

8. The device according to claim 1, characterized in that A silicon tetrachloride buffer tank (14) is also provided between the discharge port of the cooling component (27) and the feed port of the separation component (28) for temporarily storing the material entering the silicon tetrachloride buffer tank (14); and an exhaust hole is provided at the top of the silicon tetrachloride buffer tank (14) for further exhausting carbon monoxide.

9. The device according to claim 1, characterized in that A deweighting tower reboiler (8) is arranged outside the deweighting tower (3), and a feed port of the deweighting tower reboiler (8) is connected to the bottom of the deweighting tower (3) for heating and vaporizing the material in the bottom of the deweighting tower (3) again; a discharge port of the deweighting tower reboiler (8) is connected to the inside of the deweighting tower (3) for transporting the heated and vaporized material back to the inside of the deweighting tower (3).

10. The device according to claim 1, characterized in that A de-weighting tower top condenser (5), a de-weighting tower top reflux tank (6) and a de-weighting tower top reflux pump (7) are also provided between the gas phase outlet of the de-weighting tower (3) and the silicon tetrachloride storage device; The feed inlet of the de-weighting tower top condenser (5) is connected to the gas phase outlet of the de-weighting tower (3) and is used to condense gaseous silicon tetrachloride into liquid silicon tetrachloride; The feed inlet of the reflux tank (6) at the top of the weight removal tower is connected to the discharge outlet of the condenser (5) at the top of the weight removal tower, and is used for temporarily storing liquid silicon tetrachloride; The feed inlet of the weight-removing tower top reflux pump (7) is connected to the discharge port of the weight-removing tower top reflux tank (6), and the discharge port of the weight-removing tower top reflux pump (7) is respectively connected to the inside of the weight-removing tower (3) and the silicon tetrachloride storage device, so as to transport a part of the liquid silicon tetrachloride to the inside of the weight-removing tower (3), and transport another part of the liquid silicon tetrachloride to the silicon tetrachloride storage device.

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