Sealing and pressurizing system for polysilicon production and method thereof

Abstract

The embodiment of the present application provides a sealing and pressurizing system for polycrystalline silicon production and a method thereof, and relates to the technical field of polycrystalline silicon production. The sealing and pressurizing system for polycrystalline silicon production comprises a storage tank, a separation device, a balance main pipe and a balance branch pipe. The storage tank and the balance branch pipe are respectively provided with multiple. The multiple storage tanks are used for storing storage medium with a first air pressure, the separation device is used for outputting sealing and pressurizing gas with a second air pressure, the first air pressure is equal to the second air pressure, a first air inlet end of the balance main pipe is selectively communicated with an output end of the separation device, and the multiple storage tanks are selectively communicated with a first air outlet end of the balance main pipe through the balance branch pipe. Through the above setting, the sealing and pressurizing system for polycrystalline silicon production and the method thereof can reduce resource consumption in the sealing and pressurizing process on the basis of guaranteeing sealing and pressurizing safety and pressure stability of the storage tank.

Description

Technical Field

[0001] This application relates to the field of polysilicon production technology, and in particular to a sealing system and method for polysilicon production. Background Technology

[0002] In polysilicon production, low-pressure chlorosilane storage tanks typically use inert gas sealing to maintain a slight positive pressure inside the tank, preventing air from entering and ensuring storage safety.

[0003] However, existing pressure sealing solutions mostly rely on continuous pressurization with high-purity hydrogen and adjusting the tank pressure through continuous venting. This not only results in high energy consumption in hydrogen preparation, purification, and transportation, but also in significant consumption of pressure sealing resources. Furthermore, the chlorosilane gas phase volatilized within the storage tank enters the subsequent processing system along with the vented gas, causing gaseous material loss. In addition, conventional gas supply networks experience pressure fluctuations, which can lead to insufficient tank pressure stability, frequent valve adjustments, and poor overall operational stability.

[0004] Therefore, how to reduce resource consumption and gaseous material loss during the sealing process while ensuring the safety and stability of the low-pressure chlorosilane storage tank has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a sealing system and method for polysilicon production, which can reduce resource consumption during the sealing process while ensuring the safety and pressure stability of the storage tank sealing.

[0006] In a first aspect, embodiments of this application provide a sealing system for polysilicon production, comprising:

[0007] Multiple storage tanks are used to store storage media with a pressure value of the first atmosphere;

[0008] A separation device is used to output a sealing gas with a pressure value of a second pressure, wherein the first pressure and the second pressure are equal;

[0009] A balance main pipe, wherein the first air inlet of the balance main pipe may be selectively connected to the output of the separation device;

[0010] Multiple balancing branch pipes, and multiple storage tanks are selectively connected to the first gas outlet of the main balancing pipe through the balancing branch pipes.

[0011] In one possible implementation, the separation device includes a separation mechanism, a first condensation mechanism, and a reflux mechanism. The separation mechanism is used to output a gaseous medium to the first condensation mechanism, and the output end of the first condensation mechanism is connected to the reflux mechanism.

[0012] In one possible implementation, the output end of the first condensation mechanism includes a first liquid outlet pipe and a first gas outlet pipe. The first liquid outlet pipe is connected to the separation mechanism through the reflux mechanism, and the first gas outlet pipe is connected to the reflux mechanism.

[0013] In one possible implementation, the separation device further includes a heat exchange mechanism and a second condensation mechanism. The input end of the heat exchange mechanism is selectively connected to the second outlet end of the reflux mechanism, and the output end of the heat exchange mechanism is connected to the second condensation mechanism. The third outlet end of the second condensation mechanism is connected to the first inlet end of the balance pipe for outputting the sealing gas.

[0014] In one possible implementation, the system further includes an exhaust gas treatment mechanism, wherein the third outlet of the second condensation mechanism can be selectively connected to the second inlet of the exhaust gas treatment mechanism via the heat exchange mechanism.

[0015] In one possible implementation, at least one regulating valve is further included, which is disposed between the reflux mechanism and the heat exchange mechanism for regulating the gas pressure of the gaseous medium within the separation mechanism;

[0016] And / or, the regulating valve is disposed between the heat exchange mechanism and the waste gas treatment mechanism, for regulating the pressure of the sealing gas in the second condensation mechanism.

[0017] In one possible implementation, the output end of the heat exchange mechanism includes a second liquid outlet pipe and a second gas outlet pipe, the second liquid outlet pipe being connected to the second condensation mechanism, and the separation device further includes a third condensation mechanism, the second gas outlet pipe being connected to the second condensation mechanism through the third condensation mechanism.

[0018] In one possible implementation, the separation device further includes an outlet pump and a receiving tank, the input end of the outlet pump being connected to the second condensation mechanism, and the output end of the outlet pump being connected to the receiving tank.

[0019] In one possible implementation, an emergency response mechanism is also included, the output of which may be selectively connected to the balance branch pipe for introducing emergency gas into the storage tank through the balance branch pipe.

[0020] Secondly, embodiments of this application provide a sealing method for polysilicon production, using the sealing system for polysilicon production as described above, including:

[0021] Sealing gas is prepared using a separation device;

[0022] Pressurized gas is introduced into the storage tank through the main and branch pipes to make the second pressure of the pressurized gas equal to the first pressure of the storage medium in the storage tank.

[0023] The volatile medium stored in the storage tank can be returned to the separation unit through the balance branch pipe and the balance main pipe.

[0024] The sealing system and method for polysilicon production provided in this application embodiment utilizes a separation device and multiple storage tanks. The storage medium within the tanks maintains a first pressure, while the sealing gas output from the separation device maintains a second pressure, and both pressures remain equal. The sealing gas, regulated by the separation device, is uniformly supplied to each storage tank, ensuring stable gas source pressure. This mitigates the impact of pipeline fluctuations on tank pressure, reduces frequent pressure regulation operations, stabilizes the sealing state of the tanks, and enhances equipment operational safety.

[0025] Furthermore, by setting up a main balancing pipe and branch balancing pipes, the separation unit can selectively connect to each storage tank. The pressure of the sealing gas remains consistent with the internal pressure of the storage tank, eliminating the need for continuous pressurization and frequent venting for pressure stabilization. This reduces energy and resource consumption associated with continuous gas supply and venting. The volatile media stored in the tanks can be returned to the separation unit for further separation and recovery, preventing loss of volatile media with the venting exhaust gas and minimizing resource waste.

[0026] With the above-mentioned configuration, the sealing system and method for polysilicon production of this application reduces resource consumption during the sealing process while ensuring the safety and pressure stability of the storage tank sealing. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0028] Figure 1 This is a schematic diagram of a sealing system for polysilicon production provided in an embodiment of this application;

[0029] Figure 2 A flowchart of a sealing method for polysilicon production provided in an embodiment of this application.

[0030] Figure label:

[0031] 10. Control mechanism; 20. First pressure sensor; 30. Second pressure sensor;

[0032] 100. Storage tank; 200. Separation device; 210. Separation mechanism; 220. First condensation mechanism; 221. First liquid outlet pipe; 222. First gas outlet pipe; 230. Reflux mechanism; 231. Second gas outlet; 240. Heat exchange mechanism; 241. Second liquid outlet pipe; 242. Second gas outlet pipe; 250. Second condensation mechanism; 251. Third gas outlet; 260. Third condensation mechanism; 300. Main balance pipe; 310. First gas inlet; 320. First gas outlet; 400. Balance branch pipe; 500. Waste gas treatment mechanism; 510. Second gas inlet; 600. Regulating valve; 700. Liquid discharge pump; 800. Collection tank; 900. Emergency mechanism.

[0033] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Polysilicon production involves multiple stages, including cold hydrogenation, distillation, and material storage and transportation. Low-pressure chlorosilane media such as trichlorosilane, silicon tetrachloride, and dichlorosilane typically need to be stored in tanks under a slightly positive pressure to prevent hydrolysis, corrosion, and safety risks caused by air ingress. Around these storage tanks, a pressure-sealing gas source, gas connection pipelines, and pressure regulating units are usually configured on-site to form a pressure-sealing system for maintaining pressure balance within the tank.

[0036] In existing low-pressure chlorosilane storage tank sealing schemes, high-purity hydrogen is typically used as the inert sealing medium, and gas is continuously supplied to each storage tank through an external gas supply network. When the pressure inside the storage tank drops, the sealing gas enters the compensation gas phase space inside the tank; when the pressure rises, a portion of the mixed gas is released through venting to maintain the storage tank within the set pressure range. Although this method can achieve basic sealing functionality, the system operation relies on continuous gas supply and repeated venting, resulting in high overall energy consumption.

[0037] Meanwhile, the chlorosilane gas volatilized from the storage tank will enter subsequent processing stages along with the vented gas, resulting in the loss of usable materials and increasing the load on the exhaust gas treatment. Because the sealing process is affected by external gas supply pressure, fluctuations in gas consumption in each tank, and the condition of the pipeline network, the storage tank pressure is also prone to fluctuations, leading to frequent adjustments and insufficient operational stability. Under conditions of large-scale continuous production, these problems will be further amplified, not only increasing production costs but also jeopardizing the safety of the storage tank sealing and the long-term stable operation of the system.

[0038] In view of this, how to reduce resource consumption and gaseous material loss during the sealing process while ensuring the safety and stability of the low-pressure chlorosilane storage tanks has become an urgent technical problem to be solved. To solve the above technical problem, this application provides a sealing system for polysilicon production. By setting up multiple storage tanks, a separation device for outputting sealing gas, and a balancing main pipe and multiple balancing branch pipes connected to the multiple storage tanks, the system matches the sealing gas pressure with the storage medium pressure, achieving gas phase balance between the multiple storage tanks and the sealing gas source. This provides a technical basis for reducing sealing consumption and improving system stability.

[0039] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0040] See Figure 1 and Figure 2 This application provides a sealing system for polysilicon production, including a storage tank 100, a separation device 200, a main balancing pipe 300, and a branch balancing pipe 400. Multiple storage tanks 100 and branch balancing pipes 400 are provided. The multiple storage tanks 100 are used to store a storage medium with a first gas pressure. The separation device 200 is used to output sealing gas with a second gas pressure, where the first and second gas pressures are equal. The first inlet 310 of the main balancing pipe 300 is selectively connected to the output end of the separation device 200. The multiple storage tanks 100 are selectively connected to the first outlet 320 of the main balancing pipe 300 via the branch balancing pipes 400.

[0041] In this embodiment, the sealing system and method for polysilicon production provided in this application includes a separation device 200 and multiple storage tanks 100. The storage medium in the storage tanks 100 maintains a first pressure, and the sealing gas output from the separation device 200 maintains a second pressure, with both pressures remaining equal. The sealing gas, regulated by the separation device 200, supplies gas to each storage tank 100 uniformly. This stable gas source pressure mitigates the impact of pipeline fluctuations on the pressure of the storage tanks 100, reduces frequent pressure regulation operations, stabilizes the sealing state of the storage tanks 100, and improves equipment operational safety.

[0042] Furthermore, by setting up a balancing main pipe 300 and balancing branch pipes 400, the separation device 200 can selectively connect to each storage tank 100. The pressure of the sealing gas is consistent with the internal pressure of the storage tank 100, eliminating the need for continuous gas supply and pressure replenishment, as well as frequent venting and pressure stabilization. This reduces the energy and resource consumption caused by continuous gas supply and venting. The volatile medium stored in the storage tank 100 can be returned to the separation device 200 and re-participated in the separation and recovery process, preventing the volatile medium from being lost with the venting exhaust gas and reducing resource consumption.

[0043] With the above-mentioned setup, the sealing system and method for polysilicon production of this application reduces resource consumption during the sealing process while ensuring the sealing safety and pressure stability of the storage tank 100.

[0044] Specifically, in this embodiment, the storage tank 100 is a pressure tank and / or emergency tank for containing chlorosilane media. Multiple storage tanks 100 can respectively store volatile media such as trichlorosilane, silicon tetrachloride, and dichlorosilane, stably maintain a slightly positive pressure storage environment inside the tank, avoid the intrusion of external air causing media hydrolysis and equipment corrosion, and at the same time provide a sealed containment space for the volatilization of the media inside the tank and the gas phase balance reflux.

[0045] In other embodiments, the storage tank 100 may be a vertical pressure tank, a horizontal pressure tank, or a corrosion-resistant pressure vessel with an insulation jacket. Such storage tank 100 can be adapted to different tank area layout spaces and media storage conditions, and can also achieve the functions of closed storage and gas phase pressure stabilization of chlorosilane media. No further limitations are made here.

[0046] In one possible embodiment, the main balance pipe 300 serves as the main delivery pipeline, which can collect the sealing gas output from the separation device 200 and then distribute it to each storage tank 100 through multiple independent balance branch pipes 400. Each balance branch pipe 400 corresponds independently to one storage tank 100, so that the on / off state of a single balance branch pipe 400 can be controlled individually, thereby realizing independent on / off control between a single storage tank 100 and the sealing gas.

[0047] It should be noted that the storage medium stored inside storage tank 100 includes at least one or more of trichlorosilane, silicon tetrachloride, and dichlorosilane. These media are easily hydrolyzed, flammable, and explosive chlorosilane materials, requiring the maintenance of a slight positive pressure inside storage tank 100 to prevent outside air from entering. The sealing gas output from separation device 200 is selected from a hydrogen-containing mixed gas byproduct of the polycrystalline silicon process. This gas can be directly used as the sealing medium, eliminating the need for an additional high-purity hydrogen source.

[0048] In other embodiments, the separation device 200 can be a membrane separation device, an adsorption separation device, or a pressure stabilizing device with a matching pressure regulating component; the balance main pipe 300 and the balance branch pipe 400 can be made of stainless steel pipe or fluoropolymer-lined anti-corrosion pipe. As long as the separation device 200 can output a stable second pressure sealing gas, and the balance main pipe 300 and the balance branch pipe 400 can form a connecting pipeline allowing bidirectional gas phase flow, thus realizing gas phase exchange between the storage tank 100 and the separation device 200, this application does not impose excessive limitations on the above components.

[0049] In one possible embodiment, the first gas pressure corresponding to the storage medium inside the storage tank 100 ranges from 1.0 barG to 1.9 barG, and the second gas pressure of the sealing gas output by the separation device 200 is consistent with the first gas pressure. Here, barG is a gauge pressure unit, using the local ambient atmospheric pressure as the zero point, and characterizing pressures exceeding atmospheric pressure.

[0050] When the initial pressure is 1.0 barG, it is suitable for low-load production conditions of the equipment. The lower system pressure can reduce the pressure load on pipelines and tanks, and reduce the potential risk of gaseous media leakage.

[0051] When the initial pressure is 1.4 barG, it is suitable for continuous operation under medium load conditions, taking into account both pipeline transport capacity and equipment pressure requirements, and is compatible with most normal operating ranges.

[0052] When the first pressure is 1.9 barG, it is suitable for the stable production conditions of the equipment at full load. The higher internal pressure can effectively resist external wind pressure fluctuations and prevent air backflow. At the same time, it matches the stable gas supply pressure of the separation device 200 to ensure smooth operation of the gas phase closed-loop circulation.

[0053] In one possible embodiment, the separation device 200 includes a separation mechanism 210, a first condensation mechanism 220 and a reflux mechanism 230. The separation mechanism 210 is used to output a gaseous medium to the first condensation mechanism 220, and the output end of the first condensation mechanism 220 is connected to the reflux mechanism 230.

[0054] Among them, the separation unit 210, as the front-end gas phase coarse separation unit, can continuously discharge high-temperature gas phase medium. The components of the gas phase medium include hydrogen, gaseous trichlorosilane, gaseous silicon tetrachloride, gaseous dichlorosilane, and hydrogen chloride.

[0055] The first condensation unit 220 is located downstream of the separation unit 210 and can receive the high-temperature gaseous medium output from the separation unit 210. The first condensation unit 220 can cool the gaseous medium. During the heat exchange and cooling process, some of the condensable chlorosilane components such as trichlorosilane, silicon tetrachloride, and dichlorosilane in the gaseous medium will liquefy and precipitate to form liquid chlorosilanes, so as to achieve effective recovery of the chlorosilane components.

[0056] The portion of the gaseous medium that has not condensed after heat exchange, along with the liquid chlorosilane obtained from condensation, is fed into the reflux mechanism 230. The reflux mechanism 230 can receive the gas-liquid two-phase medium output from the first condensation mechanism 220, thereby temporarily storing and buffering the liquid chlorosilane, and guiding the uncondensed gaseous medium to subsequent equipment, so as to maintain the overall pressure and flow rate of the separation device 200.

[0057] More specifically, in this embodiment, the separation mechanism 210 adopts a distillation column, which can achieve fine separation of the components of chlorosilane and ensure the stability of the gas phase composition at the top of the column. In other embodiments, the separation mechanism 210 can also be a coarse separation column, which has lower energy consumption and is suitable for preliminary purification of the gas phase. As long as the separation mechanism 210 can complete the preliminary purification and transportation of the gas phase medium, this application does not impose too many limitations on the specific structure of the separation mechanism 210.

[0058] In one possible embodiment, the first condensing mechanism 220 adopts a shell-and-tube condenser, which is circulated with cooling water as the cooling medium. The continuous heat exchange loop is formed by the upper and lower water of the circulating cooling water, thereby cooling the high-temperature gaseous medium and ensuring stable operation of the condensing condition.

[0059] In other embodiments, the first condensing mechanism 220 can be a plate condenser, which has high heat exchange efficiency, small footprint, and can quickly reduce the temperature of the gaseous medium; or, the first condensing mechanism 220 can be a coil condenser, which has simple structure, excellent sealing performance, and is easy to adapt to corrosive chlorosilane media conditions. As long as the first condensing mechanism 220 can achieve cooling and condensation of the gaseous medium, this application does not limit the equipment model or structural form of the first condensing mechanism 220.

[0060] In one possible embodiment, the reflux mechanism 230 may include a reflux tank and a matching conveying pipeline. The matching conveying pipeline may be equipped with a check valve and a throttle valve. The check valve enables unidirectional flow of the medium and prevents backflow of the medium, while the throttle valve can be used to regulate the flow rate of the medium and stabilize the pressure.

[0061] In other possible embodiments, the reflux mechanism 230 may include a level control valve assembly to automatically regulate the discharge rate of liquid chlorosilane via a level signal, thereby facilitating the maintenance of a stable liquid level within the tank. As long as the reflux mechanism 230 can receive and buffer the gas-liquid two-phase medium, this application does not impose excessive limitations on the specific structural form of the reflux mechanism 230.

[0062] It should be noted that, since the separation mechanism 210, the first condensation mechanism 220 and the reflux mechanism 230 are in long-term contact with corrosive media containing hydrogen chloride and chlorosilanes, the materials of the above components can be stainless steel, carbon steel with an anti-corrosion lining, Hastelloy or fluoroplastic composite materials to meet the requirements of resistance to chlorosilane and hydrogen chloride corrosion.

[0063] In one possible embodiment, the output end of the first condensation mechanism 220 includes a first liquid outlet pipe 221 and a first gas outlet pipe 222. The first liquid outlet pipe 221 can be connected to the separation mechanism 210 through the reflux mechanism 230, and the first gas outlet pipe 222 is connected to the reflux mechanism 230.

[0064] The liquid chlorosilane transported via the first liquid outlet pipe 221 can be returned to the separation mechanism 210 for further separation and purification, realizing the recycling of liquid phase materials; while the uncondensed gaseous medium transported via the first gas outlet pipe 222 can be sent to the reflux mechanism 230 for subsequent transport. Through the gas-liquid separation transport method, liquid phase reflux and gas phase transport can be completed separately.

[0065] Specifically, in this embodiment, the first liquid outlet pipe 221 and the first gas outlet pipe 222 can be connected to the first condensation mechanism 220 by welding, which has good sealing performance and can be adapted to the sealing requirements of chlorosilane media; in other embodiments, the first liquid outlet pipe 221 and the first gas outlet pipe 222 can also be connected by flanges or sealing joints, which makes disassembly and maintenance convenient.

[0066] As long as the first liquid outlet pipe 221 and the first gas outlet pipe 222 can be stably connected to the first condensing mechanism 220 and the medium can be transported, this application does not impose too many restrictions on the specific connection form between the above-mentioned pipes and the first condensing mechanism 220.

[0067] It should be noted that the first liquid outlet pipe 221 and the first gas outlet pipe 222 are in long-term contact with the corrosive medium of chlorosilane. The pipe material can be 304 stainless steel, 316L stainless steel or carbon steel lined with PTFE, as long as it meets the requirements for long-term corrosion resistance.

[0068] In one possible embodiment, the separation device 200 further includes a heat exchange mechanism 240 and a second condensation mechanism 250. The input end of the heat exchange mechanism 240 is optionally connected to the second outlet end 231 of the reflux mechanism 230, and the output end of the heat exchange mechanism 240 is connected to the second condensation mechanism 250. The third outlet end 251 of the second condensation mechanism 250 is connected to the first inlet end 310 of the balance main pipe 300 for outputting sealing gas.

[0069] The uncondensed gaseous medium delivered through the second outlet 231 of the reflux mechanism 230 can be passed into the heat exchange mechanism 240 to complete heat exchange and cooling, causing the condensable chlorosilane components entrained in the gaseous medium to liquefy and precipitate. The cooled medium can then enter the second condensation mechanism 250 to complete gas-liquid separation, removing liquid droplets from the medium. After heat exchange and deep condensation separation, the medium can be sent to the balance main pipe 300 through the third outlet 251 for use as a sealing gas, effectively reducing the liquid entrainment in the sealing gas and improving its purity.

[0070] Specifically, in this embodiment, the heat exchange mechanism 240 adopts a shell-and-tube heat exchanger, which has stable heat exchange and is suitable for continuous cooling of process gas medium. In other embodiments, the heat exchange mechanism 240 may also adopt a plate heat exchanger or a finned cooling coil to adapt to different site layouts and heat exchange load requirements.

[0071] It should be understood that as long as the heat exchange mechanism 240 can exchange heat and cool the medium delivered by the return mechanism 230, this application does not impose too many restrictions on the specific type of the heat exchange mechanism 240.

[0072] Specifically, in this embodiment, the second condensation mechanism 250 adopts a deep condensate tank for exhaust gas, achieving efficient gas-liquid separation through gravity settling. This design is simple in structure and stable in operation. Furthermore, a gas-to-liquid connection is formed between the deep condensate tank and the storage tank 100 via the main balance pipe 300 and the branch balance pipe 400, eliminating the need for intermediate equipment such as buffer tanks or reflux tanks. This allows for gas-to-liquid communication between the deep condensate tank and each storage tank 100, achieving gas-phase medium pressure balance and medium circulation. In other embodiments, the second condensation mechanism 250 may also employ a cyclone separator or a demisting separation unit to further enhance the removal of fine mist droplets.

[0073] It should be understood that as long as the second condensing mechanism 250 can complete the gas-liquid separation of the cooled mixed medium and output the sealing gas, this application does not impose too many restrictions on the specific structural form of the second condensing mechanism 250.

[0074] It should be noted that the heat exchange mechanism 240 and the second condensation mechanism 250 are in long-term contact with corrosive gaseous media containing hydrogen, chlorosilane vapor, and hydrogen chloride. The shell, heat exchange components and connecting pipes of the above mechanisms can be made of corrosion-resistant materials such as stainless steel, carbon steel with anti-corrosion lining, and Hastelloy, which can meet the requirements for long-term anti-corrosion operation.

[0075] In one possible embodiment, the sealing system for polysilicon production further includes an exhaust gas treatment mechanism 500, wherein the third exhaust end 251 of the second condensation mechanism 250 can be selectively connected to the second intake end 510 of the exhaust gas treatment mechanism 500 via a heat exchange mechanism 240.

[0076] The third air outlet 251 of the second condensing mechanism 250 can be selectively connected to the second air inlet 510 of the exhaust gas treatment mechanism 500 through the heat exchange mechanism 240. That is, the above passage serves as an overpressure safety relief pipeline, which can achieve selective switching of operating conditions.

[0077] Under normal operating conditions, all gaseous media processed by the second condensation mechanism 250 are transported to the balance main pipe 300 to act as a sealing gas to seal the storage tank 100. When the system experiences an abnormal overpressure condition, the hydrogen-containing non-condensable gas output by the second condensation mechanism 250 can be introduced into the waste gas treatment mechanism 500 for harmless treatment via the heat exchange mechanism 240. The above settings can prioritize the normal sealing operation of the system and provide a safe pressure relief channel for the system under overpressure conditions, thereby improving the operational safety of the system.

[0078] Specifically, in this embodiment, the waste gas treatment unit 500 can be a scrubbing tower, which can wash and purify the residual chlorosilane and hydrogen chloride components in the hydrogen-containing non-condensable gas; in other embodiments, the waste gas treatment unit 500 can also be an adsorption tower, a low-temperature condensation recovery device or a combustion treatment unit, to adapt to different tail gas treatment process requirements.

[0079] It should be understood that as long as the exhaust gas treatment device 500 can complete the harmless treatment of the depressurized exhaust gas, this application does not impose too many restrictions on the type of equipment of the exhaust gas treatment device 500.

[0080] Specifically, in this embodiment, a shut-off valve is installed on the pipeline between the waste gas treatment mechanism 500 and the heat exchange mechanism 240. The flow direction of the medium is switched by the opening and closing state of the shut-off valve, thereby realizing the path switching logic of closing under normal pressure sealing conditions and opening under overpressure relief conditions.

[0081] It should be noted that, since the exhaust gas treatment unit 500 is in long-term contact with corrosive hydrogen-containing exhaust gases containing chlorosilanes and hydrogen chloride, it can be made of stainless steel, carbon steel with an anti-corrosion lining, fiberglass, or polypropylene composite materials to meet the requirements for long-term corrosion-resistant operation.

[0082] In one possible embodiment, the sealing system for polysilicon production further includes at least one regulating valve 600, which is disposed between the reflux mechanism 230 and the heat exchange mechanism 240, for regulating the gas pressure of the gaseous medium in the separation mechanism 210.

[0083] And / or, the regulating valve 600 is disposed between the heat exchange mechanism 240 and the waste gas treatment mechanism 500, for regulating the gas pressure of the sealing gas in the second condensation mechanism 250.

[0084] The regulating valve 600, located between the reflux mechanism 230 and the heat exchange mechanism 240, can adjust the flow rate of the gaseous medium entering the heat exchange mechanism 240, thereby stabilizing the gas pressure of the gaseous medium inside the separation mechanism 210 and suppressing pressure fluctuations inside the separation mechanism 210.

[0085] The regulating valve 600, located between the heat exchange mechanism 240 and the exhaust gas treatment mechanism 500, can control the flow rate of the exhaust gas discharged into the exhaust gas treatment mechanism 500, maintain the stable pressure of the sealing gas inside the second condensation mechanism 250, and ensure the stable pressure of the sealing gas delivered to the outside.

[0086] Specifically, in this embodiment, the regulating valve 600 is a pneumatic pressure regulating valve, which has a fast response speed and is suitable for the needs of process automation control; in other embodiments, the regulating valve 600 may also be a self-operated pressure regulating valve or an electric regulating valve, so as to meet the usage requirements of different control schemes.

[0087] It should be understood that as long as the regulating valve 600 can regulate the air pressure inside the corresponding mechanism, this application does not impose too many restrictions on the specific structure of the regulating valve 600.

[0088] In one possible embodiment, the sealing system for polysilicon production further includes a control mechanism 10, a first pressure sensor 20, and a second pressure sensor 30. The detection end of the first pressure sensor 20 is located in the separation mechanism 210, and the detection end of the second pressure sensor 30 is located in the second condensation mechanism 250. The control mechanism 10 is communicatively connected to the first pressure sensor 20 and the second pressure sensor 30 and is capable of controlling the operation of the regulating valve 600.

[0089] The system employs a first pressure sensor 20 to collect real-time pressure signals of the gas phase inside the separation mechanism 210, and a second pressure sensor 30 to collect real-time pressure signals of the sealing gas inside the second condensation mechanism 250. These pressure signals are transmitted to the control mechanism 10. The control mechanism 10 outputs control commands based on the pressure detection signals, driving the corresponding regulating valve 600 to adjust its opening, thereby stabilizing the internal pressures of the separation mechanism 210 and the second condensation mechanism 250. This configuration enhances the automation level of system pressure control and reduces pressure fluctuations caused by manual operation.

[0090] Specifically, in this embodiment, the pressure sensors (i.e., the first pressure sensor 20 and the second pressure sensor 30) can be remote pressure transmitters, which can continuously output standard electrical signals to facilitate signal interfacing with the control mechanism 10; in other embodiments, the pressure sensors can also be intelligent pressure sensors, which have on-site display and local signal output functions.

[0091] In addition, the control mechanism 10 can be a PLC control system or a microcontroller, as long as it can achieve the above-mentioned automatic control. No further restrictions are placed on the specific structure of the control mechanism 10.

[0092] It should be understood that as long as the pressure sensor can continuously collect the internal pressure of the corresponding mechanism and transmit the detection signal to the control mechanism 10, this application does not impose too many restrictions on the specific type of pressure sensor.

[0093] In one possible embodiment, the output end of the heat exchange mechanism 240 includes a second liquid outlet pipe 241 and a second gas outlet pipe 242. The second liquid outlet pipe 241 is connected to the second condensing mechanism 250. The separation device 200 also includes a third condensing mechanism 260. The second gas outlet pipe 242 is connected to the second condensing mechanism 250 through the third condensing mechanism 260.

[0094] The gas-liquid mixture output by the heat exchange mechanism 240 is transported through two independent channels via the second liquid outlet pipe 241 and the second gas outlet pipe 242.

[0095] The second liquid outlet pipe 241 is used to directly transport the liquid medium produced by the heat exchange mechanism 240 to the second condensation mechanism 250; the second gas outlet pipe 242 transports the gas medium produced by the heat exchange mechanism 240 to the third condensation mechanism 260.

[0096] Specifically, the third condensation unit 260 can perform deep condensation treatment on the incoming gaseous medium, causing all chlorosilane components in the gaseous medium to condense and liquefy, completely removing condensable components from the gas phase. The medium processed by the third condensation unit 260 is uniformly sent to the second condensation unit 250 to complete gas-liquid separation. Finally, a hydrogen-containing non-condensable gas is formed at the top of the second condensation unit 250, which is mainly composed of hydrogen, contains trace amounts of hydrogen chloride, and has no remaining condensable chlorosilane components. This effectively purifies the sealing gas and removes the chlorosilane components entrained in the gas phase.

[0097] Specifically, in this embodiment, the third condensation mechanism 260 adopts a -45°C cryogenic cooler, which can achieve complete condensation and removal of chlorosilane components in the gas phase to obtain high-purity hydrogen-containing non-condensable gas. In other embodiments, the third condensation mechanism 260 can also be a plate-fin condenser or a coil condenser, which can also achieve the above functions. The specific structure of the third condensation mechanism 260 is not limited here.

[0098] It should be noted that the second liquid outlet pipe 241, the second gas outlet pipe 242, and the third condensation mechanism 260 are in long-term contact with the corrosive medium of chlorosilane, and the third condensation mechanism 260 is in a long-term low-temperature cryogenic condition. The materials of the above components can be stainless steel, carbon steel lined with PTFE, titanium alloy, and other low-temperature and corrosion-resistant materials to meet the requirements of medium sealing and corrosion prevention operation.

[0099] In one possible embodiment, the separation device 200 further includes an outlet pump 700 and a receiving tank 800, with the input end of the outlet pump 700 connected to the second condensation mechanism 250 and the output end of the outlet pump 700 connected to the receiving tank 800.

[0100] The liquid discharge pump 700 can deliver the liquid medium accumulated inside the second condensation unit 250, regulate the liquid level inside the second condensation unit 250, prevent the liquid medium from accumulating and affecting the gas-liquid separation effect, and reduce the phenomenon of liquid medium being entrained by the gas phase. The receiving tank 800 can receive the liquid medium delivered by the liquid discharge pump 700, realize the centralized temporary storage of liquid materials, and facilitate the subsequent recovery or centralized treatment of the liquid medium.

[0101] Specifically, in this embodiment, the liquid outlet pump 700 is a magnetic pump, which has excellent sealing performance and is suitable for conveying chlorosilane media. In other embodiments, the liquid outlet pump 700 can also be a diaphragm pump or a centrifugal pump. As long as the liquid outlet pump 700 can convey liquid media, this application does not impose too many restrictions on the specific pump type of the liquid outlet pump 700.

[0102] In one possible embodiment, the storage tank 800 is a vertical buffer tank, which can provide space for liquid phase buffering and reduce the fluctuations in operating conditions caused by frequent start-stop of the liquid discharge pump 700. In another possible embodiment, the storage tank 800 can be a horizontal tank, which can also achieve the above functions. No specific restrictions are placed on the specific structure of the storage tank 800 here.

[0103] In one possible embodiment, a shut-off valve and a check valve may be installed between the liquid discharge pump 700 and the second condensation mechanism 250, and between the liquid discharge pump 700 and the receiving tank 800, to facilitate maintenance and isolation, and to prevent backflow of the liquid medium.

[0104] In one possible embodiment, the sealing system for polysilicon production also includes an emergency mechanism 900, the output of which is optionally connected to a balance branch pipe 400 for introducing emergency gas into the storage tank 100 via the balance branch pipe 400.

[0105] The emergency mechanism 900 serves as a backup gas supply unit for the sealing gas. When the separation unit 200 experiences a gas source failure, shutdown, or insufficient gas supply pressure, the emergency mechanism 900 can supply emergency gas to the balancing branch pipe 400 and then into the storage tank 100 to continuously maintain a slight positive pressure inside the storage tank 100, preventing backflow of external air and mitigating safety risks such as chlorosilane hydrolysis and equipment corrosion. Moreover, the emergency mechanism 900 is independently connected to the balancing branch pipe 400, allowing it to replenish gas to one or more storage tanks 100. It is isolated from the main gas supply path, enabling switching between normal sealing operation and emergency gas replenishment operation.

[0106] Specifically, in this embodiment, the emergency response mechanism 900 uses a nitrogen manifold gas supply unit; in other embodiments, the emergency response mechanism 900 may also use a liquid nitrogen vaporization gas supply device or a mobile inert gas source device. As long as the emergency response mechanism 900 can provide emergency gas supply, this application does not impose too many restrictions on the equipment form of the emergency response mechanism 900.

[0107] In one possible embodiment, a pneumatic switching valve and a check valve may be provided between the output end of the emergency mechanism 900 and the balance branch pipe 400 to control the pipeline opening and closing and prevent the chlorosilane gaseous medium in the storage tank 100 from flowing back into the emergency mechanism 900.

[0108] It should be noted that inert gases such as nitrogen or argon can be used as emergency gas. Since inert gases do not react with the chlorosilane medium inside the tank, emergency pressure sealing can be achieved.

[0109] It should be noted that the optional connection methods between various mechanisms and pipelines in this application can all be achieved by using shut-off valves, regulating valves or pneumatic switching valves to open and close the passage, thereby realizing the switching of medium flow direction, pipeline on / off control and operating condition switching adjustment. Moreover, those skilled in the art can make adjustments according to actual operating conditions, which will not be elaborated on here.

[0110] In one possible embodiment, an industrial application scenario for a polysilicon plant is provided, which uses the sealing and compression system for polysilicon production of this embodiment.

[0111] The main balancing pipe 300 is made of DN100 carbon steel corrosion-resistant pipe to meet the total flow load of the pressurized gas. Each balancing branch pipe 400 is made of DN25 to DN40 carbon steel corrosion-resistant pipe, matched to the volume of the corresponding storage tank 100 and the gas phase evaporation load. Before commissioning, both the main balancing pipe 300 and the balancing branch pipes 400 undergo overall pressure testing and nitrogen purging to remove residual impurities and air from the pipelines, ensuring reliable sealing performance of the entire gas phase pipeline network, free from impurity interference, and meeting the requirements for corrosion protection and airtight operation of chlorosilane media.

[0112] Under the stable operation of the coarse separator at full load, the second condenser 250 continuously maintains deep cooling operation at -45℃, thereby completing gas-liquid separation of the mixed gas after multi-stage condensation, and stably producing dry, non-condensable hydrogen-containing gas without liquid entrainment, which is used as the sealing gas.

[0113] The reflux mechanism 230 and the heat exchange mechanism 240 are connected by a self-regulating pressure regulating valve to maintain the pressure of the sealing gas output from the second condensation mechanism 250 at a constant 1.9 barG. This keeps the first gas pressure inside each storage tank 100 stable at 1.9 barG, so that the system can establish a complete gas phase closed-loop circulation loop. The gas phase medium volatilized from the storage tank 100 can be returned to the separation device 200 along the balance branch pipe 400 and the balance main pipe 300. There is no continuous gas phase external emission throughout the process, achieving steady-state closed-loop sealing operation.

[0114] During the transitional operating conditions of system startup and temperature rise followed by shutdown for maintenance, the separator 200 cannot continuously and stably produce qualified dry sealing gas. At this time, the shut-off valve between the balance main pipe 300 and the second condensation mechanism 250 is closed, while the pneumatic switching valve between the emergency mechanism 900 and the balance branch pipe 400 is opened. The emergency mechanism 900 then supplies emergency gas to each storage tank 100 to maintain a slightly positive pressure sealing state inside the storage tank 100, ensuring equipment safety during the transitional operating conditions.

[0115] Once the system is stable and the second condensation mechanism 250 can stably produce qualified sealing gas, the emergency mechanism 900 is gradually shut down, and the sealing gas continues to be introduced into the storage tank 100 through the separation device 200.

[0116] When the system is in a long-term shutdown and maintenance condition, the shut-off valves of the connecting pipelines at both ends of the balance main pipe 300 are closed, and the stable micro-positive pressure inside the storage tank 100 is maintained solely through the emergency mechanism 900 to prevent outside air from entering the storage tank 100 and to prevent hydrolysis of chlorosilane media and corrosion and scaling of equipment.

[0117] like Figure 2 As shown, this application embodiment also provides a sealing method for polysilicon production, using the aforementioned sealing system for polysilicon production, including:

[0118] Sealing gas is prepared by separation device 200.

[0119] Specifically, the separation unit 210 can output a gaseous medium containing hydrogen, gaseous chlorosilane, and hydrogen chloride, and transport the gaseous medium to the first condensation unit 220 for cooling and condensation. The condensed liquid chlorosilane is transported to the reflux unit 230 through the first liquid outlet pipe 221, and the uncondensed gaseous medium is transported to the reflux unit 230 through the first gas outlet pipe 222.

[0120] The reflux mechanism 230 can receive gas-liquid two-phase media, wherein the liquid chlorosilane can be refluxed to the separation mechanism 210 for repurification, and the uncondensed gas-phase media can be transported to the heat exchange mechanism 240 for pre-cooling operation through the reflux mechanism 230.

[0121] The medium output by the heat exchange mechanism 240 includes both liquid and gas phases. The liquid phase medium produced by the heat exchange mechanism 240 is transported to the second condensation mechanism 250 through the second liquid outlet pipe 241, and the gas phase medium produced by the heat exchange mechanism 240 is transported to the third condensation mechanism 260 through the second gas outlet pipe 242. The third condensation mechanism 260 performs deep condensation on the gas phase medium, so that all the chlorosilanes in it are liquefied.

[0122] The medium processed by the third condensation unit 260 is sent to the second condensation unit 250 to complete gas-liquid separation, thereby obtaining a hydrogen-containing non-condensable gas that is mainly hydrogen, contains trace amounts of hydrogen chloride, and has no condensable chlorosilane components, which is then used as a sealing gas.

[0123] The liquid medium collected inside the second condensation unit 250 can be transported to the collection tank 800 by the liquid discharge pump 700 for centralized temporary storage. By timely discharge of the liquid medium, the accumulation of liquid can be avoided, which would affect the gas-liquid separation effect and improve the recovery rate of chlorosilane.

[0124] As can be seen, the above steps can remove chlorosilane components from the gas phase through multi-stage condensation, thereby obtaining a clean and stable sealing gas source.

[0125] The pressure-sealing gas is introduced into the storage tank 100 through the main balance pipe 300 and the branch balance pipe 400, so that the second pressure of the pressure-sealing gas is equal to the first pressure of the storage medium in the storage tank 100.

[0126] Specifically, the sealing gas produced by the second condensation mechanism 250 is sent out through the third outlet 251 and sequentially transported to each storage tank 100 through the balance main pipe 300 and the balance branch pipe 400. By setting the regulating valve 600, the second gas pressure of the sealing gas is kept consistent with the first gas pressure of the storage medium inside the storage tank 100. This not only eliminates the need for continuous gas replenishment and frequent venting, reducing material and energy consumption, but also prevents backflow of external air from causing hydrolytic corrosion of chlorosilanes, thus improving the safety of system operation.

[0127] More specifically, under normal operating conditions, the sealing gas output by the second condensing mechanism 250 can be completely delivered to the balance main pipe 300 for sealing the storage tank 100; when the pressure inside the second condensing mechanism 250 is higher than the preset safety pressure threshold, it is determined that the system has overpressured, and the hydrogen-containing non-condensable gas output by the second condensing mechanism 250 is delivered to the waste gas treatment mechanism 500 through the pipeline for harmless treatment.

[0128] When the separation device 200 malfunctions or the gas supply pressure is insufficient, the emergency mechanism 900 can supply inert emergency gas to the storage tank 100 through the balance branch pipe 400 to continuously maintain a slight positive pressure inside the tank. Through the above steps, the safe operation of the storage tank 100 under abnormal operating conditions is ensured.

[0129] The volatile medium stored in the storage tank 100 can be returned to the separation device 200 through the balance branch pipe 400 and the balance main pipe 300.

[0130] Specifically, the storage medium stored inside the storage tank 100 includes at least one or more of trichlorosilane, silicon tetrachloride, and dichlorosilane, which can volatilize to form a gaseous volatile medium. Under the action of gas pressure balance, the volatile medium is sequentially transported back to the separation mechanism 210 through the balance branch pipe 400 and the balance main pipe 300 in reverse direction, and re-participates in the separation, condensation and recovery process, so as to realize the recycling of chlorosilane materials, reduce material venting loss, and construct a gas phase circulation path.

[0131] It should be understood that, through the above settings, fresh hydrogen is no longer continuously consumed under normal production conditions, and the continuous hydrogen venting operation is eliminated, reducing the risk of flammable and explosive gas emissions from the tank area and lowering safety hazards caused by pipeline and valve leaks; the total amount of waste gas received by the waste gas treatment unit 500 is reduced, thereby reducing material consumption and equipment operating load.

[0132] During the above process, the first pressure sensor 20 can collect the pressure signal inside the separation mechanism 210, the second pressure sensor 30 can collect the pressure signal inside the second condensation mechanism 250, and the control mechanism 10 can adjust the regulating valve 600 according to the pressure signal to stabilize the internal pressure of the separation mechanism 210 and the second condensation mechanism 250.

[0133] The embodiments or implementation methods in this application are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0134] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0135] In the description of this application, it should be understood that the terms “comprising” and “having” as used herein, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, display structure, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may include other steps or units that are not expressly listed or that are inherent to such process, method, product, or device.

[0136] The term "and / or" used in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0137] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A sealing and compression system for polycrystalline silicon production, characterized in that, include: Multiple storage tanks (100) are used to store storage media with a pressure value of a first atmosphere; A separation device (200) is used to output a sealing gas with a pressure value of a second pressure, wherein the first pressure and the second pressure are equal; A balance main pipe (300), the first air inlet (310) of which is optionally connected to the output end of the separation device (200); Multiple balance branch pipes (400) and multiple storage tanks (100) are selectively connected to the first outlet (320) of the balance main pipe (300) via the balance branch pipes (400).

2. The sealing and compression system for polycrystalline silicon production according to claim 1, characterized in that, The separation device (200) includes a separation mechanism (210), a first condensation mechanism (220) and a reflux mechanism (230). The separation mechanism (210) is used to output a gaseous medium to the first condensation mechanism (220), and the output end of the first condensation mechanism (220) is connected to the reflux mechanism (230).

3. The sealing and compression system for polycrystalline silicon production according to claim 2, characterized in that, The output end of the first condensation mechanism (220) includes a first liquid outlet pipe (221) and a first gas outlet pipe (222). The first liquid outlet pipe (221) can be connected to the separation mechanism (210) through the reflux mechanism (230), and the first gas outlet pipe (222) is connected to the reflux mechanism (230).

4. The sealing and compression system for polycrystalline silicon production according to claim 2, characterized in that, The separation device (200) further includes a heat exchange mechanism (240) and a second condensation mechanism (250). The input end of the heat exchange mechanism (240) is selectively connected to the second outlet end (231) of the reflux mechanism (230), and the output end of the heat exchange mechanism (240) is connected to the second condensation mechanism (250). The third outlet end (251) of the second condensation mechanism (250) is connected to the first inlet end (310) of the balance main pipe (300) for outputting the sealing gas.

5. The sealing and compression system for polycrystalline silicon production according to claim 4, characterized in that, It also includes an exhaust gas treatment mechanism (500), wherein the third outlet (251) of the second condensation mechanism (250) can be selectively connected to the second inlet (510) of the exhaust gas treatment mechanism (500) via the heat exchange mechanism (240).

6. The sealing and compression system for polycrystalline silicon production according to claim 5, characterized in that, It also includes at least one regulating valve (600), which is disposed between the reflux mechanism (230) and the heat exchange mechanism (240) for regulating the gas pressure of the gaseous medium in the separation mechanism (210); And / or, the regulating valve (600) is disposed between the heat exchange mechanism (240) and the waste gas treatment mechanism (500) for regulating the pressure of the sealing gas in the second condensation mechanism (250).

7. The sealing and compression system for polycrystalline silicon production according to claim 4, characterized in that, The output end of the heat exchange mechanism (240) includes a second liquid outlet pipe (241) and a second gas outlet pipe (242). The second liquid outlet pipe (241) is connected to the second condensing mechanism (250). The separation device (200) also includes a third condensing mechanism (260). The second gas outlet pipe (242) is connected to the second condensing mechanism (250) through the third condensing mechanism (260).

8. The sealing and compression system for polycrystalline silicon production according to claim 7, characterized in that, The separation device (200) further includes a liquid discharge pump (700) and a collection tank (800), the input end of the liquid discharge pump (700) being connected to the second condensation mechanism (250), and the output end of the liquid discharge pump (700) being connected to the collection tank (800).

9. The sealing system for polycrystalline silicon production according to any one of claims 1-8, characterized in that, It also includes an emergency mechanism (900), the output of which is optionally connected to the balance branch pipe (400) for introducing emergency gas into the storage tank (100) through the balance branch pipe (400).

10. A sealing method for polycrystalline silicon production, characterized in that, Using the sealing system for polysilicon production according to any one of claims 1-9, comprising: The sealing gas is prepared by the separation device (200); The pressure-sealing gas is introduced into the storage tank (100) through the balance main pipe (300) and the balance branch pipe (400) so that the second pressure of the pressure-sealing gas is equal to the first pressure of the storage medium in the storage tank (100); The volatile medium stored in the storage tank (100) can be returned to the separation device (200) through the balance branch pipe (400) and the balance main pipe (300).

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