Bleed gas recycling system for polycrystalline silicon production

Abstract

The utility model provides a bleed gas recycling system for polycrystalline silicon production, which relates to the technical field of polycrystalline silicon production and comprises a buffer tank group for providing materials; the feeding tank group comprises a first feeding tank and a second feeding tank, and the first feeding tank and the second feeding tank are both communicated with the buffer tank group and are used for receiving materials; a first communicating port is formed in the first feeding tank, a second communicating port is formed in the second feeding tank, and a first communicating pipe is communicated between the first communicating port and the second communicating port; the first valve is arranged on the first communicating pipe; the first communicating pipe is further provided with an adjusting valve set located between the first valve and the second feeding tank, and the adjusting valve set is used for adjusting the opening and closing state of the first communicating pipe. According to the device, pressurized hydrogen can be recycled, the use amount of the pressurized hydrogen is reduced, silicon powder particles in discharged gas are recycled, the leaching load of tail gas is effectively reduced, and tail gas emission is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon production, in particular to a vented gas recycling system for polysilicon production. Background Art

[0002] The process currently used in polysilicon production is mainly the "modified Siemens method". Under this method, a large amount of vented gas will be generated in the silicon powder feeding unit of the cold hydrogenation section during the production process. In the cold hydrogenation section, the feeding of silicon powder is an intermittent process, which requires repeated unloading and pressure relief, and it is impossible to eliminate the generation of vented gas. In this process, the following problems often occur: 1. When the silicon powder feed tank is pressurized, a large amount of high-pressure hydrogen is consumed; 2. When the silicon powder feed tank is depressurized to the silicon powder filter, a large amount of silicon powder is discharged, and the operation is risky, and fine-particle silicon powder is wasted; 3. The vented gas generated in the silicon powder feeding process is eventually discharged into the tail gas washing for alkaline washing, hydrolysis, and neutralization operations, which will result in the consumption of a large amount of alkaline solution. Utility Model Content

[0003] In order to solve the problems of large-scale consumption of high-pressure hydrogen and alkali solution in the cold hydrogenation section, as well as high operational risks caused by large discharge of silicon powder, the utility model provides a vented gas recycling system for polysilicon production, which can realize the recycling of pressurized hydrogen, reduce the amount of pressurized hydrogen and simultaneously recycle the silicon powder particles in the vented gas, so as to effectively reduce the tail gas elution load and reduce tail gas emissions.

[0004] The technical solution adopted in this utility model is:

[0005] Provided is a vent gas recycling system for polysilicon production, comprising:

[0006] A buffer tank group is used to provide materials; a feed tank group includes a first feed tank and a second feed tank, the first feed tank and the second feed tank are both connected to the buffer tank group for receiving materials; a first connecting port is provided on the first feed tank, a second connecting port is provided on the second feed tank, and a first connecting pipe is connected between the first connecting port and the second connecting port; a first valve is arranged on the first connecting pipe; the first connecting pipe is also provided with a regulating valve group located between the first valve and the second feed tank, which is used to adjust the opening and closing state of the first connecting pipe.

[0007] In some embodiments of the present invention, the regulating valve group includes a first regulating valve, a front hand valve, a rear hand valve, a bypass hand valve and a connecting branch pipe, the first regulating valve is arranged on the connecting pipe, the front hand valve is arranged on the connecting pipe between the first valve and the first regulating valve, and the rear hand valve is arranged on the connecting pipe between the first valve and the second feed tank; one end of the connecting branch pipe is connected to the connecting pipe between the front hand valve and the first valve, and the other end is connected to the connecting pipe between the rear hand valve and the second feed tank, and the bypass hand valve is arranged on the connecting branch pipe.

[0008] In some embodiments of the present invention, the buffer tank group includes a first buffer tank, a second buffer tank, a second connecting pipe, a third connecting pipe, a fourth connecting pipe, a second valve, a third valve, a fourth valve and a fifth valve. The second connecting pipe is respectively connected to the feed port of the first buffer tank and the feed port of the second buffer tank, the third connecting pipe is respectively connected to the discharge port of the first buffer tank and the feed port of the first feed tank, and the fourth connecting pipe is respectively connected to the discharge port of the second buffer tank and the feed port of the second feed tank; the second valve and the third valve are both arranged on the second connecting pipe, the second valve is used to control the material entering the first buffer tank, and the third valve is used to control the material entering the second buffer tank; the fourth valve is arranged on the third connecting pipe, and the fifth valve is arranged on the fourth connecting pipe.

[0009] In some embodiments of the present invention, a first connecting pipe is provided on the connecting pipe between the first valve and the first feed tank, and a second connecting pipe is provided on the connecting pipe between the regulating valve group and the second feed tank; a first pressure relief filter is provided at the other end of the first connecting pipe, and a second pressure relief filter is provided at the other end of the second connecting pipe; a sixth valve is provided on the first connecting pipe, and a seventh valve is provided on the second connecting pipe.

[0010] In some embodiments of the present invention, a fifth connecting pipe is connected between the first pressure relief filter and the second pressure relief filter, and at least two second regulating valves are provided on the fifth connecting pipe, which are used to control the pressure relief pressure of the first pressure relief filter and the second pressure relief filter respectively.

[0011] In some embodiments of the present invention, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve and the seventh valve are all cut-off valves.

[0012] The beneficial effects of the utility model are:

[0013] The buffer tank group is used to transport materials to the first feed tank and the second feed tank in the feed tank group. When the material level in the first feed tank is high and the feeding has been completed, and the material level in the second feed tank is low and needs to be fed, the material transported to the first feed tank and the second feed tank by the buffer tank group is first closed, and then the first valve on the first connecting pipe between the first feed tank and the second feed tank is opened, and then the regulating valve group on the first connecting pipe is opened and the opening is adjusted, so that the bleed gas discharged from the second feed tank can enter the first feed tank through the first connecting pipe, so as to achieve the effect of recycling the bleed gas, reduce the amount of pressurized hydrogen required in the first feed tank, and reuse the silicon powder particles in the bleed gas, reduce energy consumption, and also reduce the final tail gas leaching treatment load for the first feed tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 This is a flow diagram of the vent gas recycling system for polysilicon production;

[0016] Figure 2 A schematic diagram of a process for activating the first regulating valve;

[0017] Figure 3 This is a flow chart for activating the bypass manual valve;

[0018] Figure 4 This is a flow chart after closing the first valve and regulating valve group.

[0019] Reference numerals:

[0020] 1-first buffer tank, 2-second buffer tank, 3-first feed tank, 4-second feed tank, 5-feeding pipe, 6-first connecting pipe, 7-second connecting pipe, 8-third connecting pipe, 9-fourth connecting pipe, 10-first connecting pipe, 11-second connecting pipe, 12-connecting branch pipe, 13-first valve, 14-first regulating valve, 15-front hand valve, 16-rear hand valve, 17-bypass hand valve, 18-first pressure relief filter, 19-second pressure relief filter, 20-second valve, 21-third valve, 22-fourth valve, 23-fifth valve, 24-sixth valve, 25-seventh valve, 26-fifth connecting pipe, 27-second regulating valve, 28-air release line. DETAILED DESCRIPTION

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0022] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention.

[0023] The embodiments of the utility model are described in detail below with reference to the accompanying drawings.

[0024] Example

[0025] like Figure 1 As shown, this embodiment provides a bleed gas recycling system for polysilicon production, comprising:

[0026] Buffer tank group, used to provide materials;

[0027] A feed tank group includes a first feed tank 3 and a second feed tank 4. The first feed tank 3 and the second feed tank 4 are both connected to the buffer tank group for receiving materials. A first connecting port is provided on the first feed tank 3, and a second connecting port is provided on the second feed tank 4. A first connecting pipe 6 is connected between the first connecting port and the second connecting port.

[0028] The first valve 13 is provided on the first connecting pipe 6 ; the first connecting pipe 6 is also provided with a regulating valve group located between the first valve 13 and the second feed tank 4 , which is used to adjust the opening and closing state of the first connecting pipe 6 .

[0029] In this embodiment, the buffer tank group is connected to the external feed pipe 5, and the feed pipe 5 transports the material to the buffer tank group for temporary storage. The first feed tank 3 and the second feed tank 4 are respectively connected to the buffer tank group, so that the materials temporarily stored in the buffer tank group can enter the first feed tank 3 and the second feed tank 4 for use. A first connecting port is provided on the first feed tank 3, and a second connecting port is provided on the second feed tank 4. The first connecting port and the second connecting port are connected to each other by setting a first connecting pipe 6. A first valve 13 and a regulating valve group are provided on the first connecting pipe 6 to control the flow of discharge gas between the first feed tank 3 and the second feed tank 4.

[0030] During use, when the material level in the first feed tank 3 is high and the feeding has been completed, the first feed tank 3 is now in a state of preparing for pressure charging, and then when the material level in the second feed tank 4 is low and feeding is required, the second feed tank 4 is now in a state of preparing for pressure relief. Then close the connection between the buffer tank group and the first feed tank 3 and the second feed tank 4 to prevent the buffer tank group from continuing to feed the first feed tank 3 and the second feed tank 4, and then open the first valve 13 on the first connecting pipe 6, and then open the regulating valve group, so that the first feed tank 3 and the second feed tank 4 are connected through the first connecting pipe 6. At this time, due to the high pressure in the second feed tank 4, the gas in the tank after use will be input from the second connecting port, that is, the gas will be released, and the released gas will enter the first connecting pipe 6, it passes through the regulating valve group and the first valve 13 in sequence, and finally enters the interior of the first feed tank 3 from the first connecting port on the first feed tank 3. After the released gas enters the interior of the first feed tank 3, the first feed tank 3 is immediately pressurized, and the released gas can continue to be used for reaction in the first feed tank 3. After the tank pressure in the first feed tank 3 reaches 1.5Mpa, the first valve 13 is closed first, and then the regulating valve group is closed to disconnect the connecting pipeline between the first feed tank 3 and the second feed tank 4. Finally, the operation is continued according to the pressure values on the first feed tank 3 and the second feed tank 4. Under the conditions adopted in this embodiment, the first feed tank 3 will continue to be pressurized with high-pressure hydrogen until the value reaches 2.75-2.80Mpa, and then the connection between the buffer tank group and the first feed tank 3 can be opened to realize the feeding of the first feed tank 3; the pressure inside the second feed tank 4 will still be relatively large, and it is necessary to continue to discharge the gas by connecting other pipelines to make the pressure inside the second feed tank 4 at normal pressure, and then the connection between the buffer tank group and the second feed tank 4 can be restored, so that the buffer tank group can continue to feed the second feed tank 4. This process is a complete one-time discharge gas reuse cycle.

[0031] Further, such as Figure 1-3 As shown, the regulating valve group includes a first regulating valve 14, a front hand valve 15, a rear hand valve 16, a bypass hand valve 17 and a connecting branch pipe 12. The first regulating valve 14 is arranged on the connecting pipe, the front hand valve 15 is arranged on the connecting pipe between the first valve 13 and the first regulating valve 14, and the rear hand valve 16 is arranged on the connecting pipe between the first valve 13 and the second feed tank 4; one end of the connecting branch pipe 12 is connected to the connecting pipe between the front hand valve 15 and the first valve 13, and the other end is connected to the connecting pipe between the rear hand valve 16 and the second feed tank 4, and the bypass hand valve 17 is arranged on the connecting branch pipe 12.

[0032] In the regulating valve assembly, the first regulating valve 14, the front hand valve 15, and the rear hand valve 16 located on the first connecting pipe 6 form a parallel circuit with the bypass hand valve 17. When the second feed tank 4 discharges bleed gas through the first connecting pipe 6, the opening of the first regulating valve 14 is adjusted between 10% and 30%, and the pressure rate from the first connecting pipe 6 to the first feed tank 3 is ≤50 kPa / s. If the first regulating valve 14 malfunctions, the front hand valve 15 and the rear hand valve 16 at both ends of the first regulating valve 14 are closed, preventing the second feed tank 4 from continuing to flow through the connected second connecting pipe 7. Instead, the flow is diverted to the connecting branch pipe 12 connected in parallel with the first connecting pipe 6. Opening the bypass hand valve 17 on the connecting branch pipe 12 allows the material from the second feed tank 4 to pass through, and the pressure relief rate from the second feed tank 4 into the first connecting pipe 6 can be adjusted using the bypass hand valve 17.

[0033] During use, when the material level in the second feed tank 4 is low and needs to be fed, the second feed tank 4 is in a state of preparing to relieve pressure, and the discharged gas in the second feed tank 4 is input into the first connecting pipe 6; at the same time, the material level in the first feed tank 3 is high, and the feeding is completed, that is, the fourth valve 22 is closed, preventing the first buffer tank 1 from continuing to transport materials to the first feed tank 3. Similarly, the second buffer tank 2 will not continue to transport materials to the interior of the second feed tank 4. The second feed tank 4 discharges the vent gas used inside itself into the first connecting pipe 6, and the first valve 13 and the regulating valve group control the gas charging rate and gas charging amount entering the first feed tank 3, and the regulating valve group has two passages, one of which is the passage on the first connecting pipe 6, and the other is the passage connected in parallel with the first connecting pipe 6. When the first regulating valve 14 fails, the front hand valve 15 and the rear hand valve 16 can be closed to disconnect the passage on the connecting pipe and stop transporting materials, and then the bypass hand valve 17 on the connecting branch pipe 12 can be opened to allow the material transported by the second feed tank 4 to be transported through the connecting branch pipe 12, and the first regulating valve 14 on the first connecting pipe 6 can be removed for maintenance.

[0034] Further, such as Figure 1-4As shown, the buffer tank group includes a first buffer tank 1, a second buffer tank 2, a second connecting pipe 7, a third connecting pipe 8, a fourth connecting pipe 9, a second valve 20, a third valve 21, a fourth valve 22 and a fifth valve 23. The second connecting pipe 7 is respectively connected to the feed port of the first buffer tank 1 and the feed port of the second buffer tank 2, the third connecting pipe 8 is respectively connected to the discharge port of the first buffer tank 1 and the feed port of the first feed tank 3, and the fourth connecting pipe 9 is respectively connected to the discharge port of the second buffer tank 2 and the feed port of the second feed tank 4; the second valve 20 and the third valve 21 are both provided on the second connecting pipe 7, the second valve 20 is used to control the material entering the first buffer tank 1, and the third valve 21 is used to control the material entering the second buffer tank 2; the fourth valve 22 is provided on the third connecting pipe 8, and the fifth valve 23 is provided on the fourth connecting pipe 9.

[0035] The first buffer tank 1 and the second buffer tank 2 are used to temporarily store silicon powder. Both the first buffer tank 1 and the second buffer tank 2 have feed ports. A second connecting pipe 7 is provided between the feed port on the first buffer tank 1 and the feed port on the second buffer tank 2. The second connecting pipe 7 is connected to an external feed pipe 5 for feeding materials. The feed pipe 5 transports the materials to the second connecting pipe 7, and the feeding is controlled by the second valve 20 and the third valve 21 on the second connecting pipe 7. The silicon powder temporarily stored in the first buffer tank 1 and the second buffer tank 2 is transported according to the corresponding third connecting pipe 8 and the fourth connecting pipe 9. The feeding of the materials is controlled by the fourth valve 22 on the third connecting pipe 8, and by the fifth valve 23 on the fourth connecting pipe 9. When the first feed tank 3 reaches 1.5Mpa under the pressure of the bleed gas from the second feed tank 4, the pressure is increased to 2.75-2.80Mpa with high-pressure hydrogen, and the first feed tank 3 can be filled with materials by opening the fourth valve 22.

[0036] Further, such as Figure 1-4 As shown, a first connecting pipe 10 is provided on the connecting pipe between the first valve 13 and the first feed tank 3, and a second connecting pipe 11 is provided on the connecting pipe between the regulating valve group and the second feed tank 4; a first pressure relief filter 18 is provided at the other end of the first connecting pipe 10, and a second pressure relief filter 19 is provided at the other end of the second connecting pipe 11; a sixth valve 24 is provided on the first connecting pipe 10, and a seventh valve 25 is provided on the second connecting pipe 11.

[0037] The first connecting pipe 6 located between the first valve 13 and the first feed tank 3 is connected to the first connecting pipe 10. The first connecting pipe 10 is used to transport the discharged gas to the first pressure relief filter 18 connected to the other end of the first connecting pipe 10 for filtering the discharged gas when the first feed tank 3 needs to discharge gas; the second connecting pipe 7 located between the second valve 20 and the second feed tank 4 is connected to the second connecting pipe 11. The second connecting pipe 11 is used as a discharge channel when the second feed tank 4 needs to discharge gas again after the second feed tank 4 completes the pressurization of the discharged gas from the first feed tank 3, and transports the discharged gas to the second pressure relief filter 19 connected to the other end of the second connecting pipe 11 for filtering the discharged gas.

[0038] During use, when the second feed tank 4 pressurizes the first feed tank 3 with discharge gas, the first pressure relief filter 18 on the first connecting pipe 10 and the second pressure relief filter 19 on the second connecting pipe 11 are closed to prevent the discharge gas required by the first feed tank 3 from being discharged through the first pressure relief filter 18 and the second pressure relief filter 19 respectively. After the required discharge gas in the first feed pipe reaches the appropriate air pressure, the first valve 13 and the regulating valve group on the first connecting pipe 6 are closed. At this time, the tank internal pressures of the first feed tank 3 and the second feed tank 4 need to be adjusted. For example, the tank internal pressure of the first feed tank 3 is too low, and high-pressure hydrogen is required for pressure replenishment. After the pressure in the first feed tank 3 stabilizes, after a period of treatment and use, the gas retained in the first feed tank 3 needs to be discharged through the first connecting pipe 10 connected to the first connecting pipe 6, and filtered by the first pressure relief filter 18 connected to the other end of the first connecting pipe 10; the tank internal pressure of the second feed tank 4 is too high, and at this time, the seventh valve 25 on the second connecting pipe 11 needs to be opened, so that the second feed tank 4 can continue to transport the discharge gas through the first connecting pipe 6 to the second connecting pipe 11, and filter it through the second pressure relief filter 19 connected to the other end of the second connecting pipe 11, so as to achieve the effect of purifying the discharge gas.

[0039] Further, such as Figure 1-4 As shown, a fifth connecting pipe 26 is connected between the first pressure relief filter 18 and the second pressure relief filter 19 , and at least two second regulating valves 27 are provided on the fifth connecting pipe 26 , which are used to control the relief pressure of the first pressure relief filter 18 and the second pressure relief filter 19 respectively.

[0040] The pressure relief filter is used to filter impurities in the pressure relief pipeline. In this embodiment, the bleed gas discharged after being recycled by the first feed tank 3, and the remaining bleed gas discharged through the second connecting pipe 11 in order to make the second feed tank 4 reach a suitable pressure state, enter the first pressure relief filter 18 and the second pressure relief filter 19 respectively to filter the silicon powder in the bleed gas to achieve the effect of purifying the bleed gas. Two second regulating valves 27 are set on the fifth connecting pipe 26 to control the pressure relief pressure of the first pressure relief filter 18 and the second pressure relief filter 19 respectively, so as to achieve the stability of the entire bleed gas recycling system. In this embodiment, a connected bleed gas pipeline is also provided on the fifth connecting pipe 26, and the connection point is located between the two second regulating valves 27. The bleed gas pipeline is used to discharge the secondary decompressed hydrogen to an external hydrogen buffer tank.

[0041] During use, after the first feed tank 3 is pressurized by the bleed gas from the second feed tank 4, the pressure inside the first feed tank 3 is 1.5 MPa. Then, high-pressure hydrogen is used to supplement the pressure of the first feed tank 3, and the tank pressure inside the first feed tank 3 is supplemented to 2.75-2.80 MPa. At this time, the first feed tank 3 can be fed. After the hydrogen supplemented in the first feed tank 3 and the gas discharged and reused from the second feed tank 4 are used up, the remaining bleed gas will be discharged through the first connecting pipe 10 connected to the first connecting pipe 6. The discharged bleed gas will be filtered through the first pressure relief filter 18 connected to the other end of the first connecting pipe 10, and the silicon powder particles in the bleed gas will be filtered out, thereby purifying the bleed gas. After the second feed tank 4 completes the recycling and pressurizing of the bleed gas from the first feed tank 3, the first valve 13 and the regulating valve group on the first connecting pipe 6 are closed. At this time, the internal pressure of the second feed tank 4 has not reached the normal value. Therefore, it is necessary to open the seventh valve 25 on the second connecting pipe 11 connected to the first connecting pipe 6 to allow the second feed tank 4 to continue to relieve pressure until the internal pressure of the second feed tank 4 is within the normal range. The bleed gas entering the second connecting pipe 11 is filtered by the second pressure relief filter 19 to remove the silicon powder particles in the bleed gas, thereby purifying the bleed gas.

[0042] Furthermore, the first valve 13 , the second valve 20 , the third valve 21 , the fourth valve 22 , the fifth valve 23 , the sixth valve 24 and the seventh valve 25 are all cut-off valves.

[0043] A shut-off valve is a type of actuator in an automated system. It consists of a multi-spring pneumatic diaphragm actuator or a floating piston actuator and a regulating valve. It receives signals from a regulating instrument and controls the shutoff, connection, or switching of fluids within corresponding pipelines. It features a simple structure, responsiveness, and reliable operation. In this embodiment, the use of a shut-off valve improves the reliability and stability of the gas release operation and reduces the number of times workers are exposed to exhaust gases when manually opening and closing the valve.

[0044] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. The embodiments and features of the embodiments of this application may be combined arbitrarily without conflict. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A vent gas recycling system for polysilicon production, characterized in that: include: A buffer tank group for providing materials; a feed tank group, the feed tank group includes a first feed tank and a second feed tank, the first feed tank and the second feed tank are both connected to the buffer tank group for receiving materials; a first connecting port is provided on the first feed tank, a second connecting port is provided on the second feed tank, and a first connecting pipe is connected between the first connecting port and the second connecting port; a first valve, the first valve is arranged on the first connecting pipe; the first connecting pipe is also provided with a regulating valve group located between the first valve and the second feed tank, for adjusting the opening and closing state of the first connecting pipe.

2. The polysilicon production bleed gas recycling system according to claim 1, characterized in that: The regulating valve group includes a first regulating valve, a front hand valve, a rear hand valve, a bypass hand valve and a connecting branch pipe. The first regulating valve is arranged on the connecting pipe, the front hand valve is arranged on the connecting pipe between the first valve and the first regulating valve, and the rear hand valve is arranged on the connecting pipe between the first valve and the second feed tank; one end of the connecting branch pipe is connected to the connecting pipe between the front hand valve and the first valve, and the other end is connected to the connecting pipe between the rear hand valve and the second feed tank, and the bypass hand valve is arranged on the connecting branch pipe.

3. The polysilicon production bleed gas recycling system according to claim 2, characterized in that: The buffer tank group includes a first buffer tank, a second buffer tank, a second connecting pipe, a third connecting pipe, a fourth connecting pipe, a second valve, a third valve, a fourth valve and a fifth valve. The second connecting pipe is respectively connected to the feed port of the first buffer tank and the feed port of the second buffer tank, the third connecting pipe is respectively connected to the discharge port of the first buffer tank and the feed port of the first feed tank, and the fourth connecting pipe is respectively connected to the discharge port of the second buffer tank and the feed port of the second feed tank; the second valve and the third valve are both arranged on the second connecting pipe, the second valve is used to control the material entering the first buffer tank, and the third valve is used to control the material entering the second buffer tank; the fourth valve is arranged on the third connecting pipe, and the fifth valve is arranged on the fourth connecting pipe.

4. The polysilicon production bleed gas recycling system according to claim 3, characterized in that: A first connecting pipe is provided on the connecting pipe between the first valve and the first feed tank, and a second connecting pipe is provided on the connecting pipe between the regulating valve group and the second feed tank; a first pressure relief filter is provided at the other end of the first connecting pipe, and a second pressure relief filter is provided at the other end of the second connecting pipe; a sixth valve is provided on the first connecting pipe, and a seventh valve is provided on the second connecting pipe.

5. The polysilicon production bleed gas recycling system according to claim 4, characterized in that: A fifth communicating pipe is connected between the first pressure relief filter and the second pressure relief filter. The fifth communicating pipe is provided with at least two second regulating valves for controlling the relief pressure of the first pressure relief filter and the second pressure relief filter respectively.

6. The polysilicon production bleed gas recycling system according to claim 5, characterized in that: The first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve and the seventh valve are all cut-off valves.

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