Method for treating exhaust gas of a polysilicon coating plant and exhaust gas piping system

Abstract

The application provides a polysilicon coating equipment tail gas treatment method and a tail gas pipeline system. The polysilicon coating equipment tail gas treatment method comprises the following steps: step S10, tail gas purging, inert gas is used to purge the furnace cavity of a reaction furnace and the tail gas pipeline system; step S20, first-time introduction of oxygen-containing combustion-supporting gas into the tail gas pipeline system, so that the residual tail gas in the tail gas pipeline system reacts with the oxygen-containing combustion-supporting gas to cause primary combustion; and step S30, second-time introduction of oxygen-containing combustion-supporting gas into the tail gas pipeline system, so that the residual tail gas in the tail gas pipeline system reacts with the oxygen-containing combustion-supporting gas to cause secondary combustion, wherein the first gas flow rate of the first-time introduction of the oxygen-containing combustion-supporting gas is less than the second gas flow rate of the second-time introduction of the oxygen-containing combustion-supporting gas, and the ratio of the second gas flow rate to the first gas flow rate is 1.38-827.5. The polysilicon coating equipment tail gas treatment method provided by the application ensures the safety of the polysilicon coating equipment tail gas treatment process and avoids the occurrence of pipe explosion events.

Description

Technical Field

[0001] This application relates to the field of exhaust gas treatment technology in solar cell manufacturing, and in particular to exhaust gas treatment methods and exhaust gas pipeline systems for polycrystalline silicon coating equipment. Background Technology

[0002] In the fabrication of tunnel oxide passivated contact (Topcon) solar cells, a doped polycrystalline silicon layer is typically fabricated on the tunnel oxide layer using coating equipment. This polycrystalline silicon coating equipment usually includes a reactor with a tail gas outlet and a tail gas piping system connected to the reactor's tail gas outlet. During the fabrication of the polycrystalline silicon layer, process gases such as silane, phosphine, and hydrogen are used. During the process, silicon nitride and silicon oxide powdery solids are generated and adhere to the inner wall of the tail gas piping of the coating equipment. After a certain period, tail gas pipe blockage occurs, requiring disassembly and cleaning of each tail gas pipe. Furthermore, residual silane and hydrogen remain in the tail gas pipes. When the tail gas pipes are disassembled, these two gases can spontaneously combust or even explode upon contact with air, posing a significant threat to production safety. Summary of the Invention

[0003] The first aspect of this application provides a method for treating the exhaust gas of a polycrystalline silicon coating equipment. The polycrystalline silicon coating equipment includes a reactor and an exhaust gas pipeline system connected to the exhaust gas outlet of the reactor. The method for treating the exhaust gas of the polycrystalline silicon coating equipment includes: Step S10, exhaust gas purging, using inert gas to purge the furnace cavity and exhaust gas pipeline system of the reactor; Step S20: Introduce oxygen-containing combustion-supporting gas into the exhaust gas pipeline system for the first time, so that the residual exhaust gas in the exhaust gas pipeline system reacts with the oxygen-containing combustion-supporting gas to produce initial combustion. Step S30: A second oxygen-containing combustion-supporting gas is introduced into the exhaust gas pipeline system to allow the residual exhaust gas in the system to react with the oxygen-containing combustion-supporting gas and undergo a second combustion. The first intake flow rate of the oxygen-containing combustion-supporting gas introduced for the first time is less than the second intake flow rate of the oxygen-containing combustion-supporting gas introduced for the second time. The ratio of the second intake flow rate to the first intake flow rate is 1.38 ~ 827.5 (the ratio is calculated here based on the intake flow rates of the needle valve and the intake valve).

[0004] In some optional embodiments of the first aspect of this application, In step S20, Oxygen-containing combustion-supporting gas is first introduced into the exhaust gas pipeline system through a pinhole valve installed on the system. In step S30, the intake of gas through the needle valve is stopped and replaced by the intake valve installed on the exhaust gas pipeline system to introduce oxygen-containing combustion gas for the second time.

[0005] In some optional embodiments of the first aspect of this application, the intake valve is a manual intake valve.

[0006] In some optional embodiments of the first aspect of this application, the first intake flow rate through the needle valve ranges from 0.4 ml / min to 71 ml / min, and the second intake flow rate through the intake valve ranges from 98 ml / min to 331 ml / min.

[0007] In some optional embodiments of the first aspect of this application, the ratio of the first gas volume introduced during the first introduction of oxygen-containing combustion-supporting gas to the second gas volume introduced during the second introduction of oxygen-containing combustion-supporting gas is 0.288 to 7.68.

[0008] In some optional embodiments of the first aspect of this application, In step S20, the first duration of introducing oxygen-containing combustion-supporting gas into the exhaust gas pipeline system by opening the needle valve is 10 min to 30 min.

[0009] In some optional embodiments of the first aspect of this application, Step S30 includes: Repeat the opening and closing operation of the intake valve 20 to 50 times, performing the operation once every 10 to 30 seconds. During each opening and closing of the intake valve: the intake valve is opened for 0.5s to 1s, and the total opening degree of the intake valve is gradually increased to 1 / 3 to 3 / 4.

[0010] In some optional embodiments of the first aspect of this application, The system includes: a tail gas discharge pipe, a silane discharge pipe, a tail gas treatment pipe, and a gas supply bypass pipe. The tail gas discharge pipe is connected to the tail gas outlet of the reactor, and a vacuum pump is installed on the tail gas discharge pipe. A bypass pipe for inputting oxygen-containing combustion-supporting gas is connected to the exhaust pipe. An intake valve and a pinhole valve are sequentially installed on the bypass pipe along the direction of oxygen-containing combustion-supporting gas input. The pinhole valve is detachably installed on the bypass pipe. In steps other than S20, a reserved valve blind plate is used to replace the pinhole valve. The bypass pipe is located before the intake end of the vacuum pump. A three-way valve is installed after the outlet of the vacuum pump. The inlet of the three-way valve is connected to the exhaust pipe, the first outlet of the three-way valve is connected to the silane exhaust pipe, and the second outlet of the three-way valve is connected to the exhaust treatment pipe.

[0011] In some optional embodiments of the first aspect of this application, the exhaust gas treatment pipe is connected to an exhaust gas treatment device.

[0012] In some optional embodiments of the first aspect of this application, in steps S20 and S30, the air inlet of the three-way valve is connected to the second air outlet of the three-way valve, and the vacuum pump is in working condition.

[0013] In some optional embodiments of the first aspect of this application, the exhaust gas treatment pipe includes a power end pipe and a tail end pipe. The first end of the power end pipe is connected to the second outlet of a three-way valve, and the second end of the power end pipe is detachably connected to the inlet of the tail end pipe via a pipe connector. The exhaust gas treatment method for polycrystalline silicon coating equipment further includes: Step S40: Connect the first end of the power end pipe to the reserved port of the exhaust gas treatment equipment, clean the inside of the power end pipe, and pass the dust and residual exhaust gas inside the power end pipe into the exhaust gas treatment equipment for treatment.

[0014] In some optional embodiments of the first aspect of this application, it further includes: Step S50: Disassemble the exhaust gas pipeline system to obtain multiple pipes and a three-way valve, and clean the inside of each pipe, including the power end pipe and the tail end pipe.

[0015] In some optional embodiments of the first aspect of this application, the power end pipe has the longest length among the plurality of pipes.

[0016] In some optional embodiments of the first aspect of this application, step S10 includes: The three-way valve is controlled to cycle between the first and second air outlets 10 to 50 times, with each cycle lasting a total of 20 to 120 seconds. In each cycle, the air outlet at the first outlet lasts for 10 to 60 seconds, and the air outlet at the second outlet lasts for 10 to 60 seconds. In some optional embodiments of the first aspect of this application, the flow rate of the inert gas is 1 × 10⁻⁶. 4 ml / min ~ 5×10 5 ml / min.

[0017] In some optional embodiments of the first aspect of this application, the inert gas is nitrogen.

[0018] A second aspect of this application provides a tail gas pipeline system for a polycrystalline silicon coating equipment. The tail gas pipeline system includes: a tail gas discharge pipe, a silane discharge pipe, a tail gas treatment pipe, and a bypass pipe. The tail gas discharge pipe is connected to the process tail gas outlet of the reactor of the polycrystalline silicon coating equipment, and a vacuum pump is installed on the tail gas discharge pipe. A bypass pipe for inputting oxygen-containing combustion-supporting gas is connected to the exhaust pipe. An intake valve and a pinhole valve are sequentially installed on the bypass pipe along the direction of oxygen-containing combustion-supporting gas input. The pinhole valve is detachably installed on the bypass pipe and can be replaced with a reserved valve blind plate after being removed from the bypass pipe. The bypass pipe is located before the intake end of the vacuum pump. The needle valve is used to introduce oxygen-containing flame-retardant gas into the exhaust gas pipeline system for the first time, and the intake valve is used to introduce oxygen-containing flame-retardant gas into the exhaust gas pipeline system for the second time.

[0019] The second aspect of this application provides a needle valve with a diameter of 1 mm to 10 mm.

[0020] In some optional embodiments of the second aspect of this application, the intake valve is a manual intake valve with a nominal diameter of DN25.

[0021] Beneficial effects: The exhaust gas treatment method for polycrystalline silicon coating equipment provided in the first aspect of this application involves two combustion processes. First, a small-flow-rate oxygen-containing combustion-supporting gas is introduced to slowly react and burn the exhaust gas to be treated (e.g., silane and hydrogen), consuming the exhaust gas and preventing open flames and deflagration accidents. Then, a larger-flow-rate oxygen-containing combustion-supporting gas is introduced to rapidly burn the remaining small amount of exhaust gas, preventing open flames or even explosions that could occur during subsequent maintenance and cleaning of the exhaust gas pipeline system. This ensures the safety of the polycrystalline silicon coating equipment exhaust gas treatment process and avoids pipe rupture incidents.

[0022] The exhaust gas pipeline system of the polycrystalline silicon coating equipment provided in the second aspect of this application is equipped with a detachable pinhole valve and an inlet valve on the gas supply bypass pipe. By adjusting the different valves, the flow rate of the oxygen-containing combustion-supporting gas supplied to the exhaust gas pipeline system of the polycrystalline silicon coating equipment before the pipeline is disassembled is adjusted. First, the gas is introduced through the pinhole valve for slow reaction and combustion, and then a large flow of oxygen-containing combustion-resistant gas is introduced through the inlet valve to enable rapid and complete combustion of the residual silane and hydrogen in the exhaust gas pipeline system. This facilitates the removal of residual silane and hydrogen in the pipeline before disassembling and cleaning the exhaust gas pipeline system of the polycrystalline silicon coating equipment, prevents pipeline rupture incidents, ensures the life, health and safety of the personnel maintaining the polycrystalline silicon coating equipment, and improves production safety. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the exhaust gas pipeline system of the polycrystalline silicon coating equipment in the embodiments of this application.

[0024] Explanation of reference numerals in the attached figures: Furnace cavity -01; Furnace exhaust outlet -011; Exhaust gas piping system-1; Intake valve-11; Needle valve-12; Exhaust gas discharge pipe-13; Silane pipe-14; Exhaust gas treatment pipe-15; Power end pipe-151; Tail end pipe-152; Gas supply bypass pipe-16; Vacuum pump-17; Three-way valve -18; Three-way valve inlet -181; Three-way valve first outlet -182; Three-way valve second outlet -183; Exhaust gas treatment device-2. Detailed Implementation

[0025] The following will be combined with the appendix Figure 1 The technical solution of this application is described in detail.

[0026] The first aspect of this application provides a method for treating the exhaust gas of a polycrystalline silicon coating equipment. The polycrystalline silicon coating equipment includes a reactor and an exhaust gas pipeline system 1 connected to the exhaust gas outlet 011 of the reactor. The method for treating the exhaust gas of the polycrystalline silicon coating equipment includes: Step S10, exhaust gas purging, using inert gas to purge the furnace chamber 01 and exhaust gas pipeline system 1 of the reactor; Step S20: First, oxygen-containing combustion-supporting gas is introduced into the exhaust gas pipeline system 1 so that the residual exhaust gas in the exhaust gas pipeline system 1 reacts with the oxygen-containing combustion-supporting gas to produce initial combustion. Step S30: A second oxygen-containing combustion-supporting gas is introduced into the exhaust gas pipeline system 1, so that the residual exhaust gas in the exhaust gas pipeline system 1 reacts with the oxygen-containing combustion-supporting gas to undergo a second combustion. The first intake flow rate of the oxygen-containing combustion-supporting gas is less than the second intake flow rate of the oxygen-containing combustion-supporting gas. The ratio of the second intake flow rate to the first intake flow rate is 1.38 to 827.5.

[0027] In these embodiments, the purpose of step S10 is to allow residual silane and hydrogen in the furnace chamber 01 of the reactor to be discharged from the furnace chamber and the tail gas pipeline system 1 by inert gas after each poly coating preparation. The tail gas treatment method for polycrystalline silicon coating equipment provided in the first aspect of this application involves two combustion processes. First, a small-flow-rate oxygen-containing combustion-supporting gas is introduced to slowly react and burn the tail gas to be treated (e.g., silane and hydrogen), consuming the tail gas and preventing open flames and deflagration accidents. Then, a larger-flow-rate oxygen-containing combustion-supporting gas is introduced to allow the remaining small amount of tail gas to burn quickly and completely, avoiding the occurrence of open flames or even deflagration accidents during subsequent maintenance and cleaning of the tail gas pipeline system 1. This ensures the safety of the tail gas treatment process for polycrystalline silicon coating equipment and avoids pipe rupture incidents.

[0028] Polycrystalline silicon deposition equipment can also be called a tubular plasma polycrystalline silicon deposition furnace. Several key process gases are used in the deposition of polycrystalline silicon (Poly-Si) thin films in this equipment: silane (SiH4), which is the main silicon source gas for polycrystalline silicon deposition. At high temperatures, silane decomposes to generate silicon atoms, which are then deposited on the silicon wafer surface to form a polycrystalline silicon thin film; phosphine (PH3), used to achieve in-situ doping of the polycrystalline silicon film; and hydrogen (H2), which mainly acts as a carrier gas and diluent in the process, helping to uniformly deliver the reactive gases such as silane and phosphine into the reaction chamber, while diluting the gas concentration to avoid defects caused by localized over-concentration.

[0029] In some optional embodiments of the first aspect of this application, In step S20, Oxygen-containing combustion-supporting gas is first introduced into the exhaust gas pipeline system 1 through the pinhole valve 12 installed on the exhaust gas pipeline system 1. In step S30, the intake of gas through the needle valve 12 is stopped and the oxygen-containing combustion gas is introduced for the second time through the intake valve 11 installed on the exhaust gas pipeline system 1.

[0030] In these embodiments, the oxygen-containing combustion-supporting gas is air.

[0031] In these embodiments, the intake diameter of the pinhole valve 12 is in the millimeter range, much smaller than that of a conventional intake valve 11 (in some examples, the nominal diameter of the intake valve 11 is DN25). During the first combustion process, the residual exhaust gas concentration in the exhaust gas pipeline system 1 is relatively high, and introducing a large flow of gas may lead to dangerous problems such as combustion explosion and pipe rupture. Introducing gas through the pinhole valve 12 allows the residual exhaust gas adhering to the pipe wall, which is not easily carried away by the inert gas, to react slowly with the oxygen-containing flame-retardant gas during the first introduction, resulting in a lower degree of combustion. This process not only removes residual exhaust gas (including silane and hydrogen) but also prevents pipe rupture, thus improving the safety of the exhaust gas pipeline system 1.

[0032] In some optional embodiments of the first aspect of this application, the intake valve 11 is a manual intake valve 11.

[0033] In some optional embodiments of the first aspect of this application, the air intake flow rate of the needle valve 12 is in the range of 0.4 ml / min to 71 ml / min, and the air intake flow rate of the air intake valve 11 is in the range of 98 ml / min to 331 ml / min.

[0034] In some optional embodiments of this application, the air inlet of the intake valve 11 is larger than the air inlet of the needle valve 12, and the ratio of the first gas volume introduced when oxygen-containing combustion-supporting gas is introduced for the first time to the second gas volume introduced when oxygen-containing combustion-supporting gas is introduced for the second time is 0.288 to 7.68. The first gas volume refers to the total intake volume entering through the needle valve 12, and the second gas volume refers to the total intake volume entering through the intake valve 11.

[0035] In some optional embodiments of the first aspect of this application, In step S20, the first duration of introducing oxygen-containing combustion-supporting gas into the exhaust gas pipeline system 1 by opening the needle valve 12 is 10 min to 30 min.

[0036] In some optional embodiments of the first aspect of this application, Step S30 includes: Repeat the opening and closing operation of intake valve 11 20 to 50 times, performing the opening and closing operation of intake valve 11 once every 10 to 30 seconds. During each operation of opening and closing the intake valve 11: the intake valve 11 is opened for 0.5s to 1s, and the total opening degree of the intake valve 11 is gradually increased to 1 / 3 to 3 / 4.

[0037] In these embodiments, in step S30, since exhaust gas is introduced into the exhaust gas pipeline system 1 through the intake valve 11, the single intake volume is large. In order to ensure combustion safety in the exhaust gas pipeline system 1, the operator needs to manually open and close the manual intake valve 11 repeatedly for intermittent intake.

[0038] In other examples, the intake valve 11 can also be repeatedly opened and closed by an electric actuator.

[0039] In some optional embodiments of the first aspect of this application, The system includes: a tail gas discharge pipe 13, a silane discharge pipe 14, a tail gas treatment pipe 15, and a gas supply bypass pipe 16. The tail gas discharge pipe 13 is connected to the tail gas outlet 011 of the reactor, and a vacuum pump 17 is installed on the tail gas discharge pipe 13. A bypass pipe 16 for inputting oxygen-containing combustion-supporting gas is connected to the exhaust pipe 13. An intake valve 11 and a pinhole valve 12 are sequentially arranged on the bypass pipe 16 along the input direction of the oxygen-containing combustion-supporting gas. The pinhole valve 12 is detachably mounted on the bypass pipe 16. In steps other than S20, a reserved valve blind plate is used to replace the pinhole valve 12. The bypass pipe 16 is located before the intake end of the vacuum pump 17. A three-way valve 18 is installed after the outlet of the vacuum pump 17. The inlet 181 of the three-way valve is connected to the exhaust pipe 13, the first outlet 182 of the three-way valve is connected to the silane pipe 14, and the second outlet 183 of the three-way valve is connected to the exhaust treatment pipe 15.

[0040] In these embodiments, a reserved valve blind plate is installed at the position corresponding to the subsequent needle valve 12 in step S10. Before proceeding to step S20, the reserved valve blind plate is removed and then the needle valve 12 is installed. After completing step S20, the needle valve 12 is removed and then the reserved valve blind plate is reinstalled.

[0041] In some optional embodiments of the first aspect of this application, the exhaust gas treatment pipe 15 is connected to an exhaust gas treatment device 2 at its outlet. In these embodiments, the exhaust gas treatment device 2 can treat silane, hydrogen, etc., remaining in the pipe.

[0042] In some optional embodiments of the first aspect of this application, in steps S20 and S30, the air inlet 181 of the three-way valve is connected to the second air outlet 183 of the three-way valve, and the vacuum pump 17 is in working condition.

[0043] In some optional embodiments of the first aspect of this application, the exhaust gas treatment pipe 15 includes a power end pipe 151 and a tail end pipe 152. The first end of the power end pipe 151 is connected to the second outlet 183 of the three-way valve, and the second end of the power end pipe 151 is detachably connected to the tail end pipe 152 via a pipe connector. The exhaust gas treatment method for polycrystalline silicon coating equipment further includes: Step S40: Connect the first end of the power end pipe 151 to the reserved port of the exhaust gas treatment equipment, clean the inside of the power end pipe 151, and pass the dust and residual exhaust gas inside the power end pipe 151 into the exhaust gas treatment equipment for treatment.

[0044] In some optional embodiments of the first aspect of this application, it further includes: Step S50: Disassemble the exhaust gas pipeline system 1 to obtain multiple pipes and a three-way valve 18, and clean the inside of each pipe. The multiple pipes include the power end pipe 151 and the tail end pipe 152.

[0045] In some optional embodiments of the first aspect of this application, the power end pipe 151 has the longest length among the plurality of pipes.

[0046] In some optional embodiments of the first aspect of this application, the plurality of pipes include a power end pipe 151, a tail end pipe 152, an exhaust pipe 13 and a silane pipe 14, that is, the three-way valve 18 and each pipe in the exhaust pipe system 1 are disassembled and cleaned.

[0047] In some examples of these embodiments, the power-end pipe 151 is located in the workshop mezzanine and is the longest pipe in the entire exhaust gas treatment pipe system of 15 pipes. After completing step S30, to prevent trace amounts of silane and hydrogen from remaining in the power-end pipe 151, which would pose a significant risk of spontaneous combustion and deflagration during subsequent pipe disassembly and cleaning, the longest power-end pipe 151 is reconnected to the exhaust gas treatment equipment for exhaust gas discharge treatment before all pipes in the exhaust gas pipe system 1 are disassembled. The exhaust gas treatment equipment may be equipped with a suction device to ensure that the exhaust gas is smoothly drawn out and treated from the power-end pipe 151.

[0048] In some embodiments, the first end of the power end pipe 151 is connected to a reserved port of the exhaust gas treatment equipment via a specially designed long corrugated pipe. The corresponding power end pipe 151 is cleaned in the workshop interlayer, and then the dust and residual exhaust gas in the power end pipe 151 are safely treated by the exhaust gas treatment equipment. The exhaust gas treatment equipment can be a new exhaust gas treatment device 2 or an existing one. This step can fully combust the residual silane and hydrogen in the power pipe, preventing pipe rupture. Water can be used to remove dust and form a slurry, which is then better discharged into the exhaust gas treatment device 2.

[0049] In some optional embodiments of the first aspect of this application, step S10 includes: The three-way valve 18 is controlled to cycle between the first and second air outlets 10 to 50 times, with each cycle lasting a total of 20 to 120 seconds. In each cycle, the air outlet at the first outlet lasts for 10 to 60 seconds, and the air outlet at the second outlet lasts for 10 to 60 seconds.

[0050] In these embodiments, the switching of the three-way valve 18 enables the use of inert gas to drive away the silane and hydrogen remaining in the furnace chamber 01, silane exhaust pipe 14, and power end pipe 151 of the reactor. In order for the exhaust gas treatment device 2 to fully combust the silane and hydrogen residue in the power pipe and prevent pipe rupture, the silane exhaust pipe is connected to the inlet of a dedicated silane exhaust treatment system and is discharged after meeting the emission standards.

[0051] In some optional embodiments of the first aspect of this application, the flow rate of the inert gas is 1 × 10⁻⁶. 4 ml / min ~ 5×10 5 ml / min.

[0052] In some optional embodiments of the first aspect of this application, the inert gas is nitrogen.

[0053] A second aspect of this application provides a tail gas pipeline system 1 for a polycrystalline silicon coating equipment. The tail gas pipeline system 1 includes: a tail gas discharge pipe 13, a silane discharge pipe 14, a tail gas treatment pipe 15, and a gas supply bypass pipe 16. The tail gas discharge pipe 13 is connected to the process tail gas outlet of the reactor of the polycrystalline silicon coating equipment, and a vacuum pump 17 is installed on the tail gas discharge pipe 13. A bypass pipe 16 for inputting oxygen-containing combustion-supporting gas is connected to the exhaust pipe 13. An intake valve 11 and a pinhole valve 12 are sequentially arranged on the bypass pipe 16 along the input direction of the oxygen-containing combustion-supporting gas. The pinhole valve 12 is detachably mounted on the bypass pipe 16. After the pinhole valve 12 is removed from the bypass pipe 16, it is replaced by a reserved valve blind plate. The bypass pipe 16 is located before the intake end of the vacuum pump 17. The needle valve 12 is used to introduce oxygen-containing flame-retardant gas into the exhaust gas pipeline system 1 for the first time, and the intake valve 11 is used to introduce oxygen-containing flame-retardant gas into the exhaust gas pipeline system 1 for the second time.

[0054] The second aspect of this application provides that the diameter of the needle valve 12 is 1 mm to 10 mm.

[0055] In some optional embodiments of the second aspect of this application, the intake valve 11 is a manual intake valve 11, and the nominal diameter of the manual intake valve 11 is DN25.

[0056] The exhaust gas pipeline system 1 of the polycrystalline silicon coating equipment provided in the second aspect of this application is equipped with a detachable pinhole valve 12 and an intake valve 11 on the gas supply bypass pipe 16. By adjusting the intake flow rate of the oxygen-containing combustion-supporting gas supplied to the exhaust gas pipeline system 1 of the polycrystalline silicon coating equipment before the pipeline is disassembled, the gas is first introduced through the pinhole valve 12 for slow reaction and combustion, and then a large flow of oxygen-containing combustion-retardant gas is introduced through the intake valve 11 to enable the rapid and complete combustion of the residual silane and hydrogen in the exhaust gas pipeline system 1. This facilitates the removal of residual silane and hydrogen in the pipeline before disassembling and cleaning the exhaust gas pipeline system 1 of the polycrystalline silicon coating equipment, prevents pipeline bursting incidents, and ensures the life, health and safety of the personnel maintaining the polycrystalline silicon coating equipment.

[0057]

Example 1

[0058] The exhaust gas treatment methods for polycrystalline silicon coating equipment include: Step S10: Tail gas purging. Nitrogen gas is used to purge the furnace chamber 01 and tail gas pipeline system 1 of the reactor. The three-way valve 18 is controlled to cycle between the first and second outlets 10 to 50 times, with each cycle lasting 20 to 120 seconds. The outlet time in each cycle is 10 to 60 seconds, and the outlet time in each cycle is also 10 to 60 seconds. The inert gas flow rate is 1 × 10⁻⁶. 4 ml / min ~ 5×10 5 ml / min.

[0059] In step S20, air is introduced into the exhaust gas pipeline system 1 for the first time through the pinhole valve 12 installed on the exhaust gas pipeline system 1 so that the residual exhaust gas in the exhaust gas pipeline system 1 reacts with the air to produce initial combustion. The first duration of the oxygen-containing combustion-supporting gas introduced into the exhaust gas pipeline system 1 through the pinhole valve 12 for the first time is 10 min to 30 min. The air inlet 181 of the three-way valve is connected to the second air outlet 183 of the three-way valve.

[0060] Step S30: Stop the air intake through the needle valve 12 and switch to the manual air intake valve 11 installed on the exhaust gas pipeline system 1 to allow the residual exhaust gas in the exhaust gas pipeline system 1 to react with the air and undergo a second combustion. Repeat the opening and closing operation of the air intake valve 11 20 to 50 times, and perform the opening and closing operation of the air intake valve 11 once every 10 to 30 seconds. In each opening and closing operation of the air intake valve 11: the opening time of the air intake valve 11 is 0.5 to 1 second, and the total opening degree of the air intake valve 11 is gradually opened to 1 / 3 to 3 / 4. The air inlet 181 of the three-way valve is connected to the second air outlet 183 of the three-way valve.

[0061] Step S40: Connect the first end of the power end pipe 151 to the reserved port of the exhaust gas treatment equipment, clean the inside of the power end pipe 151, and pass the dust and residual exhaust gas inside the power end pipe 151 into the exhaust gas treatment equipment for treatment.

[0062] Step S50: Disassemble the exhaust gas pipeline system 1 to obtain multiple pipes and a three-way valve 18, and clean the inside of each pipe. The multiple pipes include the power end pipe 151 and the tail end pipe 152.

[0063] In some examples, step S40 stops vacuum pump 17 from operating in step S50.

[0064] In some specific examples, in step S20, the air intake time is 10 min, the air intake volume is 4.71 ml, and the air intake flow rate is 0.47 ml / min; in step S30, the air intake time is 10 s, the air intake volume is 16 ml, the air intake flow rate is 98 ml / min, and the ratio of the air intake volume of the needle valve 12 to the manual air intake valve 11 is 0.288.

[0065] In other specific examples, in step S20, the air intake time is 30 minutes, the air intake volume is 2119.5 ml, and the air flow rate is 70.65 ml / min; in step S30, the air intake time is 50 seconds, the air intake volume is 276 ml, and the air flow rate is 331 ml / min, with the air intake volume ratio of the pinhole valve 12 to the manual air intake valve 11 being 768. Tests have shown that using the parameters in these two specific examples for exhaust gas treatment of the polycrystalline silicon coating equipment did not produce any open flames or explosions.

[0066] The exhaust gas treatment method of the polycrystalline silicon coating equipment in this application embodiment can effectively ensure the thorough removal of residual silane and hydrogen in the exhaust gas pipeline system 1 of the polycrystalline silicon coating equipment, and prevent safety accidents such as open flames or even deflagration.

[0067] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for treating exhaust gas from a polycrystalline silicon coating equipment, characterized in that, The polycrystalline silicon coating equipment includes a reactor and a tail gas pipeline system connected to the tail gas outlet of the reactor. The tail gas treatment method of the polycrystalline silicon coating equipment includes: Step S10, exhaust gas purging, using inert gas to purge the furnace cavity and the exhaust gas pipeline system of the reactor; Step S20: First, oxygen-containing combustion-supporting gas is introduced into the exhaust gas pipeline system so that the residual exhaust gas in the exhaust gas pipeline system reacts with the oxygen-containing combustion-supporting gas to undergo initial combustion. Step S30: A second oxygen-containing combustion-supporting gas is introduced into the exhaust gas pipeline system so that the residual exhaust gas in the exhaust gas pipeline system reacts with the oxygen-containing combustion-supporting gas to undergo a second combustion. Wherein, the first intake flow rate of the oxygen-containing combustion-supporting gas introduced for the first time is less than the second intake flow rate of the oxygen-containing combustion-supporting gas introduced for the second time, and the ratio of the second intake flow rate to the first intake flow rate is 1.38 ~ 827.

5.

2. The exhaust gas treatment method of the polycrystalline silicon coating equipment according to claim 1, characterized in that, In step S20 Oxygen-containing combustion-supporting gas is first introduced into the exhaust gas pipeline system through a pinhole valve installed on the system. In step S30, the intake of gas through the pinhole valve is stopped and the oxygen-containing combustion gas is introduced for the second time through the intake valve installed on the exhaust gas pipeline system. Preferably, the intake valve is a manual intake valve; Preferably, the first air intake flow rate through the needle valve is in the range of 0.4 ml / min to 71 ml / min, and the second air intake flow rate through the air intake valve is in the range of 98 ml / min to 331 ml / min. The ratio of the first gas volume introduced during the first introduction of oxygen-containing combustion-supporting gas to the second gas volume introduced during the second introduction of oxygen-containing combustion-supporting gas is 0.288 to 7.

68.

3. The exhaust gas treatment method for polycrystalline silicon coating equipment according to claim 2, characterized in that, In step S20, the duration for which oxygen-containing combustion-supporting gas is first introduced into the exhaust gas pipeline system by opening the pinhole valve is 10 min to 30 min.

4. The exhaust gas treatment method of the polycrystalline silicon coating equipment according to claim 2, characterized in that, Step S30 includes: Repeat the opening and closing operation of the intake valve 20 to 50 times, performing the opening and closing operation once every 10 to 30 seconds. During each operation of opening and closing the intake valve: the intake valve is opened for 0.5s to 1s, and the total opening degree of the intake valve is gradually increased to 1 / 3 to 3 / 4.

5. The exhaust gas treatment method for polycrystalline silicon coating equipment according to claim 2, characterized in that, The exhaust gas piping system includes: an exhaust gas discharge pipe, a silane discharge pipe, an exhaust gas treatment pipe, and a bypass pipe. The exhaust gas discharge pipe is connected to the exhaust gas outlet of the reactor, and a vacuum pump is installed on the exhaust gas discharge pipe. The exhaust pipe is connected to a bypass pipe for inputting the oxygen-containing combustion-supporting gas. An intake valve and a pinhole valve are sequentially arranged on the bypass pipe along the direction of the oxygen-containing combustion-supporting gas input. The pinhole valve is detachably mounted on the bypass pipe. In steps other than S20, a pre-reserved valve blind plate replaces the pinhole valve. The bypass pipe is located before the intake end of the vacuum pump. A three-way valve is installed after the outlet of the vacuum pump. The inlet of the three-way valve is connected to the exhaust pipe, the first outlet of the three-way valve is connected to the silane exhaust pipe, and the second outlet of the three-way valve is connected to the exhaust treatment pipe. Preferably, the exhaust gas treatment pipe is connected to an exhaust gas treatment device at its outlet end; Preferably, in steps S20 and S30, the air inlet of the three-way valve is connected to the second air outlet of the three-way valve, and the vacuum pump is in operation.

6. The exhaust gas treatment method for the polycrystalline silicon coating equipment according to claim 5, characterized in that, The exhaust gas treatment pipe includes a power end pipe and a tail end pipe. The first end of the power end pipe is connected to the second outlet of the three-way valve. The second end of the power end pipe is detachably connected to the inlet end of the tail end pipe through a pipe connector. The outlet end of the tail end pipe is connected to the exhaust gas treatment device. The exhaust gas treatment method of the polycrystalline silicon coating equipment further includes: Step S40: Connect the first end of the power end pipe to the reserved port of the exhaust gas treatment equipment, clean the inside of the power end pipe, and pass the dust and residual exhaust gas inside the power end pipe into the exhaust gas treatment equipment for treatment.

7. The exhaust gas treatment method for the polycrystalline silicon coating equipment according to claim 6, characterized in that, Further includes: Step S50: Disassemble the exhaust gas pipeline system to obtain multiple pipes and a three-way valve, and clean the inside of each pipe. The multiple pipes include the power end pipe and the tail end pipe. Preferably, the power end pipe has the longest length among the plurality of pipes.

8. The exhaust gas treatment method for a polycrystalline silicon coating equipment according to any one of claims 4 to 8, characterized in that, Step S10 includes: The three-way valve is controlled to cycle between the first air outlet and the second air outlet 10 to 50 times, with each cycle lasting a total of 20 to 120 seconds. In each cycle, the air outlet at the first air outlet lasts for 10 to 60 seconds, and the air outlet at the second air outlet lasts for 10 to 60 seconds. Preferably, the flow rate of the inert gas is 1×10⁻⁶. 4 ml / min ~ 5×10 5 ml / min; Preferably, the inert gas is nitrogen.

9. A tail gas pipeline system for a polycrystalline silicon coating equipment, characterized in that, The exhaust gas piping system includes: an exhaust gas discharge pipe, a silane discharge pipe, an exhaust gas treatment pipe, and a bypass pipe. The exhaust gas discharge pipe is connected to the process exhaust gas outlet of the reactor in the polycrystalline silicon coating equipment, and a vacuum pump is installed on the exhaust gas discharge pipe. The exhaust pipe is connected to a bypass pipe for inputting oxygen-containing combustion-supporting gas. An intake valve and a pinhole valve are sequentially arranged on the bypass pipe along the direction of oxygen-containing combustion-supporting gas input. The pinhole valve is detachably mounted on the bypass pipe and can be replaced with a pre-installed blind flange after being removed from the bypass pipe. The bypass pipe is located before the intake end of the vacuum pump. The pinhole valve is used to introduce oxygen-containing flame-retardant gas into the exhaust gas pipeline system for the first time, and the intake valve is used to introduce oxygen-containing flame-retardant gas into the exhaust gas pipeline system for the second time.

10. The exhaust gas piping system of the poly device according to claim 9, characterized in that, The diameter of the needle valve is 1 mm to 10 mm.

Images