Polycrystalline silicon reduction tail gas heat energy recycling system

Abstract

The utility model discloses a polycrystalline silicon reduction tail gas heat energy recycling system, which relates to the technical field of polycrystalline silicon production reduction process, and is characterized in that a trichlorosilane tail gas heat exchanger and a hydrogen tail gas heat exchanger are additionally arranged on a reduction tail gas main pipe, and the reduction tail gas is divided into two parts; one part enters the trichlorosilane tail gas heat exchanger to exchange heat with trichlorosilane tail gas, and the other part enters the hydrogen tail gas heat exchanger to exchange heat with hydrogen. The temperature of the reduction tail gas is reduced, and the temperatures of trichlorosilane and hydrogen are increased. And the reduced reduction tail gas enters the tail gas recovery system, so that the temperature difference required by circulating water cooling of the recovered tail gas is reduced, and the cooling demand of the tail gas recovery system is effectively reduced. And the trichlorosilane and the hydrogen after temperature rise enter a subsequent system for steam heating, and then enter the polycrystalline silicon reduction furnace, so that the temperature difference required by reduction inlet steam heating is reduced, and the steam consumption is effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical fields of polysilicon production reduction process and heat energy recovery and utilization, and more specifically to a polysilicon reduction tail gas heat energy recovery and utilization system. Background Art

[0002] At present, the process of preparing polysilicon in the polysilicon production system is as follows: trichlorosilane and hydrogen are introduced into the reduction furnace, and polysilicon is deposited on the silicon core at 1100°C by reaction. The material that is not completely reacted in the polysilicon production process is called reduction tail gas, and the components of the reduction tail gas are mainly silicon powder, hydrogen, hydrogen chloride and chlorosilane, among which chlorosilane includes dichlorosilane, trichlorosilane and tetrachlorosilane. After the reduction tail gas comes out of the reduction furnace, it enters the tail gas recovery system.

[0003] The existing technology includes the following two solutions:

[0004] Existing technical solution 1:

[0005] ① Trichlorosilane (liquid) at about 40°C is transported from the recovery process to the reduction process. It is first heated to about 115°C (gas state) by vaporizer steam heating, then heated to about 135°C by superheater steam heating, and then transported to the reduction furnace; (40°C to 135°C, steam heating temperature difference 95°C).

[0006] ② Hydrogen at room temperature of about 25°C is transported from the recovery process to the reduction process and then to the reduction furnace.

[0007] ③ The gaseous trichlorosilane heated to about 135°C from the superheater and the hydrogen at about 25°C from the recovery section are mixed evenly in the reduction furnace mixer, and the temperature is reduced to about 80°C. The mixed gas is then heated by steam from the air inlet heater, and the mixed gas is heated to 140°C before being transported to the reduction furnace for reaction. (80°C to 140°C, the steam heating temperature difference is 60°C).

[0008] ④ The tail gas at about 160°C generated after the reduction reaction is directly transported to the recovery process and is cooled down through the recovery process.

[0009] In the above-mentioned prior art solution 1, steam is used for heating, which consumes a large amount of steam.

[0010] Existing technical solution 2:

[0011] ① Trichlorosilane (liquid) at about 40°C is transported from the recovery process to the reduction process. It is first heated to about 115°C (gas state) by vaporizer steam heating, then heated to about 135°C by superheater steam heating, and then transported to the reduction furnace; (40°C to 135°C, steam heating temperature difference 95°C).

[0012] ② Hydrogen at room temperature of about 25°C is transported from the recovery process to the reduction process and then to the reduction furnace.

[0013] ③ The gaseous trichlorosilane heated to about 135°C from the superheater and the hydrogen at about 25°C from the recovery section are mixed evenly in the reduction furnace mixer, and the temperature is reduced to about 80°C. Then, the mixed gas is heated by the intake heater and the tail gas of the reduction furnace, and the mixed gas is heated and transported to the reduction furnace for reaction (the tail gas temperature and gas volume change with the reaction time, and the temperature range of the mixed gas after heating varies greatly and cannot be accurately controlled). (80°C is heated to 80-140°C, and the tail gas heat exchange temperature difference is 0-60°C).

[0014] ④ The exhaust gas at about 160°C generated after the reduction reaction is reduced to 100-160°C after heat exchange with the intake air through the intake heater, and then transported to the recovery process for further temperature reduction and cooling. Utility Model Content

[0015] In order to overcome the defects existing in the above-mentioned prior art, the purpose of the utility model is to provide a polysilicon reduction tail gas heat energy recovery and utilization system. The utility model adds two sets of heat exchangers on the material main pipe (hydrogen, trichlorosilane, tail gas) entering and exiting the reduction device boundary area, and divides the reduction tail gas into two parts, one part is heat exchanged with the hydrogen entering the heat exchanger, and the other part is heat exchanged with the trichlorosilane entering the heat exchanger. The hydrogen, trichlorosilane and tail gas after heat exchange are transported according to the original process, and are equipped with corresponding regulating valves and detection instruments to adjust the gas volume distribution and realize automatic control.

[0016] In order to achieve the above objectives, the technical solution adopted by the utility model is:

[0017] A polysilicon reduction tail gas heat energy recovery and utilization system, comprising:

[0018] A reduction tail gas main pipe, wherein the inlet end of the reduction tail gas main pipe is connected to the polysilicon reduction furnace, and the outlet end of the reduction tail gas main pipe is connected to the tail gas recovery system;

[0019] A trichlorosilane tail gas heat exchanger and a hydrogen tail gas heat exchanger connected in parallel, wherein the inlet and outlet ends of the heat exchange and cooling flow channels of the trichlorosilane tail gas heat exchanger and the hydrogen tail gas heat exchanger are connected to the reduction tail gas main pipe through pipelines;

[0020] A trichlorosilane heating feed pipe and a trichlorosilane heating discharge pipe, wherein the inlet end of the trichlorosilane heating feed pipe is connected to the trichlorosilane recovery system, and the outlet end is connected to the inlet end of the heat exchange and heating flow channel of the trichlorosilane tail gas heat exchanger, and the inlet end of the trichlorosilane heating discharge pipe is connected to the outlet end of the heat exchange and heating flow channel of the trichlorosilane tail gas heat exchanger;

[0021] A hydrogen heating feed pipe and a hydrogen heating discharge pipe, wherein the inlet end of the hydrogen heating feed pipe is connected to the hydrogen recovery system, and the outlet end is connected to the inlet end of the heat exchange and heating channel of the hydrogen tail gas heat exchanger, and the inlet end of the hydrogen heating discharge pipe is connected to the outlet end of the heat exchange and heating channel of the hydrogen tail gas heat exchanger.

[0022] Preferably, the outlet end of the trichlorosilane heating discharge pipe is connected to a vaporizer, and the vaporizer is connected to a superheater.

[0023] Preferably, the hydrogen temperature-raising discharge pipe and the superheater are both connected to the reduction furnace mixer, the reduction furnace mixer is connected to the air intake heater, and the air intake heater is connected to the polysilicon reduction furnace.

[0024] Preferably, a first thermometer is installed on the trichlorosilane heating and discharging pipe, a first valve is installed on the pipeline connected to the inlet end of the heat exchange and cooling channel of the trichlorosilane tail gas heat exchanger, and the first valve is electrically connected to the first thermometer.

[0025] Preferably, the pipelines at the outlet ends of the heat exchange and cooling flow channels of the trichlorosilane tail gas heat exchanger and the hydrogen tail gas heat exchanger are connected to the outlet main pipe, and the outlet main pipe is further connected to the reduction tail gas main pipe, and a second thermometer is installed on the outlet main pipe; a first connecting pipe is arranged between the trichlorosilane heating feed pipe and the trichlorosilane heating discharge pipe, a second valve is installed on the first connecting pipe, and the second valve is electrically connected to the second thermometer.

[0026] Preferably, a flow meter is installed on the hydrogen heating feed pipe, and a third thermometer is installed on the hydrogen heating discharge pipe.

[0027] Preferably, a second connecting pipe is provided between the hydrogen heating feed pipe and the hydrogen heating discharge pipe, and a third valve is installed on the second connecting pipe.

[0028] Preferably, a safety valve is provided on the trichlorosilane heating discharge pipe.

[0029] Preferably, the safety valve is connected to the exhaust system via a pipeline.

[0030] Preferably, the vaporizer is connected to a steam pipeline network, and a steam regulating valve group is installed on the steam pipeline network.

[0031] Beneficial effects of the utility model:

[0032] The polysilicon reduction tail gas heat energy recovery and utilization system provided by the utility model adds a heat exchanger to exchange heat between the intake air (trichlorosilane and hydrogen) and the tail gas entering and leaving the boundary area, fully recovers and utilizes the waste heat carried by the tail gas, reduces the temperature difference required for reducing the intake steam heating, reduces the steam consumption for intake heating, and reduces the cooling capacity required for cooling the recovered tail gas.

[0033] The utility model provides a polysilicon reduction tail gas heat energy recovery and utilization system, in which a heat exchanger is arranged on the reduction tail gas main pipe, and is equipped with corresponding control valves and detection instruments. Its tail gas temperature and gas volume are more stable than those of a single reduction furnace. The control valve adjusts the distribution gas volume, and the tail gas temperature control fluctuation range delivered to the recovery is small, which is convenient for stable control of the recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the polysilicon reduction tail gas heat energy recovery and utilization system of the utility model;

[0035] Reference numerals:

[0036] 1. Reduction tail gas main pipe; 2. Trichlorosilane tail gas heat exchanger; 3. Hydrogen tail gas heat exchanger; 4. Trichlorosilane heating feed pipe; 5. Trichlorosilane heating discharge pipe; 6. Hydrogen heating feed pipe; 7. Hydrogen heating discharge pipe; 8. First thermometer; 9. First valve; 10. Second thermometer; 11. Second valve; 12. Flow meter; 13. Third thermometer; 14. Third valve; 15. Safety valve; 16. Vaporizer; 17. Steam pipe network; 18. Steam regulating valve group. DETAILED DESCRIPTION

[0037] The concept, specific structure and technical effects of the present invention will be clearly and completely described below in combination with the embodiments and drawings to fully understand the purpose, features and effects of the present invention.

[0038] A polysilicon reduction tail gas heat energy recovery and utilization system, such as Figure 1 As shown, including:

[0039] A reduction tail gas main pipe 1, wherein the inlet end of the reduction tail gas main pipe 1 is connected to the polysilicon reduction furnace, and the outlet end is connected to the tail gas recovery system;

[0040] The trichlorosilane tail gas heat exchanger 2 and the hydrogen tail gas heat exchanger 3 are connected in parallel, and the inlet and outlet ends of the heat exchange and cooling flow channels of the trichlorosilane tail gas heat exchanger 2 and the hydrogen tail gas heat exchanger 3 are connected to the reduction tail gas main pipe 1 through pipelines;

[0041] A trichlorosilane heating feed pipe 4 and a trichlorosilane heating discharge pipe 5, wherein the inlet end of the trichlorosilane heating feed pipe 4 is connected to the trichlorosilane recovery system, and the outlet end is connected to the inlet end of the heat exchange and heating flow channel of the trichlorosilane tail gas heat exchanger 2, and the inlet end of the trichlorosilane heating discharge pipe 5 is connected to the outlet end of the heat exchange and heating flow channel of the trichlorosilane tail gas heat exchanger 2;

[0042] A hydrogen heating feed pipe 6 and a hydrogen heating discharge pipe 7, wherein the inlet end of the hydrogen heating feed pipe 6 is connected to the hydrogen recovery system, and the outlet end is connected to the inlet end of the heat exchange and heating channel of the hydrogen tail gas heat exchanger 3, and the inlet end of the hydrogen heating discharge pipe 7 is connected to the outlet end of the heat exchange and heating channel of the hydrogen tail gas heat exchanger 3.

[0043] In this embodiment, a trichlorosilane tail gas heat exchanger 2 and a hydrogen tail gas heat exchanger 3 are added to the reduction tail gas main pipe 1, and the reduction tail gas is divided into two parts, one part enters the trichlorosilane tail gas heat exchanger 2 to exchange heat with the trichlorosilane tail, and the other part enters the hydrogen tail gas heat exchanger 3 to exchange heat with the hydrogen. In the trichlorosilane tail gas heat exchanger 2, the reduction tail gas and trichlorosilane are heat exchanged, the temperature of the reduction tail gas is reduced, and the temperature of the trichlorosilane is increased. In the hydrogen tail gas heat exchanger 3, the temperature of the reduction tail gas is reduced, and the temperature of the hydrogen is increased. The reduction tail gas after the temperature is reduced enters the tail gas recovery system again, reducing the temperature difference required for cooling the circulating water of the recovered tail gas, and effectively reducing the cooling demand of the tail gas recovery system. After the temperature is increased, the trichlorosilane and hydrogen enter the subsequent system for steam heating, and then enter the polysilicon reduction furnace, reducing the temperature difference required for heating the reduction intake steam, and effectively reducing the steam consumption.

[0044] In this embodiment, the outlet end of the trichlorosilane heating discharge pipe 5 is connected to a vaporizer 16, and the vaporizer 16 is connected to a superheater. The vaporizer 16 is used to heat and vaporize the trichlorosilane, and the superheater is used to further heat the vaporized trichlorosilane.

[0045] In this embodiment, the hydrogen heating discharge pipe 7 and the superheater are both connected to the reduction furnace mixer, the reduction furnace mixer is connected to the air intake heater, and the air intake heater is connected to the polysilicon reduction furnace. The reduction furnace mixer is used to mix the heated trichlorosilane and hydrogen, and the air intake heater is used to heat the mixed gas before transporting it to the polysilicon reduction furnace.

[0046] like Figure 1 As shown, a first thermometer 8 is installed on the trichlorosilane heating and discharging pipe 5 , and a first valve 9 is installed on the pipeline connected to the inlet end of the heat exchange and cooling flow channel of the trichlorosilane tail gas heat exchanger 2 . The first valve 9 is electrically connected to the first thermometer 8 .

[0047] In this embodiment, the first valve 9 and the first thermometer 8 are in a reaction control mode (the valve is closed when the temperature rises; conversely, the valve is opened when the temperature decreases). The first valve 9 plays a role in restoring the exhaust gas volume distribution. By changing the valve opening, the heat entering the trichlorosilane exhaust gas heat exchanger 2 is adjusted to achieve precise control of the temperature rise of trichlorosilane, effectively preventing the trichlorosilane temperature from being too high and causing vaporization overpressure.

[0048] like Figure 1As shown, the pipelines at the outlet ends of the heat exchange and cooling flow channels of the trichlorosilane tail gas heat exchanger 2 and the hydrogen tail gas heat exchanger 3 are connected to the outlet main pipe, and the outlet main pipe is further connected to the reduction tail gas main pipe 1, and a second thermometer 10 is installed on the outlet main pipe; a first connecting pipe is arranged between the trichlorosilane heating feed pipe 4 and the trichlorosilane heating discharge pipe 5, and a second valve 11 is installed on the first connecting pipe, and the second valve 11 is electrically connected to the second thermometer 10.

[0049] In this embodiment, the second valve 11 and the second thermometer 10 are in a reaction control mode (the valve is closed when the temperature rises; conversely, the valve is opened when the temperature decreases). The second valve 11 plays a role in distributing the flow of trichlorosilane entering the trichlorosilane tail gas heat exchanger 2. By changing the valve opening, the temperature of the second thermometer 10 of the tail gas outlet main pipe is accurately controlled to prevent liquefaction and condensation due to excessive flow of cold trichlorosilane and excessively low tail gas temperature.

[0050] like Figure 1 As shown, a flow meter 12 is installed on the hydrogen heating feed pipe 6, and a third thermometer 13 is installed on the hydrogen heating discharge pipe 7. The flow meter 12 is used to measure the amount of hydrogen entering the hydrogen tail gas heat exchanger 3, which is convenient for metering and process accounting. The third thermometer 13 is used to detect the hydrogen temperature of the hydrogen heating discharge pipe 7, and judge whether the required process conditions are met through temperature detection, so as to guide the relevant process adjustments.

[0051] like Figure 1 As shown, a second connecting pipe is provided between the hydrogen heating feed pipe 6 and the hydrogen heating discharge pipe 7, and a third valve 14 is installed on the second connecting pipe. The second connecting pipe is used to connect the hydrogen heating feed pipe and the discharge pipe. When the hydrogen tail gas heat exchanger 3 fails and needs to be repaired, it is connected as a bypass to cut the hydrogen tail gas heat exchanger 3 out of the process. The third valve 14 is used to connect the hydrogen heating feed pipe and the discharge pipe when the hydrogen tail gas heat exchanger 3 is cut out of the system (the third valve 14 is in a closed state during normal operation, and the valves on the feed pipe and the discharge pipe are in an open state. When the system is cut off, the third valve 14 is in an open state, and the valves on the feed pipe and the discharge pipe are in a closed state).

[0052] like Figure 1 As shown, a safety valve 15 is provided on the trichlorosilane heating discharge pipe 5, and the safety valve 15 is connected to the exhaust gas system through a pipeline.

[0053] In this embodiment, a safety valve 15 is provided on the trichlorosilane heating discharge pipe 5. When the system operates abnormally and the temperature of trichlorosilane is too high, vaporization overpressure may occur, causing overpressure damage to the equipment / pipeline. The safety valve 15 sets a set pressure according to the design value of the pipeline / equipment. When the pressure in the pipeline exceeds the set pressure of the safety valve 15, it automatically trips and releases the pressure to the exhaust system to protect the equipment and pipeline. After the pressure is released to a value lower than the return value of the safety valve 15, the safety valve 15 automatically closes and the system resumes normal operation.

[0054] like Figure 1 As shown, the vaporizer 16 is connected to a steam pipe network 17 , and a steam regulating valve group 18 is installed on the steam pipe network 17 .

[0055] In this embodiment, the steam pipe network 17 provides heating steam for the vaporizer 16, and the steam flow is controlled by the steam regulating valve group 18 to realize automatic and precise control of the temperature and pressure of the vaporizer 16 (the regulating valve is electrically connected to the vaporizer pressure gauge, and the valve is closed when the pressure increases, and the valve is opened when the pressure decreases). The vaporizer 16 is heated by steam to further heat the trichlorosilane heated by the trichlorosilane tail gas heat exchanger 2 to above the boiling point, and becomes gaseous trichlorosilane.

[0056] In order to better understand the present invention, the following is a complete description of the working principle of the present invention:

[0057] ① Trichlorosilane (liquid) at about 40°C is transported from the trichlorosilane recovery system to the reduction process, first transported to the trichlorosilane tail gas heat exchanger 2 through the trichlorosilane heating feed pipe 4, and the trichlorosilane is heated to about 80°C, and then transported to the vaporizer 16 through the trichlorosilane heating discharge pipe 5. The vaporizer 16 heats the trichlorosilane with steam to about 115°C (gaseous state), and then heated to about 135°C by steam heating in the superheater, and then transported to the reduction furnace; (80°C to 135°C, the steam heating temperature difference is 55°C).

[0058] ② Hydrogen at room temperature of about 25°C is transported from the hydrogen recovery system to the reduction process, first transported to the hydrogen tail gas heat exchanger 3 through the hydrogen heating feed pipe 6, the hydrogen is heated to 140°C, and then transported to the reduction furnace through the hydrogen heating discharge pipe 7.

[0059] ③ The gaseous trichlorosilane heated to about 135°C from the superheater and the hydrogen heated to about 140°C from the hydrogen heating discharge pipe 7 are mixed evenly in the reduction furnace mixer, and the temperature is reduced to about 137.5°C. The mixed gas is then heated by steam from the air inlet heater, and the mixed gas is heated to 140°C before being transported to the reduction furnace for reaction. (137.5°C to 140°C, the steam heating temperature difference is 2.5°C).

[0060] ④ The tail gas at about 160°C generated after the reduction reaction is cooled to about 90°C after heat exchange with hydrogen and trichlorosilane through the reduction tail gas main pipe 1, trichlorosilane tail gas heat exchanger 2 and hydrogen tail gas heat exchanger 3, and then transported to the tail gas recovery system for further temperature reduction and cooling through the recovery process.

[0061] Through the above process flow, the temperature of trichlorosilane and hydrogen entering the boundary area of ​​the reduction device is increased, and the temperature of the tail gas sent out of the boundary area is reduced, which reduces the temperature difference required for heating the reduction inlet steam, effectively reduces steam consumption; reduces the temperature difference required for cooling the recycled tail gas circulating water, and effectively reduces the system cooling demand. At the same time, the heat exchanger is set on the main pipe, equipped with corresponding control valves and detection instruments to achieve accurate and stable temperature control.

[0062] The implementation methods of the present invention are described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalents or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A polysilicon reduction tail gas heat energy recovery and utilization system, characterized in that: include: A reduction tail gas main pipe (1), wherein the inlet end of the reduction tail gas main pipe (1) is connected to the polysilicon reduction furnace, and the outlet end is connected to the tail gas recovery system; A trichlorosilane tail gas heat exchanger (2) and a hydrogen tail gas heat exchanger (3) connected in parallel with each other, wherein the inlet and outlet ends of the heat exchange and cooling flow channels of the trichlorosilane tail gas heat exchanger (2) and the hydrogen tail gas heat exchanger (3) are connected to the reduction tail gas main pipe (1) through pipelines; A trichlorosilane heating feed pipe (4) and a trichlorosilane heating discharge pipe (5), wherein the inlet end of the trichlorosilane heating feed pipe (4) is connected to the trichlorosilane recovery system, and the outlet end is connected to the inlet end of the heat exchange heating channel of the trichlorosilane tail gas heat exchanger (2), and the inlet end of the trichlorosilane heating discharge pipe (5) is connected to the outlet end of the heat exchange heating channel of the trichlorosilane tail gas heat exchanger (2); A hydrogen heating feed pipe (6) and a hydrogen heating discharge pipe (7), wherein the inlet end of the hydrogen heating feed pipe (6) is connected to the hydrogen recovery system, and the outlet end is connected to the inlet end of the heat exchange and heating channel of the hydrogen tail gas heat exchanger (3), and the inlet end of the hydrogen heating discharge pipe (7) is connected to the outlet end of the heat exchange and heating channel of the hydrogen tail gas heat exchanger (3).

2. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 1, characterized in that: The outlet end of the trichlorosilane heating discharge pipe (5) is connected to a vaporizer (16), and the vaporizer (16) is connected to a superheater.

3. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 2, characterized in that: The hydrogen temperature-raising discharge pipe (7) and the superheater are both connected to the reduction furnace mixer, the reduction furnace mixer is connected to the air intake heater, and the air intake heater is connected to the polysilicon reduction furnace.

4. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 1, characterized in that: A first thermometer (8) is installed on the trichlorosilane heating and discharging pipe (5), and a first valve (9) is installed on the pipeline connected to the inlet end of the heat exchange and cooling flow channel of the trichlorosilane tail gas heat exchanger (2), and the first valve (9) is electrically connected to the first thermometer (8).

5. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 1, characterized in that: The pipelines at the outlet ends of the heat exchange and cooling flow channels of the trichlorosilane tail gas heat exchanger (2) and the hydrogen tail gas heat exchanger (3) are connected to an outlet main pipe, and the outlet main pipe is further connected to the reduction tail gas main pipe (1), and a second thermometer (10) is installed on the outlet main pipe; a first connecting pipe is provided between the trichlorosilane heating feed pipe (4) and the trichlorosilane heating discharge pipe (5), and a second valve (11) is installed on the first connecting pipe, and the second valve (11) is electrically connected to the second thermometer (10).

6. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 1, characterized in that: The hydrogen temperature-raising feed pipe (6) is provided with a flow meter (12), and the hydrogen temperature-raising discharge pipe (7) is provided with a third thermometer (13).

7. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 6, characterized in that: A second connecting pipe is provided between the hydrogen heating feed pipe (6) and the hydrogen heating discharge pipe (7), and a third valve (14) is installed on the second connecting pipe.

8. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 1, characterized in that: The trichlorosilane temperature-increasing discharge pipe (5) is provided with a safety valve (15).

9. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 8, characterized in that: The safety valve (15) is connected to the exhaust system via a pipeline.

10. The polysilicon reduction tail gas heat energy recovery and utilization system according to claim 2, characterized in that: The vaporizer (16) is connected to a steam pipe network (17), and a steam regulating valve group (18) is installed on the steam pipe network (17).

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