Automatic hydrogen supplement control method and system of polycrystalline silicon production system

Abstract

The invention discloses an automatic hydrogen supplement control system and method of a polycrystalline silicon hydrogen production system, and belongs to the technical field of polycrystalline silicon production. The system comprises a pure hydrogen storage tank connected into a hydrogen production system, and a first hydrogen supplementing valve is arranged on a pipeline where the pure hydrogen storage tank is connected with a compressor front buffer tank. A second hydrogen supplementing valve is arranged on a pipeline for connecting the pure hydrogen storage tank and the hydrogen buffer tank, the first hydrogen supplementing valve, the second hydrogen supplementing valve and pressure detection devices on the compressor front buffer tank, the pure hydrogen storage tank and the hydrogen buffer tank are all connected into a control device, and the control device receives pressure signals fed back by the pressure detection devices; and the opening degrees of the first hydrogen supplementing valve and the second hydrogen supplementing valve are controlled according to a preset control logic to supplement hydrogen. By arranging the automatic hydrogen supplementing control system, automatic operation hydrogen supplementing based on pressure detection is achieved, the problems of excessive operation and frequent operation of operators are reduced, and the stability of the operation pressure of a production system is improved.

Description

Technical Field

[0001] The present invention relates to the field of polysilicon production, and in particular to an automatic hydrogen replenishment control method and system for a polysilicon production system. Background Art

[0002] In the polysilicon production process, hydrogen raw materials need to be added to the production system, and the amount of hydrogen input needs to be adjusted according to the internal pressure of the production system. At present, in the actual production process, the hydrogen replenishment operation of the production system mainly relies on the main control operator to manually operate the hydrogen replenishment valve to control the hydrogen input flow and input pressure. The manual hydrogen replenishment method has a large operating load for personnel, and manual operation based on experience alone cannot guarantee the stable operating pressure of the production system. If the system pressure is not stable, the following conditions will occur: ① If the system is not replenished with hydrogen in time or is insufficient, the pressure in front of the compressor in the hydrogen recovery system will be low, the compressor current will be low, and the operating stability of the equipment will be reduced.

[0003] ② The absorption effect of the tail gas steel structure system in the hydrogen recovery system is inversely proportional to the temperature and directly proportional to the pressure. If the system is not replenished with hydrogen in time or is insufficient, the low pressure of the tail gas steel structure system will reduce the absorption effect, and chlorosilane will not be able to effectively absorb the hydrogen chloride in the hydrogen, resulting in hydrogen with hydrogen chloride impurities entering the adsorption system, increasing the adsorption operation load.

[0004] ③ If the system replenishes too much hydrogen, it will cause the pressure in front of the compressor to be too high, the suction pressure of the compressor to be high, the return flow regulating valves before and after the machine to be fully closed, the pressure difference before and after the regulating valve to increase, and the on-site pipeline to vibrate greatly, causing safety hazards.

[0005] ④ If the system replenishes too much hydrogen, the pressure of the low-pressure system in front of the machine will be high, and the pressure difference between the tail gas pressure of the reduction process and the pressure in front of the machine will be reduced, resulting in poor release of the tail gas in the reduction process, affecting the production operation of the system.

[0006] It can be seen that manual hydrogen replenishment is difficult to ensure the stability of the operating pressure of the production system. At the same time, since the pressure of the pure hydrogen storage tank that provides hydrogen replenishment also fluctuates, the difficulty of manual hydrogen replenishment is increased, and the risk of system instability is further increased. In view of this, the present application proposes an automatic hydrogen replenishment control method and system for a polysilicon production system. Summary of the invention

[0007] The present invention aims to solve the problem that manual hydrogen replenishment in the production system in the prior art easily causes unstable system operating pressure, leading to a series of production problems. An automatic hydrogen replenishment control method and system for a polysilicon production system are proposed, which improves the stability of system operation by automatically controlling the amount of hydrogen replenishment entering the production system.

[0008] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows: An automatic hydrogen replenishment control method for a polysilicon production system, comprising: Obtain real-time pressure of pure hydrogen storage tank, pressure of hydrogen buffer tank in the rear high-pressure system, and pressure of buffer tank in front of compressor in the front low-pressure system; When the pressure difference between the pure hydrogen storage tank that provides hydrogen and the pressure of the hydrogen buffer tank in the rear high-pressure system meets the hydrogen replenishment condition, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, open the second hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the hydrogen buffer tank to replenish hydrogen to the hydrogen buffer tank; When the pressure difference between the pure hydrogen storage tank that provides hydrogen and the pressure of the hydrogen buffer tank in the rear high-pressure system does not meet the hydrogen replenishment conditions, and at the same time the pressure of the buffer tank in front of the compressor in the front low-pressure system indicates that the compressor is not operating at full load, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, open the first hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank in front of the compressor to replenish hydrogen to the buffer tank in front of the compressor.

[0009] Furthermore, during the hydrogen replenishment process, a pressure detection device is used to detect the target buffer tank pressure at a set frequency f. When the detected pressure does not reach the set pressure stabilization area, the hydrogen replenishment valve automatically increases the set opening until it is detected that the pressure value of the target buffer tank is in the set pressure stabilization area, and then the hydrogen replenishment valve is closed.

[0010] Furthermore, when the pressure of the pure hydrogen storage tank is lower than a set lower limit, hydrogen replenishment is prohibited, and the first hydrogen replenishment valve and the second hydrogen replenishment valve are controlled to be closed.

[0011] Furthermore, when the pressure of the buffer tank before the compressor is higher than the tail gas pressure of the reduction process, the first hydrogen replenishing valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank before the compressor is closed.

[0012] The present invention also proposes an automatic hydrogen replenishment control system for a polysilicon production system, including a pure hydrogen storage tank connected to the hydrogen production system, wherein the pure hydrogen storage tank is respectively connected to a compressor front buffer tank in a front low-pressure system and a hydrogen buffer tank in a rear high-pressure system; a first hydrogen replenishment valve for controlling the on-off of the circuit is arranged on a pipeline connecting the pure hydrogen storage tank and the compressor front buffer tank, and a second hydrogen replenishment valve for controlling the on-off of the circuit is arranged on a pipeline connecting the pure hydrogen storage tank and the hydrogen buffer tank; pressure detection devices are arranged on the compressor front buffer tank, the pure hydrogen storage tank and the hydrogen buffer tank, and the first hydrogen replenishment valve, the second hydrogen replenishment valve and each pressure detection device are connected to a control device, and the control device receives a pressure signal fed back from each pressure detection device, and controls the opening of the first hydrogen replenishment valve and the second hydrogen replenishment valve according to a preset control logic to replenish hydrogen.

[0013] Furthermore, when the pressure difference between the pure hydrogen storage tank pressure fed back by the pressure detection device and the hydrogen buffer tank pressure meets the hydrogen replenishment condition, and at the same time the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, the control device outputs a control signal to control the second hydrogen replenishment valve to open, so as to replenish hydrogen to the hydrogen buffer tank.

[0014] Furthermore, when the pressure difference between the pure hydrogen storage tank pressure fed back by the pressure detection device and the pressure of the hydrogen buffer tank in the rear high-pressure system does not meet the hydrogen replenishment conditions, and the pressure of the buffer tank in front of the compressor in the front low-pressure system indicates that the compressor is not in full load operation, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, the control device outputs a control signal to control the first hydrogen replenishment valve to open and replenish hydrogen to the buffer tank in front of the compressor.

[0015] Furthermore, the control device receives the target buffer tank pressure detected in real time by the pressure detection device at a set frequency during the process of controlling the opening of the hydrogen filling valve and replenishing hydrogen, and when the detected pressure value does not reach the set pressure stabilization area, controls the hydrogen filling valve to automatically increase the set opening until it detects that the pressure value of the target buffer tank is in the set pressure stabilization area, and then closes the hydrogen filling valve.

[0016] Furthermore, when the pressure detection device detects that the pressure of the pure hydrogen storage tank itself is lower than a set lower limit, the control device controls the first hydrogen replenishing valve and the second hydrogen replenishing valve to close.

[0017] Furthermore, when the control device detects that the pressure of the buffer tank before the compressor is higher than the tail gas pressure of the reduction process, it closes the first hydrogen replenishing valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank before the compressor.

[0018] In summary, the present invention has the following advantages: 1. The present invention detects the pressure of the pure hydrogen storage tank, the buffer tank before the compressor in the low-pressure system before the machine, and the hydrogen buffer tank in the low-pressure system after the machine in real time, and automatically operates the hydrogen replenishment in combination with the preset automatic control logic, thereby reducing the problem of excessive and frequent operations by operators and improving the stability of the system operating pressure; 2. The present invention can realize full-process automatic control of hydrogen replenishment, automatically adjust the opening of the hydrogen replenishment valve according to the system pressure, and ensure the stability of the system pressure; 3. The hydrogen replenishment control system of the present invention makes hydrogen replenishment control more precise, the system pressure more stable, and reduces system venting waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the hydrogen replenishment system of the present invention; In the figure: 1. Compressor, 2. Buffer tank before compressor, 3. Buffer tank after compressor, 4. Steel structure system, 5. Adsorption system, 6. Hydrogen buffer tank, 7. Pure hydrogen storage tank, 8. First hydrogen replenishing valve, 9. Second hydrogen replenishing valve. DETAILED DESCRIPTION

[0020] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments and drawings. It should be understood by those skilled in the art that the content described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0021] Example 1 This embodiment provides an automatic hydrogen replenishment control system for a polysilicon production system, and the automatic hydrogen replenishment control system is connected to a hydrogen recovery system in the production system. Figure 1 As shown, the hydrogen recovery system includes a low-pressure system in front of the machine, a compressor, and a high-pressure system in the rear of the machine, which are connected in sequence. The low-pressure system in front of the machine includes a buffer tank in front of the compressor, and the inlet of the buffer tank in front of the compressor is connected to the reduction tail gas delivery pipeline. The high-pressure system in the rear of the machine includes a buffer tank in the rear of the compressor, a tail gas recovery steel structure system, a hydrogen adsorption system, and a hydrogen buffer tank, which are connected in sequence.

[0022] After the reduction tail gas is initially condensed, it enters the buffer tank before the machine to stabilize the pressure and then is pressurized in the compressor. It then enters the steel structure system absorption tower from the buffer tank after the compressor for absorption. After absorption, it enters the adsorption system to obtain qualified hydrogen, and then enters the hydrogen buffer tank to stabilize the pressure before entering the reduction furnace again as a raw material. When the system pressure is too high, the hydrogen buffer tank can be emptied to keep the system pressure stable.

[0023] The buffer tank after the compressor is connected to the buffer tank before the compressor through a connecting pipe, and a compressor reflux regulating valve is provided on the connecting pipe. When the reflux regulating valve is opened, the hydrogen at the high-pressure end after the compressor refluxes to the low-pressure end in front of the compressor to stabilize the pressure of the buffer tank in front of the compressor, and also ensure the stable operation of the compressor to avoid low pressure in front of the compressor, abnormal current during low-load operation, etc.

[0024] The automatic hydrogen replenishment control system of the present invention comprises a pure hydrogen storage tank, a first hydrogen replenishment valve, a second hydrogen replenishment valve and a control device. The pure hydrogen storage tank is connected to the production system and is connected to the compressor front buffer tank in the front low-pressure system and the hydrogen buffer tank in the rear high-pressure system. The first hydrogen replenishment valve is arranged on the pipeline connecting the pure hydrogen storage tank and the compressor front buffer tank to control the on-off of the pipeline, and the second hydrogen replenishment valve is arranged on the pipeline connecting the pure hydrogen storage tank and the hydrogen buffer tank to control the on-off of the pipeline.

[0025] Pressure detection devices are provided on the buffer tank in front of the compressor, the pure hydrogen storage tank and the hydrogen buffer tank. The first hydrogen replenishing valve, the second hydrogen replenishing valve and each pressure detection device are connected to the control device. The control device receives the pressure signal fed back from each pressure detection device, and controls the opening of the first hydrogen replenishing valve and the second hydrogen replenishing valve according to the preset control logic to replenish hydrogen, thereby ensuring the stable pressure of the production system.

[0026] Specifically, the preset control logic of the control device includes: When the pressure difference between the pure hydrogen storage tank pressure fed back by the pressure detection device and the hydrogen buffer tank pressure meets the hydrogen replenishment condition, and at the same time the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, the control device outputs a control signal to control the second hydrogen replenishment valve to open, replenishing hydrogen to the hydrogen buffer tank; When the pressure difference between the pure hydrogen storage tank pressure fed back by the pressure detection device and the pressure of the hydrogen buffer tank in the rear high-pressure system does not meet the hydrogen replenishment conditions, and at the same time the pressure of the buffer tank in front of the compressor in the front low-pressure system indicates that the compressor is not operating at full load, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, the control device outputs a control signal to control the first hydrogen replenishment valve to open, and replenish hydrogen to the buffer tank in front of the compressor.

[0027] Furthermore, when controlling the opening of the hydrogen replenishing valve and replenishing hydrogen, the control device receives the target buffer tank pressure detected in real time by the pressure detection device at a set frequency, and when the detected pressure value does not reach the set pressure stabilization area, the control device controls the hydrogen replenishing valve to automatically increase the set opening until it detects that the pressure value of the target buffer tank is in the set pressure stabilization area, and then closes the hydrogen replenishing valve.

[0028] Furthermore, when the pressure detection device detects that the pressure of the pure hydrogen storage tank itself is lower than the set lower limit, the control device controls the first hydrogen replenishing valve and the second hydrogen replenishing valve to close.

[0029] Furthermore, when the control device detects that the pressure of the buffer tank before the compressor is higher than the exhaust gas pressure of the reduction process, it closes the first hydrogen replenishing valve on the connecting pipeline between the pure hydrogen storage tank and the buffer tank before the compressor to prevent the low-pressure system before the machine from having high pressure, and the exhaust gas pressure of the reduction process and the pressure difference before the machine from being reduced, resulting in poor exhaust gas release in the reduction process and affecting the production operation of the system.

[0030] The automatic hydrogen replenishment control system of the present invention can automatically adjust the opening of the hydrogen replenishment valve according to the real-time feedback signal of the pressure detection device to realize automatic operation of hydrogen replenishment, reduce the problem of excessive and frequent operations by operators, and ensure the stability of system pressure.

[0031] At the same time, the automatic hydrogen replenishment control system monitors the pressure of the low-pressure system in front of the machine, the pressure of the high-pressure system behind the machine, and the pressure of the pure hydrogen storage tank itself, and combines the corresponding control logic to achieve rapid response of pressure regulation. The control is more precise and can quickly maintain the stability of the operating pressure of the production system.

[0032] Example 2 This embodiment provides an automatic hydrogen replenishment control method for a polysilicon production system, comprising the following steps: Obtain real-time pressure of pure hydrogen storage tank, pressure of hydrogen buffer tank in the rear high-pressure system, and pressure of buffer tank in front of compressor in the front low-pressure system; When the pressure difference between the pure hydrogen storage tank that provides hydrogen and the pressure of the hydrogen buffer tank in the rear high-pressure system meets the hydrogen replenishment condition, and at the same time the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, open the second hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the hydrogen buffer tank to replenish hydrogen to the hydrogen buffer tank; When the pressure difference between the pure hydrogen storage tank that provides hydrogen and the pressure of the hydrogen buffer tank in the rear high-pressure system does not meet the hydrogen replenishment conditions, and at the same time the pressure of the buffer tank in front of the compressor in the front low-pressure system indicates that the compressor is not operating at full load, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, open the first hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank in front of the compressor to replenish hydrogen to the buffer tank in front of the compressor.

[0033] Preferably, during the process of hydrogen replenishment before or after the engine, the pressure detection device detects the target buffer tank pressure at a set frequency f. When the detected pressure does not reach the set pressure stabilization area, the hydrogen replenishment valve automatically increases the set opening until it detects that the pressure value of the target buffer tank is in the set pressure stabilization area, and then closes the hydrogen replenishment valve.

[0034] Preferably, when the pressure of the pure hydrogen storage tank itself is lower than a set lower limit, hydrogen replenishment is prohibited, and the first hydrogen replenishment valve and the second hydrogen replenishment valve are closed.

[0035] Preferably, when the pressure of the buffer tank before the compressor is higher than the tail gas pressure of the reduction process, the first hydrogen replenishment valve is closed to prevent the low-pressure system pressure before the machine from being high, and the pressure difference between the tail gas pressure of the reduction process and the pressure before the machine from being reduced, resulting in poor release of the tail gas from the reduction process, affecting the production operation of the system.

[0036] The automatic hydrogen replenishment control method is explained below through specific control parameters.

[0037] According to the system control parameter requirements: the control pressure before the compressor is 0.47~0.52MPa; the control pressure after the compressor is 0.85~0.98MPa; the control pressure of the hydrogen buffer tank is 0.835~0.865MPa.

[0038] ① When the pressure difference between the pure hydrogen storage tank pressure and the hydrogen buffer tank pressure is ≥50kpa, and the hydrogen buffer tank pressure is <0.835MPa, the control device controls the second hydrogen replenishment valve to open and replenish hydrogen (after the hydrogen replenishment valve is actuated, the hydrogen buffer tank pressure is detected every 30 seconds. If it does not reach 0.865MPa, the valve automatically increases the opening by 10%); when the hydrogen buffer tank pressure is >0.865MPa, the hydrogen replenishment regulating valve hydrogen replenishment valve 2 is closed; ② When the pressure difference between the pure hydrogen storage tank and the hydrogen buffer tank is less than 50kpa and the pressure of the pressure buffer tank in front of the compressor is less than 0.47MPa, the pressure of the hydrogen buffer tank is less than 0.835MPa, and the first hydrogen replenishing valve of the pressure buffer tank in front of the compressor is opened to replenish hydrogen to the low-pressure system in front of the machine (the hydrogen replenishing valve is operated and the pressure of the hydrogen buffer tank is tested every 30 seconds. When it does not reach 0.865MPa, the valve automatically increases the opening by 10%). When the pressure of the hydrogen buffer tank is greater than 0.865MPa, the first hydrogen replenishing valve is closed.

[0039] Protection settings: When the pure hydrogen storage tank pressure is less than 0.7MPa, it is prohibited to open the first hydrogen replenishment valve or the second hydrogen replenishment valve; When the pressure of the buffer tank before the compressor is greater than 0.475MPa, close the first hydrogen replenishment valve.

[0040] Through the above control strategy, the control method of the present invention can quickly respond to system pressure regulation, and the regulation is more precise, and can quickly maintain the stability of the operating pressure of the production system.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An automatic hydrogen replenishment control method for a polysilicon production system, characterized in that: include: Obtain real-time pressure of pure hydrogen storage tank, pressure of hydrogen buffer tank in the rear high-pressure system, and pressure of buffer tank in front of compressor in the front low-pressure system; When the pressure difference between the pure hydrogen storage tank that provides hydrogen and the pressure of the hydrogen buffer tank in the rear high-pressure system meets the hydrogen replenishment condition, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, open the second hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the hydrogen buffer tank to replenish hydrogen to the hydrogen buffer tank; When the pressure difference between the pure hydrogen storage tank that provides hydrogen and the pressure of the hydrogen buffer tank in the rear high-pressure system does not meet the hydrogen replenishment conditions, and at the same time the pressure of the buffer tank in front of the compressor in the front low-pressure system indicates that the compressor is not operating at full load, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, open the first hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank in front of the compressor to replenish hydrogen to the buffer tank in front of the compressor.

2. The automatic hydrogen replenishment control method for a polysilicon production system according to claim 1, characterized in that: During the hydrogen replenishment process, a pressure detection device is used to detect the target buffer tank pressure at a set frequency f. When the detected pressure does not reach the set pressure stabilization area, the hydrogen replenishment valve automatically increases the set opening until it detects that the pressure value of the target buffer tank is in the set pressure stabilization area, and then closes the hydrogen replenishment valve.

3. The automatic hydrogen replenishment control method for a polysilicon production system according to claim 1, characterized in that: When the pressure of the pure hydrogen storage tank itself is lower than the set lower limit, hydrogen replenishment is prohibited, and the first hydrogen replenishment valve and the second hydrogen replenishment valve are closed.

4. The automatic hydrogen replenishment control method for a polysilicon production system according to claim 1, characterized in that: When the pressure of the buffer tank before the compressor is higher than the tail gas pressure of the reduction process, close the first hydrogen replenishment valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank before the compressor.

5. An automatic hydrogen replenishment control system for a polysilicon production system, comprising a pure hydrogen storage tank connected to a hydrogen production system, characterized in that: The pure hydrogen storage tank is respectively connected to the compressor front buffer tank in the front low-pressure system and the hydrogen buffer tank in the rear high-pressure system; a first hydrogen replenishment valve for controlling the on-off of the line is arranged on the pipeline connecting the pure hydrogen storage tank and the compressor front buffer tank, and a second hydrogen replenishment valve for controlling the on-off of the line is arranged on the pipeline connecting the pure hydrogen storage tank and the hydrogen buffer tank; pressure detection devices are arranged on the compressor front buffer tank, the pure hydrogen storage tank and the hydrogen buffer tank, and the first hydrogen replenishment valve, the second hydrogen replenishment valve and each pressure detection device are connected to the control device, and the control device receives the pressure signal fed back from each pressure detection device, and automatically controls the opening of the first hydrogen replenishment valve and the second hydrogen replenishment valve according to the preset control logic to replenish hydrogen.

6. The automatic hydrogen replenishment control system of a polysilicon production system according to claim 1, characterized in that: When the pressure difference between the pure hydrogen storage tank pressure fed back by the pressure detection device and the hydrogen buffer tank pressure meets the hydrogen replenishment condition, and at the same time the pressure of the hydrogen buffer tank is less than the set pressure stabilization area, the control device outputs a control signal to control the second hydrogen replenishment valve to open, so as to replenish hydrogen to the hydrogen buffer tank.

7. The automatic hydrogen replenishment control system of a polysilicon production system according to claim 1, characterized in that: The control device outputs a control signal to control the first hydrogen replenishment valve to open and replenish hydrogen to the buffer tank in front of the compressor when the pressure difference between the pure hydrogen storage tank pressure fed back by the pressure detection device and the pressure of the hydrogen buffer tank in the rear high-pressure system does not meet the hydrogen replenishment conditions, and the pressure of the buffer tank in front of the compressor in the front low-pressure system indicates that the compressor is not in a full-load operation state, and the pressure of the hydrogen buffer tank is less than the set pressure stabilization area.

8. The automatic hydrogen replenishment control system of a polysilicon production system according to claim 1, characterized in that: The control device receives the target buffer tank pressure detected in real time by the pressure detection device at a set frequency during the process of controlling the opening of the hydrogen replenishing valve and replenishing hydrogen, and controls the hydrogen replenishing valve to automatically increase the set opening when the detected pressure value does not reach the set pressure stabilization area, and closes the hydrogen replenishing valve after detecting that the pressure value of the target buffer tank is in the set pressure stabilization area.

9. The automatic hydrogen replenishment control system of a polysilicon production system according to claim 1, characterized in that: The control device controls the first hydrogen replenishing valve and the second hydrogen replenishing valve to close when the pressure detection device detects that the pressure of the pure hydrogen storage tank itself is lower than the set lower limit.

10. The automatic hydrogen replenishment control system of a polysilicon production system according to claim 1, characterized in that: When the control device detects that the pressure of the buffer tank before the compressor is higher than the tail gas pressure of the reduction process, the control device closes the first hydrogen replenishing valve on the pipeline connecting the pure hydrogen storage tank and the buffer tank before the compressor.

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