A full-automatic intelligent control system and control method for a polysilicon reduction furnace

Abstract

The application discloses a kind of full-automatic intelligent control system and control method of polycrystalline silicon reduction furnace, belong to polycrystalline silicon reduction furnace control field, control system includes the control device that is cooperated with reduction furnace, control device includes control panel and with control panel electric connection voltage detection module, tail gas temperature detection module, logic processing module and execution module;Control method includes that reduction furnace automatic control process is divided into several stages according to reaction time, the control strategy of each stage can be individually set or adjusted;Voltage automatic control, tail gas temperature automatic control and tail gas temperature highest limit control are implemented for each stage.The application can improve the automation control rate of reduction furnace, ensure polycrystalline silicon reduction furnace production running stability and the replicability, reproducibility of index data.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polycrystalline silicon reduction furnace control, in particular to a polycrystalline silicon reduction furnace full-automatic intelligent system and a control method. BACKGROUND

[0002] In the process of producing polycrystalline silicon by Siemens method, the temperature of the silicon core in the whole operation cycle of the reduction furnace is mainly controlled by the current, and the power supply mode is mainly constant current variable voltage control. At present, with the increasing maturity of polycrystalline silicon production technology, the current process parameters are basically stable, forming a stable curve. During operation, when the composition of the feedstock into the reduction furnace changes, the ratio of the feedstock will change, which will affect the reaction in the reduction furnace and the change of the gas field temperature, resulting in the change of the resistance value of the silicon rod. When the resistance value of the silicon rod changes, the voltage fluctuation will be reflected first, that is, deviating from the original curve. In order to ensure the deposition rate of silicon on the surface of the silicon core and thus improve the yield of polycrystalline silicon per furnace, it is very important to discover and finely control the change of the ratio of H2 and TCS (trichlorosilane) into the reduction furnace in the first time.

[0003] At present, the material ratio is generally adjusted manually, and whether the situation in the reduction furnace is appropriate is observed manually. This method cannot discover the change of the composition of the material in the reduction furnace, and the DCS operator cannot discover the growth in the reduction furnace in time, but can only rely on the on-site inspection personnel to observe whether the ratio in the reduction furnace is appropriate. Therefore, there is currently a lack of monitoring means for the growth in the reduction furnace and a more reasonable control method.

[0004] In order to solve the above problems, the Chinese invention patent with the publication number CN112624121B and the publication date of September 28, 2021 and the name of a polycrystalline silicon production control system and a control method is disclosed in the prior art, which discloses the following technical solution: a polycrystalline silicon production control system and a control method, the polycrystalline silicon production control system comprises a control device cooperating with a reduction furnace; the control device comprises a voltage detection module, a logic module and an execution module; the voltage detection module is at least used for detecting the voltage parameter of the reduction furnace, and sending the voltage parameter to the logic module; the logic module is at least used for judging whether the voltage parameter fluctuates or is abnormal, and sending the judgment result to the execution module; the execution module is at least used for adjusting the feed ratio of the reduction furnace when the voltage parameter is judged to fluctuate or be abnormal.

[0005] The above patent can discover whether there is an abnormal situation in the reduction furnace, whether the feed ratio is appropriate, and adjust it in time, but still has the following deficiencies:

[0006] Firstly, in the above scheme, when the actual voltage trend deviates from the predetermined trend, the computer issues an adjustment instruction, but the adjustment program has no "upper and lower limit adjustment space", and the instruction can only be executed once. When the actual voltage trend continues to deviate from the predetermined trend, the program cannot adjust. Secondly, the above scheme lacks a "voltage ignore range", and the program is always detecting and adjusting, which can cause large fluctuations in the intake amount. Finally, the scheme lacks a control program for the "atomization" phenomenon caused by the rapid reaction in the reduction furnace and a control program for the maximum tail gas temperature limit value of the reduction furnace. The above method is only used as a basic control for the production of the reduction furnace in actual application, and manual intervention is still required for adjustment, which cannot achieve automation of the reduction furnace in the whole operation cycle. SUMMARY

[0007] The present application aims to solve the problems of low automation control rate and poor control effect in the production process of the polycrystalline silicon reduction furnace, and proposes a full-automatic intelligent control system for the polycrystalline silicon reduction furnace, and a full-automatic intelligent control method for the polycrystalline silicon reduction furnace, so as to improve the automation control rate of the reduction furnace, ensure the stability of the polycrystalline silicon reduction furnace production and the reproducibility and repeatability of the index data.

[0008] In order to achieve the above-mentioned application purposes, the technical solutions of the present application are as follows:

[0009] A full-automatic intelligent control system for a polycrystalline silicon reduction furnace, comprising:

[0010] A control device matched with the reduction furnace, wherein the control device comprises a control panel and a voltage detection module, a tail gas temperature detection module, a logic processing module and an execution module electrically connected with the control panel;

[0011] The control panel is used at least for setting important process control parameters and displaying the current operation condition of the reduction furnace; the voltage detection module is used for detecting the voltage parameter in the reduction furnace, and when the measured voltage parameter deviates from the standard reference voltage value, the execution module adjusts the hydrogen intake amount according to the set control strategy;

[0012] The tail gas temperature detection module is used for detecting the tail gas temperature parameter in the reduction furnace, and when the measured tail gas temperature fluctuates, the execution module adjusts the intake amounts of hydrogen and chlorosilane according to the set control strategy.

[0013] Further, the logic processing module is connected with the control panel, the voltage detection module, the tail gas temperature detection module and the execution module through electrical signals, and is used at least for processing the signal input of the voltage detection module and the tail gas temperature detection module and outputting the results to the execution module; the execution module is connected with the feed adjustment valves of hydrogen and chlorosilane, and is used for controlling the feed flow of hydrogen and chlorosilane.

[0014] Furthermore, in one embodiment, the control panel includes an automatic voltage control module, on which parameters can be set and adjusted, including:

[0015] The time period of the reaction stage, the voltage deviation range corresponding to each reaction stage, the negligible range of the voltage deviation value, the amount of hydrogen adjustment corresponding to different voltage deviation ranges, and the upper and lower limits of the amount of hydrogen adjustment per time.

[0016] Furthermore, in one embodiment, the control panel includes an automatic exhaust gas temperature control module, wherein parameters that can be set and adjusted for each reaction stage in the automatic exhaust gas temperature control module include:

[0017] Exhaust gas temperature change time: This indicates the time interval for detecting the trend of exhaust gas temperature change.

[0018] The amplitude of exhaust gas temperature over the time of change: used in conjunction with the time of change as a basis for determining whether to trigger hydrogen adjustment;

[0019] Exhaust gas temperature judgment time: This refers to the time period during which the exhaust gas temperature fluctuation is captured after each hydrogen adjustment.

[0020] The amount of temperature adjustment in the exhaust gas within the judgment time: This represents the amount of change in exhaust gas temperature after each hydrogen adjustment. It is used in conjunction with the judgment time as a basis for judging whether the exhaust gas temperature is controllable.

[0021] The exhaust gas temperature reaches the amplitude-triggered hydrogen adjustment amount and the high and low limits of the hydrogen adjustment amount;

[0022] In addition, the exhaust gas temperature amplitude that triggers chlorosilane adjustment, the amount of a single chlorosilane adjustment, and the minimum cumulative reduction limit for chlorosilane.

[0023] Furthermore, in one embodiment, the control panel includes a maximum exhaust gas temperature limit panel, and the parameters that can be set and adjusted in the maximum exhaust gas temperature limit panel include:

[0024] The upper limit of exhaust gas temperature, the judgment time for exhaust gas temperature exceeding the upper limit, the single adjustment amount of chlorosilane, and the lower limit of cumulative reduction of chlorosilane.

[0025] Based on the aforementioned control system, this invention also provides a fully automatic intelligent control method for a polysilicon reduction furnace, including:

[0026] The automatic control process of the reduction furnace is divided into several stages based on the reaction time, and the control strategy for each stage can be set or adjusted independently. Automatic voltage control, automatic tail gas temperature control, and maximum tail gas temperature limit control are implemented for each stage.

[0027] Automatic voltage control refers to monitoring the voltage deviation between the operating voltage of the reduction furnace and the standard reference voltage, and matching the corresponding hydrogen adjustment amount according to different voltage deviation values ​​to stabilize the operating voltage within the set deviation range.

[0028] Automatic tail gas temperature control refers to monitoring the tail gas temperature fluctuation in the reduction furnace and matching the corresponding hydrogen and chlorosilane adjustment amounts according to different tail gas temperature fluctuations to ensure that the tail gas temperature reaches the set adjustment range.

[0029] The maximum exhaust gas temperature limit control continuously monitors the maximum exhaust gas temperature and adjusts the chlorosilane intake to ensure the gas field temperature for the reduction furnace reaction.

[0030] Furthermore, the hydrogen quantity adjustment process during the automatic exhaust gas temperature control includes:

[0031] If the exhaust gas temperature reaches the preset amplitude within the preset change time, the hydrogen quantity adjustment is triggered. After adjustment, the exhaust gas temperature is judged to be under control based on whether the exhaust gas temperature reaches the preset pullback amount within the judgment time. The hydrogen quantity adjustment within a single reaction stage is controlled by high and low limits.

[0032] Furthermore, the chlorosilane adjustment process in the automatic control of exhaust gas temperature includes: if the exhaust gas temperature reaches amplitude two within a preset change time, the silane quantity adjustment is triggered. After adjustment, the exhaust gas temperature is judged to be under control based on whether the exhaust gas temperature within the judgment time reaches the preset callback amount. The chlorosilane adjustment amount within a single reaction stage is controlled by the lower limit value.

[0033] Furthermore, the automatic voltage control program and the automatic exhaust gas temperature control program can be put into operation simultaneously or selected to be put into operation sequentially according to the actual operating conditions.

[0034] Furthermore, when both automatic voltage control and automatic exhaust gas temperature control are in operation, if the exhaust gas temperature is uncontrollable, the hydrogen quantity adjustment in the voltage control program is temporarily suspended, and the hydrogen quantity adjustment in the exhaust gas temperature control program is matched first.

[0035] In summary, the present invention has the following advantages:

[0036] 1. The control method of this invention mainly includes three aspects: First, by adjusting the PID control around the standard reference voltage and matching the corresponding hydrogen quantity; second, by adjusting the hydrogen quantity and chlorosilane quantity by controlling the amplitude of the tail gas temperature; and third, by controlling the highest peak value of the tail gas temperature to ensure the gas field temperature of the reduction furnace reaction. The system automatically regulates the hydrogen and chlorosilane intake quantities based on the operating voltage and tail gas temperature of the reduction furnace according to the preset control strategy, which can almost realize the automatic control of the entire operating cycle of the reduction furnace and improve the automation control rate of the reduction furnace.

[0037] 2. The present invention divides the intelligent control process of polysilicon reduction furnace into several stages according to the reaction time. Each stage can be set and adjusted by the control system. By subdividing the control stages, the control of the intelligent program is made more refined.

[0038] 3. This invention improves both the automation control system and its level, while ensuring stable operation of the polysilicon reduction furnace and the reproducibility and repeatability of key performance indicators. Through this control system and method, the average power consumption per production cycle does not differ by more than 2%.

[0039] 4. In this invention, the reduction furnace can respond and intervene in a timely manner according to changes in voltage and tail temperature during operation.

[0040] By continuously optimizing the process conditions table and under stable system operating conditions, the reasonable matching of air intake, current, and voltage can ensure that "atomization" does not occur in the first 15 hours of operation of the reduction furnace.

[0041] 5. This invention can select the timing of the automatic voltage control program and the automatic tail gas temperature control program according to the operating conditions of the reduction furnace. For example, in this scheme, there will be no atomization phenomenon in the first 15 hours of operation of the reduction furnace (empirical value), so only the "intelligent voltage control program" is put into operation for regulation, which can be unaffected by the "intelligent tail gas temperature control"; after 15 hours, the "intelligent tail gas temperature control" is put into operation for intelligent intervention, which can control atomization.

[0042] 6. This invention can eliminate misoperation and safety accidents caused by human intervention in the polysilicon reduction furnace production process, effectively avoiding human accidents. It can not only realize the full automation control of the reduction furnace production process, but also optimize production indicators, reduce costs and increase efficiency.

[0043] 7. In the control system of the present invention, the control variables involved, such as "change time", "hydrogen adjustment amount", "judgment time" and "return amount", can be adjusted on the control panel according to the characteristics of different reduction furnaces. After running for a period of time, these variables can be fixed. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the automatic voltage control process of the present invention;

[0045] Figure 2 This is a schematic diagram of the tail temperature control process of the present invention;

[0046] Figure 3 This is a schematic diagram of the control panel of the present invention. Detailed Implementation

[0047] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention. The terms "first," "second," etc., used in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, or apparatuses.

[0048] Example 1

[0049] This embodiment provides a fully automatic intelligent control method for a polysilicon reduction furnace, which is based on a fully automatic control system for the polysilicon reduction furnace. The control system includes a control device that works in conjunction with the reduction furnace. The control device includes a control panel and a voltage detection module, a tail gas temperature detection module, a logic processing module, and an execution module electrically connected to the control panel.

[0050] The voltage detection module is used to detect the voltage parameters inside the reduction furnace. When the measured voltage parameters deviate from the standard reference voltage value in the system, the execution module adjusts the hydrogen intake according to the set control strategy.

[0051] The exhaust gas temperature detection module is used to detect the exhaust gas temperature parameters in the reduction furnace. When the measured exhaust gas temperature fluctuates, the execution module adjusts the intake volume of hydrogen and chlorosilane according to the set control strategy.

[0052] The logic processing module is connected to the control panel, voltage detection module, exhaust gas temperature detection module, and execution module via electrical signals. It is used at least to process and judge the signal inputs from the voltage detection module and exhaust gas temperature detection module, and then output the judgment result to the execution module.

[0053] The execution module is connected to the feed regulating valves for hydrogen and chlorosilane to control the feed flow rate of hydrogen and chlorosilane.

[0054] The control panel is primarily used to set important process control parameters and display the current operating status of the reduction furnace. Specifically, for example... Figure 3The diagram shows a typical control panel design. The control panel comprises three main sections: automatic voltage control, automatic exhaust gas temperature control, and maximum exhaust gas temperature limit. In this embodiment, the reduction furnace operation is divided into seven stages based on reaction time. For each different reaction stage, the control parameters for the amounts of hydrogen and chlorosilane can be adjusted at the corresponding locations on the control panel.

[0055] In the automatic voltage control module, the following changes can be set and adjusted:

[0056] ① Time span of the reaction phase: The duration of each reaction phase can be divided and set by the user;

[0057] ② Voltage deviation range for each reaction stage: The corresponding hydrogen adjustment amount can be matched according to different voltage deviation ranges;

[0058] ③ Negligible range of voltage deviation: When the voltage deviation is within this negligible range, the amount of hydrogen will not be adjusted;

[0059] ④ Hydrogen adjustment amount corresponding to different voltage deviation ranges: The corresponding hydrogen adjustment amount can be matched according to the voltage deviation range into which the voltage deviation value falls;

[0060] ⑤ High and low limits for single hydrogen adjustment: The amount of hydrogen added or reduced each time shall not exceed the set high and low limits.

[0061] The exhaust gas temperature automatic control module includes control parameter settings for hydrogen and chlorosilane adjustments. In the hydrogen adjustment control parameter setting area, the adjustable parameters for each reaction stage include:

[0062] ① Time interval for detecting exhaust gas temperature change: The time interval for detecting the trend of exhaust gas temperature change can be freely selected;

[0063] ② Amplitude of exhaust gas temperature over the time of change: This amplitude, combined with the time of change, serves as the basis for determining whether hydrogen adjustment is triggered; for example, see attached... Figure 3 The corresponding increases are "Amplitude 1" and "Amplitude 3", and the corresponding decreases are "Amplitude 2".

[0064] ③ Time for judging exhaust gas temperature: The time period for capturing the fluctuation range of exhaust gas temperature after each hydrogen adjustment.

[0065] ④ The amount of temperature adjustment in the exhaust gas within the judgment time: The amount of change in exhaust gas temperature after each hydrogen adjustment needs to be combined with the judgment time as the basis for judging whether the exhaust gas temperature is controllable. If the exhaust gas temperature reaches the adjustment amount within the judgment time, it means that the exhaust gas temperature is controllable; if it does not reach it, it is considered uncontrollable.

[0066] ⑤ Hydrogen adjustment amount: Set the corresponding "add H2 amount" or "decrease H2 amount" according to the amplitude of the tail gas temperature change over the time.

[0067] ⑥ High and low limits for hydrogen adjustment: Based on the actual situation of each reaction stage, the high and low limits for hydrogen adjustment can be given by the user.

[0068] When the exhaust gas temperature rises rapidly and the temperature remains uncontrollable even after automatic hydrogen adjustment, the chlorosilane intake rate can be adjusted. In the chlorosilane adjustment control parameter setting area, the following variables can be set and adjusted for each reaction stage: the exhaust gas temperature fluctuation that triggers chlorosilane adjustment, the amount of chlorosilane adjustment per instance, and the minimum cumulative reduction limit for chlorosilane.

[0069] The parameters that can be set and adjusted in the maximum exhaust temperature limit section include: the maximum exhaust temperature limit, the judgment time for the exhaust temperature exceeding the maximum limit, the single adjustment amount of chlorosilane, and the cumulative minimum reduction limit of chlorosilane.

[0070] Based on the aforementioned control system, this control method divides the automatic control process of the reduction furnace into several independent control stages according to the reaction time. Each stage is controlled independently without mutual interference. Depending on the operating characteristics of different reduction furnaces, each stage can be further subdivided into multiple smaller stages, allowing for regulation within shorter time periods during furnace operation, thus making the intelligent program control more precise.

[0071] Each control stage includes automatic voltage control, automatic exhaust gas temperature control, and maximum exhaust gas temperature limit control.

[0072] Automatic voltage control refers to the use of PID adjustment when the actual voltage in the furnace deviates from the reference voltage. This adjustment matches the amount of hydrogen supplied to the standard reference voltage to accelerate or inhibit the reaction rate, ensuring the actual voltage deviation remains stable within the set range. When the actual voltage deviates positively (i.e., the actual voltage is higher than the standard reference voltage), the control system automatically increases the hydrogen supply via the feed regulating valve; when the actual voltage deviates negatively (i.e., the actual voltage is lower than the standard reference voltage), the hydrogen supply is automatically reduced. Adjustment stops when the voltage is adjusted to a negligible range. This control process is repeated throughout the reduction furnace operation to ensure the actual voltage deviation remains stable within the set range.

[0073] Before the above-mentioned automatic voltage control process begins, control parameters can be set on the control panel. The settable control parameters are detailed in the section on automatic voltage control above, which describes the adjustable parameters. After setting, during the reduction furnace operation, the control system adjusts the hydrogen intake according to the voltage deviation between the detected actual voltage value and the preset standard reference voltage value, following the pre-defined control strategy.

[0074] Automatic tail gas temperature control refers to adjusting the amount of hydrogen and chlorosilane by regulating the amplitude of tail gas temperature fluctuations to keep the tail gas temperature within a preset range. The system can monitor the trend of tail gas temperature changes, obtain a piecewise temperature function by regressing the baseline temperature curve, and obtain the tail gas temperature change rate (slope) for each time period by calculating the first derivative. When the tail gas temperature "rises" during operation and the slope increases, the hydrogen / chlorosilane flow rate is adjusted in time to prevent severe atomization in the furnace, which would affect the growth rate. Ultimately, this reduces power consumption and increases the polycrystalline silicon deposition rate.

[0075] Before the automatic exhaust gas temperature control is activated, the corresponding control parameters can be set in the control panel. The settable control parameters are listed in the section on automatic exhaust gas temperature control above, which describes the adjustable parameters.

[0076] The hydrogen quantity adjustment process in the automatic exhaust gas temperature control process includes:

[0077] The system detects the trend of exhaust gas temperature change within each time interval. If the exhaust gas temperature reaches a preset amplitude value within a preset time interval, the hydrogen quantity adjustment is triggered. After adjustment, the system determines whether the exhaust gas temperature is under control based on whether the exhaust gas temperature reaches a preset pullback amount within the judgment time interval. The hydrogen quantity adjustment within a single reaction stage is controlled by high and low limits.

[0078] The chlorosilane adjustment process during the automatic control of exhaust gas temperature includes: if the exhaust gas temperature reaches amplitude two within a preset change time, the silane quantity adjustment is triggered. After adjustment, the exhaust gas temperature is judged to be under control based on whether the exhaust gas temperature reaches the preset callback amount within the judgment time. The chlorosilane adjustment amount within a single reaction stage is controlled by the lower limit value.

[0079] At each stage, the peak value of the exhaust gas temperature needs to be controlled. When the average exhaust gas temperature within the judgment time (given based on empirical values) exceeds the maximum limit of the exhaust gas temperature, the program can automatically adjust the amount of chlorosilane multiple times to ensure the gas field temperature of the reduction furnace reaction. The adjustment amount of chlorosilane continues until the lower limit is reached.

[0080] The automatic voltage control program and the automatic exhaust gas temperature control program can either run synchronously or be activated sequentially depending on the actual operating conditions. When both are running, if the exhaust gas temperature is uncontrollable, the hydrogen quantity adjustment in the voltage control program will be temporarily suspended, and the hydrogen quantity adjustment in the exhaust gas temperature control program will be prioritized.

[0081] Based on experience, the reduction furnace using this control scheme generally does not exhibit atomization before 15 hours. Therefore, intelligent intervention through tail temperature control can be implemented after 15 hours to control atomization. The reduction furnace operates automatically through a voltage automatic control program during the first 15 hours, unaffected by the tail gas temperature intelligent control program.

[0082] Example 2

[0083] This embodiment provides a fully automatic intelligent control method for a polysilicon reduction furnace. The control process of this method will be illustrated below through a specific case.

[0084] See appendix Figure 1 To be continued Figure 3 This scheme divides the operation of the reduction furnace into 7 stages based on time, and controls each stage accordingly. The process parameters used in each stage can be preset on the control panel. The voltage control and tail temperature control strategies for each stage are as follows:

[0085] The first stage (2h-15h) of the regulation process: set the voltage neglect range (-2V~1V), and within this neglect range, the hydrogen gas is not adjusted.

[0086] When the voltage deviation is ≤5V, the hydrogen adjustment amount is 5 times the standard square of the voltage deviation; when the voltage deviation is greater than 5V, the hydrogen adjustment amount is 10 times the standard square of the voltage deviation; the maximum hydrogen adjustment amount is the upper and lower limits.

[0087] When the exhaust gas temperature rises by more than 10°C within 30 minutes, the hydrogen quantity automatically increases by 50 standard cubic meters based on the set "H2 addition amount". The "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount can be automatically adjusted to the "H2 addition high limit" value. At this time, the hydrogen quantity adjustment in the voltage control program is temporarily suspended, prioritizing the control of the reduction furnace's "atomization". When the exhaust gas temperature rises by more than 15°C beyond the set value of "amplitude 3" within 30 minutes, the chlorosilane quantity automatically decreases by 5 standard cubic meters, subject to the "reduction TCS low limit" restriction. The corresponding "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature decrease trend is within a controllable range, and the chlorosilane low limit value is reduced until it is reached.

[0088] The second stage (15h-25h) of the regulation process: Within the voltage neglect range (-2V~2V), no hydrogen adjustment is made; when the voltage deviation is ≤5V, the hydrogen adjustment is 5 times the standard square of the voltage deviation; when 5V < voltage deviation ≤10V, the hydrogen adjustment is 10 times the standard square of the voltage deviation; when greater than 10V < voltage deviation ≤15V, the hydrogen adjustment is 15 times the standard square of the voltage deviation; the hydrogen adjustment ranges from the maximum to the minimum.

[0089] If the exhaust gas temperature rises by more than 10°C within 60 minutes, the "H2 addition amount" will automatically increase by 50 standard cubic meters. The "judgment time" and "rebound amount" will be used to determine if the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount will automatically adjust to the "H2 addition high limit" value. At this time, the hydrogen quantity adjustment in the voltage control program will be temporarily suspended, prioritizing the control of the reduction furnace's "atomization". If the exhaust gas temperature rises by more than 15°C beyond the "amplitude 3" setting within 60 minutes, the chlorosilane quantity will automatically decrease by 10 standard cubic meters. Subject to the "reduction TCS low limit" restriction, the "judgment time" and "rebound amount" will be used to determine if the exhaust gas temperature decrease trend is within a controllable range, and the chlorosilane low limit will be reduced until it is reached.

[0090] The third stage (25h-35h) of the regulation process: Within the voltage negligible range (-2V~2V), no hydrogen adjustment is made; when the voltage is fast or slow ≤ 5V, the hydrogen adjustment is 10 times the standard square of the voltage deviation; when 5V < voltage deviation ≤ 10V, the hydrogen adjustment is 15 times the standard square of the voltage deviation; when 10 < voltage deviation ≤ 15V, the hydrogen adjustment is 20 times the standard square of the voltage deviation; the hydrogen adjustment ranges from the maximum to the minimum.

[0091] When the exhaust gas temperature rises by more than 10°C within 60 minutes, the "H2 addition amount" automatically increases by 50 standard cubic meters. The "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount can be automatically adjusted to the "H2 addition high limit" value. When the exhaust gas temperature drops by more than 10°C within 60 minutes, the "H2 reduction amount" automatically decreases by 20 standard cubic meters. The "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount can be automatically adjusted to the "H2 reduction low limit" value. At this time, in the voltage control program, the hydrogen amount is temporarily suspended, and priority is given to controlling the reduction furnace "atomization". When the exhaust gas temperature rises by more than 15°C above the "amplitude 3" set value within 60 minutes, the chlorosilane amount automatically decreases by 10 standard cubic meters. Subject to the "TCS reduction low limit" restriction, the "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature decrease trend is within a controllable range, and the chlorosilane low limit is reduced until it is reached.

[0092] Phase 4 (35h-50h) Control Process: Within the voltage negligible range (-2V~2V), no hydrogen adjustment is made; when the voltage is fast or slow ≤ 5V, the hydrogen adjustment is 10 times the standard square of the voltage deviation; when 5V < voltage deviation ≤ 10V, the hydrogen adjustment is 15 times the standard square of the voltage deviation; when 10V < voltage deviation ≤ 15V, the hydrogen adjustment is 20 times the standard square of the voltage deviation; the hydrogen adjustment ranges from the maximum to the minimum.

[0093] When the exhaust gas temperature rises by more than 10°C within 60 minutes, the "H2 addition amount" automatically increases by 50 standard cubic meters. The "judgment time" and "rebound amount" determine whether the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount automatically adjusts to the "H2 addition high limit" value. When the exhaust gas temperature drops by more than 10°C within 60 minutes, the "H2 reduction amount" automatically decreases by 10 standard cubic meters. The "judgment time" and "rebound amount" determine whether the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount automatically adjusts to the "H2 reduction low limit" value. At this time, the hydrogen amount is temporarily suspended in the voltage control program, prioritizing the control of the reduction furnace's "atomization". When the exhaust gas temperature rises by more than 15°C beyond the "amplitude 3" setting within 60 minutes, the chlorosilane amount automatically decreases by 10 standard cubic meters. Subject to the "TCS reduction low limit" restriction, the "judgment time" and "rebound amount" determine whether the exhaust gas temperature's downward trend is within a controllable range, and the chlorosilane low limit is reduced until it is reached.

[0094] Fifth stage (50h-65h) control process: Within the voltage negligible range (-2V~2V), no hydrogen adjustment is made; when the voltage fast or slow is ≤5V, the hydrogen adjustment is 10 times the standard square of the voltage deviation; when 5V < voltage deviation ≤10V, the hydrogen adjustment is 15 times the standard square of the voltage deviation; when 10V < voltage deviation ≤15V, the hydrogen adjustment is 20 times the standard square of the voltage deviation; the hydrogen adjustment ranges from the maximum to the minimum.

[0095] When the exhaust gas temperature rises by more than 10°C within 60 minutes, the "H2 addition amount" automatically increases by 50 standard cubic meters. The "judgment time" and "rebound amount" determine whether the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount automatically adjusts to the "H2 addition high limit" value. When the exhaust gas temperature drops by more than 10°C within 60 minutes, the "H2 reduction amount" automatically decreases by 10 standard cubic meters. The "judgment time" and "rebound amount" determine whether the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount automatically adjusts to the "H2 reduction low limit" value. At this time, the hydrogen amount is temporarily suspended in the voltage control program, prioritizing the control of the reduction furnace's "atomization". When the exhaust gas temperature rises by more than 15°C beyond the "amplitude 3" setting within 60 minutes, the chlorosilane amount automatically decreases by 10 standard cubic meters. Subject to the "TCS reduction low limit" restriction, the "judgment time" and "rebound amount" determine whether the exhaust gas temperature's downward trend is within a controllable range, and the chlorosilane low limit is reduced until it is reached.

[0096] Phase 6 (65h-80h) Control Process: Within the voltage negligible range (-2V~2V), no hydrogen adjustment is made; when the voltage fast or slow is ≤5V, the hydrogen adjustment is 10 times the standard square of the voltage deviation; when 5V < voltage deviation ≤10V, the hydrogen adjustment is 15 times the standard square of the voltage deviation; when 10V < voltage deviation ≤15V, the hydrogen adjustment is 20 times the standard square of the voltage deviation; the hydrogen adjustment ranges from the maximum to the minimum.

[0097] When the exhaust gas temperature rises by more than 10°C within 60 minutes, the "H2 addition amount" automatically increases by 50 standard cubic meters. The "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount can be automatically adjusted to the "H2 addition high limit" value. When the exhaust gas temperature drops by more than 10°C within 60 minutes, the "H2 reduction amount" automatically decreases by 20 standard cubic meters. The "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount can be automatically adjusted to the "H2 reduction low limit" value. At this time, in the voltage control program, the hydrogen amount is temporarily suspended, and priority is given to controlling the reduction furnace "atomization". When the exhaust gas temperature rises by more than 15°C above the "amplitude 3" set value within 60 minutes, the chlorosilane amount automatically decreases by 10 standard cubic meters. Subject to the "TCS reduction low limit" restriction, the "judgment time" and "rebound amount" are used to determine if the exhaust gas temperature decrease trend is within a controllable range, and the chlorosilane low limit is reduced until it is reached.

[0098] Phase 7 (80h-100h) Control Process: Within the voltage negligible range (-2V~2V), no hydrogen adjustment is made; when the voltage fast or slow is ≤5V, the hydrogen adjustment is 15 times the standard square of the voltage deviation; when 5V < voltage deviation ≤10V, the hydrogen adjustment is 20 times the standard square of the voltage deviation; when 10V < voltage deviation ≤15V, the hydrogen adjustment is 25 times the standard square of the voltage deviation; the hydrogen adjustment ranges from the maximum to the minimum.

[0099] When the exhaust gas temperature rises by more than 10°C within 60 minutes, the "H2 addition amount" automatically increases by 50 standard cubic meters. The "judgment time" and "rebound amount" determine whether the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount automatically adjusts to the "H2 addition high limit" value. When the exhaust gas temperature drops by more than 10°C within 60 minutes, the "H2 reduction amount" automatically decreases by 10 standard cubic meters. The "judgment time" and "rebound amount" determine whether the exhaust gas temperature is controllable. If not, the maximum hydrogen adjustment amount automatically adjusts to the "H2 reduction low limit" value. At this time, the hydrogen amount is temporarily suspended in the voltage control program, prioritizing the control of the reduction furnace's "atomization". When the exhaust gas temperature rises by more than 15°C beyond the "amplitude 3" setting within 60 minutes, the chlorosilane amount automatically decreases by 10 standard cubic meters. Subject to the "TCS reduction low limit" restriction, the "judgment time" and "rebound amount" determine whether the exhaust gas temperature's downward trend is within a controllable range, and the chlorosilane low limit is reduced until it is reached.

[0100] During the operation and control of the reduction furnace, it can respond and intervene in a timely manner according to changes in voltage and tail temperature. After the fourth stage begins, the tail gas temperature gradually decreases, and the hydrogen automatically decreases according to the settings. If the tail temperature rises, the hydrogen also automatically rises.

[0101] Whether it's voltage control or tail temperature control, the relevant control variables, such as "change time," "hydrogen adjustment amount," "high and low limits," "judgment time," and "reverse amount," can all be adjusted arbitrarily on the control panel. Depending on the characteristics of different reduction furnaces and the production conditions of each company, these variables can be fixed after a period of operation. The parameter settings in the attached diagram are for illustrative purposes only and are not intended to limit the invention.

[0102] Using the above control methods, the reduction furnace production process can be fully controlled sequentially. The computer sets the process conditions according to the table, and by setting the correctable range, the system program automatically adjusts and corrects. Ultimately, 100% automation control of the reduction furnace can be achieved.

[0103] This solution, through the development of a fully automated intelligent control system program, effectively avoids human error. It not only enables fully automated control of the reduction furnace production process but also optimizes production indicators, reducing costs and increasing efficiency. This control method improves both the automation system and its level, while ensuring the stable operation of the polysilicon reduction furnace and the replicability and reproducibility of its performance data.

[0104] Using this control method, the average power consumption per production cycle will not differ by more than 2%; the one-time conversion rate of polysilicon can reach 12%-13%; the deposition rate can be increased by 12.5-15%, the density can reach 55-70%, the success rate of operation can be increased by 25%, and the labor intensity of personnel can be reduced by 60-70%. Based on an annual production of 50,000 tons of polysilicon, at least 560,000 manual operations per employee can be reduced throughout the year.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A fully automatic intelligent control system for a polycrystalline silicon reduction furnace, characterized in that, include: A control device that works in conjunction with a reduction furnace, the control device including a control panel and a voltage detection module, a tail gas temperature detection module, a logic processing module and an execution module electrically connected to the control panel; The control panel is used at least to set important process control parameters and display the current operating status of the reduction furnace; the voltage detection module is used to detect the voltage parameters in the reduction furnace. When the measured voltage parameters deviate from the standard reference voltage value, the execution module adjusts the hydrogen intake according to the set control strategy. The exhaust gas temperature detection module is used to detect the exhaust gas temperature parameters in the reduction furnace. When the measured exhaust gas temperature fluctuates, the execution module adjusts the intake volume of hydrogen and chlorosilane according to the set control strategy. The control panel includes an automatic voltage control section, where parameters that can be set and adjusted include: The time period of the reaction stage, the voltage deviation range corresponding to each reaction stage, the negligible range of the voltage deviation value, the amount of hydrogen adjustment corresponding to different voltage deviation ranges, and the upper and lower limits of the amount of hydrogen adjustment in a single instance. The control panel includes an automatic exhaust gas temperature control module, which allows for the setting and adjustment of various parameters for different reaction stages, including: Exhaust gas temperature change time: This indicates the time interval for detecting the trend of exhaust gas temperature change. The amplitude of exhaust gas temperature over the time of change: used in conjunction with the time of change as a basis for determining whether to trigger hydrogen adjustment; Exhaust gas temperature judgment time: This refers to the time period during which the exhaust gas temperature fluctuation is captured after each hydrogen adjustment. The amount of temperature adjustment in the exhaust gas within the judgment time: This represents the amount of change in exhaust gas temperature after each hydrogen adjustment. It is used in conjunction with the judgment time as a basis for judging whether the exhaust gas temperature is controllable. The exhaust gas temperature reaches the amplitude-triggered hydrogen adjustment amount and the high and low limits of the hydrogen adjustment amount; In addition, the exhaust gas temperature amplitude that triggers chlorosilane adjustment, the amount of a single chlorosilane adjustment, and the minimum cumulative reduction limit for chlorosilane.

2. The fully automatic intelligent control system for a polycrystalline silicon reduction furnace according to claim 1, characterized in that, The logic processing module is connected to the control panel, voltage detection module, exhaust gas temperature detection module, and execution module via electrical signals. It is used at least to process the signal inputs from the voltage detection module and exhaust gas temperature detection module and output the results to the execution module. The execution module is connected to the feed regulating valves for hydrogen and chlorosilane and is used to control the feed flow rate of hydrogen and chlorosilane.

3. The fully automatic intelligent control system for a polycrystalline silicon reduction furnace according to claim 1, characterized in that, The control panel includes a section for setting and adjusting the maximum exhaust temperature limit. The parameters that can be set and adjusted in this section include: The upper limit of exhaust gas temperature, the judgment time for exhaust gas temperature exceeding the upper limit, the single adjustment amount of chlorosilane, and the lower limit of cumulative reduction of chlorosilane.

4. A fully automatic intelligent control method for a polycrystalline silicon reduction furnace, implemented using the control system described in any one of claims 1-3, characterized in that, include: The automatic control process of the reduction furnace is divided into several stages according to the reaction time, and the control strategy for each stage can be set or adjusted separately. Automatic voltage control, automatic exhaust gas temperature control, and maximum exhaust gas temperature limit control are implemented for each stage. Automatic voltage control refers to monitoring the voltage deviation between the operating voltage of the reduction furnace and the standard reference voltage, and matching the corresponding hydrogen adjustment amount according to different voltage deviation values ​​to stabilize the operating voltage within the set deviation range. Automatic tail gas temperature control refers to monitoring the tail gas temperature fluctuation in the reduction furnace and matching the corresponding hydrogen and chlorosilane adjustment amounts according to different tail gas temperature fluctuations to ensure that the tail gas temperature reaches the set adjustment range. The maximum exhaust gas temperature limit control continuously monitors the maximum exhaust gas temperature and adjusts the chlorosilane intake to ensure the gas field temperature of the reduction furnace reaction.

5. The fully automatic intelligent control method for a polycrystalline silicon reduction furnace according to claim 4, characterized in that, The hydrogen quantity adjustment process during automatic exhaust gas temperature control includes: If the exhaust gas temperature reaches the preset amplitude within the preset change time, the hydrogen quantity adjustment is triggered. After adjustment, the exhaust gas temperature is judged to be under control based on whether the exhaust gas temperature reaches the preset pullback amount within the judgment time. The hydrogen quantity adjustment within a single reaction stage is controlled by high and low limits.

6. The fully automatic intelligent control method for a polycrystalline silicon reduction furnace according to claim 4, characterized in that, The chlorosilane adjustment process during the automatic control of exhaust gas temperature includes: if the exhaust gas temperature reaches amplitude two within a preset change time, the silane quantity adjustment is triggered. After adjustment, the exhaust gas temperature is judged to be under control based on whether the exhaust gas temperature reaches the preset callback amount within the judgment time. The chlorosilane adjustment amount within a single reaction stage is controlled by the lower limit value.

7. The fully automatic intelligent control method for a polycrystalline silicon reduction furnace according to claim 4, characterized in that, The automatic voltage control program and the automatic exhaust gas temperature control program can be put into operation simultaneously or selected to be put into operation sequentially according to the actual operating conditions.

8. The fully automatic intelligent control method for a polycrystalline silicon reduction furnace according to claim 7, characterized in that, When both automatic voltage control and automatic exhaust gas temperature control are in operation, if the exhaust gas temperature is uncontrollable, the hydrogen quantity adjustment in the voltage control program is temporarily suspended, and the hydrogen quantity adjustment in the exhaust gas temperature control program is matched first.

Images