Method for controlling polycrystalline silicon reduction tail gas amount
By dividing the operation of the polysilicon reduction furnace into multiple production stages and calculating the tail gas reduction based on the basic quantities of each stage, the problem of untimely tail gas reduction in the existing technology is solved, achieving rapid and safe tail gas control and ensuring the safety of products in the reduction furnace and the continuity of production.
Patent Information
- Application Number
- CN202510923681.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-04
- Publication Date
- 2025-10-28
AI Technical Summary
In emergency situations, existing technologies cannot reduce the exhaust gas volume of polysilicon reduction furnaces in a timely and accurate manner, leading to product loss or shutdown within the furnace and failing to meet emergency needs.
The operation of the reduction furnace is divided into multiple production stages. The TCS and current baseline values for different stages are set, and the amount of tail gas that can be reduced in each stage is calculated based on these baseline values. The reduction amounts are accumulated in order of priority until the total reduction amount is reached, ensuring the safety of the product in each stage.
It enables rapid and safe reduction of exhaust gas volume in emergency situations, protecting products inside the reduction furnace, avoiding downtime and product loss, and meeting production needs.
Smart Images
Figure CN120846098A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of exhaust gas control technology in polysilicon production, and specifically to a method for controlling the amount of exhaust gas from polysilicon reduction. Background Technology
[0002] The raw materials for producing polycrystalline silicon using the fluidized bed method are TCS (trichlorosilane) and... The process utilizes electric heating to reduce TCS to polycrystalline silicon. The reduction furnace in the entire production line has feeding and exhaust functions; TCS and polycrystalline silicon are input at the feeding end. The exhaust end discharges exhaust gas, which also contains TCS and Therefore, the exhaust gas needs to enter subsequent processes for separation and other operations to remove TCS and other pollutants from the exhaust gas. It is then fed back into the reduction furnace for recycling, thereby reducing losses.
[0003] Then, in actual production, if a fault occurs in the subsequent process of treating the exhaust gas and it is necessary to reduce the amount of exhaust gas received, the amount of exhaust gas in the reduction furnace needs to be reduced in a timely manner.
[0004] Currently, the method for significantly reducing the total exhaust gas volume of reduction furnaces is to manually adjust the exhaust gas volume of each reduction furnace individually, and then sum up the adjusted exhaust gas volumes of all reduction furnaces until the required reduction volume is achieved.
[0005] The above operating methods have objective factors such as insufficient operating time due to emergencies, employee skills, and inconsistent operating stages of each reduction furnace, which can lead to problems such as untimely reduction, incorrect reduction, furnace atomization, rod cracking, rod collapse, and inability to restart after rod extinguishing. Ultimately, they can neither meet emergency requirements nor preserve the existing products in the furnace. Summary of the Invention
[0006] To address the technical problem in existing technologies where, due to objective factors in emergency situations, the reduction gas reduction not only fails to meet emergency requirements but also fails to preserve existing products within the reduction furnace, this invention provides a method for controlling the polysilicon reduction gas volume. This method divides the operation of all reduction furnaces into multiple distinct stages, and sets different TCS reduction rates for each stage. The reduction in flow rate and current allows for rapid reduction of the reduction tail gas in emergency situations, thereby meeting emergency requirements and ensuring the safety of products inside the reduction furnace.
[0007] The technical solution of this invention is:
[0008] A method for controlling the amount of polysilicon reduction tail gas includes:
[0009] Step S10: Based on the production status of polysilicon in the reduction furnace, the operation of the reduction furnace is divided into multiple production stages.
[0010] Step S20: Set the basic TCS quantity required for the reduction furnace in different production stages. Basic quantities and current basic quantities, and based on TCS basic quantities, The basic quantity and current basic quantity are used to calculate the reducible tail gas volume of the reduction furnace in all production stages. This reducible tail gas volume is the fractional reduction volume.
[0011] Step S30: Set the priority for reducing tail gas in reduction furnaces at different production stages;
[0012] Step S40: Determine the total reduction of the reduction tail gas. According to the priority order of tail gas reduction in step S30, the reduction of the reduction furnace in different production stages is accumulated sequentially until the sum of all reductions is greater than or equal to the total reduction, at which point the accumulation stops.
[0013] Step S50: Determine the lowest priority production stage among all production stages requiring tail gas reduction. Within this production stage, identify the last reduction furnace with the last accumulated reduction amount, calculate the TCS reduction of this reduction furnace, and determine the appropriate reduction amount based on the TCS reduction. Dropout and current dropout;
[0014] Among them, the final TCS amount of the reduction furnace in each production stage, The final quantity and the final current quantity are respectively greater than the TCS baseline quantity of the reduction furnace. Basic quantities and current basic quantities.
[0015] Optionally, in step S10, the operation of the reduction furnace includes at least three production stages: initial, intermediate, and final. The priority of tail gas reduction in the final stage is higher than that in the initial stage, and the priority of tail gas reduction in the initial stage is higher than that in the intermediate stage.
[0016] Optionally, the baseline TCS final value in the initial and final stages can both be 0, while the baseline TCS final value in the intermediate stage is greater than 0.
[0017] Optionally, in step S10, the different production stages of the reduction furnace are divided according to the different working time periods of the reduction furnace.
[0018] Optionally, when reducing the tail gas of the reduction furnace in the final stage, all reduction furnaces in the final stage are sorted according to their working time, and the tail gas reduction operation is performed in order from longest to shortest working time.
[0019] Optionally, when reducing the tail gas of the reduction furnace in the initial stage, all reduction furnaces in the initial stage are sorted according to their working time, and the tail gas reduction operation is performed in order from shortest to longest working time.
[0020] Optionally, the TCS reduction is equal to the difference between the current TCS value and the base TCS value.
[0021] Optionally, the The reduction is equal to the product of the TCS reduction and the raw material ratio, wherein the raw material ratio is: The ratio of the current quantity to the current quantity of the TCS.
[0022] Optionally, when present in a reduction furnace during one of the production stages: Current quantity - Decrease ≥ The base quantity indicates that the sum of all the individual decreases is greater than or equal to the total decrease.
[0023] Optionally, the current drop is equal to the The product of the reduction in quantity and the power ratio.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] Based on the operation of different reduction furnaces, all reduction furnaces are divided into multiple production stages. Then, the impact of the products in the reduction furnaces at different stages on TCS is determined. And the minimum current requirement, and then based on the determined TCS baseline quantity, The baseline quantity and current baseline quantity are used to determine the TCS reduction that can be achieved in each reduction furnace during each production stage. The reduction rate and current reduction rate are calculated, and the amount of tail gas that can be reduced in the reduction furnace during this production stage is set as the reduction rate.
[0026] Then, following a specific order, all individual reduction amounts are accumulated sequentially. When the sum of the accumulated individual reduction amounts is greater than or equal to the total reduction amount, the production stage of the last accumulated individual reduction amount is determined, and the TCS reduction amount of that production stage is calculated. The decrease in quantity and the decrease in current.
[0027] This technical solution can rapidly reduce exhaust gas emissions while ensuring the safety of the products in each reduction furnace, thus meeting both production and emergency needs. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 This is a flowchart of the process of the present invention. Detailed Implementation
[0030] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.
[0031] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0032] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0033] Example:
[0034] See Figure 1 This embodiment discloses a method for controlling the amount of polysilicon reduction tail gas, including the following steps:
[0035] Step S10: Based on the production status of polysilicon in the reduction furnace, the operation of the reduction furnace is divided into multiple production stages. Each production stage includes multiple reduction furnaces that are in operation. The production status of all reduction furnaces in each production stage is similar, while the production status of reduction furnaces in different production stages is significantly different.
[0036] Step S20: Set the basic TCS quantity required for the reduction furnace in different production stages. Basic quantities and current basic quantities, including the set basic quantity of the reduction furnace TCS, The basic quantity and current basic quantity should meet the minimum production requirements in the current reduction furnace.
[0037] Since the production status of all reduction furnaces within each production stage is similar but not identical, the basic TCS quantity of all reduction furnaces in each production stage... There are differences between the basic quantities and the basic current quantities, specifically in that their values are different.
[0038] Based on the TCS baseline of each reduction furnace, The basic quantity and current basic quantity are used to calculate the reducible tail gas volume of the reduction furnace during the production stage of this reduction furnace. This reducible tail gas volume is a partial reduction volume, due to the TCS basic quantity of each reduction furnace, The basic quantity and the basic current quantity are different, so the specific reduction amount for each reduction furnace is also different.
[0039] Step S30: Set the priority of reducing tail gas in reduction furnaces at different production stages. In case of emergency, tail gas reduction operations should be carried out on reduction furnaces in different production stages in sequence according to the priority of tail gas reduction.
[0040] In step S40, before reducing the tail gas of the reduction furnaces in different production stages, it is first necessary to determine the total reduction amount of reduction tail gas. Then, according to the tail gas reduction priority order in step S30, it is determined which production stage's reduction furnaces need to reduce tail gas. The determination method is to compare the total reduction amount with the sum of the individual reduction amounts of all reduction furnaces within the production stage.
[0041] If there are n priority production stages, and the total reduction amount that the first priority production stage can reduce is A1, the total reduction amount that the second priority production stage can reduce is A2, and so on, if A1 ≥ the total reduction amount, then only the reduction of tail gas in the reduction furnace of the first priority production stage is reduced. If A1 ≤ the total reduction amount, then calculate whether A1 + A2 is greater than the total reduction amount. If yes, then reduce the tail gas in the reduction furnaces of the first and second priority production stages. If no, then continue to calculate whether A1 + A2 + A3 is greater than the total reduction amount, until A1 + A2 + ... + An ≥ the total reduction amount.
[0042] Generally, when an emergency occurs in the process of handling reduction exhaust gas, the total reduction of reduction exhaust gas can be determined in a short period of time.
[0043] After determining all production stages that require tail gas reduction, the reduction amounts of all reduction furnaces in the last priority production stage are sequentially accumulated until the sum of the reduction amounts of the previous priority production stages and the sum of the reduction amounts of the reduction furnaces accumulated in this production stage are greater than or equal to the total reduction amount.
[0044] For example, if A1 + A2 ≥ total reduction, then the reduction amounts of the reduction furnaces in the second priority production stage are accumulated sequentially until the sum of the reduction amounts of the reduction furnaces in the second priority production stage and A1 is greater than or equal to the total reduction. In this example, within the second priority production stage, the sum of the reduction amounts of some reduction furnaces and A1 may be greater than or equal to the total reduction. Therefore, within the second priority production stage, not all reduction furnaces necessarily need to reduce exhaust gas.
[0045] Step S50: Determine the lowest priority production stage among all production stages requiring tail gas reduction. Within this production stage, identify the last reduction furnace with the last accumulated reduction amount, calculate the TCS reduction of this reduction furnace, and determine the appropriate reduction amount based on the TCS reduction. The reduction rate and current reduction rate. In this step, the reduction furnace that accumulates the reduction rate last in the lowest priority production stage may have a smaller tail gas reduction rate than its existing reduction rate, therefore, its TCS reduction rate needs to be adjusted. The descent rate and current descent rate need to be recalculated.
[0046] Among them, the final TCS amount of the reduction furnace in each production stage, The final quantity and the final current quantity are respectively greater than the TCS baseline quantity of the reduction furnace. Basic quantities and current basic quantities.
[0047] In this embodiment, based on the operation of different reduction furnaces, all reduction furnaces are divided into multiple production stages. Then, the impact of the products in the reduction furnaces at different stages on TCS is determined. And the minimum current requirement, and then based on the determined TCS baseline quantity, The baseline quantity and current baseline quantity are used to determine the TCS reduction that can be achieved in each reduction furnace during each production stage. The reduction rate and current reduction rate are calculated, and the amount of tail gas that can be reduced in the reduction furnace during this production stage is set as the reduction rate.
[0048] Then, following a specific order, all individual reduction amounts are accumulated sequentially. When the sum of the accumulated individual reduction amounts is greater than or equal to the total reduction amount, the production stage of the last accumulated individual reduction amount is determined, and the TCS reduction amount of that production stage is calculated. The decrease in quantity and the decrease in current.
[0049] This technical solution can rapidly reduce exhaust gas emissions while ensuring the safety of the products in each reduction furnace, thus meeting both production and emergency needs.
[0050] In one specific embodiment:
[0051] In step S10 above, the working state of all reduction furnaces is divided into multiple production stages, including at least the initial stage, the intermediate stage, and the final stage. The initial stage and the final stage correspond to the first and last production stages, respectively. All production stages between the first and last production stages are summarized as the intermediate stage. Therefore, the intermediate stage can include several production stages.
[0052] Among them, the highest priority is given to reducing emissions in the final stage, followed by the initial stage, and then the middle stage.
[0053] In this embodiment, the polysilicon production inside the reduction furnace at the final stage is basically complete. Therefore, reducing the TCS at the final stage... The current has the least impact on the polysilicon products in the reduction furnace. When only the tail gas of the reduction furnace is reduced in the final stage, the reduction furnaces in the initial and middle stages can continue production.
[0054] When the amount of exhaust gas from the final reduction furnace is insufficient, the exhaust gas from the initial reduction furnace is then sequentially reduced. This is because the polysilicon in the initial reduction furnace is still in its early growth stage, and this process reduces its TCS (Total Chromium Sequence Size). It won't have a significant impact on the current.
[0055] When the amount of tail gas reduced in the reduction furnace at the end and beginning stages is insufficient, tail gas reduction is then applied to the reduction furnace in the middle stage. Furthermore, after tail gas reduction in the reduction furnace, the final TCS amount... The final quantity and the final current quantity are respectively greater than the TCS baseline quantity of the reduction furnace. The basic quantity and current basic quantity are used to ensure the basic growth requirements of polycrystalline silicon in the reduction furnace.
[0056] In another specific embodiment:
[0057] The above-mentioned tail gas reduction operation in the initial and final stages of the reduction furnace can reduce the final TCS amount to 0, thereby stopping the growth of polysilicon in the initial and final stages of the reduction furnace. However, it is necessary to continuously circulate gas into the initial and final stages of the reduction furnace. And a current is continuously applied, therefore, Both the final quantity and the final current quantity are not zero, and the current continues to flow. This ensures that no other gas enters the reduction furnace, and the continuous application of current ensures that the temperature inside the reduction furnace is maintained at the level required for continued production, preventing shutdown.
[0058] In another specific embodiment:
[0059] In step S10 described above, the different production stages of the reduction furnace are divided according to the different working time periods of the reduction furnace. For example, 0h-20h is divided into the initial stage, 20h-60h into the middle stage, and 60h-100h into the final stage.
[0060] Generally speaking, when the TCS in the reduction furnace, When both current and energy are in normal supply, the above-mentioned method of dividing production stages into time stages can perfectly meet the needs of this technical solution.
[0061] In another specific embodiment:
[0062] When reducing the tail gas of reduction furnaces in the final stage, all reduction furnaces in the final stage are sorted by their operating time, and the tail gas reduction operation is carried out in descending order of operating time. If the production stage is divided according to the aforementioned method, the tail gas is reduced first for reduction furnaces in the final stage with an operating time close to 100 hours, and then the tail gas is reduced sequentially for reduction furnaces with an operating time close to 60 hours.
[0063] This scheme ensures that when reducing exhaust gas in the final stage of reduction furnaces, the furnace with the longest operating time is prioritized for reduction. This results in the polysilicon growth state being optimal in the furnace with the priority exhaust gas reduction, while the polysilicon in other reduction furnaces can continue to grow. Even if a reduction furnace unexpectedly shuts down, the polysilicon inside can still be guaranteed to be in a usable state.
[0064] In another specific embodiment:
[0065] When reducing tail gas in reduction furnaces in the initial stage, all reduction furnaces in the initial stage are sorted by their operating time, and tail gas reduction is carried out in order from shortest to longest operating time. If the production stage is divided according to the aforementioned time method, tail gas reduction is carried out first for reduction furnaces in the initial stage with an operating time close to 0 hours, and then tail gas reduction is carried out sequentially for reduction furnaces with an operating time close to 20 hours.
[0066] This scheme ensures that when reducing exhaust gas in the initial stage of reduction furnaces, the furnace with the shortest operating time is prioritized for reduction. This means that the polysilicon in the furnace with the priority exhaust gas reduction has just begun to grow or has not yet started growing, while the polysilicon in other reduction furnaces can continue to grow. Even if a reduction furnace unexpectedly shuts down, it can still ensure that the polysilicon inside it can continue to grow, while the polysilicon growing in the shut-down reduction furnace is very little or even non-existent, thus minimizing losses.
[0067] In another specific embodiment:
[0068] The TCS reduction is equal to the difference between the current TCS value and the baseline TCS value. The reduction in TCS volume is equal to the product of the reduction in TCS volume and the raw material ratio, where the raw material ratio is... The ratio of the current quantity to the current quantity of TCS.
[0069] When present in a reduction furnace during one of the production stages: Current quantity - Decrease ≥ The base quantity indicates that the sum of all the individual decreases is greater than or equal to the total decrease.
[0070] The current drop is equal to the stated The product of the reduction in quantity and the power ratio.
[0071] Based on this calculation formula, the reduction in reduction exhaust gas in each production stage can be calculated directly.
[0072] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.
Claims
1. A method for controlling the amount of polycrystalline silicon reduction tail gas, characterized in that, include: Step S10: Based on the production status of polysilicon in the reduction furnace, the operation of the reduction furnace is divided into multiple production stages. Step S20: Set the basic TCS quantity required for the reduction furnace in different production stages. Basic quantities and current basic quantities, and based on TCS basic quantities, The basic quantity and current basic quantity are used to calculate the reducible tail gas volume of the reduction furnace in all production stages. This reducible tail gas volume is the fractional reduction volume. Step S30: Set the priority for reducing tail gas in reduction furnaces at different production stages; Step S40: Determine the total reduction of the reduction tail gas. According to the priority order of tail gas reduction in step S30, the reduction of the reduction furnace in different production stages is accumulated sequentially until the sum of all reductions is greater than or equal to the total reduction, at which point the accumulation stops. Step S50: Determine the lowest priority production stage among all production stages requiring tail gas reduction. Within this production stage, identify the last reduction furnace with the last accumulated reduction amount, calculate the TCS reduction of this reduction furnace, and determine the appropriate reduction amount based on the TCS reduction. Dropout and current dropout; Among them, the final TCS amount of the reduction furnace in each production stage, The final quantity and the final current quantity are respectively greater than the TCS baseline quantity of the reduction furnace. Basic quantities and current basic quantities.
2. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 1, characterized in that, In step S10, the operation of the reduction furnace includes at least three production stages: initial stage, intermediate stage, and final stage. The priority of tail gas reduction in the final stage is higher than that in the initial stage, and the priority of tail gas reduction in the initial stage is higher than that in the intermediate stage.
3. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 2, characterized in that, The baseline TCS final value can be 0 in both the initial and final stages, while the baseline TCS final value in the intermediate stage is greater than 0.
4. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 2, characterized in that, In step S10, the different production stages of the reduction furnace are divided according to the different working time periods of the reduction furnace.
5. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 4, characterized in that, When reducing the tail gas of the reduction furnace in the final stage, all reduction furnaces in the final stage are sorted by their working time, and the tail gas reduction operation is carried out in order from longest to shortest working time.
6. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 4, characterized in that, When reducing the tail gas of the reduction furnace in the initial stage, all reduction furnaces in the initial stage are sorted according to their working time, and the tail gas reduction operation is carried out in order from shortest to longest working time.
7. The method for controlling the amount of polycrystalline silicon reduction tail gas according to any one of claims 1-6, characterized in that, The TCS reduction is equal to the difference between the current TCS value and the base TCS value.
8. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 7, characterized in that, The The reduction is equal to the product of the TCS reduction and the raw material ratio, wherein the raw material ratio is: The ratio of the current quantity to the current quantity of the TCS.
9. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 8, characterized in that, When present in a reduction furnace during one of the production stages: Current quantity - Decrease ≥ The base quantity indicates that the sum of all the individual decreases is greater than or equal to the total decrease.
10. The method for controlling the amount of polycrystalline silicon reduction tail gas according to claim 7, characterized in that, The current drop is equal to the The product of the reduction in quantity and the power ratio.