Purification control method of ethyl silicate

Abstract

The invention relates to the technical field of solvent purification, and discloses a purification control method of ethyl silicate and provides a purification device.The purification control method comprises the steps that operation parameters of all rectifying towers are detected respectively, and the operation parameters comprise the reflux ratio, the tower top temperature, the tower bottom temperature and the pressure in the towers; taking the rectifying tower with the maximum deviation degree as a main control rectifying tower, and respectively defining other rectifying towers as static rectifying towers, dynamic rectifying towers or condition triggering rectifying towers according to the relative positions of the other rectifying towers and the main control rectifying tower and a preset contrast relationship; when the controlled parameters of the active rectifying tower are adjusted, the operation parameters of the other rectifying towers are detected synchronously, the static rectifying tower is adjusted according to a preset static adjusting strategy, and the static adjusting strategy, the dynamic adjusting strategy and the condition triggering adjusting strategy are executed repeatedly till the parameters and all levels of rectifying towers meet the preset operation parameters.

Description

Technical Field

[0001] The invention relates to the technical field of solvent purification, and in particular to a purification control method for ethyl silicate. Background Art

[0002] Ethyl orthosilicate (TEOS), also known as ethyl orthosilicate and tetraethoxysilane, has a chemical formula of Si(OC2H5)4. Ethyl orthosilicate is a colorless liquid with a pungent odor. The relative density is 0.933g / ml (20℃), the melting point is -77℃, the boiling point is 168℃, and the flash point is 51.67℃. Electronic Grade Tetraethyl Orthosilicate is a high-end chemical for microelectronics, a third-generation semiconductor material and an emerging semiconductor. Electronic Grade TEOS is widely used in chemical vapor deposition processes to form silicon dioxide deposition films to prevent pollutants and impurities from entering semiconductor components. At the same time, it can produce conductive layers or insulating layers, produce anti-reflection films to increase absorbance, temporarily block etching, etc. It is an electronic chemical required for the manufacture of semiconductors, discrete devices, and micro-electromechanical systems (MEMS). Electronic grade ethyl orthosilicate has extremely high quality requirements. Except for boron, the content of all other impurities must be less than 1ng / g, especially metal ion impurities (Na, K, Mg, Fe, Ca, Al, etc.). Metal ions are electrically active impurities that will reduce the insulation performance of the silicon dioxide film layer deposited on semiconductor devices, causing micron-level circuits to be interconnected, thereby causing the circuit board to be short-circuited and scrapped. Non-electrically active impurities, such as moisture and organic matter, will affect the uniformity and flatness of the deposited film layer, which is directly related to the quality of the finished product. Therefore, the development of an efficient purification process is of vital importance to improving the quality and application value of ethyl silicate.

[0003] Domestic industrial-grade ethyl orthosilicate products have been localized, but electronic-grade products have not yet been replaced by domestic products, and market demand depends on imports. The domestic semiconductor industry and the rapidly developing electronic information industry are expected to further promote the demand for electronic-grade ethyl orthosilicate, and electronic-grade ethyl orthosilicate has great research value in the market. Electronic-grade ethyl orthosilicate has extremely high quality requirements, and the purity of the components must reach 8N or more. Except for boron, the content of all other impurities must be less than 1ng / g, especially metal ion impurities (Na, K, Mg, Fe, Ca, Al, etc.). Metal ions are electrically active impurities that will reduce the insulation performance of the silicon dioxide film layer deposited on semiconductor devices, causing micron-level circuits to be interconnected, thereby causing the circuit board to be short-circuited and scrapped. Non-electrically active impurities, such as moisture and organic matter, will affect the uniformity and flatness of the deposited film layer, which is directly related to the quality of the finished product. The current methods for preparing electronic-grade ethyl orthosilicate that can be used in the semiconductor industry using industrial-grade ethyl orthosilicate as raw material include complex separation, adsorption and ion exchange, combined refining and other technologies.

[0004] The existing invention patent with the publication number of "CN114920767B" discloses a production system and process of high-purity ethyl orthosilicate. Through a multi-stage series-connected distillation device, the temperature and pressure in the distillation device are gradually reduced, and the first distillation tower is fed with nitrogen pressurized feeding, and the second, third, and fourth distillation towers are fed by the pressure difference between towers, which reduces the moving equipment in the entire production system and greatly reduces the possibility of material contamination and the maintenance of equipment. However, in the above-mentioned production system, due to the addition of multiple distillation towers, multiple control variables are introduced in the production process. Therefore, when the production starts, when the parameters of one of the distillation towers are adjusted, the operating parameters of other distillation towers will also be affected, and it takes a long time to adjust, causing the performance of the output product to fluctuate. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a purification control method for ethyl silicate.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A purification control method for ethyl silicate, providing a purification device, the purification device comprising four-stage series-arranged distillation towers, each stage of the distillation towers is provided with a condenser at the top, each stage of the distillation towers is provided with a reboiler at the bottom, the temperature and pressure in each distillation tower are reduced step by step, each of the distillation towers is provided with a tower top temperature sensor, a tower bottom temperature sensor and a pressure sensor, the purification control method comprises

[0008] The operating parameters of each distillation tower are tested respectively, including the reflux ratio, tower top temperature, tower bottom temperature and tower pressure, and the distillation tower with the largest deviation is used as the main control distillation tower.

[0009] According to the relative positions of the remaining distillation towers and the main control distillation tower, and according to the preset control relationship, the remaining distillation towers are defined as static distillation towers, dynamic distillation towers or condition-triggered distillation towers;

[0010] When the controlled parameters of the active distillation tower are adjusted, the operating parameters of the remaining distillation towers are detected synchronously, the static distillation tower is adjusted according to the preset static adjustment strategy, the controlled parameters of the dynamic distillation tower are adjusted according to the preset dynamic adjustment strategy or the preset static adjustment strategy, the priority of the dynamic adjustment strategy is higher than the priority of the static adjustment strategy, the conditional trigger distillation tower is adjusted according to the preset conditional trigger strategy or the preset static adjustment strategy, the priority of the conditional trigger strategy is higher than the static adjustment strategy, the static adjustment strategy, the dynamic adjustment strategy and the conditional trigger adjustment strategy are repeatedly executed until the parameters of the distillation towers at each level meet the preset operating parameters.

[0011] Furthermore, the expression of the static adjustment strategy is:

[0012] ΔP reboiler =K p ·(a·∈ T +b·∈ Tbottom +c·∈ P );

[0013] ΔP condenser =K p ·(-d·∈ R );

[0014] Among them, ΔP reboiler Indicates the adjustment amount of the reboiler operating power, ΔP condenser Indicates the adjustment amount of the condenser operating power, K p represents the proportional gain coefficient, ∈ T Indicates the error between the actual measured tower top temperature and the preset tower top temperature, ∈ Tbottom Represents the error between the actual measured tower bottom temperature and the preset tower bottom temperature, ∈ P Indicates the error value between the actual measured tower pressure and the preset tower pressure.

[0015] Furthermore, the dynamic adjustment strategy is configured with several influencing factors, including the relative position between the current distillation tower and the main control distillation tower, the operation time of the current distillation tower, the number of adjustments of the current distillation tower,

[0016] The calculation formula of the dynamic adjustment strategy includes:

[0017]

[0018] Among them, ΔP represents the adjustment amplitude, K represents the basic adjustment coefficient, T dev Indicates temperature deviation, P dev It represents the pressure deviation. f(t) is a function related to the running time. It increases with time and is used to slow down the adjustment speed. g(n) is a function related to the number of adjustments. It decreases with the increase of the number of adjustments and is used to limit the adjustment frequency. ΔP adjacent It represents the difference of parameters before and after the distillation tower, and h is the correction coefficient of the difference of parameters before and after the distillation tower.

[0019] Further, the first trigger condition is configured with a preset pressure change rate threshold. The first trigger condition is specifically that the measured pressure change rate inside the main control distillation tower is detected to exceed the preset pressure change rate threshold. The expression of the first trigger sub-strategy is:

[0020]

[0021] P′ condenser =P condenser -q2*(ΔP / Δt-ΔP t / Δt)*P condenser ;

[0022] Among them, P reboller Represents the operating power of the reboiler, P condenser Indicates the operating power of the condenser, P′ reboiler represents the operating power of the reboiler after adjustment, P′ condenser represents the operating power of the condenser after adjustment, ΔP represents the pressure change in the main control distillation tower within the period of Δt, ΔP t / Δt represents the pressure change rate threshold, q1 represents the adjustment factor of the reboiler, and q2 represents the reboiler factor of the condenser.

[0023] Furthermore, the second trigger condition is specifically that when the operating power of the reboiler or condenser of the main control distillation tower is adjusted to an extreme value, its operating parameters cannot be adjusted to the corresponding preset operating range, and the second trigger sub-strategy is specifically to reduce the condition to trigger the preset operating parameter range of the corresponding operating parameter of the distillation tower.

[0024] Furthermore, the purification control method is configured with an abnormal regulation strategy. When it is detected that the operating power of the reboiler or condenser corresponding to a certain stage of the distillation tower is adjusted to an extreme value, and the operating parameters of the distillation tower of this stage have not yet been adjusted to a preset operating range, the operating parameters of the previous stage of the distillation tower are re-adjusted and then the operating parameters of the distillation tower of this stage are repeatedly adjusted to meet the preset operating range.

[0025] Further, the purification control method is configured with a first parameter correction strategy, which includes repeatedly calculating the top temperature error value, the bottom temperature error value and the pressure error value after executing the static adjustment strategy. The top temperature error value represents the error value between the actually measured tower top temperature and the preset tower top temperature. The bottom temperature error value represents the error value between the actually measured tower bottom temperature and the preset tower bottom temperature. The pressure error value represents the error value between the actually measured tower pressure and the preset tower pressure. If the top temperature error value still exists, the proportional coefficient a corresponding to the top temperature error is increased. If the bottom temperature error value still exists, the proportional coefficient b corresponding to the top and bottom errors is increased. If the pressure error value still exists, the proportional coefficient c corresponding to the pressure error is increased.

[0026] Beneficial effects of the present invention:

[0027] The present invention defines a multi-stage distillation tower, takes the distillation tower with the largest deviation as the main control distillation tower, uses multiple distillation towers for joint adjustment, and provides a dynamic adjustment strategy, a static adjustment strategy and a condition-triggered adjustment strategy, so that the distillation towers at each stage can be adjusted to a stable state more quickly, and the repeated adjustment process between the multiple distillation towers is reduced, and the safety of the multiple distillation towers in the adjustment process is taken into account, thereby reducing the adjustment time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the purification device in the present invention;

[0029] Figure 2 It is a flow chart of the control method of the present invention.

[0030] Figure numerals: 1, primary distillation tower; 11, primary reboiler; 12, primary condenser; 2, secondary distillation tower; 21, secondary reboiler; 22, secondary condenser; 3, tertiary distillation tower; 31, tertiary reboiler; 32, tertiary condenser; 4, quaternary distillation tower; 41, quaternary reboiler; 42, quaternary condenser. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0034] A purification control method for ethyl silicate of the present embodiment provides a purification device, wherein the purification device includes four stages of distillation towers arranged in series, a condenser is arranged at the top of each stage of the distillation tower, a reboiler is arranged at the bottom of each stage of the distillation tower, the temperature and pressure in each distillation tower are reduced step by step, and each of the distillation towers is provided with a tower top temperature sensor, a tower bottom temperature sensor and a pressure sensor.

[0035] like Figure 1 As shown, the crude ethyl silicate is sequentially transported to the primary distillation tower 1 by the pressure pushing effect of nitrogen;

[0036] The top steam of the primary distillation tower 1 is discharged as light component impurities, and part of it is refluxed into the primary distillation tower 1 after heat exchange in the primary condenser 12; a primary reboiler 11 is arranged at the bottom of the primary distillation tower 1, and the crude ethyl silicate after the first light distillation enters the secondary distillation tower 2 through the bottom of the primary distillation tower 1 through the pressure difference between towers;

[0037] Part of the overhead steam of the secondary distillation tower 2 flows back to the secondary distillation tower 2 for further distillation after passing through the secondary condenser 22, and part of it enters the tertiary distillation tower 3 through the pressure difference between towers; a secondary reboiler 21 is provided at the bottom of the secondary distillation tower 1, and heavy impurities are discharged from the bottom of the secondary distillation tower 2;

[0038] After the crude ethyl silicate product undergoes secondary de-heavy distillation, it enters the three-stage distillation tower 3, and part of the tower top steam is discharged as light component impurities, and part of the tower top steam passes through the three-stage condenser 32 and refluxes to the three-stage distillation tower 4 for further distillation; a three-stage reboiler 31 is provided at the bottom of the three-stage distillation tower 3, and the heavy components at the bottom of the tower enter the four-stage distillation tower 4 through the pressure difference between towers;

[0039] After three times of light de-distillation, the crude ethyl silicate enters the four-stage distillation tower 4, part of the top steam is refluxed to the four-stage distillation tower T04 through the four-stage condenser 42 for further distillation, and part of it is extracted as a high-purity ethyl silicate product; a four-stage reboiler 41 is provided at the bottom of the four-stage distillation tower 4, and heavy impurities are discharged from the bottom of the four-stage distillation tower 4.

[0040] The purification control method comprises

[0041] The operating parameters of each distillation tower are tested respectively, including the reflux ratio, tower top temperature, tower bottom temperature and tower pressure, and the distillation tower with the largest deviation is used as the main control distillation tower.

[0042] According to the relative positions of the remaining distillation towers and the main control distillation tower, and according to the preset control relationship, the remaining distillation towers are defined as static distillation towers, dynamic distillation towers or condition-triggered distillation towers;

[0043] When the controlled parameters of the active distillation tower are adjusted, the operating parameters of the remaining distillation towers are detected synchronously, the static distillation tower is adjusted according to the preset static adjustment strategy, the controlled parameters of the dynamic distillation tower are adjusted according to the preset dynamic adjustment strategy or the preset static adjustment strategy, the priority of the dynamic adjustment strategy is higher than the priority of the static adjustment strategy, the conditional trigger distillation tower is adjusted according to the preset conditional trigger strategy or the preset static adjustment strategy, the priority of the conditional trigger strategy is higher than the static adjustment strategy, the static adjustment strategy, the dynamic adjustment strategy and the conditional trigger adjustment strategy are repeatedly executed until the parameters of the distillation towers at each level meet the preset operating parameters. For example: when the first-stage distillation tower 1 is used as the main control distillation tower, the second-stage distillation tower 2 is used as a dynamic distillation tower, the third-stage distillation tower 3 is used as a static distillation tower, and the fourth-stage distillation tower 4 is used as a static distillation tower; at this time, the parameters of the first-stage distillation tower are adjusted first, and for the control of the main control distillation tower, the conventional PID control method can be referred to, and the parameters of the active distillation tower can be adjusted to meet the preset range; for the second, third, and fourth-stage distillation towers, when the operating parameters exceed the preset range, the distillation towers at each level are adjusted according to the preset static adjustment strategy. At the same time, for the dynamic distillation tower, considering that the adjustment of the main control distillation tower has different effects on the operation of the subsequent distillation towers, there is an amplification effect of the error with the increasing number of stages, so in order to reduce the superposition of errors, a dynamic distillation tower is set. For example, if the reflux ratio of the first-stage distillation tower is increased and the discharge of the first-stage distillation tower is reduced, the feed amount of the second-stage distillation tower will be reduced. Accordingly, the reflux ratio of the second-stage distillation tower should be lowered to reduce the impact on the inside of the tertiary and quaternary distillation towers. For conditionally triggered distillation towers, the functions of conditionally triggered distillation include maintaining stability and ensuring safety.

[0044] Another example: when the secondary distillation tower is used as the main control distillation tower, the tertiary distillation tower is used as the dynamic distillation tower, the quaternary distillation tower is used as the static distillation tower, and the primary distillation tower is used as the conditional trigger distillation tower;

[0045] The expression of the static adjustment strategy is:

[0046] ΔP reboiler =K p ·(a·∈ T +b·∈ Tbottom +c·∈ P );

[0047] ΔP condenser =K p ·(-d·∈ R );

[0048] Among them, ΔP reboiler Indicates the adjustment amount of the reboiler operating power, ΔP condenser Indicates the adjustment amount of the condenser operating power, K prepresents the proportional gain coefficient, ∈ T Indicates the error between the actual measured tower top temperature and the preset tower top temperature, ∈ Tbottom Represents the error between the actual measured tower bottom temperature and the preset tower bottom temperature, ∈ P Indicates the error value between the actual measured tower pressure and the preset tower pressure.

[0049] The dynamic adjustment strategy is configured with several influencing factors, including the relative position between the current distillation tower and the main control distillation tower, the operation time of the current distillation tower, the number of adjustments of the current distillation tower,

[0050] The calculation formula of the dynamic adjustment strategy includes:

[0051]

[0052] Among them, ΔP represents the adjustment amplitude, K represents the basic adjustment coefficient, T dev Indicates temperature deviation, P dev It represents the pressure deviation. f(t) is a function related to the running time. It increases with time and is used to slow down the adjustment speed. g(n) is a function related to the number of adjustments. It decreases with the increase of the number of adjustments and is used to limit the adjustment frequency. ΔP adjacent It represents the difference of parameters before and after the distillation tower, and h is the correction coefficient of the difference of parameters before and after the distillation tower.

[0053] The current setting of the operating time of the distillation tower is based on the fact that as the operating time increases, the stability of the distillation tower may decrease, so more frequent or larger adjustments are required. A coefficient proportional to the operating time can be introduced to adjust the sensitivity of the adjustment strategy; the current setting of the number of adjustments of the distillation tower is based on the fact that frequent adjustments may lead to system instability, so the frequency and amplitude of the adjustments should be limited. A coefficient inversely proportional to the number of adjustments can be introduced to slow down the adjustment speed or reduce the adjustment amplitude; the current setting of the temperature deviation of the distillation tower is based on the fact that when the temperature deviation is large, more active adjustments are required to quickly restore the stable state. The temperature deviation can be used as a direct factor of the adjustment amplitude. The larger the deviation, the more active the adjustment; the current setting of the pressure deviation of the distillation tower is based on the fact that the pressure deviation also affects the distillation effect and needs to be adjusted accordingly. Similar to the temperature deviation, the pressure deviation can be included in the calculation of the adjustment amplitude; the setting of the comparison of the operating parameters of the front and rear distillation towers is based on the fact that if the parameters of the front and rear distillation towers are significantly different, more cautious adjustments may be required to avoid chain reactions. A correction coefficient based on the difference in parameters of the front and rear distillation towers can be introduced to balance the aggressiveness of the adjustment.

[0054] The first trigger condition is configured with a preset pressure change rate threshold. The first trigger condition is specifically that the measured pressure change rate inside the main control distillation tower is detected to exceed the preset pressure change rate threshold. The expression of the first trigger sub-strategy is:

[0055]

[0056] P′ condenser =P condenser -q2*(ΔP / Δt-ΔP t / Δt)*P condenser ;

[0057] Among them, P reboiler Represents the operating power of the reboiler, P condenser Indicates the operating power of the condenser, P r ' eboiler Represents the operating power of the reboiler after adjustment, P c ' ondenser represents the operating power of the condenser after adjustment, ΔP represents the pressure change in the main control distillation tower within the period of Δt, ΔP t / Δt represents the pressure change rate threshold, q1 represents the reboiler adjustment factor, and q2 represents the condenser reboiler factor. When the measured pressure change rate inside the main control distillation tower exceeds the preset threshold, it indicates that the system may have too fast pressure changes, which may cause equipment damage or unstable operation. By increasing the power of the reboiler (P' reboiler ) and reduce the condenser power (P' condenser ), the reflux ratio of the condition-triggered distillation tower can be increased, thereby slowing down the pressure change rate inside the main distillation tower; the adjustment factor k is used to quantify the impact of the pressure change rate on the reboiler and condenser power when the pressure change rate exceeds the threshold, ensuring that the adjustment is gradual and avoiding new unstable factors caused by over-adjustment.

[0058] Furthermore, the second trigger condition is specifically that when the operating power of the reboiler or condenser of the main control distillation tower is adjusted to an extreme value, its operating parameters cannot be adjusted to the corresponding preset operating range, and the second trigger sub-strategy is specifically to reduce the condition to trigger the preset operating parameter range of the corresponding operating parameter of the distillation tower.

[0059] Furthermore, the purification control method is configured with an abnormal regulation strategy. When it is detected that the operating power of the reboiler or condenser corresponding to a certain stage of the distillation tower is adjusted to an extreme value, and the operating parameters of the distillation tower of this stage have not yet been adjusted to a preset operating range, the operating parameters of the previous stage of the distillation tower are re-adjusted and then the operating parameters of the distillation tower of this stage are repeatedly adjusted to meet the preset operating range.

[0060] Further, the purification control method is configured with a first parameter correction strategy, which includes repeatedly calculating the top temperature error value, the bottom temperature error value and the pressure error value after executing the static adjustment strategy. The top temperature error value represents the error value between the actually measured tower top temperature and the preset tower top temperature. The bottom temperature error value represents the error value between the actually measured tower bottom temperature and the preset tower bottom temperature. The pressure error value represents the error value between the actually measured tower pressure and the preset tower pressure. If the top temperature error value still exists, the proportional coefficient a corresponding to the top temperature error is increased. If the bottom temperature error value still exists, the proportional coefficient b corresponding to the top and bottom errors is increased. If the pressure error value still exists, the proportional coefficient c corresponding to the pressure error is increased.

[0061] Working principle:

[0062] 1. Pretreatment: Preliminary filtration of industrial grade ethyl silicate raw materials to remove suspended solid impurities.

[0063] 2. Distillation: Use a multi-stage distillation tower to distill the pretreated ethyl silicate. During the distillation process, by controlling the temperature, pressure and reflux ratio at the top and bottom of the tower, the temperature and pressure in the distillation device are gradually reduced to achieve efficient separation and purification of ethyl silicate.

[0064] 3. Drying: Dry the distilled ethyl silicate to remove the water therein. Molecular sieves, anhydrous magnesium sulfate and other desiccants can be used for drying.

[0065] 4. Filtration: Filter the dried ethyl silicate to remove any tiny solid impurities that may exist.

[0066] 5. Removal of boron impurities: The filtered ethyl silicate is passed through a boron adsorption resin to remove boron impurities.

[0067] 6. Anion and cation removal: removal of anions and / or cations in ethyl silicate

[0068] 7. Quality testing: Conduct quality testing on the purified ethyl silicate to ensure that its purity and quality meet the predetermined standards.

[0069] Through the above steps, high-purity ethyl silicate products can be obtained to meet the needs of high-end application fields.

[0070] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A purification control method for ethyl silicate, characterized in that: A purification device is provided, the purification device comprising four-stage distillation towers arranged in series, a condenser is arranged at the top of each distillation tower, a reboiler is arranged at the bottom of each distillation tower, the temperature and pressure in each distillation tower are reduced step by step, each distillation tower is provided with a tower top temperature sensor, a tower bottom temperature sensor and a pressure sensor, and the purification control method comprises The operating parameters of each distillation tower are tested respectively, including the reflux ratio, tower top temperature, tower bottom temperature and tower pressure, and the distillation tower with the largest deviation is used as the main control distillation tower. According to the relative positions of the remaining distillation towers and the main control distillation tower, and according to the preset control relationship, the remaining distillation towers are defined as static distillation towers, dynamic distillation towers or condition-triggered distillation towers; When the controlled parameters of the active distillation tower are adjusted, the operating parameters of the remaining distillation towers are detected synchronously, the static distillation tower is adjusted according to the preset static adjustment strategy, the controlled parameters of the dynamic distillation tower are adjusted according to the preset dynamic adjustment strategy or the preset static adjustment strategy, the priority of the dynamic adjustment strategy is higher than the priority of the static adjustment strategy, the conditional trigger distillation tower is adjusted according to the preset conditional trigger strategy or the preset static adjustment strategy, the priority of the conditional trigger strategy is higher than the static adjustment strategy, the static adjustment strategy, the dynamic adjustment strategy and the conditional trigger adjustment strategy are repeatedly executed until the parameters of the distillation towers at each level meet the preset operating parameters.

2. The method for controlling the purification of ethyl silicate according to claim 1, characterized in that: The expression of the static adjustment strategy is: ΔP reboiler =K p ·(a·∈ T +b·∈ Tbottom +c·∈ P ); ΔP condenser =K p ·(-d·∈ R ); Where ΔP reboiler Indicates the adjustment amount of the reboiler operating power, ΔP condenser Indicates the adjustment amount of the condenser operating power, K p represents the proportional gain coefficient, ∈ T It represents the error between the actual measured tower top temperature and the preset tower top temperature, a represents ∈ T The proportionality coefficient, ∈ Tbottom It represents the error between the actual measured tower bottom temperature and the preset tower bottom temperature, b represents ∈ Tbottom The proportionality coefficient, ∈ P It indicates the error between the actual measured pressure in the tower and the preset pressure in the tower, c indicates ∈ P The proportionality coefficient, d represents ∈ R The proportionality factor.

3. The purification control method of ethyl silicate according to claim 1, characterized in that: The dynamic adjustment strategy is configured with several influencing factors, including the relative position between the current distillation tower and the main control distillation tower, the operation time of the current distillation tower, the number of adjustments of the current distillation tower, The calculation formula of the dynamic adjustment strategy includes: Among them, ΔP represents the adjustment amplitude, K represents the basic adjustment coefficient, T dev Indicates temperature deviation, P dev It represents the pressure deviation. f(t) is a function related to the running time. It increases with time and is used to slow down the adjustment speed. g(n) is a function related to the number of adjustments. It decreases with the increase of the number of adjustments and is used to limit the adjustment frequency. ΔP adjacent It represents the difference of parameters before and after the distillation tower, and h is the correction coefficient of the difference of parameters before and after the distillation tower.

4. The purification control method of ethyl silicate according to claim 1, characterized in that: The conditional trigger adjustment strategy is configured with a preset first trigger condition, a second trigger condition, and a preset first trigger sub-strategy and a preset second trigger sub-strategy. When the first trigger condition is met, the operating parameters of the conditionally triggered distillation tower are adjusted according to the preset first trigger sub-strategy. When the second trigger condition is met, the operating parameters of the conditionally triggered distillation tower are adjusted according to the preset second trigger sub-strategy.

5. The purification control method of ethyl silicate according to claim 4, characterized in that: The first trigger condition is configured with a preset pressure change rate threshold. The first trigger condition is specifically that the measured pressure change rate inside the main control distillation tower is detected to exceed the preset pressure change rate threshold. The expression of the first trigger sub-strategy is: P′ condenser =P condenser -q2*(ΔP / Δt-ΔP t / Δt)*P condenser ; Among them, P reboiler Represents the operating power of the reboiler, P condenser Indicates the operating power of the condenser, P′ reboiler represents the operating power of the reboiler after adjustment, P′ condenser represents the operating power of the condenser after adjustment, ΔP represents the pressure change in the main control distillation tower within the period of Δt, ΔP t / Δt represents the pressure change rate threshold, q1 represents the adjustment factor of the reboiler, and q2 represents the reboiler factor of the condenser.

6. The method for controlling the purification of ethyl silicate according to claim 4, characterized in that: The second trigger condition is specifically that when the operating power of the reboiler or condenser of the main control distillation tower is adjusted to the extreme value, its operating parameters cannot be adjusted to the corresponding preset operating range. The second trigger sub-strategy is specifically to reduce the condition to trigger the preset operating parameter range of the corresponding operating parameter of the distillation tower.

7. The purification control method of ethyl silicate according to claim 1, characterized in that: The purification control method is configured with an abnormal regulation strategy. When it is detected that the operating power of the reboiler or condenser corresponding to a certain stage of the distillation tower is adjusted to an extreme value, and the operating parameters of the distillation tower of this stage have not yet been adjusted to a preset operating range, the operating parameters of the distillation tower of the previous stage are re-adjusted and then the operating parameters of the distillation tower of this stage are repeatedly adjusted to meet the preset operating range.

8. The method for controlling the purification of ethyl silicate according to claim 2, characterized in that: The purification control method is configured with a first parameter correction strategy, which includes repeatedly calculating the top temperature error value, the bottom temperature error value and the pressure error value after executing the static adjustment strategy. The top temperature error value represents the error value between the actual measured tower top temperature and the preset tower top temperature, the bottom temperature error value represents the error value between the actual measured tower bottom temperature and the preset tower bottom temperature, and the pressure error value represents the error value between the actual measured tower pressure and the preset tower pressure. If the top temperature error value still exists, the proportional coefficient a corresponding to the top temperature error is increased; if the bottom temperature error value still exists, the proportional coefficient b corresponding to the top and bottom errors is increased; if the pressure error value still exists, the proportional coefficient c corresponding to the pressure error is increased.

Images