Etching wastewater treatment method based on multi-source data fusion

Abstract

The present application relates to wastewater treatment technical field, especially to a kind of etching wastewater treatment method based on multi-source data fusion, the method includes: adjusting pipe network valve to collect waste liquid;Determine pipe heat tracing parameter;Determine wastewater treatment strategy;Determine equipment operation mode and the dosing parameter of acidic reagent and execute acid-base fine adjustment.The present application carries out acid-base shunting by signal mapping;Then utilize multi-source physical property parameter quantification supersaturation to prevent blockage with dynamic heat tracing;After waste liquid safely enters pool, the equivalent of supply and demand is calculated to guide macroscopic scheduling, then in the scheduling process, in view of the nonlinear jump characteristics of neutralization reaction, if continuous rough dosing easily leads to pH overshoot, introduce dosing ratio threshold value smooth cut-in fine adjustment;Finally, in the end of fine adjustment, directly with the closed-loop fine adjustment of the precipitation interval of standard requirement as the benchmark, to solve the composite problem of pipe blockage and end neutralization out of control in etching wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an etching wastewater treatment method based on multi-source data fusion. Background Technology

[0002] Chemical milling for thinning aluminum alloy components and surface treatment for die casting are core technological steps. These processes sequentially employ strong alkali etching and strong acid brightening, resulting in etching wastewater with three extreme industrial properties: high concentration alternation, batch impact, and thermodynamic metastability. Current industrial practices for treating these extreme wastewaters generally suffer from process disconnect, lag in response, and crude control. There is an urgent need for a method that deeply integrates production scheduling, multi-dimensional soft measurement of physical properties, and tiered feedforward-feedback interlocking control to systematically solve the problems of gel blockage, equivalent distortion, and precipitation re-dissolution in aluminum alloy etching wastewater treatment.

[0003] Chinese Patent Application Publication No. CN107777765A discloses a method and system for neutralizing and discharging acid and alkali wastewater from a nuclear power plant. The method includes: recording parameters for neutralizing acid and alkali wastewater in a neutralization container under different operating conditions: optimal number of acid and alkali additions, optimal stirring time, and pH measurement delay time; determining the functional relationship between the liquid level and volume of the neutralization container based on its geometric dimensions; mixing the acid and alkali wastewater in the neutralization container and collecting its liquid level and pH data; calculating the optimal acid and alkali addition amount using a mathematical model based on the recorded parameters, the determined functional relationship, and the collected data; and adding chemicals according to the optimal acid and alkali addition amount to complete the wastewater neutralization.

[0004] Therefore, the method for neutralizing and discharging acid and alkali wastewater from nuclear power plants has the following problems: First, key parameters mainly rely on operators to determine based on pH measurements and experience. This method is affected by various factors such as pH nonlinearity, mixing uniformity, and instrument lag, making it difficult to adapt to actual conditions and resulting in difficulty in automatic process control. Second, the lack of precise control makes it easy for excessive acid and alkali dosage to occur during operation, leading to repeated neutralization and greatly increasing the consumption of chemicals. Summary of the Invention

[0005] To address this, the present invention provides an etching wastewater treatment method based on multi-source data fusion, which overcomes the problems of acid-base mixing gel blockage, cooling hydrolysis pipeline crystallization, and neutralization over-flushing precipitation and re-dissolution caused by response lag in the prior art through multi-dimensional data fusion analysis and differentiated strategy execution.

[0006] To achieve the above objectives, the present invention provides a method for treating etching wastewater based on multi-source data fusion, comprising: The switching of the pipeline valve array is controlled based on the waste liquid type during the waste liquid collection process, and independent buffer tank collection is carried out. The waste liquid type is determined based on the batch discharge trigger signal and tank identification obtained in real time from the production line control system. In response to the determination that the waste liquid is a high-alkali waste liquid, the pipeline heating parameters during the process of discharging the waste liquid into the pipeline are determined based on the pipe liquid temperature difference, supersaturation and preset benchmark threshold. The supersaturation is determined based on the real-time acquired online temperature, online conductivity and online density, and the pipe liquid temperature difference is based on the real-time acquired pipeline temperature and online temperature. Wastewater treatment strategies are determined based on the comparison between available acid quantity and theoretical acid quantity, as well as the liquid level of the alkaline buffer tank. The theoretical acid quantity is determined based on the liquid level, pH, and physical properties of the waste liquid in the alkaline buffer tank, while the available acid quantity is determined based on the liquid level, physical properties of the waste liquid, and geometric parameters of the tank in the acid buffer tank. Based on the aforementioned wastewater treatment strategy, the operating mode of the waste liquid extraction equipment, the dosing rate of the acidic agent, the dosing source, and the target amount of acid to be added are determined. Whether to perform acid-base fine-tuning is determined based on the neutralization addition ratio, wherein the neutralization addition ratio is determined based on the target amount of acid added and the actual amount added during the real-time acquisition of the mixing reaction process; In response to the determination result of the acid-base fine-tuning, the fine-tuning frequency of the acid reagent dosing equipment is determined based on the deviation between the acidity and alkalinity during the mixing reaction process and the target precipitation range, which is acquired in real time.

[0007] Furthermore, the process of controlling the switching of the pipeline valve array during wastewater collection based on wastewater type, and performing independent buffer pool collection, includes: In response to the batch discharge trigger signal, the waste liquid type is determined to be either high-alkali waste liquid or high-acid waste liquid based on the tank identifier and the preset tank type table; In response to the determination that the waste liquid is of high alkalinity, the valve of the alkaline liquid diversion pipeline is opened and the valve of the acid liquid diversion pipeline is closed. In response to the determination that the waste liquid is of the high acid type, the valve of the acid diversion pipeline is opened and the valve of the alkali diversion pipeline is closed.

[0008] Furthermore, the process of determining supersaturation includes: Supersaturation is determined based on the concentration difference and equilibrium concentration values, where, The concentration difference is determined based on the actual concentration value and the equilibrium concentration value. The actual concentration value is determined based on the online temperature, the online conductivity, and the online density. The equilibrium concentration value is determined based on the online temperature and the actual concentration value.

[0009] Furthermore, the process of determining the pipeline heat tracing parameters includes: Based on the comparison results between the pipe fluid temperature difference and the preset temperature difference threshold, and the comparison results between the supersaturation and the preset supersaturation threshold, the pipe temperature is adjusted according to the pipe fluid temperature difference and the preset temperature difference threshold. The temperature difference between the liquid and the tubing is determined based on the online temperature and the tubing temperature.

[0010] Furthermore, the process of determining the amount of available acid includes: The amount of usable acid is determined based on the volume of waste acid and the effective acid concentration, wherein... The volume of waste acid is determined based on the liquid level, dead zone height, and bottom cross-sectional area of ​​the acid buffer tank, while the effective acid concentration is determined based on the waste liquid conductivity, waste liquid density, and waste liquid temperature.

[0011] Furthermore, the process of determining the theoretical acidity includes: The theoretical acid quantity is determined based on the volume of waste alkali and the actual effective alkalinity value, where, The volume of waste alkali is determined based on the liquid level, dead zone height, and bottom cross-sectional area of ​​the alkaline buffer tank. The actual effective alkalinity value is determined based on the pH of the alkaline buffer tank, the conductivity of the waste liquid, and the density of the waste liquid.

[0012] Furthermore, the process of determining a wastewater treatment strategy includes: Based on the determination result that the available acid quantity is greater than the preset minimum guaranteed acid quantity, the net available acid quantity is determined according to the available acid quantity and the preset minimum guaranteed acid quantity; Based on the determination result that the net available acid quantity is greater than or equal to the theoretical acid quantity, the wastewater treatment strategy is determined to be a full mixing strategy. Based on the determination that the net available acid quantity is less than the theoretical acid quantity and the liquid level of the alkaline buffer tank is less than the preset overflow warning height, the wastewater treatment strategy is determined to be a flow-limited batch mixing strategy. Based on the determination that the net available acid quantity is less than the theoretical acid quantity and the liquid level of the alkaline buffer tank is greater than or equal to the preset overflow warning height, the wastewater treatment strategy is determined to be a supplementary commercial acid source strategy.

[0013] Furthermore, the process of determining the operating mode of the waste liquid extraction equipment, the dosing rate of the acidic agent, the dosing source, and the target acid dosage includes: In response to the full-volume mixing strategy, the operating mode of the waste liquid extraction equipment is determined to be continuous operation mode, and the source of the acidic agent is determined to be waste acid in the acid buffer tank. The theoretical acid volume is used as the target acid dosage, and the dosing rate is determined based on the waste alkali volume and the theoretical acid volume. The theoretical acid volume is determined based on the target amount of acid added and the effective acid concentration. In response to the flow-limiting, batch-mixing strategy, the operating mode of the waste liquid extraction equipment is determined to be a quantitative operating mode. The source of the acidic agent is determined to be the waste acid in the acid buffer tank. The net available acid volume is used as the target acid dosage, and the dosing rate is determined based on the single-batch treatable waste alkali volume and the theoretical acid volume. The volume of waste alkali that can be processed in a single batch is determined based on the target amount of acid added and the actual effective alkalinity value. In response to the aforementioned supplemental commercial acid source strategy, the operating mode of the waste liquid extraction equipment is determined to be the continuous operation mode, the dosing source of the acidic agent is determined to be an externally connected commercial acid source, and the theoretical acid amount is used as the target acid dosing amount. The dosing rate is determined based on the nominal concentration of the commercial acid liquid, the target acid dosing amount, and the volume of waste alkali.

[0014] Furthermore, the process of determining whether to perform acid-base fine-tuning includes: Based on the comparison between the neutralization dosage ratio and the preset ratio threshold, it is determined whether to perform the acid-base fine-tuning, wherein... The neutralization dosage ratio is determined based on the actual dosage and the target acid dosage.

[0015] Furthermore, the process of determining the fine-tuning operating frequency of the acidic reagent dosing pump includes: The preset basic operating frequency is adjusted according to the target deviation to obtain the adjusted operating frequency, wherein the target deviation is determined based on the pH and the median value of the target precipitation range; In response to the determination result that the wastewater treatment strategy is the full-volume mixing strategy or the flow-limited batch mixing strategy, the fine-tuning operating frequency is determined to be the adjustment operating frequency. In response to the determination that the wastewater treatment strategy is the supplementary commercial acid source strategy, the fine-tuning operating frequency is determined based on the adjusted operating frequency and concentration ratio, wherein the concentration ratio is determined based on the nominal concentration of the commercial acid and the effective acid concentration.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: In the entire process of etching wastewater separation collection and neutralization treatment, since the instantaneous mixing of acid and alkali wastewater can easily induce irreversible precipitation, acid and alkali are first separated through signal mapping; then, considering the risk of hydrolysis and pipe blockage due to the interference of ambient temperature drop when high-alkali wastewater is discharged into the pipe, the supersaturation is quantified using multi-source physical property parameters for dynamic heating to prevent blockage; after the wastewater is safely discharged into the tank, due to the large fluctuations in water quality between batches, blind addition can easily lead to acid-alkali imbalance, so the supply and demand equivalent is calculated to guide macro-scheduling; in the strategy execution stage, given the nonlinear jump characteristics of the neutralization reaction, continuous extensive addition can easily lead to pH overshoot, so a addition ratio threshold is introduced to smoothly cut into fine adjustment; finally, at the end of the fine adjustment, a closed-loop fine adjustment is directly based on the precipitation range that meets the standard requirements, thereby solving the combined problem of pipeline blockage and end-neutralization failure in etching wastewater treatment. Attached Figure Description

[0017] Figure 1 This is a flowchart of the etching wastewater treatment method based on multi-source data fusion in this embodiment; Figure 2 This is a flowchart illustrating the process of collecting waste liquid from the entire pipeline network valves in this embodiment. Figure 3 A flowchart for determining the supersaturation in this embodiment; Figure 4 This is a flowchart for determining the pipeline heat tracing parameters in this embodiment. Detailed Implementation

[0018] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0019] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0020] Please see Figure 1 The diagram shown is a flowchart of the etching wastewater treatment method based on multi-source data fusion in this embodiment. The method in this embodiment includes: Step S1: Based on the waste liquid type, control the switching of the pipeline valve array during the waste liquid collection process and carry out independent buffer pool collection to complete the separate collection of waste liquid in the independent buffer pool. The waste liquid type is determined based on the batch discharge trigger signal and tank identification obtained in real time from the production line control system.

[0021] In this embodiment, the batch drainage trigger signal is generated based on the action switch quantity of the automated handling equipment or the opening switch quantity of the tank drainage valve; the tank identifier is determined based on the binding mapping between the current action source and the physical number of the tank by the production line control system.

[0022] Step S2: In response to the determination that the waste liquid is a high-alkali waste liquid, the pipeline heating parameters during the process of discharging the waste liquid into the pipeline are determined based on the pipe liquid temperature difference, supersaturation, and preset benchmark threshold, so as to suppress the formation of aluminum hydroxide gel by sodium aluminate hydrolysis induced by the drastic cooling after the waste liquid is discharged into the pipeline, which will block the pipeline. The supersaturation is determined based on the real-time online temperature, online conductivity, and online density, and the pipe liquid temperature difference is based on the real-time pipeline temperature and online temperature.

[0023] In this embodiment, the pipeline temperature is determined based on temperature sensors installed on the outer wall of the workshop drainage network; the online temperature is determined based on temperature sensors installed on the drainage source tank or the inlet of the main drainage pipe; the online conductivity is determined based on an industrial-grade conductivity meter installed on the drainage source and equipped with anti-corrosion lining and self-cleaning function; and the online density is determined based on a tuning fork-type online density meter installed on the drainage source.

[0024] In this embodiment, the preset reference threshold includes a preset temperature difference threshold and a preset supersaturation threshold.

[0025] Step S3: Determine the wastewater treatment strategy based on the comparison between available acid quantity and theoretical acid quantity. The theoretical acid quantity is determined based on the liquid level, pH, and physical properties of the waste liquid in the alkaline buffer tank, while the available acid quantity is determined based on the liquid level, physical properties of the waste liquid in the acid buffer tank, and the geometric parameters of the tank.

[0026] In this embodiment, the liquid level is determined based on the monitoring of a liquid level gauge installed in the buffer tank; the pH is determined based on the monitoring of an industrial-grade online pH meter installed in the buffer tank; the physical properties of the waste liquid include the conductivity, density, and temperature of the waste liquid; the conductivity of the waste liquid is determined based on the monitoring of an industrial-grade conductivity meter with a corrosion-resistant lining installed in the buffer tank; the density of the waste liquid is determined based on the monitoring of a tuning fork-type online density meter installed in the buffer tank; and the temperature of the waste liquid is determined based on the monitoring of a resistance temperature detector installed in the buffer tank.

[0027] Step S4: Based on the wastewater treatment strategy, determine the operating mode of the waste liquid extraction equipment, the dosing rate of the acidic agent, the dosing source, and the target amount of acid to be added; Step S5: Determine whether to perform acid-base fine-tuning based on the neutralization addition ratio, wherein the neutralization addition ratio is determined based on the target amount of acid added and the actual amount added during the real-time mixing reaction process; In this embodiment, the actual dosage is determined by time integration calculation based on the instantaneous flow rate measured by the flow meter installed on the dosing pipeline.

[0028] Step S6: In response to the determination result of the acid-base fine adjustment, based on the deviation between the acidity and alkalinity during the mixing reaction process and the target precipitation range obtained in real time, determine the fine adjustment working frequency of the acid reagent dosing equipment.

[0029] Specifically, in the entire process of etching wastewater separation collection and neutralization treatment, this invention addresses the issue that the instantaneous mixing of acidic and alkaline wastewater can easily induce irreversible precipitation. First, acid and alkali are separated through signal mapping. Then, considering the risk of hydrolysis and pipe blockage due to environmental temperature drops during the discharge of high-alkali wastewater, multi-source physical property parameters are used to quantify supersaturation for dynamic heating and blockage prevention. After the wastewater safely enters the tank, due to large batch-to-batch water quality fluctuations, blind addition can easily lead to acid-base imbalance. Therefore, supply and demand equivalence is calculated to guide macro-level scheduling. During the strategy execution phase, given the nonlinear abrupt characteristics of the neutralization reaction, continuous and extensive addition can easily lead to pH overshoot. Therefore, a dosage ratio threshold is introduced for smooth fine-tuning. Finally, at the end of the fine-tuning phase, a closed-loop fine-tuning is performed based on the required sedimentation range, thereby solving the combined problem of pipeline blockage and uncontrolled neutralization at the end of etching wastewater treatment.

[0030] Please see Figure 2 As shown, this is a flowchart of the waste liquid collection process using the entire pipeline valve network in this embodiment. In this embodiment, the process of controlling the switching of the pipeline valve array during waste liquid collection based on the type of waste liquid and performing independent buffer pool collection includes: In response to the batch discharge trigger signal, the tank identifier is entered into the preset tank type table for lookup and interpolation to determine whether the waste liquid is high-alkali waste liquid or high-acid waste liquid; In response to the determination that the waste liquid is of high alkalinity, the valve of the alkaline liquid diversion pipeline is opened and the valve of the acid liquid diversion pipeline is closed to introduce the waste liquid into the alkaline liquid buffer tank for independent collection. In response to the determination that the waste liquid is of high acid type, the valve of the acid diversion pipeline is opened and the valve of the alkali diversion pipeline is closed to introduce the waste liquid into the acid buffer tank for independent collection.

[0031] In this embodiment, the preset tank type table is established based on the equipment configuration of the production line. The tank identifiers in the production line are associated with their corresponding process types, and the corresponding waste liquid type is recorded according to the acid-base properties of the waste liquid generated by the corresponding process. After the control system receives the current discharge tank identifier, it obtains the corresponding waste liquid type by querying the preset tank type table, and then outputs the judgment result of high alkaline waste liquid or high acid waste liquid.

[0032] Specifically, due to the large instantaneous impact of waste liquid in the alternating acid and alkali etching of aluminum alloys, which easily leads to irreversible gel precipitation, the acid and alkali properties of the waste liquid are determined by obtaining the batch discharge trigger signal and tank identification, querying the preset tank type table, and controlling the interlocking switching of the pipeline valve array accordingly to achieve separate collection, avoiding the mixing and scaling of acid and alkali waste liquid in the collection pipeline, and providing an independent material basis for subsequent pipeline heating anti-blocking and acid-alkali neutralization treatment.

[0033] Please see Figure 3 As shown, this is a flowchart for determining the supersaturation degree in this embodiment. In this embodiment, the process of determining the supersaturation degree includes: Based on online temperature, online conductivity, and online density, the actual concentration of sodium aluminate is determined according to a preset sodium aluminate solution composition correlation model, so as to determine the true solute content of sodium aluminate under the current working conditions. Based on the online temperature and actual concentration value, the equilibrium concentration value of sodium aluminate is determined according to the empirical formula of thermodynamic equilibrium, so as to determine the theoretical limit value of the solution that can accommodate sodium aluminate without hydrolysis and precipitation at this temperature. Calculate the difference between the actual concentration value and the equilibrium concentration value to obtain the concentration difference, and then determine the absolute amount of excess solute driving the hydrolysis and crystallization reaction; The supersaturation is obtained by calculating the ratio of the concentration difference to the equilibrium concentration, which helps determine the potential risk of aluminum hydroxide gel being released from the solution due to cooling and hydrolysis.

[0034] In this embodiment, a preset sodium aluminate solution composition correlation model is used to determine the correspondence between online temperature, online conductivity, online density and the actual concentration of sodium aluminate. The correspondence can be pre-established based on the calibration results of standard sodium aluminate solution samples. During operation, the actual concentration value of sodium aluminate is determined based on the real-time acquired online temperature, online conductivity and online density, combined with the correspondence.

[0035] In this embodiment, the thermodynamic equilibrium empirical formula adopts the Misra formula recognized in the alumina industry. Its essence is a fitting function that characterizes the exponential decay of equilibrium concentration with alkalinity and temperature. Its function structure and preset constants are established by a large number of historical thermodynamic solubility experiments and are publicly defined in industry literature. No additional training is required. The equilibrium concentration limit can be calculated by substituting the online temperature and the aforementioned actual concentration value.

[0036] Please see Figure 4 As shown, this is a flowchart for determining the pipeline heat tracing parameters in this embodiment. In this embodiment, the process of determining the pipeline heat tracing parameters includes: Calculate the difference between the online temperature and the pipeline temperature to obtain the pipe-liquid temperature difference, so as to determine the cooling impact intensity of the waste liquid when it enters the non-thermostatic pipeline from the thermostatic tank. Based on the judgment that the temperature difference between the liquid and the pipe is greater than the preset temperature difference threshold and the supersaturation is greater than the preset supersaturation threshold, the pipe temperature is increased. The increase is positively correlated with the difference between the liquid temperature difference and the preset temperature difference threshold, so as to forcibly intervene and inhibit the formation of hydrolytic gel when the waste liquid is simultaneously facing a severe cooling shock and the risk of thermodynamic precipitation.

[0037] In this embodiment, the preset temperature difference threshold is determined based on the safe cooling gradient of sodium aluminate solution in a non-thermostatic pipeline. The waste liquid will inevitably undergo natural cooling when discharged from the thermostatic tank into the environmental pipeline. This threshold defines the maximum allowable temperature drop limit of the waste liquid under conditions that do not trigger rapid hydrolysis kinetics. Below this threshold, the cooling rate is slow, and the system is not sufficient to generate a large amount of gel by its own thermal stability.

[0038] In this embodiment, the preset supersaturation threshold is determined based on the thermodynamic metastable limit of sodium aluminate in the current waste liquid system, so as to determine the critical concentration point at which aluminum hydroxide precipitates from the solute in the solution; below this threshold, the solution has sufficient solubility buffer space, and phase change precipitation is not likely to occur even if there is a temperature drop disturbance.

[0039] Specifically, since highly alkaline wastewater is easily affected by ambient temperature fluctuations when discharged into non-constant temperature pipe networks, the actual concentration of sodium aluminate is calculated by back-calculation and converted into a quantifiable supersaturation index using thermodynamic formulas. This maps the invisible temperature drop into a specific precipitation risk. Furthermore, considering that not all temperature drops in actual operating conditions will lead to substantial scaling, a dual boundary judgment is made between the temperature difference, which characterizes the cooling impact, and the supersaturation, which characterizes the thermodynamic metastable limit. Only when both kinetic and thermodynamic risks exceed the limits is the heat tracing compensation dynamically increased proportionally to the degree of temperature difference deviation to reduce the supersaturation of sodium aluminate, thereby delaying or preventing its hydrolysis reaction and preventing the precipitation and adhesion of aluminum hydroxide solids on the pipe wall.

[0040] In this embodiment, the process of determining the amount of available acid includes: Calculate the difference between the liquid level in the acid buffer tank and the height of the dead zone to obtain the acid height difference; The volume of waste acid is obtained by multiplying the height difference of the acid solution by the cross-sectional area of ​​the bottom of the buffer tank, so as to quantify the physical spatial state of the acid solution in the buffer tank. Based on the conductivity, density, and temperature of the waste liquid, the effective acid concentration of sodium aluminate is determined according to a pre-set acid composition correlation model, so as to determine the chemical neutralization capacity of a unit volume of acid liquid. The product of the waste acid volume and the effective acid concentration is calculated to obtain the available acid quantity, which is then used to determine the total neutralization equivalent available for dispatch under the current operating conditions.

[0041] In this embodiment, the preset acid composition correlation model is based on offline preparation of various waste acid standard samples covering the concentration gradient of actual working conditions. Conductivity and density data at different temperatures are collected simultaneously. A set of equations characterizing the mapping relationship between temperature, conductivity, density and effective acid concentration is fitted and calibrated using a multivariate nonlinear regression method and then fixed in the control system. When running online, the effective acid concentration value can be calculated simply by substituting the three parameters collected in real time from the acid buffer tank.

[0042] In this embodiment, the dead zone height and the bottom cross-sectional area of ​​the buffer tank are both inherent parameters of the acid buffer tank and the alkali buffer tank, wherein the dead zone height is the distance from the pump inlet to the bottom of the tank.

[0043] In this embodiment, the process of determining the theoretical acidity includes: Calculate the difference between the liquid level in the alkaline buffer tank and the height of the dead zone to obtain the alkaline liquid height difference; The volume of waste alkali is obtained by multiplying the height difference of the alkali solution by the cross-sectional area of ​​the bottom of the buffer tank, so as to quantify the total physical space of the waste liquid to be neutralized in each fractional buffer tank. The pH, conductivity, and density of the alkaline buffer tank are input into a preset alkalinity mapping table and interpolation is performed to determine the actual effective alkalinity value of the waste liquid. This breaks through the measurement limitations of a single pH value in strong alkaline and high buffer systems and accurately quantifies the amount of hydrogen ion equivalent required per unit volume of waste liquid. The theoretical acid quantity is obtained by multiplying the volume of waste alkali by the actual effective alkalinity value, which determines the theoretical absolute amount of acidic substance required to completely neutralize the current batch of waste liquid to the target precipitation range.

[0044] In this embodiment, the preset alkalinity mapping table is a pre-established correspondence table that records the actual effective alkalinity values ​​corresponding to different combinations of pH, conductivity, and density. During operation, the pH, conductivity, and density acquired in real time are used as query conditions to determine the corresponding actual effective alkalinity values ​​in the preset alkalinity mapping table, so as to determine the actual alkalinity of the waste liquid participating in the neutralization reaction.

[0045] In this embodiment, the process of determining the wastewater treatment strategy includes: Based on the determination that the available acid quantity is greater than the preset minimum guaranteed acid quantity, the difference between the available acid quantity and the preset minimum guaranteed acid quantity is calculated to obtain the net available acid quantity, so as to determine the actual limit of acid equivalent that can participate in the neutralization reaction under the premise of ensuring that the end of the pipeline is kept acidic. Based on the determination that the net available acid quantity is greater than or equal to the theoretical acid quantity, the wastewater treatment strategy is determined to be a full mixing strategy. Based on the judgment that the net available acid quantity is less than the theoretical acid quantity and the liquid level of the alkaline buffer tank is less than the preset overflow warning height, the wastewater treatment strategy is determined to be a flow-limited batch mixing strategy to consume the current stock of waste acid without introducing external acid sources. Based on the judgment that the net available acid quantity is less than the theoretical acid quantity and the liquid level of the alkaline buffer tank is greater than or equal to the preset overflow warning height, the wastewater treatment strategy is determined to be a supplementary commercial acid source strategy, in order to introduce a commercial acid source to supplement the acid quantity gap required for neutralizing the waste alkali.

[0046] In this embodiment, the minimum guaranteed acid quantity is preset to a controlled and unusable chemical equivalent bottom line above the dead zone liquid level. Its value is determined by multiplying the critical liquid level height required to maintain acid sealing at the end of the pipeline, the bottom cross-sectional area of ​​the buffer tank corresponding to the liquid level, and the current effective acid concentration value. After the batch discharge is completed, the acid in the physical liquid level range corresponding to the above equivalent bottom line is not extracted, but is left in the tank and flows back with the pipeline residual liquid, continuously inhibiting the high alkaline waste liquid attached to the pipeline dead zone from undergoing sodium aluminate hydrolysis and scaling.

[0047] In this embodiment, the preset overflow warning height is determined based on the upper limit of the safe volume of the alkaline buffer tank or the continuous discharge load of the production line. When the amount of available waste acid is lower than the neutralization requirement and the liquid level of the alkaline buffer tank reaches the preset overflow warning height, the system terminates the flow restriction and batch mixing strategy and directly switches to the strategy of supplementing commercial acid source to prevent waste liquid overflow and ensure production continuity.

[0048] Specifically, since the neutralization equivalent cannot be calculated due to the distortion of single pH values ​​in the strong buffering system of etching waste liquid, a lookup table method is used to remove the apparent illusion and quantify the actual effective alkalinity to accurately back-calculate the theoretical acid quantity requirement. Furthermore, since pipeline dead zones are prone to secondary hydrolysis and scaling caused by acid depletion, a minimum unusable guaranteed acid quantity is defined to maintain acid sealing, and the true net usable acid quantity is calculated accordingly. Finally, based on the dynamic gap between theoretical demand and net inventory, and combined with the treatment requirements of waste alkali liquid, an adaptive matching hierarchical scheduling strategy of full mixing, limited batching, or commercial supplementation is adopted. This achieves accurate offsetting of acid and alkali material equivalents while avoiding the risk of structural blockage caused by damage to the anti-corrosion barrier in pipeline dead zones.

[0049] In this embodiment, the process of determining the operating mode of the waste liquid extraction equipment, the dosing rate of the acidic agent, the dosing source, and the target amount of acid to be added includes: In response to the full mixing strategy, the operating mode of the waste liquid extraction equipment is determined to be continuous operation mode, so as to pump the waste liquid in the alkaline buffer tank to the mixing reaction zone in one go to participate in the neutralization reaction. The source of acidic reagent addition was determined to be waste acid in the acid buffer tank, and the theoretical acid amount was used as the target acid addition amount for the current batch, so as to clarify the source of reagents and establish a master reactant baseline based on the existing waste acid. Calculate the ratio of the target acid dosage to the effective acid concentration to obtain the theoretical acid volume; The ratio of waste alkali volume to theoretical acid volume is calculated to obtain the mixing flow ratio, so as to quantify the dynamic ratio of the main and auxiliary material flows and eliminate the interference of concentration difference on the pipeline mixing uniformity. Calculate the ratio of the preset baseline flow rate to the mixed flow rate to obtain the dosing rate of the acid reagent dosing pump, so as to simultaneously extract waste alkali and add waste acid.

[0050] In this embodiment, the waste liquid extraction device is an alkali pump for extracting alkaline waste liquid. The preset reference flow rate is the target delivery flow rate of the alkali pump, which is calculated and determined based on the ratio of the effective volume of the mixing reaction zone to the hydraulic residence time required to satisfy the full neutralization reaction.

[0051] In response to the flow-limiting and batch mixing strategy, the operating mode of the waste liquid extraction equipment is determined to be the quantitative operation mode, so as to limit the single processing load when the acid liquid is limited, and avoid the system shutdown due to material imbalance. The source of acidic reagent addition was determined to be waste acid in the acid buffer tank, and the net available acid volume was used as the target acid addition amount for the current batch. Calculate the ratio of the target acid dosage to the actual effective alkalinity value to obtain the volume of waste alkali that can be treated in a single batch, so as to determine the treatable load and realize batch treatment based on acid-based alkali determination; Calculate the ratio of the target acid dosage to the effective acid concentration to obtain the theoretical acid volume; Calculate the ratio of the volume of waste alkali that can be treated in a single batch to the theoretical volume of acid to obtain the mixing flow ratio; Calculate the ratio of the preset baseline flow rate to the mixed flow rate to obtain the dosing rate of the acid reagent dosing pump; When the cumulative amount of waste liquid extracted reaches the actual treatable volume of waste alkali in a single operation, the waste liquid extraction equipment is automatically shut down. Once the liquid level in the acid buffer tank rises and the available acid quantity meets the treatment conditions again, the next round of flow-limited batch mixing cycle is automatically triggered.

[0052] In response to the strategy of supplementing commercial acid sources, the operating mode of the waste liquid extraction equipment is determined to be continuous operation mode, so as to pump the waste liquid in the alkaline buffer tank to the mixing reaction zone to participate in the forced neutralization reaction. The source of acidic reagent addition was determined to be an externally connected commercial acid source, and the theoretical acid content was used as the target acid addition amount for the current batch of treatment, so as to force a switch to an external high-concentration acid source when the stock of waste acid was depleted and the waste alkali faced the risk of overflow. Calculate the ratio of the target amount of acid to the nominal concentration of commercial acid to obtain the theoretical volume of commercial acid required; Calculate the ratio of waste alkali volume to theoretical acid volume to obtain the mixing flow ratio for commercial acid sources; The ratio of the preset baseline flow rate to the mixed flow rate is calculated to obtain the dosing acceleration rate of the acidic agent dosing pump.

[0053] In this embodiment, the nominal concentration of commercial acid is an inherent parameter of the externally connected commercial acid source obtained from the control system.

[0054] In this embodiment, the process of determining whether to perform acid-base fine-tuning includes: The neutralization dosage ratio is obtained by calculating the ratio of the actual dosage to the target acid dosage corresponding to the current batch. Based on the determination that the neutralization dosing ratio is less than the preset ratio threshold, the current operating mode and dosing rate of the mixing pump are maintained and coarse dosing is continued. Based on the determination that the neutralization dosing ratio is greater than or equal to the preset ratio threshold, it is determined that the operation mode of the mixing pump will be switched to the low-speed buffer dosing mode, and acid-base fine adjustment will be performed.

[0055] In this embodiment, the preset ratio threshold is determined in advance based on the test results of the neutralization process of the target etching waste liquid and stored in the control system. By testing the changes in pH under different neutralization addition ratios, the neutralization addition ratio corresponding to the rapid change in pH is determined as the preset ratio threshold, which serves as the basis for determining the switch from coarse addition to fine pH adjustment.

[0056] Specifically, due to the acid-base equivalent imbalance caused by batch shocks, the macroscopic dosing rate and alkali extraction rate are synchronously controlled or quantitatively allocated based on the supply-demand equivalent to solve the problem of basic ratio imbalance under extensive dosing. Furthermore, considering the extreme working conditions of depletion of existing waste acid and overflow of waste alkali, the waste acid pipeline is forcibly cut off and switched to a high-concentration commercial acid source to re-establish the ratio and ensure continuous treatment. On this basis, given that aluminum-containing waste liquid has a nonlinear jump and pipeline mixing delay when approaching the neutralization endpoint, continuous extensive dosing is very likely to cause pH overshoot. Therefore, a comparison mechanism between the neutralization dosing ratio and the preset ratio threshold is introduced as a physical braking point. When the extensive dosing progress reaches this critical value, it is forcibly switched to a low-speed buffer fine-tuning state to avoid the risk of end-of-pipe dosing runaway caused by batch fluctuations and nonlinear reaction.

[0057] In this embodiment, the process of determining the fine-tuning operating frequency includes: Calculate the difference between the pH and the median value of the target precipitation range to obtain the target deviation, and then determine the offset distance from the target. The preset basic operating frequency is adjusted according to the target deviation to obtain the adjusted operating frequency. When the target deviation is greater than zero, the preset basic operating frequency is increased, and the increase is positively correlated with the target deviation. When the target deviation is less than zero, the preset basic operating frequency is decreased, and the decrease is positively correlated with the absolute value of the target deviation. In response to the determination result of whether the wastewater treatment strategy is a full-volume mixing strategy or a limited-flow batch mixing strategy, the fine-tuning working frequency is determined to be the adjustment working frequency, so as to use the existing waste acid to complete the final fine-tuning. In response to the determination result of the wastewater treatment strategy as a supplementary commercial acid source strategy, the ratio of the nominal concentration of commercial acid to the effective acid concentration is calculated to obtain the concentration ratio, so as to convert the control actions calibrated for low-concentration waste acid into actual pumping actions adapted to high-concentration commercial acid. Calculate the ratio of the adjusted working frequency to the concentration ratio to obtain the fine-tuned working frequency, so as to eliminate the risk of pH overshoot and precipitate re-dissolution caused by the stepwise jump in acid concentration.

[0058] In this embodiment, the target precipitation range is determined based on the wastewater discharge standards or the influent water quality requirements of the subsequent treatment process. In order to meet the restrictions on heavy metal removal rate and effluent pH value in the standard, aluminum ions in the waste liquid need to be converted into solid precipitate. Combining the amphoteric solubility characteristics of aluminum hydroxide, the pH range that can achieve complete precipitation of aluminum ions without back dissolution is set as the target precipitation range.

[0059] In this embodiment, the preset basic operating frequency is determined based on the minimum hydraulic disturbance threshold value that keeps the aluminum hydroxide flocs suspended and prevents them from settling in the mixing reaction tank. During the closed-loop control process, even if the target deviation approaches zero, the dosing pump still maintains the preset basic operating frequency at a low frequency. By continuously inputting trace amounts of reagent, it generates micro-disturbances in the fluid, thus eliminating the risk of floc caking and pipeline deposition caused by fluid stasis at the end of the fine-tuning period from a fluid dynamics perspective.

[0060] Specifically, because the aluminum hydroxide generated at the end of the neutralization reaction of aluminum-containing wastewater has amphoteric characteristics, it will dissolve back in either excessively acidic or excessively alkaline environments. Therefore, the median value of the target sedimentation range that meets the emission standards is selected to calculate the current pH deviation to guide the dosing. Near the neutralization endpoint, due to the significant reduction in the dosing amount, the fluid velocity in the reaction tank decreases, and aluminum hydroxide flocs easily settle and adhere to the pipe walls under low-disturbance conditions, causing blockage. Therefore, the dosing pump is set to a non-zero preset base operating frequency and runs continuously, maintaining hydraulic agitation conditions in the tank through a small amount of reagent fluid input. Above this base frequency, the system adjusts the operating frequency by increasing or decreasing it according to the magnitude of the pH deviation, gradually bringing the pH closer to the neutralization endpoint. If the current treatment strategy is to supplement commercial acid sources, since the effective hydrogen ion concentration of commercial acid is much greater than that of waste acid, the dosing volume at the same frequency will introduce excessive acid and cause a sudden drop in pH. At this time, the system calculates the concentration ratio between the nominal concentration of commercial acid and the effective concentration of waste acid, and divides the adjusted operating frequency by this concentration ratio to reduce the actual operating frequency of the dosing pump, thereby matching the dosing equivalent per unit time under low-concentration waste acid conditions and avoiding local overshoot caused by step changes in acid concentration.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for treating etching wastewater based on multi-source data fusion, characterized in that, include: The switching of the pipeline valve array is controlled based on the waste liquid type during the waste liquid collection process, and independent buffer tank collection is carried out. The waste liquid type is determined based on the batch discharge trigger signal and tank identification obtained in real time from the production line control system. In response to the determination that the waste liquid is a high-alkali waste liquid, the pipeline heating parameters during the process of discharging the waste liquid into the pipeline are determined based on the pipe liquid temperature difference, supersaturation and preset benchmark threshold. The supersaturation is determined based on the real-time acquired online temperature, online conductivity and online density, and the pipe liquid temperature difference is based on the real-time acquired pipeline temperature and online temperature. Wastewater treatment strategies are determined based on the comparison between available acid quantity and theoretical acid quantity, as well as the liquid level of the alkaline buffer tank. The theoretical acid quantity is determined based on the liquid level, pH, and physical properties of the waste liquid in the alkaline buffer tank, while the available acid quantity is determined based on the liquid level, physical properties of the waste liquid, and geometric parameters of the tank in the acid buffer tank. Based on the aforementioned wastewater treatment strategy, the operating mode of the waste liquid extraction equipment, the dosing rate of the acidic agent, the dosing source, and the target amount of acid to be added are determined. Whether to perform acid-base fine-tuning is determined based on the neutralization addition ratio, wherein the neutralization addition ratio is determined based on the target amount of acid added and the actual amount added during the real-time acquisition of the mixing reaction process; In response to the determination result of the acid-base fine-tuning, the fine-tuning frequency of the acid reagent dosing equipment is determined based on the deviation between the acidity and alkalinity during the mixing reaction process and the target precipitation range, which is acquired in real time.

2. The etching wastewater treatment method based on multi-source data fusion according to claim 1, characterized in that, The process of controlling the switching of pipeline valve arrays during waste liquid collection based on waste liquid type and performing independent buffer pool collection includes: In response to the batch discharge trigger signal, the waste liquid type is determined to be either high-alkali waste liquid or high-acid waste liquid based on the tank identifier and the preset tank type table; In response to the determination that the waste liquid is of high alkalinity, the valve of the alkaline liquid diversion pipeline is opened and the valve of the acid liquid diversion pipeline is closed. In response to the determination that the waste liquid is of the high acid type, the valve of the acid diversion pipeline is opened and the valve of the alkali diversion pipeline is closed.

3. The etching wastewater treatment method based on multi-source data fusion according to claim 2, characterized in that, The process of determining supersaturation includes: Supersaturation is determined based on the concentration difference and equilibrium concentration values, where, The concentration difference is determined based on the actual concentration value and the equilibrium concentration value. The actual concentration value is determined based on the online temperature, the online conductivity, and the online density. The equilibrium concentration value is determined based on the online temperature and the actual concentration value.

4. The etching wastewater treatment method based on multi-source data fusion according to claim 3, characterized in that, The process of determining pipeline heat tracing parameters includes: Based on the comparison results between the pipe fluid temperature difference and the preset temperature difference threshold, and the comparison results between the supersaturation and the preset supersaturation threshold, the pipe temperature is adjusted according to the pipe fluid temperature difference and the preset temperature difference threshold. The temperature difference between the liquid and the tubing is determined based on the online temperature and the tubing temperature.

5. The etching wastewater treatment method based on multi-source data fusion according to claim 4, characterized in that, The process of determining the amount of available acid includes: The amount of usable acid is determined based on the volume of waste acid and the effective acid concentration, wherein... The volume of waste acid is determined based on the liquid level, dead zone height, and bottom cross-sectional area of ​​the acid buffer tank, while the effective acid concentration is determined based on the waste liquid conductivity, waste liquid density, and waste liquid temperature.

6. The etching wastewater treatment method based on multi-source data fusion according to claim 5, characterized in that, The process of determining the theoretical acidity includes: The theoretical acid quantity is determined based on the volume of waste alkali and the actual effective alkalinity value, where, The volume of waste alkali is determined based on the liquid level, dead zone height, and bottom cross-sectional area of ​​the alkaline buffer tank. The actual effective alkalinity value is determined based on the pH of the alkaline buffer tank, the conductivity of the waste liquid, and the density of the waste liquid.

7. The etching wastewater treatment method based on multi-source data fusion according to claim 6, characterized in that, The process of determining a wastewater treatment strategy includes: Based on the determination result that the available acid quantity is greater than the preset minimum guaranteed acid quantity, the net available acid quantity is determined according to the available acid quantity and the preset minimum guaranteed acid quantity; Based on the determination result that the net available acid quantity is greater than or equal to the theoretical acid quantity, the wastewater treatment strategy is determined to be a full mixing strategy. Based on the determination that the net available acid quantity is less than the theoretical acid quantity and the liquid level of the alkaline buffer tank is less than the preset overflow warning height, the wastewater treatment strategy is determined to be a flow-limited batch mixing strategy. Based on the determination that the net available acid quantity is less than the theoretical acid quantity and the liquid level of the alkaline buffer tank is greater than or equal to the preset overflow warning height, the wastewater treatment strategy is determined to be a supplementary commercial acid source strategy.

8. The etching wastewater treatment method based on multi-source data fusion according to claim 7, characterized in that, The process of determining the operating mode of the waste liquid extraction equipment, the dosing rate of the acidic reagent, the dosing source, and the target acid dosage includes: In response to the full-volume mixing strategy, the operating mode of the waste liquid extraction equipment is determined to be continuous operation mode, and the source of the acidic agent is determined to be waste acid in the acid buffer tank. The theoretical acid volume is used as the target acid dosage, and the dosing rate is determined based on the waste alkali volume and the theoretical acid volume. The theoretical acid volume is determined based on the target amount of acid added and the effective acid concentration. In response to the flow-limiting, batch-mixing strategy, the operating mode of the waste liquid extraction equipment is determined to be a quantitative operating mode. The source of the acidic agent is determined to be the waste acid in the acid buffer tank. The net available acid volume is used as the target acid dosage, and the dosing rate is determined based on the single-batch treatable waste alkali volume and the theoretical acid volume. The volume of waste alkali that can be processed in a single batch is determined based on the target amount of acid added and the actual effective alkalinity value. In response to the aforementioned supplemental commercial acid source strategy, the operating mode of the waste liquid extraction equipment is determined to be the continuous operation mode, the dosing source of the acidic agent is determined to be an externally connected commercial acid source, and the theoretical acid amount is used as the target acid dosing amount. The dosing rate is determined based on the nominal concentration of the commercial acid liquid, the target acid dosing amount, and the volume of waste alkali.

9. The etching wastewater treatment method based on multi-source data fusion according to claim 8, characterized in that, The process of determining whether to perform acid-base fine-tuning includes: Based on the comparison between the neutralization dosage ratio and the preset ratio threshold, it is determined whether to perform the acid-base fine-tuning, wherein... The neutralization dosage ratio is determined based on the actual dosage and the target acid dosage.

10. The etching wastewater treatment method based on multi-source data fusion according to claim 9, characterized in that, The process of determining the fine-tuning operating frequency of the acidic reagent dosing pump includes: The preset basic operating frequency is adjusted according to the target deviation to obtain the adjusted operating frequency, wherein the target deviation is determined based on the pH and the median value of the target precipitation range; In response to the determination result that the wastewater treatment strategy is the full-volume mixing strategy or the flow-limited batch mixing strategy, the fine-tuning operating frequency is determined to be the adjustment operating frequency. In response to the determination that the wastewater treatment strategy is the supplementary commercial acid source strategy, the fine-tuning operating frequency is determined based on the adjusted operating frequency and concentration ratio, wherein the concentration ratio is determined based on the nominal concentration of the commercial acid and the effective acid concentration.

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