A system and method for treating and recovering control of acid waste water

Abstract

The present application belongs to the technical field of industrial wastewater treatment and automatic control, and relates to a kind of acid-making wastewater treatment recovery control system and method.The present application calculates lime mud basic dosage and formulates phased dosing scheme through initial dosing control module;Through dynamic dosing control module, neutralization performance coefficient is calculated based on pH change and dosage, and subsequent dosage is dynamically adjusted, and neutralization stagnation state is identified to take trial dosing;Through the precipitation analysis adjustment module, the precipitation process is monitored, the precipitation rate is calculated, and the adjustment factor is generated.The technical problems of inaccurate lime mud dosage control, low neutralization efficiency and unstable precipitation effect in traditional acid-making wastewater treatment are solved, and the technical effects of improving wastewater treatment automation, optimizing reagent use efficiency and ensuring stable effluent quality are achieved.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment and automatic control technology, and relates to a control system and method for the treatment and recycling of acid production wastewater. Background Technology

[0002] Sulfuric acid production wastewater mainly originates from the production processes of industries such as metallurgy and chemicals. It contains large amounts of acidic substances such as sulfuric acid and hydrochloric acid. If discharged directly without proper treatment, it will cause serious pollution to water bodies and the environment. Currently, the main treatment method for sulfuric acid production wastewater is neutralization, aiming to purify and reuse the wastewater.

[0003] In the prior art, various improvement schemes have emerged to enhance the utilization rate and neutralization efficiency of lime. For example, Chinese Invention Patent Publication No. CN109835974A proposes a method for treating acidic wastewater using lime, which improves reaction efficiency by introducing ultrasonic vibration to break down precipitates.

[0004] However, this method's control mechanism primarily relies on detecting the pH value of the clarified liquid during the reaction process to determine whether lime slurry needs to be added. Its control logic is essentially based on delayed feedback of the final result, rather than real-time tracking and forward-looking planning of the reaction process. Furthermore, the entire lime slurry addition process cannot achieve precise automatic control and depends on manual intervention by experienced operators. This not only increases labor costs and operational risks but also results in low control accuracy when dealing with different batches of wastewater, making it difficult to meet the demands of modern industrial automation.

[0005] Due to limitations in the ability to dynamically sense and model key parameters of the reaction process, existing systems often use preset or fixed modes for dosage and acceleration. This leads to frequent problems of insufficient neutralization or overdosing when wastewater quality, acidity, or composition fluctuates, as the system cannot adaptively adjust. The former results in unqualified effluent pH, while the latter directly leads to waste of lime slurry and significantly increases the subsequent sludge treatment load and disposal costs due to increased sludge production.

[0006] In traditional processing, neutralization and precipitation are often treated separately, lacking data feedback and optimization mechanisms between batches. This prevents the system from extracting effective information from the sedimentation performance reflected in the current batch and using it to optimize the neutralization agent dosing strategy for the next batch. This open-loop processing mode makes the entire system lack self-learning and continuous optimization capabilities, and it operates in a suboptimal state for a long time, which restricts the improvement of processing efficiency and economy. Summary of the Invention

[0007] In view of this, in order to solve the problems mentioned in the background art, a control system and method for the treatment and recycling of acid production wastewater are proposed.

[0008] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides an acid production wastewater treatment and recycling control system, including the following modules: an initial dosing control module, used to obtain the initial pH value and volume of the acid production wastewater to be treated, calculate the basic amount of lime slurry required to neutralize the acidity, and add the lime slurry to the sedimentation chamber in stages according to the initial dosing scheme.

[0009] The dynamic dosing control module is used to determine the neutralization performance coefficient of the current stage based on the change in pH before and after the dosing and the amount of lime slurry added in the current stage within the reaction time after the completion of each dosing stage. Based on the coefficient, it determines whether the amount of lime slurry added in the next dosing stage needs to be adjusted. Based on the judgment result and whether the system is in a neutralization stagnation state, it generates the dosing control command for the next dosing stage.

[0010] The sedimentation analysis and adjustment module is used to calculate the sedimentation ratio sequence based on the interface position sequence and corresponding timestamps obtained by the interface detector during the settling stage after the lime slurry is added. The sedimentation rate is obtained through linear regression, and an adjustment factor is generated to correct the basic addition amount of lime slurry for the next batch.

[0011] The second aspect of the present invention provides a method for controlling the treatment and recycling of acid wastewater, comprising the following steps: S1, obtaining the initial pH value and volume of the acid wastewater to be treated, calculating the basic amount of lime slurry required to neutralize the acidity, and adding the lime slurry to the sedimentation chamber in stages according to the initial addition plan.

[0012] S2. During the reaction time after each addition stage is completed, determine the neutralization performance coefficient of the current stage based on the change in pH before and after the addition of that stage and the amount of lime slurry added in that stage.

[0013] S3. Determine whether the amount of lime slurry added in the next addition stage needs to be adjusted based on the neutralization performance coefficient, and generate the addition control command for the next addition stage based on the judgment result and whether the system is in a neutralization stagnation state.

[0014] S4. During the settling stage after the lime slurry is added, the sedimentation ratio sequence is calculated based on the interface position sequence and corresponding timestamps collected by the interface detector.

[0015] S5. Perform linear regression on the sedimentation ratio sequence to obtain the sedimentation rate, and generate an adjustment factor for correcting the basic dosage of the next batch of lime slurry.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention introduces a basic dosage calculation based on the initial pH value and wastewater volume, and adopts a phased exponential decay dosage scheme to achieve precise automatic control of the lime slurry dosage process. This effectively solves the problems of relying on human experience intervention and lagging control logic in the prior art. This method structures and quantifies the dosage process, enabling the system to reasonably allocate the dosage in the early stage, reduce the single dependence on the final pH result, reduce labor costs and operational risks, and adapt to the treatment needs of different batches of wastewater.

[0017] (2) This invention dynamically calculates the neutralization performance coefficient and determines in real time whether to adjust the dosage in the next stage. The system can adaptively adjust the lime slurry dosage according to the actual reaction process, which solves the problem of insufficient or excessive neutralization caused by the preset or fixed dosage mode in the prior art. This method dynamically models based on pH changes and dosage history, so that the system can maintain neutralization accuracy when water quality fluctuates. It ensures that the pH of the effluent meets the standard, saves lime dosage to the maximum extent, and reduces the subsequent treatment load and disposal cost.

[0018] (3) This invention constructs a cross-batch feedback mechanism for the neutralization addition strategy of the precipitation process by analyzing the precipitation process during the static stage and generating an adjustment factor for correcting the basic addition amount of the next batch. This solves the problem that the batch processing in the traditional system is isolated from each other and lacks self-learning and continuous optimization capabilities based on precipitation performance. This method uses sedimentation characteristic parameters such as precipitation rate to optimize the neutralization addition amount of subsequent batches, so that the system has the ability to iteratively learn based on historical precipitation effects and realize continuous process optimization. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram showing the connection of each module in the acid production wastewater treatment and recycling control system of the present invention.

[0021] Figure 2 This is a flowchart of the method for obtaining the neutralization performance coefficient in this invention.

[0022] Figure 3 This is a flowchart illustrating the steps of a method for controlling the treatment and recycling of acid production wastewater according to the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] Please see Figure 1 As shown, the present invention provides an acid production wastewater treatment and recovery control system, including: an initial dosing control module, a dynamic dosing control module, and a sedimentation analysis and adjustment module. The connection relationship between the modules is as follows: the initial dosing control module and the dynamic dosing control module are connected, the dynamic dosing control module and the sedimentation analysis and adjustment module are connected, and the sedimentation analysis and adjustment module and the initial dosing control module are connected.

[0026] The initial dosing control module is used to obtain the initial pH value and volume of the acid wastewater to be treated, calculate the basic amount of lime slurry required to neutralize the acidity, and add the lime slurry to the sedimentation chamber in stages according to the initial dosing plan.

[0027] Furthermore, the method for obtaining the basic dosage is as follows: the concentration of hydrogen ions in the wastewater is calculated based on the initial pH value of the obtained acid production wastewater.

[0028] Considering that the acid production wastewater mainly contains strong acids such as sulfuric acid and hydrochloric acid, and its acidity can be reflected by the pH value, while the neutralization reaction requires precise addition based on stoichiometry, the pH value must first be converted into hydrogen ion concentration.

[0029] The total amount of hydrogen ions in the wastewater is calculated based on the obtained volume of acid production wastewater and the concentration of hydrogen ions.

[0030] Based on the stoichiometric relationship of the neutralization reaction, determine the theoretically required amount of calcium hydroxide.

[0031] The effective content, purity, and molar mass of calcium hydroxide in lime slurry are obtained, and the amount of calcium hydroxide required theoretically is converted into the corresponding theoretical volume of lime slurry to be added.

[0032] Multiply the theoretical volume of lime slurry by the preset safety factor to obtain the amount of lime slurry to be added.

[0033] It should be noted that the preset safety factor is a process adjustment factor greater than 1, which is used to make up for the gap between theoretical calculations and actual engineering needs. By introducing this factor, it can be ensured that the calculated basic dosage is sufficient to stably raise the pH value of the wastewater to above the preset neutralization target, thus avoiding substandard effluent due to insufficient dosage.

[0034] The safety factor can be obtained by setting it based on historical operating data and small-scale experiments. Those skilled in the art can determine the appropriate safety factor value according to the characteristics of different wastewaters.

[0035] For example, if a batch of wastewater has a volume of 10 m³ and an initial pH of 1.0, then [H + ] = 0.1 mol / L, nH + =1000mol, requires 500mol of calcium hydroxide (37kg). If the effective content of lime slurry is 90%, the purity is 98%, and the density is 1.2g / mL, then the theoretical volume is about 35L. After multiplying by the safety factor of 1.2, the basic dosage is 42L.

[0036] After obtaining the basic dosage, an initial dosage plan needs to be formulated. Considering that a one-time dosage may easily lead to local over-alkaliness and uneven precipitation, it is preferable to adopt an exponential decay-type staged dosage.

[0037] Furthermore, the initial addition scheme is as follows: the basic addition amount is divided into several consecutive addition stages in chronological order, wherein each addition stage includes a lime slurry addition process and its reaction time.

[0038] The amount of lime slurry added at each stage is distributed according to an exponential decay function, and the sum of the amounts added at each stage is equal to the base amount added.

[0039] It should be noted that in the early stage of the reaction, the hydrogen ion concentration is high and the neutralization driving force is strong. The exponential decay can allocate a higher proportion of the dosage to quickly consume the strong acid. As the pH rises and the acidity decreases, continuing to add a large amount can easily cause a sudden increase in local pH, resulting in precipitation or colloid restabilization. However, the exponential decay can naturally achieve a rapid reduction in the dosage in the later stage, effectively inhibiting local over-alkaliness and passivation.

[0040] Compared to equal or linear distribution, the exponential decay strategy, which concentrates dosage in the early stages and refines it in the later stages, balances response efficiency with endpoint control precision. Furthermore, parameterized distribution can be achieved simply by setting the decay coefficient and the number of stages, resulting in a simple structure and strong engineering adjustability, providing a solid foundation for subsequent dynamic adjustment modules.

[0041] In each dosing stage, the metering pump is controlled to inject the allocated amount of lime slurry into the wastewater in the sedimentation chamber, and a reaction time is set after the dosing is completed. The pH value of the wastewater is obtained at the end of the reaction time as the monitoring time for that stage.

[0042] It should be noted that the reaction time refers to the preset time period after the addition of each lime slurry is completed and waiting for the neutralization reaction to stabilize. It is obtained by observing the change curve of the pH value of the wastewater after adding lime slurry through small-scale experiments. The time elapsed from the end of the addition to when the pH reading enters a stable plateau with fluctuations not exceeding 0.1 within 30 consecutive seconds is usually set to 3 to 15 minutes. Those skilled in the art can make adaptive adjustments to this value according to the actual wastewater characteristics and stirring conditions under this principle.

[0043] In a specific embodiment, the basic dosage is divided into N consecutive dosage stages in chronological order, and the dosage in each stage is distributed in a decreasing manner according to the exponential decay law as follows: .

[0044] where r is the decay factor, with a value range of 0 < r < 1, which is used to control the rate of decrease of the dosage as the stage sequence number i increases, and a typical value is 0.8; is the basic dosage; i is the current dosage stage sequence number, and i = 1, 2,..., N; represents the decay weight with the stage sequence number i as the exponent, is the sum of all stage weights, which is used for normalization to ensure that the total dosage in each stage is strictly equal to the basic dosage, represents the proportion of the dosage in the i-th stage to the basic dosage.

[0045] In the initial stage of the reaction (i = 1), since = 1 is the maximum value, the dosage allocated at the beginning stage is the largest, corresponding to the highest acidity in the wastewater, which can quickly consume hydrogen ions and improve the neutralization efficiency; as the reaction progresses and i increases, decreases exponentially, and the dosage in subsequent stages automatically decreases, effectively avoiding lime waste and increased sludge production caused by local over-alkalinity, while ensuring the overall neutralization process is stable and controllable.

[0046] In each stage, the metering pump is controlled to inject the corresponding amount of lime slurry, a fixed reaction time such as 60 seconds is set, and the pH value of the wastewater is obtained at the end of this reaction time as the monitoring moment for this stage.

[0047] The dynamic dosing control module is used to determine the neutralization performance coefficient of the current stage according to the change in pH before and after dosing in this stage and the amount of lime slurry dosed in this stage during the reaction time after each dosing stage is completed. According to this coefficient, it is judged whether it is necessary to adjust the amount of lime slurry dosed in the next dosing stage, and according to the judgment result and whether the system is in a neutralization stagnation state, a dosing control instruction for the next dosing stage is generated.

[0048] During the phased addition of lime slurry, the dynamic addition control module is used to evaluate the actual impact of the current stage of lime slurry addition on the pH value of wastewater within the reaction time of each addition stage, and calculates the neutralization performance coefficient accordingly as the basis for whether to adjust the addition strategy in the future.

[0049] Considering that changes in pH directly reflect the progress of the neutralization reaction, and that the amount of lime slurry added determines the reactant supply intensity, it is necessary to correlate the two and construct a quantifiable performance index. Based on this, this invention introduces a neutralization performance coefficient to characterize the pH response efficiency induced by the amount of lime added.

[0050] For further details, please refer to [link / reference]. Figure 2 As shown, the method for obtaining the neutralization performance coefficient is as follows: obtain the pH value of the wastewater measured at the end of the reaction time of the current addition stage, and record the cumulative amount of lime slurry added up to this stage.

[0051] Extract the pH value of the wastewater at the end of the reaction time of the previous addition stage and the amount of lime slurry added in that stage, and calculate the pH difference between the two stages as the pH change.

[0052] It should be explained that this difference directly reflects the actual neutralization effect caused by the addition in the previous stage.

[0053] The difference between the system's preset neutralization target pH value and the initial pH value is obtained as the theoretical maximum pH change range. The ratio of the pH change to the theoretical maximum pH change range is used as the normalized pH response value.

[0054] It should be noted that the preset neutralization target pH value is a control endpoint set comprehensively based on the discharge or reuse standards of acid wastewater treatment, the chemical characteristics of the neutralization reaction, and the precipitation effect. It is usually set to 7.5 to 8.5, and preferably 8.0.

[0055] It should be explained that the normalization process is introduced to eliminate the influence of the initial acidity difference between different batches of wastewater on the coefficient calculation, so that the response values ​​are comparable across batches.

[0056] The ratio of the amount of lime slurry added in the previous stage to the basic amount added is used as the normalized addition ratio.

[0057] It should be explained that normalizing the dosage is to map the actual dosage behavior to a relative scale of the theoretical total, so as to avoid the distortion of the coefficient due to different basic dosage sizes.

[0058] When the amount of lime slurry added in the current addition stage is greater than zero and the pH change is greater than or equal to zero, the normalized pH response value is divided by the normalized addition ratio, and the resulting quotient is used as the neutralization performance coefficient for the current stage.

[0059] It should be noted that the neutralization performance coefficient is used to quantitatively assess the actual efficiency of the current lime slurry addition in raising the pH of the wastewater, thereby providing a basis for dynamically adjusting the subsequent addition amount.

[0060] If the coefficient is close to 1, it means that the addition efficiency meets the theoretical expectation. If the coefficient is greater than 1, it means that the efficiency is too high and the addition may be insufficient. If the coefficient is less than 1, it may mean that the addition is excessive or the reaction is hindered, and dynamic adjustment is required.

[0061] However, under certain abnormal operating conditions (such as metering pump failure, pH sensor drift, or reaction lag), the amount of lime slurry added in the previous addition stage may be equal to zero or the pH change may be less than zero. In this case, direct calculation will lead to the distortion of the coefficient or even the error of dividing by zero. Therefore, it is necessary to consider obtaining the coefficient from historical monitoring data.

[0062] If the amount of lime slurry added in the current addition stage is equal to zero or the pH change is less than zero, then the most recent stage that meets the conditions of the lime slurry added in the corresponding addition stage being greater than zero and the pH change being greater than or equal to zero is retrieved from the historical monitoring data, and its corresponding neutralization performance coefficient is taken.

[0063] It should be explained that this condition ensures that the historical coefficients referenced come from a real and valid neutralization process, avoiding the use of anomalous data to interfere with current decision-making.

[0064] If there is no historical monitoring data that meets the conditions, the preset default value will be used as the neutral performance coefficient for the current stage.

[0065] It should be noted that if no historical data meeting the criteria is found after searching, such as during the system's first operation or after a long period of abnormality, the preset default value will be used as the neutralization performance coefficient for the current stage. This default value represents that a unit dosage exactly triggers a unit normalized pH response, and can be used as the initial control baseline.

[0066] The above methods enable a quantitative assessment of the dynamic performance of the neutralization process. Furthermore, by employing normalization, historical backtracking, and default value strategies, the robustness and adaptability of the control logic under various operating conditions are ensured, providing a reliable basis for the precise adjustment of subsequent dosage.

[0067] After obtaining the neutralization performance coefficient, the dynamic dosing control module determines whether the dosing amount needs to be adjusted in the next stage.

[0068] Furthermore, the method for generating the dosing control command for the next dosing stage is as follows: retrieve the most recent dosing stage that simultaneously meets the following conditions from historical monitoring data in reverse chronological order.

[0069] The amount of lime slurry added in this stage is greater than zero, the pH value at the end of this stage is greater than or equal to the pH value at the end of the previous stage, and the neutralization performance coefficient corresponding to this stage is a positive real number.

[0070] It should be explained that the above three conditions are set to ensure that the selected historical stage represents a real, effective and positive neutralization process: the non-zero dosage eliminates interference from no-load operation, the non-decreasing pH eliminates interference from measurement drift or side reactions, and the positive coefficient ensures that it has physical meaning. Only by comparing based on such stages can we accurately determine whether the current efficiency has changed substantially.

[0071] This stage is defined as the pre-effective stage, and its corresponding neutralization performance coefficient is obtained.

[0072] If the neutralization performance coefficient of the current stage is not equal to the neutralization performance coefficient of the previous effective stage, it is determined that the amount of lime slurry added in the next stage needs to be adjusted.

[0073] It should be explained that the logic behind this judgment is as follows: if the neutralization efficiency changes, it means that the current water quality, reaction conditions, or reagent activity have deviated from the initial assumptions. Continuing to use the original scheme will lead to over- or under-dosage, so dynamic correction is necessary.

[0074] Convert the pH values ​​at the end of the current stage and the previous stage into hydrogen ion concentrations, calculate the change in hydrogen ion concentration and the corresponding reaction time, and obtain the rate of change in hydrogen ion concentration as the current reaction activity coefficient.

[0075] It should be explained that the rate of change is calculated using hydrogen ion concentration rather than pH value because pH is a logarithmic scale, and its difference cannot linearly reflect the rate of reactant consumption; while hydrogen ion concentration is a linear quantity, and its rate of change can truly characterize the instantaneous activity of the neutralization reaction, providing a basis for determining whether the reaction is still effective.

[0076] The reaction activity coefficient refers to the rate of decrease in hydrogen ion concentration in wastewater per unit reaction time, characterizing the instantaneous kinetic activity of the current neutralization reaction, and is one of the conditions used to determine whether it is in a neutralization stagnation state.

[0077] The system is considered to be in a neutralization stagnation state when the following conditions are met simultaneously: (a) The current pH value is less than the preset neutralization target pH value.

[0078] (b) The current reactivity coefficient is zero.

[0079] (c) The pH value is the same in N consecutive dosing stages, including the current stage, where N≥2.

[0080] It should be explained that this composite condition is designed to distinguish between normal endpoints and abnormal stagnation: condition (a) excludes cases where the target has been met; condition (b) indicates that no net reaction has occurred; and condition (c) excludes accidental fluctuations. The co-occurrence of these three conditions indicates that the system has fallen into a deadlock where the addition is ineffective but the target has not been met, i.e., a neutralization stagnation state. This may be caused by precipitation, local saturation, or insufficient stirring, which may lead to reaction stagnation and requires special intervention.

[0081] It should be noted that condition (a) uses less than but does not consider equal to or greater than cases in order to ensure that neutralization stagnation is only triggered in abnormal situations where the task is not completed but the response is deadlocked, thus avoiding misjudgment of normal or excessive states.

[0082] If the system is determined to be in a neutral or stagnant state, a trial addition command is generated as the addition control command for the next addition stage.

[0083] The trial addition instruction is as follows: the corresponding current lime slurry addition amount is the product of the addition amount in the previous addition stage and the fixed coefficient γ, where 0 < γ ≤ 0.1.

[0084] It should be noted that the range of the fixed coefficient γ is a reasonable choice based on engineering practice, taking into account sensitivity, safety and economy.

[0085] It should be explained that the trial addition of a very small proportion is to awaken the reaction with minimal reagent cost: if the system does stagnate due to local oversaturation, a small amount of newly added lime slurry may break the equilibrium and restore the reaction; if there is still no response, an alarm can be triggered or manual intervention can be performed to avoid waste or excessive alkalinity caused by blindly adding large amounts.

[0086] Otherwise, substitute the current reactivity coefficient and the current neutralization performance coefficient into the dosage adjustment function to calculate the lime slurry dosage control setpoint for the next dosage stage, and use it as the dosage control command.

[0087] Furthermore, the step of substituting the lime slurry dosage adjustment function to calculate the lime slurry dosage control setting value for the next dosing stage includes: obtaining the lime slurry dosage allocated for the next dosing stage in the initial dosing plan, the neutralization performance coefficient at the end of the reaction time of the current dosing stage, and the reaction activity coefficient of the current dosing stage.

[0088] The ratio of the neutralization performance coefficient in the previous addition stage to the neutralization performance coefficient in the current addition stage is used as the neutralization performance correction factor, and the ratio of the reactivity coefficient in the previous addition stage to the reactivity coefficient in the current addition stage is used as the reactivity correction factor. If the reactivity coefficient in the current addition stage is zero, the reactivity correction factor is set to 1.

[0089] The neutralization performance correction factor and the reactivity correction factor are weighted and fused to obtain the comprehensive correction coefficient.

[0090] It should be noted that the weight allocation of the weighted fusion can be dynamically adjusted according to water quality characteristics or historical batch data, and the default weight allocation is equal weight.

[0091] Multiply the amount of lime slurry allocated for the next addition stage in the initial addition plan by the comprehensive correction coefficient to obtain the control set value of the amount of lime slurry added in the next addition stage.

[0092] It should be explained that this adjustment method is based on the following: the neutralization performance coefficient reflects the efficiency deviation, and the reactivity coefficient reflects the kinetic state. The two together determine the direction and magnitude of the correction.

[0093] If the neutralization performance coefficient decreases and the reactivity coefficient decreases, then the overall correction factor should be greater than 1, and the dosage should be increased appropriately to compensate; otherwise, it should be reduced. When the activity is zero but has not stopped, such as when the addition has just been completed but no reaction has occurred, setting the reactivity correction factor to 1 can avoid misadjustment.

[0094] The sedimentation analysis and adjustment module is used to calculate the sedimentation ratio sequence based on the interface position sequence and corresponding timestamps obtained by the interface detector during the settling stage after the lime slurry is added. The sedimentation rate is obtained through linear regression, and an adjustment factor is generated to correct the basic addition amount of lime slurry for the next batch.

[0095] The introduction of the adjustment factor aims to achieve adaptive optimization across batches, avoiding overdosing or underdosing due to fluctuations in water quality, changes in reagent activity, or differences in operating conditions.

[0096] Furthermore, the method for obtaining the adjustment factor is as follows: by using an interface detector installed on the side wall of the sedimentation chamber, the height value of the mud-water interface from the bottom of the chamber is continuously collected at fixed time intervals to obtain the interface position sequence and corresponding timestamp.

[0097] It should be noted that the fixed time interval is 5 to 30 seconds, preferably 10 seconds. The setting of this time interval needs to take into account both data resolution and system load.

[0098] It should be explained that continuous sampling at fixed time intervals is used to obtain the complete dynamic process of the sedimentation interface evolution over time, avoiding the omission of key sedimentation stages due to sparse sampling; at the same time, the interface detector directly reflects the progress of solid-liquid separation, which is more stable and reliable than indirect indicators such as turbidity or suspended solids concentration.

[0099] The vertical distance from the bottom to the highest liquid level during normal operation within the sedimentation chamber is taken as the effective height, and the sedimentation ratio at each time point is calculated based on the effective height to obtain the sedimentation ratio sequence.

[0100] It should be explained that the effective height is used as a normalization benchmark to eliminate the influence of liquid level fluctuations in different batches on the absolute value of the interface position, so that the sedimentation ratio is comparable between batches; while the sedimentation ratio itself reflects the proportion of settled sludge volume to the total effective volume, which is a direct indicator for measuring sedimentation efficiency.

[0101] The sedimentation rate is obtained by performing linear regression on the sedimentation ratio sequence and the corresponding timestamp.

[0102] It should be explained that linear regression, rather than instantaneous slope, is used to smooth measurement noise and extract the overall trend of the sedimentation process. Under ideal sedimentation conditions, the interface descent rate tends to stabilize, and the linear fitting results can effectively characterize the sedimentation dynamics. If the sedimentation rate is fast, it indicates that the flocs are dense and have good sedimentation properties, which usually means that the neutralization reaction is sufficient and the reagent addition is reasonable. Conversely, it may be due to excessive alkalinity, colloidal instability, or insufficient addition, leading to sedimentation difficulties.

[0103] The ratio of the reference sedimentation rate under historical normal operating conditions to the current sedimentation rate is used as an adjustment factor to correct the basic dosage of the next batch of lime slurry.

[0104] It should be explained that if the current settling rate is lower than the reference value, it indicates that the settling effect has deteriorated. This may be due to insufficient lime slurry addition, resulting in incomplete neutralization and insufficient destabilization of colloids. In this case, the amount of the next batch of base slurry should be appropriately increased to improve flocculation. Conversely, if the settling is too fast, it may be due to excessive addition, resulting in overly dense flocs or a high pH. The dosage can be appropriately reduced to save reagents and avoid scaling. Therefore, the adjustment factor is essentially used to infer the neutralization effect from the settling performance and is used for feedforward correction.

[0105] Furthermore, the precipitation analysis adjustment module also includes the following: storing the adjustment factor and providing it to the initial dosing control module for use at the start of the next batch of processing to correct the basic dosing amount of the next batch of lime slurry.

[0106] It should be explained that by feeding back the precipitation effect to the initial calculation stage of the next batch, closed-loop control is achieved, enabling the system to gradually approach the optimal dosing strategy.

[0107] In addition, to prevent over-adjustment due to random fluctuations, the system terminates the adaptive correction loop when the adjustment factor satisfies |adjustment factor-1|≤ε for M consecutive batches, where M≥2 and ε is the preset convergence tolerance.

[0108] It should be noted that the preset convergence tolerance is 0.02 to 0.1, preferably 0.05, and is used to determine whether the adjustment factor has converged to a stable state. This is obtained by collecting adjustment factor data from multiple stable operating batches during the system debugging phase.

[0109] Example 2

[0110] See Figure 3 As shown, the present invention proposes a method for controlling the treatment and recycling of acid wastewater, including the following steps: S1, obtaining the initial pH value and volume of the acid wastewater to be treated, calculating the basic amount of lime slurry required to neutralize the acidity, and adding the lime slurry to the sedimentation chamber in stages according to the initial addition plan.

[0111] S2. During the reaction time after each addition stage is completed, determine the neutralization performance coefficient of the current stage based on the change in pH before and after the addition of that stage and the amount of lime slurry added in that stage.

[0112] S3. Determine whether the amount of lime slurry added in the next addition stage needs to be adjusted based on the neutralization performance coefficient, and generate the addition control command for the next addition stage based on the judgment result and whether the system is in a neutralization stagnation state.

[0113] S4. During the settling stage after the lime slurry is added, the sedimentation ratio sequence is calculated based on the interface position sequence and corresponding timestamps collected by the interface detector.

[0114] S5. Perform linear regression on the sedimentation ratio sequence to obtain the sedimentation rate, and generate an adjustment factor for correcting the basic dosage of the next batch of lime slurry.

[0115] In summary, this invention first calculates the basic dosage of lime slurry based on the initial pH and volume of the wastewater, and then adds it in stages according to an exponential decay scheme. During the addition process, the subsequent dosage is dynamically adjusted by the neutralization performance coefficient and the reactivity coefficient, and a trial addition strategy is activated when neutralization stagnation is detected. After the addition is completed, the sedimentation rate is dynamically calculated based on the sedimentation interface, and an adjustment factor is generated to optimize the next batch of addition. This invention achieves precise, dynamic, and adaptive lime slurry addition in acid wastewater treatment, effectively improving neutralization efficiency, reducing reagent waste, and optimizing sedimentation effects.

[0116] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0117] Those skilled in the art will recognize that the algorithmic steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0118] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0119] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0120] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 control system for the treatment and recycling of acid production wastewater, characterized in that, include: The initial dosing control module is used to obtain the initial pH value and volume of the acid wastewater to be treated, calculate the basic amount of lime slurry required to neutralize the acidity, and add the lime slurry to the sedimentation chamber in stages according to the initial dosing plan; The dynamic dosing control module is used to determine the neutralization performance coefficient of the current stage based on the change in pH before and after the dosing and the amount of lime slurry added in the current stage within the reaction time after the completion of each dosing stage. Based on the coefficient, it determines whether the amount of lime slurry added in the next dosing stage needs to be adjusted. Based on the judgment result and whether the system is in a neutralization stagnation state, it generates the dosing control command for the next dosing stage. The sedimentation analysis and adjustment module is used to calculate the sedimentation ratio sequence based on the interface position sequence and corresponding timestamps obtained by the interface detector during the settling stage after the lime slurry is added. The sedimentation rate is obtained through linear regression, and an adjustment factor is generated to correct the basic addition amount of lime slurry for the next batch. The method for generating the dosing control command for the next dosing stage is as follows: Retrieve the most recent dosing stage from historical monitoring data in reverse chronological order that simultaneously meets the following conditions: the lime slurry dosage in this stage is greater than zero, the pH value at the end of this stage is greater than or equal to the pH value at the end of the previous stage, and the neutralization performance coefficient corresponding to this stage is a positive real number; determine this stage as the previous effective stage and obtain its corresponding neutralization performance coefficient; if the neutralization performance coefficient of the current stage is not equal to the neutralization performance coefficient of the previous effective stage, then it is determined that the lime slurry dosage for the next stage needs to be adjusted; convert the pH values ​​at the end of the current stage and the previous stage into hydrogen ion concentration, and calculate the change in hydrogen ion concentration and... The rate of change of hydrogen ion concentration is obtained according to the corresponding reaction time and used as the current reaction activity coefficient. The system is determined to be in a neutralization stagnation state when the following conditions are met simultaneously: (a) the current pH value is less than the preset neutralization target pH value; (b) the current reaction activity coefficient is zero; (c) the pH value is equal in N consecutive addition stages including the current stage, where N≥2. If it is determined to be in a neutralization stagnation state, a trial addition command is generated as the addition control command for the next addition stage; otherwise, the current reaction activity coefficient and the current neutralization performance coefficient are substituted into the addition amount adjustment function to calculate the lime slurry addition amount control set value for the next addition stage and used as the addition control command.

2. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The method for obtaining the basic dosage is as follows: The concentration of hydrogen ions in the wastewater is calculated based on the initial pH value of the acid production wastewater. The total amount of hydrogen ions in the wastewater is calculated based on the obtained volume of acid production wastewater and the concentration of hydrogen ions. Based on the stoichiometric relationship of the neutralization reaction, determine the theoretically required amount of calcium hydroxide. The effective content, purity, and molar mass of calcium hydroxide in lime slurry are obtained, and the amount of calcium hydroxide theoretically required is converted into the corresponding theoretical volume of lime slurry to be added. Multiply the theoretical volume of lime slurry by the preset safety factor to obtain the amount of lime slurry to be added.

3. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The initial dosing plan is as follows: The basic dosage is divided into several consecutive addition stages in chronological order, wherein each addition stage includes a lime slurry addition process and its reaction time; The amount of lime slurry added at each stage is distributed according to an exponential decay function, and the sum of the amounts added at each stage is equal to the base amount added. In each dosing stage, the metering pump is controlled to inject the allocated amount of lime slurry into the wastewater in the sedimentation chamber, and a reaction time is set after the dosing is completed. The pH value of the wastewater is obtained at the end of the reaction time as the monitoring time for that stage.

4. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The method for obtaining the neutralization performance coefficient is as follows: Obtain the pH value of the wastewater at the end of the reaction time of the current addition stage, and record the cumulative amount of lime slurry added up to this stage; Extract the pH value of the wastewater at the end of the reaction time of the previous addition stage and the amount of lime slurry added in that stage, and calculate the pH difference between the two stages as the pH change. The difference between the system's preset neutralization target pH value and the initial pH value is obtained as the theoretical maximum pH change range. The ratio of the pH change to the theoretical maximum pH change range is used as the normalized pH response value. The ratio of the amount of lime slurry added in the previous addition stage to the basic addition amount is used as the normalized addition ratio; When the amount of lime slurry added in the current addition stage is greater than zero and the pH change is greater than or equal to zero, the normalized pH response value is divided by the normalized addition ratio, and the quotient is used as the neutralization performance coefficient for the current stage. When the amount of lime slurry added in the current addition stage is equal to zero or the pH change is less than zero, the most recent stage that meets the conditions of the lime slurry added in the corresponding addition stage being greater than zero and the pH change being greater than or equal to zero is retrieved from the historical monitoring data, and its corresponding neutralization performance coefficient is taken. If there is no historical monitoring data that meets the conditions, the preset default value will be used as the neutral performance coefficient for the current stage.

5. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The trial addition instruction is as follows: the corresponding current lime slurry addition amount is the product of the addition amount in the previous addition stage and the fixed coefficient γ, where 0 < γ ≤ 0.

1.

6. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The calculation of the lime slurry dosage control setpoint for the next dosing stage by substituting into the dosage adjustment function includes: Obtain the amount of lime slurry allocated for the next addition stage in the initial addition plan, the neutralization performance coefficient at the end of the reaction time of the current addition stage, and the reactivity coefficient of the current addition stage; The ratio of the neutralization performance coefficient in the previous dosing stage to the neutralization performance coefficient in the current dosing stage is used as the neutralization performance correction factor, and the ratio of the reactivity coefficient in the previous dosing stage to the reactivity coefficient in the current dosing stage is used as the reactivity correction factor. If the reactivity coefficient in the current dosing stage is zero, the reactivity correction factor is set to 1. The neutralization performance correction factor and the reactivity correction factor are weighted and fused to obtain the comprehensive correction coefficient; Multiply the amount of lime slurry allocated for the next addition stage in the initial addition plan by the comprehensive correction coefficient to obtain the control set value of the amount of lime slurry added in the next addition stage.

7. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The method for obtaining the adjustment factor is as follows: An interface detector installed on the side wall of the sedimentation chamber continuously collects the height of the mud-water interface from the bottom of the chamber at fixed time intervals to obtain the interface position sequence and corresponding timestamps. The vertical distance from the bottom to the highest liquid level during normal operation in the sedimentation chamber is taken as the effective height, and the ratio of the interface position to the effective height at each moment is taken as the sedimentation ratio at that moment, thus obtaining the sedimentation ratio sequence. The sedimentation rate was obtained by performing linear regression on the sedimentation ratio sequence and the corresponding timestamp. The ratio of the reference sedimentation rate under historical normal operating conditions to the current sedimentation rate is used as an adjustment factor to correct the basic dosage of the next batch of lime slurry.

8. The acid production wastewater treatment and recycling control system as described in claim 1, characterized in that, The precipitation analysis adjustment module also includes the following: The adjustment factor is stored and called by the initial dosing control module at the start of the next batch of processing to correct the basic dosing amount of lime slurry for the next batch. When the adjustment factor satisfies |adjustment factor-1|≤ε for M consecutive batches, the system terminates the adaptive correction loop, where M≥2 and ε is the preset convergence tolerance.

9. A method for controlling the treatment and recovery of acid production wastewater, comprising the following steps performed by an acid production wastewater treatment and recovery control system as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Obtain the initial pH value and volume of the acid wastewater to be treated, calculate the basic amount of lime slurry required to neutralize the acidity, and add the lime slurry to the sedimentation chamber in stages according to the initial addition plan. S2. During the reaction time after each addition stage is completed, determine the neutralization performance coefficient of the current stage based on the change in pH before and after the addition of the stage and the amount of lime slurry added in the stage. S3. Based on the coefficient, determine whether the amount of lime slurry added in the next addition stage needs to be adjusted, and generate the addition control command for the next addition stage based on the judgment result and whether the system is in a neutral or stagnant state. S4. During the settling stage after the lime slurry is added, the sedimentation ratio sequence is calculated based on the interface position sequence and corresponding timestamps collected by the interface detector. S5. Perform linear regression on the sedimentation ratio sequence to obtain the sedimentation rate, and generate an adjustment factor for correcting the basic dosage of the next batch of lime slurry.

Images