Neutralization reaction system and control method thereof

Abstract

The invention relates to the technical field of chemical production, and discloses a neutralization reaction system and a control method of the neutralization reaction system.The neutralization reaction system comprises a mixer, a PH detection device, a first calculator and a PH controller, a neutralization solution and a regulated solution are subjected to a neutralization reaction in the mixer, and a mixed solution is obtained; a first valve is arranged on a first conveying pipeline from neutralization liquid to a mixer, a pH value controller is in communication connection with a first calculator and the first valve, and the control method comprises the steps that the first calculator obtains a pH detection value, calculates the actual pH value of mixed liquid according to the pH detection value and sends the actual pH value to the pH value controller; and the pH value controller generates the target opening degree of the valve according to the actual pH value and the target pH value of the mixed liquid. According to the method, the PH value is converted into the pH value to serve as a control variable, the adverse effect of the nonlinear characteristic on the control effect when the PH value is close to 7 is effectively overcome, and therefore the control precision and the system stability of the neutralization process are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, specifically to a neutralization reaction system and a control method for the neutralization reaction system. Background Technology

[0002] Neutralization is a common process in the chemical industry, and pH control is a frequent requirement in this field. Poor neutralization can lead to adverse consequences such as equipment corrosion and untreated wastewater. When the target pH value is close to 7, the relationship between pH and neutralizing liquid flow rate exhibits strong non-linearity near pH=7. In this situation, the conventional method of controlling the pH cascade neutralizing liquid flow rate after neutralization may not meet the control requirements, and even small fluctuations in the neutralizing liquid flow rate can significantly impact the effectiveness of pH control after neutralization. Summary of the Invention

[0003] In view of this, the present invention provides a neutralization reaction system and a control method for the neutralization reaction system to solve the problem that when the target value of pH control is close to 7, the ordinary control method of neutralizing liquid flow rate after neutralization cannot meet the control requirements.

[0004] In a first aspect, the present invention provides a control method for a neutralization reaction system. The neutralization reaction system includes a mixer, a pH detection device, a first calculator, and an acid-base controller. A neutralizing liquid and a liquid to be adjusted undergo a neutralization reaction in the mixer to obtain a mixed liquid. The pH detection device is communicatively connected to the first calculator and is used to detect the pH value of the mixed liquid. A first valve is provided on a first delivery pipeline from the neutralizing liquid to the mixer. The acid-base controller is communicatively connected to the first calculator and the first valve. The control method includes the following steps: the first calculator is used to acquire the pH detection value detected by the pH detection device, calculate the actual acid-base of the mixed liquid based on the pH detection value, and send the actual acid-base to the acid-base controller; the acid-base controller generates a target valve opening degree based on the actual acid-base of the mixed liquid and the target acid-base of the mixed liquid, and sends the target valve opening degree to the first valve.

[0005] The neutralization reaction system and its control method provided by this invention effectively overcome the adverse effects of the nonlinear characteristics of pH near 7 on the control effect by converting pH value into acidity / alkalinity as a control variable, thereby significantly improving the control accuracy and system stability of the neutralization process. This method can more accurately reflect the H+ in the solution. + or OH -By accurately controlling the actual concentration changes, the system reduces malfunctions caused by minor pH fluctuations, thus enhancing its anti-interference capabilities. Simultaneously, precise control of the neutralizing liquid flow rate improves neutralization efficiency, reduces energy and material consumption, and avoids resource waste and secondary pollution. Furthermore, this method is highly adaptable and can be widely applied in wastewater treatment, chemical production, and other fields. It is easily integrated with existing industrial control systems, possessing significant potential for automation and intelligent upgrades. It helps ensure equipment safety and extend service life, demonstrating substantial technical advantages and application value.

[0006] In one optional embodiment, the neutralization reaction system further includes a valve position controller, and a second valve is provided on the second delivery pipeline from the neutralized liquid to the mixer; wherein the valve position controller is communicatively connected to the pH controller, and after generating a target valve opening degree based on the actual pH and target pH of the mixture, the system further includes: the pH controller sending the target valve opening degree to the valve position controller; the valve position controller determining whether the target valve opening degree falls within a preset valve opening degree range; when the target valve opening degree does not fall within the valve opening degree range, generating an adjustment ratio based on the target valve opening degree and the valve opening degree range, so as to adjust the opening degree of the second valve according to the adjustment ratio.

[0007] In other words, the neutralization reaction system incorporates a valve position controller and a second valve installed on the second delivery pipeline, forming a parallel structure of a main control valve (i.e., the second valve) and an auxiliary valve (i.e., the first valve) with the first valve. This, combined with a pH controller, implements a control strategy that integrates variable ratio control and valve position control. This composite control method not only improves the accuracy and flexibility of neutralizing liquid flow regulation but also effectively avoids control instability or response hysteresis that may occur with a single valve at its extreme opening, enhancing the system's robustness and adaptability. Simultaneously, the coordinated operation of the main control valve and the auxiliary valve better copes with flow disturbances and load changes, significantly reducing the impact of neutralizing liquid flow fluctuations on pH control, thereby further ensuring the stability, continuity, and control accuracy of the neutralization process, demonstrating significant engineering application value.

[0008] In one optional embodiment, the neutralization reaction system further includes a variable ratio controller, a flow detection device on a third delivery pipeline of the liquid to be adjusted to the mixer, and a flow controller on a second delivery pipeline. The variable ratio controller is communicatively connected to the valve position controller, the flow detection device, and the flow controller. After generating an adjustment ratio based on the target valve opening and the valve opening range, the system further includes the following steps: the variable ratio controller acquires the actual flow rate of the liquid to be adjusted detected by the flow detection device; generates a set value for the flow controller based on the adjustment ratio and the actual flow rate of the liquid to be adjusted; and sends the set value of the flow controller to the flow controller so that the flow controller adjusts the opening of the second valve according to the set value.

[0009] This invention further incorporates a variable ratio controller, a flow detection device, and a flow controller to form a more intelligent and flexible control closed loop. The variable ratio controller acquires the actual flow rate of the liquid being adjusted in real time, and combined with the adjustment ratio generated by the valve position controller, dynamically calculates the setpoint of the flow controller, thereby precisely adjusting the opening of the second valve. This control strategy achieves dynamic flow ratio control between the neutralizing liquid and the liquid being adjusted, effectively addressing the impact of fluctuations in the flow rate of the liquid being adjusted on the neutralization process, and improving the system's response speed and control accuracy. Simultaneously, the closed-loop adjustment of the second valve by the flow controller enhances the stability and adaptability of the neutralizing liquid flow control, avoids pH fluctuations caused by flow disturbances, further ensures the smooth operation of the neutralization reaction process, and exhibits good robustness and engineering practicality.

[0010] In one optional implementation, generating the set value of the flow controller based on the adjustment ratio and the actual flow rate of the liquid being adjusted includes multiplying the adjustment ratio and the actual flow rate of the liquid being adjusted to obtain the set value of the flow controller.

[0011] This invention generates the set value of the flow controller by multiplying the adjustment ratio by the actual flow rate of the liquid being adjusted, thereby achieving dynamic proportional matching between the flow rate of the neutralizing liquid and the flow rate of the liquid being adjusted. This further improves the response speed and control accuracy of the neutralization reaction system and helps maintain the stability and continuity of the neutralization process.

[0012] In one optional implementation, after sending the set value of the flow controller to the flow controller, the method further includes: the flow controller acquiring the actual value of the neutralizing liquid flow rate in the second delivery pipeline; and the flow controller performing PID adjustment on the opening degree of the second valve based on the set value and the actual value of the neutralizing liquid flow rate.

[0013] This invention uses a flow controller to collect the actual flow rate of the neutralizing liquid in the second delivery pipeline and combines it with a set value for PID adjustment, achieving closed-loop precise control of the second valve opening. This control method further improves the stability and response accuracy of the neutralizing liquid flow rate adjustment, effectively reduces pH control deviation caused by flow fluctuations, and ensures the smooth operation of the neutralization process.

[0014] In one optional embodiment, the neutralization reaction system further includes an input device and a second calculator. The input device is communicatively connected to the pH controller via the second calculator. Before generating the target valve opening based on the actual pH of the mixture and the target pH of the mixture, the system further includes: the input device for acquiring the input target pH value and sending the target pH value to the second calculator; and the second calculator for calculating the target pH of the mixture based on the target pH value.

[0015] This invention, by incorporating an input device and a second calculator, achieves automatic conversion from target pH value to target acidity / alkalinity, improving the ease of system operation and control precision. Users only need to input the desired pH value, and the system can automatically calculate the corresponding acidity / alkalinity control target, providing an accurate basis for subsequent valve opening adjustments and further enhancing the intelligence and flexibility of the neutralization reaction system.

[0016] In one optional implementation, a first calculator is used to input the pH detection value into a preset acidity / alkalinity calculation formula to obtain the actual acidity / alkalinity of the mixture; a second calculator is used to input the target pH value into the acidity / alkalinity calculation formula to obtain the target acidity / alkalinity of the mixture.

[0017] This invention uses a first calculator and a second calculator to substitute the actual detected pH value and the target pH value into a preset acidity / alkalinity calculation formula, accurately calculating the actual and target acidity / alkalinity of the mixture, thus ensuring the calculation accuracy and consistency of the control system. This acidity / alkalinity conversion method based on a unified formula improves the accuracy of the system's description of the neutralization reaction process, providing reliable data support for achieving high-precision and stable neutralization control.

[0018] In one optional embodiment, the pH controller generates the target valve opening based on the actual pH of the mixture and the target pH of the mixture by performing PID control on the target valve opening based on the actual pH of the mixture and the target pH of the mixture.

[0019] In this invention, the pH controller employs a PID control method, generating the target valve opening based on the deviation between the actual pH of the mixture and the target pH, thus achieving precise closed-loop control of the neutralization liquid flow rate. This method effectively improves the system's response speed and adjustment accuracy to pH changes, enhances the stability and anti-interference capability of the control system, and further improves the control quality and operational reliability of the neutralization reaction process.

[0020] In a second aspect, the present invention also provides a neutralization reaction system and a control method for performing the neutralization reaction system of any one of the first aspects. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1This is a flowchart of the reaction system control method according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of an example of the reaction system in an embodiment of the present invention;

[0024] Figure 3 This is a flowchart of another neutralization reaction system control method according to an embodiment of the present invention;

[0025] Figure 4 This is a flowchart of a neutralization reaction system control method according to an embodiment of the present invention;

[0026] Figure 5 This is a flowchart of another neutralization reaction system control method according to an embodiment of the present invention;

[0027] Among them, 1. pH detection device; 2. First calculator; 3. pH controller; 4. First valve; 5. Valve position controller; 6. Second valve; 7. Variable ratio controller; 8. First flow detection device; 9. First flow controller; 10. Second calculator; 11. Input device; 12. Control valve for the liquid being regulated; 13. Second flow detection device; 14. Second flow controller. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0029] According to an embodiment of the present invention, a control method embodiment for a neutralization reaction system is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0030] This embodiment provides a control method for a neutralization reaction system, which can be used in a neutralization reaction system. The neutralization reaction system includes a mixer, a pH detection device 1, a first calculator 2, and an acid-base controller 3. The neutralizing liquid and the liquid to be adjusted undergo a neutralization reaction in the mixer to obtain a mixed liquid. The pH detection device 1 is communicatively connected to the first calculator 2 and is used to detect the pH value of the mixed liquid. A first valve 4 is provided on the first delivery pipeline from the neutralizing liquid to the mixer. The acid-base controller 3 is communicatively connected to the first calculator 2 and the first valve 4. In this embodiment, the first valve 4 can also be referred to as an auxiliary valve.

[0031] Figure 1 This is a flowchart of the reaction system control method according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of an embodiment of the present invention and an example of a reaction system, as shown below. Figure 1 and Figure 2 As shown, the process includes the following steps:

[0032] Step S101: The first calculator 2 is used to obtain the pH value detected by the pH detection device 1, calculate the actual acidity or alkalinity of the mixture based on the pH value, and send the actual acidity or alkalinity to the acidity or alkalinity controller 3.

[0033] Specifically, the first calculator 2 is used to input the pH detection value into the preset acidity and alkalinity calculation formula to obtain the actual acidity and alkalinity of the mixture.

[0034] For example, the formula for calculating pH is:

[0035] K = 10 PH-14 -10 -PH

[0036] In the pH calculation formula, K represents pH.

[0037] Step S102: The pH controller 3 generates the target valve opening degree based on the actual pH of the mixture and the target pH of the mixture, and sends the target valve opening degree to the first valve 4.

[0038] The valve opening range is determined based on the performance of the first valve 4. Recommended relative stroke or opening range of the regulating valve can be obtained from the valve supplier, and the final determined valve opening range should be within the recommended relative stroke or opening range of the regulating valve.

[0039] The neutralization reaction system and its control method provided in this embodiment effectively overcome the adverse effects of the nonlinear characteristics of pH near 7 on the control effect by converting pH value into acidity / alkalinity as a control variable, thereby significantly improving the control accuracy and system stability of the neutralization process. This method can more accurately reflect the H+ in the solution. + or OH - By accurately controlling the actual concentration changes, the system reduces malfunctions caused by minor pH fluctuations, thus enhancing its anti-interference capabilities. Simultaneously, precise control of the neutralizing liquid flow rate improves neutralization efficiency, reduces energy and material consumption, and avoids resource waste and secondary pollution. Furthermore, this method is highly adaptable and can be widely applied in wastewater treatment, chemical production, and other fields. It is easily integrated with existing industrial control systems, possessing significant potential for automation and intelligent upgrades. It helps ensure equipment safety and extend service life, demonstrating substantial technical advantages and application value.

[0040] This embodiment provides a control method for a neutralization reaction system, which can be used in a neutralization reaction system. The neutralization reaction system includes a mixer, a pH detection device 1, a first calculator 2, an acidity / alkalinity controller 3, and a valve position controller 5. The neutralizing liquid and the liquid to be adjusted undergo a neutralization reaction in the mixer to obtain a mixed liquid. The pH detection device 1 is communicatively connected to the first calculator 2 and is used to detect the pH value of the mixed liquid. A first valve 4 is provided on a first delivery pipeline from the neutralizing liquid to the mixer, and a second valve 6 is provided on a second delivery pipeline from the neutralizing liquid to the mixer. The acidity / alkalinity controller 3 is communicatively connected to the first calculator 2, the valve position controller 5, and the first valve 4. In this embodiment, the first valve 4 can also be called an auxiliary valve, and the second valve 6 can also be called a main control valve.

[0041] Figure 3 This is a flowchart of another neutralization reaction system control method according to an embodiment of the present invention, such as... Figure 3 and Figure 2 As shown, the process includes the following steps:

[0042] Step S301: The first calculator 2 is used to obtain the pH value detected by the pH detection device 1, calculate the actual acidity or alkalinity of the mixture based on the pH value, and send the actual acidity or alkalinity to the acidity or alkalinity controller 3.

[0043] Step S302: The pH controller 3 generates the target valve opening degree based on the actual pH of the mixture and the target pH of the mixture, and sends the target valve opening degree to the first valve 4 and the valve position controller 5.

[0044] Step S303: Valve position controller 5 determines whether the target valve opening is within the preset valve opening range; when the target valve opening is not within the valve opening range, it generates an adjustment ratio based on the target valve opening and the valve opening range, and adjusts the opening of the second valve 6 according to the adjustment ratio.

[0045] The flow capacity of the auxiliary valve should be 1 / 10 of that of the main control valve.

[0046] This embodiment introduces a valve position controller 5 and a second valve 6 installed on the second delivery pipeline into the neutralization reaction system. Together with the first valve 4, they form a parallel structure of a main control valve (i.e., the second valve 6) and an auxiliary valve (i.e., the first valve 4). Combined with a pH controller 3, it implements a control strategy that integrates variable ratio control and valve position control. This design uses the valve position controller 5 to compare the target valve opening with the preset valve opening range to determine whether the current control command exceeds the valve's effective adjustment capability. When the target opening exceeds the set range, the system can generate an adjustment ratio based on the deviation and dynamically adjust the opening of the second valve 6, thereby achieving optimized flow distribution control. This composite control method not only improves the accuracy and flexibility of neutralization liquid flow regulation but also effectively avoids control instability or response lag that may occur with a single valve at its extreme opening, enhancing the system's robustness and adaptability. Simultaneously, the coordinated operation of the main control valve and the auxiliary valve can better cope with flow disturbances and load changes, significantly reducing the impact of neutralization liquid flow fluctuations on pH control, thereby further ensuring the stability, continuity, and control accuracy of the neutralization process, demonstrating significant engineering application value.

[0047] This embodiment provides a control method for a neutralization reaction system, which can be used in a neutralization reaction system. The neutralization reaction system includes a mixer, a pH detection device 1, a first calculator 2, an acidity / alkalinity controller 3, a valve position controller 5, and a ratio controller 7. The neutralizing liquid and the liquid to be adjusted undergo a neutralization reaction in the mixer to obtain a mixed liquid. The pH detection device 1 is communicatively connected to the first calculator 2 and is used to detect the pH value of the mixed liquid. A first valve 4 is provided on the first delivery pipeline from the neutralizing liquid to the mixer. A second valve 6 and a first flow controller 9 are provided on the second delivery pipeline from the neutralizing liquid to the mixer. A first flow detection device 8 is provided on the third delivery pipeline from the liquid to the mixer. The acidity / alkalinity controller 3 is communicatively connected to the first calculator 2, the valve position controller 5, and the first valve 4. The ratio controller 7 is communicatively connected to the valve position controller 5, the first flow detection device 8, and the first flow controller 9.

[0048] Figure 4 This is a flowchart of a neutralization reaction system control method according to an embodiment of the present invention, such as... Figure 4 and Figure 2 As shown, the process includes the following steps:

[0049] Step S401: The first calculator 2 is used to obtain the pH value detected by the pH detection device 1, calculate the actual acidity or alkalinity of the mixture based on the pH value, and send the actual acidity or alkalinity to the acidity or alkalinity controller 3.

[0050] Step S402: The pH controller 3 generates the target valve opening degree based on the actual pH of the mixture and the target pH of the mixture, and sends the target valve opening degree to the first valve 4 and the valve position controller 5.

[0051] Step S403: Valve position controller 5 determines whether the target valve opening is within the preset valve opening range; when the target valve opening is not within the valve opening range, it generates an adjustment ratio based on the target valve opening and the valve opening range, and sends the adjustment ratio to variable ratio controller 7.

[0052] Step S404: The variable ratio controller 7 acquires the actual flow rate of the liquid being regulated detected by the first flow detection device 8; generates the set value of the first flow controller 9 based on the regulation ratio and the actual flow rate of the liquid being regulated, and sends the set value of the first flow controller 9 to the first flow controller 9.

[0053] Specifically, generating the setpoint of the first flow controller 9 based on the adjustment ratio and the actual flow rate of the liquid being adjusted includes multiplying the adjustment ratio and the actual flow rate of the liquid being adjusted to obtain the setpoint of the first flow controller 9. That is, the setpoint of the first flow controller 9 can be calculated using the formula d = b × c, where d represents the setpoint of the first flow controller 9, b represents the actual flow rate of the liquid being adjusted, and c represents the adjustment ratio, which is calculated by the valve position controller 5.

[0054] This achieves dynamic proportional matching between the neutralizing liquid flow rate and the controlled liquid flow rate, further improving the response speed and control accuracy of the neutralization reaction system, and helping to maintain the stability and continuity of the neutralization process.

[0055] Step S405: The first flow controller 9 obtains the actual value of the flow rate of the neutralizing liquid in the second delivery pipeline.

[0056] Step S406: The first flow controller 9 performs PID adjustment on the opening of the second valve 6 according to the set value and the actual value of the neutral liquid flow rate.

[0057] The control method for the neutralization reaction system provided in this embodiment further incorporates a variable ratio controller 7, a first flow detection device 8, and a first flow controller 9, forming a more intelligent and flexible control closed loop. The variable ratio controller 7 acquires the actual flow rate of the liquid being adjusted in real time, and, combined with the adjustment ratio generated by the valve position controller 5, dynamically calculates the setpoint of the first flow controller 9, thereby precisely adjusting the opening of the second valve 6. This control strategy achieves dynamic flow ratio control between the neutralizing liquid and the liquid being adjusted, effectively addressing the impact of fluctuations in the flow rate of the liquid being adjusted on the neutralization process, and improving the system's response speed and control accuracy. Simultaneously, the closed-loop adjustment of the second valve 6 by the first flow controller 9 enhances the stability and adaptability of the neutralizing liquid flow control, avoids pH fluctuations caused by flow disturbances, further ensures the smooth operation of the neutralization reaction process, and exhibits good robustness and engineering practicality.

[0058] This embodiment provides a control method for a neutralization reaction system, which can be used in a neutralization reaction system. The neutralization reaction system includes a mixer, a pH detection device 1, a first calculator 2, an acid-base controller 3, a valve position controller 5, a ratio controller 7, an input device 11, and a second calculator 10. The neutralizing liquid and the liquid to be adjusted undergo a neutralization reaction in the mixer to obtain a mixture. The pH detection device 1 is communicatively connected to the first calculator 2 and is used to detect the pH value of the mixture. A first valve 4 is provided on the first delivery pipeline from the neutralizing liquid to the mixer. A second valve 6 and a first flow controller 9 are provided on the second delivery pipeline from the neutralizing liquid to the mixer. A first flow detection device 8 is provided on the third delivery pipeline from the liquid to the mixer. The acid-base controller 3 is communicatively connected to the first calculator 2, the valve position controller 5, and the first valve 4. The ratio controller 7 is communicatively connected to the valve position controller 5, the first flow detection device 8, and the first flow controller 9. The input device 11 is communicatively connected to the acid-base controller 3 through the second calculator 10. Figure 2 As shown, the reaction system also includes a second flow detection device 13, which is used to detect the flow rate of the neutralizing liquid in the second delivery pipeline.

[0059] Figure 5 This is a flowchart of another neutralization reaction system control method according to an embodiment of the present invention, such as... Figure 4 and Figure 2 As shown, the process includes the following steps:

[0060] Step S501: Input device 11 is used to obtain the input pH target value and send the pH target value to the second calculator 10.

[0061] Step S502: The second calculator 10 is used to calculate the target pH of the mixture based on the target pH value.

[0062] Step S503: The first calculator 2 is used to obtain the pH value detected by the pH detection device 1, calculate the actual acidity or alkalinity of the mixture based on the pH value, and send the actual acidity or alkalinity to the acidity or alkalinity controller 3.

[0063] Step S504: The pH controller 3 generates the target valve opening degree based on the actual pH of the mixture and the target pH of the mixture, and sends the target valve opening degree to the first valve 4 and the valve position controller 5.

[0064] Step S505: Valve position controller 5 determines whether the target valve opening is within the preset valve opening range; when the target valve opening is not within the valve opening range, it generates an adjustment ratio based on the target valve opening and the valve opening range, and sends the adjustment ratio to variable ratio controller 7.

[0065] Step S506: The variable ratio controller 7 acquires the actual flow rate of the liquid being regulated detected by the first flow detection device 8; generates the set value of the first flow controller 9 based on the regulation ratio and the actual flow rate of the liquid being regulated, and sends the set value of the first flow controller 9 to the first flow controller 9.

[0066] Step S507: The first flow controller 9 obtains the actual value of the flow rate of the neutralizing liquid in the second delivery pipeline.

[0067] Step S508: The first flow controller 9 performs PID adjustment on the opening of the second valve 6 according to the set value and the actual value of the neutral liquid flow rate.

[0068] This invention, by incorporating an input device and a second calculator 10, achieves automatic conversion from the target pH value to the target acidity / alkalinity, improving the ease of system operation and control accuracy. Users only need to input the desired pH value, and the system can automatically calculate the corresponding acidity / alkalinity control target, providing an accurate basis for subsequent valve opening adjustments and further enhancing the intelligence and flexibility of the neutralization reaction system.

[0069] like Figure 2 As shown, the reaction system also includes a controlled liquid control valve 12 and a second flow controller 14. The flow rate of the controlled liquid entering the mixer is controlled by the second flow controller 14 and the controlled liquid control valve 12.

[0070] The present invention also provides a neutralization reaction system that performs the control method of the neutralization reaction system described above.

[0071] As can be seen from the above, the new neutralization reaction system of the present invention has the following three basic functions.

[0072] Basic Function 1: Convert pH value into acidity / alkalinity, and use acidity / alkalinity as a variable to control the feed flow rate of the neutralization solution. Specifically, pH detection device 1 measures the pH value after neutralization, and the first calculator 2 converts the pH value into acidity / alkalinity before sending it to the acidity / alkalinity controller 3 as the measured value; the input device 11 inputs the set pH value, which is converted into acidity / alkalinity by the second calculator 10 and then input to the acidity / alkalinity controller 3 as the set value.

[0073] Basic Function 2: The design of the parallel connection of the main control valve and auxiliary valve on the neutralizing liquid feed pipeline and the valve position control method of the auxiliary valve, so as to finely regulate the neutralizing liquid feed flow rate.

[0074] Specifically, the auxiliary valve should meet the following conditions: ① The flow capacity of the auxiliary valve should be 1 / 10 of the flow capacity of the main control valve; ② The opening degree of the auxiliary valve is controlled by the pH controller 3, and the output of the pH controller 3 is sent to the valve position controller 5 as the measured value of the valve position controller 5. The set value of the valve position controller 5 is 50%, and the output of the valve position controller 5 is sent to the variable ratio controller 7, which in turn controls the valve position of the main control valve. The purpose of the valve position controller 5 is to keep the more precise auxiliary valve within the adjustable range of the valve by controlling the opening degree of the main control valve, thereby achieving fine adjustment of the neutralization liquid flow rate.

[0075] The main control valve should meet the following conditions: ① The main control valve is controlled by the first flow controller 9, and the set value of the first flow controller 9 is calculated by the variable ratio controller 7.

[0076] Basic Function 3: Variable ratio control of neutralizing solution and controlled solution, improving the control effect of pH control.

[0077] Specifically, the variable ratio controller 7 receives the output signal of the valve position controller 5 and the flow measurement signal of the liquid to be adjusted detected by the first flow detection device 8, calculates the amount of neutralized liquid to be added under the current operating conditions, and sends it to the pipeline where the main control valve is located as the set value of the first flow controller 9.

[0078] The neutralization reaction system provided by this invention converts pH value into acidity / alkalinity and uses acidity / alkalinity as a variable to control the flow rate of the neutralizing liquid. This can solve the problem of the influence of nonlinearity of the neutralization curve on the control effect. At the same time, by using the design of parallel connection of main control valve and auxiliary valve on the neutralizing liquid pipeline, as well as variable ratio control and valve position control, precise control of the neutralizing liquid flow rate can be achieved, reducing the impact of the neutralizing liquid flow rate on the pH control effect.

[0079] For example, alkaline wastewater from a certain production process needs to be neutralized with 98% sulfuric acid. After being mixed with sulfuric acid in a mixer, the alkaline wastewater enters a buffer tank. The process target is that the pH of the neutralized wastewater is 5.5. If the neutralization process is poorly controlled, wastewater with an unqualified pH may enter the downstream wastewater treatment system, causing adverse effects on the wastewater treatment system.

[0080] The original control method was to control the pH of the neutralized wastewater by setting a first flow controller 9 on the neutralized liquid feed pipeline and the controlled liquid feed pipeline to control the feed valves. A pH online detection controller was set after the feed mixer. The pH online detection controller was used to cascade control the flow of the neutralized liquid and control the valves on the neutralized liquid feed pipeline.

[0081] After using the linearized control improvement method for the pH-sensitive region provided by this invention, the following modifications are made to the original control logic:

[0082] ① A linearization calculator is added to the set value and measured value of the pH online detection controller at the outlet of the feed mixer. The pH value is converted into acidity or alkalinity using the linearization calculator and then input for control calculation.

[0083] ② The original control valve on the neutralizing liquid feed line is used as the main control valve. A parallel line is added to the neutralizing liquid line, and an auxiliary valve is added to the parallel line. The flow capacity of the auxiliary valve is 1 / 10 of that of the main control valve.

[0084] ③ The cascade control of the neutralizing liquid flow rate by the pH online detection controller at the feed mixer outlet is cancelled. The auxiliary valve position is controlled by the pH online detection controller at the mixer outlet. At the same time, a valve position controller 5 and a variable ratio controller 7 are added. The output value of the variable ratio controller 7 is sent to the first flow controller 9 of the neutralizing liquid feed pipeline as the set value of the first flow controller 9.

[0085] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for controlling a neutralization reaction system, characterized in that, The neutralization reaction system includes a mixer, a pH detection device (1), a first calculator (2), and an acid-base controller (3). The neutralizing liquid and the liquid to be adjusted undergo a neutralization reaction in the mixer to obtain a mixture. The pH detection device (1) is communicatively connected to the first calculator (2) and is used to detect the pH value of the mixture. A first valve (4) is provided on the first delivery pipeline from the neutralizing liquid to the mixer. The acid-base controller (3) is communicatively connected to the first calculator (2) and the first valve (4). The control method includes: The first calculator (2) is used to obtain the pH detection value detected by the pH detection device (1), calculate the actual acidity or alkalinity of the mixture based on the pH detection value, and send the actual acidity or alkalinity to the acidity or alkalinity controller (3); The pH controller (3) generates a target valve opening degree based on the actual pH of the mixture and the target pH of the mixture, and sends the target valve opening degree to the first valve (4).

2. The method according to claim 1, characterized in that, The neutralization reaction system further includes a valve position controller (5), and a second valve (6) is provided on the second delivery pipeline from the neutralized liquid to the mixer; wherein the valve position controller (5) is communicatively connected to the pH controller (3), and after generating a target valve opening degree based on the actual pH of the mixture and the target pH of the mixture, it further includes: The pH controller (3) sends the target valve opening to the valve position controller (5); The valve position controller (5) determines whether the target valve opening is within a preset valve opening range; when the target valve opening is not within the valve opening range, it generates an adjustment ratio based on the target valve opening and the valve opening range, and adjusts the opening of the second valve (6) according to the adjustment ratio.

3. The method according to claim 1, characterized in that, The valve opening range is determined based on the performance of the first valve (4).

4. The method according to claim 2, characterized in that, The neutralization reaction system further includes a variable ratio controller (7), a first flow detection device (8) is provided on the third delivery pipeline from the liquid to the mixer, and a first flow controller (9) is provided on the second delivery pipeline. The variable ratio controller (7) is communicatively connected to the valve position controller (5), the first flow detection device (8), and the first flow controller (9). After generating the adjustment ratio based on the target valve opening and the valve opening range, the system further includes: The variable ratio controller (7) acquires the actual flow rate of the liquid being regulated detected by the first flow detection device (8); generates a set value for the first flow controller (9) based on the adjustment ratio and the actual flow rate of the liquid being regulated, and sends the set value of the first flow controller (9) to the first flow controller (9) so that the first flow controller (9) adjusts the opening of the second valve (6) according to the set value.

5. The method according to claim 4, characterized in that, The process of generating the set value of the first flow controller (9) based on the adjustment ratio and the actual flow rate of the liquid being adjusted includes: The set value of the first flow controller (9) is obtained by multiplying the adjustment ratio and the actual flow rate of the liquid being adjusted.

6. The method according to claim 4, characterized in that, After sending the set value of the first flow controller (9) to the first flow controller (9), the method further includes: The first flow controller (9) obtains the actual value of the flow rate of the neutralizing liquid in the second delivery pipeline; The first flow controller (9) performs PID adjustment on the opening of the second valve (6) according to the set value and the actual value of the neutral liquid flow rate.

7. The method according to claim 1, characterized in that, The neutralization reaction system further includes an input device (11) and a second calculator (10). The input device (11) is communicatively connected to the pH controller (3) via the second calculator (10). Before generating the target valve opening based on the actual pH of the mixture and the target pH of the mixture, the system further includes: The input device (11) is used to acquire the input pH target value and send the pH target value to the second calculator (10); The second calculator (10) is used to calculate the target pH of the mixture based on the target pH value.

8. The method according to claim 7, characterized in that, The first calculator (2) is used to input the pH detection value into a preset acidity / alkalinity calculation formula to obtain the actual acidity / alkalinity of the mixture; The second calculator (10) is used to input the target pH value into the pH calculation formula to obtain the target pH of the mixture.

9. The method according to claim 1, characterized in that, The pH controller (3) generates a target valve opening based on the actual pH of the mixture and the target pH of the mixture, including: The pH controller (3) performs PID adjustment on the target opening of the valve based on the actual pH of the mixture and the target pH of the mixture.

10. A neutralization reaction system, characterized in that, A method for controlling the neutralization reaction system according to any one of claims 1 to 9.

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