An intelligent control method and system for biochemical treatment of PVC centrifugal mother liquor

Abstract

The present invention discloses an intelligent control method and system for biochemical treatment of PVC centrifugal mother liquor. The internal temperature of the buffer tank is controlled according to the ambient temperature and the incoming liquid temperature of the buffer tank; the target pH value of the buffer tank is obtained, the pH difference between the target pH value of the buffer tank and the actually measured pH value of the buffer tank is calculated, and the pH difference is input into an advanced control model, and the operation result of the pH difference is output to a splitting module, and the acid addition regulating valve or the alkali addition regulating valve is judged to be opened according to the operation result of the pH difference; the target COD value of the buffer tank is obtained, the COD difference between the target COD value of the buffer tank and the actually measured COD value of the buffer tank is calculated, and the COD difference is input into the advanced control model. The advanced control model outputs the operation result of the COD difference to the COD coordination module, and the COD coordination module adjusts the water replenishing regulating valve or increases the frequency conversion of the nutrient agent auger or does not perform any adjustment according to the operation result of the COD difference.

Description

Technical Field

[0001] This application relates to the technical field of intelligent control for the biochemical treatment of PVC centrifugal mother liquor, and particularly to an intelligent control method and system for the biochemical treatment of PVC centrifugal mother liquor. Background Art

[0002] The biochemical treatment of PVC centrifugal mother liquor is a key part of the entire sewage treatment system. As Figure 2 shown, the amount of PVC centrifugal mother liquor is relatively large, and 2.5 - 4.0 m3 of wastewater can be produced for every 1 ton of polyvinyl chloride produced. The organic matter concentration in the wastewater is relatively low, and the COD is generally between 150 - 400 mg / L. The main pollutants include residual polyethylene monomers from the polymerization reaction, various polymerization aids (such as dispersants, initiators, terminators, wall coating agents, etc.) and their reaction and decay products. Approximately 85% of the COD in the wastewater is low-boiling organic matter mainly composed of fatty alcohols and aromatic alcohols, and about 13% of the COD is high-boiling substances that do not volatilize at room temperature, mainly composed of alkanes, PVA80, phthalate esters, and sodium salts. The polymerization water is deionized water, and there is no link in the polymerization process to increase the water hardness and salt content. Therefore, the centrifugal mother liquor wastewater has low hardness, low conductivity, high water quality, and great potential utilization value. The biochemical treatment technology is widely used in the industry. After steps such as anaerobic treatment, aerobic treatment, advanced oxidation, precipitation, and filtration, the effluent can meet the circulating water or reclaimed water reuse standards, with relatively stable water quality, simple maintenance, and long service life.

[0003] Pretreatment is carried out at the front end of the centrifugal mother liquor wastewater to reduce the impact on the biochemical system. The centrifugal mother liquor wastewater, stripping wastewater, and domestic sewage are mixed after their respective pretreatments and then pass through the primary sedimentation tank and the biochemical reaction tank in sequence. In the two-stage biochemical reaction tank, most of the organic matter in the wastewater is degraded after hydrolysis acidification reaction and biofilm treatment. The COD at the end of the biochemical treatment can be stabilized within 40 mg / L. However, since the regulation of the sewage treatment system is in the mode of manual remote operation, it cannot respond to system disturbances in a timely, accurate, and consistent manner in real time. The establishment of the balance of the biochemical system is in a dynamic process, and once an operation error occurs, the treatment capacity of the entire system is likely to be greatly reduced. Due to the large system capacity of sewage treatment, the time constants of most systems are above 30 minutes or even several hours, and it is extremely difficult to achieve closed-loop automatic control operation. The long-term continuous fluctuation of the system has become the norm after being put into operation.

[0004] Currently, manual control methods are adopted in the biochemical treatment of centrifugal mother liquor. For the centrifugal mother liquor entering the buffer tank, all of it is either cooled by the cooling tower or directly discharged into the buffer tank without quantitative control. The pH value control is completely based on manual experience. According to the value displayed by the pH meter, the amount of acid and alkali added is determined manually. The addition of glucose for controlling COD is carried out by manual addition after chemical analysis and sampling.

[0005] The prior art has the following disadvantages:

[0006] Since the proportion of centrifugal mother liquor entering the cooling water tower cannot be adjusted online in a closed loop, the temperature of the buffer pool fluctuates greatly, affecting the subsequent biochemical process.

[0007] Affected by manual experience control, the lack of timeliness in adjustment leads to too large a fluctuation range in pH value control, and a large consumption of acid and alkali.

[0008] The COD control accuracy has not reached the best. Due to the influence of product grades and added additives, the composition of the centrifugal mother liquor incoming liquid changes continuously. The method of manually adding nutrient agents according to the COD test value cannot be accurately adjusted, resulting in excessive use of nutrient agents and economic waste. Summary of the Invention

[0009] Based on this, in view of the above technical problems, an intelligent control method and system for biochemical treatment of PVC centrifugal mother liquor are provided to solve the problems in the prior art that during the biochemical treatment of PVC centrifugal mother liquor, closed-loop temperature control cannot be achieved, the lack of timeliness in pH value adjustment leads to too large a fluctuation range in pH value control, a large consumption of acid and alkali, and the inability to accurately measure the COD content, resulting in excessive use of nutrient agents and economic waste.

[0010] In a first aspect, an intelligent control method for biochemical treatment of PVC centrifugal mother liquor, the method comprising:

[0011] Controlling the internal temperature of the buffer pool according to the ambient temperature and the temperature of the incoming liquid of the buffer pool; specifically: obtaining the target internal temperature of the buffer pool, calculating the internal temperature correction value of the buffer pool according to the ambient temperature and the target internal temperature of the buffer pool and obtaining the corrected internal temperature of the buffer pool, calculating the deviation between the corrected internal temperature of the buffer pool and the measured value of the current internal temperature of the buffer pool, inputting the deviation into an advanced control model for operation to obtain a valve action amount, and multiplying the valve action amount by the cooling water tower regulating valve regulating strength coefficient and the direct inlet buffer pool regulating valve regulating strength coefficient respectively and outputting to the cooling water tower regulating valve and the direct inlet buffer pool regulating valve;

[0012] Obtaining the target pH value of the buffer pool, calculating the pH difference between the target pH value of the buffer pool and the actually measured pH value of the buffer pool, inputting the pH difference into an advanced control model, and the advanced control model outputs the pH difference operation result to a splitting module, and the splitting module determines to open the acid adding regulating valve or the alkali adding regulating valve according to the pH difference operation result;

[0013] Obtain the target COD value of the buffer pool, calculate the COD difference between the target COD value of the buffer pool and the actually measured COD value of the buffer pool, input the COD difference into the advanced control model, the advanced control model outputs the COD difference operation result to the COD coordination module, and the COD coordination module adjusts the makeup water regulating valve or increases the frequency conversion of the nutrient auger or does not make any adjustment according to the COD difference operation result.

[0014] In the above solution, optionally, the obtaining of the target internal temperature of the buffer pool includes: calculating the target internal temperature of the buffer pool according to the biochemical treatment requirements of the PVC centrifugal mother liquor.

[0015] In the above solution, further optionally, the internal temperature measurement point of the buffer pool is at 0.5 m from the inlet of the cooling tower.

[0016] In the above solution, further optionally, the calculating the correction value of the internal temperature of the buffer pool according to the ambient temperature and the target internal temperature of the buffer pool and obtaining the corrected internal temperature of the buffer pool includes: calculating the correction value F(n) of the internal temperature of the buffer pool according to the ambient temperature correction formula F(n)=(T03 - T0)*KT, where T03 represents the ambient temperature, T0 represents the reference ambient temperature, and KT is a preset parameter.

[0017] In the above solution, further optionally, the advanced control model is a basic PID model superimposed with an expert system model.

[0018] In the above solution, further optionally, the obtaining of the target pH value of the buffer pool is to calculate the target pH value of the buffer pool according to the biochemical treatment requirements of the PVC centrifugal mother liquor.

[0019] In the above solution, further optionally, the obtaining of the target COD value of the buffer pool is to calculate the target COD value of the buffer pool according to the biochemical treatment requirements of the PVC centrifugal mother liquor;

[0020] The specific operation of the COD coordination module adjusting the makeup water regulating valve or increasing the frequency conversion of the nutrient auger or not making any adjustment according to the COD difference operation result is as follows: when the COD difference operation result is greater than the target COD value of the buffer pool, judge whether the centrifugal mother liquor water flow is greater than the preset reference centrifugal mother liquor water flow. If so, do not make any adjustment. If not, open the external makeup water regulating valve; when the COD difference operation result is less than the target COD value of the buffer pool, judge whether the centrifugal mother liquor water flow is greater than the preset reference centrifugal mother liquor water flow. If so, turn on / increase the frequency conversion of the nutrient auger. If not, do not make any adjustment.

[0021] In the second aspect, an intelligent control system for biochemical treatment of PVC centrifugal mother liquor, the system includes:

[0022] Temperature closed-loop control module: used to control the internal temperature of the buffer tank according to the ambient temperature and the temperature of the incoming liquid in the buffer tank; specifically: obtain the target internal temperature of the buffer tank, calculate the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank, and obtain the corrected internal temperature of the buffer tank, calculate the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, input the deviation into the advanced control model for operation to obtain the valve action amount, and multiply the valve action amount by the cooling tower regulating valve adjustment intensity coefficient and the direct inlet buffer tank regulating valve adjustment intensity coefficient respectively and output to the inlet cooling tower regulating valve and the direct inlet buffer tank regulating valve;

[0023] PH value precise control module: used to obtain the target PH value of the buffer tank, calculate the PH difference between the target PH value of the buffer tank and the actually measured PH value of the buffer tank, input the PH difference into the advanced control model, and the advanced control model outputs the PH difference operation result to the splitting module, and the splitting module determines to open the acid adding regulating valve or the alkali adding regulating valve according to the PH difference operation result;

[0024] COD control module: used to obtain the target COD value of the buffer tank, calculate the COD difference between the target COD value of the buffer tank and the actually measured COD value of the buffer tank, input the COD difference into the advanced control model, and the advanced control model outputs the COD difference operation result to the COD coordination module, and the COD coordination module adjusts the make-up water regulating valve or increases the frequency conversion of the nutrient agent auger or does not make any adjustment according to the COD difference operation result.

[0025] In a third aspect, a computer device includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0026] Control the internal temperature of the buffer tank according to the ambient temperature and the temperature of the incoming liquid in the buffer tank; specifically: obtain the target internal temperature of the buffer tank, calculate the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank, and obtain the corrected internal temperature of the buffer tank, calculate the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, input the deviation into the advanced control model for operation to obtain the valve action amount, and multiply the valve action amount by the cooling tower regulating valve adjustment intensity coefficient and the direct inlet buffer tank regulating valve adjustment intensity coefficient respectively and output to the inlet cooling tower regulating valve and the direct inlet buffer tank regulating valve;

[0027] Obtain the target pH value of the buffer pool, calculate the pH difference between the target pH value of the buffer pool and the actually measured pH value of the buffer pool, input the pH difference into the advanced control model, the advanced control model outputs the pH difference operation result to the splitting module, and the splitting module determines whether to open the acid addition regulating valve or the alkali addition regulating valve according to the pH difference operation result;

[0028] Obtain the target COD value of the buffer pool, calculate the COD difference between the target COD value of the buffer pool and the actually measured COD value of the buffer pool, input the COD difference into the advanced control model, the advanced control model outputs the COD difference operation result to the COD coordination module, and the COD coordination module adjusts the makeup water regulating valve or increases the frequency conversion of the nutrient auger or does not perform any adjustment according to the COD difference operation result.

[0029] Fourthly, a computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0030] Control the internal temperature of the buffer pool according to the ambient temperature and the incoming liquid temperature of the buffer pool; specifically: obtain the target internal temperature of the buffer pool, calculate the internal temperature correction value of the buffer pool according to the ambient temperature and the target internal temperature of the buffer pool and obtain the corrected internal temperature of the buffer pool, calculate the deviation between the corrected internal temperature of the buffer pool and the measured value of the current internal temperature of the buffer pool, input the deviation into the advanced control model for operation to obtain the valve action amount, and multiply the valve action amount by the cooling tower regulating valve adjustment intensity coefficient and the direct inlet buffer pool regulating valve adjustment intensity coefficient respectively and output to the inlet cooling tower regulating valve and the direct inlet buffer pool regulating valve;

[0031] Obtain the target pH value of the buffer pool, calculate the pH difference between the target pH value of the buffer pool and the actually measured pH value of the buffer pool, input the pH difference into the advanced control model, the advanced control model outputs the pH difference operation result to the splitting module, and the splitting module determines whether to open the acid addition regulating valve or the alkali addition regulating valve according to the pH difference operation result;

[0032] Obtain the target COD value of the buffer pool, calculate the COD difference between the target COD value of the buffer pool and the actually measured COD value of the buffer pool, input the COD difference into the advanced control model, the advanced control model outputs the COD difference operation result to the COD coordination module, and the COD coordination module adjusts the makeup water regulating valve or increases the frequency conversion of the nutrient auger or does not perform any adjustment according to the COD difference operation result.

[0033] The present invention has at least the following beneficial effects:

[0034] Based on further analysis and research of the problems in the prior art, it is recognized that in the process of biochemical treatment of PVC centrifugal mother liquor in the prior art, closed-loop temperature control cannot be achieved, the timeliness of pH value adjustment is insufficient, resulting in too large fluctuations in pH value control, large consumption of acids and alkalis, and inaccurate COD content, resulting in excessive use of nutrient agents and economic waste.

[0035] The present invention controls the internal temperature of the buffer tank according to the ambient temperature and the incoming liquid temperature of the buffer tank; specifically: obtaining the target internal temperature of the buffer tank, calculating the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank, and obtaining the corrected internal temperature of the buffer tank, calculating the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, inputting the deviation into an advanced control model for operation to obtain the valve action amount, and multiplying the valve action amount by the cooling tower regulating valve regulating strength coefficient and the direct inlet buffer tank regulating valve regulating strength coefficient respectively and outputting to the cooling tower inlet regulating valve and the direct inlet buffer tank regulating valve; obtaining the target pH value of the buffer tank, calculating the pH difference between the target pH value of the buffer tank and the actually measured pH value of the buffer tank, inputting the pH difference into the advanced control model, and the advanced control model outputs the pH difference operation result to the splitting module, and the splitting module judges to open the acid adding regulating valve or the alkali adding regulating valve according to the pH difference operation result; obtaining the target COD value of the buffer tank, calculating the COD difference between the target COD value of the buffer tank and the actually measured COD value of the buffer tank, inputting the COD difference into the advanced control model, and the advanced control model outputs the COD difference operation result to the COD coordination module, and the COD coordination module adjusts the make-up water regulating valve or increases the frequency conversion of the nutrient agent auger or does not perform any adjustment according to the COD difference operation result.

[0036] Compared with the existing solution, the temperature of the buffer tank in the present invention is changed from open-loop manual adjustment to closed-loop control, which can greatly improve the temperature control accuracy; by combining PID with the expert system algorithm to overcome the large lag characteristic in pH value control, the current situation that closed-loop automatic control cannot be put into long-term operation on site is changed. The adjustment of COD adopts two control strategies of water volume and nutrient solution addition to be coordinated, with timely response and reduced nutrient solution usage.

[0037] The present invention solves the problem of the adverse impact of the temperature change of the centrifugal mother liquor source on the biochemical process. It solves the problem of the adverse impact of the frequent change of water quality caused by different addition amounts of PVC additives on the biochemical process. Automatic control is realized, reducing the labor intensity of personnel, and reducing the labor cost and the cost of reagent use. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic flow chart of an intelligent control method for biochemical treatment of PVC centrifugal mother liquor provided by an embodiment of the present invention;

[0039] Figure 2 Schematic diagram of the existing biochemical treatment process for PVC centrifugal mother liquor provided by an embodiment of the present invention;

[0040] Figure 3 Block diagram of the temperature closed-loop control for the biochemical treatment of PVC centrifugal mother liquor provided by an embodiment of the present invention;

[0041] Figure 4 Block diagram of the precise pH value control for the biochemical treatment of PVC centrifugal mother liquor provided by an embodiment of the present invention;

[0042] Figure 5 Block diagram of the COD control for the biochemical treatment of PVC centrifugal mother liquor provided by an embodiment of the present invention;

[0043] Figure 6 Internal structure diagram of a computer device in an embodiment. Specific implementation manners

[0044] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0045] The intelligent control method for the biochemical treatment of PVC centrifugal mother liquor provided by the present application, as Figure 1 shown, includes the following steps:

[0046] Control the internal temperature of the buffer tank according to the ambient temperature and the incoming liquid temperature of the buffer tank; specifically: obtain the target internal temperature of the buffer tank, calculate the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank and obtain the corrected internal temperature of the buffer tank, calculate the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, input the deviation into an advanced control model for operation, obtain the valve action amount, and multiply the valve action amount by the cooling tower regulating valve regulating strength coefficient and the direct inlet buffer tank regulating valve regulating strength coefficient respectively and output to the cooling tower inlet regulating valve and the direct inlet buffer tank regulating valve;

[0047] Obtain the target pH value of the buffer tank, calculate the pH difference between the target pH value of the buffer tank and the actually measured pH value of the buffer tank, input the pH difference into an advanced control model, and the advanced control model outputs the pH difference operation result to a splitting module, and the splitting module judges whether to open the acid adding regulating valve or the alkali adding regulating valve according to the pH difference operation result;

[0048] The advanced control model has dual proportional-integral actions with deviation and deviation slope, the input signal has a preset dead zone function, and the output signal also has a variable dead zone range setting function.

[0049] Obtain the target COD value of the buffer pool, calculate the COD difference between the target COD value of the buffer pool and the actually measured COD value of the buffer pool, input the COD difference into the advanced control model, and the advanced control model outputs the COD difference operation result to the COD coordination module. The COD coordination module adjusts the makeup water regulating valve or increases the frequency conversion of the nutrient auger or does not perform any adjustment according to the COD difference operation result.

[0050] In one embodiment, the obtaining of the target internal temperature of the buffer pool includes: calculating the target internal temperature of the buffer pool according to the biochemical treatment requirements of the PVC centrifugal mother liquor.

[0051] In one embodiment, the internal temperature measurement point of the buffer pool is at 0.5 m from the inlet of the cooling tower.

[0052] In one embodiment, the calculating of the internal temperature correction value of the buffer pool according to the ambient temperature and the target internal temperature of the buffer pool and obtaining the corrected internal temperature of the buffer pool includes: calculating the internal temperature correction value F(n) of the buffer pool according to the ambient temperature correction formula F(n)=(T03 - T0)*KT, where T03 represents the ambient temperature, T0 represents the reference ambient temperature, and KT is a preset parameter. KT can be obtained through experiments, that is, when the ambient temperature changes by 1°C, record the temperature amplitude change of the internal temperature of the buffer pool accordingly, and take the negative value of this amplitude to obtain KT.

[0053] T0 represents the reference ambient temperature, that is, at this temperature, no temperature correction is performed and the temperature correction value is zero.

[0054] In one embodiment, the advanced control model is a basic PID model superimposed with an expert system model.

[0055] In one embodiment, the obtaining of the target pH value of the buffer pool is to calculate the target pH value of the buffer pool according to the biochemical treatment requirements of the PVC centrifugal mother liquor.

[0056] In one embodiment, the obtaining of the target COD value of the buffer pool is to calculate the target COD value of the buffer pool according to the biochemical treatment requirements of the PVC centrifugal mother liquor;

[0057] The COD coordination module adjusts the makeup water regulating valve, increases the frequency conversion of the nutrient auger, or does not perform any adjustment according to the COD difference operation result. Specifically, when the COD difference operation result is greater than the target COD value of the buffer tank, it is judged whether the centrifugal mother liquor water flow rate is greater than the preset reference centrifugal mother liquor water flow rate. If so, no adjustment is made. If not, the external makeup water regulating valve is opened. When the COD difference operation result is less than the target COD value of the buffer tank, it is judged whether the centrifugal mother liquor water flow rate is greater than the preset reference centrifugal mother liquor water flow rate. If so, the frequency conversion of the nutrient auger is started / increased. If not, no adjustment is made. The preset reference centrifugal mother liquor water flow rate means that through tests, when the centrifugal mother liquor water flow rate remains at F0, the fluctuation range of the COD value is less than the range required by the control index.

[0058] In the intelligent control method for biochemical treatment of the above PVC centrifugal mother liquor, the internal temperature of the buffer tank is controlled according to the ambient temperature and the temperature of the incoming liquid in the buffer tank; specifically: obtain the target internal temperature of the buffer tank, calculate the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank, and obtain the corrected internal temperature of the buffer tank, calculate the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, input the deviation into the advanced control model for operation, obtain the valve action amount, and multiply the valve action amount by the adjustment intensity coefficient of the cooling tower regulating valve and the adjustment intensity coefficient of the directly incoming buffer tank regulating valve respectively and output to the incoming cooling tower regulating valve and the directly incoming buffer tank regulating valve; obtain the target pH value of the buffer tank, calculate the pH difference between the target pH value of the buffer tank and the actually measured pH value of the buffer tank, input the pH difference into the advanced control model, the advanced control model outputs the operation result of the pH difference to the splitting module, and the splitting module judges to open the acid adding regulating valve or the alkali adding regulating valve according to the operation result of the pH difference; obtain the target COD value of the buffer tank, calculate the COD difference between the target COD value of the buffer tank and the actually measured COD value of the buffer tank, input the COD difference into the advanced control model, the advanced control model outputs the operation result of the COD difference to the COD coordination module, and the COD coordination module adjusts the make-up water regulating valve or increases the frequency conversion of the nutrient agent auger or does not perform any adjustment according to the operation result of the COD difference. Compared with the existing solution, the temperature of the buffer tank in the present invention is changed from open-loop manual adjustment to closed-loop control, which can greatly improve the temperature control accuracy; by combining the PID with the expert system algorithm, the large lag characteristic in pH value control is overcome, and the current situation that closed-loop automatic control cannot be put into use on site for a long time is changed. The adjustment of COD adopts two control strategies of water volume and nutrient solution addition to be coordinated, with timely control response and reduced nutrient solution usage. It solves the problem of the adverse impact of the temperature change of the centrifugal mother liquor source on the biochemical process. It solves the problem of the adverse impact of the frequent change of water quality caused by different addition amounts of PVC additives on the biochemical process. Automatic control is realized, the labor intensity of personnel is reduced, and the labor cost and the chemical agent usage cost are reduced.

[0059] In one embodiment, to solve the huge impact of the temperature change of the centrifugal mother liquor on the subsequent biochemical treatment, automatic adjustment is carried out when the centrifugal mother liquor enters the cooling tower and directly enters the buffer tank, the control accuracy of the mother liquor temperature in the buffer tank is improved and unattended operation is realized. Intelligent control is carried out on the key parameters pH value and COD value in water quality control to solve problems such as large adjustment lag, single adjustment means, and insufficient timeliness. Among them, the pH value control adopts the combination of PID and expert system control, and the COD is controlled in the form of a dual control strategy.

[0060] In one embodiment, as Figure 3 shown, the temperature closed-loop control:

[0061] At present, the temperature of the centrifugal mother liquor is controlled in two ways. One is to completely pass through the cooling tower with a fixed valve position, and the other is to distribute the liquid into the cooling tower and directly into the buffer tank with a fixed opening degree valve position. Neither of these two methods can well meet the systematic disturbances caused by the change of the incoming liquid temperature or the environmental temperature. There are mainly the following difficulties in the unclosed-loop regulation: Firstly, the buffer tank has a large capacity. If the temperature measurement point is not reasonably selected, the two-way flow of the incoming liquid cannot be controlled timely and accurately. Secondly, there is an obvious lag. The incoming liquid temperature changes frequently, and the manual regulation has too high labor intensity. After the conventional automatic control is put into use, there are continuous fluctuations.

[0062] Adopt the following control strategy:

[0063] Use the environmental temperature and the incoming liquid temperature as the feedforward to control the temperature in the buffer tank. The temperature measurement point of the buffer tank is arranged 0.5 m away from the incoming liquid of the cooling tower.

[0064] The control process is as follows. The process personnel set the basic control point of the buffer tank temperature according to the biochemical treatment requirements. The program automatically introduces the environmental temperature correction F(n)=(T03 - T0)*KT, where KT is a negative value, that is, the higher the environmental temperature, the lower the correction value. After comparing the corrected temperature control point with the current measured value of the buffer tank temperature, the deviation enters the advanced control model for operation. This model is a basic PID model superimposed with an expert system model. After calculating the valve action amount, it is multiplied by the adjustment strength coefficient of the cooling tower regulating valve and the adjustment strength coefficient of the valve directly entering the buffer tank respectively, and then output to the cooling tower regulating valve and the valve directly entering the buffer tank.

[0065] In one embodiment, as Figure 4 shown, the precise control of the PH value:

[0066] The PH value in the adjustment tank is related to the natural environment for the growth of biochemical bacteria. Once there is a large fluctuation, it will cause a large area of biochemical bacteria to be affected. It takes a long time to recover to the ideal state, so the impact is relatively large. The main control difficulty lies in the excessive lag. Here, a combination of predictive control and intelligent soft servo is adopted for control.

[0067] The control process is that the process personnel set the required PH value, and the difference between it and the measured value is sent to the advanced control model. In the application, a method combining the PID integral elimination model and the expert system adjustment step length is adopted for adjustment. The operation result enters the split range module, and the split range module judges whether to open the acid addition regulating valve or the alkali addition regulating valve.

[0068] In one embodiment, as Figure 5 shown, the COD control:

[0069] The centrifugal mother liquor water has a relatively simple composition and lacks the nutrients necessary for biological bacteria, unable to meet the metabolic needs. The growth nutrition of biochemical bacteria mainly consists of COD. When the influent COD is high and the water volume is small, it can be controlled by adjusting the influent water volume of the biochemical system without increasing the COD of the biochemical system; when the influent COD is high and the water volume is large, it is adjusted by adding external makeup water (fresh water or treated effluent) and using the dilution method.

[0070] The control process is as follows: The process personnel set the required COD value, and the difference between it and the measured value is sent to the advanced control model. In the application, a model that combines the PID integral elimination model with the expert system adjustment step is used for adjustment to overcome the process characteristics of large time constant and large lag, and to ensure that no continuous fluctuations occur. The judgment logic of the COD coordination module is: When the COD measured value is greater than the set value, it is judged whether the flow rate F01 is greater than F0. If so, no adjustment is made; if not, the external makeup water regulating valve is opened; when the COD measured value is less than the set value, it is judged whether the flow rate F01 is greater than F0. If so, the frequency conversion of the nutrient auger is started / increased; if not, no adjustment is made.

[0071] It should be understood that although Figure 1 the steps in the flowchart of Figure 1 are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover,

[0072] In one embodiment, an intelligent control system for the biochemical treatment of PVC centrifugal mother liquor is provided, including the following program modules:

[0073] Temperature closed-loop control module: used to control the internal temperature of the buffer tank according to the ambient temperature and the influent temperature of the buffer tank; specifically: obtain the target internal temperature of the buffer tank, calculate the correction value of the internal temperature of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank and obtain the corrected internal temperature of the buffer tank, calculate the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, input the deviation into the advanced control model for operation to obtain the valve action amount, and multiply the valve action amount by the cooling tower regulating valve adjustment intensity coefficient and the direct inlet buffer tank regulating valve adjustment intensity coefficient respectively and output them to the cooling tower inlet regulating valve and the direct inlet buffer tank regulating valve;

[0074] PH value precise control module: used to obtain the target PH value of the buffer pool, calculate the PH difference between the target PH value of the buffer pool and the actually measured PH value of the buffer pool, input the PH difference into the advanced control model, the advanced control model outputs the operation result of the PH difference to the splitting module, and the splitting module determines to open the acid adding regulating valve or the alkali adding regulating valve according to the operation result of the PH difference;

[0075] COD control module: used to obtain the target COD value of the buffer pool, calculate the COD difference between the target COD value of the buffer pool and the actually measured COD value of the buffer pool, input the COD difference into the advanced control model, the advanced control model outputs the operation result of the COD difference to the COD coordination module, and the COD coordination module adjusts the makeup water regulating valve or increases the frequency conversion of the nutrient auger or does not perform any adjustment according to the operation result of the COD difference.

[0076] For the specific limitations of the intelligent control system for the biochemical treatment of PVC centrifugal mother liquor, reference can be made to the limitations of the intelligent control method for the biochemical treatment of PVC centrifugal mother liquor in the above text, which will not be elaborated here. Each module in the above intelligent control system for the biochemical treatment of PVC centrifugal mother liquor can be implemented in whole or in part through software, hardware and their combination. The above modules can be embedded in the processor of the computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to the above modules.

[0077] In one embodiment, a computer device is provided. The computer device can be a terminal, and its internal structure diagram can be as Figure 6 shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input system connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a carrier network, NFC (Near Field Communication) or other technologies. When the computer program is executed by the processor, it realizes an intelligent control method for the biochemical treatment of PVC centrifugal mother liquor. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input system of the computer device can be a touch layer covered on the display screen, or a button, a trackball or a touchpad set on the shell of the computer device, or an external keyboard, a touchpad or a mouse, etc.

[0078] Those skilled in the art can understand,Figure 6 The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have a different component layout.

[0079] In one embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, which involves all or part of the processes in the method of the above embodiment.

[0080] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which involves all or part of the processes in the method of the above embodiment.

[0081] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to the memory, storage, database or other media used in the various embodiments provided by this application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0082] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0083] The above-described embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but they should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several deformations and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application should be subject to the appended claims.

Claims

1. An intelligent control method for biochemical treatment of PVC centrifugal mother liquor, characterized in that, the method includes: Controlling the internal temperature of the buffer tank according to the ambient temperature and the incoming liquid temperature of the buffer tank; specifically: obtaining the target internal temperature of the buffer tank, calculating the correction value of the internal temperature of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank and obtaining the corrected internal temperature of the buffer tank, calculating the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, inputting the deviation into an advanced control model for operation to obtain the valve action amount, and multiplying the valve action amount by the regulating intensity coefficient of the cooling tower regulating valve and the regulating intensity coefficient of the directly entering buffer tank regulating valve respectively and outputting them to the cooling tower inlet regulating valve and the directly entering buffer tank regulating valve; Obtaining the target pH value of the buffer tank, calculating the pH difference between the target pH value of the buffer tank and the actually measured pH value of the buffer tank, inputting the pH difference into an advanced control model, and the advanced control model outputs the operation result of the pH difference to a splitting module, and the splitting module judges to open the acid adding regulating valve or the alkali adding regulating valve according to the operation result of the pH difference; Obtaining the target COD value of the buffer tank, calculating the COD difference between the target COD value of the buffer tank and the actually measured COD value of the buffer tank, inputting the COD difference into an advanced control model, and the advanced control model outputs the operation result of the COD difference to a COD coordination module, and the COD coordination module adjusts the make-up water regulating valve or increases the frequency conversion of the nutrient agent auger or does not make any adjustment according to the operation result of the COD difference; The obtaining of the target internal temperature of the buffer tank includes: calculating the target internal temperature of the buffer tank according to the requirements of the biochemical treatment of the PVC centrifugal mother liquor; The internal temperature measurement point of the buffer tank is at 0.5 m from the inlet of the cooling tower; The calculating the correction value of the internal temperature of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank and obtaining the corrected internal temperature of the buffer tank includes: calculating the correction value F(n) of the internal temperature of the buffer tank according to the ambient temperature correction formula F(n)=(T03 - T0)*KT, where T03 represents the ambient temperature, T0 represents the reference ambient temperature, and KT is a preset parameter; The obtaining of the target COD value of the buffer tank is calculated according to the requirements of the biochemical treatment of the PVC centrifugal mother liquor; The COD coordination module adjusts the make-up water regulating valve or increases the frequency conversion of the nutrient agent auger or does not make any adjustment according to the operation result of the COD difference specifically as follows: when the operation result of the COD difference is greater than the target COD value of the buffer tank, judge whether the flow rate of the centrifugal mother liquor water is greater than the preset reference flow rate of the centrifugal mother liquor water, if so, do not make any adjustment, if not, open the external make-up water regulating valve; when the operation result of the COD difference is less than the target COD value of the buffer tank, judge whether the flow rate of the centrifugal mother liquor water is greater than the preset reference flow rate of the centrifugal mother liquor water, if so, open / increase the frequency conversion of the nutrient agent auger, if not, do not make any adjustment.

2. The method according to claim 1, characterized in that, The advanced control model is a basic PID model superimposed with an expert system model.

3. The method according to claim 1, wherein, obtaining the target pH value of the buffer tank is to calculate the target pH value of the buffer tank according to the biochemical treatment requirements of the PVC centrifugal mother liquor.

4. An intelligent control system for biochemical treatment of PVC centrifugal mother liquor, wherein, the system includes: Temperature closed-loop control module: used to control the internal temperature of the buffer tank according to the ambient temperature and the incoming liquid temperature of the buffer tank; specifically: obtain the target internal temperature of the buffer tank, calculate the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank and obtain the corrected internal temperature of the buffer tank, calculate the deviation between the corrected internal temperature of the buffer tank and the measured value of the current internal temperature of the buffer tank, input the deviation into the advanced control model for operation, obtain the valve action amount, and multiply the valve action amount by the cooling tower regulating valve adjustment intensity coefficient and the direct inlet buffer tank regulating valve adjustment intensity coefficient respectively and output to the cooling tower inlet regulating valve and the direct inlet buffer tank regulating valve; pH value precise control module: used to obtain the target pH value of the buffer tank, calculate the pH difference between the target pH value of the buffer tank and the actual measured pH value of the buffer tank, input the pH difference into the advanced control model, the advanced control model outputs the pH difference operation result to the splitting module, and the splitting module judges to open the acid adding regulating valve or the alkali adding regulating valve according to the pH difference operation result; COD control module: used to obtain the target COD value of the buffer tank, calculate the COD difference between the target COD value of the buffer tank and the actual measured COD value of the buffer tank, input the COD difference into the advanced control model, the advanced control model outputs the COD difference operation result to the COD coordination module, and the COD coordination module adjusts the makeup water regulating valve or increases the frequency conversion of the nutrient agent auger or does not make any adjustment according to the COD difference operation result; Obtaining the target internal temperature of the buffer tank includes: calculating the target internal temperature of the buffer tank according to the biochemical treatment requirements of the PVC centrifugal mother liquor; The internal temperature measurement point of the buffer tank is at 0.5 m from the inlet of the cooling tower; Calculating the internal temperature correction value of the buffer tank according to the ambient temperature and the target internal temperature of the buffer tank and obtaining the corrected internal temperature of the buffer tank includes: calculating the internal temperature correction value F(n) of the buffer tank according to the ambient temperature correction formula F(n)=(T03 - T0)*KT, where T03 represents the ambient temperature, T0 represents the reference ambient temperature, and KT is a preset parameter; Obtaining the target COD value of the buffer tank is to calculate the target COD value of the buffer tank according to the biochemical treatment requirements of the PVC centrifugal mother liquor; The COD coordination module adjusts the make-up water regulating valve or increases the frequency conversion of the nutrient auger or does not perform any adjustment according to the COD difference operation result. Specifically: when the COD difference operation result is greater than the target COD value of the buffer tank, it is judged whether the centrifugal mother liquor water flow rate is greater than a preset reference centrifugal mother liquor water flow rate. If so, no adjustment is made. If not, the external make-up water regulating valve is opened; when the COD difference operation result is less than the target COD value of the buffer tank, it is judged whether the centrifugal mother liquor water flow rate is greater than a preset reference centrifugal mother liquor water flow rate. If so, the frequency conversion of the nutrient auger is turned on / increased. If not, no adjustment is made.

5. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, when the processor executes the computer program, the steps of the method according to any one of claims 1 to 3 are implemented.

6. A computer-readable storage medium, having a computer program stored thereon, characterized in that, when the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 3 are implemented.

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