Research And Design On Dosing Coagulation And Chlorine Control System Of Intelligent Waterworks

With the improvement of living standard and the continuous improvement of control technology,the water quality of tap water in China has been put forward more and more high requirements.For the water treatment process,the dosing control of coagulant and chlorine is the most important part of the water purification process.Accurate coagulant and chlorine dosing are the key steps to ensure water quality and economic benefits of waterworks.Based on the actual situation of the new South Taihu waterworks,this thesis makes a complete and systematic analysis of the process of adding coagulation and chlorine.First of all,through a large number of relevant literature,from the impact of water coagulation and disinfection of the main factors to start,the preparation model of the original coagulation solution,the preparation model of coagulation,the addition of coagulation control model,the former chlorine-chlorination model and the latter chlorine-chlorination model are established after the parameter variables are determined.Then,this thesis gives the formula of the relationship between the parameters and the workflow of the model.through the above technical data,the researcher can write the PLC program for the control process and design the computer monitor interface of the system.After six months of automatic production operation,the model design in the pharmaceutical preparation and dosing have achieved good control effect.Finally,this thesis also makes a further theoretical simulation study on coagulation dosing control system.For the system characteristics of large lag,nonlinearity and time-varying in the process of adding coagulation,it is found that the simple feedback control circuit is difficult to guarantee the quality of the factory water.Therefore,this thesis puts forward a cascade DMC-PID control method,which is used to solve the problems caused by the delay of response,the unstable quality of the factory water and the low precision of coagulation dosing.In the thesis,the design of adding coagulation Cascade DMC-PID control system to the water flow for the internal loop of the controlled amount,temperature,pH value and other interference factors as the feed-forward detection,these parameters adjust the dosing frequency of the metering pump together.The amount of dosing of metering pump is directly adjusted by controlling the turbidity of the outer ring.the simulation analysis of the three control strategies which the control object adopts single loop PID,Cascade PID and Cascade DMC-PID shows that the control performance of Cascade DMC-PID control algorithm is superior to the other two methods,which can quickly adjust the dosing,reduce the alum consumption and realize high efficiency and Economic water supply.the dosing control of alum and chlorine provides a new idea for the construction of automatic control system of waterworks,and it is instructive for engineering practice.