Study On The Application Of Multi Mode Intelligent Control In Alkali Recovery System Of Paper Mill

With the development of economy,people's living standards have been raised,and people's demand for quality of life has increased accordingly.It's important to have a healthy living environment.The paper industry is closely related to our life,and our country has become the largest producer and consumer of paper in the world.However,the paper industry is a typical high-polluting industry,especially in papermaking process,which produces a lot of slurry waste,which seriously damages the ecological environment.Paper mill wastewater emissions from most(black liquor)is formed in the alkaline pulping process,so want to fundamentally solve the problem of waste pollution,you have to research paper mill alkali recovery system.First,through the comparison of various black liquid treatment strategies,it is the best choice to deal with black liquor with alkali recovery method.This paper analyzes the process of the alkali recovery system in the paper mill,and it is known that the smooth liquid level of black liquid in the flash can play an important role in the good running of the alkali recovery system.Secondly,the control of the liquid level of black liquid,the traditional control method is proportional control or PID control.However,due to the characteristics of non-linearity,time-delay and time-invariance,it is difficult to obtain good control results with traditional control methods.Now the fuzzy control is on the rise,and it has the characteristics of rapid reaction and good robustness.In order to obtain better control effect,the researchers designed the switching threshold of multimode controller,this controller has the advantages of various control methods,can better realize the black liquor of liquid level control.But by analyzing the structure of the threshold switch controller,there must be fluctuation interference between different control modes.In order to get better control effect,this paper put forward based on fuzzy switching multimode control method,this method is realized through fuzzy reasoning judgment no difference between different control mode switching.The mathematical model of the liquid level in the flash tank was analyzed,and the simulation simulation of the liquid level response was carried out using MATLAB software.Simulation results show that compared with the PID control and switching threshold of multi-mode control,using multi-mode control method of fuzzy switching control of black liquor level can achieve better control effect.Finally,according to the need of the alkali recovery system,the relevant hardware and software equipments are configured.Through the USS communication protocol,the PLC communicates with the frequency converter,and the PLC sends control instructions to keep the liquid level of black liquid in balance.To establish the communication between PLC and Win CC,create the monitor interface and simulate it through Win CC.