Study On System Identification Of Alumina High Pressure Dissolution Temperature

In Bayer process, high pressure digestion temperature is the main factor affecting the leaching rate; Using double stream digestion process of high pressure digestion of Zhongzhou aluminum plant, Dissolution temperature control still use manual adjustment, strong dependence, temperature fluctuations in large, not only high energy consumption, it is hard to ensure the rate of alumina digestion. The chemical reaction of alumina digestion is a reversible reaction, it is difficult to model accurately on the basis of physical and chemical reaction, and the high pressure autoclave temperature model rarely published research. The temperature parameter setting and control is difficult to achieve the ideal effect. For the realization of alumina digestion temperature automatic control, to improve the system response characteristic, this paper used the non-parameter model identification and parameter identification model to identify the system.After three groups production of Zhongzhou aluminum plant dissolution for nearly five months more than ten thousand set of temperature data analysis and research, selecting two groups of different period data collected to analysis. In the process of nonparametric model identification, using the step response method to identify system step response curve; In the process of parameter model identification, the Structure and order of the model were identified. Identification results show that the parameter of the model identification of the fit of the model and the actual curve is higher; The identification results show that:Using parameter model identification of the model and the actual curve fitting degrees higher; Through the data cross validation method and residual analysis to verify the validity of the model; Algebraic stability criterion shows that the system is stable, the system can be closed-loop automatic control. In order to realize the automatic temperature control, adopts sub-optimal model order reducing algorithm to identify First Order plus Pure Dead Time (FOPDT) model. The last of the closed loop control system is designed, using the Ziegler Nichols Tuning of PID parameter setting. Through Matlab/Simulink simulation is given to illustrate the effectiveness of the control, it is concluded that the PID control parameters can be directly guide the practical production. The model of system identification provide the model basis for parameter tuning, optimization control; Not only improve the alumina digestion temperature closed loop PID control precision, but also reduce the manual, energy consumption, improve the economic benefit of the enterprise. For solving the alumina digestion temperature control and intelligent optimization had some beneficial attempts and approaches, and provides an important means to temperature characteristics of high pressure digestion.