Sintering Flue Gas Desulfurization Process Overhead Temperature Intelligent Control Strategies And Industrial Applications

Steel industry accounts for about 8% of the world's SO2 emissions, which is second to coal fire industry. Sintering is a process producing the largest amounts of SO2 in the steel industry, therefore sintering flue gas desulfurization plays an important part in energy conservation and emission reduction of steel industry. In the mechanism of circulating fluidized bed, stabilizing tower top temperature is significant to improving efficiency of desulfurization. However, spray desuperheating is a complex process with time-delay, time-varying and disturbance. How to control tower top temperature is the key to improve efficiency of desulfurization.On the basis of analyzing the mechanism of CFB flue gas desulfurization, this paper summarized the main problems in tower top temperature control. By using intelligent control theory, an intelligent control strategy, which combines dynamic matrix control with feedforward compensation control, is proposed to achieve the stability of tower top temperature.First, according to the inertia and time-delay of spray desuperheating, an auto regressive with external model is used to describe this process, and identified by using least square method. A predictive model of dynamic matrix controller is established based on the step responsive coefficient. Then, to achieve the function of correction on-line, fuzzy correct control is adopted to solve the problem of model mismatch. Meantime, in order to suppress the influence of the disturbances, a compensating feedforward model is added to the system. According to the model's calculations, compensation value is computed while the disturbance changes. Simulations, based on the ARX model, verify.the effectiveness of the strategy proposed in this paper.To verify its value of practical application, in 360m2 sintering factory of an iron and steel enterprise, tower top temperature intelligent control is developed based on the original control system of CFB in an iron and steel enterprise. The running results shows that the system can stabilize the tower top temperature, suppress the influence of the disturbances and improve the efficiency of desulfurization.