The Research On Control Method Of Predecomposition And Calcination Process In Rotary Kiln System Of Cement Production Line

Cement production of new dry process technology is a large energy consumption industry, especially, the predecomposition process and calcination section of raw material in rotary kiln need a large amount of heat to maintain the fundamental reaction temperature, however unreasonable control strategies are very easy to cause the unnecessary energy consumption. Besides the predecomposition and calcination process are full of obvious time-delay, great inertia, nonlinear and uncertain disturbances, which will result in the unstable factors. So, compared with the regular methods, the predecomposition and calcination link optimization of new dry process cement production technology will lead the important role in industry energy saving, consumption reduction and environmental protection, and the work has been done as follows:High temperature fan plays an important role in maintaining the kiln system air pressure during cement manufacturing, whose stable operation is bound to have a vital effect on sustaining a specific negative pressure and air-solid separation of raw material in preheater. This paper uses high voltage inverter to adjust the fan's speed in real time and aiming at eliminating the slip loss and achieving the effect of energy saving. Due to the calcination process in rotary kiln is totally on the status of artificial or semi-automatic control that could be influenced by working conditions and hardly to keep the best operation conditions, consequently, in view of the coal feeding, this paper expounds the fuzzy cascade intelligent control scheme via modifying coal feeding volume to adjust sintering zone front temperature of rotary kiln rapidly. This core control scheme is when the temperature of rotary kiln is stable, coal inputting variable is controlled by inner loop PID controller, otherwise, the outer loop fuzzy algorithm will figure out a proper coal feeding and readjust the set point of inner loop coal feeding on line by the feedback data of real time sintering zone front temperature in order to stabilize the temperature that the reaction needs. Compared to regular PID control curves, the simulation experiments confirm that this scheme can improve the system dynamic and robust performance.It is very important for the cement production to guarantee the air permeability of rotary kiln, as it can be represented the empennage temperature of sintering zone directly. Although the temperature is mainly controlled by coal feeding volume, the raw material feeding is still a key factor in terms of steadying kiln temperature; then it is significant for sintering zone empennage temperature to adjust the raw material feeding. Consequently, this paper introduces the feedforward adjusting mechanism of oxygen level, expounds that regulating raw meal feeding could guarantee the air permeability and stabilize the sintering zone temperature of rotary kiln under the condition of the stable coal feeding. For the sake of controlling the calcination process of raw material better, this system based on asymptotic stability principle employs adaptive internal model control, which is superimposed on the feedforward signal from the oxygen level in cyclone preheater to jointly control the slip motor and then increase or decrease the raw material feeding. Furthermore the feedforward adjustment of oxygen level could act on the revolving plow reclaimer in advance and adjust the raw material feeding in time to keep the thermal regulation steady. This control method exceedingly improves the dynamic and steady state performance of sintering zone temperature control and strengthen the control system robustness; finally the simulation results note that this method can realize the better control effect, and achieving the goal of energy saving and consumption reduction.