Design And Develoment Of Optimal Control System In The Cement Raw Material Blending Process

The cement raw material blending process is an important process in the cement production. The purpose is various raw material according to a certain proportional quality mixed into cement raw finished products, every chemical element content index in the cement raw determines to the quality of finished cement products. The cement raw material blending process has the problem of multivariable, hysteresis, nonlinear and the big fluctuation the every chemical element in cement raw material, using conventional methods of blending composition may lead to the cement raw finished products are instability. According to the characteristics of biending process, this thesis has deeps investigate the cement raw material blending process, main reseach contents optimization control method, control system, monitoring system cosisit of hardware–in–the-loop simulation platform, the detail contents are follows:(1) The optimal control system is divided into optimization setting layer and the loop control layer. Optimal setting layer include optimization calculation model and adjust model. Its main function is optimal calculation through the sequential quadratic programming optimal method, and obtained the set-points of the satisfactory quality indicators. The bottom control loop uses PID method to control the folw, and the purpose is actual-points fiow reach the set-points.(2) Design and development of the raw cement optimize control system by using the large controller siemens S7-400 PLC is finished, including hardware design and software development.(3) The S7-400 PLC, Matlab software, Win CC monitoring software, VB programming software through different communication ways composed of a system, in the system has the optimization calculation, the establishment of the model, real-time monitoring, simulation and other functions, based on the hardware-in-the-loop simulation platform for the research of the whole cement raw material blending process, improving the work efficiency and economy, also makes up the defect of the traditional simulation and field test.Research results show that, the sequential quadratic programming is used to the cement raw material blending process, improving accuracy and quality of the cement raw material blending fomula, using of the Siemens controller combined with simulation software, not only avoid the defect of the traditional simulation, and make the results more close to the real results.