Research On Optimized Control Method Of Calcination Temperature In Rotary Kiln In Cement Production Process

Relying on wide application and strong durability,cement occupies an irreplaceable position in basic engineering material.Calcination temperature is the main monitored parameter of rotary kiln process,which is the key process of new dry cement production.A logical and effective control to calcination temperature has important significance at the operational process of rotary kiln system.The complicated working condition and thermal inertia of rotary kiln itself lead to difficulties in building accurate mathematical model and the lag of temperature change.Multiple interference factors in production process lead to time variant control system parameters,and all these characteristics lead to difficulties in rotary kiln calcination temperature control.The thesis takes Northern Heavy Industries Group Co.,Ltd.built Habesha Cement Share Company 3000TPD Greenfield Cement Project Holeta,Ethiopia as the project context,basing on the knowledge of new dry cement production process and current control method of cement rotary kiln,built the mathematical model indicating the relationship between calcination temperature and coal feeding amount at rotary kiln head end by system identification toolbox with the data obtained from the production practice.Achieved the elementary control effect of temperature automatic adjustment and no steady state error exists with conventional PID control method.While constant parameters of this method have difficulties in adapting to complicated interference in calcination process,and if their variation range exceeds the limit,the control parameters need to be resettled.To improve the stability of rotary kiln temperature control system,considering the adaptability to nonlinear system of rule-based fuzzy control method from intelligent control field,the thesis introduced Self-adaptation fuzzy PID control strategy.Fuzzify the deviation and its changing rate and input them to fuzzy controller to proceed fuzzy inference and decision,and output the correct value of PID controller’s parameters.Add the corrected value to the original PID parameters to realize on-line adjustment of control parameters.At the end of the thesis,the simulation of Self-adaptation fuzzy PID control method was operated under MATLAB/Simulation circumstance.Compare the result with conventional PID control method in two aspects which are response to given step signal and the tracing ability to random signal and analyze.The results indicate that compared with conventional PID control method,self-adaptation fuzzy PID control method has less overshoot and shorter regulation time responding the input step signal and better tracing ability to random signal,and meanwhile strengthens the robustness of the system.Also,controlling the calcination temperature with self-adaptation fuzzy PID control method by adjusting the coal feeding amount at rotary kiln head end can obtain a positive effect on energy saving of rotary kiln system with the premise of ensuring the cement calcination temperature condition.