Study On Temperature Control Of Cement Rotary Kiln

Rotary kiln calcining process is the key link of cement clinker production.It improves the quality of cement clinker by adjusting the kiln head coal injection to stabilizing the rotary kiln temperature.Therotary kiln coal injection accounts for about 40% of the total coal consumption of cement clinker production.However,the large lag,nonlinear and multi variable coupling characteristics of rotary kiln,most of the domestic cement rotary kiln system is controlled by manual control method.But the manual control level is uneven,it is difficult to ensure the stability of the kiln,and high energy consumption.Although some foreign optimization control software has a good control effect,but it is difficult to apply domestic cement plant production status.Therefore,based on the present situation of rotary kiln control in china.It is an urgent task to study the advanced control strategy to realize the optimal control of rotary kiln calcination process,to stabilize the rotary kiln calcination temperature,to reduce the energy consumption and to improve the quality of cement.This paper takes 5000t/d clinker production line of onecement company in Shandong Province as the research background,on the basis of understanding the production process,combined with the expert experience,adopt multi-mode intelligent control method,propose the overall optimal control scheme of cement rotary kilntemperature.Then,the software of the overalloptimal control system for cement rotary kiln is developed by using the object oriented programming method.Specific research contents are as follows:(1)Research on the optimal setting system of cementrotary kiln temperature.Based on the technology of cement burning system,combined with the experience of experts in operation,LS-SVM was used to set up the pre-setting model of rotary kilntemperature.Based on the analysis of different kiln conditions and the f-CaO of the material from the rotary kiln,the expert correction rule of temperature pre-setting value is established,correction of pre setting temperature of rotary kiln,used to modify the pre setting temperature of rotary kiln,the optimal setting value of the rotary kiln temperature is obtained,which is the control target of the automatic control system of the rotary kilntemperature.(2)Research on the automatic control system of cement rotary kiln temperature.According to the characteristics of large delay,nonlinear and multi-variable coupling of the rotary kiln,a multi-mode intelligent control scheme is proposed,which combines Bang-Bang control,expert rule control,feedforward control and fuzzy-PID compound control.Under the stable condition of kiln,the fuzzy-PID compound control is used to realize the temperature control of rotary kiln.When the kiln condition changes,according to the multi-mode intelligent switching rules,the controller under the corresponding mode is adjusted to the fuzzy-PID compound control,and the temperature of the rotary kiln is stable at the optimum setting value.Then,the typical working condition of rotary kiln is selected,simulation verification is carried out.(3)The software development of temperatureoptimal control system for rotary kiln.According to the overall optimal control scheme of cement rotary kilntemperature,using object oriented programming strategy.The whole system software is divided into data acquisition subsystem,database subsystem,optimization control subsystem,and developed one by one.Realization of data interconnection between optimization control subsystem and database subsystem by ADO.Data acquisition subsystem is used to realize the interconnection between database subsystem and field DCS system.Finally,the software is applied to cement production.The results show that the temperature is more stable and the coal consumption is lower.Therefore,the research of this topic is of great significance to the high production and low consumption of cement clinker.