Study On Cement Rotary Kiln Modeling

Rotary kiln system plays an important role in cement production, which used more than 50% of the coal power injection and mainly decided the finally production and quality of cement, so the automatic control and process optimization becomes the key to cement production energy conservation and emissions reduction. However, the optimization control of rotary kiln and similar thermal system used to based on the operator model and now is gradually to the precise model of hybrid control method. So for cement rotary kiln process modeling is of great research significance, but owing to the complicated working conditions of the system make it hard for a single model to meet the control demand. Therefore, the main work in this task is based on hybrid system theory, the thermal system, prior knowledge, and support vector machine(SVM) method for cement rotary kiln modeling, and calcining zone temperature in the process of rotary kiln is the main key parameters. This paper sets up a dynamic model based on the typical working conditions of cement rotary kiln, which the calcining zone temperature as output variables.Finally, the research for the optimal control of cement rotary kiln provides a better way of modeling and simulation platform.Under the support of cement rotary kiln hybrid modeling for control research project(colleges and universities in shandong province science and technology plan projects: J12LN17), the main works of this dissertation are following.(1) Based on the theory of hybrid system to complete the overall design of the cement rotary kiln model structure. Mainly includes the dynamic system model and the model of switching events: choose the kiln head coal injection volume as the input varible, cement rotary kiln calcining zone temperature as the dynamic model of output; discrete event model for the study of the dynamic model switching between typical working conditions. Because the subject is to control the application, thereafter, the identification of various working conditions of cement rotary kiln system is studied on.(2)Rotary kiln system template standard conditions is established. For some cement plant historical data analysis and field operating human experience in shandong province, this dissertation is mainly based on the standard working conditions for modeling the cement rotary kiln, which portion including 90% of the normal production time. On typical working conditions, kiln head coal injection quantity is roughly three basic value about 10.9 t/h, 11.1 t/h, 11.3 t/h level, through the division of the dominant variable corresponding working condition of other parameters is obtained at baseline. Based on the research of typical working conditions for the next step research provides the reasonable preparation.(3)Soft sensor method research on cement rotary kiln calcining zone temperature. Rotary kiln calcining zone temperature is the main research varible, but the limitation of current detection technology, calcining zone temperature cannot be directly measured, therefore, on the basis of reading a large number of relevant references to choose the least squares support vector machine method(LS_SVM) soft measurement of free CaO. At last, through the free CaO and the linear relationship between temperature, indirectly get the calcining zone temperature based on typical working conditions.(4)Research on typical working conditions of calcining zone temperature dynamic models. By the operators experience and refer to the literatures, the temperature of calcining zone is mainly influenced by kiln head coal injection, so based on typical working conditions are studied the dynamic system models between the kiln head coal injection as input varible and the calcining zone temperature as output varible. Finally, through the corresponding conditions of other data to validate the accuracy of the models, it can basically simulate the field situation and be practical.(5)The study of dynamic models switching between the typical working conditions. Due to the long running process of cement rotary kiln is switching process between typical working conditions, however, switching between condition presents a nonlinear and discrete, in this paper fuzzy model for dynamic model is set up. Finally, the efficiency and applicability of the method is demonstrated by simulation results.(6)Finally,realized dynamic simulation platform for control of cement rotary kiln. Mainly includes: establish condition recognizer, calcining zone temperature dynamic models configuration design at DCS engineer station, the calcining zone temperature dynamic models switch, the communication between DCS and the database, the database storage design. Then built cement rotary kiln model simulation platform, showed the trends in Digivis environment, including the related variables and kiln head coal injection and the real-time dynamic response of the temperature curve, the simulation shows that the principle and modeling methods used in this article is reasonable and effective.