Standard Working Template And Modeling Research For Cement Calciner

Calciner is one of the most important parts of cement production, which undertakes the tasks of combustion, thermal transmission and material decomposition. As is known to all, a higher calciner outlet temperature may cause cyclone preheater chocked and affect the normal operation of kiln system. Contrarily, a lower temperature may increase the system load and decrease the decomposition rate. Thus, calciner outlet temperature control is a core to outside decompose system of new dry process kiln. For the frequent changes of working conditions and time varying, nonlinear, large time delay of calciner itself, direct modeling will bring great errors. So, it is important to establish an accurate calciner mathematical model based on working template, which may contribute to its control.Under the support of energy efficiency analysis and control theory research on cement production(Natural Science Foundation Focused Project of Shandong Province: ZR2011FZ002) and condition recognition research on the new dry cement production(Natural Science Foundation Project of Shandong Province: ZR2010FM038), the main works of this dissertation are following.(1) For the accurate control of calciner outlet temperature, an exact calciner model is required. Because of the frequent changes of working conditions, a rational working template for modeling is necessary. Refer to the cement plant design code(GB 50295-2008), the standard working template of calciner is established by the experience from outstanding operators, field data from a 5000t/d production line and 3D curve of each variable, which lays the foundation for calciner modeling.(2) Based on the standard working template, the quantity of coal feeding, temperature of tertiary air and quantity of raw material feeding are selected as input variables, and the model of calciner outlet temperature from 870 to 880 is established by regression analysis.℃ ℃(3) Considering the practical application, the model with online correction ability to reflect the dynamic changes of calciner outlet temperature is necessary. Thus, on the basis of modeling method described in(2), a switching modeling method for calciner outlet temperature via grey correlation analysis is proposed. It can calculate the grey correlation degree of calciner outlet temperature with each variable online, and select the highest correlation variable for modeling, so as to establish the switching model when the calciner outlet temperature is from 870℃ to 880℃.(4) To establish the calciner mathematical model via the standard working template, an online T-S fuzzy modeling method is proposed based on modeling method described in(3). For the temperature of tertiary air is determined by its valve opening, which always keeps constant during operation, the quantity of coal feeding and raw material feeding are only selected as input variables for online T-S fuzzy modeling. Regression analysis and extreme learning machine are used to establish the sub model of calciner outlet temperature with online model correction. Then, the membership function is divided via characteristics of cement production to establish the T-S fuzzy model of calciner outlet temperature from 820℃ to 880℃.(5) To control the calciner outlet temperature accurately, the control method needs to formulate by the calciner model. Aiming at the calciner outlet temperature from 840℃ to 860℃, the calciner outlet temperature model is established based on regression analysis. On the above basis, a sliding mode control method is utilized to realize the control of calciner outlet temperature with stability analysis. Simulation results show the feasibility of proposed control method.