The Research Of Control Mode Of Cement Decomposing Furnace

With the vigorous development of domestic estate industry and the accelerating transformation of building material industry, cement industry is now in the critical period of product structure adjustment and technical innovation. The precalcining technology of new dry process cement production technology and optimization control strategy has become the trend of the development of cement industry in China. Decomposing furnace is the core equipment of precalcining technology, it assumes the pulverized coal combustion in precalcining system, gas-solid heat transfer and carbonate decomposition and so on, and maintains the stability of furnace temperature is very important to thermal distribution and thermal stability of the system. Control process of decomposition furnace has the characteristics of nonlinearity, large time delay, and control parameter uncertainty, which decides the complexity of control.The study aimed at a 6000 t/d clinker production line of a cement plant in Shijiazhuang city. On the basis of analyzing the craft of precalcining kiln cement production, we find out the main influencing factors of temperature in cement decomposing furnace. Moreover, in combination with the actual conditions of the product line, the plan to control the furnace temperature stability by controlling the coal powder flow properly according to the tertiary air, raw material flow and other factors has been finalized, so as to balance the fuel heat release, tertiary air heat release, raw material decomposition heat and so on within the furnace. Based on the plan and the furnace temperature observation data, the heat balance equation model has been set up in this paper according to the actual heat affecting factors inside the system, and different parameters in the equation model have been estimated on line with the real time least squares algorithm to conclude the model. Meanwhile, a fuzzy control algorithm for forecast has been proposed. The coal feed amount, the raw material flow, the tertiary air flow, the kiln-tail exhaust volume and other variables are used as the inputs of the forecast model to forecast the decomposing furnace temperature variation trend. Then, the fussy controller gives the regulating amount of coal powder to adjust the furnace temperature in advance and finally control the temperature forecast and distribute the reasonable coal powder feed amount.As an engineering project for practical application, we have designed a set of control software based on the requirements of craft and process control. Data can be exchanged between control software and DCS system by OPC technology solutions. The research in this paper can provide helpful reference for the design of the same kind of cement decomposing furnace temperature control system.