| Nowadays, pre-decomposition and suspension preheating are regarded as the core technology and have been widely used all over the world. The decomposing furnace is the core equipment of the pre-decomposition system. The main function of decomposing furnace is to pre-decompose the carbonate in cement raw materials, ensuring the decomposition rate reach the technical requirement before entering into the rotary kiln. The stability of decomposing furnace control has important effect on the stabilization of rotary kiln, the quality of final production and the safe running of equipments. The temperature of decomposing furnace has a direct affection on decomposition rate, therefore, the control ability of decomposing furnace temperature, which decides the stability of sinter process, the quality of final production and the equipment operation efficiency. Decomposing furnace is directly connected with rotary kiln and suspension pre-heater, which lead to the problem of severe equipment coupling. The process of furnace combustion, heat transfer and decomposition is complex. Thus, there are many difficulties in the process of temperature control, such as strong nonlinearities, pure lag, multi-variables, input constraints, uncertain disturbances. Since, the conventional control strategy can not meet the demand of control performance. As a result, predictive control for decomposing furnace is of great significant for improving the temperature control accuracy and improving the production quality and production efficiency.This dissertation has made research on the research and development of the temperature predictive of decomposing furnace, supported by the National Hi-tech863/CIMS and based on the1500tons/day new dry cement production line automatic project of Jiu-STEEL Group HongDa Building Material Co., Ltd. The research work of this paper is as follows:(1) The temperature predictive control for decomposing furnace is presented, after analyzed the difficulties and target of decomposing furnace process. The step response model has been established at the certain conditions by the simulation software for decomposing furnace quoted from reference[61]. In this paper, the unconstrained controller and the controller with input constraints are designed on the base of DMC (Dynamic Matrix Control) algorithm. Finally, the controllers are studied by simulation of setting follow and disturbance restrain. The result proves that the presented method has good control ability. (2) Based on the above control methods, the temperature predictive software has been designed and developed. According to the function of temperature predictive control software for decomposing furnace, the structure of predictive control software is divided into six modules:system management module, communication configuration module, controller configuration module, process monitor module, off-line simulation module and historic date management module. The software can be used to login the control system, communicate with S7-400PLC system, introduce step response model, according to the configuration parameters of control variable, manipulated variable, disturbing variable and controller parameter, generate DMC controller automatically, show real time date and trend of process variable, simulate with the simulation model, put the process date on file and check the history data. The function module and human interface are developed by programming software such as, Visual Basic6.0, Access2000and ProEssential v2.1on the base of Windows platform.(3) The function test of software has been conducted. The communication test of software has been carried out by WinCC Tag Simulator and then the test of controller configuration and simulation are conducted by simulation model. According to the test, we find that the predictive software for decomposing furnace accomplishes the required function and worth to apply in industry control. |
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