| NSP cement clinker production technology is the most advanced cement production methods in international. It consists of five relatively independent process, namely raw meal preparation, raw meal preheater and calcination (hereinafter referred to as the raw meal calcination), clinker calcining, clinker cooler, and pulverized coal preparation. Among them, raw meal calcination is a technical leap, and this process is setting a calciner between the preheater C5and the rotary kiln tail. This process with pulverized coal heat release and the carbonate decomposition absorption heat has happened, and the decomposition ratio of the raw meal (hereinafter referred to as RMDR) arrive at the interval (i.e.,85percent and94percent). The RMDR is important evaluation index of calciner efficiency, and the percentage of carbonate oxide in total carbonate. However, it is inevitable that preheater C5feeding tube is clogged when the RMDR is too high, even it cause halt. Conversely, the heat load of the rotary kiln will increase and the production capacity will reduce when the RMDR is too low.In raw meal calcination process, the index of RMDR can not be directly measured online, and the target value of RMDR is different in easy calcination stage and difficult calcination stage, meanwhile has the complicated relations with the raw meal flow and raw meal boundary conditions, and the dynamic characteristic between the RMDR and the calciner temperature and the preheater C5outlet temperature shows strong nonlinearities, and vary with the operation conditions. Therefore, it is difficult to describe the RMDR by a mathematical model. A relationship between the the calciner temperature and the preheater C5outlet temperature and calciner feeder shows strong nonlinearities, large delay, and vary with the raw meal flow. Thus the exsiting control methods are difficult to control the index of RMDR and the calciner temperature and the preheater C5outlet temperature. In industrial process, manual operation on raw meal calcination process is mainly used. However, on-site operators cannot accurately recognize the operatioanl conditions, and can not determine the calciner feeding in time when the boundary conditions of the raw meal, and raw meal flow frequently change. Such a manual control can lead to possible operational faults such as preheater C5feeding tube clogged, and lead to halt.The work conducted in this thesis was supported by the National863High Technology Program project of "the large rotary kiln intelligent control system and its application in complex industry process". The objective of this thesis is to control the RMDR within their required ranges and in the meantime to maximize the production capacity. This thesis focuses on the research on the intelligent control system for the raw meal calcination process. An intelligent control method is proposed; An intelligent control software based on above intelligent conrol method is developed. This intelligent control software has been successfully applied in a raw meal calcination plant in China. The main research of this paper concludes the following contributions:1. An intelligent control method which consists of easy calcination raw meal identification, difficult calcination raw meal identification, the process control of easy calcination raw meal, and the process control of difficult calcination raw meal is proposed. Among them, the process control both easy calcination raw meal and difficult calcination raw meal contain the target value setting model of the RMDR, the calciner temperature setpoint, and temperature switching control.2. The target value setting model of the RMDR based on subtractive clustering method and ANFIS produces the target value of the RMDR. Calciner temperature setting model consists of a pre-setting model based on T-S, a soft measurement model for RMDR, a feedback compensation model based on soft measurement model, and a feedback compensation model based on actual measured value. A soft measurement model by combining recursive fixed-memory principal component analysis (RFMPCA) with least squares support vector machines(LS-SVM) produce RMDR according to auxiliary variables set. A feedback compensation model based on soft measurement model calculate the compensation value of the calciner temperature by using the deviation of the target value of RMDR and the soft measurement value. A feedback compensation model based on actual measured value calculate the compensation value of the calciner temperature by using the deviation of the actual measured value of RMDR and the target value of RMDR.3. The temperature switching control contain the fuzzy-PI switching controller, an abnormal condition controller based on the rule reasoning, a feedforward controller based on the rule reasoning, and a switching mechanism based on the rule reasoning. The fuzzy controller adjust the coal feeder according to temperature tracking error. The feedforward controller compensate the disturbance of raw meal flow. The switching mechanism recognize condition and automatically switch abnormal condition controller when the abnormal condition happen, thus preheater C5outlet temperature within their target ranges.4. The intelligent control software based on the intelligent control method of the raw meal calcination process has been designed. The intelligent control software consists of the target value setting software of the RMDR, the setting software for calciner temperature, the temperature switching software, and the monitoring software.5. The intelligent control system has been designed and developed for the raw meal calcination process. It includes hardware platform, software platform, and intelligent control softwares. The hardware platform includes PLC control system, the measurement instruments, the transmitters, the actuators, the supervision computer and redundant net, etc. The software platform is based on the configuration software of process control. This application in practice industry shows that the switching control method copes with the automatic control of temperature, and makes the traching error of the calciner temperature was reduced by10%, and the preheater C5outlet temperature within their required ranges, thus avoids the faults such as "C5feeding tube clogged". Long-term operation results show that RMDR increases by7%and the production capacity increased by2.15%compared with the manual operation. |
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