Realization Of Intelligent Control System For Industrial Coal-fired Boilers

With the fast development of scientific technology, control technology and computer technology, automatic control technique has penetrated into every aspect of people's production and life. How to apply the advanced theory of control technique to practical program has been a research subject for quite a while. This thesis will do some research on boiler, the nolinear controlling object which has a large input and output requirement and is lagging significantly, and realize intelligent control over it.Boiler is one of the important equipment which converts primary energy to secondary energy. Today, energy sources are becoming increasingly tight, the requirement for energy utilization is becoming higher and China is determined massively solve environmental problems. Under such circumstances, the requirements for control and administration of energy are stricter. However, China still possesses a large amount of boilers with low levels of automation, unable to provide thorough combustion and thus cause severe environmental pollution. Therefore, to materialize intelligent control over industrial coal-burning boilers is of significant importance.Based on the research on the theory of intelligent control technique, this thesis takes as an example the industrial coal-burning boiler for paper making in Yunnan Hongyan Paper Co., Ltd. After an analysis on the operating condition of these equipment, the thesis will come up with a whole set of practical system for boiler controlling. The main tasks and innovative points are as the following:First, the thesis will practice a systematic research on controlling the object boiler and adopt three-element control cascading adjustment to the water level adjustment of steam pocket, based on the dynamic features of the objects receiving water adjustment.Second, the controlling system of oxygen removal case takes its first trial on cascading adjustment and takes boiler's confluent as the front feed of case's liquid level adjustment, so as to ensure a stable influent of the case and guarantee the effect of removing oxygen.Third, the control of steam pressure is introduced into the combustion chamber temperature as a secondary console index and adopts the vague control system which takes the steam pocket pressure as the master index.Fourth, the combustion control system employs a strategy in which the steam flow is the front feed to directly control blast volume which controls coal feed amount and wind given amount. Using an intelligent control strategy combined by a vague auto-setting PID control and auto-optimizing control, it optimizes the ratio of wind and coal online and saves energy.Fifth, it designs the hardware configuration of the whole system, and develops the software of upper and lower computer, and thus ensures the normal operation of the whole system.The system has been running for more than one year, during which time equipment operate finely without any failure. The result shows that this system is flexible in controlling, responds rapidly and easy to operate.