Combustion Control Of Boiler Based On Intelligent Track Guiding Algorithm

In order to ensure safe operation and stable production of middle and small industrial boilers, the designing of automatic control system is very important. There are many parameters for coal fired steam boilers, such as drum pressure, air-coal ratio, furnace negative pressure. The design of control system must be overall consideration due to the mutual coupling between each control loop, large lag of technological process, nonlinear workmanship and the ever-changing conditions. The PID control algorithm has been widely applied to all kinds of industrial scene, but it is difficult to meet static characteristic and dynamic index. Overshoot, windup, failing to match the control features and characteristics cause running crash. The drum pressure of boiler in regulation process has difficulties of non-stationary, hysteresis and multivariable coupling, etc. So the drum pressure is often controlled by manual in many industrial field.In order to effectively improve the rate of self-control of combustion control system, an improved control algorithm is developed:Intelligent Track Guiding Control. It uses an first-order inertia link step curve as a model to transfer the controlled object and changes the traditional from "target control" to "process control". Separately measure the position deviation and velocity deviation of model and controlled object, using increment equation to weight combination, which make the controlled parameter following the guide curve reach the set value smooth. ITGC has a clear physical meaning and is easy to operate, overcoming the traditional PID controller’s output too large because of excessive deviation in step given initial stage and integral saturation in the actual industrial control field.ITGC is applied in drum pressure control of a SZL15-1.25-A Ⅱ horizontal coal fired steam boiler, and the setting value of drum pressure is 0.33 Mpa. After running down a long enough period of time and a variety of working conditions, automatic control can meet the technological requirements and realize the index of ITAE is 7.44 better than 26.58 in manual control, and automatic control is only 28% of manual control. Throughout the adjustment process, including the loop of given coal and grate, blast and cited wind, each control loop can cooperative change the control parameters in accordance with the different control algorithms, achieving stable operation of boiler combustion control system. Entire algorithm can be applied to not only the boiler system but also be extended to other industrial control process. It can achieve stable, accurate and fast control objectives and has a a great value of engineering reference value.