Boiler Combustion Monitoring And Optimizing Control Based On Inducing Radiant Energy Signal

Test method of combustion is strongly restricted by combustion behavior in coal-fired power plant boiler furnace. It is not obvious to improve the quality of load and combustion control at adopting new control theories and advanced algorithm, due to the lag of traditional caloric signal with the disturbance of coal quality or quantity. By digital image processing technique and deep excavation of flame image, obtained principle of Radiant Energy Signal(RES or E) is put forward. This is a new control strategy at inducing E into load and oxygen control circuit, which E gotten from combustion flame images is as a bridge.In this paper, present condition of boiler combustion monitoring and its optimizing control is analyzed. A set of flame image monitoring system in a 300MW coal-fired power plant has been designed according to the synthetic method of reference thermometric in boiler furnace. Hardware and software of the system are also designed at that time.The comparison between E and traditional caloric value signal is carried out. According to the principle and characteristic of synthetic method, a kind of monitoring method about E is put forward based on multipoint and three-dimensional flame images, which is obtained from a dozen of CCD cameras by weighted sum of different installed position and their parameter settings.On the basis of quantitative described correlation of E in thermodynamic system, the change regularity of E is researched, with the regulating capacity of the disturbance of total coal, secondary air register and tilt angle. At the same time, the dynamic characteristic of E is gotten, among the relationship of E with heat transfer in furnace and heat convection in flue gas. It is feasible to introduce E into load control circuit in simulation study.A new coordinate control model on inducing E, where it is against the defect of traditional coordinated control system, is put forward as a command signal, due to the fact that the burning rate may be rapidly responded combustion in furnace. This new control strategy in inner circuit of fuel, by using RES, instead of calorific value signal and pressure signal, is useful for increasing the dynamic characteristics of stabilization of load and pressure.Traditional combustion control strategy has been meliorated by inducing radiant energy signal(E) into oxygen control circuit on the basis of analyzing the association between E and air/coal ratio. Through modification and in-situ operation, the control property under the optimized air/coal ratio can always hold the E in high-level and response combustion condition correctly. The new industrial scheme is proved to improve the efficiency of unit about 1%, reduced discharge of pollution (NOx) above 12%. It is an ideal concept for economy and environmental protection.It is a stretch in concept to traditional coordinated control system at introducing RES into duct pilot in this paper. Through the research of this paper, the technical puzzle from"fast-slow-fast"to"fast-fast", which is more quick response to the disturbance of fuel as opposite to caloric value signal, has been resolved. It provides an available method of optimized combustion accommodation implemented here.