Research Of On-line Combustion Optimization Control System For Coal-fired Boilers Considering Denitration Operation Cost

Nowadays,coal-fired power plant boiler combustion and flue gas denitration technology has high operating costs.Optimizing the operating costs of the boiler combustion and denitrification system,and improve the overall economy of the unit to make the power generation enterprises more competitive.In this paper,comprehensive economy on-line optimization problem in the combination of boiler combustion and SCR system is studied.A comprehensive system model of boiler combustion and denitration is built to realize on-line optimal control of comprehensive cost.The system can make the optimal setting of each operating variable according to the different working conditions of the unit,so that the emission can reach the standard while the integrated operating cost is the lowest.In this paper,the boiler combustion model and denitration efficiency model are combined.An improved genetic algorithm is used to filter the model input variables to improve the prediction accuracy.The comprehensive cost of boiler combustion and SCR system is proposed,under normal operating conditions GA is used on an off-line optimize of the unit,and improve the optimization scheme.So that the comprehensive cost is the lowest while SCR operating costs is also relatively reducing.Then,the optimal adjusted values of the manipulated variables are optimized to form the offline optimal database,and using algorithm to update the offline optimal database.On the basis of offline optimal database,this paper adopts fuzzy association rule mining algorithm to realize the optimization of on-line control of each operation variable.In the process of modeling,this paper compares the predictive ability based on GA-LSSVM model with the LSSVM model.The results show that the accuracy and the modeling speed of the model in this paper are higher than those of LSSVM.The optimization time of the online optimization scheme is shorter than that of the traditional method,and avoids frequent movement of the valve,so is more security.It is suitable for on-line optimal control of comprehensive cost of boiler combustion and SCR system.In addition,aiming at the balance of the NO_x concentration field in the SCR outlet,an ammonia injection online optimization control system is constructed to further improve the economy of the SCR system and increase the life of the catalyst.