Economic Optimization Control And Simulation Of SCR Denitrification System Of Power Plant

Thermal power units dominate the power industry in China and will not change for a long time in the future,the flue gas containing nitrogen oxides(NOx)and other pollutants emitted by thermal power units is still one of the main sources of air pollution.In response to the national call for energy conservation and emission reduction,most thermal power plants currently use low-nitrogen combustion technology and flue gas denitrification systems to reduce NOx emissions.However,the denitration process will incur high costs and affect the efficiency of the power plant.This paper mainly studies the problem of economical operation of denitration in thermal power plants,and establishes a joint denitrification economic optimization system for thermal power plant boiler systems and selective catalytic reduction(SCR)denitrification systems.This system mainly includes three parts:the establishment of the joint denitrification operating cost model,the optimization of denitrification economics and the establishment of an expert database of denitrification economics.Through this system,the operator can adjust the operating parameters of the boiler system and the SCR system to make the unit run in the most economical state,so as to realize the optimal control of the denitrification economy of thermal power plants.When establishing the joint denitrification operating cost model,the parameters are first divided into adjustable parameters and non-adjustable parameters according to the operating status of the unit.Therefore,the integrated modeling method is used to model the boiler combustion system to solve the problem of multiple operating conditions of the thermal power unit.A single LSSVM model is established to compare with the integrated model proposed in this paper.The results show that the integrated model predicts more accurately for samples under multiple operating conditions,and the model training takes less time.Then the output parameters of the boiler combustion system model and the ammonia spray are used as the input of the SCR system model to establish a joint model.Finally,the cost calculation model is established,which mainly considers the power supply coal consumption of the boiler system and the reductant consumption and sewage charges of the SCR system.The joint denitrification operating cost model has good adaptability to the multi-condition operation of thermal power units.When optimizing the economics of denitrification,the particle swarm optimization(PSO)algorithm is used to optimize the adjustable parameters of the joint denitrification operating cost model,non-adjustable parameters are used to guide which sub-model of the integrated model the adjustable parameters are in.The optimization results show that the denitration cost of the boiler combustion system and SCR system has been reduced.Taking the PSO optimization results as the optimal operating parameters,the fuzzy association rules mining(FARM)algorithm is used to mine the association rules between the non-adjustable parameters and the adjustable parameters,and build the denitration economic expert database.The non-adjustable parameters are used to extract the optimal adjustable parameters from the denitration economic expert database to realize the optimization of denitrification economy.Compared with the traditional optimization,the mining algorithm based on the denitration economic expert database can effectively reduce the operating cost and greatly reduce the time-consuming,which provides certain guidance for the online optimization of the economics of thermal power plants.Finally,this article is based on Aspen Plus software to simulate the SCR denitration system,and establish the SCR system model in Aspen Plus software,an interactive interface is constructed between Aspen Plus and Matlab.Using the PSO optimization algorithm in Matlab to optimize the parameters of the Aspen Plus model to improve the predictive ability of the model.Aspen Plus accurately simulates the chemical changes of the reaction materials during the reaction process,which provides a model basis for the design and implementation of optimal control strategies for denitration economy.