Low NO_x And Economic Operation Optimization Of Gas Steam Combined Cycle Generating Unit

In recent years,China has suffered a serious fog and haze weather.Serious air pollution in some cities,especially in Beijing,Tianjin and Hebei,resulting in the air pollution index exceeded the upper limit of the inhalable particles concentration level,causing a serious impact on people's production and daily life.This paper analyzes the relationship between haze,PM2.5 and NOx.The study shows that NOx is a key factor leading to fog and haze.Taking Nanjing city as an example,through a comparative analysis of Nanjing optimal coal-fired units and existing gas turbine generators pollutant emissions,It is proposed that the 9F-class gas-steam combined power generating unit with large pollutant emission and emission intensity can be optimized by the way of combustion adjustment for the low NOx economical optimal operation.According to the operation optimization,this paper established a set of three optimization indexes:NOx emission intensity,economy and efficiency,a 9F gas steam combined cycle generating unit efficiency characteristic model,NOx emission and economic characteristic model.In the construction of energy efficiency characteristic model,a support vector machine(SVM)modeling method considering the influence of IGV angle is proposed,realizing the accurate description of compressor characteristics.In the model of NOx emission characteristics,this paper refers to a large number of literature and screening,and finally establishes the empirical formula of NOx emission estimation which is suitable for the unit model.In the construction of economic model,the concept of environmental value of pollutants is introduced,and the environmental benefits of NOx emission reduction are estimated.On this basis,this paper uses genetic algorithm(GA)to construct a single objective optimization analysis for the model.The results show that the NOx emission intensity is too high when the economy or energy efficiency is optimal,and the NOx emission is the lowest when the economy and energy efficiency are poor.In order to achieve the optimal comprehensive performance,the optimization algorithm of the non dominated sorting genetic algorithm with elitist reservation(R-NSGA-?)is applied to multi-objective optimization,the pareto solution front is obtained,and the optimal solution is obtained under the load conditions of 90%and 70%under different weight coefficients.Finally,this paper analyzes sensitivity of economy of the unit from the angle of energy price changes.The results show that the gas price is higher,the economic loss per unit of power after multi objective optimization is more obvious,and with the gas turbine power tariff increases,the economic loss per unit of power after multi objective optimization is remain unchanged.This study can provide important guidance and reference for the optimal operation of 9F combined cycle power plant.