Thermoeconomics Analysis Of Different Integration Modes Of Waste Heat Utilization System Of Boiler

As the increasingly severe problems of energy and environment,coal-fired units are faced with a huge pressure of energy saving and emission reduction.Recycling the flue gas waste heat of power plant boiler,can not only improve the economy of power plant,save the coal consumption,and can reduce the pollution of the environment.Reasonable evaluation of flue gas waste heat utilization system is an effective way to achieve energy saving and optimization of the unit.In this paper,the method of thermoeconomic structural theory is applied,based on a 350 MW unit,making calculation of thermoeconomic cost and environmental cost of waste heat utilization and air heating system(Case 2)?two stage flue gas waste heat and water recovery system(Case 3)?two stage MGGH waste heat utilization system(Case 4)three kinds of integration of waste heat utilization of coal-fired power plant boiler,and compared with the original unit(Case 1).Making exergy and thermoeconomic analysis of four systems,and calculating its environmental damage cost.The environmental effects of pollutants: 2SO ?XNO ?2CO and soot,are mainly considered.At the same time,making comparison and analysis of exergy cost for waste heat utilization system under variable load conditions,considering the advantages and disadvantages of various integration modes.The results show that,the unit exergy cost of product and thermoeconomic cost of Case 2?Case 3 are lower than the original unit,indicating that it has good energy saving effect.Case 4 in order to take advantage of the waste heat more deeply,control the heat transferring area of each component of the waste heat utilization system,causing the irreversible loss increases,the thermoeconomic cost high.Evaluate four kinds of integration modes through the relative cost difference and the energy loss ratio.And the environmental cost of Case 4 is lower than other three integration modes,indicating that it has the most optimal environmental effect.The system dynamic analysis under variable load,can guide the system operation and optimization.