Economic Analysis Of Thermal Power Plant Based On Comprehensive Benefit Index

There are many aspects that influence the economy of thermal power plant. For different power plants the intensity of influence of these factors is different, in fact, for the same power plant at different times, the degree of influence of these factors is also different. For the current economic indicators are not comprehensive enough to reflect all these influencing factors, based on concise, efficient and progressive principles, a indicator that is Comprehensive Benefit Index (CBI) which reflects the comprehensive economy of thermal power plant is put forward. And a new way of thinking is provided for comprehensive benefit analysis of the power plant. CBI is significant to the evaluation and comparison of the power plant in different periods or different power plants in the same period and the layout of power plant.Firstly, the calculation model of CBI is established. Each factor influencing CBI is analyzed and methods of improving CBI are put forward. The comprehensive benefit index (CBI) is calcalated with some power plant as the research target. Through the qualitative analysis and quantitative calculation, main factors which are coal consumption rate of power supply and load rate that affect CBI are found. Finally, the main measures to improve economic benifit of power plant is found, that is reducing the coal consumption and load optimization scheduling, etc.Secondly, based on the unified physical model and mathematical model of heat-economics analysis for the coal-fired power unit and the introduction of the matrix gradient operator, the impact of operating parameters on CBI is analyzed through power supply coal onsumption. Calculation models of the influence of variation of the auxiliary steam-water flux, heater terminal temperature difference upside and underside, extraction steam pressure loss, main steam pressure, main steam temperature and reheat temperature of steam turbine to CBI are established respectively. Due to analysis of the results of this paper, under different conditions when auxiliary steam-water flux and heater terminal temperature difference upside change the relative variation of CBI can be considered invariantly; when heater terminal temperature difference underside changes the relative variation of CBI has a linear relation with the load; when extraction steam pressure loss changes the fifth heater changes the relative variation of CBI has a quadratic function with the load but it has a linear relationship with the load for other heaters ;for main steam pressure, main steam temperature and reheat temperature, they respectively change one unit ,their impact on CBI is different,their respective influence degree on CBI under low load is bigger than that are under high load and the influence degree increases when load decreases; In the same conditions, when the auxiliary steam-water flux, heater terminal temperature difference upside and underside and extraction steam pressure loss change, some heaters should be paid special attention for their influence degree on CBI are greater; the relative variation of CBI has a linear relation with main steam pressure variation, main steam temperature and reheat temperature.Finally, the model of load optimal dispatch is established. Three load optimal dispatch solutions are calculated and analyzed. Several intelligent optimization algorithms are used to optimize the computation. At last, it is confirmed that genetic algorithms has a relatively higher searching precision among the algorithms. The factors considered in plan 3 are necessary and comprehensive. In the influence factors of load optimal dispatch in addition to the main economic indicator of fuel cost, the environmental cost shows significant influences on load optimal dispatch, followed by steam turbine valve point effect.To confirm the optimal solution and optimization method can make the operation costs to a minimum, which can improve the economic benefit of power plant.