Study On Optimal Allocation Of Heat Supply Units Based On Thermal Load Characteristics

After power generation,the steam of back-pressure units are all as outside heat-supply,due to the elimination of the cold source loss,its thermal efficiency is as high as 80%-90%,it can have high energy use efficiency.China expressly provides for priority use of back-pressure thermoelectric units in cogeneration projects,and strictly controls the planning and construction of large coal-fired extraction condensing units.However,at the end of twentieth Century,due to long-term low operating conditions and other issues in most of the thermal power plant,the superiority of back-pressure units is difficult to play,and the development of back-pressure units was once in a trough.Therefore,how to ensure the efficient operation of the back-pressure thermoelectric units,how to exert the advantage of the energy saving of the back-pressure thermoelectric units is an important research topic in the current domestic energy and environment background.In view of coal-fired cogeneration district heating system,using the heating load characteristics as the research object,through energy analysis and economic analysis,the author studies the optimal allocation of heat source heating system based on the back pressure steam turbine.The author discusses and analyzes the characteristics of several common heating load,indicates the importance of peak heating ways,and thermalization coefficient of heat source configuration on the efficient operation of back pressure units with the hot load duration figure,the method to selecting thermalization coefficient should be more reasonable.Based on the common energy efficiency evaluation index comparison and analysis,it obtained that a relative energy saving rate is an important parameter of thermalization coefficient of energy,the author analyzes the influence of thermal characteristics of back pressure unit,the number of units,comparison reference of the separate generation of power and heat,meteorological parameters in heating load,and the proportion of hot water load on energy saving optimal thermalization coefficient.Through the analysis,it defines the "high efficiency and energy saving area",which the difference between RPES and the theoretical maximum RPES is small,around a certain range of the energy saving optimal thermalization coefficient.The results show that thermal characteristics of back pressure unit and comparison reference of the separate generation of power and heat,meteorological parameters in heating load have almost no effection on energy saving optimal thermalization coefficient,but influences greatly on RPES.The increasing of the number of back pressure units can increase the optimal coefficient of heat.Energy saving optimal thermalization coefficient is highly correlated with meteorological parameters in heating load,the increasing of proportion of hot water load also increases the energy saving optimal thermalization coefficient.With the establishment of the economic optimal thermalization coefficient calculation model based on the minimum unit heating cost as the objective function,the author analyzes the effects of fluctuation of economic parameters on the economic optimal thermalization coefficient.The results show that the value of economic parameters has a great influence on the calculation of heating cost of cogeneration system.The actual project should be determined according to the planning area,and the economic optimization model should be used to calculate the actual cost.Finally,the results are applied to the actual cogeneration project to optimize and evaluate the heat source configuration.In the heat and power cogeneration project of SuiNing BaoYuan,The scheme designed by this method is 27.3%less energy than the previous one.