Thermoeconomic Analysis Of Heating Methods Of Combined Heat And Power 300MW Air-cooling Unit

At present,China’s demand for efficient use of energy and reduction of carbon emissions is increasing,and the growth rate of energy demand has dropped to about 1%per year.Relatively,energy intensity needs to be greatly improved,which means that energy utilization efficiency needs to be greatly improved.At present,in the share of central heating,fossil energy still accounts for the main share.Among them,fossil energy for pure heating still account for a relatively high proportion.It is a wasteful use for high-grade energy generated by combustion.Replacing a certain share of the pure heating units with combined heat and power units can realize the cascade utilization of energy and improve the overall utilization efficiency of energy.This thesis takes a 330MW steam extraction cogeneration unit as the research object.Designed a high back pressure heating operation method and a extraction steam-high back pressure dual unit combined heating operation method.Analyzed the power generation,power supply coal consumption rate,heat-to-power ratio,total energy efficiency and exergy efficiency of the three operation methods under the conditions of different chosen main steam flow rate,heating load,and supply and return water temperature.Pointed out that the dual unit combined heating operation method has certain advantages in thermoeconomic compared with the other two methods,but it also has some disadvantages.This thesis also calculated the thermoeconomic changes caused by the back pressure changes in the high back pressure heating operation method and the dual unit combined heating operation method,and pointed out that there is an optimal back pressure point with the best thermoeconomic.