Load response characteristics of 350 MW cogeneration CFB unit
In recent years,the proportion of cogeneration units in coal-fired units has increased,and thermal power generation has gradu-ally assumed the heavy responsibility of peak regulation,and the demand for flexibility has increased.Combined heat and power circulating fluidized bed(CFB)units can use boiler steam-water side and heat network heat storage to improve the rapid variable load capacity of the unit,so a quantitative calculation method for steam-water side heat storage and heat network heat storage of supercritical cogeneration CFB units was proposed.Taking a 350 MW cogeneration CFB unit as an example,the working fluid flow on the steam-water side of the unit and the steam extraction and circulating water of the heat network were analyzed.The heat storage coefficient Csw and the heat network heat storage coefficient Ch were calculated under different load conditions(35％～90％)by combining the design parameters and historical operation data of the unit,and the load response characteristics of the unit and the sustainable time of heat storage utilization were further analyzed.The results show that with the increase of the load of the unit,the heat storage coefficient Csw of the steam-water side increases,and the Csw of the steam-water working fluid changes greatly in the high load stage of the unit,while the heat storage coefficient Ch of the heat network is almost unchanged.The sustainable time of heat storage utilization of the unit is directly proportional to the load of the unit and inversely proportional to the variable load rate of the unit.The sustainable time of heat storage utilization of heat network is greater than that of steam and water side,and the heat storage capacity of heat network almost does not change with random group load changes.At the variable load rate of 4％/min,the heat storage utilization of the heat network can last for about 285 s,while the heat storage utiliza-tion on the steam side can last for 161.5-249.7 s.The above calculation results can provide theoretical guidance for the deep peak regula-tion and rapid variable load operation of supercritical cogeneration CFB units.
万方数据
维普
