摘要
大型汽轮机组采用高背压方式供热可以充分利用乏汽余热,提高燃料利用效率,已经有越来越多火电厂进行高背压供热改造。为确保高背压机组运行经济性,针对某电厂330 MW高背压热电联产机组建立Ebsilon模型并进行全工况模拟,根据低压缸最小冷却流量确定了机组的理论负荷区间,针对其实际热负荷条件建立了热网数学模型,结合热网供回水温度分析其在不同环境温度条件下的背压运行方式和电负荷范围,确定了优化背压后机组的实际运行边界;并针对热网回水偏离理想值时的经济性进行分析,确定了机组高背压投运策略。结果表明:机组采用高背压乏汽余热供热方式可以有效提高供热能力约80 MW,但是其环境温度适应性较差,环境温度较高时,采用抽背方式供热的经济性要明显优于抽凝方式,采用优化后的背压运行方式最高可降低标准发电煤耗约34 g/kW·h;另外,热网回水温度严重影响高背压机组的经济性,在不同的供水温度下,其高背压投运的边界回水温度也相应改变。
Using high back pressure heating mode for large steam turbine units can make full use of waste heat of exhaust steam and improve fuel utilization efficiency.Thus,more and more thermal plants have carried out high back pressure heating transformation.In order to ensure the operation economy of high back pressure unit,Ebsilon model was established for 330 MW high back pressure cogeneration unit to conduct simulation under all working conditions.Secondly,we calculated the theoretical load range of the unit according to the minimum cooling mass flow of LP cylinder and established the mathematical model of the heat supply network according to its actual heat load conditions.Then,combined with the supply and return water temperature of heat supply network,we analyzed the back pressure operation mode and electric load range at different ambient temperatures and determined the actual operation boundary of the unit after the optimization of back pressure.We analyzed the economy of the return water of heat supply network deviating from the ideal value to determine the high back pressure operation strategy of the unit.Results show that the high back pressure waste heat of exhausted steam heating mode can improve the heating capacity by about 80 MW,but its environmental temperature adaptability is poor.When the ambient temperature is high,the economy of high back pressure heating is better than that of extraction condensate mode.The optimized back pressure operation mode can reduce the coal consumption of standard power generation by about 34 g/kW[DK]•h.In addition,the return water temperature of heat supply network seriously affects the economy of high back pressure units:at different water supply temperatures,the return water temperature of boundary of high back pressure operation changes accordingly.
作者
李健
丁维栋
杨志平
王宁玲
戈志华
LI Jian;DING Weidong;YANG Zhiping;WANG Ningling;GE Zhihua(National Thermal Power Engineering&Technology Research Centre,North China Electric Power University,Beijing 102206,China;Inner Mongolia Jingning Thermal Power Co.,Ltd.,Ulanqab 012000,China)
出处
《华北电力大学学报（自然科学版）》
CAS
北大核心
2023年第4期101-111,共11页
Journal of North China Electric Power University：Natural Science Edition
基金
国家重点研发计划项目(2020YFB0606202)。
关键词
热电联产
高背压供热
供回水温度
经济性分析
运行策略
cogeneration
high back pressure heating
supply and return water temperature
economic analysis
operation strategy
