摘要
为降低供热耗能,采用热泵回收烟气余热,可有效提高机组供热效率。以某300 MW亚临界CFB锅炉机组为例,分别在脱硫塔前后设置低温省煤器和烟气冷凝器,组成新型热泵供热系统,并建立该热泵回收烟气余热热力学模型,分析其烟气余热利用方式对热泵的热力学及供热性能的影响。计算结果表明,布置低温省煤器,设计工况下,热泵性能系数(COP)为1.746时,烟温由130℃降至90℃,可回收最大烟气余热20.87 MW,降低脱硫塔耗水量28.792 t/h;布置烟气冷凝器,可作为热泵低温热源,同时可回收烟气余热10.10 MW,回收冷凝水13.654 t/h。当热网回水温度升高时,COP降低,但热泵系统和供热系统的㶲效率均升高;当冷凝器出口水温升高时,COP和供热系统㶲效率降低,但热泵系统㶲效率升高。回收烟气余热的热泵供热方式,可有效利用烟气低阶能量且具有良好的节能节水收益。
To reduce heating energy consumption,using heat pumps to recover waste heat from flue gas can ef-fectively improve the heating efficiency of the unit.Taking a 300 MW subcritical CFB boiler unit as an exam-ple,a low temperature economizers and a flue gas condensers are set before and after the desulfurization tower to form a new heat pump heating system,a thermodynamic model for this heat pump recovery of flue gas waste heat was established to analyze the impact of flue gas waste heat utilization methods on the thermodynamics and heating performance of the heat pump.The results show that,a low-temperature economizers is arranged,un-der the design conditions,when the coefficient of performance(COP)of the heat pump is 1.746,the flue gas temperature decreases from 130℃to 90℃,which could as a high-temperature heat source of the heat pump,20.87 MW of waste heat can be recovered at most,and the water consumption of the desulfurization tower is re-duced by 28.792 t/h;A flue gas condenser is arranged,which can be used as a low-temperature heat source for the heat pump.At the same time,10.10 MW waste heat can be recovered,and 13.654 t/h condensed water can be recovered.When the return water temperature of the heating network increases,COP decreases,but the efficiency of the heat pump system and the heating system increases.When the water temperature at the con-denser outlet increases,the COP and heating system efficiency decreases,but the efficiency of heat pump system increases.It is shown that,the heat pump heating method of recovering waste heat from flue gas can effectively utilize the lower order energy of flue gas and has good energy-saving and water-saving benefits.
作者
白涛
靳智平
BAI Tao;JIN Zhiping(School of Electric Power,Civil Engineering and Architecture,Shanxi University,Taiyuan 030006,China)
出处
《电力学报》
2023年第2期117-126,共10页
Journal of Electric Power
基金
2019年度山西省重大专项资助项目(20181102010)。
关键词
煤电机组
CFB锅炉
亚临界
烟气余热
梯级利用
热泵
供热
热力学分析
coal-fired power units
CFB boiler
subcritical
flue gas waste heat
cascade utilization
heat pump
heat addition
thermodynamic analysis
