两级式低温烟气换热器运行效果评价  

Performance Evaluation on a Two-stage Low-temperature Gas-coolant Heater

作　　者：张瑞卿[1] 杨海瑞[1] 吕俊复[1] 

机构地区：[1]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《动力工程学报》2013年第8期613-618,共6页Journal of Chinese Society of Power Engineering

基　　金：国家科技支撑计划资助项目(2012BAA02B01);科技部资助项目(2011DFA60390)

摘　　要：在回热系统中布置低温烟气换热器(GCH)是降低排烟温度和回收热量的有效方式,将烟气换热器分别布置在1 000MW机组的电气除尘器前和脱硫吸收塔前,研究了烟气换热器投运后机组的性能.结果表明:两级式低温烟气换热器投运后,汽轮机热耗降低了0.56%,供电煤耗降低了1.59g/(kW·h),同时保证了烟气温度高于其酸露点温度,降低了相关设备的腐蚀风险;在保证脱硫效率的前提下,脱硫系统水耗降低了39.75t/h;电气除尘器的除尘效率有所提高,出口粉尘平均排放质量浓度降低到14.05mg/m3,能够满足新的国家排放标准要求;两级式低温烟气换热器有效地实现了机组节能、脱硫系统节水和电气除尘器除尘效率提高的目标,具有良好的应用前景.For heat recovery purposes, it is an effective way to set up a low-temperature gas-coolant heater in the waste heat recovery system so as to reduce the exhaust temperature of the flue gas. An evaluation was carried out to study the performance of a 1 000 MW unit, where a two-stage gas-coolant heater was arranged respectively in the upstream of its electrostatic precipitator （ESP） and flue gas desulphurization （FGD） absorber. Results show that after the gas-coolant heater being put into operation, the heat rate of steam turbine reduces by 0. 560/oo and the net coal consumption drops by 1.59 g/（kW · h）, when the gas temperature is kept to be above the acid dew pont, resulting in reduced corrosion risk of relevant facilities; meanwhile, the water consumption in FGD system decreases by 39.75 t/h, under the premise of a guaranteed desulphurization efficiency; simultaneously, with an increased removal efficiency of ESP, the average dust concentration at ESP outlet drops to 14.05 mg/m3 , which meets the requirements of the correspond- ing new national emission standards. The two stage low-temperature gas-coolant heater will have a bright prospect in application as its enhanced effect in energy saving of unit, water saving of FGD system and dust removal of ESP.

关 键 词：电站锅炉 余热利用 低温烟气换热器 脱硫系统 电气除尘器 

分 类 号：TK32[动力工程及工程热物理—热能工程]