基于热管换热器技术的炭素行业烟气余热回收利用的应用研究

Application research on flue gas waste heat utilization based on heat pipe exchanger technology in carbon industry

基于物料平衡理论,建立了炭素行业余热利用系统中理论空气量和理论烟气量的计算模型与方法,计算与验证了不同排烟氧量下的烟气量,并实现了烟气焓值的精确计算。针对炭素行业导热油炉系统排烟温度高(>400℃)而造成余热浪费的关键问题,基于能量梯级利用的原理,设计了基于热管换热器技术的烟气余热回收利用系统,将凝结水作为该系统冷源,降低了排烟温度,减少了汽轮机抽汽量,优化了炭素余热发电系统。某碳素厂通过应用该余热回收利用系统,可将排烟温度控制在180℃左右,年增发电量约为77万kW.h,节能效果显著。

Based on the material balance theory, the calculation model and method of theoretical air and flue gas volume were developed in the flue gas waste heat utilization system of carbon industry, and the flue gas volume at different oxygen contents was calculated and verified, and then the precise calculation of flue gas enthalpy was realized using the proposed model and method. Given the key problem that the high exhaust flue gas temperature of thermal oil furnace system produces much waste heat （more than 400℃）, a flue gas waste heat utilization system based on the heat pipe exchanger technology was designed based on the the- ory of energy gradient utilization. This waste heat utilization system uses the condensation water as cooling source to decrease ex- haust flue gas temperature, reduces extraction in turbine, and optimizes eogeneration system of carbon industry. This system has been applied in a carbon industry, in which case the exhaust flue gas temperature can be controlled under 180℃, and the increase of generating capacity is 0. 77 million kWh/a, showing remarkable energy-saving effect.