大型燃气锅炉低温烟气冷凝余热梯级深度利用工程实测分析
Flue gas condensing heat cascade recovery measurement of large gas-fired boiler
摘要：
针对大型燃气锅炉低温烟气余热深度利用难题及严寒地区助燃空气温度低等问题，采用自主研发的防腐高效低阻烟气冷凝余热梯级深度利用技术回收2台70 MW大型燃气供热锅炉的余热。实测结果表明：额定工况下，锅炉排烟温度由172.2 ℃降至39.7 ℃，节能14.2%，以低热值计的天然气利用热效率为107.8%；部分负荷工况下，炉部排烟温度由129.1~157.7 ℃降至38.0~39.8 ℃，节能12.4%~13.4%，以低热值计的天然气利用热效率为106.7%；回收冷凝水95~157 t/d，明显减少了雾气排放；新增余热供暖面积18万m2；助燃空气被加热至40 ℃以上，避免了爆燃等问题；节能、节水、环保、经济效益显著。
Abstract：
In order to solve the problems of the deep utilization difficulty of low temperature flue gas-fired waste heat of large gas boiler and low temperature combustion air in severe cold zone, adopts the technology of flue gas condensing heat cascade recovery to recycle the waste heat from the flue gas of two 70 MW gas-fired boilers. The test results show that under the rated condition, the flue gas temperature is reduced from 172.2 ℃ to 39.7 ℃, the energy saving rate is 14.2% and the total thermal efficiency of the boiler system calculated by the low calorific value is 107.8%. Under the part load condition, the flue gas temperature is reduced from 129.1-157.7 ℃ to 38.0-39.8 ℃, the energy saving rate is 12.4% to 13.4% and the total thermal efficiency of the boiler system calculated by the low calorific value is higher than 106.7%. Meanwhile, the condensate water reaches 95 to 157 t/d, and the mist emission is effectively restrained. The new added heating area by waste heat reaches 180 000 m2. The combustion air is preheated to over 40 ℃ which avoids deflagration and improves the efficiency of the boiler. The energy conservation and environmental protection potential is great.
Keywords:gas-fired boiler, exhaust heat, depth recovery, cascade recovery, severe cold zone