Flue gas condensing heat cascade recovery measurement of large gas-fired boiler
Ma Zhaokang, Wang Suilin, Mu Lianbo, Xiao Huipeng, Cheng Dongdong, Zhai Huixing, Wu Yadong, Shou De, Zhang Wei, Chen Yuping, Zhang Tong, Wang Shoujin and Meng Guangliang
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.