1000 MW机组锅炉余热利用方案对比

Comparison of different systems for waste heat recovery from flue gas in a 1 000 MW power plant

基于低温省煤器可有效回收锅炉尾部的烟气余热,提高机组效率,以某电厂1 000 MW机组为工程应用背景,根据能源梯级利用原则,优化烟气余热利用系统,提出了4种不同的余热利用方案。利用矩阵法,计算得到各方案的汽耗降低值。通过对比分析,相对于低温省煤器布置于空预器出口的传统方案,采用空预器烟气旁路的方案,可使得供电煤耗降低值由1.85 g/k Wh提高至3.14 g/k Wh,机组节能降耗效果显著。

To recover the waste heat from flue gas and lower the temperature of the flue gas, four systems are proposed by using a low tem- perature economizer for energy saving based on the energy cascade utilization principle in a 1 000 MW power plant. The efficiencies of these systems are obtained by using the matrix method. Comparing the typical system of waste heat recovery that the economizer is located after the air preheater ;the system of flue gas bypass of the air preheater has advantages and the standard coal consumption reduction is in- creased from 1.85 g/kWh to 3.14 g/kWh.