Large coal consumption and low unit efficiency are common issues in China's current power plants.Generally

adding waste-heat utilization system in rear gas flue of boilers is an important way to solve this problem.Taking a domestic ultra supercritical 1 000 MW unit as the example

thermodynamic calculation and exergy analysis of the conventional waste heat utilization scheme and the new parallel connection waste heat utilization scheme were conducted.Moreover

comprehensive comparison between the above two schemes was carried out.The results show that

compared with the conventional waste heat utilization scheme

the net coal consumption rate reduction of the new parallel connection waste heat utilization scheme rose from 1.80g/(kW·h)to 3.62g/(kW·h)

reducing exergy loss of 5.4MW during the air preheating

improving the exergy efficiency of the air preheater from 78.3%to 85.0%.To sum up

the new parallel connection waste heat utilization scheme dramatically increased the unit efficiency and had great energy-saving effect.