In a utility boiler, the most heat loss is from the exhaust flue gas. In
order to reduce the exhaust flue gas temperature and further boost the plant
efficiency, an improved indirect flue gas heat recovery system and an
additional economizer system are proposed. The waste heat of flue gas is used
for high-pressure condensate regeneration heating. This reduces high pressure
steam extraction from steam turbine and more power is generated. The waste
heat recovery of flue gas decreases coal consumption. Other approaches for
heat recovery of flue gas, direct utilization of flue gas energy and indirect
flue gas heat recovery system, are also considered in this work. The proposed
systems coupled with a reference 330MWe power plant are simulated using
equivalent enthalpy drop method. The results show that the additional
economizer scheme has the best performance. When the exhaust flue gas
temperature decreases from 153? to 123?, power output increases by 6.37MWe
and increment in plant efficiency is about 1.89%. For the improved indirect
flue gas heat recovery system, power output increases by 5.68MWe and the
increment in plant efficiency is 1.69%.
Thermodynamic Analysis For Performance Improvement of Power Plant By Flue Gas Heat Recovery System
