燃煤含碳量波动瞬态过程电站锅炉 分析

Coal quality variation affects the control system performances and energy efficiency of coal-fired power unit, and the carbon content variation is a main type of coal quality variation. On the basis of the second law of thermodynamics, the distribution of energy losses in the transient processes under coal carbon content variation is studied, and exergy conversion coupling mechanism among boiler heat transfer devices is explored. The research shows that the combustion exergy loss accounts for 57.77% of the total exergy loss of the boiler in steady-state operating condition, and the change of combustion exergy loss accounts for the biggest portion of total exergy loss change under carbon content variation. During the transient processes with step change of coal carbon content, the exergy loss of water wall heat transfer has the most significant change, while the most significant change in exergy efficiency is on the low-temperature superheater, and the change rates of heat transfer equipment exergy loss and exergy efficiency tending the steady state get slower along fluegas flow.