1000 MW二次再热机组双机回热系统研究

Study on Double-turbine Regeneration System in 1000 MW Double-reheat Unit

对1000 MW超超临界二次再热机组的十二级回热系统方案进行研究,并对回热加热器进行㶲效率和㶲损系数的分析对比。结果标明,采用双机十二级回热系统能够大幅降低蒸汽再热后的回热加热蒸汽的过热度和平均换热温差,相比于高效十二级回热系统,整套高加系统的㶲效率均有所提高,特别是0号高加、2号高加、3号高加、除氧器、5号低压加热器的㶲效率提高约2%及以上,并能降低机组回热加热器的㶲损系数。同时,机组热耗可以降低20 kJ/kWh,可以节省0.73 g/kWh的煤耗,每年带来的经济收益超过280万元,经济效益提升明显。

This paper studies on the twelve stage regeneration system scheme of 1000MW ultra supercritical double reheat unit,compared exergy efficiency and exergy loss coefficient among double turbine regeneration system with high efficiency twelve stage regeneration system.The results show that double turbine regeneration could reduce the superheat of reheated steam and average heat exchange temperature difference greatly.Meanwhile the efficiencies of the whole set of high-pressure heater system is improved,especially the exergy efficiency of No.0 HP heater,No.2 HP heater,No3.HP heater,deaerator improved above 2%,and exergy loss coefficients are reduced.The heat consumption of the unit can be reduced by 20 kj/kWh,which can save about 0.73 g/kwh of standard coal consumption com-pared among double turbine regeneration system with typical twelve stage regeneration system in 1000MW ultra supercritical double-reheat unit.The economic benefit is significantly im-proved,which the annual economic benefit is more than 2.8 million yuan.