600MW超临界火电机组给水回热系统改造及分析

Analysis and modification of 600MW super-critical thermal power unit's feed-water heat recovery system

国内现役一次再热燃煤机组的回热系统性能还有提高的空间,主要表现在机组的第三段抽汽具有超高的过热度,导致换热温差过大以及能级利用不合理,使不可逆损失的增大。当前较为普遍的改造措施即采用外置式蒸汽冷却器,降低换热器设计压力,通过提高回热效率提高机组总体发电效率。本文基于某燃煤电厂600MW的超临界机组,对于可提高机组回热效率的技改措施及热经济性进行综合分析,为汽轮机设计及现役机组的改造提供重要理论依据。

The performance of domestic coal fired units’ single reheat system also has space to be improved. Main reason is that the third section steam extraction of the unit has super high superheat, resulting in excessive heat exchange temperature difference and unreasonable utilization of energy level, and resulting in the increase of irreversible loss. The current reform measures more common with outside steam cooler, and lower pressure heat exchanger design, to improve the thermal efficiency by improving the efficiency of power generation units in general. Based on 600 MW the supercritical unit of a coal-fired power plant, the comprehensive analysis of the technical improvement measures and the thermal economy of the unit can be used to improve the efficiency of the unit, which could provide important theoretical basis for steam turbine design and retrofit of units.