评估回热加热器热经济性的正确指标

在火电厂中 ,工程技术人员习惯用加热器的端差来评价回热加热器的热经济性。现今在大容量高参数机组的再热回热循环系统中 ,当装有独立的抽汽蒸汽冷却器的加热器或加热器具有内置式过热段时 ,该加热器的端差可能会出现负值。用热力学第二定律分析加热器的负值端差 ,将得到抽汽是被加热介质而给水是加热介质的错误结论。为此 ,对装有独立抽汽蒸汽冷却器或具有内置式过热段的回热加热器 ,建议采用加热器的传热系数和加热器有效度作为其经济性的评价指标

The Index to Correctly Evaluate Heat Economics of Regenerative Water Heater

In power plant,it is customary to evaluate the heat economics of regenerative water heater by its terminals temperature difference,but for regenerative water heater cycle system of moderm large capacity high parameter set,in which the regenerative water heater with separate draw out steam cooler or inner superheat stage is installed,the terminals temperature difference may be negative, if analysing with the Second Law of Thermodynamics, wrong result may be achieved that the draw out steam is heated matter and the feed water is heating matter. Thus for that heater, the heat transfer coefficient and the efficiency degree are suggested as the index to evaluate the economics of regenerative water heater.