针对国内已投产超超临界二次再热机组锅炉普遍存在再热汽温低的问题，对已投产的泰州电厂二期SG-2710/33.03-M7050型二次再热锅炉进行过热蒸汽和一、二次再热蒸汽的吸热量计算和分析，表明再热气温低的原因是受热面比例设计存在偏差。提出了烟气再循环的改造方案，在75%热耗保证（THA）工况采用5%烟气再循环率时，一、二次再热汽温可以达到610 ℃以上，50%THA工况采用15%烟气再循环率一、二次再热气温也可以接近600 ℃。

Ultra-supercritical units with secondary reheat cycle have been being in China.The reheat steam temperature of is often lower than design value,especially under rated load operation.In this paper,the low reheat steam temperature of the Taizhou Power Plant is discussed as an example,in which the double reheat boiler type is SG-2710/33.03-M7050.By comparing and analyzing the thermal absorptions of superheated steam and primary reheat steam and secondary reheat steam，it is determined that the inappropriate design on the proportion of heat-absorbing area is responsible for the low reheat steam temperature.An improvement scheme of using the flue gas recirculation to adjust steam temperature is put forward.With this proposed improment scheme of flue gas recirculation,the primary reheat steam temperature and secondary reheat steam temperature can be increased to over 610 ℃ for the 75% turbine heat acceptance condition (THA),and to nearly 600 ℃ for 50% THA condition.

TK227

国家重点研发计划（2017YFB0602200)