非补燃余热锅炉变工况性能计算模型及分析

余热锅炉的变工况性能对联合循环机组的安全经济运行有较大的影响。以具有整体除氧器的单压余热锅炉汽水系统为例,建立了余热锅炉过热器、蒸发器和省煤器设计工况和变工况的数学模型,给出了计算程序框图,得到了余热锅炉设计工况和变工况下的性能参数。结果表明:所建模型能够计算出变工况下余热锅炉汽水侧和烟气侧的参数;变工况下,非补燃余热锅炉的热端端差、节点温差和接近点温差主要受进口燃气温度的影响;余热锅炉的当量热效率主要受排烟温度的影响,降低余热锅炉的排烟温度是提高余热利用效率的主要措施。

Calculation and analysis model of off-design performance for heat recovery steam generator without supplementary firing

The performance of combined cycle is influenced greatly by heat recovery steam generator(HRSG).Take a single pressure HRSG with an integral deaerator as example,the design and off-design performance models of super heater,evaporator and economizer were built in this paper.The calculation program frame was given,and the calculation results of HRSG were obtained.The results show that the model built in the paper can calculate the parameters of gas side and steam side of HRSG.The thermal-end temperature difference,pinch point temperature,and approach point temperature are mainly influenced by HRSG inlet gas temperature.Heat efficiency of HRSG is mainly influenced by its exhaust temperature,which shows that decreasing HRSG exhaust temperature can enhance the recovery rate of waste heat.