从大系统的角度出发，为炼厂优化设计了全厂范围内的低温热系统，通过装置间的间接热联合，有效提高了低温热的利用率。通过详细设计和模拟计算低温热媒水网络的具体参数，有效回收利用92℃热媒458 t/h，回收热量达11.1 MW/h，该系统每月可为全厂节省低压蒸汽2 560 t。通过 GFDA3 效率分析评价对比，全厂低温热系统对热量的质量利用程度较高， GFDA3 效率可达0.865。

In the view of large scale system,a plant-wide low-temperature heat system is designed optimally for a refinery,which improves the utilization of low temperature heat through strengthening the heat integration among the units.Based on the detailed design and the simulation calculation of concrete parameters in the low-temperature hot medium water network,458 t/h of 92℃ hot medium water or 11 MW/h of low-temperature heat are recovered effectively.This system can help this refinery to save 2,560 t of low pressure steam per month.It is verified through analysis,evaluation and comparison on exergy that the plant-wide low-temperature heat system exhibits a higher efficiency in utilization of heat,with an exergy efficiency of 0.865.