降低热网回水温度的钢厂余热回收供暖分析

Analysis of Waste Heat Recovery from Steel Plant for Heating by Reducing Return Water Temperature

余热回收供暖是实现节能减排和清洁供暖的重要手段。定量分析了降低热网回水温度对钢厂低品位余热回收率的影响,提出了基于降低热网回水温度的钢厂余热回收供暖系统,研究了系统内各余热回收单元及内部换热网络的确定原则,构建余热供暖系统等效性能系数(coefficient of performance,COP)作为系统性能评价指标,并以某钢厂为例确定了低品位余热回收流程及经济性。结果表明,当热网回水温度降低至15℃时,钢厂低品位余热回收率达100%;余热回收供暖系统等效COP为6.1;余热回收供暖系统使得一次热网供热能力达到798 MW;基于降低热网回水温度的钢厂余热回收供暖系统静态回收期约为4年,具有良好的经济效益。

Waste heat recovery for heating is an important means to realize energy saving,emission reduction and clean heating.The effect of low return water temperature of heating network on waste heat recovery rate for the steel plant was quantitatively analyzed.A waste heat recovery system for heating by reducing return water temperature was also developed.The principles was proposed to guide how to determine the internal heat exchange networks in each waste heat recovery unit.The equivalent coefficient of performance(COP)of the novel waste heat recovery heating system was introduced as the performance index.The whole low-grade waste heat recovery heating process was exemplified in a particular case study and its economic character was analyzed in detail.The results show that if the return water temperature of heating network decreases to 15℃,the low-grade waste heat recovery rate of the steel plant would reach up to 100%,and the equivalent COP is 6.1.Utilizing the waste heat recovery heating system increases the heating capacity of the primary heating network up to 798 MW.The static payback period of the waste heat recovery heating system for steel plant is 4 years,so it has good economic benefits.