能量回收系统的热力学分析

THERMODYNAMIC ANALYSIS OF ENERGY RECOVERY SYSTEM

石油化工装置使用的能量由能量转换和能量回收两部分构成。能量回收系统起着减少供入能，降低能耗的重要作用。经分析提出了换热设备和换热网络损失计算方法，分析了传热温差对能量回收的影响，指出减少传热温差是减少过程损、提高能量回收率的重要途径；讨论了能量回收系统能量回收的限度及存在的热力学和经济两个限制点，经济限制点是技术经济优化的结果，是合成换热网络遵照的依据；最后，讨论了分析和夹点技术在节能中的作用及其关系。

The energy used in petrochemical unit stems from energy transfer and energy recovery. The energy recovery system plays an important role for reducing energy provision and minimizing energy consumption. This paper proposes a calculation method of exergy loss for heat exchangers and heatexchanging networks; analyses the effect of the temperature difference of heat transfer on energy recovery:points out that reducing the temperature difference of heat transfer is a path for decreasing the exergy lossand increasing the energy recovery; discusses the energy recovery limit and two limitations of thermodynamics and economics. The economical limitation is the result of the optimization of technology and economy, and it is also the principle for designing heat transfer networks. Finally, the functions and interactions of exergy analysis and pinch technology in energy conservation are discussed.