螺杆膨胀机双循环低温余热回收系统分析  

Analysis of Dual-Cycle Low-Temperature Waste Heat Recovery System with Screw Expander

作　　者：曹滨斌[1] 李惟毅[1] 

机构地区：[1]天津大学机械工程学院,天津300072

出　　处：《天津大学学报》2010年第4期309-314,共6页Journal of Tianjin University(Science and Technology)

摘　　要：针对100.℃以下流体的余热回收,建立了采用低沸点工质的双循环螺杆膨胀机余热回收系统优化模型,根据工质在蒸发器出口的热力状态不同,对不同膨胀过程求解,并分析了影响系统性能的主要因素.结果表明:对于工质蒸发温度的选择,当可以忽略蒸发侧泵耗时,宜采用以机组效率最大为目标进行优化设计,当必须考虑蒸发侧泵耗时,宜采用以系统效率最大为目标进行优化设计;对于螺杆膨胀机膨胀比的选择,当余热温度<100℃时,工质R245fa的最佳膨胀比为4,丁烷的最佳膨胀比为3,当余热温度>100℃时,最佳膨胀比的值增大;对于循环工质的选择,应考虑单位质量做功能力强、蒸发压力低和最佳膨胀比小的有机物等.An optimizing model of dual-cycle low-temperature waste heat recovery system using screw expander was proposed in this paper. In this analysis, the working fluids were below boiling temperature, and the heat resource was waste thermal fluid below 100℃. According to the thermal states of working fluids at the evaporator outlet, the factors affecting the system performance were analyzed through calculations in different expanding processes. The results show that as for the option of evaporate temperature, when power consumption of the pump at evaporator section can be neglected, the optimal design aims at the maximum of expander efficiency; when the power consumption can not be neglected, the optimal design aims at the maximum of the system efficiency; as for the option of expansion ratio, when waste heat source temperature is below 100 ℃, the optimal expansion ratio of the working fluid R245fa is 4, that of the working fluid butane is 3; when waste heat source temperature is above 100 ℃, the optimal expansion ratio increases; as for the option of working fluid, some organic matter with low evaporating pressure and low optimal expansion ratio while with strong working capability per unit mass needs to be considered to adopt. The conclusions provide references for the fuither engineering applications.

关 键 词：螺杆膨胀机 双循环 低沸点工质 余热回收 

分 类 号：TK11[动力工程及工程热物理—热能工程]