基于Kalina循环的内燃机余热回收系统的热力学研究

Thermodynamic analysis of Kalina Cycle for Internal Combustion Engine Waste Heat Recovery

本文利用Kalina循环吸收内燃机(ICE)尾气余热,研究了ICE负荷、氨水浓度等关键参数对系统热力学性能的影响,并通过回收年限分析了系统的经济性。研究表明,较高的ICE负荷或氨水浓度可以改善系统性能;ICE常用负荷下,采用较低的透平入口压力可以获得更高的净输出功和热效率;ICE负荷或氨水混合物浓度越高,Kalina系统投资的回收年限越短,但如果ICE负荷小于25%,Kalina系统的回收年限将超过ICE的使用寿命。

The ICE-Kalina system,composed of a topping ICE and a bottoming Kalina cycle with a superheater,is proposed in this paper.The effects of several important parameters on thermal and economic performance,such as the ICE percentage load,the turbine inlet pressure,and the ammonia mass fraction,are investigated.The net power output,the thermal efficiency of the Kalina cycle and the improvement of the thermal efficiency of ICE increase with the ICE percentage load and the ammonia mass fraction.A lower turbine inlet pressure leads to a higher net power output of Kalina cycle and a greater improvement of thermal efficiency.In the paper,if the same KC is used at different ICE loads,the payback period decreases with ICE load and ammonia mass fraction.In addition,both longer annual operation times and lower interest rates lead to shorter payback periods.However,it is worth noting that the payback period will be longer than the ICE’s lifetime if the ICE load is low.