Kalina循环是一种广义的混合工质Rankine循环,对其热力学性能相比于传统Rankine循环的改进程度历来是研究的重点方向。文中综述了前人的评价准则,并提出新的评价方法和公平的比较基准,构建了氨-水混合工质的Rankine循环和Kalina循环,模拟并评价了2个循环,结果显示,Kalina循环比Rankine循环热功转化率高3.3个百分点,产功量高出19.5%,火用效率高出6.6个百分点。循环机制分析表明,由于动力子循环和吸收子循环的耦合作用,使得Kalina循环的透平背压更低,与冷凝水的温度匹配更好,温度和浓度得到更合理的梯级利用,系统热力学完善度更高。文中揭示了Kalina循环与Rankine循环的关键差异以及Kalina循环机制,可作为中低温余热动力循环的设计参考。
Kalina cycle is a kind of generalized Rankine cycle with mixed working fluid. Researchers have put so much attention on the improvement of thermodynamic performance between Kalina cycle and traditional Rankine cycle. This paper summarized the existing evaluation criteria and proposed a new and more equitable criterion. Using ammonia-water as working fluid, this paper simulated and assessed the power cycles and analyzed the thermodynamic performance with ASPEN PLUS. The result shows that comparing with Rankine cycle, Kalina cycle is 3.3% higher of thermal efficiency, 6.6% higher of exergy efficiency, and 19,5% higher of work production. By coupling of power sub-cycle and absorption sub-cycle, the analysis of cycling mechanism of Kalina cycle shows that the cycle has lower pressure in the outside of the turbine, and the working fluids can match more reasonable with the cooling water according to the coupling between power sub-cycle and absorption sub cycle. The temperature and concentration can be utilized more reasonable. Comparing with the Rankine cycle, Kalina cycle improved the thermodynamic perfectness. This paper announces the key differences between these two cycles and the mechanism of Kalina cycle, and it can be referenced in designing of waste-heat power cycle with mid-low temperature heat source further.