基于分液冷凝、多压蒸发非共沸有机朗肯循环流程设计及参数优化

Process design and parameter optimization of zeotropic organic Rankine cycle based on liquid-separation condensation and multi-pressure evaporation

有机朗肯循环具有结构简单、运行安全稳定的优点,但其推广应用受到高投资、低效率制约。对此,本文提出一种基于分液冷凝、多压蒸发的非共沸有机朗肯循环(LMZORC),建立了数学规划优化模型,并通过案例验证了新循环的优势。结果表明:与基本有机朗肯循环系统相比,LMZORC系统净输出功可提高5.05%~13.15%;分液干度对LMZORC系统的净输出功有重要影响,在所研究的工质中,都存在一个最佳的分液干度使系统净输出功最大;对于LMZORC系统,当温度滑移等于冷却水的温升,或者温度滑移小于冷却水的温升且工质温度滑移最大时,系统存在着最大净输出功;与不分液的多压蒸发系统相比,本文提出的多压蒸发组分调节系统能提高约2%的净输出功。

Organic Rankine cycle is characteristic of simplicity, safety and stability and so on. However, high cost and low efficiency are the main factors for impeding its application. This study proposes a zeotropic organic Rankine cycle（ORC） system based on liquid-separation condensation and multi-pressure evaporation（LMZORC）. Mathematical programming optimization model is established and the advantages of this new cycle are verified by case study. The results show that the net power output of the proposed LMZORC is 5.05%-13.15% higher than that of the basic ORC. In addition, the dryness of liquid-separation has a significant impact on the net power output of the LMZORC system. And in the studied working fluids, there is an optimal liquid-separation dryness to maximize net power output of the system. Furthermore, for the LMZORC system, when the temperature glide is almost equal to the temperature rise of cooling water, or the temperature glide is less than the temperature rise of the cooling water and the working fluid temperature glide is maximum, the maximum net power output can be obtained. Besides, the net power output of this proposed composition adjustment system with multi-pressure evaporation is nearly 2% more than that without liquid-separation. This study has initially validated the advantage of LMZORC, which has great value for the application of this cycle in the future.