利用LNG冷能的有机朗肯循环系统的工质研究和变工况性能分析

Analysis of working fluid and variable working conditions of organic Rankine cycle utilizing LNG cold energy

以LNG冷能和废热源驱动的有机朗肯循环可以提高系统的能源利用率。通过流程模拟软件HYSYS对使用不同工质的朗肯循环系统进行了模拟分析,结果表明,丙烷是用于低温朗肯循环最合适的工质。循环工质的蒸发温度高低对系统的净输出功及效率影响较为明显,废热烟气的流量或温度的提升有助于改善系统的性能。选定一个合适的冷凝温度,既能保证系统单位质量LNG所能输出的净功在一个合理的范围内,又可以改善系统效率。

An organic Rankine cycle driven by the cold energy of liquefied natural gas(LNG) and waste heat in exhaust gas was established to improve energy efficiency.Several organic Rankine cycles using different working fluids were simulated with the process simulator HYSYS.Results show that propane is the most suitable working fluid.The evaporation temperature of working fluid has a significant effect on net power output per unit mass of LNG and exergy efficiency.More exhaust gas flow rate and higher exhaust temperature can contribute to improve system performance.A suitable condensation temperature is necessary to ensure the net power output per unit mass of LNG in a reasonable range,and also can improve system exergy efficiency.