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    耦合液化空气储能的LNG冷能集成发电系统性能分析及优化

    Performance analysis and optimization of LNG cold energy integrated power generation system coupled with liquefied air energy storage

    • 摘要: 为了提高液化天然气(LNG)冷能利用效率,并应对常规液化空气储能(LAES)系统循环效率、发电量、使用价值低以及LNG再气化过程的持续运行与能量存储过程的高峰操作不一致的问题,构建了耦合LAES的LNG冷能集成发电系统,对系统进行了热力学性能与经济可行性的评估。研究结果表明:以Ethane和Propane作为回热式有机朗肯循环(RORC)的循环工质可显著提升系统性能;液态空气泵出口压力、液态空气储存压力、RORC中工质气化压力、RORC1冷凝器出口LNG温度和液化空气流量对系统性能有较大影响;基于遗传算法(GA)与非支配排序遗传算法(NSGA-Ⅱ)对系统性能进行单目标与多目标优化并对多目标优化结果进行决策,优化后系统的综合性能优于近年相关研究的系统;通过净现值(NPV)分析方法证明系统具有一定的经济可行性,系统净现值可达13.77×106 USD,系统的初始投资成本能够在12.55年得到回收。 研究成果为LNG冷能驱动的LAES集成发电系统的模型设计和高效运行提供了参考依据。

       

      Abstract: To increase the utilization efficiency of liquefied natural gas (LNG) cold energy and address the issues that the low round trip efficiency, power generation, utility value of conventional liquefied air energy storage (LAES) system and the continuous operation of LNG regasification process is inconsistent with the peak operation of the energy storage process, the LNG cold energy integrated power generation system coupled with liquefied air energy storage was built. Moreover, the thermodynamic performance and economic feasibility of the system were evaluated. The results showed that using Ethane and Propane as working fluids for reheat organic Rankine cycle (RORC) could significantly improve system performanc. The liquid air pump outlet pressure, liquid air storage pressure, the working fluids gasification pressure of the RORC, LNG outlet temperature of the RORC1 condenser, and the liquefied air flow rate had a significant effect on the system performance. The single objective and multi-objective optimization for the system performance were carried out based on the genetic algorithm (GA) and non-dominated sorting genetic algorithm (NSGA-Ⅱ), and the multi-objective optimization results were determined. The comprehensive performance of the optimized system was better than that of the system studied in recent years. The net present value (NPV) analysis method proved that the system had certain economic feasibility with the NPV reaching 13.77×106 USD, and the initial investment cost of the system could be recovered in 12.55 years. The research findings provide a reference basis for modeling design and efficient operation of the LAES integrated power generation system driven by LNG cold energy.

       

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