Process design, analysis, and optimization of an advanced liquid air energy storage system integrating organic Rankine cycle and light hydrocarbon separation driven by LNG cold energy

As the volume of international trade in liquefied natural gas (LNG) continues to rise, the enormous amount of cold energy released during the LNG regasification process has become an important secondary energy resource, and the liquefied air energy storage (LAES) is an advanced energy storage technology, but the electrical round trip efficiency (ERTE) and economic benefits of a standalone LAES system are low due to the lack of sufficient cold energy. Thus, this paper combines the LNG regasification process with LAES and couples organic Rankine cycle (ORC) and light hydrocarbon separation (LHS) to construct an innovative integrated system. The LNG high-grade cold energy is used for LAES and the excess electricity generated by renewable energy sources can be stored by the proposed system during off-peak hours, and the remaining cold energy is utilized by ORC and LHS. The ORC working fluid is selected based on environmental friendliness, safety, and thermodynamic matching characteristics. The effects of operating parameters on system performance are studied from thermodynamic, economic, and environmental perspectives. The system performance optimization based on the optimization algorithm is executed to make a trade-off between different performance evaluation indicators. The results indicate that the system after many-objective optimization has a higher NPV than the multi-objective optimization, and a net present value (NPV) of 1.170 × 10 9 USD is obtained, the unit environmental impact and the unit investment cost decrease to 4.84 mPts/GJ and 17.86 USD/GJ respectively, and an LNG cold energy utilization rate of 88.83% is achieved after optimization. The proposed system is demonstrated to be industrially feasible by performance evaluation based on 5E analysis and provides a promising solution for the efficient utilization of LNG cold energy.