利用LNG冷能的液化空气储能系统热力学分析

Thermodynamic analysis of liquefied air energy storage system by using LNG cold energy

为了降低传统液化空气储能系统(LAES)的能耗,同时实现液化天然气(LNG)冷能的最大化利用,将液化空气储能工艺与LNG再气化相结合,提出了一种新型深冷液化空气储能系统。利用Hysys软件对储能过程和释能过程进行了工艺流程模拟。模拟结果表明:系统在远距离输送(7 MPa)时,可实现137.82%的循环效率,能量容量为10.897 MW,[火用]效率为39.58%;系统[火用]损失主要发生在换热器上,占系统[火用]损失的64.5%。LNG的冷能用于联合液化空气储能和朗肯循环,具有较高的热力学性能,系统循环效率大幅高于常规的液化空气储能系统。

In order to reduce the energy consumption of conventional liquefied air energy storage systems(LAES) and to improve the use efficiency of the cold energy of liquefied natural gas(LNG),a new cryogenic LAES was proposed combining the air liquefied energy storage process with LNG regasification.The simulations of the energy storage process and the energy release process were carried out using Hysys.The simulation results show that the system can achieve 137.82% cycle efficiency with the energy capacity of 10.87 MW and exergy efficiency of 39.58% at long distance transfer(7 MPa).The main exergy loss occurs in the heat exchangers,accounting for 64.5% of the system exergy loss.By using LNG cold energy and the Rankine cycle for LAES,good thermodynamic performance is obtained and the system cycle efficiency is significantly higher than that of the conventional LAES.