Optimization of energy-exergy efficiencies of an advanced cold energy utilization system in liquefied natural gas filling station

In this study, a novel cold energy utilization configuration of liquefied natural gas is presented for liquefiedcompressed natural gas filling station by combining gasoline vapor recovery, power generation and blood freeze-drying. Aspen Plus software is employed for modeling, and the simulation results are compared with the published literature to verify the accuracy. Based on the analysis of gasoline vapor condensation temperature, when the condensation temperature is -30.2 degrees C, -59.8 degrees C and -114 degrees C in turn, the recovery efficiency can be guaranteed more than 95%, and the energy consumption is the most competitive. Subsequently, the influence of evaporator and turbine outlet pressure on the performance of the power generation subsystem is studied by thermodynamic analysis. Then, the genetic algorithm is applied to determine the optimal binary mixtures, and the optimization results exhibit that the maximum net power output and exergy efficiency reach 154.6 kW and 28.96%, respectively. Meanwhile, the equivalent output power of gasoline vapor recovery subsystem and blood freeze-drying subsystem are 139.14 kW and 305.53 kW, respectively. The economic analysis demonstrates that the design payback period is only 6.3 years, providing a new idea for reasonable utilization of cold energy in liquefied-compressed natural gas station.

Automated summary

The study presents a novel configuration for the utilization of cold energy in liquefied compressed natural gas stations, combining gasoline vapor recovery, power generation, and blood freeze-drying. Through optimization of temperature and pressure parameters, the study achieved high energy efficiency and competitive energy consumption performance.