Proposal and parametric analysis of an innovative natural gas pressure reduction and liquefaction system for efficient exergy recovery and LNG storage

• Published in: Energy (Oxford) Vol. 223; p. 120022
• Main Authors: Li, Chenghao, Zheng, Siyang, Chen, Yufeng, Zeng, Zhiyong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.05.2021; Elsevier BV
• Subjects: Compression; Compression ratio; Exergy; Exergy recovery; Gas pressure; Gas transmission; Liquefaction; Liquefied natural gas; liquids; LNG storage; Mass flow; Natural gas; Parametric analysis; Parametric statistics; Pressure; Pressure reduction; Pressure reduction station; Recovery; Refrigeration; supply chain; Supply chains; Thermodynamic analysis; Thermodynamics; Thermodynamic analysis; Pressure reduction station; Liquefaction; Exergy recovery; LNG storage; Natural gas
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2021.120022

Worldwide concerns for fuel shortage and environmental problems call for efficient exergy recovery of industrial processes, especially in energy-intensive industries like natural gas supply chain. Pressure reduction station is a key infrastructure for gas transmission, where feed gas reduces its pressure with specific equipment. However, a great deal of exergy is wasted using conventional pressure regulation methods. In this paper, an innovative natural gas Pressure Reduction and Liquefaction System (PRLS) is proposed for efficient exergy recovery and liquefied natural gas (LNG) storage. The idea is to recover high-quality exergy of feed gas by producing LNG which makes full use of the thermodynamic exergy generated from the isentropic expansion. In this way, the PRLS needs no extra energy and becomes bifunctional (pressure reduction, LNG production and storage). Two system configurations are considered and thermodynamic performances are investigated under different system parameters and feed gas conditions. Results show that the maximums of liquid yield rate and exergy efficiency are 23.1% and 66.7%, respectively. The performances are subject to compression ratio and refrigeration mass flow, as well as feed gas conditions. The simplicity, flexibility, and efficiency make PRLS a good option for exergy recovery for PRS and distributed LNG production. •Propose a bifunctional system for natural gas pressure reduction and liquefaction.•The simply-designed system has obvious technical feasibility and good performance.•The maximum liquid yield rate and exergy efficiency are 23.1% and 66.7%.•A parametric analysis is conducted to illuminate the effects of different parameters.