LNG船舶在航行过程中，由于储罐晃动、温度变化等原因会产生蒸发气（Boil-Off-Gas，BOG），导致LNG储罐超压，带来安全隐患，需对BOG进行再液化处理。针对目前大多数再液化系统采用单一预冷工艺导致系统能耗较高的问题，设计了一种新型双预冷工艺再液化系统以降低系统能耗。采用CO2和BOG双预冷工艺，并结合氮气逆布雷顿循环对BOG进行再液化，通过最小比能耗（SEC）评估系统能效。结果表明，双预冷工艺下BOG再液化系统的SEC为1.024 kWh/kgLNG，㶲效率为27.1%，相比CO2单一预冷工艺，系统总能耗降低超过20%。系统总成本分析显示，双预冷BOG液化工艺具有良好的经济效益。
During the voyage of LNG ships, evaporated gas (BOG) is generated due to heat leakage, swaying, etc., which leads to overpressure in LNG storage tanks, and BOG needs to be reliquefied. In response to the problem that most of the current re-liquefaction systems use a single pre-cooling process which leads to high energy consumption of the system, a new re-liquefaction system with dual pre-cooling process is designed to reduce the energy consumption of the system. A dual precooling process of CO2 and BOG, combined with a nitrogen reverse Brayton cycle for re-liquefaction of BOG, was used to evaluate the system's energy efficiency by means of minimum SEC. The optimisation results showed that the SEC of the BOG reliquefaction process was 1.024 kWh/kgLNG, with a exergy efficiency of 27.1%. The total system energy consumption was reduced by more than 20% compared to the CO2 single pre-cooling process. The total system cost was analysed and the results showed that the dual precooling BOG liquefaction process has good economic efficiency.
2025,47(18): 99-104 收稿日期：2024-11-19
DOI：10.3404/j.issn.1672-7649.2025.18.017
分类号：U665.1
基金项目：浙江省科技计划项目省级重点研发项目（2021C3184）；舟山市定海区重点研发项目（2023C1103）
作者简介：温小飞（1977 – ），男，博士，副教授，研究方向为船舶燃料供应系统
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