Abstract:

The recondensation system of boil-off gas (BOG) in LNG (liquefied natural gas) receiving terminal is simulated with software PRO/Ⅱ8.0 aiming to reduce its high energy consumption, and the key process parameters such as the change of the output of LNG, the mass ratio and the BOG temperature are analysed. An optimized process, named the precooling of BOG, is proposed, in which the sub-cooled high pressure LNG is used to cool the BOG from the compressor before it enters into the recondenser aiming at reducing the compression ratio of BOG compressor. The optimized process can save the work of BOG compressor in 32.5% compared with the existing process and can improve the operation flexibility when the downstream system of gas transportation appears fluctuation in gas load between peak and valley. Therefore, the proposed process has better performance for peak-valley adjustment.

Key words:

液化天然气, 蒸发气体, 再冷凝, 工艺优化, 压缩, 能耗

摘要：

针对液化天然气（LNG）接收站的蒸发气体（BOG）再冷凝工艺系统能耗偏高的问题，对现有BOG再冷凝系统进行了工艺流程优化。通过对BOG压缩机入口温度、BOG压比及物料比等影响BOG再冷凝工艺能耗的主要运行参数的分析，提出了利用高压LNG预冷增压后的BOG，降低BOG压缩机压比的工艺流程。优化后的BOG再冷凝工艺较原工艺可节约BOG压缩机能量消耗32. 5％，且优化后的流程改善了LNG下游管网输气峰、谷负荷波动时的操作弹性，有较好的调峰功能。

关键词:

液化天然气, 蒸发气体, 再冷凝, 工艺优化, 压缩, 能耗