Abstract:

This paper explores the source of boil off gas(BOG) at liquefied natural gas(LNG) receiving station and calculates the amount of BOG required to be treated. It is obtained that the amount of BOG required to be treated under unloading and non-unloading conditions is 15.837 t/h and 2.863 t/h, respectively. The composition of the BOG treatment system and the recondensation process are studied. Optimize the recondensation process and BOG treatment system by improving heat transfer efficiency of the recondenser, directly exporting low-pressure BOG, and controlling tank pressure. The parameters such as the amount of LNG required for BOG entering the recondenser, the liquid level of the recondenser and the pressure at the top and bottom of the recondenser are analyzed. The flow of LNG into the recondenser is adjusted by the regulator. The bottom pressure of the recondenser is controlled by adjusting the PV02A/B opening. The load of the BOG compressor is adjusted to adjust the liquid level of the recondenser to achieve the optimization of the liquid level control.

Key words: LNG receiving station, BOG treatment system, technology, control, tank pressure, recondenser

摘要：

分析了液化天然气(LNG)接收站蒸发气(BOG)的来源，对BOG需处理量进行了计算，得出：在卸船工况及非卸船工况下的BOG需处理量分别为15.837 t/h和2.863 t/h。研究了BOG处理系统的组成和再冷凝工艺，通过提高再冷凝换热效率、将低压BOG直接外输、控制储罐压力等方式，对再冷凝工艺及BOG处理系统进行了优化。分析了进入再冷凝器的BOG所需的LNG量、再冷凝器液位、再冷凝器顶部及底部压力等参数。利用调节器调整进入再冷凝器的LNG流量；通过调节阀门PV02A/B的开度控制再冷凝器底部压力；通过调节BOG压缩机负荷调整再冷凝器液位，实现液位控制的优化。

关键词: LNG接收站, BOG处理系统, 工艺, 控制, 储罐压力, 再冷凝器