LNG卸船时预冷速度的控制要点

Control points of pre-cooling rate during LNG unloading

LNG接收站生产运行中的重点和风险点是LNG接卸船工作,卸船时预冷速度的控制甚为关键。国内外大多数LNG接收站的接卸经验并不是很成熟,预冷速度的控制经验相对缺乏,难于把握。基于某LNG接收站已接卸的LNG船的预冷数据,对LNG接卸时预冷速度的控制、影响与卸料过程中存在的安全操作等问题进行分析。在卸船过程中,预冷速度过快是引起卸料臂快速耦合器法兰处泄漏的重要原因;根据卸船安全性要求和接卸经验,目前该接收站预冷速度控制在2℃/min左右,对整个卸船过程影响较小,能有效避免或减少事故。

The focus and risk points in liquefied natural gas（LNG） terminal operation are LNG ship loading and unloading, especially the control of pre-cooling rate during LNG unloading. Most of LNG terminals on the world are not very experienced in loading and unloading, as well as control of pre-cooling rate. According to the available pre-cooling data of LNG ships in a LNG Terminal, the control and influence of pre-cooling rate during LNG loading and unloading and the operation safety in the unloading process are analyzed. In the unloading process, too high pre-cooling rate is a main reason for leakage at the flange of unloading arm quick coupler. According to unloading safety requirements and loading/unloading experience, the pre-cooling rate at the LNG Terminal is controlled at about 2 ℃/min, so that the entire unloading process is less affected and accidents can be effectively prevented or reduced.