LNG接收站储罐预冷工艺的优化

Optimization of LNG Storage Tank Cooling Process of LNG Receiving Terminal

LNG储罐预冷是LNG接收站调试投产过程中最关键和最危险的环节。本文结合接收站在不同建设阶段的调试方案,详细介绍了新建LNG接收站项目和扩建项目的储罐预冷工艺及存在的问题。对于如何高效回收预冷过程中产生的蒸发气,提出了用LNG储罐常温天然气置换氮气的方案。针对扩建LNG储罐项目中,新建卸料管道在预冷时可能存在的因法兰泄漏而导致储罐预冷中断的风险,提出了采用小口径管道进行储罐预冷的方案。优化方案成功应用于舟山LNG接收站二期的扩建储罐项目中,在实际应用中验证了优化方案的可靠性,对同类LNG项目具有借鉴意义。

Cooling of LNG storage tank was the most critical and dangerous work during the commissioning of LNG receiving terminal. Combined with the commissioning schemes in different construction stage of LNG terminal, the tank cooling process and existing problems of the new LNG terminal project and expansion project were introduced in detail. In view of the efficient recovery of the vaporized gas generated in the precooling process, a scheme of replacing nitrogen with normal temperature natural gas from LNG storage tank was proposed. In view of the risk of interruption of tank cooling due to flange leakage during cooling of newlybuilt unloading pipeline of expanded LNG storage tank project, a cooling scheme of using small-diameter pipeline to supply LNG was proposed. The optimization scheme was successfully applied in the phase II expansion project of Zhoushan LNG terminal, which verified the reliability of the optimization scheme in practice and had reference significance for similar LNG projects.