LNG接收站试运投产工艺改进及应用

Improvement and application of trial operation technology for LNG receiving terminal

LNG接收站是中国接收进口LNG资源的重要中转站,但目前仍存在试运投产成本高、物料消耗大、试车时间长等问题。为此,以国家管网集团深圳天然气有限公司LNG接收站试运投产为例,对低温管道预冷及填充、LNG储罐预冷及BOG系统试车4个流程进行了工艺改进,并开展了试运投产实践应用,结果表明:利用液氮对低温管道预冷可实现卸料总管、码头保冷循环管道、LNG低压输出管道的同步预冷和填充,并可对预冷卸料总管后的氮气进行二次利用;对先预冷好的储罐进行小流量卸料的同时,即启动下一个储罐的预冷,可实现两个储罐预冷完成后同时全速卸料;改进后的工艺实现了试运投产物料消耗有效降低、节约了试车成本,同时缩短了试运投产时间,保障了试运投产过程安全。研究成果可为保障LNG接收站试运投产安全、平稳、高效进行提供实践参考。

LNG receiving terminal,as an important transfer station for China to receive imported LNG resources,still has problems such as high trial operation costs,large material consumption and long trial operation time.In response to this,technology improvement was implemented in the four processes of pipeline precooling,unloading pipeline flling,tank precooling and BOG system trial operation based on the trial operation of the LNG receiving terminal of PipeChina Shenzhen Natural Gas Co.Ltd.,and the trial operation technology was applied practically.The results show that:pipeline precooling with liquid nitrogen could realize the precooling and flling of the unloading pipeline,the wharf circulation pipeline for cold insulation and the low-pressure LNG export pipeline at the same time,and the nitrogen can be recycled after precooling the unloading pipeline.Besides,the precooling of the next tank can be started while the first precooled tank is unloaded at a small flow.Thus,the two precooled tanks can be unloaded at full flow simultaneously.In addition,the improved technology optimization method effectively reduces the material consumption of trial operation,saves the trial operation cost,and shortens the time for trial operation,thereby ensuring the safety of trial operation.Generally,the research results could provide a practical reference for the safe,stable and eficient trial operation of LNG receiving terminals.