LNG接收站BOG处理工艺优化——以青岛LNG接收站为例  

A case study of processing and optimization of BOG gas treatment in an LNG terminal in Qingdao

作　　者：王小尚[1] 刘景俊[1] 李玉星[2] 多志丽[2] 王武昌[2] 

机构地区：[1]中国石化青岛液化天然气有限责任公司 [2]中国石油大学(华东)储运与建筑工程学院

出　　处：《天然气工业》2014年第4期125-130,共6页Natural Gas Industry

摘　　要：蒸发气(Boil Off Gas,缩写为BOG)的处理是LNG接收站必须考虑的关键问题之一,关系着LNG接收站的能耗及安全、平稳运行。为此,介绍了LNG接收站BOG处理的4种工艺:①BOG直接压缩工艺;②BOG再冷凝液化工艺;③BOG间接热交换再液化工艺;④蓄冷式BOG再液化工艺。运用HYSYS软件建立了采用不同BOG处理工艺的LNG接收站模型,对比了目前主要采用的BOG直接压缩工艺和再冷凝液化工艺在工艺流程及能耗方面的差异,并分析了外输量、外输压力及再冷凝器压力对BOG处理工艺节能效果的影响,在此基础上提出了BOG再冷凝液化工艺的改进措施——BOG进入再冷凝器前进行预冷,可比原工艺节约18.2%的能耗。同时还针对青岛LNG接收站提出了BOG再冷凝液化及直接压缩工艺混合使用的优化运行方案,可使进入再冷凝器的LNG流量保持恒定,没被冷凝的BOG经过高压压缩机提压到外输压力,与完成气化的LNG混合后外输,可避免BOG进入火炬系统而造成的能源浪费,同时减小再冷凝器入口流量的波动,使装置运行更稳定、更经济。The BOG （Boil-Off Gas） processing system is one of the key issues relating directly to energy consumption and safe ＆ steady operation in an LNG terminal.Therefore,we introduced four processing systems for BOG treatment：direct condensation,recondensation,indirect heat exchange reliquefaction,and cooling storage reliquefaction.On this basis,we applied the HYSYS to build different LNG terminal models,simulated and compared the commonly used re-condensation process and the direct condensation in terms of process and energy consumption.And we also analyzed the impacts of the flow rate,pressure of send-out NG and re-con-denser pressure on the energy-saving results of BOG processing.Therefore,we recommended a further innovative measure for the re-condensation BOG process,i.e.,to precool the BOG before it enters the re-condenser,which can save the energy consumption by 18.2%.Meanwhile,we also presented an optimal operating scheme of mixing the above two processes for an LNG terminal in Qingdao.This can keep the LNG flow rate steadily entering the re-condenser,and the uncondensed BOG can be compressed to mix with the liquefied LNG,thus the BOG will be saved instead of entering the flare venting system,meanwhile,the flow rate fluctuation at the inlet of the re-condenser will be reduced to make the whole BOG processing more stable and cost-effective as a result.

关 键 词：LNG 接收站 BOG 直接压缩 再冷凝液化 间接热交换再液化 蓄冷式再液化 优化 混合运行 节能 

分 类 号：TE974[石油与天然气工程—石油机械设备]