液化天然气(LNG)接收站蒸发气(BOG)压缩处理工艺中,滴液或重组分在BOG低压机入口过滤器滤网上凝结,导致压差升高甚至触发压缩机跳车;低压机与高压机串联操作时负荷匹配性差,极易引发压缩机频繁跳停.针对上述问题,以某LNG接收站为例,通过理论及模拟计算与现场运营经验相结合的方法,从工艺设计源头出发,对低压机入口分液罐工艺尺寸参数、低压机和高压机串联操作工艺进行了设计优化.其中,入口分液罐设计尺寸的工艺优化,提高了对BOG中携带的液滴或重组分的分离效果,避免了液滴或重组分在过滤器滤芯处富集导致的压差高报警或压缩机跳车;在串联的低压机和高压机之间增设具有一定缓冲时间的BOG缓冲罐,可有效平衡气体负荷变化,降低了两台压缩机串联操作的难度,减少了因负荷不匹配导致的频繁跳车.优化后,该接收站BOG处理系统长时间平稳运行.
In the liquefied natural gas(LNG)terminal,during the compression process of boil-off gas(BOG),dropping liquid or heavy components condense on the filter screen of the BOG low-pressure compressor inlet,resulting in increased pressure differential and even compressor tripping.The poor load matching between the low-pressure and high-pressure compressors in series operation can easily lead to frequent compressor trips.To address the above issues,taking a certain LNG terminal as an example,a method combining theoretical and simulated calculations with field operation experience was employed to optimize the design of the low-pressure compressor suction knock-out drum and the series operation process of the low-pressure and high-pressure compressors from the process design aspect.The process optimization of the suction knock-out drum design improve the separation efficiency of liquid droplets or heavy components carried in the BOG,avoiding high-pressure differential alarms or compressor tripping caused by the accumulation of liquid droplets or heavy components on the filter element.The addition of a BOG buffer drum between the series-connected low-pressure and high-pressure compressors,with a certain buffering time,effectively balances gas load fluctuations,reduces the difficulty of operating the two compressors in series,and decreases frequent tripping caused by load mismatch.After optimization,the BOG treatment system of this LNG terminal has been running smoothly for a long time.