高含硫气液混输管道在清管工况下的瞬态流动规律及优化设计

针对目前对高含硫气液混输管道清管工况瞬态流动规律认识不足,导致管道设计压力与终端段塞流捕集器尺寸不好确定的问题,以某高含硫气田为例,采用数值模拟方法,研究了清管过程中管道起点压力、管道终端排液量等参数的变化规律,分析了管内气相流速与原料气气液比对清管工况的影响,进而提出了高含硫气液混输管道设计压力与终端段塞流捕集器尺寸的优化确定方法:①当管内气相流速介于2~6m/s时,清管中管道起点压力超压现象不明显,清管时宜将管内气相流速控制在此范围内;②当管内气相流速或气液比减小时,清管中管道起点压力峰值和终端排液量均将增大,但不同管道的增大幅度并不一致,管道越长、高程差越大,其增加幅度越大;③在设计阶段,应根据管道运行后期可能会遇到的低管内气相流速与低气液比工况参数来确定管道合理的设计压力与段塞流捕集器尺寸。该成果可为高含硫气液混输管道的优化设计与清管操作提供依据。

Transient flow characteristics of the pigging process of high sulfur gas liquid mixed transmission pipelines and its significance to an optimal design of pipelines

The current research is insufficient on the transient flow characteristics of the pigging process of high sulfur gas liquid mixed transmission pipelines, which leads to the inconveniency of determining the pipeline design pressure and the size of a slug catcher. Taking some high sulfur gas liquid mixed transmission pipelines in service as instances, the variation rule of their running parameters including a pig′s running position and velocity, the start point pressure as well as terminal drainage volume of pipelines during the pigging process were studied by the numerical simulation method. The influences of the gas phase velocity and gas liquid ratio on the pigging process of high sulfur gas liquid mixed transmission pipelines were also discussed by numerical simulation. In addition, an optimal method was put forward to determine the pipeline design pressure and the size of a slug catcher. The results showed that (1) because the over pressure phenomenon at the starting point of a pipeline is not striking when the gas phase superficial velocity in the pipeline is 2 ~ 6 m/s, the gas phase velocity in the pipeline should be controlled within this scope; (2) the start point pressure peak and terminal drainage volume of pipelines would increase with the decrease of gas phase superficial velocity or gas liquid ratio, while the increasing degree in different pipelines is not consistent, i.e. the longer a pipeline or the bigger the elevation difference between the starting and terminal point of a pipeline, the greater the increasing degree will be; and (3) the pipeline design pressure and the size of a slug catcher should be determined based on the low gas phase velocity and low gas liquid ratio which may be encountered at the later stage of pipeline operation. The achieved conclusions and recommendations provide effective guidance for the optimal design and pigging operation of high sulfur gas liquid mixed transmission pipelines in the future.