特稠油停输与再启动方案探讨

Discussion on the Shutdown and Re-startup Programs of Extra Heavy Oil

基于国内某长距离特稠油管道和4种不同掺柴油比掺混稠油,利用瞬态流体仿真软件SPS,计算和评估了自启动、大掺柴油比掺混稠油置换启动、热柴油顶替启动和临时补救—置换—再启动4种启动方法,得到启动过程中重要参量的变化情况和各再启动方案在输送不同油品时的适应性。研究表明:停输后临时补救—置换—再启动方法适应性最强,可以适应于较大时间范围(如72 h)的停输与再启动;自启动和大掺柴油比掺混稠油置换启动的最大停输时间相同,对小掺柴油比的掺混稠油最大停输时间不足72 h;黏度较小的大掺柴油比掺混稠油宜自启动,黏度较大的小掺柴油比掺混稠油适于以大掺柴油比掺混稠油置换启动;热柴油部分顶替启动效果最差,最大停输时间最小。同时,给出了给定掺柴油比掺混稠油在不同停输时间下的再启动推荐方案,为同类型管道的停输再启动提供技术支持和借鉴。

In this paper,one domestic long-distance extra heavy oil pipeline and heavy oil blended with diesel in four blending ratios were analyzed. First,four startup methods were calculated and evaluated by using the transient fluid simulation software SPS,including self startup,replacement startup of heavy oil blended with diesel in high blending ratio,displacement startup of hot diesel and temporary remedy-replacement-re-startup. Research results show： when the safety risk,startup time and operation complexity are taken into consideration comprehensively,the temporary remedy-replacement-re-startup method after the shutdown is the best in adaptability. It is adaptable to the shutdown and re-startup in larger time range（ e.g. 72 h）,and also applicable to scheduled shutdown and unexpected shutdown. The maximum shutdown time of self startup is equal to that of replacement startup of heavy oil blended with diesel in high blending ratio,and their maximum shutdown time for heavy oil blended with diesel in low blending ratio is less than 72 h. Low-viscosity heavy oil blended with diesel in high blending ratio shall be started by means of self startup,and high-viscosity heavy oil blended with diesel in low blending ratio shall be started by means of replacement startup of heavy oil blended with diesel in high blending ratio. Partial displacement startup of hot diesel is the worst and its maximum shutdown time is the shortest. And finally,the recommended re-startup programs for heavy oil blended with the diesel in the given blending ratio under different shutdown time were provided. They provide the technical support and reference for the shutdown and re-startup of other pipelines of the same type.