水合物浆在管道中的流动安全

摘要：搭建了环境温度控制室，将直径为42mm，长为30m的不锈钢环道安置在其中。借助于实验环道分别进行了固相体积浓度为0～70％、平均流速为0.5～3.6m.s^-1的四氢呋喃水合物浆和HCFC-141b水合物浆的流动实验。发现管道中两种水合物浆的压降梯度随流速的增加而增加；而与水合物体积浓度的关系都存在一个临界值，分别为50.6％和37.5％，当体积浓度小于临界值时，水合物浆压降梯度随体积浓度的增加而很缓慢的增大；当体积浓度大于临界值时，压降梯度随体积浓度的增加而急剧增大。通过与其他研究的比较，以临界水合物体积浓度为判断标准定义了一个流动安全区，当管道中的水合物体积浓度小于临界值，可以认为是安全的，相反则认为管道存在水合物堵塞的威胁。

Flow assurance of hydrate slurry in pipeline

The flow assurance problem of pipelines in offshore production is becoming more and more serious because oil fields in more and more unusual environments have been brought in production.HCFC-141b and THF were selected as the substitutes to study the flow behavior and mechanism of hydrate blockage in pipelines on the newly built flow loop，which was a two pass loop consisting of a 42 mm diameter stainless pipe，30 m long.Slurry-like hydrates and slush-like hydrates were observed with the formation of hydrates in pipeline.There are critical hydrate volume concentrations of 37.5% for HCFC-141b hydrate slurry and 50.6% for THF hydrate slurry respectively.The pipeline would be free of hydrate blockage when the hydrate volume concentration was lower than the critical volume concentration; while otherwise the pipeline would be easily blocked.A safe region，which is defined according the critical hydrate volume concentrations，is firstly proposed for hydrate slurry，and it can be used to judge if the pipeline can be run safely or not.