The flow of waxy or paraffinic crude oils in a pipeline could be shutdown for a variety of reasons, resulting in their cooling and subsequent gelling. Gel formation from a multicomponent wax‐solvent mixture during flow shutdown was investigated experimentally and analyzed with a transient heat‐transfer model based on the moving boundary problem formulation. The gelling experiments were performed with a 0.10 g/g wax‐solvent mixture in a flow‐loop apparatus, following the formation of a steady‐state deposit layer in turbulent flow regime, at two initial wax‐solvent mixture temperatures, with a constant coolant temperature, and for different shutdown times. The gel formation was found to be a fast process, which continued until the gel fully occupied the deposition tube. Gas chromatographic analyses of the deposit samples (under sheared cooling) and the gel samples (under static cooling during flow shutdown) indicated significant differences in the composition and the total wax content. The deposit samples showed an enrichment of heavier paraffins, whereas the composition of gel samples was comparable to that of the original wax‐solvent mixture. The predictions from the transient model showed that a lower initial oil temperature, a lower coolant temperature, and a smaller pipe diameter would result in a faster blockage of the pipe. The predictions from the moving boundary problem formulation agreed well with the flow shutdown data, which further confirmed that the solid and gel formation from wax‐solvent mixtures is modelled satisfactorily as a heat transfer process.

中文翻译：

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研究流量关闭期间“蜡状”石蜡混合物的胶凝行为

出于各种原因，可以停止管道中蜡状或石蜡质原油的流动，从而导致其冷却并随后发生胶凝。实验研究了多组分蜡-溶剂混合物在流量关闭期间的凝胶形成，并基于基于移动边界问题公式的瞬态传热模型进行了分析。在0.10 g / g蜡-溶剂混合物在流动回路装置中进行胶凝实验后，在两个初始蜡-溶剂混合物温度下，在恒定的冷却剂下，在湍流状态下形成稳态沉积层温度，以及不同的关机时间。发现凝胶形成是快速的过程，其持续直到凝胶完全占据沉积管。沉积物样品（在剪切冷却下）和凝胶样品（在流量关闭过程中在静态冷却下）的气相色谱分析表明，组成和总蜡含量存在显着差异。沉积物样品显示出较重的石蜡富集，而凝胶样品的组成与原始蜡-溶剂混合物相当。瞬态模型的预测表明，较低的初始油温，较低的冷却液温度和较小的管道直径将导致管道堵塞更快。移动边界问题公式的预测与流量关闭数据非常吻合，该数据进一步证实了蜡-溶剂混合物形成的固体和凝胶形成的传热过程令人满意。