Study of Heat-Hydraulic Efficiency of Asphalt-Resinous Paraffinic Oil Deposits in Field and Trunk Pipelines

Abstract

The results of laboratory and numerical experimental studies of the thermal and hydraulic efficiency of a layer of wax deposits formed on the inner surface of the pipeline wall are presented. Measurements of the coefficient of thermal conductivity of wax samples of deposits taken from sections of existing main oil pipelines have been performed. To assess the effect of the sediment wax layer on the smoothness of the inner surface of the pipe wall, tests were carried out to determine the values of the roughness coefficient on samples of coils cut from sections of repaired main oil pipelines whose inner wall surface is covered with a layer of wax accumulated during their long operation and periodical pigging. The results of laboratory studies of the samples confirmed the relatively high thermal insulation properties and the smoothing capacity of the wax layer, and therefore, numerical experiments were also conducted to assess the effect of a formed wax layer on the heat and hydraulic regime mode of oil pipelines, including such parameters as the average kinematic viscosity of the flow, the final oil temperature, loss of pressure caused by the hydraulic resistance of the pipeline. Analysis of the results obtained in the course of mathematical modeling made it possible to evaluate the effective limits of the positive usage of a controlled oil wax layer as an internal thermal insulation coating for oil pipelines. Also, the paper discusses the effects of wax deposits on operational factors, such as the corrosion activity of the oil wax layer with respect to the inner surface of the pipeline wall metal.