Study on the Impact of Local Heating Combined with Deflection Agitation on the Conversion Efficiency of Gel Waxy Crude Oil in Storage Tanks

Résumé fourni par la source

Abstract To address the issues of extensive low-temperature dead zones and insufficient gelled-oil conversion efficiency associated with traditional heating methods in waxy crude oil storage tanks, this study proposes an improved scheme coupling localized concentrated heating with mechanical agitation at a specific deflection angle (45°). Distinct from previous passive heat transfer approaches that solely focus on improving the geometric structure of heating elements, this work reveals the mechanism of “spatial synergistic matching between flow paths and localized fixed heat sources.” By introducing an inclined impinging flow, the mechanical scouring and stripping effects of the fluid on the gelled oil at the side wall are enhanced, breaking the thermal resistance barrier formed by the extremely low thermal conductivity of the crude oil gel layer. This mechanism is systematically demonstrated by establishing a broad-temperature-range mathematical model that characterizes the nonlinear thermophysical property variations during the gel–sol transition of waxy crude oil, combined with computational fluid dynamics simulations and laboratory-scale experiments. Field synergy analysis confirms that, under the 45° deflection condition, the proportion of regions with a synergy angle below 90° reaches 19.41%, significantly improving the coordination between the velocity field and the temperature gradient field. Benefiting from this synergistic effect and the intense wall scouring, the gelled crude oil achieves nearly complete sol-state conversion within 4 h, with the final conversion rate leaping to 99.75%, overcoming the disadvantages of standalone tubular heating, which yields a conversion rate of less than 35% and severe edge accumulation. Furthermore, compared to traditional global heating, the novel coupled process reduces the energy consumption per unit temperature rise by 12.78%. This study provides a new theoretical perspective and engineering guidance for energy conservation and solidification response strategies in high-pour-point crude oil storage and transportation systems.

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