Summary: | Wax precipitation affects the normal transportation of crude oil pipeline. Wax is generally removed by hot washing. Reducing energy of hot washing is the key to the security and energy-saving operation. It is necessary to reveal the heat transfer characteristics of the process. The melting characteristics of paraffin in the gathering and transportation pipeline are studied by numerical simulation in this paper. Mathematical model is established. Melting and flow characteristics of paraffin in gathering pipelines are researched. The effects of water temperature, size of spherical paraffin, and initial temperature on the central temperature and liquid phase ratio of the ball are analyzed. The melting stage is divided into informal melting stage and formal melting stage. The correlations between the dimensionless time Fo number, Ste number, Ra number, and subcooling degree Ci are proposed based on the dimensionless analysis. The correlation can be used to predict the complete melting time of paraffin in natural convection flow field. It is of guiding significance for hot washing.
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