Modeling multicomponent wax deposition and aging on cold surfaces with application to pipeline fouling

Abstract

AbstractA multicomponent model is developed for wax deposition onto a cold finger from a stirred wax‐containing oil. It utilizes Coutinho's thermodynamic equations for wax component concentrations and energy and mass transport equations within the deposit and from the oil and is the first cold‐finger model to predict both deposit thickness growth and aging by selective precipitation of heavier wax components. While it captures well deposit thickness growth, it requires preventing re‐dissolution of deposited wax to avoid shrinkage not observed in experiments. The model predicts deposit aging reasonably well but with quantitative deviations for the heavier wax of up to a factor of two. Possible explanations include the inadequacy of Hayduk‐Minhas and Cussler's hindered‐diffusion models to the soluble multicomponent wax diffusivities. Using pseudo two‐ and one‐component representation can reasonably predict the deposit thickness and aging of multi‐component deposits. This work shows an improved approach to modeling wax deposition and aging.