Kinetics of Waxy Gel Formation from Batch Experiments

In spite of its importance, wax deposition is still not fully understood, and a reliable physical description of wax deposition is still to be agreed upon. Up to now, the focus in wax studies has been mainly on the radial transport of waxes to the cold wall through molecular diffusion, but other mechanisms that have been cited (and so far neglected) may count on the kinetics of deposit formation. An analysis of the experimental evidence is presented here, leading to the conclusion that an important role may be played by the axial convective transport and the oil gelation on the cold surface (i.e., by the bulk liquid-to-gel change driven by the temperature change). Gelation is faster than molecular diffusion and may lead to the formation of a loose solid network that is slowly filled by diffusion (by aging) in a successive step. An experimental apparatus has been employed to measure the gelation kinetics both on a model mixture and on a stock tank oil. Obtained data have been modeled by employing a classic...