Dynamic Microscopic Study of Wax Deposition: Particulate Deposition
Gabriel Santos, Nagu Daraboina, Cem Sarica
Abstract
This study presents a continuing effort to unravel the wax deposition mechanisms using a state-of-the-art microscopic in situ visualization technique. The investigation focuses on understanding the effect of the flow rate on the particulate deposition mechanism. The existence of the particulate deposition mechanism is proven by the presence of wax crystals at a distance more significant than the mass transfer boundary layer thickness calculated from the film mass transfer theory, reinforcing that molecular diffusion is not the only one responsible for wax deposition. The flow rate study presents a direct relation between the flow regime and the particulate deposition mechanism. The lower the Reynolds number, the stronger this mechanism is observed. Under laminar and transition flow regimes, the deposit thickness and growth rate of the deposit are considerably greater than those calculated under the turbulent flow regime. The number of available crystals at the boundary layer for different flow rates is qualitatively analyzed. It is concluded that, under laminar and transition conditions, a larger number of crystals is available for deposition compared to turbulent cases. This effect can be explained by the larger induced shear forces on the flow at higher Reynolds numbers.