(304f) Influence of Hydrodynamics on BaSO4 Scale Deposition Kinetics on Steel Surfaces

Inorganic scale deposition affects the performance of heat exchangers, oil production lines, and geothermal wells as it lowers equipment lifetime, and impedes fluid flow. Deposition in tubing roughens the pristine surface properties resulting in a change in fluid hydrodynamics. Currently, there are very few published studies addressing turbulent deposition kinetics on complex surfaces.

In this paper, BaSO₄ scale deposition kinetics is investigated at turbulent conditions on roughened surfaces. Experimental studies were carried out in a custom-built once-through flow setup. The internal surfaces of deposition chambers were designed to mimic realistic surface roughness, with arithmetic mean heights S_a ranging from ~5µm to ~0.5 mm. Surface growth is characterized using a novel in-house code implemented in Python. Time-resolved x-ray computed tomography was used to visualize scale build-up. Sample effluents were analysed using inductively coupled plasma optical emission spectroscopy (ICP-OES) to estimate scale deposition rates. To link experimental results to the changes in flow characteristics, a computational fluid dynamics (CFD) model is employed using large eddy simulation (LES) for turbulence modelling and a custom Debye-Hückel base implementation of scale deposition.

Reinforced by the CFD model, scale deposition will be linked to the hydrodynamics, imposed by the changing wall properties on the turbulent flow.