| Description |
The study of the rheological properties and deposition potential of organic mixtures such as petroleum are explored below the initial wax appearance temperature using a recycled flow loop, an active slurry-making device called the Scraped Exchanger, and a model oil made with mineral oil, paraffin wax, and LVGO wax. Sub-WAT (heterogeneous) oils, when flowed under isothermal (ambient and oil temperatures are the same) and non-isothermal conditions exhibit no deposition and greatly reduced deposition when compared to similar thermal gradients in above-WAT (homogeneous) oils, respectively. Heterogeneous oils form gels during shutdown just as with homogeneous oils, but the gel strength is greatly reduced (>50%) even with very little precipitated material (oil temperature at shutdown just below WAT). Solids content at shutdown appears to show little effect on subsequent gel strength. Particle size distributions measured using CantyVision equipment at shutdown also show little to no effect on subsequent gel strength, suggesting a balance between particle size and particle count, as well as a fundamental difference in gel matrix structure compared to homogeneous gels. In the ranges tested, all heterogeneous gels exhibited cohesive ("center-core") failure manifested as breakage occurring first within the gel instead of at the walls. Breakage patterns explored using laser particle imaging velocimetry. |
