Oil-mineral aggregate formation: effects of concentration and flow*

Multiphase flows are ubiquitous in various industries, and in nature. Dispersed oil droplets in these flows can capture sediment to form oil-mineral aggregates (OMAs). OMAs can be detrimental to industrial processes (e.g. buildup in pipes), but can also facilitate marine oil spill cleanup. While the formation of OMAs has been studied in some depth, it remains unclear how aggregation rate and aggregate properties vary with constituent concentrations and turbulence intensity. To begin to fill this gap, we aggregate oil and kaolinite clay at various concentrations via differential sedimentation in a cylindrical roller tank. After several hours, we measure the resulting size distribution of OMAs and quantify size, shape, and other properties. These results provide insight into formation rate and other environmentally impactful quantities such as settling/rising velocities. We also establish a baseline for studying the effects of turbulence intensity on OMA formation, presenting the design of a new experimental facility and procedure for investigating this problem. Our approach will enable a more detailed and definitive investigation of the formation rates and characteristics of OMAs, yielding a greater understanding of their behavior in both industrial and environmental flows.