Formation and Transport of Large Oil-Mineral Aggregates
Restricted (Penn State Only)
- Author:
- Crognale, Michael
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 14, 2024
- Committee Members:
- Margaret Louise Byron, Thesis Advisor/Co-Advisor
Samuel Grauer, Committee Member
Robert Kunz, Professor in Charge/Director of Graduate Studies - Keywords:
- oil-mineral aggregate
particle-laden flow
aggregation - Abstract:
- 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. Various trends are observed in size distribution, but there does not appear to be any overarching governing factor that describes the size distributions for all initial concentrations. Formation of very large aggregates is most prevalent when the initial oil-sediment ratio (OSR) is less than or close to 1, and median large aggregate size generally increases as OSR decreases. The settling velocities of most large (> 300 µm) aggregates range from 5-15 mm/s, and settling velocity is mostly independent of size, shape, and initial concentration; it rather depends largely on aggregate density (i.e., oil content). Using settling velocity to find the approximate density of individual aggregates, we also observe partitioning, the tendency of sunken oil to preferentially consolidate into large, oily aggregates. All measured aggregates exceeding 1 mm in size comprise more than 80% oil, and larger initial oil concentrations yield aggregates with oil contents tending towards 90%. The largest aggregates by equivalent diameter also tend to be the oiliest. By describing the characteristics that OMAs exhibit from 25 combinations of initial oil/sediment concentrations, we gain further insight into the factors that govern their formation, behavior, and transport.