THE ROLE OF TEXAS CRUDE OIL IN MINERAL FLOCCULATION EVOLUTION: A LABORATORY INVESTIGATION
Date
2020-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
As oil spills are now more common in coastal regions, understanding natural
cohesive sediment interactions with spilled oil is also becoming increasingly important
because the presence of oil can signi cantly alter the properties of mineral
occula-
tion in a marine environment. Moreover, the presence of minerals and their ability
to attach to or enclose oil droplets can also a ect the fate of oil. One property of
signi cance that requires further investigation is the evolution of
occulation over a
time period because it can be used to quantify the stickiness of certain types of
oc.
To fully investigate the role oil plays in this process, it is also necessary to understand
the interplay between sediment type and concentration, mixing time, and seawater
turbulence level with regards to controlling the
occulation rate, and the importance
each of these factors holds on the overall
occulation process. Preliminary laboratory
observation has suggested that the most e cient method to test this interplay is to
rst observe the signi cance that di erent types of sediment, as well as di erent con-
centrations of crude oil hold while controlling the turbulence energy and
occulation
time. The laboratory results presented in this thesis attempt to quantify the e ects
that sediment type and sediment/oil concentrations each have on the
occulation evo-
lution rate. Mineral and oil-mineral
ocs have been generated using a magnetic stirrer
operated at a set number of revolutions per minute and a custom designed jar. To
properly create detailed data sets of
oc properties both with and without oil, it was
necessary to hold the time period and turbulence level constant. A Vectrino II acoustic
pro ling velocimeter was also deployed to measure turbulence level in the jar. Various
laboratory experiments, in addition to substantial literature review, were also carried
out to determine proper sediment and oil concentrations. During testing,
oc samples
were extracted from the jar and analyzed under a digital camera microscope using a
x
pipette at set time intervals over the course of the two-hour time period. By observing
oc through this method, a time series was generated for each experiment in order
to quantify the
occulation evolution rate with respect to the various aforementioned
parameters. Preliminary ndings have veri ed past work in showing that Bentonite is
signi cantly more cohesive than Kaolinite, and deeper analysis also shows that Ben-
tonite is a more e cient clay for entrapping oil droplets. Results also show that the
addition of oil makes
ocs signi cantly less sticky regardless of clay type, and it in-
creases the time required for a
oc population to reach an equilibrium state. Future
experiments and analysis are necessary to quantify more complex interactions, such
as variable turbulence energy,
occulation time, the use of diverse concentrations and
types of sediment, oil, organic material, and non-cohesive sediment (sand) that are
often present in a marine environment.
Description
Keywords
civil engineering, crude oil, mineral flocculation