posted on 2021-03-29, 07:04authored byAnita, Wasif Zaheer, Lacey Douglas, Diane G. Sellers, Subodh Gupta, Sarbajit Banerjee
As a result of the depletion of conventional
oil reserves and the
unprecedented growth in world energy demand, increasing attention
has focused on the extraction and utilization of unconventional oils.
The high viscosity of these unconventional hydrocarbons, specifically
bitumen and heavy crude oil, is an obstacle to their transportation
through conventional means such as pipelines. Rheological challenges
associated with the transportation of bitumen are typically addressed
through dilution with light hydrocarbons and thermal jacketing, which
consume considerable energy and result in wasteful consumption of
pipeline capacity with diluent fluids. Liquid-phase transportation
further poses the risk of spillage and ecological contamination. Enabling
the transport of bitumen as a solid-phase material will mitigate the
transportation constraints of pipelines and the disastrous effects
of oil spills. The formation of bitumen prills that can be reversibly
fluidized at the point of recovery presents a considerable challenge.
To prepare solid-phase bitumen, we have sought to encapsulate lighter
fractions of bitumen within a cross-linked shell of asphaltenes recovered
from the same source. Asphaltenes are extracted from bitumen and reconfigured
to coat the outer surfaces of bitumen droplets, thereby constituting
core–shell microcapsules. An automated jetting system equipped
with a dual-flow nozzle has been reconfigured to prepare bitumen microcapsules
coated with cross-linked asphaltenes. The core–shell microcapsules
are collected in a heated surfactant-water bath designed to prevent
capsule agglomeration and enhance the cross-linking of the asphaltenes
shell. The release of bitumen in response to the application of mechanical
stress has been studied and indicates that the microcapsules exhibit
size-dependent stress-withstanding abilities ranging up to ca. 145
kN/m2 for 2.4 mm microcapsules. The prepared microcapsules
demonstrate the viability of solid-phase transportation of bitumen
via roadways and marine tankers through reconstitution of the components
of bitumen without the need for extraneous additives.