Recovery of Cyclohexane from Oil Sands Gangue Using  Microwave: Influence of Fine Particles
Creators: Hussein, Tasneem
Publisher: name: University of Alberta Library
Year: 2022

<p>The extraction of bitumen from oil sands using non-aqueous extraction (NAE) techniques has the <br>
potential to replace currently used water-based extraction techniques. High bitumen recovery rates, lower <br>
freshwater requirements, and elimination of afterward tailing ponds are all advantages of non-aqueous <br>
extraction. Other benefits include a significant reduction in energy use and greenhouse gas emissions <br>
related to global warming and ozone depletion.<br>
Using an organic solvent, bitumen is extracted from the oil sands ore during the nonaqueous extraction <br>
process, leaving behind a mixture of coarse and fine solids containing water, residual bitumen, and <br>
residual solvent (cyclohexane in this study), or “gangue”. Regardless of its numerous advantages, a <br>
significant environmental and economical drawback of the NAE method is the removal of solvent from <br>
the gangue post extraction.<br>
A well-defined procedure to control the gangue composition was necessary in order to accurately analyze <br>
the impact of gangue components on solvent recovery from the gangue. Reconstituted gangue samples <br>
were prepared to create a synthetic sample whose drying behavior represented that of the non-aqueous <br>
extraction gangue. The utilization of reconstituted gangue was necessary because it represented samples <br>
whose composition could be precisely controlled for analysis. <br>
This research demonstrated the effect of varying the content of fine particles at constant residual bitumen, <br>
water, and cyclohexane contents on the removal of cyclohexane from reconstituted gangue using two <br>
different solvent removal mechanisms: microwave-only in and air-drying followed by microwave. Heat <br>
was generated internally within the reconstituted gangue during the microwave experiment upon the <br>
interaction of the dipolar molecules with microwave radiation.<br>
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For reconstituted gangue samples undergoing only microwave heating, cyclohexane required more time <br>
to go through phase change, regardless of fine particles content. The temperature at which cyclohexane <br>
underwent phase change was significantly depressed for all samples undergoing microwave heating for <br>
all contents of fine particles. There was no apparent difference between the duration of cyclohexane <br>
evaporation in samples with 10% and 20% fine particles. The time required for cyclohexane to be <br>
removed from the gangue becomes independent of fine particles content at increased contents of fine <br>
particles. The maximum temperature reached by the Soxhlet solids remained unchanged for gangue <br>
samples with 10 wt.% fine particles but somewhat increased upon the addition of 20 wt.% fine particles, <br>
relative to samples containing 0 wt.% fine particles.<br>
For reconstituted gangue samples undergoing air-drying prior to microwave heating, the duration at <br>
which cyclohexane underwent phase change reached its maximum at 10 wt.% fine particles content. This <br>
duration was similar for samples containing 0 wt.% and 20 wt.% fine particles. The temperature at which <br>
cyclohexane underwent phase change was comparable to cyclohexane’s normal boiling point for all <br>
contents of fine particles. The duration of cyclohexane evaporation in reconstituted gangue samples <br>
containing 10% and 20% fine particles was doubled and tripled, respectively, relative to reconstituted <br>
gangue samples containing no fine particles. The time required for cyclohexane to evaporate from the <br>
reconstituted gangue significantly increases at increased contents of fine particles. The average <br>
maximum temperature reached by the Soxhlet solids was independent of the content of fine particles. <br>
Finally, fine particles accelerated the recovery of cyclohexane using microwave and lowered the <br>
evaporation onset temperature.</p>