Andy Hong, PhD, University of Utah
This report summarizes findings at the end of Project Period on August 31, 2012:
1. Influence of decompression speed investigated
Previously venting speed showed significant impact on separation of bitumen from sand surface and resulting froth quality. Different combinations of low and high venting speeds were studied. For 30 cycles of compression and decompressions , with 22 times of slow venting followed by 8 times of fast venting, bitumen release of most complete and with good froth quality (74% bitumen recovery and 34% organic content in the froth were obtained from Asphalt ridge oil sand)
2. Water quality investigated
Chemical composition of process water after contact with Uinta Basin oil sand was analyzed. It was found to contain large amount of bromide, likely resulting from high concentration of bromide in the oil sand deposits. Organic compounds in the process water were also extracted and analyzed by GC/MS.
3. Dewatering characteristics of spent sands investigated
The dewatering ability spent oil sands was studied. The spent sands dewaters quickly. The Uinta Basin oil sand residual after being subjected to repeated pressure cycles contained about 16% of water and it lost 62% of the water content after 3 hours and lost 99% of moisture after 60 hours under normal venting conditions (at the load density of 0.6g/cm2 at room temperature).
4. Froth density investigated
Froth from oil sand HOSE after exposure to pressure cycles was measured for its density and found to be about 1.15g/ml. The froth could still float as the gas bubbles were attached onto the bitumen surface during compression and decompression cycles. The attached gas bubbles proved a hypothesis that that during decompression, large amounts of microbubbles were created that assisted in the dislodging of bitumen from the sand surface.
5. Dissolution and entrapment of carbon dioxide gas into the bitumen organics shown
Experimental results showed during compression dissolution and entrapment of CO2gas occurred in the bitumen that helped pry off the bitumen from surface when the oversaturated gas expanded from within during decompression – which was the enhanced release mechanism.