One of the challenges of non-aqueous (waterless) extraction processes in the oil sands is the presence of tiny silica or clay particles after solvents are used to extract the bitumen. Trapped in the bitumen, these particles can accumulate in process equipment, causing trouble at the refinery. University of Alberta researcher Hongbo Zeng is working on a Future Energy Systems (FES) project that could solve this problem.
Since 2017, Zeng and his team have been studying the particles at a molecular level and nanoscale for clues that could help in their removal.
“If we can understand the properties and interaction mechanisms behind these stable particles, we can develop sustainable ways to separate them and make bitumen cleaner,” says Zeng, who holds the Canada Research Chair in Intermolecular Forces and Interfacial Science.
The team is using an atomic force microscope and other specialized equipment to probe the particles’ surface properties and how they interact with other molecules. The research indicates that certain materials, called polymers, could provide a solution. Certain functional polymers naturally bond with the particles, helping these contaminants cluster for easier removal.
“Polymers have long molecular chains. Each polymer can grab many particles, enhancing aggregation and removal,” Zeng explains.
Currently Zeng and his team are running tests in the laboratory to better understand what causes the particles to clump together. Then, they’ll move on to the task of creating suitable polymers with improved performances. So far, the team has identified a number of synthetic and natural polymer materials that could be used.
“If we can better understand the fundamental science, we’re going to save a lot of time and effort in our research,” he says.
This work, Zeng says, has the potential to improve bitumen quality and lower equipment and energy costs by reducing upsets in refinery operations. In addition, the knowledge they gain about polymers could be applied to improve other parts of the oil sands, including tailings ponds.
“If we can develop more efficient and more responsible ways to exploit our oil resource, that’s a very positive outcome,” Zeng says.