Petrochemistry and Chemical Engineering

Biography

Biography: Qiang Chen

Abstract

The fine mineral solids in Alberta oil sands are associated with a significant amount of organic matter. These organically-modified solids hinder bitumen aeration and stabilize water-in-oil emulsions, leading to low bitumen recovery and poor bitumen quality. The study of these organic coating on the fine solids has been elusive due to the nanometer length scale and the unsuitability of sampling in high vacuum sample chambers. In the present work, we report the first application of PeakForce Quantitative Nanomechanical Mapping (QNM) Atomic Force Microscopy (AFM) to study the organic coating on the fine solids extracted from bitumen froth. Taking advantage of the simultaneous nano-scale resolution topographic imaging and adhesion mapping enabled by the PeakForce QNM-AFM, the mineral and organic components in the fine solids were distinguished due to their variations in shapes and mechanical properties. The organic coating on the clay minerals was clearly visualized on the adhesion maps, showing a patchy-distributed structure. The area percentage of the surface organic coverage on clay basal faces was calculated to be 17±6%, and the average thickness of the organic coating was estimated to be 1.4 nm based on the adhesion maps. The organic matter coated on bitumen froth fine solids, which cannot be washed off by toluene, was softer than the asphaltene fraction of oil sands bitumen.

The fine mineral solids in Alberta oil sands are associated with a significant amount of organic matter. These organically-modified solids hinder bitumen aeration and stabilize water-in-oil emulsions, leading to low bitumen recovery and poor bitumen quality. The study of these organic coating on the fine solids has been elusive due to the nanometer length scale and the unsuitability of sampling in high vacuum sample chambers. In the present work, we report the first application of PeakForce Quantitative Nanomechanical Mapping (QNM) Atomic Force Microscopy (AFM) to study the organic coating on the fine solids extracted from bitumen froth. Taking advantage of the simultaneous nano-scale resolution topographic imaging and adhesion mapping enabled by the PeakForce QNM-AFM, the mineral and organic components in the fine solids were distinguished due to their variations in shapes and mechanical properties. The organic coating on the clay minerals was clearly visualized on the adhesion maps, showing a patchy-distributed structure. The area percentage of the surface organic coverage on clay basal faces was calculated to be 17±6%, and the average thickness of the organic coating was estimated to be 1.4 nm based on the adhesion maps. The organic matter coated on bitumen froth fine solids, which cannot be washed off by toluene, was softer than the asphaltene fraction of oil sands bitumen.