Rate of Bitumen Film Transfer from a Quartz Surface to an Air Bubble as Observed by Optical Microscopy
The rate of bitumen transfer from a bitumen-coated quartz plate to a gas bubble surface in aqueous alkaline solutions was recorded photographically. During bitumen spreading, a bulk layer followed the formation of thin bitumen films (precursor films). The bulk layer spread at the bubble surface with a velocity of about one order of magnitude less than the velocity of the precursor film. The energy of activation for spreading of the bulk layer varied from about 66 to 123 kJ/mol depending on the stage of bitumen spreading but remained constant at about 105 kJ/mol for the precursor film. Results are discussed with respect to fundamental issues associated with flo t a t i o n r e c o v e ry of heavy oils.
Physical and chemical aspects of “precursor films” spreading on water from natural bitumen
Abstract Interfacial chemistry and physics dominate fluid distribution within crude oil reservoirs and the efficiency of hydrocarbon recovery. For improvements to be made in extraction and production processes, it is essential that the complex boundaries between the different reservoir phases are better understood. The purpose of the present paper is to describe a multi-technique study of the spreading behavior and composition of so-called precursor films deriving from natural bitumen extracted from Athabasca oil sands at an air-water interface. Film spreading on deionized water and saline subphases was followed using ellipsometry and film pressure measurements. The films comprise surface-active bitumen components which could potentially influence the surface chemistry of the reservoir, with implications for mineral wettability, hydrocarbon recovery and the formation and stabilization of oil/water emulsions and oil foams during production. Infrared spectroscopy and mass spectrometry identified the presence of carbonyl groups as well as various classes of sulfur and oxygen hetero-species in the precursor films.
Separation of oily water by bubble column.
Experiments for removing emulsified oil from oily water by use of a bubble column were carried out in oil-in-water emulsion of dilute suspension and minute oil particles. The hydrodynamic performance of bubble layer in a column is evaluated approximately by the results obtained by authors. The removal rate of emulsified oil from oily water is influenced by many factors, and the fastest removal rate is obtained when pH is about 4. The mechanism of the removal of emulsified oil follows the first-order kinetics proposed by Imaizumi et al. under the assumption that the rate constant has a distribution expressed as the gamma distribution function.