Recovery, characterization and conceptual modelling of Non‐Bituminous organic materials from oil sands

Abstract

The hot water process has recovered approximately 90% of the bitumen in oil sands, but the remaining 10% of bitumen and naphtha has been lost to the tailings pond. Recovery of bitumen and non-bituminous combustibles (NBC) from centrifuge, scroll and final tailings has been considered. he "hot water" extraction process has been the preferred T commercial method for isolating bitumen from oil sands. This process recovers approximately 90% of the bitumen in the feed (Camp, 1974). Without extra processing steps, the remaining 10% of the bitumen along with a small fraction of diluent naphtha is lost to the tailings pond, representing a significant energy loss. For example, for a plant producing 2 1,000 m3/d (1 30,000 bbl/d) of synthetic crude valued at, for example, $14/bbl, approximately U.S. $60 million/year worth of bitumen is lost to tailings.To recover additional bitumen and diluent naphtha from the aqueous tailings, techniques such as flotation-scavenging, aeration, flocculation, and sorption have been studied by several researchers. The success of the separation process in a flotation system depends heavily on the proper control of surfaces and interfaces involved in the highly complex mixture of several solid phases forming an aqueous suspension through which air bubbles are dispersed. Davitt (1 975), and Bain and Roberts (1979) have described methods for reprocessing tailings sludge by agitation, aeration, and dilution combined with flotation and skimming, respectively. The tailings sludge has been aerated and agitated to form a bituminous froth layer and a lower layer of mineral and water. Sodium silicate has been added as a process aid to improve bitumen recovery. Hall and Tollefson (1979,

Effect of clays and calcium ions on bitumen extraction from athabasca oil sands using flotation

“…L'ajout d'argiles d'illite ou de kaolinite ne modifie que marginalement la concentration d'ions de calcium dans la suspension. Une plus forte adsorption des ions A few conceptual models incorporating calcium ions and various related components were proposed to explain some observations in bitumen extraction (Bowman, 1967;Takamura and Chow, 1983;Takamura and Wallace, 1988;Sengupta and Tollefson, 1997;Zhou et al, 1999). Bowman (1 967) and Takamura and Chow (1 983) adopted the electrical double-layer theory to explain the observed bitumen depression by considering the effect of calcium ions on bitumen-sands interactions.…”

The Influence of Tailings Composition on Flocculation

“…The organic matter, consisting of hydrophobic and bi‐wettable solids, was linked to MFT stability . Sengupta et al observed that tailings contained water soluble organic material with chemical structures similar to humic and fulvic acids (Figure ), and proposed a model for the roles of Ca 2+ and Fe 3+ ions in the complexation of carboxylic acid groups of the organic compounds to clay surfaces (Figure ) …”

“…A model for the interactions between bitumen, minerals, and non‐bituminous combustibles (NBC) in tailings proposed by Sengupta …”

“…[13] soluble organic material with chemical structures similar to humic and fulvic acids ( Figure 4), and proposed a model for the roles of Ca 2þ and Fe 3þ ions in the complexation of carboxylic acid groups of the organic compounds to clay surfaces ( Figure 5). [30] Electrophoretic techniques moved the focus back to the mineral model of MFT stability, as the electrophoretic mobility of pure clays was found to be influenced to a greater extent by the bicarbonate ion concentration than by the presence of organic matter. [11,31] Electrostatic forces may be used to explain the stability of fine particles in suspension, as described by the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability.…”

“…A model for the interactions between bitumen, minerals, and non-bituminous combustibles (NBC) in tailings proposed by Sengupta. [30] particles (2-44 mm), and fine clay particles (< 2 mm). [35] Mikula et al described the fine particle fraction of MFT specifically as particles with sizes < 22 mm, indicating that these only comprise a certain portion of the whole tailings.…”