Asphaltene properties vary with separation method and sometimes with individual technique. Factors such as contact time, solvent-to-crude oil ratio, and temperature influence asphaltene precipitation and are somewhat standardized. However, the final step in most separations, washing the asphaltene filter cake with solvent, is not standardized. Asphaltene properties can be very sensitive to small amounts of resins and therefore may be sensitive to the amount of washing. Asphaltenes were extracted with three different levels of washing from four source oils (Athabasca, Cold Lake, Lloydminster, and Peace River). In all cases, increased washing decreased asphaltene yield and slightly increased asphaltene density. Increased washing significantly increased molar mass and decreased the solubility of the extracted asphaltenes. A new washing method using a Soxhlet apparatus removed the largest amount of resinous material and yielded asphaltenes with significantly different properties from conventionally washed asphaltenes. Since more resinous material was removed, the Soxhlet method allows a more direct comparison between asphaltenes from different sources. Asphaltenes were also extracted using three standard separation methods, IP 143, ASTM D4124, and a method proposed by Speight. Some property variations between the methods were observed and a set of criteria to obtain consistent samples is proposed.
This paper reviews methods for the prediction and correlation of Newtonian viscosity for pure components and mixtures of dilute gases, dense gases and liquids, focussing on those which are suited for practical engineering use. The methods reviewed were chosen because they are well known and accepted or appear potentially promising. They are categorized as theoretical, semi‐theoretical or empirical and further distinguished as predictive or correlative. Brief derivations with relevant equations and discussions on limitations and reliability of results are presented. In addition, the applicability and average deviations for each method are tabulated, with the recommended methods clearly stated. Furthermore, some gaps in viscosity prediction/correlation are identified and promising approaches are discussed.
New data on density andgas-solubilityforathab asca bitumen are Presentedfor C02, CH, and N2. The apparatus of Jacobs for saturating bitumen with a gas provided reliable viscosity measurements. This apparatus was modified to permit the isolation and removal of gas-saturated bitumen samples for solubility measurements. The solubility measurements were W.Y. Svrcek W.Y. Svrcek received his B.Sc. and Ph.D. degrees in chemical engineering from the University of Alberta, Ed-monton. He worked as a senior sys-tems engineer with the Control Sys-tems Group of the Technical Service De ment o Monsanto ompany, St. ouis, and as an Associate Pro-fessor at the University of Western Ontario, London, Ontario, and he is currently a Professor in the Department of Chemical and Petroleum Engineering at the University of Calgary, Calgary, Alberta. A.K. Mehrotra A.K. Mehrotra received his Ph.D. degree in chemical engineering from the University of Calgary. He holds an undergraduate degree from BITS, Pi-lani, India and a Master's degree from the Asian Institute of Technology, Thailand. Following his appointment as a research engineer; he is currently an Assistant Professor in the Department of Chemical and Petroleum Engineering at the University of Calgary. His research interests in-clude properties of gas-saturated bitumens, chlorination of coal ash for metals recovery and membrane processes for the treatment of oil sands waste water. Keywords: Oil sands, Gas solubility, Viscosity, Density, Bitumen, Athabasca bitumen, Carbon dioxide, Methane, Nitrogen. performed on a controlled depressurization set-up. The range of temperaturesfor these data is 250C to IOO'C; thepressure was varied up to 10 MPa. It was observed that C02 has high solubility in bitumen and causes tremendous reductions in _ viscosity. The solubility of nitrogen is quite low, whereas that of methane is intermediate. Introduction A knowledge of the physical properties of the oil present in Alberta tar-sands is required to mathematically model and simulate the processes used for the recovery of tar-sands. The data on gas-solubility, viscosity, and density for gas-saturated bitumen are of special importance to the in-situ techniques, s@c@ as C02-itijection and fire-flooding, that are now being ac-tiveiy pursued.Viscosity data for Athabasca bitumen (the dead oil) and the bitumen saturated with carbon dioxide (live oil) were presented by Jacobs(l). E)ata from similar experiments using methane and nitrogen gases were published subsequently by Jacobs and co-workers(2). The need existed, however, for the solubility data for these gases. Also needed were methods for correlating temperature and pressure with the viscosity and gas-solubility of bitumen. Experimental data for C02, CH4 and N2 gases are presented in this paper. A successful first attempt at cor-relating these data is presented elsewhere(3).The viscosity of gas-saturated oils (live oils) depends on the type of gas, bitumen composition, temperature and pressure. The qualitative relationship among the individual variables fo...
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