Browsing by Author "Perdicakis, Basil"

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    Mineralogical characterization and thermodynamic modelling of scales formed in once through steam generators
    (Elsevier, 2022-01-15) Klyukin, Yury I.; Nightingale, Michael; Perdicakis, Basil; Mayer, Bernhard; Tutolo, Benjamin
    Extraction of hydrocarbons from oil sand deposits relies on technologies designed to lower bitumen viscosity, either by thermal energy or combination of thermal energy and solvents. Thermal energy is commonly delivered by steam. Once-through steam generators (OTSGs) are the most common class of generators used to generate steam from boiler feed water (BFW) at high pressure and temperature. Generated steam is used to mobilize the bitumen in the in situ reservoirs, and then water-bitumen emulsion is produced and processed, separating a hydrocarbon product and oil-free water, which subsequently will be reused to generate steam after treatment. Some of the aqueous constituents remaining or added during steam interaction with oil sands and subsequent treatment contribute to scale growth in OTSG tubing. Accumulation of the scale in OTSGs may lead to tubing failure due to overheating. In the present work we focused on inorganic scales – solid phases formed by components dissolved in BFW. We used a suite of geochemical, mineralogical and modelling techniques to characterize and model the inorganic components of scale samples provided by Canada's Oil Sands Innovation Alliance (COSIA) from OTSGs operators at multiple sites in Northeastern Alberta, Canada. We identified the composition of minerals in the scales as Na-, Ca-, and Mg-silicates with relatively low SiO44- content (inosilicates). Our modelling results allowed us to constrain the evolution of pressure, temperature, pH, mineral phases, and dissolved components in BFW as it undergoes heating in the OTSG to form steam and boiler-blowdown water. Modelling results are consistent with observed minerals and are promising for future management of scale formation processes.
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    ItemOpen Access
    Mineralogical characterization and thermodynamic modelling of scales formed in once through steam generators
    (Elsevier, 2021-09) Klyukin, Yury I.; Nightingale, Michael; Perdicakis, Basil; Mayer, Bernhard; Tutolo, Benjamin
    Extraction of hydrocarbons from oil sand deposits relies on technologies designed to lower bitumen viscosity, either by thermal energy or combination of thermal energy and solvents. Thermal energy is commonly delivered by steam. Once-through steam generators (OTSGs) are the most common class of generators used to generate steam from boiler feed water (BFW) at high pressure and temperature. Generated steam is used to mobilize the bitumen in the in situ reservoirs, and then water-bitumen emulsion is produced and processed, separating a hydrocarbon product and oil-free water, which subsequently will be reused to generate steam after treatment. Some of the aqueous constituents remaining or added during steam interaction with oil sands and subsequent treatment contribute to scale growth in OTSG tubing. Accumulation of the scale in OTSGs may lead to tubing failure due to overheating. In the present work we focused on inorganic scales – solid phases formed by components dissolved in BFW. We used a suite of geochemical, mineralogical and modelling techniques to characterize and model the inorganic components of scale samples provided by Canada's Oil Sands Innovation Alliance (COSIA) from OTSGs operators at multiple sites in Northeastern Alberta, Canada. We identified the composition of minerals in the scales as Na-, Ca-, and Mg-silicates with relatively low SiO44- content (inosilicates). Our modelling results allowed us to constrain the evolution of pressure, temperature, pH, mineral phases, and dissolved components in BFW as it undergoes heating in the OTSG to form steam and boiler-blowdown water. Modelling results are consistent with observed minerals and are promising for future management of scale formation processes.
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    ItemOpen Access
    Modelling the Impact of Tube Fouling on Heat Transfer in Once-Through Steam Generators
    (2019-04-30) Herman, Steven; Mehrotra, Anil K.; Benneker, Anne M.; Gates, Ian Donald; Perdicakis, Basil
    In Alberta’s oil sands, once-through steam generators (OTSGs) produce steam for in-situ recovery of bitumen. The industry’s water quality, high recycle, and operating conditions encourage OTSG fouling, with economic, safety, and environmental consequences. Relevant fouling mechanisms are not fully understood, complicating the study of heat transfer in OTSGs via radiation, convection, conduction, and boiling. To progress the study of OTSG fouling, a mathematical model was built in Microsoft Excel, using industry design data, to demonstrate fouling’s heat transfer impacts. This accessible model format is novel. The model demonstrates fouling acts as a thermal resistance to reduce heat transfer efficiency in OTSGs and can increase tube wall temperatures above safe operating limits, potentially causing tube failures. For conductivities between 0.05 – 2 W/m K and thicknesses between 0.1 – 30% of inner radius (0.4 – 11 mm), average tube wall temperatures above safe literature operating limits (i.e. 700 K) are predicted.