Browsing by Author "Mehrotra, Anil Kumar"
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- ItemOpen AccessA Model for the prediction of the solubility of bitumen in hydrocarbon diluents(1987) James, Niel Edward; Mehrotra, Anil Kumar
- ItemOpen AccessA novel methane emission control technique for bioreactor landfills(2006) Perdikea, Konstantina; Mehrotra, Anil Kumar; Hettiaratchi, J. Patrick A.
- ItemOpen AccessA thermal study of wax deposition from paraffinic mixtures(2003) Bidmus, Hamid; Mehrotra, Anil Kumar
- ItemOpen AccessAn Efficient algorithm for optimal pipeline design and operation(1991) Bolkan, Yasemin G.; Mehrotra, Anil Kumar
- ItemOpen AccessAn experimental investigation of deposition from wax-solvent mixtures under turbulent flow with heat transfer(2007) Fong, Nelson; Mehrotra, Anil KumarA flow-loop apparatus, incorporating a co-current double-pipe heat exchanger, was developed for investigating the deposition of solids from multi-component solutions of a wax and a paraffinic solvent under turbulent flow. The deposition experiments were performed at Reynolds numbers from 10000 to 31000 with 7, 10 and 15 mass% waxsolvent mixtures at different hot and cold stream temperatures. In all experiments, the deposit was formed rapidly, with thermal steady-state attained within 20-30 min. The deposit mass decreased with an increase in the Reynolds number, the wax-solvent mixture temperature, and the coolant temperature. The data were analyzed with a steadystate heat-transfer model, which confirmed the deposit mass to depend on the relative magnitudes of the thermal resistances in series as well as the fractional temperature drop across the deposit-layer. The estimated liquid-deposit interface temperature was shown to be the wax appearance temperature (WAT) of each wax-solvent mixture within experimental error limits. The average thermal conductivity of the deposits was estimated to be 0.35 W m-1 K-1• The GC analysis of deposit samples showed their wax content and carbon number distribution to vary with the deposition time and Reynolds number. Overall, the results of this study, together with results obtained previously under laminar flow, confirm that the deposition process from 'waxy' mixtures is primarily thermally-driven under both laminar and turbulent flow regimes.
- ItemOpen AccessAn investigation of mass transfer effects on aeration process for soil remediation(1994) Karan, Kunal; Mehrotra, Anil Kumar
- ItemOpen AccessAn Investigation of Solids Deposition from Two-Phase Wax–Solvent–Water Mixtures(2014-05-05) Kasumu, Adebola Sadiq; Mehrotra, Anil KumarThis study presents an investigation of the thermophysical behaviour and deposition tendency of “waxy” mixtures, with and without the addition of water as a liquid phase. In the first part, the wax precipitation temperature (WPT) of several compositions of a multi-component waxy mixture (comprising a multi-component paraffinic wax dissolved in a multi-component solvent) was measured at controlled cooling rates. Results indicated that the WPT of a waxy mixture is not a constant property, as it varied with the cooling rate. Experimental results were used to express the WPT as a function of the cooling rate and mixture composition. With the WPT being dependent on the cooling rate, it may not correspond to the thermodynamic liquidus temperature for the liquid-to-solid phase transformation process. The deposition of solids from single-phase and two-phase waxy mixtures (second phase being water) was studied using two different experimental apparatuses. A flow-loop apparatus was used to study the effects of water content, wax mixture and coolant temperatures, and flow rate, in two-phase waxy mixtures flowing under turbulent flow conditions. A cold finger apparatus was used to further investigate the effects of time and stirring rate on wax deposition in single-phase waxy mixtures, and the effect of water content in two-phase waxy mixtures. In both sets of experiments, the water content of the deposit was found to be not related to the water content of the waxy mixture. The deposit mass (on a water-free basis) decreased with an increase in Reynolds number, the mixture temperature, and/or the coolant temperature. The deposit mass both increased and decreased with the water content of the waxy mixture, depending on the deposition time. Results showed the solids deposition from waxy mixtures to be a fast process; for example, 56% of the deposition process in the cold-finger experiments was completed in 0.07% of the time to reach steady-state. The deposition data were analyzed with a steady-state heat-transfer model, which also indicated that the liquid–deposit interface temperature was close to the wax appearance temperature (WAT) of the waxy mixture. The predictions from a transient heat-transfer model, based on the moving boundary formulation, matched satisfactorily the effect of time on the deposition process in the cold-finger experiments. Overall, the results of this study confirm that the deposition process from waxy mixtures is a relatively very fast process, and is primarily thermally-driven.
- ItemOpen AccessAn investigation of the interactions between organic contaminants and various humic acids by DSC analysis(1998) Laplante, Michelle Lynn; Mehrotra, Anil Kumar
- ItemOpen AccessAnalysis of energy utilization by an urban center: application to the city of Calgary(2009) Jayasinghe, Poornima; Mehrotra, Anil Kumar
- ItemOpen AccessAnalysis of Flow and Heat Transfer in OTSGs and Injection Wells(2023-04-21) Sivagnanam, Mohan; Gates, Ian Donald; Mehrotra, Anil Kumar; Hejazi, Hossein; Ponnurangam, Sathish; Mwesigye, Aggrey; Sanders, Sean R.Steam for enhanced oil recovery, generated by using once-through steam generators (OTSGs), is injected into extra heavy oil (bitumen) bearing formations to raise the temperature of the oil within. At elevated temperatures, the oil mobility is raised enabling it to be produced to surface. To improve the performance of steam-based processes, the research documented here focuses on two components of the process. The first component is steam generation in OTSGs and the second is injection of steam into the reservoir. More specifically, in the first component, the impact of foulant is examined and how a deliberate flow perturbation can be used to delay the onset of foulant. In the second component, steam flows through slotted liners and flow control devices are investigated. The results show that the thicker the foulant, the higher the outer tube wall temperature and the lower is the water temperature – the foulant acts as an insulator on the inner wall of the tube. Flow perturbations are demonstrated to yield benefits for lowering the outer tube wall temperature. An examination of thermocouples used to measure the temperature of the tube surface in OTSGs is also presented. Simulation results for a thermocouple welded on an OTSG tube showed a discrepancy between the actual temperature and the thermocouple measurement. The use of a radiation shield is shown to provide a better estimate of the bare tube temperature. The analysis of a slotted liner shows that the slot area plays a crucial role in flow distribution within the well and reservoir. Supersonic flow in flow control devices is strongly dependent on steam quality and some of the systems examined exhibited a condensation shock and shock diamonds with exit velocity greater than the inlet. A longer diffuser is shown to minimize the impact of shock waves on the exit velocity.
- ItemOpen AccessAsphaltene Precipitation from Bitumen/Multicomponent Solvent Mixtures(2021-03-01) Rivero Sanchez, Javier Alberto; Yarranton, Harvey W.; Ponnurangam, Sathish; Mehrotra, Anil KumarBitumen is sometimes diluted with multicomponent solvents in oilfield processes and it is useful to predict if and how much asphaltenes may precipitate from these mixtures. The Modified Regular Solution (MRS) approach was adapted for these applications. For this purpose, the onset and yield of asphaltene precipitation from heavy oil diluted with multicomponent solvents were determined at temperatures from 21 to 180°C and pressures up to 10 MPa. The solvents considered include: 1) mixtures of n-pentane, n-heptane, cyclohexane, and toluene; 2) petroleum solvents such as condensates, diesel, and kerosene. The asphaltene yields at ambient conditions and high pressures were measured gravimetrically in a bench top apparatus and in a blind cell apparatus, respectively. The onset of asphaltene precipitation was extrapolated from asphaltene yield data at ambient conditions and determined optically at higher pressures with titrations performed in a high-pressure microscope. Temperature dependent binary interaction parameters (BIP) were introduced to a previously developed MRS approach to model asphaltene precipitation from heavy oil diluted with blended pure solvents. BIP for the cyclohexane/asphaltene and toluene/asphaltene pseudo-component pairs were sufficient to match all of the data collected with binary solvent blends. All other BIP were set to zero. The model with the BIP obtained from the binary solvent blends predicted the asphaltene onsets and yields from heavy oil with ternary solvent blends, generally to within the error of the measurements. A methodology to characterize petroleum solvents based on their GC assays to predict their molecular weight, density, and solubility parameters was developed. The methodology was tested against their measured densities at standard conditions and the solubility parameters determined by fitting the MRS model to yield data collected for bitumen diluted with these solvents. The asphaltene yields modeled using the proposed correlations as input to the MRS model matched the experimental data for all but one of the petroleum solvents and their blends with n-heptane with an overall average absolute deviation and bias of 1.1 wt% and -0.8 wt%, respectively. The MRS model did not match the asphaltene yield from the naphtha.
- ItemOpen AccessControlling methane emissions from heavy oil wells: Gas clustering simulation and optimization modeling(1999) Yang, Min; Mehrotra, Anil Kumar
- ItemOpen AccessDeposition and aging of waxy solids from paraffinic mixtures(2004) Parthasarathi, Prashanth; Mehrotra, Anil Kumar
- ItemOpen AccessDetermining the Onset of Asphaltene Flocculation in Solvent-Diluted Bitumen Systems(2016-01-18) SATTARI, MARYAM; Abedi, Jalal; Mehrotra, Anil Kumar; Maini, Brij; Hassanzadeh, Hassan; Lines, Laurence; Torabi, FarshidThe past several decades have seen conventional oil resources reaching plateau which triggered a shift in oil exploration towards heavier crudes such as heavy oil and bitumen. Light hydrocarbons, mainly consisting of light paraffins, are widely used as diluents in the production and upgrading of heavy crudes. The addition of a diluent to heavy oil or bitumen alters the chemical forces within the mixture initiating the aggregation of asphaltene particles. Temperature and pressure may also vary during reservoir depletion operations. A crucial and challenging side effect of such thermodynamic changes is solid deposition, which can significantly diminish production, damage the reservoir, or even necessitate early reservoir abandonment. Solid deposition in reservoirs, production wells, and top-side facilities is mainly composed of asphaltenic materials, sand, clay, and corroded metals. Asphaltene is the deposition material of interest in this study. In order to avoid asphaltene precipitation or develop a remedial action plan for the associated problems, it is essential to understand the fundamental variables driving asphaltene precipitation in oil. The first step is to determine the conditions under which asphaltene dispersed in crude oil flocculates out to form an asphaltene-rich solid phase. The current study was designed to locate the onset of asphaltene flocculation with respect to changes in the thermodynamic conditions. Extensive experimental work and mathematical modelling were conducted to predict the incompatibility region of solvent-diluted bitumens. The precipitants in this study, n-pentane, n-hexane, and n-heptane, were chosen from the most common hydrocarbon cuts used in solvent-assisted heavy oil recovery methods in Alberta. Two Alberta bitumens were considered in this study. The effects of temperature, pressure, and composition on the onset of flocculation were investigated for various systems of solvent-diluted bitumens. Experimental values for the viscosity and density of the n-alkane-bitumen mixtures produced a pattern from which the onset of asphaltene flocculation could be accurately determined. In the modelling section, a CPA-EOS model was successfully tuned to predict asphaltene precipitation from solvent-diluted bitumens.
- ItemOpen AccessDevelopment of Quantification Methodology for Methane Emission through Venting in Alberta(2018) Tan, Shin Roey; Mehrotra, Anil KumarMethane emission accounts for a huge proportion of the total GHG as it is 25 times more potent than CO2. New requirements through Directive 60 from AER mandate producers to quantify and report on the methane emissions from the facilities. This research fo
- ItemOpen AccessEffects of shear rate and time on deposition from wax-solvent mixtures under turbulent flow(2008) Tiwary, Ravindra; Mehrotra, Anil Kumar
- ItemOpen AccessEffects of temperature and pressure on asphaltene particle size distributions in bitumen-diluent(1993) Nielsen, Bent Bjarno; Mehrotra, Anil KumarIn order to investigate the effects of temperature and pressure on the size of asphaltene particles, a novel series of pressure and temperature cells were constructed and integrated with a Brinkmann Particle Size Analyzer. Four separate oils, from an asphaltic condensate to a heavy crude oil were examined using n-pentane and nheptane as diluents. Atmospheric pressure investigations with n-heptane as the diluent over the temperature range of 0°C to 50°C showed no change in particle size, but did reveal bimodal distributions. The effect of temperature from 0°C to 100°C and pressure from 2.2 MPa to 5. 6 MPa were successfully explored. Increasing the pressure induced a small change in the mean size of the particles, except for the Lindberg oil particles for which the mean size decreased slightly. A variation of the temperature from 0°C to 100°C showed little effect on asphaltene particle size, except upon the Border condensate. The heavier molecular weight oils from Cold Lake and Lindberg, Alberta formed 11 super agglomerates II or macro-agglomerates at 75 ° C and higher. The Border condensate and Countess oil both displayed instances when a bimodal size distribution was apparent. Most of the runs showed some suggestion of another distribution in addition to the main particle size distribution.
- ItemOpen AccessExperimental measurement of gas diffusivity in bitumen: Results for co2, ch4, c2h6, and n2(2000) Upreti, Simant Ranjan; Mehrotra, Anil Kumar
- ItemEmbargoGas-free and gas-saturated bitumen viscosity prediction using the extended principle of corresponding states(1985) Johnson, Susan Elizabeth, 1961-; Mehrotra, Anil Kumar
- ItemOpen AccessHydrothermal conversion of biomass to bio-oil(2011) Yin, Sudong; Mehrotra, Anil Kumar
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