Browsing by Author "Nassar, Nashaat"
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- ItemOpen AccessA (w/o) microemulsion approach for in-situ preparation of high concentrations of colloidal metal oxide nanoparticles(2007) Nassar, Nashaat; Husein, MaenControl over nanopa1ticle size 1s a key factor which labels a given nanoparticle preparation technique successful. When organic reactions are mediated by ultradispersed catalysts the concentration of the colloidal nanocatalysts and their stability become key factors as well. Ultradispersed metal oxide nanoparticles have applications as heterogeneous catalysts for organic reactions, and were recently demonstrated as effective H2S(gl absorbents. The catalytic activity and absorption effectiveness of metal oxide nanoparticles depend primarily on their surface area, which in turn, is dictated by their size, colloidal concentration and stability. This work presents a water-in-oil (w/o) microemulsion approach for in-situ preparation of ultradispersed metal oxide/hydroxide nanoparticles, namely: iron and copper and discusses the effect of different (w/o) microemulsion variables on their stability and highest possible time-invariant colloidal concentration (nanoparticle uptake). The concentration of the stabilized metal oxides corresponded to the nanoparticle uptake. In-situ preparation of colloidal catalysts and absorbents minimizes aggregation associated with storage and transportation. Much higher surface area per unit mass of nanoparticles and per unit volume of the colloidal suspension than reported in the literature was obtained. The following trends in the colloidal concentration were common for the (w/o) microemulsion system and the heavy oil matrix. An optimum water to surfactant mole ratio, R, was found for which a maximum nanoparticle uptake was obtained. Nanoparticle uptake increased linearly with the surfactant concentration and displayed a power function with the precursor salt concentration. A mathematical model based on correlations for water uptake by Winsor type II microemulsions accurately accounted for the effect of the aforementioned variables on the nanoparticle uptake by the microemulsions. Furthermore, the in-situ microemulsion approach developed in the first part was applied for in-situ preparation of effective H2Scgl colloidal absorbents within heavy oil matrix. H2 Scgl is a by-product of insitu heavy oil upgrading with potential negative impact on underground water. In this work, preliminarily evaluations of the effectiveness of the in-situ prepared colloidal iron oxide/hydroxide in heavy oil matrix for the absorption of H2 S(gJ was conducted successfully.
- ItemOpen AccessCatalytic In-reservoir Upgrading: Effect of Porous Media and Deposition of Nanocatalyst(2017) Rodriguez, Victor Manuel; Pereira-Alamo, Pedro; Chen, Shengnan (Nancy); Nassar, Nashaat; Lines, Laurence R.; Semagina, Natalia V.Technologies merging enhanced oil recovery with In-situ upgrading can significantly increase the economic and environmentally efficiency of unconventional oil exploitation. The development of Nanocatalytic In-situ Upgrading via Dense Hot Fluid Injection is a promising approach that takes advantage of upgrading lowest value bitumen fractions while promoting additional recovery of oil in place. This research addresses some important aspects related to the development of this novel technology, focusing on the until now unattended relevance of thermal kinetics (absence of catalyst particles), the precise range of particles sizes produced using the nano-catalyst manufacturing unit prototype built by the research group and the interaction rock-nano-particles relevant for the targeted catalyst deposition. The main limitation facing in-situ thermal upgrading (in porous media) of Athabasca bitumen was found to be product stability. Vacuum residue conversions above 32% result in unstable products, and although high viscosity reductions and moderate improvement of other properties are obtained they are not sufficient to produce transportable products. Additionally coke precursors are significantly retained by the porous media that further limiting the process. The kinetic modeling of thermal upgrading in porous media demonstrated the catalytic behavior of the sand pack reflected in an increase of the apparent reaction order for the vacuum residue to a second-order-of reaction. The use of Nanoparticle Tracking Analysis (NTA) for size determination of nano-catalyst dispersed in bitumen or heavy oil fractions was successfully developed. The produced catalyst particle size was found to be 111 nm (mode) with 80% of the particles in the range 57-176 nm. The effect of the main operating variables over the nano-particle retention and deposition was studied. Over 95% of particles retention was obtained, with no observable effect on the sandpack’s oil permeability. Concentration profiles along the porous media are similar for all tested conditions, with around 30% of nanoparticles at the entrance. Correlations for the profile and cumulative concentration are proposed. The morphological study of the resulting deposition showed particles deposited as large agglomerates for low temperature deposition tests, while high temperatures produced individually deposited particles near the entrance of the porous media.
- ItemOpen AccessCharacterization and Kinetic Study of Ilmenite Ores for Methane Chemical-Looping Combustion(2018-01-12) Khakpoor, Nima; De la Hoz Siegler, Hector; Mahinpey, Nader; Ponnurangam, Sathish; Nassar, NashaatEmitted carbon dioxide from fossil fuels combustion is one of the most influential greenhouse gases leading to global warming. Chemical-looping combustion (CLC) is one of the most efficient methods for carbon capture, resulting in no energy penalty compared to alternative carbon capture methods. CLC is a nonconventional unmixed combustion process where the fuel and air reactions occur in separate reactors. CLC is, however, still a conceptual process due to a series of technical challenges, mainly related to the oxygen carrier. In particular, there is a need for a low-cost, highly stable oxygen carrier capable of withstanding multiple cycles without loss of its oxygen transport capacity and reactivity. Reactivity and oxygen-transport capacity of Canadian and commercial ilmenite ores in the chemical-looping combustion of methane were investigated in a thermogravimetric analyzer (TGA). Oxygen carrier performance was evaluated in multiple cycles during which Canadian ilmenite oxygen transport capacity increased from 2.7% to 14.2% and the commercial sample maintained an approximately constant oxygen transport capacity at 4.5%. XRD and SEM results indicate that new phases were formed, and surface morphology was transformed significantly during cyclic operation. The latter experimental finding explains the increased oxygen transport capacity of the Canadian ilmenite. Studies on carbon deposition on the ilmenite surface indicate that lower methane partial pressure and reduction temperatures are favorable to effectively prevent this phenomenon. The kinetic grain model (GM) was found satisfactorily to fit reduction rate data obtained at atmospheric pressure. Intrinsic reaction rates and kinetic parameters were assessed, accordingly. The activation energy values of 106.7 ± 10.6 kJ/mol and 95.0 ± 8.5 kJ/mol were estimated for the Canadian and commercial samples, respectively.
- ItemOpen AccessDepressurization Dynamic Modeling and Effect on Flare Flame Distortion(2016) Shafaghat, Ali; De Visscher, Alex Andre Hugo; Foley, Michael William; Nassar, NashaatThe aim of equipment depressurization in an upset operation is to maintain the internal pressure of the vessels and piping below the rupture pressure, as the material ultimate tensile strength decreases with temperature tolerance beyond the acceptable limit. Depressurizing also causes to decrease the extent and duration of leaks that may occur as a result of mechanical failure. In the case of ignition and fire, a depressurization system can limit the fuel supply to the fire. In addition, the main objective of the pressure relief facilities is to keep personnel safe as well as equipment exposed to overpressure conditions that happen during process upsets. This thesis is intended to examine the modeling of depressurization in different scenarios, evaluate flare flame distortion and heat radiation as the most important consequences of this event, and consequently offer some recommendations for the design of any gas plant that has potential for overpressure.
- ItemOpen AccessDetermining the Pore Structure of Activated Carbon from Petroleum Coke by Nitrogen Gas Adsorption(2017) Kaldenhoven, Richard; Hill, Josephine; Nassar, Nashaat; Marriott, Robert; Hill, JosephineWhen considering a material for use as a catalyst or adsorbent, its pore structure is important, and can be determined by nitrogen gas adsorption. This thesis focuses on activated carbon materials prepared from petroleum coke, which are challenging to characterize due to the difficulties in modelling their disordered pore structures. The published models used to calculate the pore structure from experimental data have been reviewed and compared. From this review a procedure has been developed to select the most appropriate model for the material being studied, which is generally based on 2-Dimensional Non-Local Density Functional Theory, and applied to four carbon materials with varying pore structures. The results from this procedure show that pore structure properties can be calculated from a single model, and have been complemented with carbon dioxide adsorption, hysteresis scanning isotherms, and helium ion microscopy images but further work is recommended with the latter two methods.
- ItemOpen AccessDevelopment of Nanostructured Catalysts for Efficient Syngas Production from Dry Reforming of Methane(2023-11-10) Zhou, Rufan; Mahinpey, Nader; Lu, Qingye; Hu, Jinguang; Ponnurangam, Sathish; Nassar, Nashaat; Xu, Chunbao (Charles)Converting greenhouse gases (CHGs) (carbon dioxide (CO2) and methane (CH4)) into valuable products is an essential way to eliminate the negative impacts of global warming. The catalytic dry reforming of methane (DRM) by CO2 offers a viable route for the efficient utilization of these two potent GHGs to produce syngas (CO and H2) as a valuable fuel and chemical feedstock. Nickel (Ni)-based catalysts have been widely used in DRM reactions because of their relatively high reactivity as transition metals and low production costs. However, these catalysts suffer from unideal reactivity at low operating temperatures, unideal thermal stability with Ni sintering and resulted in severe coke formation on the catalyst surface leading to rapid deactivation. Hence, the main objective of this study is to design and develop a stable and robust catalyst with improved DRM reactivity and low tendency for deactivation. In this doctoral study, the design of different catalysts with excellent activity and high stability for the DRM process will be studied. To achieve excellent catalytic activity and stability, different catalyst fabrication strategies with relatively facile synthesis approaches will be employed, such as the effect of active metal loadings, catalyst structures, distinguished support materials and the addition of promoters have been evaluated in this study. Meanwhile, several characterization techniques have been used to thoroughly understand the physicochemical and structural properties of the developed catalysts to develop a structure-property relationship. Moreover, the recent status of catalyst development is discussed and compared with that of the catalyst developed in our study. Process simulations based on the catalytic DRM process were also evaluated and analyzed in this study to further guide the development of the DRM process and help achieve its commercialization in the future.
- ItemOpen AccessDevelopment of Simplified Analytical methods for In-situ Detection of Ammonia and Urea in Aqueous Solutions(2021-06-09) Haq, Shamshad Ul; Hassanzadeh, Hassan; Nassar, Nashaat; Lu, Qingye (Gemma)In-field analysis of nitrogen-containing compounds such as ammonia and urea remains challenging due to the limitations of conventional methods such as non-portability, the toxicity of reactants, and the need for a trained operator. This study presents a colorimetric pH detection paper-based sensing as a promising technology which has the potential to replace conventional methods such as spectrophotometry and electrochemical methods for in-field screening of nitrogen-containing compounds. The application of filter paper and smart-handy devices (e.g., the smartphone camera and RGB app.) makes these sensing devices convenient, inexpensive, and suitable for instant field application. Moreover, the use of non-toxic reagents further stimulates the exclusivity of this technique. Besides, the pervaporation and headspace gas diffusion eliminate the interferences and sample pre-treatment requirement, which reduce the analysis time and cost.Cost-effective, highly sensitive, and convenient anthocyanin-based paper sensors for in-field determination of ammonia and urea were fabricated in this project. Sensors were fabricated by immobilization of anthocyanin extracted from natural sources such as red cabbage (Red-C), blueberry (Blue-B) and blackberry (Black-B) in deionized water (Aq100) and 80% ethanol-water mixture (Aq20Et80) by simple immersion. Ammonium ion and urea were converted to ammonia by alkalinization and thermo-catalytic urea hydrolysis, respectively. The generated ammonia is detected by the anthocyanin-based sensor. The sensor reaction zone imaged by a smartphone (or flatbed scanner) and processed for RGB quantification by ImageJ software to correlate the analyte concentration with red intensity absorbance. The anthocyanin-based ammonia sensor offered a dynamic linear working range (1-10 mg NH3-N/L) with 0.2911 mg NH3-N/L limit of detection (LOD). Similarly, the anthocyanin-based urea sensor presented a dynamic linear working range (5-30 mg urea-N/L) with 0.2911 mg urea-N/L limit of detection (LOD). The accuracy of the proposed paper-based sensors was validated by the standard spectrophotometry method, which makes the fabricated sensors suitable for in-field analysis.
- ItemOpen AccessEffect of Graft Density of Partially Hydrophobic Copolymers on the Treatment of Oil Sands Mature Fine Tailings(2021-12-07) Kalyanaraman, Gayathri; Trifkovic, Milana; Lu, Qingye Gemma; Achari, Gopal; Trifkovic, Milana; Nassar, NashaatAlberta is well renowned for its oil sands mining that has led to enormous deposits of waste called tailings (alkaline slurry of residual bitumen, clay, and water). The presence of clays and fine silts in the tailings successively reduce their ability to settle naturally and dewater under the effects of gravity. The continuous accumulation of the tailings and the inability to treat them pose a risk to its surroundings. To resolve these issues, industries utilize several techniques, among which flocculation methodology is commonly employed to enhance the dewatering performance, capture the suspended solids, and improve the strength of the tailings using polymers (flocculants). The flocculation effectiveness depends on the polymer design with respect to the tailings system it is acting on, and this comes from understanding the microstructure of the polymer-flocculated sediment. Traditionally there are two broad groups of polymers: hydrophilic (water-liking) and hydrophobic (water-hating) for MFT (Mature fine tailings) flocculation. Researchers have shifted the focus to partially hydrophobic flocculants due to the long-term consolidation issues with conventional hydrophilic flocculants. This study employs partially hydrophobic copolymers with three different graft densities (30%, 40%, 50%). A combination of mechanical (Rheology, Dean-stark) and imaging (Laser Scanning Confocal Microscopy (LSCM)) experiments were conducted to understand and correlate the microstructure of polymer with that of the resulting MFT aggregates. Rheological experiments were performed to assess the strength of the treated MFT sediment. The LSCM was employed to image the microstructure of the polymer dispersion and the flocculated MFT aggregates. The obtained MFT images were further quantified in volume fraction and fractal dimension to evaluate the amount of inter-floc water (present between the flocs). Similarly, Dean-Stark experiments were performed to evaluate the amount of intra-floc water (enclosed within the individual flocs). It was shown that as the graft density of the polymers increased, the “initial” flocculation performance considerably improved. In contrast, there was no significant change in the “long-term" rheological signature among the three samples. The information on the inter-floc and intra-floc water obtained from LSCM and Dean-Stark studies have contributed to a better understanding of the spatial distribution of water within the flocculated sediment and their response to the polymer behaviour at varying graft densities. The effect of increasing the polymer graft density has led to a decrease in the dewatering rate with an increase in the amount of intra-floc water in the MFT sediment post flocculation. This approach clarifies that the flocculant's design, as understood from the spatial distribution of the water, plays a significant part in influencing the water release and water-retention ability of the flocs.
- ItemOpen AccessExperimental Simulation and Life Cycle Assessment Study of the Dense Hot Fluid Injection Process(2016-02-03) Hovsepian, Christian Nubar; Pereira-Almao, Pedro; Bergerson, Joule; Eaton, David; Hejazi, Hossein; Nassar, NashaatThe rapid decline in international oil prices forced oil and gas industries to reduce costs, improve productivity and layoff thousands of employees. Specifically, the majority of resources located in Alberta require thermal recovery methods due to their heavy characteristics. Innovation is required to displace current extraction methods that are becoming economically challenging. The present work studies the dense hot fluid injection (DHFI) process, which targets the in situ catalytic upgrading and extraction of Athabasca bitumen. A bench-scale set up was designed and built. The experimental results were integrated using process simulation and life cycle assessments (LCA) techniques to estimate GHG emissions of the new technology. Results confirmed quality improvement of the feedstock while maintaining a stable product. The experimental setup proved differences in the heat distribution profiles between SAGD and the DHFI. LCA demonstrated that the DHFI could produce less GHG emissions than SAGD under a set of assumed scenarios.
- ItemOpen AccessExperimental Study of Highly-Viscous Vertical Pipe Flow Using a Non-Intrusive Multi-View Measurement Technique(2021-06-30) Solis Meza, Miriam; Hugo, Ronald J.; Mohamad, Abdulmajeed; Nassar, NashaatIn this study, a non-intrusive multi-view measurement technique is used for tracking ascending air bubbles in a highly-viscous fluid (glycerin) and for tracking the injection of a lower-density mixture into a vertical flow of glycerin. Digital image processing was used to reduce light reflection due to back illumination in the multi-view measurement system. Combinations of convolution kernels and thresholding methods perform boundary detection, light reflection corrections and geometrical parameter measurements in the software ImageJ (Fiji). Receiver Operating Characteristics (ROC) plots based on a True Positive Rate (TPR) analysis are used to statistically quantify the effectiveness of the boundary detection and the light reflection reduction. The experimental scenarios in this study include: an opaque solid sphere ascending in a continuous highly-viscous liquid, air bubbles rising in a continuous highly-viscous liquid (glycerin), air bubbles rising in a stratified fluid with dense glycerin capped by a less dense 50%(w) water-glycerin mixture, and a colored 50%(w) water-glycerin mixture injected into a vertical flow of glycerin. The bubble volume calculation was performed using a “wedge” approximation. Bubble volume had errors as low as -0.3% compared to Ground Truth data. For the experiment of the injection of a colored 50%(w) water-glycerin mixture, light intensity analysis was examined as a method to determine parameters of injected liquid including position, length and segmentation which has the potential to be applied to the study of drag-reducing agent injection into a bulk flow.
- ItemEmbargoFundamental Understanding of the Cathodic Catalyst Layer of an Anion Exchange Membrane-Based CO2 Electrolyzer: Catalyst Optimization and Ionomer Characterization(2023-09-20) Alihosseinzadeh, Amir; Ponnurangam, Sathish; Karan, Kunal; Kusoglu, Ahmet; Mahinpey, Nader; Nassar, Nashaat; Roberts, Edward (Ted)CO2 electrolysis exhibits significant potential in addressing climate change and facilitating the transformation of captured CO2 into valuable chemicals and fuels. Recent years have witnessed remarkable advancement in the design of CO2 electrolyzers, offering future commercial viability. These design advancements encompass cell configuration, catalytic materials for the cathode and anode, as well as suitable membranes and ionomers. This thesis is focused on the cathodic catalyst layer (CCL) of a gas-fed anion exchange membrane-based CO2 electrolyzer, a pivotal component. The CCL consists of a porous nanocomposite structure comprising electrocatalyst coated with a nanothin ionomer film. The pores facilitate CO2 gas transport, the connected network of catalyst allow electron transport, the percolated distribution of ionomer ensures ion diffusion, the ionomer coverage of catalyst provides the required electrochemical interface and together these features provide for efficient electrochemical reactions. Specifically, the work targeted on optimizing an Ag-based catalyst for CO production and characterizing an imidazolium-based anion exchange ionomer within the CO2 electrolysis environment. While prior research mostly employed highly loaded (1-3 mg.cm-2) commercial Ag nanoparticles, which is spray-coated on the electrode with a maximum mass-specific activity of around 100-150 mA.mgAg-1, this study introduces an electrodeposition technique to synthesize Ag catalysts. This technique not only enhances the electrical contact with the substrate, but also enables control over catalyst size, morphology, and crystallography, which influences catalyst performance and catalyst utilization. Various Ag electrodes with distinct sizes and structures, ranging from polycrystalline to dendritic, were synthesized and assessed for CO2 reduction. An optimized dendritic Ag catalyst, with 0.29 mg.cm-2 Ag loading and maximum (220)/(111) facet ratio, exhibited a high mass-specific activity of 362 mA.mgAg-1, current density of 105 mA.cm-2, and 94% CO selectivity at a 3 V cell potential, maintaining robust performance over extended 100 h CO2 reduction reaction. The catalyst/ionomer interface plays a pivotal role in CO2 reduction, necessitating not only highly electrochemically-active sites to maximize catalyst performance, but also optimized CCL microstructure for ion transport to minimize catalyst utilization. The characteristics of an imidazolium-based anion exchange ionomer (Sustainion, XA-9) were probed under CO2 electrolysis conditions. The influence of relative humidity (0-95%), film thickness (8-61 nm), chemical environment (N2 vs CO2 exposure), and ionomer counterion exchange (Cl- to OH-) on hydration properties, ionic conductivity, and CO2 adsorption/reduction was investigated. Results reveal that swelling, water content (λ), and ionic conductivity of the ionomer films in Cl- form (XA9-Cl), increase with rising relative humidity, with a confinement behavior observed below 26 nm thickness; (22% swelling, 32 wt.% water content, and 13 mS.cm-1 ionic conductivity, at 95% RH on a 26 nm thick film). Although the CO2 exposure did not change the swelling properties of the XA9-Cl ionomer thin film, the water content was slightly increased due to the carbonate/bicarbonate formation in the ionomer. The ionic conductivity of the XA9-Cl thin film responds differently in the N2 vs CO2 chemical environment, displaying a crossover at λ > 6. CO2-exposed ionomer films exhibit higher conductivity at lower λ but lower conductivity at higher λ compared to N2-exposed films. This phenomenon could arise from bicarbonate species enhancing ion conductivity at lower λ, while exhibiting reduced mobility and conductivity compared to OH- ions under high humidity conditions. The transformation of the ionomer to its OH- form improves swelling, water content, and ionic conductivity, reaching levels of 26%, 36 wt.%, and 33 mS.cm-1, respectively, at 95% RH on a 26 nm thin film. Moreover, the OH- form ionomer demonstrates improved CO2 adsorption and reduction on an Au electrode, confirmed by CV analysis. Nevertheless, thicker films manifest postponed CO2 reduction owing to transport limitations in the ionomer film.
- ItemOpen AccessGreenhouse Gas Emissions from Natural Gas Development in Western Canada: A Gap Analysis(2016) Senobari Vayghan, Elnaz; Bergerson, Joule; Ponnurangam, Sathish; Nassar, NashaatThe greenhouse gas (GHG) emissions of conventional and unconventional natural gas are primarily methane and carbon dioxide that are released in natural gas development activities. Addressing these emissions have gained attention because of recent climate commitments. Life Cycle Assessment (LCA) can help to compare different pathways of gas development considering all life cycle stages. The objective of this thesis is to conduct a LCA of GHG emissions of natural gas in western Canada, with a focus on BC`s Montney and Horn River. This thesis presents a gap analysis demonstrating that current public data in Canada is insufficient to characterize the life cycle emissions and highlighted where the data is needed. Preliminary estimates suggest that the average US unconventional gas life cycle emissions are higher than those in Canada but significant variability exists between and within regions of Canada. Future investigation and data collection is required to confirm these preliminary results.
- ItemOpen AccessMagnetic Microgels: Design, Synthesis, and Application(2024-04-30) Afsar, Faranak; Bryant, Steven; Hu, Jinguang; Trifkovic, Milana; Nassar, Nashaat; Clarkson, Christopher; Trivedi, JapanMagnetite nanoparticles (NPs) have shown promising potential for different applications including drug delivery, magnetic resonance imaging, environmental remediation, and catalysis. However, the main challenge limiting the magnetite NP applicability is its tendency to aggregate. As a result, a lot of research has been conducted on magnetite NP stabilization to improve their suitability for different applications. This thesis goal was to investigate the incorporation of magnetite NPs into microgels as a stabilization technique of the magnetite NPs and evaluate the magnetite NP-microgel hybrid system for two specific applications I) magnetic reservoir monitoring, and II) Lead removal from water. Microgels based on poly(N-isopropyl acrylamide) (PNIPAM) containing different mole ratios of methacrylic acid (MAA) were designed as templates for the in-situ synthesis and incorporation of magnetite NPs. Subsequently, microgel colloidal stability regarding NaCl concentration and temperature was studied to assess their applicability for subsurface applications. It was shown that microgels with a PNIPAM/MAA mole ratio of 40/60 remained stable at elevated temperatures (80 °C) and salinity (up to 10 wt% NaCl) which makes them suitable for subsurface applications. Additionally, the core-flooding experiment indicated that the magnetite NPs-microgel is magnetically detectable and does not have permanent retention in the porous medium. The obtained results show that magnetite NP-PNIPAM-co-MAA microgel has great potential as a magnetic contrast agent for reservoir monitoring. Magnetite NPs incorporated into the PNIPAM microgel were used as adsorbent for Pb2+ removal from water. The designed adsorbent was efficient in Pb2+ removal from water with a maximum capacity of 46 mg Pb2+/g. The results indicated that using microgels as carriers for magnetite NPs is an effective method for adsorption applications due to the porous structure of the microgels which facilitates high mass exchange between magnetite NPs and aqueous medium. In conclusion, results obtained from this study show that the magnetite NP-microgel hybrid system as a multifunctional material provides design flexibility to create materials for applications in various fields including but not limited to lead uptake from water and magnetic reservoir monitoring.
- ItemOpen AccessMeasurements of Binary Molecular Diffusion and Dispersion Coefficients of Urea and Ethyl Acetate(2022-05-27) Kheirollahi, Shadi; Hassanzadeh, Hassan; Nassar, Nashaat; Natale, GiovanniantonioThe environmental impact of in-situ thermal bitumen recovery methods from oil sands has motivated the search for new solvents/chemicals to reduce energy intensity and greenhouse gas emissions. Recently, new solvents/chemicals have been examined on the laboratory and field-scale for co-injection with steam or hot water. However, the fate of the proposed chemicals/solvents in the subsurface has not been studied. Diffusion and dispersion coefficients of the injected chemicals are two important transport properties required to predict the fate of the injected solvents in the subsurface. Ethyl acetate and urea are among the chemicals that have been suggested to improve bitumen recovery from oil sands. However, there is a lack of accurate measurements of the diffusion and dispersion coefficients of these chemicals. To fill this gap, the longitudinal dispersion coefficients of binary liquid mixtures of ethyl acetate and urea were measured using the Taylor dispersion technique at various concentrations of solute and several flow rates by performing a series of displacement experiments through the sand-packed bed. New measurements of the concentration-dependent longitudinal dispersion coefficients in porous media of aqueous urea solution and ethyl acetate-water mixture are reported. In addition, experimental data for the binary diffusion coefficients of ethyl acetate-water systems over the entire range of compositions at temperatures from 298.15 K to 368.15 K are reported.
- ItemOpen AccessMechanistic Simulation of Solvent-aided Gravity Drainage of Bitumen(2017) Salas Santa, Marta Liliana; Hassanzadeh, Hassan; Moore, Robert; Nassar, NashaatThe injection of solvent is an alternative method for recovering heavy oil and bitumen to reduce the viscosity and density of the bitumen. In this study, solvent assisted thermal gravity drainage is modelled in CMG STARS using propane as the solvent. First, the modeling of thermosphysical properties of bitumen and propane mixture was performed. Then, a highly refined and simple mechanistic model was constructed and validated. The parameters of the model were defined to enable the numerical model for pure mass and heat transfer as well as coupled heat and mass transfer processes. Three mechanistic cases were studied including isothermal gravity drainage, non-isothermal gravity drainage, and solvent-aided non-isothermal gravity drainage. Also, three groups were defined to obtain a better understanding of the effect of the bitumen properties and the relative permeability curves on the drainage process. Group 1 with low initial bitumen viscosity, Group 2 with high initial bitumen viscosity, and for Group 3 with different relative permeability models were studied. Fine grid numerical simulations demonstrated extensive fingering during the drainage process and the need for fine grid numerical simulations to ensure accurate capturing the physics of gravity drainage. Scaling relations were developed to describe the rate of oil drainage as a function governing dimensionless groups. For the isothermal gravity drainage, the presence of the solvent (propane) and its molecular diffusion into bitumen was found to play a critical role in reducing the viscosity and density of the bitumen leading to gravity drainage of bitumen.
- ItemOpen AccessNano-Pyroxene for Adsorption and Catalytic Thermal Decomposition of Visbroken Residue Asphaltenes(2016) Hmoudah, Maryam; Nassar, NashaatOil will continue to be a major source of future non-renewable energy, and hence new cost-effective technologies for upgrading and recovery of conventional and unconventional oils are needed. This study presents a new environmentally sound and low-cost, yet highly efficient pyroxene nanoparticles (NaFeSi2O6, PY). Low temperature hydrothermal synthesis route was used to prepare different sized and surface-structural-modified PY nanoparticles, which were characterized by different characterization techniques like XRD, BET, FTIR, TGA, TPD-CO2, TPD-NH3, XPS, SEM and HRTEM. These nanoparticles were applied for the adsorptive removal of violanthrone-79 (VO-79) as an asphaltene model molecule. The adsorption isotherms were described by the Sips isotherm model. Similarly, the prepared nanoparticles were employed for the adsorptive removal of visbroken residue (VR-C5) asphaltenes, and the solid-liquid-equilibrium (SLE) model was used to describe the adsorption isotherms. The promising catalytic effect of PY nanoparticles towards adsorbed VR-C5 asphaltenes was investigated using TGA coupled with mass spectrometry.
- ItemOpen AccessPhosphonium-Enhanced Chitosan for Hexavalent Chromium Adsorption in Wastewater Treatment(2017) Sessarego, Sebastian; Hill, Josephine; Nassar, Nashaat; Lu, Qingye (Gemma)Adsorption is a commonly used technique for removing contaminants from wastewater, such as hexavalent chromium (Cr(VI)) from the wastewater of a chrome plating plant. Chitosan, a prevalent polymeric biomass that is used industrially as a wastewater treatment adsorbent, was crosslinked and functionalized with a low-cost phosphonium salt to enhance its adsorption capacity for Cr(VI). At Cr(VI) concentrations below 130 ppm, the phosphonium-crosslinked chitosan (PCC) adsorbed more than double the amount of Cr(VI) than the unmodified chitosan. The low-cost method for manufacturing PCC may provide a cost-effective alternative to simply increasing the amount of chitosan used in a process. Additionally, PCC was regenerated using magnesium sulfate for repeated use. The recovered Cr(VI) may be recycled back into a chrome plating process.
- ItemOpen AccessRole of Nanosize Effects on the Adsorptive and Catalytic Properties of NiO Nanoparticles towards Heavy Hydrocarbons(2016) Marei, Nedal Nael; Nassar, Nashaat; Kallos, Michael; Bergerson, JouleThe effect of NiO nanoparticle size was studied to understand its impact on adsorption and catalytic activity during oil recovery and upgrading. A series of different-sized NiO nanoparticles between 5 and 80 nm were prepared. XRD, BET, FTIR, HRTEM and TGA were used to characterize the nanosize effect on the textural properties, shape and morphology. Quinolin-65 (Q-65) was first used as an asphaltene model molecule. Langmuir and Freundlich adsorption isotherms models and computational modeling for the interaction between NiO nanoparticle surface and Q-65 were carried out to understand the adsorption behavior. TGA/DTA and TGA-MS techniques were used to study the effect of NiO nanosizes on catalytic thermo-oxidative decomposition of the adsorbed Q-65. The entire study was repeated using visbroken residue n-C5 asphaltenes. For both Q-65 and n-C5 asphaltene post-adsorption oxidation, the Kissinger-Akahira-Sunose (KAS) kinetic method was used to estimate the kinetic triplets, namely f (α), Eα and Aα.
- ItemOpen AccessSplit-Flow Integrated Small-Scale LNG Production Process with Cryogenic Carbon Dioxide Capture(2020-09-28) Ostovar, Arash -; Nassar, Nashaat; Hassanzadeh, Hassan; De la Hoz Siegler, HectorThis thesis addressed three challenges facing the processing of natural gas. First, energy is usually required to produce energy, but it takes more energy to produce liquified natural gas (LNG) than other fossil fuels. In other words, LNG production is a very energy-intensive process, which makes it less competitive. Second, many cryogenic NGL-recovery facilities have been working under full capacity due to low natural gas prices and limited accessible new markets. The last challenge concerns the classic aqueous alkanolamine-based sweetening process, which involves saturating gas with water and restricting the LNG production temperature to be begin from ambient temperature and needs a finishing process to handle the produced acid gas.With a view to address these challenges, first, a novel integrated small-scale LNG process concept was developed that can not only maximize the economic value of NGL recovery facilities but also produce LNG via a more efficient and greener process. This was achieved through comprehensive process simulations, optimizations, and heat integration studies. These studies were performed using the Aspen HYSYS simulation package to find an efficient integrated LNG production process that can use available sources of heating/cooling in a cryogenic NGL-recovery facility without sacrificing the NGL production yield. In the development process, it was determined that an adsorption process (nonsolvent) can remove CO2 at cryogenic temperatures and treat natural gas with the aim of meeting the LNG specification (CO2=50 ppm). This led me to the development of the “split-flow integrated small-scale LNG production process (SFI-LNG)”, which has two main pillars—the cryogenic CO2 removal process and the semi-C3-MR liquefaction process.Second, to validate the cryogenic removal of CO2, zeolite-based adsorbents were synthesized and characterized before they were successfully tested under cryogenic conditions.Third, a bench-scale experimental setup was designed and constructed to prove the concept of cryogenic CO2 removal. Finally, the concept was proven at the bench scale.The principle of cryogenic CO2 removal is based on the selective adsorption of CO2 by a Faujasite (FAU)-based adsorbent under cryogenic conditions, which exhibits a high adsorption rate with great recyclability. In addition, there is no need for a finishing process to deal with acid gas, as highly pure CO2 can be produced as a byproduct.
- ItemOpen AccessSynthesis and Characterization of Modified Nanoclay for Polymer Nanocomposite Applications(2017) Asgari, Mohammad; Sundararaj, Uttandaraman; Nassar, Nashaat; Sudak, Leszek Jozef; Husein, Maen; Ajji, AbdellahPolymer nanocomposites (PNCs) have several advantages, such as excellent mechanical properties, lightweight, durability, easy process-ability and low cost due to nanofiller high surface area. The main objective of this PhD thesis is to develop modified nanoclays for PNC, particularly high density polyethylene (HDPE) PNCs with enhanced mechanical and thermal properties. This has been accomplished by modifying the nanofiller constituents and optimizing the fabrication and processing methods. Different techniques for modifications were used depending on the end-use applications of the nanocomposites. These techniques were built upon a comprehensive understanding of the nanofiller structure and the modification type for PNC applications. The synthesized nanofiller and the nanocomposite’s final properties were investigated, and mechanical, thermal and rheological performance were characterized for PNC. In this PhD thesis, different nanoclays were synthesized and used as nanofiller in high density polyethylene. The resulting nanocomposites showed improvement in some mechanical and thermal properties. Different strategies were employed: (1) modification of nanofillers, (2) synthesis of novel nanofillers, (3) use of hybrid filler systems, and (4) and optimization of the processing conditions. For nanofiller modification, we performed chemical treatment of nanoclay and synthesis of hybrid clay/CNT. Functionalized clay was synthesized using silane coupling agents to take advantage of high thermal resistance of the silane coupling agents over traditionally used surfactants. The silane modified clay was further functionalized in a second reaction. The main objective of these strategies was to improve the affinity of polymer with clay, and increase interlayer space, and consequently, to increase dispersion of nanofillers in the host polymer to enhance PNC properties. Utilizing a secondary filler to further enhance the desired properties was another strategy. This was accomplished by synthesizing in situ hybrid CNT/clay nanofiller; that is, CNT was synthesized using CVD process directly on the clay silicate surface. Finally, we optimized PNC production methods (e.g., melt mixing, catalyst synthesis and clay functionalization). The aim of the last two strategies was to obtain improved mechanical and physical properties for the nanocomposite, and it is well known that nanocomposite structure can be used to control the final PNC properties.