Browsing by Author "Zhang, Zhuqing"
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Item Application of magnetic nanoparticles as demulsifiers for surfactant-enhanced oil recovery(Wiley, 2023) Zhang, Leilei; Bai, Chutian; Zhang, Zhuqing; Wang, Xinglin; Nguyen, Thao Vy; Vavra, Eric; Puerto, Maura; Hirasaki, George J.; Biswal, Sibani LisaNonionic surfactants are increasingly being applied in oil recovery processes due to their stability and low adsorption onto mineral surfaces. However, these surfactants lead to the production of emulsified oil that is extremely stable and difficult to separate by conventional methods. This research characterizes the stability of crude oil mixed with a nonionic surfactant, L24–22, in a brine solution. When subjected to gravity separation, a middle oil-rich and bottom water-rich emulsion are generated for various water–oil ratios. Thermal treatments can effectively break oil-rich emulsions, but the bottom water layer remains contaminated with micron-sized crude oil droplets. A magnetic nanoparticle treatment is shown to demulsify the crude oil emulsions, dropping the total organic carbon (TOC) in the water layer from 1470 to 30 ppm.Item Characterizing Asphaltene Related Flow Assurance Problems with Microfluidics(2022-04-22) Zhang, Zhuqing; Biswal, Sibani LisaAsphaltene deposition and emulsion plugging are significant contributors to oil production and transportation flow assurance problems. A better understanding of the physicochemical aspects of asphaltenes, such as their interfacial and transport properties, is required to better design industrial macroscale processes. Microfluidics has emerged as a new method to evaluate complex fluid flow in confined geometries. Also, microfluidic devices can capture the critical characteristics of reservoir rocks and provide novel insights into the transport, reactions, and chemical interactions governing fluids used in the oil and gas industry. Dual-perm and natural porous mimic microfluidic designs are applied to represent various flow conditions typically found in oil flow processes. High efficient, economically feasible solutions, including non-toxic microemulsion formulations, polymer-grafted nanoparticles, and chemical inhibitors, are designed for asphaltene mitigation and remediation. Furthermore, the organization of asphaltenes on interfaces is studied, using asphaltene mimic molecules as a comparison to natural asphaltenes to better understand emulsion stability. We provide insight to better design industrial treatment for crude oil demulsification and oil-water separation through a deeper understanding of asphaltene behaviors at interfaces.Item Characterizing the Influence of Organic Carboxylic Acids and Inorganic Silica Impurities on the Surface Charge of Natural Carbonates Using an Extended Surface Complexation Model(American Chemical Society, 2019) Song, Jin; Rezaee, Sara; Zhang, Leilei; Zhang, Zhuqing; Puerto, Maura; Wani, Omar B.; Vargas, Francisco; Alhassan, Saeed; Biswal, Sibani L.; Hirasaki, George J.In this work, we developed an extended surface complexation model (SCM) that successfully fits all tested ζ-potential data (63 in total) of synthetic calcite and three natural carbonates (Iceland spar, Indiana limestone, “SME” rock from a Middle East field) in brines with divalent ions in a wide range of ionic strengths (0.001–0.5 M). To develop this extended model, our previous reported SCM is first optimized by incorporating the ζ-potential of synthetic calcite in a wide range of ionic strength (0.001–0.5 M) along with previously published data for parameter refitting. The model is then applied to predict the surface charge of synthetic calcite in concentrated solutions up to 5 M NaCl to reveal the role of high salinity in calcite wettability. Eventually, the model is extended to fit the ζ-potential of natural carbonates by adding surface reactions for impurities such as silica and organic-based carboxylic acids. The coverage of the organic impurities is found to be essential for explaining why the ζ-potential of natural carbonates is more negative compared to that of synthetic calcite. Naphthenic acid (assumed to have one carboxylic group) and humic/fulvic acid (assumed to have six carboxylic groups) are tested in the model calculation as possible sources of surface impurities to demonstrate the effect of the number of carboxylic groups in the acid molecule. Finally, the effect of a humic acid pretreatment on the ζ-potential of synthetic calcite is investigated experimentally to verify the assumption that absorbed organic impurities on the calcite surface contribute significantly to a more negatively charged natural carbonate surface when compared to that of pure calcite surfaces.Item Coalescence of Model Asphaltene-Stabilized Water-in-Oil Emulsions in Microfluidic Devices(2018-04-20) Zhang, Zhuqing; Biswal, Sibani LisaAsphaltene related problems have aroused more and more attention in flow assurance and proved to be fatal with practical examples in both oil production and transportation. Asphaltene-stabilized emulsions generated in the oil recovery would significant increase oil viscosity which leads to a giant energy loss during the transport process. Meanwhile, oil sources containing emulsions need extra treatments to separate residual water before being converted to petrochemical products. In order to find better solutions to breaking those unexpected emulsions sufficiently, detailed information about asphaltene-stabilized emulsions was needed. Since the chemical structure of asphaltene was still buried in mystery, we decided to utilize model molecules to mimic the field asphaltene molecules at oil-water interface, and try to investigate the mechanism of how asphatlenes stabilize emulsions. In this work, model molecules, coronene and VO-79, were used as references, and emulsion stability was characterized using microfluidic method. Interfacial properties of model asphaltene molecules were also studied with interfacial tension (IFT) measurement and surface potential measurement.Item Combined interfacial shear rheology and microstructure visualization of asphaltenes at air-water and oil-water interfaces(The Society of Rheology, 2018) Lin, Yu-Jiun; Barman, Sourav; He, Peng; Zhang, Zhuqing; Christopher, Gordon F.; Biswal, Sibani LisaAsphaltenes are surface-active polyaromatic molecules in crude oil that are known to deposit in pipelines or stabilize water droplets by flocculating at interfaces resulting highly viscous emulsions, leading to significant flow assurance problems. Commercial dispersants have been developed to disturb asphaltene aggregation to mitigate deposition, but their role on the interfacial properties of asphaltene films is unclear. In this study, we elucidate asphaltene interfacial rheology at air-water and oil-water interfaces at high and low asphaltene surface coverage and in the presence of dispersants. A modified Langmuir trough with double-wall ring rheometer is used to simultaneously visualize the microstructure of asphaltene interface and measure the rheological responses. Two surface coverages, 0.5 and 4 μg cm−2, show widely different rheological responses at air-water interfaces. Strong yielding behavior was observed for higher coverage while a less yielding behavior and wider linear viscoelastic regime were observed for the lower coverage. Additionally, asphaltenes at decane-water interfaces were less shear-thinning than at air-water interfaces. Surface pressure-area compression-expansion curves show that the interface is more compressible in the presence of commercial chemical dispersants. This combined imaging and interfacial rheology platform provide an effective method to correlate asphaltene microstructure to interfacial rheological properties.Item Evaluation of Asphaltene Remediation Using Microemulsion Formulations in a Porous Media Microfluidic Device(American Chemical Society, 2021) Zhang, Zhuqing; Perrard, Alyssa; Trabelsi, Siwar; Biswal, Sibani LisaThis article presents a comparison of the efficiency of d-limonene to other solvent-based microemulsions (MEs) for the removal of asphaltene deposits using a dual-permeability porous media microfluidic device. The dynamics of removal of the deposited asphaltenes were analyzed using optical microscopy and in situ pressure-drop measurements. All MEs tested showed a higher asphaltene removal efficiency when compared to the control ME formulation, a surfactant package without a solvent. The amount and rate of asphaltene removal were strongly dependent on the type and amount of solvent contained within the ME. The dynamics of the asphaltene removal for the most effective formulations were fit to a pseudosecond-order desorption kinetic model. The results support a mechanism wherein the MEs solubilize the asphaltene deposits.Item Patterning, Transfer, and Tensile Testing of Covalent Organic Framework Films with Nanoscale Thickness(American Chemical Society, 2021) Zhu, Dongyang; Hu, Zhiqi; Rogers, Tanya K.; Barnes, Morgan; Tseng, Chia-Ping; Mei, Hao; Sassi, Lucas M.; Zhang, Zhuqing; Rahman, Muhammad M.; Ajayan, Pulickel M.; Verduzco, RafaelCovalent organic frameworks (COFs) are promising materials for a variety of applications, including membrane-based separations, thin-film electronics, and as separators for electrochemical devices. Robust mechanical properties are critical to these applications, but there are no reliable methods for patterning COFs or producing free-standing thin films for direct mechanical testing. Mechanical testing of COFs has only been performed on films supported by a rigid substrate. Here, we present a method for patterning, transferring, and measuring the tensile properties of free-floating nanoscale COF films. We synthesized COF powders by condensation of 1,3,5-tris(4-aminophenyl)benzene (TAPB) and terephthalaldehyde (PDA) and prepared uniform thin films by spin casting from a mixture of trifluoroacetic acid and water. The COF films were then reactivated to recover crystallinity and patterned by plasma etching through a poly(dimethylsiloxane) (PDMS) mask. The films were transferred to the surface of water, and we performed direct tensile tests. We measured a modulus of approximately 1.4 GPa for TAPB-PDA COF and a fracture strain of 2.5%, which is promising for many applications. This work advances the development of COFs for thin-film applications by demonstrating a simple and generally applicable approach to cast, pattern, and transfer COF thin films and to perform direct mechanical analysis.Item Rapid, Ambient Temperature Synthesis of Imine Covalent Organic Frameworks Catalyzed by Transition-Metal Nitrates(American Chemical Society, 2021) Zhu, Dongyang; Zhang, Zhuqing; Alemany, Lawrence B.; Li, Yilin; Nnorom, Njideka; Barnes, Morgan; Khalil, Safiya; Rahman, Muhammad M.; Ajayan, Pulickel M.; Verduzco, RafaelCovalent organic frameworks (COFs) are crystalline, porous organic materials that are promising for applications including catalysis, energy storage, electronics, gas storage, water treatment, and drug delivery. Conventional solvothermal synthesis approaches require elevated temperatures, inert environments, and long reaction times. Herein, we show that transition-metal nitrates can catalyze the rapid synthesis of imine COFs under ambient conditions. We first tested a series of transition metals for the synthesis of a model COF and found that all transition-metal nitrates tested produced crystalline COF products even in the presence of oxygen. Fe(NO3)3·9H2O was found to produce the most crystalline product, and crystalline COFs could be produced within 10 min by optimizing the catalyst loading. Fe(NO3)3·9H2O was further tested as a catalyst for six different COF targets varying in linker lengths, substituents, and stabilities, and it effectively catalyzed the synthesis of all imine COFs tested. This catalyst was also successful in the synthesis of 2D imine COFs with different geometries, 3D COFs, and azine-linked COFs. This work demonstrates a simple, low-cost approach for the synthesis of imine COFs and will significantly lower the barrier for the development of imine COFs for applications.