Letteratura scientifica selezionata sul tema "Gas-Solid interface stability"
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Articoli di riviste sul tema "Gas-Solid interface stability":
1
Zhang, Di. "Investigation of the Zeta Adsorption Model and Gas-Solid Adsorption Phase Transition Mechanism Using Statistical Mechanics at Gas-Solid Interfaces". Adsorption Science & Technology 2023 (15 novembre 2023): 1–16. http://dx.doi.org/10.1155/2023/8899160.
Abstract (sommario):
This review examines the significance of the zeta adsorption model in physics and its integration with statistical mechanics within the field of interface adsorption. Through a comprehensive analysis of existing research, this study presents the collective findings and insights derived from the reviewed literature. The zeta adsorption model, proposed by Ward, has gained recognition for its seamless extension into the thermal disequilibrium region without encountering singularities. By incorporating principles from quantum mechanics and statistical thermodynamics, this model offers fresh perspectives on the adsorption of gas molecules on solid surfaces. Notably, it demonstrates enhanced accuracy in describing the adsorption performance of mesoporous materials and nanomaterial surfaces, surpassing the limitations of traditional models such as the BET isotherm. Additionally, this review explores the behavior of cluster formation under varying temperature and pressure conditions. It highlights the correlation between increasing pressure ratios and the decreased availability of empty adsorption sites, resulting in the formation of larger clusters within the adsorbate. Ultimately, this process leads to a transition from adsorption to condensation, where the liquid phase wets the solid surface. Moreover, the zeta adsorption model provides a solid theoretical foundation for understanding crucial aspects of gas-solid interface adsorption. It enables the determination of the distribution of adsorbate clusters on gas-solid interfaces, facilitates the identification of wetting pressure ratios during phase transitions, and allows for the calculation of solid surface tension under conditions of zero adsorption. Noteworthy parameters such as the bonding strength (β) between the solid surface and adsorbed atoms significantly influence the overall strength of the solid-fluid interaction. Furthermore, the phenomenon of surface subcooling, which necessitates sufficient energy for the transformation from adsorbed vapor to condensate liquid, plays a pivotal role in studying interface phase transitions. Additionally, this review investigates the thermodynamic stability of the adsorbate through an analysis of molar latent heat. It reveals that beyond a critical adsorbate coverage, the formation of critical-sized clusters and the ensuing interactions among these components render the adsorbate unstable. This instability prompts a transition from the interface to a liquid phase, followed by subsequent adsorption onto the surface. In summary, this literature review highlights the significant contributions of the zeta adsorption model to the field of physics, particularly in the context of interface adsorption. It serves as a valuable tool for studying various materials and cluster formation, thanks to its seamless extension into the thermal disequilibrium region and its incorporation of principles from quantum mechanics and statistical thermodynamics. By presenting a synthesis of existing research, this review sheds light on the advantages of the zeta adsorption model and paves the way for further investigations into gas-solid interface adsorption phenomena.
2
Kang, Seul-Gi, Dae-Hyun Kim, Bo-Joong Kim e Chang-Bun Yoon. "Sn-Substituted Argyrodite Li6PS5Cl Solid Electrolyte for Improving Interfacial and Atmospheric Stability". Materials 16, n. 7 (29 marzo 2023): 2751. http://dx.doi.org/10.3390/ma16072751.
Abstract (sommario):
Sulfide-based solid electrolytes exhibit good formability and superior ionic conductivity. However, these electrolytes can react with atmospheric moisture to generate H2S gas, resulting in performance degradation. In this study, we attempted to improve the stability of the interface between Li metal and an argyrodite Li6Ps5Cl solid electrolyte by partially substituting P with Sn to form an Sn–S bond. The solid electrolyte was synthesized via liquid synthesis instead of the conventional mechanical milling method. X-ray diffraction analyses confirmed that solid electrolytes have an argyrodite structure and peak shift occurs as substitution increases. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses confirmed that the particle size gradually increased, and the components were evenly distributed. Moreover, electrochemical impedance spectroscopy and DC cycling confirmed that the ionic conductivity decreased slightly but that the cycling behavior was stable for about 500 h at X = 0.05. The amount of H2S gas generated when the solid electrolyte is exposed to moisture was measured using a gas sensor. Stability against atmospheric moisture was improved. In conclusion, liquid-phase synthesis could be applied for the large-scale production of argyrodite-based Li6PS5Cl solid electrolytes. Moreover, Sn substitution improved the electrochemical stability of the solid electrolyte.
3
Zakaria, K. "Kelvin--Helmholtz instability of a horizontal interface between a finite subsonic gas and a finite magnetic liquid". Canadian Journal of Physics 76, n. 5 (1 maggio 1998): 361–74. http://dx.doi.org/10.1139/p98-006.
Abstract (sommario):
The nonlinear Kelvin-Helmholtz instability of a horizontal interface between a magnetic inviscid incompressible liquid and an inviscid laminar subsonic gas is investigated. The gas and the liquid are assumed to have finite thicknesses. The applied magnetic field is parallel to the solid surfaces of the considered system. The method of multiple scales is used to obtain two nonlinear Schrodinger equations describing the behaviour of the perturbed system. The stability of the progressive waves is discussed theoretically. The nonlinear cutoff wave number is obtained, where the stability conditions of the standing waves are obtained. A numerical example is applied to discuss the stability diagrams.PACS Nos.: 51.60 and 47.20
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Zheng, Miaozi, Renjie Yang, Jianmin Zhang, Yongkai Liu, Songlin Gao e Menglan Duan. "An Interface Parametric Evaluation on Wellbore Integrity during Natural Gas Hydrate Production". Journal of Marine Science and Engineering 10, n. 10 (18 ottobre 2022): 1524. http://dx.doi.org/10.3390/jmse10101524.
Abstract (sommario):
Based on the whole life cycle process of the economic exploitation of natural gas hydrate, this paper proposes the basic problem of stabilizing the wellbore for the basic conditions that must be met to ensure the integrity of the wellbore for exploitation: revealing the complex mechanism of fluid–solid–heat coupling in the process of the physical exchange of equilibrium among gas, water, and multiphase sand flows in the wellbore, hydrate reservoir, and wellbore, defining the interface conditions to ensure wellbore stability during the entire life cycle of hydrate production and proposing a scientific evaluation system of interface parameters for wellbore integrity.
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Shao, Xiaohan, Qianhong Zhu, Ting Wang, Mourin Jarin, Xing Xie e William Abraham Tarpeh. "Probing Bubble Properties during Hydrogen Evolution Reaction on Platinum Micropatterns Using Scanning Electrochemical Microscopy". ECS Meeting Abstracts MA2023-02, n. 54 (22 dicembre 2023): 2634. http://dx.doi.org/10.1149/ma2023-02542634mtgabs.
Abstract (sommario):
Many electrochemical reactions involve gas bubble consumption and generation at liquid-solid interfaces, creating a three-phase interfacial zone (e.g., solid electrode, liquid electrolyte, gaseous products). For example, hydrogen and oxygen evolution reactions (HER, OER) generate gas, the nitrate reduction reaction (NO3RR) makes gaseous and aqueous products, and the carbon dioxide reduction reaction (CO2RR) consumes gas while making gaseous and aqueous products. These reactions correlate gas bubbles to important energy and sustainability applications such as aqueous electrolysis, photoelectrochemical energy storage, environmental catalysis, and water treatment. In electrochemical water treatment, gas bubbles have been shown to catalyze chemical reactions and enhance the efficiency of water treatment by degrading organic pollutants and reducing fouling of water treatment components (e.g., membranes). However, gas bubbles grow into macroscopic sizes after nucleating on solid surfaces, which interferes with chemical processes by blocking the reactants from reaching the liquid-solid interface and impedes reaction rate and energy efficiency. The liquid-solid interface is a critical zone that dictates the performance of electrochemical processes. Bubble formation at the liquid-solid interface also presents a major challenge for establishing molecular understanding of reaction mechanisms, kinetics, stability, and selectivity toward desired products, and therefore complicates process designs that leverage gas bubble properties to facilitate electrochemical reactions. Questions such as how surface bubbles form and grow on surfaces, how they impact chemical reactivity at surfaces, and how electrode geometries (e.g., the size, shape, and arrangement of the catalysts for reactions) guide bubble formation and transport should be answered to inform rational design of electrochemical processes to efficiently utilize the bubbles. In this study, we use HER as a model reaction to probe bubble properties using scanning electrochemical microscopy (SECM) and optical microscopy to gain understandings of the fate and dynamics of bubbles (i.e., nucleation, aggregation, transport, and dissolution). Specifically, we developed and fabricated micro-scale platinum patterned substrates that vary in Pt pattern size (20-200 µm diameter), gap spacing (1-10x diameter apart), and angle (60° and 90°between Pt patterns) to facilitate bubble nucleation. The patterns (120 nm in height) were deposited on n-type silicon wafer (525 µm thickness) using photolithography and electron beam evaporation. We then identified the locations of bubble nucleation on the patterned substrates with optical microscopy. We correlated the locations of bubble formation with the distribution of Pt patterns on the electrode by deconvoluting the measured currents due to bubble aggregation from conductivity of Pt patterns via SECM, a powerful tool to acquire spatial and electrochemical activities for various use cases (e.g., corrosion, catalysis, gas evolution). In addition, we investigated the effects of current densities and reaction time on the nucleation and stability of the bubbles on the fabricated patterned substrates. Furthermore, the lifetime of the patterned substrates was examined, which will provide insights into future engineering design of robust and effective substrates that leverage bubble properties to advance electrochemical water treatment. The results of this study are generalizable to other reactions involving gas bubble generation to enhance optimization and sustainability of other industrial electrochemical processes.
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Jiang, Shi-Kai, Sheng-Chiang Yang, Wei-Hsiang Huang, She-huang Wu, Wei-Nien Su e Bing Joe Hwang. "Basicity and Stability of Argyrodite Sulfide-Based Solid Electrolytes". ECS Meeting Abstracts MA2023-02, n. 8 (22 dicembre 2023): 3278. http://dx.doi.org/10.1149/ma2023-0283278mtgabs.
Abstract (sommario):
Argyrodite-type sulfide-based solid electrolyte Li6PS5Cl (LPSC) holds immense promise for solid-state battery applications. This is attributed to its stable structure and high ionic conductivity. Nonetheless, the persistent challenges involving the instability at the electrode/electrolyte interface and susceptibility to moisture present significant obstacles in material preparation and cell manufacturing processes. Our research has unveiled a noteworthy finding: the sulfur of the PS4 3− moiety is a Lewis-base active site to adsorb Lewis acid. It is found that the adsorption of CO2 on the sulfide electrolytes can enhance both the interfacial and electrochemical stability of the lithium and sulfide electrolyte interface. The formation of new S–CO2 bonds, confirmed using various analytical techniques, plays a pivotal role in modifying the interfacial behaviors of the sulfide electrolytes. Moreover, the LijCO2@LPSCjLTO shows an amazing result, with 62% capacity retention and ultra-high coulombic efficiency of 99.91% after 1000 cycles. Interestingly, the same concept was also applied to the high ionic conductivity sulfide-based superionic conductor Li10GeP2S12 (LGPS) system, which also has the PS4 3− moiety. A novel approach is also developed by utilization of the BBr3 gas as a Lewis base indicator to probe the strength of Lewis basicity of the sulfur sites of sulfide electrolytes. The basicity of the sulfide electrolytes can be correlated to the shift of 11B NMR peak. This correlation is further supported by the H2S generation rate when the electrolyte is exposed to a moisture atmosphere. This work not only provides a new pave towards enhancing stability at the sulfide electrolyte/lithium interface but profound insights into the basicity and moisture stability of sulfide electrolytes.
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Li, Xuefeng, Baojiang Sun, Baojin Ma, Hao Li, Huaqing Liu, Dejun Cai, Xiansi Wang e Xiangpeng Li. "Study on the Evolution Law of Wellbore Stability Interface during Drilling of Offshore Gas Hydrate Reservoirs". Energies 16, n. 22 (15 novembre 2023): 7585. http://dx.doi.org/10.3390/en16227585.
Abstract (sommario):
The study of wellbore stability in offshore gas hydrate reservoirs is an important basis for the large-scale exploitation of natural gas hydrate resources. The wellbore stability analysis model in this study considers the evolution of the reservoir mechanical strength, wellbore temperature, and pressure parameters along the depth and uses plastic strain as a new criterion for wellbore instability. The wellbore stability model couples the hydrate phase transition near the wellbore area under the effect of the wellbore temperature and pressure field and the ‘heat–fluid–solid’ multifield evolution characteristics, and then simulates the stability evolution law of the wellbore area during the drilling process in the shallow seabed. The research results show that, owing to the low temperature of the seawater section and shallow formation, the temperature of the drilling fluid in the shallow layer of the wellbore can be maintained below the formation temperature, which effectively inhibits the decomposition of hydrates in the wellbore area. When the wellbore temperature increases or pressure decreases, the hydrate decomposition rate near the wellbore accelerates, and the unstable area of the wellbore will further expand. The research results can provide a reference for the design of drilling parameters for hydrate reservoirs.
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Safiullin, A. R. "Acoustic stability of a superheated liquid with vapor–gas bubbles". Multiphase Systems 18, n. 1 (maggio 2023): 32–36. http://dx.doi.org/10.21662/mfs2023.1.005.
Abstract (sommario):
It is known that the physicochemical properties of liquids in a metastable state are mainly determined by the presence of various inclusions in their composition, for example, gas bubbles or solid particles, and it has been established that, under mechanical and thermal equilibrium, the state of a liquid with gas bubbles distributed over the volume due to the action of capillary forces at the interface, always overheated. In this paper, we consider the propagation of weak perturbations in a superheated water-air bubbly medium, when, in addition to water vapor, the bubbles contain an inert gas (for example, air) that does not participate in phase transitions. To describe the problems under consideration, a system of equations is used, which consists of the laws of conservation of mass, the number of bubbles, momentum equations, the Rayleigh–Lamb equation, the equation of heat conduction and diffusion. The solution is sought in the form of a damped traveling wave. Based on the solution of the dispersion equation, maps of the stability zones of the systems under consideration were constructed depending on the magnitude of the liquid overheating on the plane ”volume content — bubble radius“.
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Pham, Anh Tuan. "(Invited) Multiscale Modeling of Heterogeneous Interfaces for Hydrogen Production". ECS Meeting Abstracts MA2023-02, n. 48 (22 dicembre 2023): 2409. http://dx.doi.org/10.1149/ma2023-02482409mtgabs.
Abstract (sommario):
Improving performance of hydrogen production devices requires a detailed understanding of physicochemical processes at solid-gas and solid-liquid interfaces. However, probing behavior of these interfaces under working conditions remain a significant challenge for both simulations and experimental techniques. In this talk, I will provide an overview of our strategy for simulating heterogeneous interfaces within the HydroGEN Advanced Water Splitting Materials Consortium, ranging from first-principles calculations of chemical reactivity to machine learning approaches for accelerating theory-experiment integration and continuum methods for understanding microstructure effects. In particular, I will discuss how computational models can be used to elucidate mechanisms of interface chemical reactions and mass transport, as well as the formation of new phases and their impacts on materials stability and performance. I will also show how simulations have been integrated with experimental probes, such as X-ray spectroscopy, to obtain new understanding of materials interfaces under operating conditions. Finally, I will discuss how this understanding is being used to guide new strategies for improving materials functionality for hydrogen production. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
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Guo, Weibin, Yinggan Zhang, Liang Lin, Wei He, Hongfei Zheng, Jie Lin, Baisheng Sa et al. "Enhancing cycling stability in Li-rich Mn-based cathode materials by solid-liquid-gas integrated interface engineering". Nano Energy 97 (giugno 2022): 107201. http://dx.doi.org/10.1016/j.nanoen.2022.107201.
Tesi sul tema "Gas-Solid interface stability":
1
Li, Yalong. "Research on the decomposition characteristics and biosafety of C5F10O/N2/O2 mixed insulating gas". Electronic Thesis or Diss., Orléans, 2023. http://www.theses.fr/2023ORLE1050.
Abstract (sommario):
Dans ce travail de thèse de doctorat, des études expérimentales et théoriques sont réalisées sur les caractéristiques de décomposition du mélange gazeux C5F10O/N2/O2 à l'interface gaz-solide de matériaux métalliques et sous l'action d'une décharge électrique dans un appareil de coupure électrique. La faisabilité et la sécurité de son utilisation sont évaluées en combinaison avec la biosécurité du gaz C5F10O et des produits de décomposition du gaz plasmagène. Compte tenu du contact long entre le mélange gazeux C5F10O/N2/O2 et les matériaux internes de l'équipement de coupure électrique pendant son fonctionnement, la stabilité de l'interaction gaz-solide du mélange gazeux avec les métaux couramment utilisés (cuivre, aluminium et argent), à l'intérieur de l'équipement est caractérisé, et le mécanisme d'interaction gaz-solide entre le mélange gazeux C5F10O et les matériaux métalliques est précisé. Un défaut thermique peut également se produire pendant le fonctionnement de l'équipement. Les caractéristiques typiques de la décharge et de la décomposition par défaut thermique du mélange gazeux C5F10O/N2/O2 contenant différentes concentrations d'oxygène sont identifiées. La composition et les processus de création des produits de décomposition du mélange gazeux sont obtenues, et la corrélation entre les types et le contenu des produits de décomposition caractéristiques et les types de défaut, ainsi que la réaction de l'oxygène vers les produits de décomposition du mélange gazeux C5F10O et le mécanisme d'inhibition de la précipitation des produits solides sont analysés. Sur la base de ce travail, nous proposons un schéma d'optimisation de la stabilité de la couche protectrice argent- cuivre est proposé pour le cuivre avec une faible stabilité gaz-solide du gaz C5F10O/N2/O2. Nous avons défini les produits caractéristiques de la décharge et du défaut thermique du mélange gazeux, ce qui constitue une référence pour la surveillance en ligne des défauts. Nous avons testé la biosécurité du C5F10O et des produits de décomposition par arc. Sa sécurité d'application a été évaluée en fonction des caractéristiques de décharge et de décomposition thermique du mélange gazeux, et des mesures et de protection ciblées et des suggestions sont proposéesIn this doctoral thesis work, experimental and theoretical studies are carried out on the decomposition characteristics of C5F10O/N2/O2 gas mixture at the gas-solid interface of metal materials and under the discharge and thermal action, and the feasibility and safety of its application are evaluated in combination with the biosafety of C5F10O gas and arc decomposition products of C5F10O/N2/O2. Considering the long-term contact between C5F10O/N2/O2 gas mixture and the internal materials of the equipment during normal operation, the gas-solid interaction stability of C5F10O/N2/O2 gas mixture with commonly used metal copper, aluminum and silver inside the equipment is evaluated, and the mechanism of gas-solid interface interaction between C5F10O gas mixture and metal materials is clarified. Discharge and thermal fault may also occur during the long-term operation of the equipment. The failure decomposition mechanism of C5F10O/N2/O2 gas mixture is studied through experiments and simulations. The typical discharge and thermal fault decomposition characteristics of C5F10O/N2/O2 gas mixture containing different concentrations of oxygen are revealed. The composition and generation rules of decomposition products of the gas mixture under the faults are obtained, and the correlation between the types and contents of characteristic decomposition products and the fault types, as well as the regulation of oxygen to C5F10O gas mixture decomposition products and the inhibition mechanism of solid product precipitation are analyzed. In conclusion, based on the simulation and experimental results, we proposed the stability optimization scheme of silver-plated protective layer on copper surface for metal copper material with poor gas-solid stability of C5F10O/N2/O2 gas. We extracted the characteristic products characterizing the discharge and thermal fault of C5F10O/N2/O2 gas mixture, which provided a reference for the on-line fault monitoring based on the decomposition components. We tested the biosafety of C5F10O and its arc decomposition products, and evaluated its application safety based on the discharge and thermal fault decomposition characteristics of C5F10O/N2/O2 gas mixture, and proposed targeted safety protection measures and suggestions
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Lamotte, Jean. "Etude par spectroscopie infrarouge des proprietes superficielles de la thorine et des especes adsorbees resultant de l'interaction co + h : :(2)". Caen, 1987. http://www.theses.fr/1987CAEN2047.
Capitoli di libri sul tema "Gas-Solid interface stability":
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Mohapatra, Lagnamayee, e Jun Ha Park. "A Triphasic Superwetting Catalyst for Photocatalytic Wastewater Treatment". In Photocatalysts - New Perspectives [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.109509.
Abstract (sommario):
The increasing organic contamination is mainly produced by the widespread industrial, agricultural, and household applications and has become a serious worldwide issue. Therefore, we need to develop sustainable and environmentally friendly technologies to reduce waste detrimental to the environment. A promising approach is known as heterogeneous photocatalysis, inspired by natural photosynthesis. For this purpose, the challenges raised to synthesize appropriate surface nano/microstructured materials with long-term stability and mechanical durability for practical use. The traditional photocatalytic system is diphasic (dependent upon the solid-liquid phase), where the solid-liquid reaction interface depends upon the mass transfer. Especially, the low concentrations of oxygen in water and the slow diffusion rate limit the removal of electrons which decreases the photocatalytic reaction rates even if the presence of high light intensities. Therefore, the work aims to develop novel triphasic superwetting photocatalytic materials where the photocatalytic reaction is carried out at gas-liquid-solid joint interfaces. This triphasic contact line can allow oxygen from the air to this reaction interface and minimize electron-hole recombination even at high light intensities. Herein, we intend to discuss the importance of a novel superwetting triphasic nanoarrays catalyst that will be developed and implemented.
Atti di convegni sul tema "Gas-Solid interface stability":
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Sun, Xiaohui, Baojiang Sun e Zhiyuan Wang. "Wellbore Dynamics of Kick Evolution Considering Hydrate Phase Transition on Gas Bubbles Surface During Deepwater Drilling". In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61125.
Abstract (sommario):
It is of high potential and risk to form gas hydrate along the wellbore in deepwater drilled-kick scenarios. Considering the transient mass transfer process that appears as the hydrate shell renewal at gas-liquid interface, we build a fully coupled hydrodynamic-hydrate model to describe the interaction of hydrate phase transition characteristics and wellbore multiphase flow behaviors. Through comparison with experimental data, the performance of proposed model is validated and evaluated. The simulation results show that the hydrate formation region is mainly near the seafloor affected by the fluid temperature and pressure distributions along the wellbore. The volume change and mass transfer over a hydrate coated moving bubble, vary complicatedly, because of the hydrate formation, hydrate decomposition and bubble dissolution (both gas and hydrate). Overall, hydrate phase transition can significantly alter the void fraction and migration velocity of free gas in two aspects: (1) when gas enters the hydrate stability field, a solid hydrate shell will form around the gas bubble, and thereby the velocity and void fraction of free gas can be considerably decreased; (2) the free gas will separate from solid hydrate and expand rapidly near the sea surface (out of hydrate stability field), which can lead to an abrupt hydrostatic pressure loss and explosive development of kick accident. These two phenomena generated by hydrate phase transition can make deepwater gas kick to be “hidden” and “abrupt” successively, and present challenges to early kick detection and wellbore pressure management.
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Li, Zhuoran, Jiahui You e Guan Qin. "Pore-Scale Modellings on the Impacts of Hydrate Distribution Morphology on Gas and Water Transport in Hydrate-Bearing Sediments". In SPE Canadian Energy Technology Conference. SPE, 2022. http://dx.doi.org/10.2118/208983-ms.
Abstract (sommario):
Abstract Gas and water transport behavior, which is controlled by the pore characteristics and capillarity in hydrate-bearing sediments (HBS), is one of the key factors affecting the gas production. Hydrate distribution morphology (HDM) can significantly influence the pore structures of HBS, affecting the relative permeabilities of gas and water. To elucidate the impacts of HDM in microscopic scale, a phase-field lattice Boltzmann (LB) model is developed to describe the gas and water transport in HBS.To simulate the transport of immiscible fluids, which exist obvious density and viscosity contrasts, a phase-field LB model with the conservative form of interface-tracking equation is developed to suppress the spurious currents at phase interfaces. To describe the fluid-solid interactions, the bounce-back condition is applied for both solid phases (hydrate and grains) to achieve the non-slip condition and the wettability condition is applied for grains and hydrate to describe the wettability behavior. To improve the numerical stability, the multi-relaxation-time (MRT) collision operator is applied and the discretization schemes with 8th order accuracy for the gradient operator are selected. In this work, we first validated our model by applying several benchmark cases aiming at fluids with obvious density contrasts such as the layered Couette/Poiseuille flows, Rayleigh–Taylor instability. Then the synthetic geometries of the pore-filling and grain-coating HBS with several hydrate saturation (Shyd) were constructed by guaranteeing the same extent of connectivity. Then the steady-state relative permeability measurement and drainage capillary pressure measurement processes were simulated by the LB model for two HDM cases under several Shyd. The results showed that in the hydrophilic HBS, the relative permeability of gas in the pore-filling case is obviously larger than that in the grain-coating case at the same Shyd, and larger capillary pressure can be obtained in the pore-filling case. In addition, as the Shyd increased, it would notably enhance these differences of fluids relative permeability and capillary pressure between two HDM cases. Because the HDM can not only influence the pore space structures but also the wettability of the porous medium by creating solid surfaces of varying wettability, the distribution and transport of fluid phases in different HDM cases can be obviously affected. The phase-filed LB model applied in this study is capable to handle and suppress the spurious currents at phase interfaces, ensuring a satisfactory numerical stability and accuracy. Thus, the real density and viscosity contrasts between the water and gas under the in-situ thermodynamic conditions can be considered in the simulation. The impacts of HDM on the gas and water transport were quantitively analyzed by simulating multiphase flow processes in HBS.
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Lloyd-Mills, Frank, Jingyi Cheng, Meng Wang e Wenfeng Li. "Geomechanical Characterization of Natural Shale-Sandstone Interface". In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0309.
Abstract (sommario):
ABSTRACT Understanding the strength of rock discontinuities has been one of the core research topics in geomechanics over the past decades. This is unsurprising as many structural failures in underground excavations, including mining and tunnelling, occur at rock discontinuities. In oil, gas, and geothermal industry, the strength of rock discontinuities has also attracted a great deal of attentions because, for example, pre-existing discontinuities can significantly change the structures of hydraulic fracture networks. It is also anticipated that the strength of rock discontinuities will become increasingly important for leakage risk assessment of carbon dioxide geological sequestration projects. For all these reasons, we must achieve a good understanding of strength of natural rock discontinuities at the subsurface stress conditions, which, unfortunately, is not well explored. This problem can be primarily attributed to the limited numbers of valid rock samples that contain natural and undisturbed rock discontinuities, especially for the case of cohesive rock discontinuities. In this study, we obtained some rock specimens with naturally bonded shale-sandstone interface. We measured the geomechanical properties of the natural shale-sandstone interface under constant normal loads, using biaxial direct shear apparatus. The measured strength of interface indicates the combined effect of normal loading levels and natural interface roughness. Our characterization provides valuable geomechanical data of natural shale-sandstone interface at the subsurface conditions. These data can benefit all subsurface engineering projects where it is crucial to examine shale-sandstone interface failure for project success, including underground mining, tunnelling, fluid injection/extraction in sandstone reservoirs of shale caprocks. INTRODUCTION Geomechanical properties of rock discontinuities are of great importance in many underground engineering projects. In mining engineering, rock discontinuities often govern deformation and failure of rock masses surrounding underground openings, such as the occurrence of coal bumps due to lost of constraint at coal-rock interface (Li et al., 2015a and 2015b). In oil and gas engineering, rock discontinuities are the primary fluid flow pathways in tight formations and can also greatly influence the wellbore stability and hydraulic fracture structures (Karatela et al., 2016; Li et al., 2021a and 2021b; Li et al., 2022; Meng et al., 2021a and 2021b; Welch et al., 2021). In enhanced geothermal system (EGS), rock discontinuities govern the hydrofracking and hydroshearing process and contribute significantly to the stimulated rock volume for effective fluid flow and heat mining (Rinaldi and Rutqvist, 2019; Bijay and Ghazanfari, 2021; Meng et al., 2022). In carbon sequestration projects, rock discontinuities can cause CO2 leakage under rock stress or fluid pressure perturbation (Carey et al., 2009; Pan et al., 2013; Frash et al., 2017). In nuclear waste disposal or underground nuclear explosion detection, rock discontinuities can facilitate transport of the radionuclide gas isotopes from the cavity to the surface (Zhang et al., 2022). It is anticipated that in carbon mineralization projects, rock discontinuities can greatly affect project success because mineral dissolution and solid mineral molar precipitation can either promote or kill the long-term fracture permeability due to the coupled thermos-hydro-mechanical-chemical (THMC) processes (xiong et al., 2017; Menefee et al., 2018). For all those reasons, it is imperative to study the geomechanical properties of rock discontinuities for effective utilization of subsurface resources.
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Segal, Corin, Maxx J. Friedauer, Holavanahalli S. Udaykumar e Wei Shyy. "Combustion Characteristics of High-Energy/High-Density Hydrocarbon Compounds". In ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-0197.
Abstract (sommario):
Abstract The combustion characteristics of PCU Alkene Dimers (C22H24) are evaluated as solid fuels in high speed flows, at conditions typical for ramjet operation (i.e., Mach 0.25, stagnation temperature and pressure of 300 K and 150 kPa, respectively). Samples of the dimer are binded into a solid layer with a styrene-polybutadiene copolymer (8% w/w) on the test chamber wall and convectively ignited by a gaseous flame in air. The goals of this research are of both practical and fundamental relevance: (i) determine the ability of the high energy fuel to increase practical devices’ performance, (ii) quantify and improve the combustion characteristics of the alkene dimers (i.e., ignition, flame stability, particulate formation), (iii) investigate the dynamics of the solid-gas interface combustion. To date, ignition times and rates of heat release were measured and the theoretical modelling was initiated. Preliminary results indicate that, in the present configuration, the dimer ignition times fall within the range reported in literature for other solid fuels. Large differences exist among different sets of data due primarily to nonsimilar geometrical configuration of the test. The dimer exhibits substantial rates of heat release in comparison with other solid fuels.
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Fameau, Anne-Laure. "Edible oleofoams stabilized by fatty acid and fatty alcohol crystalline particles". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/isqv7867.
Abstract (sommario):
Liquid foams are colloidal systems based on gas bubbles dispersed in a liquid continuous phase. Two different categories of foams exist: aqueous or non-aqueous. In contrary to aqueous foams, which have been extensively studied, non-aqueous foams represent a new promising emerging field, especially for edible applications [1]. Oleofoams based on edible oils are more difficult to obtain in comparison to aqueous foams due to the lower surface-activity of most edible emulsifiers at the oil-air interface in comparison to air-water interface [2]. Nevertheless, the fundamental research in this area is tremendously growing, and the industrial potential of oleofoams is high as novel structuring materials to substitute solid fats [3-4]. Oleofoams could be used to create food products with reduced fat content in combination with new textures and sensorial properties [4]. This talk aims to describe the state of the art on oleofoams and where do the scientific community stand for the understanding of the stabilization mechanisms by showing examples of oil foams based on fatty acids and fatty alcohol systems [2]. We recently have shown that the weight ratio (R) between fatty acids and fatty alcohols tuned both the oleogels and the oil foam properties [2]. Two optimal R, for which mixed crystals are present, produce the best foams in terms of overrun, foam firmness and foam stability. R not only affects the crystal size, but also the number of crystalline particles present in the oleogel. We highlighted that there is a link between the oleogel stability and hardness with their resulting oleofoam properties [2].[1] Fameau, A.-L. and A. Saint-Jalmes, Front. Sustain. Food Syst., 2020.;[2] Callau, M., et al., Food Chem. 333: 127403, 2020.[3] Fameau, A.-L. and A. Saint-Jalmes, Adv. Colloid Interface Sci. 247: 454–464, 2017.;[4] Fameau, A.-L..Handbook of Molecular Gastronomy. CRC Press, 2021. 357-364.
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Lo¨ffler, Karsten, Hongyi Yu, Tatiana Gambaryan-Roisman e Peter Stephan. "Flow Patterns and Heat Transfer in Thin Liquid Films on Walls With Straight, Meandering and Zigzag Mini-Grooves". In ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62318.
Abstract (sommario):
Thin liquid films flowing along solid walls are widely used in technological applications in which high rates of heat and mass transport are required. The transport processes can be further intensified by using structured walls. In the present work hydrodynamics and heat transfer in falling liquid films on heated vertical and inclined walls with mini-grooves are studied experimentally and theoretically/numerically. The experiments are performed with straight, meandering and zigzag mini-grooves. The film dynamics is investigated using a confocal chromatic sensoring (CHR) technique. The flow patterns and the temperature of the liquid-gas interface are visualized using the high-speed infrared thermography. The wall temperature distribution is measured with thermocouples. A numerical model for description of the velocity and temperature fields in the thermal entrance region of the falling films on smooth and structured walls is developed. This model is based on the solution of the Graetz-Nusselt problem for falling films on grooved plates. We show that the mini-grooves significantly affect the flow patterns, film stability and heat transfer in falling liquid films. Using grooved walls leads to the increase of the maximal attainable heat transfer rate.
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Hohloch, Martina, Andreas Huber e Manfred Aigner. "Experimental Investigation of a SOFC/MGT Hybrid Power Plant Test Rig: Impact and Characterization of Coupling Elements". In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25918.
Abstract (sommario):
The main topic of the paper is the discussion of the operational behavior of the solid oxide fuel cell (SOFC)/micro gas turbine (MGT) hybrid power plant test rig with the pressure vessels of the SOFC emulator. In the first part a brief introduction to the test rig and its components is given. In the arrangement of the test rig the MGT is connected via an interface to the tubing system. Here, the preheated air after the recuperator can be led either to the emulator or via a bypass tube directly to the MGT. Furthermore, there is a direct connection between the compressor outlet and emulator for the startup and shutdown procedure. The facility is equipped with detailed instrumentation, including mass flow meters, thermocouples and pressure probes. In the second part of the paper the characterization of the hybrid power plant test rig is shown. To analyze the thermodynamic and fluid dynamic impact of the coupling elements various studies were carried out. Hereby, the influence of the coupling elements on the operational behavior, system stability and system performance of the micro gas turbine is shown for stationary load points, as well as during transient maneuvers like startup, load-change and shutdown. To avoid critical operating conditions limitations were defined and emergency maneuvers were developed and tested. Out of these investigations an operating concept for the hybrid power plant test rig can be derived.
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Chen, Yuchuan, Bohui Shi, Wenping Lan, Fangfei Huang, Shunkang Fu, Haiyuan Yao e Jing Gong. "Study on Hydrate Formation and Dissociation in the Presence of Fine-Grain Sand". In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93200.
Abstract (sommario):
Abstract During the solid fluidization exploitation of shallow non-diagenetic NGHs (Natural Gas Hydrates) in the deep-water, hydrates together with mineral sand, natural gas, seawater and drilling fluids flow in the production pipeline. Natural gas released from hydrates during the process of solid fluidization will reform hydrates under the suitable conditions. Therefore, research on the formation and dissociation of methane hydrates in the presence of fine-grain sands is of great significance for ensuring the flow assurance of solid fluidization exploitation of shallow non-diagenetic NGHs in the deep-water field. In this paper, a high-pressure autoclave was used to carry out the experiments of hydrate formation and dissociation under different initial pressures and particle sizes of the fine-grain sand, for investigating into the hydrate induction time, formation amount, rate and dissociation affected by the presence of the fine-grain sand. Results indicated that hydrate formation kinetics in the presence of fine-grain sand was supposed to be also affected by mass/heat transfer, thermodynamics and kinetics. The fine-grain sand would be dispersed in the water phase under the effect of buoyancy, gravity and shearing force. Besides, the fine-grain sand at the gas-water interface would hinder the mass transfer of the methane gas into the water, inhibiting the nucleation of the hydrates, which was more obviously at the lower pressure. When the driving force for hydrate formation was larger, hydrate formation amount increased with the decrease of the particle size of the fine-grain sand. However, hydrate formation amount decreased with the decrease of the particle size of the fine-grain sand when the driving force for hydrate formation was lower. The average growth rate in the presence of fine-grain sand with 2.9 μm was larger than that of 9.9 μm. However, hydrates grew rapidly and subsequently tended to grow at a lower rate in the presence of fine-grain sand with 2.9 μm at 8.0 MPa initial pressure, which was assumed to be affected by the unconverted water wrapped inside the hydrate shell. The changing trends of gas emission during the dissociation process between the sand-containing system and the pure water system were nearly the same. The amount of gas emission reached a peak value within 15 minutes and then tended to stabilize. The difference in the amount of gas emission mainly depended on the formation amount before hydrate dissociation. Hydrates grew rapidly once methane hydrates nucleated in the presence of the fine-grain sand at the lower pressure, which would increase the plugging risk during the process of the solid fluidization exploitation. Further study of the fine-grain sand on flow assurance during hydrate dissociation process should be done in the future. The results of this paper provided an important theoretical basis and technical support for reducing the risk in the process of the solid fluidization exploitation of shallow non-diagenetic NGHs in the deep-water field.
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Mahmoud, Ali Adel, Ala Shafeq AL-Dogail, Rahul Narayanrao Gajbhiye e Abdullah Saad AlSultan. "Development of Emulsified Acid System using Organoclays". In Gas & Oil Technology Showcase and Conference. SPE, 2023. http://dx.doi.org/10.2118/214149-ms.
Abstract (sommario):
Abstract Matrix acidizing technique is used to enhance the production of hydrocarbons from a reservoir, especially in low permeable reservoirs and in the case of formation damage. In carbonate reservoirs, acid stimulation jobs are challenging due to the acid's strong reactivity with the formation. Thus, the ability to create wormholes will be limited. Wormholes allow hydrocarbons to be produced by flowing into the wellbore. Emulsified acids system helps to overcome this challenge by reducing face dissolution. Recently, Pickering emulsions have attracted attention due to their easy preparation and enhanced stability features. In Pickering emulsions, solid microparticles that localize at the interface between liquids are used as stabilizers instead of surfactants. The preparation of emulsified acid system (EAS) is a complex process sensitive to several parameters governing the properties/feature of the emulsified system. The parameter includes mixing the aqueous and oleic phase, the rotational speed, the time of mixing, and the quantity of emulsifying agent (organology). It requires performing several experiments to identify the proper procedure and optimum range of the parameters affecting the emulsified acid preparation of desired properties. In this study, several experiments were performed using three types of organoclays (OC) namely Claytone-SF (strong), Claytone-EM (medium), and Laponite-EP (weak). Thermal stability tests were carried out at room temperature, 80ºC, and 120ºC. Rheology tests were performed for the most stable emulsions. This study investigated the potential of using special nanoparticles as emulsion stabilizers instead of surfactants. A proper sequence of the component mixing and optimum range of the factors affecting the emulsion preparation and properties were identified. This work aims to study the parameters involved in the emulsified acid preparation and optimize them to obtain a stable EAS.