Reactive Transport Modeling Approach and Its Initial Saltcake Dilution Chemical Modeling PDF Download
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Author: Yasuo Onishi
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
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Book Description
Author: Yasuo Onishi
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
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Book Description
Author: Lazaro J. Perez Fonseca
Publisher:
ISBN:
Category :
Languages : en
Pages : 116
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Book Description
Reactive transport modeling is an important tool for the analysis of coupled physical, chemical, and biological processes in Earth systems. Observed reactive transport in heterogeneous porous media shows a different behavior than the established transport laws for homogeneous media. Natural aquifers exhibit physical and chemical heterogeneities at all scales, which leads to reaction and transport dynamics that cannot be explained by traditional reactive models based on the advection-dispersion-reaction equation (ADRE). In particular, the discrepancy is traced back to the nonuniform nature of flow velocity fields, complex spatial concentration distributions, and the degree of mixing between reactants. The role and contribution of these factors is key to provide accurate predictions of reactions. The complexity of the task lies in the enormous range of spatial and temporal scales that reactants find in natural porous media. Hence, the complete characterization of the fate of chemical reactions requires that models accounts for the basic mechanisms that govern the mixing and reaction dynamics. In this thesis, we present a novel methodology for the simulation of homogeneous chemical reactions. The proposed methodology is a random walk particle tracking approach (RWPT) coupled with reactions that simulates bimolecular chemical reactions, and is equivalent to the ADRE. Reactions among particles are determined by a reaction probability given in terms of the reaction rate coefficient, the total number of particles, and an interaction radius that describes a well-mixed support volume at which all particles have the same probability to react. The method is meshless and free of numerical dispersion. The RWPT approach is validated against analytical solutions for different flow scenarios under slow and fast reaction kinetics. We focus on the impact of the mixing degree between chemical species and its role in the global reaction behavior. We first consider a reactive displacement in a Poiseuille flow through a pore channel, this system allow us to quantify the impact of the interaction of interface deformation and diffusion on mixing and reactive transport. We observe overestimation of the global reaction efficiency by the use of the Taylor dispersion coefficient at preasymptotic times, when the system is characterized by incomplete mixing. Next, we observe features of incomplete mixing in a synthetic porous medium. Results show that macroscopic predictions using the hydrodynamic dispersion coefficient overestimates the amount of reaction. In addition, we analize the bimolecular reactive transport in a laboratory experiment, where we find that the amount of reaction is affected by the amount of mixing due to difusion, the amount of mixing due to spreading and the degree of heterogeneity of the flow field. The contributions of these factors induces that ADRE estimation of the total reaction product fails. In order to characterize incomplete mixing and provide an explicit relation between fluid deformation and its impact on the temporal evolution of the chemical reactivity, we develop the dispersive lamella approach based on the concept of effective dispersion which accurately predicts the full evolution of the product mass. Specifically, the approach captures the impact of interface deformation and diffusive coalescence. Using this methodology, we quantify the impact of flow heterogeneities on the amount of fluid mixing in a pore channel, where we observe three temporal regimes based on the production rate of the product mass. In addition, the dispersive lamella predictions capture the kinetics of the reaction in a synthetic porous medium. Results reveal that reaction behavior is controlled by the interface front between the two reactants. In the pore-scale experimental visualization, the dispersive lamella show that reaction is controlled by the deformed mixing interface at early times, and for fingering coalescence at late times.
Author: Deviyani Gurung
Publisher:
ISBN:
Category : Chemical reactions
Languages : en
Pages : 130
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Book Description
Reactive transport modeling is an important tool for the analysis of physical, chemical and biological processes encountered in many environmental systems. Several upscaled models, of natural or engineered porous media, are commonly used for such modeling and take advantage of standard advection dispersion reaction equations (ADREs). These simple models are however unable to account for physical processes that can heavily influence reactive transport in such media, such as pre-asymptotic flow fields and mixing limitations between transport and reaction processes. To account for these complexities, researchers have developed proportionally complex mathematical and simulation-based models. However, these complicated models have remained underutilized among most practitioners owing to their non-intuitive formulations and computationally intensive mathematics. In this thesis, we present a novel, intuitive and relatively less strenuous computational method for the simulation of homogenous chemical reactions through the use of age: defined as exposure-time to the flow field, structured ADREs.The utility of this method is demonstrated through the development of two models to quantify mixing processes and pre-asymptotic dispersion without the use of non-local models. Analysis of reactive transport in porous media has benefited from the concept of mixing ratios, in particular as a basis for mathematical separation of different species and processes. Additionally, general use of solute age has been recently explored as a proxy for reaction extent. Pairing these two concepts we developed mixing ratio models, structured on age, that is cast into a 1D transport formulation and compared with conventional formulations of mixing ratio models. This modeling framework was applied to the problem of mixing-limited reactive transport in one-dimension by explicitly considering unmixed and mixed phases. To address mixing limitations under the entirety of transport, including the pre-asymptotic dispersion timeframe, I use age-dependent dispersion coefficient in a local-formulation of transport. This formulation addresses the divisive controversy surrounding the use of time-dependent dispersion coefficients within an ADRE framework. Our physically intuitive model matches the performance of a recently published complicated and computationally intensive model of transient dispersion in direct comparison. Furthermore, our solutions can be applied to other upscaled one-dimensional transport problems such as river corridor, pipe networks, groundwater flows.
Author: James E Shelby
Publisher: Royal Society of Chemistry
ISBN: 1782625119
Category : Technology & Engineering
Languages : en
Pages : 320
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Book Description
This book provides a concise and inexpensive introduction for an undergraduate course in glass science and technology. The level of the book has deliberately been maintained at the introductory level to avoid confusion of the student by inclusion of more advanced material, and is unique in that its text is limited to the amount suitable for a one term course for students in materials science, ceramics or inorganic chemistry. The contents cover the fundamental topics of importance in glass science and technology, including glass formation, crystallization, phase separation and structure of glasses. Additional chapters discuss the most important properties of glasses, including discussion of physical, optical, electrical, chemical and mechanical properties. A final chapter provides an introduction to a number of methods used to form technical glasses, including glass sheet, bottles, insulation fibre, optical fibres and other common commercial products. In addition, the book contains discussion of the effects of phase separation and crystallization on the properties of glasses, which is neglected in other texts. Although intended primarily as a textbook, Introduction to Glass Science and Technology will also be invaluable to the engineer or scientist who desires more knowledge regarding the formation, properties and production of glass.
Author: Efstathios Michaelides
Publisher: CRC Press
ISBN: 1315354624
Category : Science
Languages : en
Pages : 1559
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Book Description
The Multiphase Flow Handbook, Second Edition is a thoroughly updated and reorganized revision of the late Clayton Crowe’s work, and provides a detailed look at the basic concepts and the wide range of applications in this important area of thermal/fluids engineering. Revised by the new editors, Efstathios E. (Stathis) Michaelides and John D. Schwarzkopf, the new Second Edition begins with two chapters covering fundamental concepts and methods that pertain to all the types and applications of multiphase flow. The remaining chapters cover the applications and engineering systems that are relevant to all the types of multiphase flow and heat transfer. The twenty-one chapters and several sections of the book include the basic science as well as the contemporary engineering and technological applications of multiphase flow in a comprehensive way that is easy to follow and be understood. The editors created a common set of nomenclature that is used throughout the book, allowing readers to easily compare fundamental theory with currently developing concepts and applications. With contributed chapters from sixty-two leading experts around the world, the Multiphase Flow Handbook, Second Edition is an essential reference for all researchers, academics and engineers working with complex thermal and fluid systems.
Author: International Atomic Energy Agency
Publisher:
ISBN:
Category : Business & Economics
Languages : en
Pages : 164
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Book Description
Provides detailed information on the handling, processing and storage techniques most widely used and recommended for waste from non-fuel-cycle activities. The report was designed to meet the needs of developing countries by focusing on the most simple, affordable and reliable techniques and discussing their advantages and limitations.
Author: Donald T. Sawyer
Publisher: Springer Science & Business Media
ISBN: 1489923209
Category : Science
Languages : en
Pages : 310
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Book Description
This monograph consists of manuscripts submitted by invited speakers who participated in the symposium "Industrial Environmental Chemistry: Waste Minimization in Industrial Processes and Remediation of Hazardous Waste," held March 24-26, 1992, at Texas A&M University. This meeting was the tenth annual international symposium sponsored by the Texas A&M Industry-University Cooperative Chemistry Program (IUCCP). The program was developed by an academic-industrial steering committee consisting of the co-chairmen, Professors Donald T. Sawyer and Arthur E. Martell of the Texas A&M University Chemistry Department, and members appointed by the sponsoring companies: Bernie A. Allen, Jr., Dow Chemical USA; Kirk W. Brown, Texas A&M University; Abraham Clearfield, Texas A&M University; Greg Leyes, Monsanto Company; Jay Warner, Hoechst-Celanese Corporation; Paul M. Zakriski, BF Goodrich Company; and Emile A. Schweikert, Texas A&M University (IUCCP Coordinator). The subject of this conference reflects the interest that has developed in academic institutions and industry for technological solutions to environmental contamination by industrial wastes. Progress is most likely with strategies that minimize waste production from industrial processes. Clearly the key to the protection and preservation of the environment will be through R&D that optimizes chemical processes to minimize or eliminate waste streams. Eleven of the papers are directed to waste minimization. An additional ten papers discuss chemical and biological remediation strategies for hazardous wastes that contaminate soils, sludges, and water.
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 784
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Book Description
Author: David G. Lovering
Publisher: Springer
ISBN: 1475717245
Category : Education
Languages : en
Pages : 536
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Book Description
Author: Swapna Mukherjee
Publisher: Springer Science & Business Media
ISBN: 9400766831
Category : Science
Languages : en
Pages : 351
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Book Description
This book is an attempt to provide a comprehensive and coherent description of three widely separated aspects of clays: the science of clays; the industrial uses of clays; and the role of clays in the environment. Most of the existing literature lacks such an integrated study and this work endeavours to fill that gap. An exhaustive account of the science of clays is presented in Part I of the book, which includes the classification, origin and evolution, composition and internal structure, chemical and physical properties of clays; soil mechanics; and analytical techniques for determining clay constituents. Part II provides a comprehensive description of the applications of clays and their derivatives in various industries, while Part III describes the role of clays in the environment; the pollution caused by clay minerals; and the application of clays in order to prevent environmental hazards. A principal feature of the book is its explanation of how the structure and composition of particular clay types facilitate their specific industrial or environmental applications, thus describing the interrelationship between three widely varying aspects of clay. A number of thought-provoking questions are raised at the end of the work in order to leave readers with a better insight in this regard.
