Download or read book Flow and Mixing Optimization of an Existing Biogas Plant through CFD Simulation and Velocity Measurements Prepared written by Obada Yaghi and published by GRIN Verlag. This book was released on 2019-04-17 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bachelor Thesis from the year 2016 in the subject Engineering - Mechanical Engineering, grade: 94%, German Jordanian University (hosted by Hamburg University of Technology), language: English, abstract: This research project enables further development and improvement of the mixing efficiency in an existing biogas plant, by utilizing CFD simulation as well as a newly developed flow sensor in addition to supportive laboratory tests. The flow was analyzed considering the following variables: The mixing time, the Dry Matter (DM) content, the positioning of the agitators and how it can be related to the amount of velocity dead-zones. The velocity measurements took place at the biogas plant of the company Ardestorfer Bioenergie GmbH in the district of Buxtehude. The current plant capacity is approximately 1.6 MWel using animals manure, energy crops as well as agricultural residuals. In order to be able to perform the CFD simulation, a complete 3D model had to be done of the examined fermenter and the mixing agitators. Moreover, the current setup including fluid properties, boundary and initial conditions had to be taken into consideration. Velocity measurements were used as a validation approach for the simulation results, furthermore to acquire an overview of the flow behavior over the investigated mixing period. Firstly, it was found that at higher DM content the flow seemed to be more stable, and the velocity values get quite higher at the examined points. Moreover, at higher DM content (9.35% compared with 8.8%) the velocity dead-zones seemed to be approximately 70% less. Secondly, another approach was considered to improve the mixing and to minimize the dead-zones by changing the position of the main agitator. The new scenario showed fewer dead-zones by approximately 65% according to the CFD model. Thirdly, at all scenarios and setups, the flow seemed to reach the maximum possible velocity, and rather motion distribution after 150-180 seconds. Showing no remarkable improvement after this period. The mentioned findings were concluded based on comparisons between different velocity measurements as well as CFD simulation results at different operating conditions and setups. Being able to offer proper recommendations for a better energy efficiency in terms of lower energy consumption and better mixing all over the fermenter.

Download or read book Computational Fluid Dynamics CFD Simulation of a Gas Solid Fluidized Bed Residence Time Validation Study written by Baru Debtera and published by GRIN Verlag. This book was released on 2021-11-29 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Academic Paper from the year 2021 in the subject Physics - Mechanics, , language: English, abstract: In this study, numerical simulations of a gas-solid fluidized bed reactor involving a two-fluid Eulerian multiphase model and incorporating the Kinetic Theory of Granular Flow (KTGF) for the solids phase have been performed using a commercial Computational Fluid Dynamics (CFD) software. The fluidized bed setup consists of 1,5 m height and 0,2 m diameter in which a series of experiments were performed using Helium tracer to determine the Residence Time Distribution (RTD) at various normalized velocities i.e., with different degrees of gas-solids mixing. Both 2D and 3D simulations of the fluidized bed reactor are performed. The main purpose of this study is to understand the hydrodynamic behavior of a gas-solid fluidized bed reactor through a framework of Eulerian multiphase model and to analyze hydrodynamic behavior of the gas-solids mixing.

Download or read book Gas Liquid Flow Modeling for Renewable Fuels Production written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerobic/anaerobic and gas fermentation pathways have emerged as promising new technologies for the generation of renewable fuels/chemicals from biomass derived sugars, and mixtures of greenhouse/energy rich gas streams (CO2/CH4/H2/CO) via microbial action. Example pathways include sugars-to-ethanol conversion, biomethanation (CO2/H2 to CH4), biogas upgrading, CO fermentation and wet-waste conversion. Gas and liquid phase transport, mass-transfer, and mixing physics at large length scales can significantly affect microbial conversion rates, particularly when the microbial reaction requires a narrow set of conditions. These phenomena are difficult to study in small-scale bench-top reactors that are typically well-mixed. Predictive computational fluid dynamics (CFD) based simulations can therefore aid in the scale-up, design and optimization of these reactors. This work presents multiphase Euler-Euler CFD simulations of at-scale (~500 m3) bioreactors. Our mathematical model treats the gas and liquid as interpenetrating phases. This approach reduces the computational complexity of tracking individual gas bubbles that are several orders of magnitude smaller than reactor dimensions. We solve the Reynolds averaged Navier-Stokes (RANS) multiphase equations that account for phase and chemical species transport, interphase mass and momentum transfer and uses a phenomenological model for gas uptake by microbes. We use a customized solver derived from open-source CFD toolbox, OpenFOAM [1], to perform these simulations, which has been validated against small-scale reactors in our previous work [2]. There is currently a knowledge-gap regarding bubble-size distributions when using gas mixtures with vastly different properties, which can have a significant impact overall mass-transfer. For example, hydrogen bubbles are more buoyant compared to other relatively heavier gases (CO2/CH4/CO), resulting in a large distribution of residence times and bubble sizes. This work therefore develops a deeper understanding of bubble dynamics and interphase mass transfer in such heterogenous gas mixtures through well-resolved computational models. We use a population balance model (PBM) for bubble-size-distribution modeling that is validated against small-scale experiments in our solver with an uncertainty quantification study for bubble coalescence and break-up model parameters. Results pertaining to multiple simulations of gas-fermentation reactors are presented where gas mixtures with varying compositions of CO2/CH4/CO/H2 are imposed at the sparger boundaries. The spatio-temporal variations in bubble-size distribution and mass transfer coefficient are analyzed for varying superficial velocities and gas-compositions for varying sizes of bubble-column and airlift reactors. This work will also examine the performance of different reactor designs, viz. bubble column reactor, airlift reactor with an internal draft tube, and a stirred-tank reactor with Rushton impellers. Reactor mass-transfer coefficient, gas hold-up, and dissolved gas distribution are critically analyzed among reactors, and sensitivity studies pertaining to gas flow rates and reactor geometry will be presented. [1] Weller, H., Tabor, G., Jasak, H. and Fureby, C., A tensorial approach to computational continuum mechanics using object-oriented techniques, Computers in physics, 12, 6, 620--631, 1998. [2] Rahimi, M., Sitaraman, H., Humbird, D. and Stickel, J., Computational fluid dynamics study of full-scale aerobic bioreactors: Evaluation of gas-liquid mass transfer, oxygen uptake, and dynamic oxygen distribution, Chemical Engineering Research and Design, 139: 283-295.

Download or read book Computational Fluid Dynamics CFD Simulation of Flow in Mixing Reactor written by Wain Ket Chong and published by . This book was released on 2016 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixing reactor is a common unit operation in many industrial processes. It is often encountered multiphase flow for mixing process. A computational fluid dynamics (CFD) model based on the mixture formulation for multiphase flow was created to study the mixing hydrodynamics of oil and water in a mixing reactor. This project aimed to develop a reliable CFD model that was able to predict the hydrodynamic properties like velocity or volume fraction. A grid dependency study was conducted to determine the effect of coarse, medium and fine meshes. The simulations were based on an experimental study where the mixing of oil and water occurred in the external loop. It had shown that the medium mesh was seem satisfactory to fulfill the evaluation criterion. The error between prediction of CFD model and experimental data was also within the tolerant range.

Download or read book CFD Simulations in Mechanically Stirred Tank and Flow Field Analysis written by Hélène Caillet and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anaerobic digestion is a widely used process for waste treatment and energy production. This natural process takes place in a controlled environment, anaerobic digesters. Mixing is one of the main operating parameters. The understanding of the flows during the agitation of the medium is crucial for the optimization of the process yield. In fact, the mass and heat transfers are enhanced by the agitation. However, the complex biochemical reactions can be inhibited with overly vigorous agitation. A detailed and in-depth understanding of the phenomena occurring during agitation requires modeling studies. In this chapter, we propose a general approach, based on computational fluid mechanics (CFD), to analyze the mechanical mixing of an anaerobic reactor. We apply this work to the anaerobic digestion of the sugarcane vinasse, which is a liquid waste generated during the production of alcohol. The single-phase Reynolds-averaged Navier-Stokes (RANS) simulations of mechanical agitation of Newtonian fluids for different rotational speeds are presented. The equations system is closed with the standard k-epsilon turbulence model. The flow field is analyzed with the velocity profiles, the Q and Lambda2 fields, the pressure and the vorticity.

Download or read book Computational Fluid Dynamics for Engineers written by Bengt Andersson and published by Cambridge University Press. This book was released on 2011-12-22 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational fluid dynamics, CFD, has become an indispensable tool for many engineers. This book gives an introduction to CFD simulations of turbulence, mixing, reaction, combustion and multiphase flows. The emphasis on understanding the physics of these flows helps the engineer to select appropriate models to obtain reliable simulations. Besides presenting the equations involved, the basics and limitations of the models are explained and discussed. The book combined with tutorials, project and power-point lecture notes (all available for download) forms a complete course. The reader is given hands-on experience of drawing, meshing and simulation. The tutorials cover flow and reactions inside a porous catalyst, combustion in turbulent non-premixed flow, and multiphase simulation of evaporation spray respectively. The project deals with design of an industrial-scale selective catalytic reduction process and allows the reader to explore various design improvements and apply best practice guidelines in the CFD simulations.

Download or read book CFD Simulation and Verification of Flow in Mixing Tanks written by Fengliang Huang and published by . This book was released on 1997 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CFD Simulation of Turbulent Non Newtonian Slurry Flows in Horizontal Pipelines written by Mohsen Sadeghi and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complex concentrated slurry flows in horizontal pipelines are widely seen in many industries for transportation of solid particles or process wastes. i.e., tailings. Slurry flows can occur in a turbulent regime, and the carrier fluid usually shows a non-Newtonian behavior. Understanding the flow behavior of slurries and the ability to predict the changes in the behavior with respect to variations in the flow conditions are of great importance and help the operators in pipeline design and optimization, and possibly development of separation processes. CFD simulation is a powerful tool to study the multiphase slurry systems, and can be applied to a wide variaty of configurations, flow conditions, and number of phases. In this work, CFD models were developed using ANSYS® FLUENT 2020 R2 commercial package to investigate the flow behavior of slurries in laboratory and industrial scale pipelines. The first part of this thesis investigates a model system in a lab-scale pipeline by studying the transport of monodisperse and bimodal particles in a turbulent non- Newtonian carrier using an Eulerian-Eulerian CFD model coupled with granular kinetic theory. The CFD predictions agreed satisfactorily with experimental data of solids concentration and pressure drop reported in the literature. The effects of the diameter of monodispersed particles (0.5-2 mm), solids concentration (0.1- 0.4), mixture velocity (3-6 m/s), and carrier fluid density (1000-1400 kg/m3) on flow behavior and specific energy consumption were investigated. The mixture velocity has the most significant effect on pressure drop and radial solids distribution. An increase in mixture velocity or solids concentration led to a larger pressure drop, primarily due to the intensified particle-wall and particle-particle interactions. At the maximum velocity of 6 m/s, the solids concentration distribution reversed near the pipe invert with a local maximum in turbulent kinetic energy from a low solids concentration, while turbulence was dampened at the pipe core where the solids concentration is higher. A higher solids concentration and lower mixture velocity led to lower specific energy consumption. In the second part, the work was extended to an industrial-scale pipeline with the study of transport of three-phase oil sands tailings in a horizontal pipeline using the CFD technique via the mixture multiphase model coupled with the kinetic theory of granular flow. The solid particles and bitumen droplets are conveyed via a non-Newtonian carrier fluid in a turbulent regime inside an industrial-scale pipeline with 74 cm diameter and 220m length. Ten sets of field data of velocity distribution and pressure drop were collected and used for the validation of the model. Overall, the CFD results showed exceptional agreement with the field data, with errors of

Download or read book Simulation Optimization and Instrumentation of Agricultural Biogas Plants written by Christian Wolf and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multi fidelity modeling and optimization of biogas plants written by Martin Zaefferer and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Fluid Dynamics written by Adela Ionescu and published by BoD – Books on Demand. This book was released on 2018-02-14 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the result of a careful selection of contributors in the field of CFD. It is divided into three sections according to the purpose and approaches used in the development of the contributions. The first section describes the "high-performance computing" (HPC) tools and their impact on CFD modeling. The second section is dedicated to "CFD models for local and large-scale industrial phenomena." Two types of approaches are basically contained here: one concerns the adaptation from global to local scale, - e.g., the applications of CFD to study the climate changes and the adaptations to local scale. The second approach, very challenging, is the multiscale analysis. The third section is devoted to "CFD in numerical modeling approach for experimental cases." Its chapters emphasize on the numerical approach of the mathematical models associated to few experimental (industrial) cases. Here, the impact and the importance of the mathematical modeling in CFD are focused on. It is expected that the collection of these chapters will enrich the state of the art in the CFD domain and its applications in a lot of fields. This collection proves that CFD is a highly interdisciplinary research area, which lies at the interface of physics, engineering, applied mathematics, and computer science.

Download or read book Biogas from Waste and Renewable Resources written by Dieter Deublein and published by John Wiley & Sons. This book was released on 2008-04-18 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written as a practical introduction to biogas plant design and operation, this book fills a huge gap by presenting a systematic guide to this emerging technology -- information otherwise only available in poorly intelligible reports by US governmental and other official agencies. The author draws on teaching material from a university course as well as a wide variety of industrial biogas projects he has been involved with, thus combining didactical skill with real-life examples. Alongside biological and technical aspects of biogas generation, this timely work also looks at safety and legal aspects as well as environmental considerations.

Download or read book Nordic heating and cooling written by Patronen, Jenni and published by Nordic Council of Ministers. This book was released on 2017-05-29 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: According to the EU Commission, the heating and cooling sector must sharply reduce its energy consumption and cut its use of fossil fuel in order to meet the EU's climate and energy goals. In the Nordic countries, a lot of effort has already been put to make heat production and consumption energy efficient and to decrease the emissions. To disseminate these experiences and good practices wider in Europe, and to identify further needs for co-operation, this study attempts to identify the common approaches of the Nordic countries towards the EU’s heating and cooling strategy and Winter Package regulation. This report describes the results of the work based on Pöyry’s analysis of the current heating and cooling sector practices and regulation in the Nordic countries, and interviews of the regulators and energy industry representatives from each country.

Download or read book Reactor and Process Design in Sustainable Energy Technology written by Fan Shi and published by Elsevier. This book was released on 2014-07-28 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reactor Process Design in Sustainable Energy Technology compiles and explains current developments in reactor and process design in sustainable energy technologies, including optimization and scale-up methodologies and numerical methods. Sustainable energy technologies that require more efficient means of converting and utilizing energy can help provide for burgeoning global energy demand while reducing anthropogenic carbon dioxide emissions associated with energy production. The book, contributed by an international team of academic and industry experts in the field, brings numerous reactor design cases to readers based on their valuable experience from lab R&D scale to industry levels. It is the first to emphasize reactor engineering in sustainable energy technology discussing design. It provides comprehensive tools and information to help engineers and energy professionals learn, design, and specify chemical reactors and processes confidently. Emphasis on reactor engineering in sustainable energy technology Up-to-date overview of the latest reaction engineering techniques in sustainable energy topics Expert accounts of reactor types, processing, and optimization Figures and tables designed to comprehensively present concepts and proceduresHundreds of citations drawing on many most recent and previously published works on the subject

Download or read book Chemical Reactor Modeling written by Hugo A. Jakobsen and published by Springer Science & Business Media. This book was released on 2014-04-02 with total page 1589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics. The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling and in a post graduate course in modern reactor modeling at the Norwegian University of Science and Technology, Department of Chemical Engineering, Trondheim, Norway. The objective of the book is to present the fundamentals of the single-fluid and multi-fluid models for the analysis of single and multiphase reactive flows in chemical reactors with a chemical reactor engineering rather than mathematical bias. Organized into 13 chapters, it combines theoretical aspects and practical applications and covers some of the recent research in several areas of chemical reactor engineering. This book contains a survey of the modern literature in the field of chemical reactor modeling.

Download or read book Process Intensification written by David Reay and published by Butterworth-Heinemann. This book was released on 2013-06-05 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Process Intensification: Engineering for Efficiency, Sustainability and Flexibility is the first book to provide a practical working guide to understanding process intensification (PI) and developing successful PI solutions and applications in chemical process, civil, environmental, energy, pharmaceutical, biological, and biochemical systems. Process intensification is a chemical and process design approach that leads to substantially smaller, cleaner, safer, and more energy efficient process technology. It improves process flexibility, product quality, speed to market and inherent safety, with a reduced environmental footprint. This book represents a valuable resource for engineers working with leading-edge process technologies, and those involved research and development of chemical, process, environmental, pharmaceutical, and bioscience systems. No other reference covers both the technology and application of PI, addressing fundamentals, industry applications, and including a development and implementation guide Covers hot and high growth topics, including emission prevention, sustainable design, and pinch analysis World-class authors: Colin Ramshaw pioneered PI at ICI and is widely credited as the father of the technology

Download or read book Aeration Mixing and Energy written by Diego Rosso and published by IWA Publishing. This book was released on 2018-12-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aeration, Mixing, and Energy: Bubbles and Sparks is the first book on bubbles and sparks, presenting the state-of-the-art on aeration and mixing technology for water and wastewater treatment systems. Aeration and mixing are the heart of wastewater treatment and must be performed well and at high efficiency for successful treatment. After reviewing the most current aeration systems, this book presents the best ways of measuring aeration system performance and to use those measurements for design, control, and sustainable operations. A team of experts in the field were assembled to help write this book, which is the product of several years of work and decades of combined experience. Aeration, Mixing, and Energy: Bubbles and Sparks is a valuable complement to any book on water reclamation and wastewater treatment.