Download or read book Numerical Modeling of Methane Decomposition for Hydrogen Production in a Fluidized Bed Reactor written by Maryam Younessi Sinaki and published by . This book was released on 2014 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: The decomposition of methane for hydrogen production is an attractive alternative to the established method of reforming. This process considerably reduces the emission of greenhouse gases, and its overall efficiency and cost are competitive. The decomposition of methane is performed with a catalyst to produce a substantial amount of hydrogen, and decrease the operating temperature. Between different catalysts available, carbon is selected in this study due to its low rate of decay and advantages such as low cost and availability. Also, a fluidized bed reactor operating in the particulate regime is employed due to the efficient contact between the catalyst and the gas. Consequently, hydrogen production from the thermocatalytic decomposition of methane in a particulate fluidized bed reactor of carbon particles is investigated. To obtain an appropriate design and operation for this process, the effect of different operating parameters and catalyst properties should be investigated on the performance. This aim can be achieved by modeling. A number of models with different complexities have been proposed for this process. Considering the objective of this thesis, a complex kinetic model is required to represent the effect of the catalyst properties. In literature, the kinetics is generally modeled with a global equation using experimental parameters. Since investigation on the effect of the properties of the catalyst is not feasible with this method, the detailed kinetic model with a surface reaction mechanism is employed in this study. Investigation on this surface mechanism is very limited, and only one of the models available in literature is determined to be appropriate. Nevertheless, this model has some important drawbacks. The major problem is that the specific surface area is considered as the only catalyst property affecting the activity of carbon. Experimental studies suggest that the activity of this catalyst is a function of its specific surface area and number of active sites, and neglecting either of these properties can lead to a high inaccuracy. Consequently, a new kinetic model is developed where a modified form of the available mechanism is used, and the number of active sites and the specific surface area of the catalyst are considered in the rate equations. It is noted that although several experimental investigations have been performed on the origin of the active sites, their quantity has not been acceptably determined yet. A method is presented in this study to estimate the number of active sites with the developed model and experimental data. To the best knowledge of the author, this is the first model to incorporate the effect of this parameter for carbon catalysts in the decomposition of methane and quantify its value. Another important problem of the model available in literature is its dependency on experimental measurements for determining the hydrodynamic characteristics of the fluidized bed. In this study, the hydrodynamics of the reactor is modeled with empirical correlations to obtain a complete representation of the process within the required accuracy, with minimal experimental requirements. The model is used to investigate the effect of different operating parameters and catalyst properties on the amount of the initial methane conversion. The operating parameters studied are the temperature, residence time, gas velocity, and composition of the feed gas. The catalyst properties considered are the particle size and pore volume, the number of active sites, and the percentage of fine particles in the bed. The effect of the variations of each of these factors in a certain range is investigated for a fluidized bed reactor operating at the onset of fluidization at nominal condition. The onset of fluidization is maintained by changing the inlet flow rate in a reactor of a specific size. The results show that, considering the range of variations in this study, the procedures that cause the highest improvement in conversion are: increasing the residence time, decreasing the size of particles, adding fine particles to the bed, increasing the temperature, using catalysts with high surface areas or large number of active sites, changing the inlet gas composition, and using catalysts with large pore volumes, respectively. It is noted that all of these improvements are associated with higher initial or operating costs. Therefore, changing each of these factors beyond a certain value is faced with economic and technical barriers. Consequently, the possibility and efficiency of using two factors simultaneously for achieving higher conversions was also investigated. The results can be used as a guideline to choose between several catalysts considering their characteristics, or to suggest appropriate operating conditions.

Download or read book Semi continuous Production of Hydrogen from Catalytic Methane Decomposition Using a Fluidized bed Reactor written by Shankang Ma and published by . This book was released on 2005 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling and Experimental Study of Methane Catalytic Cracking as a Hydrogen Production Technology written by Ashraf Mukhtar Lotfi Amin and published by . This book was released on 2011 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Production of hydrogen is primarily achieved via catalytic steam reforming, partial oxidation, and auto-thermal reforming of natural gas. Although these processes are mature technologies, they are somewhat complex and CO is formed as a by-product, therefore requiring a separation process if a pure or hydrogen-rich stream is needed. As an alternative method, supported metal catalysts can be used to catalytically decompose hydrocarbons to produce hydrogen. The process is known as catalytic cracking of hydrocarbons. Methane, the hydrocarbon containing the highest percentage of hydrogen, can be used in such a process to produce a hydrogen-rich stream. The decomposition of methane occurs on the surface of the active metal to produce hydrogen and filamentous carbon. As a result, only hydrogen is produced as a gaseous product, which eliminates the need of further separation processes to separate CO2 or CO. Nickel is commonly used in research as a catalyst for methane cracking in the 500-700C temperature range. To conduct methane catalytic cracking in a continuous manner, regeneration of the deactivated catalyst is required and circulation of the catalysts between cracking and regeneration cycles must be achieved. Different reactor designs have been successfully used in cyclic operation, such as a set of parallel fixed-bed reactors alternating between cracking and regeneration, but catalyst agglomeration due to carbon deposition may lead to blockage of the reactor and elevated pressure drop through the fixed bed. Also poor heat transfer in the fixed bed may lead to elevated temperature during the regeneration step when carbon is burned in air, which may cause catalyst sintering. A fluidized bed reactor appears as a viable option for methane catalytic cracking, since it would permit cyclic operation by moving the catalyst between a cracker and a regenerator. In addition, there is the possibility of using fine catalyst particles, which improves catalyst effectiveness. The aims of this project were 1) to develop and characterize a suitable nickel-based catalyst and 2) to develop a model for thermal catalytic decomposition of methane in a fluidized bed.

Download or read book Turquoise Hydrogen written by and published by Elsevier. This book was released on 2023-08-23 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turquoise Hydrogen: An Effective Pathway to Decarbonization and Value Added Carbon Materials, Volume 61 in the Advances in Chemical Engineering series, reports on the latest advances in turquoise hydrogen production technologies, including thermo-catalytic, plasma and molten media conversion of natural gas and hydrocarbons streams. Chapters in this new release include Perspective, economic potential and overview of current technologies and challenges, Catalytic and non-catalytic chemical kinetics of hydrocarbons cracking for hydrogen and carbon materials production, Fluid dynamics aspects and reactor scale simulations of chemical reactors, Developments in lab-scale reactors for thermo catalytic production of hydrogen and carbon material, and more. Additional sections cover Product spectra, properties, performances and market applications of carbon materials from hydrocarbons cracking, Molten media pyrolysis technologies for hydrocarbons cracking, Opportunities for turquoise hydrogen production and utilization in the metals and steel industry, and Industrial scale reactors for materials production from hydrocarbons cracking. Includes recent advances in experimental and modeling approaches to turquoise hydrogen and carbon material production in thermal, plasma and molten media pyrolysis Updates on progress in reactor scale modeling, design and testing Provides a comprehensive assessment of techno-economic and sustainability aspects

Download or read book Numerical Simulation of Micro Mini Channel Based Methane Steam Reformer written by Daniel Alan Peterson and published by . This book was released on 2010-06-29 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical modeling of methane-steam reforming is performed in a micro/mini-channel with heat input through catalytic channel walls. The low-Mach number, variable density Navier-Stokes equations together with multicomponent reactions are solved using a parallel numerical framework. Methane-steam reforming is modeled by three reduced-order reactions occurring on the reactor walls. The surface reactions in the presence of a catalyst are modeled as Neumann boundary conditions to the governing equations. Two catalysts are investigated: a porous Nickel substrate and a porous felt with deposited Palladium nanoparticles. The reduced-order mechanism kinetics model is coupled with the flow solver to resolve the chemical species field within the reactor geometry. The effects of the total heat input, heat flux profile, flow rate and inlet steam-methane molar concentration on production of hydrogen are investigated in detail.The results of the parametric study give performance evaluations. An increase of hydrogen production of 10% (molar fraction) is observed when increasing the heat flux from no heat flux to a wall heat flux of 3 kW/m^2. The results from the three heat flux profiles study (constant, linear increasing, and linear decreasing) are increased hydrogen production between the linear decreasing profile (worst performer) and the linear increasing profile (best performer) of 3.5% on a molar basis. Varying flow rate from 800 ml/min to 100 ml/min results in an increase of hydrogen mole fraction of 16%. Hydrogen production is non-linearly related to the steam-methane ratio. Maximum hydrogen production is observed near a ratio of 3.0. The reactions are diffusion limited. The diffusion limitations may be reduced by the introduction of hydrogen extraction or mixing flow.

Download or read book Membrane Reactor Modeling for Hydrogen Production Through Methane Steam Reforming written by Jean-Francois Roux and published by . This book was released on 2011 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A mathematical modeling framework for the methane steam reforming reaction operating in steady state has been developed. Performances are compared between the classic catalytic packed bed reactor and a Pd-based catalytic membrane reactor. Isothermal simulations on MATLAB © has first been conducted and show a higher performance of the membrane reactor over the packed bed reactor. Methane conversion of 1 can be reached for lower temperatures than used with industrial PBR, and better performances are shown for an increase in the operating pressure. Optimum conditions were defined for Temperature (500-600 Celsius), reaction side pressure (16-40 bars), membrane thickness (1-7 micrometers), steam/methane ratio (3-4), reactor length (5-10 meters) and permeate sweep ratio (20 or more). This model was validated by multiple recognized sources. Adiabatic simulations were conducted in order to develop a mathematical model base for non-isothermal simulations. The membrane reactor is again showing a higher conversion of methane compared to the packed bed reactor, however the heat loss due to the membrane and the hydrogen leaving through the tube is decreasing the performances of the MR over the PBR compared to the isothermal case. Results show also that most of the reaction occurs at the very beginning of the reactor.

Download or read book Fluidization Engineering written by D. Kunii and published by Elsevier. This book was released on 2013-10-22 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluidization Engineering, Second Edition, expands on its original scope to encompass these new areas and introduces reactor models specifically for these contacting regimes. Completely revised and updated, it is essentially a new book. Its aim is to distill from the thousands of studies those particular developments that are pertinent for the engineer concerned with predictive methods, for the designer, and for the user and potential user of fluidized beds. Covers the recent advances in the field of fluidization. Presents the studies of developments necessary to the engineers, designers, and users of fluidized beds.

Download or read book Sustainable Hydrogen Production written by Ibrahim Dincer and published by Elsevier. This book was released on 2016-08-05 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sustainable Hydrogen Production provides readers with an introduction to the processes and technologies used in major hydrogen production methods. This book serves as a unique source for information on advanced hydrogen generation systems and applications (including integrated systems, hybrid systems, and multigeneration systems with hydrogen production). Advanced and clean technologies are linked to environmental impact issues, and methods for sustainable development are thoroughly discussed. With Earth’s fast-growing populations, we face the challenge of rapidly rising energy needs. To balance these we must explore more sustainable methods of energy production. Hydrogen is one key sustainable method because of its versatility. It is a constituent of a large palette of essential materials, chemicals, and fuels. It is a source of power and a source of heat. Because of this versatility, the demand for hydrogen is sure to increase as we aim to explore more sustainable methods of energy. Furthermore, Sustainable Hydrogen Production provides methodologies, models, and analysis techniques to help achieve better use of resources, efficiency, cost-effectiveness, and sustainability. The book is intellectually rich and interesting as well as practical. The fundamental methods of hydrogen production are categorized based on type of energy source: electrical, thermal, photonic, and biochemical. Where appropriate, historical context is introduced. Thermodynamic concepts, illustrative examples, and case studies are used to solve concrete power engineering problems. Addresses the fundamentals of hydrogen production using electrical, thermal, photonic, and biochemical energies Presents new models, methods, and parameters for performance assessment Provides historical background where appropriate Outlines key connections between hydrogen production methods and environmental impact/sustainable development Provides illustrative examples, case studies, and study problems within each chapter

Download or read book Advances in Hydrogen Energy written by Catherine E. Grégoire Padró and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Hydrogen has been proposed as the perfect fuel for this future energy system. The availability of a reliable and cost-effective supply, safe and efficient storage, and convenient end use of hydrogen will be essential for a transition to a Hydrogen Economy. Research is being conducted throughout the world for the development of safe, cost-effective hydrogen production, storage, and end-use technologies that support and foster this transition. This book is a collection of important research and analysis papers on hydrogen production, storage, and end-use technologies that were presented at the American Chemical Society National Meeting in New Orleans, Louisiana, USA, in August 1999.

Download or read book Modeling and Design of the Fluidized Bed Reactor for the Oxidative Coupling of Methane written by and published by . This book was released on 2012 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kinetics of Catalytic Reactions written by M. Albert Vannice and published by Springer Science & Business Media. This book was released on 2006-04-09 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes how to conduct kinetic experiments with heterogeneous catalysts, analyze and model the results, and characterize the catalysts Detailed analysis of mass transfer in liquid phase reactions involving porous catalysts. Important to the fine chemicals and pharmaceutical industries so it has appeal to many researchers in both industry and academia (chemical engineering and chemistry departments

Download or read book Circulating Fluidized Bed Reforming Process for Hydrogen Production from Methane written by Pradeep Prasad and published by . This book was released on 2004 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluidized Bed Reactors Processes and Operating Conditions written by John G. Yates and published by Springer. This book was released on 2016-09-27 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.

Download or read book Simulation of Membrane Reactors written by Angelo Bruno Basile and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematics is an effective tool to study and model the world in which we live. Schematically, a model is the representation of a system or a process obtained by substituting to the real phenomenon another one in a more familiar field through simplifications, abstractions and analogies. In this book the authors introduce tools needed to carry out computer simulations of membrane reactors. These simulations serve as a complement to conventional experiments, enabling us to learn something new, something that cannot be found out in other ways. This book emphasises the utility of mathematical modelling as an effective tool for predicting/simulating various membrane reactors processes working under different scenarios. The book is divided in 11 chapters dealing with the approach to different membrane reactors. The separation properties of the membranes are introduced first and used in simple simulations in which no reaction takes place. Afterwards, different approaches for simulation of different membrane reactors (porous, dense, zeolitic, metallic and polymeric, photocatalytic, bio- membrane reactors) are introduced and used is base case studies. Finally, the last chapter briefly introduces new numerical techniques applied to membrane and membrane reactors with particular attention to some aspects of quantum mechanics.

Download or read book Diameter Transformed Fluidized Bed written by Youhao Xu and published by Springer Nature. This book was released on 2020-06-05 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book puts forward the concept of the Diameter-Transformed Fluidized Bed (DTFB): a fluidized bed characterized by the coexistence of multiple flow regimes and reaction zones, achieved by transforming the bed into several sections of different diameters. It reviews fundamental aspects, including computational fluid dynamics simulations and industrial practices in connection with DTFB. In particular, it highlights an example concerning the development of maximizing iso-paraffins (MIP) reactors for regulating complex, fluid catalytic cracking reactions in petroleum refineries. The book is a must-have for understanding how academic and industrial researchers are now collaborating in order to develop novel catalytic processes.

Download or read book 26th European Symposium on Computer Aided Process Engineering written by and published by Elsevier. This book was released on 2016-06-17 with total page 2482 pages. Available in PDF, EPUB and Kindle. Book excerpt: 26th European Symposium on Computer Aided Process Engineering contains the papers presented at the 26th European Society of Computer-Aided Process Engineering (ESCAPE) Event held at Portorož Slovenia, from June 12th to June 15th, 2016. Themes discussed at the conference include Process-product Synthesis, Design and Integration, Modelling, Numerical analysis, Simulation and Optimization, Process Operations and Control and Education in CAPE/PSE. Presents findings and discussions from the 26th European Society of Computer-Aided Process Engineering (ESCAPE) Event

Download or read book Fast Fluidization written by and published by Academic Press. This book was released on 1994-12-23 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decade, circulating fluidization or fast fluidization has developed rapidly, superseding standard bubbling fluidization in many applications; for example, fast fluidization provides a better means forcontrolling emissions from the combustion of high-sulfur fuels and excels when used in boilers in steam plant and power stations. China initiated the study of fast fluidization in the early 1970s. Focusing on the substantial research cultivated in that country, with Kwauk at the leading edge, this latest volume in the Advances in Chemical Engineering Series is written in the context of the international state of the art and addresses some of the most vital issues surrounding this fluidization method."