Download or read book Catalyst Deactivation and Fixed Bed Reactor Modeling written by Rustom M. Billimoria and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling Simulation and Optimization of Industrial Fixed Bed Catalytic Reactors written by S.S.E.H. Elnashaie and published by Routledge. This book was released on 2022-01-26 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades impressive advances have been made toward the understanding and quantitative description of the kinetics. Despite these advances, however, the use of mathematical modelling of gas-solid catalytic reactors in industry is still limited. By consolidating progress in the understanding of catalytic processes, this book applies these fundamental advances to the development of models for design, simulation and optimization of industrial reactors. Paying particular attention to the verification of the developed models against industrial data, these models are used to optimize the performance of many practical reactor cases. Using a systems approach for the development of the different components and the resulting overall models, the book is easy to read and gives an insight into the behaviour of these complex industrial systems. In addition, the practical relevance of bifurcation, instability and chaos to industrial reactors is briefly discussed.

Download or read book CFD Simulation and Experiment of Catalyst Deactivation and Heat Transfer in a Low N Fixed bed Reactor written by Mohsen Behnam and published by . This book was released on 2011 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Modeling of fluid flow, heat transfer and reaction in fixed beds is an essential part of their design. This is especially critical for highly endothermic reactions in low tube-to-particle diameter ratio (N) tubes, such as methane steam reforming (MSR) and alkane dehydrogenation as two important commercial reactions. The modeling of fixed bed reaction is available in literatures with lots of assumptions. However, there is a need for implementing the reaction conditions with diffusion aspects on a real fixed bed reactor without assuming any pseudo conditions. Computational fluid dynamics (CFD) has been found as a suitable tool by many researchers to simulate fixed beds. CFD can simulate complex geometry of randomly-packed tubes, and provides us with more fundamental understanding of the transport and reaction phenomena in reactor tubes. CFD can be used to obtain detailed three-dimensional velocity, species and temperature fields that are needed to improve engineering approaches. Previously, the geometry of 120-degree wall segment (WS) of the whole reactor tube has been studied in our group. Previous works have introduced the coupling of gas flow and resolved species and temperature gradients inside pellets by CFD for methane steam reforming (MSR) and propane dehydrogenation (PDH) without considering deactivation. The deactivation of catalysts due to carbon formation is an important problem in industry, such as steam reforming and the catalytic dehydrogenation of alkanes, which are both strongly endothermic reactions. Many researches were carried out to study the effect of carbon formation and catalyst deactivation on the reactor performance. The local carbon deposition on catalysts can cause particle breakage and strongly decrease reaction rates. Catalyst deactivation in heated tubes removes the heat sink and can result in local hot spots that weaken the reactor tube. This is particularly a problem for a low tube-to-particle diameter ratio fixed bed reactor. A 3D resolved CFD model simulation was used to study the local details of carbon deposition in which the reactions and deactivation take place inside the catalytic solid particles. CFD simulations of flow, heat transfer, diffusion and reaction were carried out using the commercial CFD code FLUENT/ANSYS 6.3 in a 3D 120-degree periodic wall segment with N=4. The mesh used boundary layer prism cells at both the inside and outside particle surfaces and at the tube wall. These reactions were represented in the solid particles using user-defined scalars to mimic species transport and reaction, with user-defined functions supplying reaction rates. Diffusion in the particles was modeled by Fick's law using an effective diffusivity, given by Hite and Jackson's approximation of the Dusty Gas Model. The transient developments of particle internal gradients and carbon accumulation have been studied for the early stages of deactivation. Carbon concentration is initially strongest close to the surface and in the high temperature regions of the catalysts and affected by the wall heat flux. Deactivation of the endothermic reactions causes a slow increase in the average catalyst temperature. The second stage of the research was the verification of our CFD reaction model with experimental data under reacting conditions. The highly endothermic commercial methane steam reforming (MSR) reaction was studied experimentally in a fixed bed reactor. The temperature contributions inside catalyst particles were measured. The MSR reaction showed strong effects on the temperature profile along the reactor. Then, a CFD model was used to predict temperature profiles under MSR reaction conditions. Comparison of CFD and experimental data showed very good qualitative as well as quantitative agreement for temperature inside catalyst particles at different inlet gas temperatures. The last stage was to develop a fundamental energy equation without introducing new adjustable parameters to study heat transfer in fixed beds. In the past, many researchers have been carried out to simulate the heat transfer in fixed bed reactors by using k[subscript r] (effective thermal conductivity) and h[subscript w] (heat transfer coefficient). But the classical model with k[subscript r] and h[subscript w] cannot give a correct T(r) near tube wall, where deactivation is strongest. Therefore we need a better model which can represent the near wall heat transfer more accurate. CFD modeling was used to develop pseudo-continuum model for T(r) using V[subscript r] (r, z) and V[subscript z] (r). To get better temperature at the wall vicinity close to the physical reality. In this model radial thermal conductivity was obtained from Zehner-Schlünder model. The convection heat transfer was calculated in the 2D flow fluid from the CFD run. Results were obtained for Reynolds numbers in the range 240-?1900. The accuracy of the new model has been validated by analytical solution. The temperature calculated by the new velocity field pseudohomogenous energy equation showed reasonable quantitative agreement with values predicted by the CFD model.

Download or read book Fixed Bed Reactor Design and Diagnostics written by Howard F. Rase and published by Butterworth-Heinemann. This book was released on 2013-10-22 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fixed-Bed Reactor Design and Diagnostics: Gas-Phase Reactions presents the essential theoretical and conceptual background of gaseous reactions catalyzed by solid catalysts in fixed beds. This book intends to provide recommendations to professionals who seek for modeling, scale-up, and diagnostics of fixed-bed reactors. The text is divided into three parts. Part I provides the conceptual background and relevant theories. Part II presents recommended mathematical models, scale-up procedures, and diagnostic methods. Part III gives a number of practical examples. The topics that are specifically discussed include heterogeneous catalysis and kinetics; general tubular reactor model; and general diagnostics for fixed-bed reactors. Engineers and professionals working with fixed-bed reactors will find the book highly informative.

Download or read book Adiabatic Fixed Bed Reactors written by Jonathan Worstell and published by Butterworth-Heinemann. This book was released on 2014-08-19 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: Practical Guides in Chemical Engineering are a cluster of short texts that each provides a focused introductory view on a single subject. The full library spans the main topics in the chemical process industries that engineering professionals require a basic understanding of. They are 'pocket publications' that professional engineers can easily carry with them or access electronically while working. Each text is highly practical and applied, and presents first principles for engineers who need to get up to speed in a new area fast. The focused facts provided in each guide will help you converse with experts in the field, attempt your own initial troubleshooting, check calculations, and solve rudimentary problems. Adiabatic Fixed-bed Reactors covers the fundamentals of fixed-bed reactors, including various types and their physical properties. Applications of each device type are discussed, as well as trouble-shooting Solid-supported Catalysts. This text is ideal for any engineer who is new to working with fixed-bed reactors and needs to know the basics quickly and easily. - Practical, short, concise information on the basics will help you get an answer or teach yourself a new topic quickly - Supported by industry examples to help you solve a real world problem - Single subject volumes provide key facts for professionals

Download or read book Multiphase Catalytic Reactors written by Zeynep Ilsen Önsan and published by John Wiley & Sons. This book was released on 2016-07-05 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a holistic approach to multiphase catalytic reactors from their modeling and design to their applications in industrial manufacturing of chemicals Covers theoretical aspects and examples of fixed-bed, fluidized-bed, trickle-bed, slurry, monolith and microchannel reactors Includes chapters covering experimental techniques and practical guidelines for lab-scale testing of multiphase reactors Includes mathematical content focused on design equations and empirical relationships characterizing different multiphase reactor types together with an assortment of computational tools Involves detailed coverage of multiphase reactor applications such as Fischer-Tropsch synthesis, fuel processing for fuel cells, hydrotreating of oil fractions and biofuels processing

Download or read book Heterogeneous Reactor Design written by Hong H. Lee and published by Butterworth-Heinemann. This book was released on 1985 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Good,No Highlights,No Markup,all pages are intact, Slight Shelfwear,may have the corners slightly dented, may have slight color changes/slightly damaged spine.

Download or read book Modeling and Simulation of Catalytic Reactors for Petroleum Refining written by Jorge Ancheyta and published by John Wiley & Sons. This book was released on 2011-04-20 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and Simulation of Catalytic Reactors for Petroleum Refining deals with fundamental descriptions of the main conversion processes employed in the petroleum refining industry: catalytic hydrotreating, catalytic reforming, and fluid catalytic cracking. Common approaches for modeling of catalytic reactors for steady-state and dynamic simulations are also described and analyzed. Aspects such as thermodynamics, reaction kinetics, process variables, process scheme, and reactor design are discussed in detail from both research and commercial points of view. Results of simulation with the developed models are compared with those determined at pilot plant scale as well as commercial practice. Kinetics data used in the reactor model are either taken from the literature or obtained under controlled experiments at the laboratory.

Download or read book Activation Deactivation and Poisoning of Catalysts written by John Butt and published by Elsevier. This book was released on 2012-12-02 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Activation, Deactivation, and Poisoning of Catalysts deals with the circumstances and mechanisms underlying catalyst activation, deactivation, and poisoning. The emphasis is on the techniques for handling deactivating systems, not on results per se. Deactivation by fouling and sintering is given consideration. This book is organized into three sections and consists of 12 chapters. The first part is devoted to a systematic development of the manner in which catalysts are activated, deactivated, poisoned, and in some cases reactivated on a microscopic basis. The first chapter explains the concept of the active center as utilized in catalysis, along with catalyst regeneration, rejuvenation, and detoxification. In the second part, the reader is introduced to the problem of heat transfer as well as the transport of reactants and products in the interior of the particle coupled with chemical reaction therein. The macroscopic deactivation behavior of the catalyst particle is described in terms of fundamental kinetic deactivation phenomena and of parameters governing heat and mass transfer. The last part is primarily concerned with a collection of catalyst particles within the reactor, with emphasis on the global activity of the reactor. In the last chapter, a pragmatic approach is presented to predict the design and performance of chemical reactors containing a deactivating catalyst. This book is written for catalytic chemists, researchers, reactor designers, and students interested in catalyst activation, deactivation, and poisoning.

Download or read book Chemical and Catalytic Reactor Modeling written by American Chemical Society. Meeting and published by . This book was released on 1984 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deactivation of Catalysts written by Ronald Hughes and published by . This book was released on 1984 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalysis by Metals and Alloys written by V. Ponec and published by Elsevier. This book was released on 1995-08-29 with total page 745 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysis by Metals and Alloys

Download or read book Deactivation Modeling of Cobalt Fischer Tropsch Catalysts in Different Reactor Configurations written by Majid Sadeqzadeh and published by . This book was released on 2012 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalyst deactivation remains a major challenge in Fischer-Tropsch synthesis; as it reduces the catalyst lifetime as well as its productivity. Deactivation can be attributed to certain mechanisms according to the literature. Sintering is proposed in this work to be responsible for the initial deactivation whereas coking is suggested to be the main cause of long-term deactivation. The final objective of this thesis is to develop the mechanistic models which could predict the extent of catalyst deactivation with time. In the first step, the change in the catalyst physico-chemical properties with time on stream is considered. A three-step sintering model is proposed which involves the effect of water acceleration through the formation of surface cobalt oxide layer. This mechanism allows correlating the crystallites growth with certain operating conditions especially the H2O/H2 molar ratio inside the reactor. We have also developed a mechanism for the active site poisoning by carbon deposition for the long-term deactivation. This mechanism helps to evaluate the change in the active sites coverage with time as well the CO, H2, and H2O mole fractions. The two microscopic models are then integrated in the reactor models in order to correlate the change in the catalytic activity with the catalyst properties. We have developed the models dedicated to fixed bed and slurry reactors. The effect of operating conditions on the crystallite size, active sites fraction, and conversion is considered by the simulations. The models are then employed in the laboratory scale reactors to fit the experimental data and to optimize the deactivation constants.

Download or read book Dynamic Behaviour of a Fixed bed Catalytic Reactor with Catalyst Deactivation written by and published by . This book was released on 1994 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deactivation and Poisoning of Catalysts written by J. Oudar and published by CRC Press. This book was released on 1985-07-02 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deactivation and Poisoning of Catalysts presents the most current research in the area of heterogeneous catalysis. It focuses on the chemically induced effects associated with bonded surface species that cause catalyst activity decline -- and in some cases a change in catalyst specificity. In addition, this volume examines poisoning of dispersed metal catalysts ... the thermodynamics of sulfur-metal and carbon-metal interactions ... model poisoning reactions on single crystals ... deactivation in petroleum refining and petrochemical processes ... coking of metal catalysts ... and more. The new approaches and solutions to catalyst deactivation and poisoning presented in this guide are invaluable to all heterogeneous catalysis specialists, including chemical and petroleum engineers, and surface, synthetic, physical, and industrial chemists. Book jacket.

Download or read book Structured Catalysts and Reactors written by Andrzej Cybulski and published by CRC Press. This book was released on 2005-11-02 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in structured catalysts is steadily increasing due to the already proven, as well as potential, advantages of these catalysts. Updating the comprehensive coverage of the first edition published in 1998 with the latest science and applications, Structured Catalysts and Reactors, Second Edition gives detailed information on all aspect

Download or read book Catalytic Reactor Design written by M. Orhan Tarhan and published by McGraw-Hill Companies. This book was released on 1983 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: