Author: Mark Allan ApplegatePublisher:
ISBN:
Category : Chemical reactors
Languages : en
Pages : 178
Book Description
Computer Modeling of Fluid Flow and Heat Transfer in a Fixed Bed Reactor with Finite-element Analysis
Author: Mark Allan ApplegatePublisher:
ISBN:
Category : Chemical reactors
Languages : en
Pages : 178
Book Description
Modeling of Fluid Flow and Heat Transfer in a Packed Bed Reactor of Low Tube to Particle Diameter Ratio with Finite Element Analysis
Author: Beth A. CooperMultiphase Flow and Heat Transfer in Pebble Bed Reactor Core
Author: Shengyao JiangPublisher: Springer Nature
ISBN: 9811595658
Category : Science
Languages : en
Pages : 510
Book Description
This book introduces readers to gas flows and heat transfer in pebble bed reactor cores. It addresses fundamental issues regarding experimental and modeling methods for complex multiphase systems, as well as relevant applications and recent research advances. The numerical methods and experimental measurements/techniques used to solve pebble flows, as well as the content on radiation modeling for high-temperature pebble beds, will be of particular interest. This book is intended for a broad readership, including researchers and practitioners, and is sure to become a key reference resource for students and professionals alike.
Process Modelling and Simulation with Finite Element Methods
Author: William B. J. ZimmermanPublisher: World Scientific
ISBN: 9789812387936
Category : Mathematics
Languages : en
Pages : 404
Book Description
This book presents a systematic description and case studies of chemical engineering modelling and simulation based on the MATLAB/FEMLAB tools, in support of selected topics in undergraduate and postgraduate programmes that require numerical solution of complex balance equations (ordinary differential equations, partial differential equations, nonlinear equations, integro-differential equations). These systems arise naturally in analysis of transport phenomena, process systems, chemical reactions and chemical thermodynamics, and particle rate processes. Templates are given for modelling both state-of-the-art research topics (e.g. microfluidic networks, film drying, multiphase flow, population balance equations) and case studies of commonplace design calculations -- mixed phase reactor design, heat transfer, flowsheet analysis of unit operations, flash distillations, etc. The great strength of this book is that it makes modelling and simulating in the MATLAB/FEMLAB environment approachable to both the novice and the expert modeller.
Chemical Reactor Modeling
Author: Hugo A. JakobsenPublisher: Springer Science & Business Media
ISBN: 3540686223
Category : Technology & Engineering
Languages : en
Pages : 1244
Book Description
This book closes the gap between Chemical Reaction Engineering and Fluid Mechanics. It provides the basic theory for momentum, heat and mass transfer in reactive systems. Numerical methods for solving the resulting equations as well as the interplay between physical and numerical modes are discussed. The book is written using the standard terminology of this community. It is intended for researchers and engineers who want to develop their own codes, or who are interested in a deeper insight into commercial CFD codes in order to derive consistent extensions and to overcome "black box" practice. It can also serve as a textbook and reference book.
Energy Research Abstracts
Author: Computational Flow Modeling for Chemical Reactor Engineering
Author: Vivek V. RanadePublisher: Academic Press
ISBN: 0125769601
Category : Science
Languages : en
Pages : 476
Book Description
The book relates the individual aspects of chemical reactor engineering and computational flow modeling in a coherent way to explain the potential of computational flow modeling for reactor engineering research and practice.
Scientific and Technical Aerospace Reports
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 488
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Applied mechanics reviews
Author: CFD Simulation and Experiment of Catalyst Deactivation and Heat Transfer in a Low N Fixed-bed Reactor
Author: Mohsen BehnamPublisher:
ISBN:
Category :
Languages : en
Pages : 358
Book Description
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.