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Simulation of Chemical Reactors

Hertzberg, Tommy LU (1997)
Abstract
This thesis consists basically of two parts. They are, however, interrelated by the fact that both parts concerns modelling of catalytic reaction systems and also by the fact that in both parts, spectral methods are used for simulation. The first part describes the numerical treatment of the dispersion model. The model is used to simulate a packed-bed reactor producing formaldehyde from methanol with an iron/ molybdenum catalyst. The self-adjoint partial differential operators involved in the model can, based on the Spectral theorem, be used to obtain infinite series of ordinary differential equations. After solving these equations, the solution to the original equation is obtained by summation. An advantage of the solution method is the... (More)
This thesis consists basically of two parts. They are, however, interrelated by the fact that both parts concerns modelling of catalytic reaction systems and also by the fact that in both parts, spectral methods are used for simulation. The first part describes the numerical treatment of the dispersion model. The model is used to simulate a packed-bed reactor producing formaldehyde from methanol with an iron/ molybdenum catalyst. The self-adjoint partial differential operators involved in the model can, based on the Spectral theorem, be used to obtain infinite series of ordinary differential equations. After solving these equations, the solution to the original equation is obtained by summation. An advantage of the solution method is the possibility to obtain information regarding system behaviour, before actually simulating the system. This information can be extracted from the spectra of eigenvalues obtained after resolving the self- adjoint operators. The second part describes the simulation of heterogeneous/homogeneous combustion where the catalyst is located at the solid wall in contact whith a reactive gas flow. The full equation system, describing compressible fluid flow and chemical reactions, is solved. The numerical solution includes handling of non-linear differential operators which makes the simulation much more difficult than the one performed in part I. The impact of the convective/diffusive operators involved in the simulations become differently important in different areas in space, i.e. in areas far from the solid phase, the convective part will dominate whereas the diffusive part will dominate close to the solid. In order to resolve each contribution efficiently, a fractional step method was used whereby the equation systen was divided into hyperbolic, parabolic and reaction steps. The different steps were then calculated with spectral methods suitable for each specific type of equation system. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Andersson, Bengt, Göteborg
organization
publishing date
type
Thesis
publication status
published
subject
keywords
fluid flow, chemical reactors, formox, fractional step, catalytic combustion, Spectral methods, self-adjoint operator, Chemical technology and engineering, Kemiteknik och kemisk teknologi
pages
115 pages
defense location
Chemical Center, Lund
defense date
1997-03-07 10:15
external identifiers
  • Other:ISRN: LUTKDH/TKKT--97/1042--SE
language
English
LU publication?
yes
id
e9c5f38c-7153-4d0a-944a-0d1244f5193f (old id 29055)
date added to LUP
2007-06-14 10:51:46
date last changed
2016-09-19 08:45:19
@misc{e9c5f38c-7153-4d0a-944a-0d1244f5193f,
  abstract     = {This thesis consists basically of two parts. They are, however, interrelated by the fact that both parts concerns modelling of catalytic reaction systems and also by the fact that in both parts, spectral methods are used for simulation. The first part describes the numerical treatment of the dispersion model. The model is used to simulate a packed-bed reactor producing formaldehyde from methanol with an iron/ molybdenum catalyst. The self-adjoint partial differential operators involved in the model can, based on the Spectral theorem, be used to obtain infinite series of ordinary differential equations. After solving these equations, the solution to the original equation is obtained by summation. An advantage of the solution method is the possibility to obtain information regarding system behaviour, before actually simulating the system. This information can be extracted from the spectra of eigenvalues obtained after resolving the self- adjoint operators. The second part describes the simulation of heterogeneous/homogeneous combustion where the catalyst is located at the solid wall in contact whith a reactive gas flow. The full equation system, describing compressible fluid flow and chemical reactions, is solved. The numerical solution includes handling of non-linear differential operators which makes the simulation much more difficult than the one performed in part I. The impact of the convective/diffusive operators involved in the simulations become differently important in different areas in space, i.e. in areas far from the solid phase, the convective part will dominate whereas the diffusive part will dominate close to the solid. In order to resolve each contribution efficiently, a fractional step method was used whereby the equation systen was divided into hyperbolic, parabolic and reaction steps. The different steps were then calculated with spectral methods suitable for each specific type of equation system.},
  author       = {Hertzberg, Tommy},
  keyword      = {fluid flow,chemical reactors,formox,fractional step,catalytic combustion,Spectral methods,self-adjoint operator,Chemical technology and engineering,Kemiteknik och kemisk teknologi},
  language     = {eng},
  pages        = {115},
  title        = {Simulation of Chemical Reactors},
  year         = {1997},
}