A. Machac , R. Henda , and B. Nilsson 
 School of Engineering, Laurentian University, Sudbury, ON, Canada
 Lund University, Sweden
Heat and mass transport phenomena in a tubular catalytic bed reactor are numerically investigated. A two-dimensional pseudo-heterogeneous model, accounting for transport in the solid and fluid phases, with axial and radial dispersions, is used to describe the reactor. The calculation results show the development of a hot spot in the reactor. The effects of inlet process conditions are ...
A theoretical and experimental analysis of membrane bioreactors behavior in unsteady-state conditions
Department of Chemical Engineering and Materials University of Calabria, Rende (CS), ITALY
The behavior of hollow fiber membrane bioreactors operating in recycle configuration is characterized from both theoretical and experimental point of view. The theoretical model is based on the unsteady-state balance equations governing momentum and mass transfer within the regions that can be identified in a hollow fiber reacting system with immobilized enzyme, coupled to the unsteady-state mass ...
Computations on the coupled heat and mass transfer during fires in bulk materials, coal deposits and waste dumps
Krause, U., Schmidt, M., Lohrer, C.
Federal Institute for Materials Research and Testing (BAM), Division II.2 “Reactive Substances and systems”, Berlin, Germany
In porous combustible matter low-rate oxidation takes place at ambient conditions. In large stockpiles of bulk goods, coal heaps, waste dumps etc. it may occur that the heat released by the oxidation reaction is not fully transmitted to the surroundings but raises the temperature within the deposit. This triggers a positive feed-back loop since the oxidation rate increases with temperature. The ...
M. Yang, A. Young, and B. Crittenden
Department of Chemical Engineering University of Bath, Bath, United Kingdom
A small batch stirred cell which is operated at temperatures up to 400 °C and pressures up to 30 bar is used to study fouling behaviors of selected crude oils. COMSOL Multiphysics package is used for the CFD (Computational Fluid Dynamics) and heat transfer modeling for this stirred cell system. The simulation results are validated against the measured temperature data at various axial ...
Humboldt Universität Berlin, IGB, Berlin, GERMANY
In vielen Berechnungen des Umweltschutzes, der chemischen Verfahrenstechnik, der Energietechnik und weiteren Bereichen von Wissenschaft und Technik, spielen Transport- und Reaktionsprozesse gleichermaßen eine Rolle. Aufgrund der Wechselwirkung zwischen Transport und Reaktion ist das Verständnis derartiger Systeme schwierig. In der Regel werden daher Modelle eingesetzt, um derartige Situationen ...
Chalmers University of Technology, Sweden
In this paper, we perform simulations of the auto-thermal reforming of a hydrocarbon fuel in a monolithic reactor. The partial differential equations describing mass, heat and momentum transport were formulated and solved using COMSOL Multiphysics. It was found that mass transport limitations in the washcoat could also severely limit the rate of the reforming reaction. Heat transport ...
C. Bayer, S. Stiefel, M. Follmann, and T. Melin
AVT Chemical Process Engineering, RWTH Aachen University, Aachen, Germany
Reactive extraction of organic acids from an aqueous solution to an alkaline stripping fluid is based on a selective barrier allowing permeation of non-polar molecules, which subsequently react with the stripping agent. The shift from the organic acid to its base induced by the chemical equilibrium enhances mass transfer inside the membrane’s porous substructure. A model of the porous layer ...
Study of the CO2 Transfer Rate in a Reacting Flow for the Refined Sodium Bicarbonate Production Process
C. Wylock, A. Larcy, P. Colinet, T. Cartage, and B. Haut
Université Libre de Bruxelles, Brussels, Belgium
Solvay S.A., Brussels, Belgium
This work deals with the quantification of the CO2 transfer rate from a bubble to the surrounding liquid in a bubble column. A model is successfully developed using COMSOL Multiphysics. The validated model is used to study the enhancement influence of chemical reactions on the transfer rate. Moreover, the results of this study are compared with a classical 1-D approach and excellent comparison is ...
Simulation of Differential Ion Mobility (DMS) Principle Coupled with Mass Spectrometry in Atmospheric Pressure
F. Sinatra, T. Wu, A. Avila, E. Nazarov, T. Evans-Nguyen, J. Wang
Draper Laboratory, Tampa, FL, USA
University of South Florida, Tampa, FL, USA
Mass spectrometry is an analytical technique widely used in the scientific community to determine chemical composition of sample compounds. Typically, mass spectrometers perform their analysis under vacuum conditions, though atmospheric pressure mass spectrometers are becoming more prevalent. With the development of atmospheric pressure mass spectrometers, techniques such as FAIMS (Field ...
J. Knox, R. Coker, R. Cummings, C. Gomez, G. Schunk
NASA, Marshall Space Flight Center, Huntsville, AL, USA
Some NASA efforts are focused on improving current systems that utilize fixed beds of sorbent pellets by evaluating structured sorbents, seeking more robust pelletized sorbents, and examining alternate bed configurations to improve system efficiency and reliability. For the bulk separation of CO2 and H2O, temperature changes due to the heat of adsorption are significant, requiring modeling and ...