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Special Theme Issue Catalysis and Reactor Engineering.

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Developments in Chemical Engineering
& Mineral Processing
Special Theme Issue
Catalysis and Reactor Engineering
Guest Editorial: Dr A.A. Adesina
Reactor design and operation is the heart of the modern process industry and more than
80% of commercially-importantreactions engage catalysts whether as homogeneous or
heterogeneous species. In an age of depleting natural resources and an increasing
paradigm shift to clean technology, it is expedient that process research focus on both
improvement in extant reactor operation and the optimal implementation of new design
concepts. This has been the underpinning philosophy in the review and selection of
papers for this Special Issue on Catalysis and Reactor Engineering which, in the
spirit of Octave Levenspiel, is the distinguishing attribute of the chemical engineering
profession. As may be expected, many of the contributions are devoted to the
petrochemicals and minerals processing industries.
Heudon and Zhung reported the use of a Cu-loaded natural zeolite for selective
-
catalytic reduction of NO with methane in a tubular packed bed reactor. Glusser and
coworkers have pioneered the concept of the attainable region for systems optimisation.
This geometric method has been applied to the optimal synthesis of a reactor-separatorrecycle system. In another article, they also showed how internal heat exchange can be
used to optimise the design of adiabatic reactors along the optimum temperature
progression path for reversible exothermic reactions. The emerging area of
photocatalysis has significant applications for the design of environmentally-benign
processes and the synthesis of fine chemicals. H o w has presented a very readable
account of the status of this field with emphasis on the design and synthesis of novel
photocatalysts which may be sensitized in the visible region. Issues related to improved
photoreactor operation are also discussed. Still in the context of environmental reaction
engineering, the low-temperature catalytic liquid phase oxidation of a priority pollutant,
4-hydroxy nitrobenzene, has been investigated by Suen and Adaim. The excellent
degradation rate over a CuO-Ti02 catalyst was attributed to chemical synergy.
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Al-Zuhruni's paper examines the merits and disadvantages of various process options
for the aromatization of LPG to high-value-added products. This contribution is
especially valuable for industrial practitioners. Abmueed and A l - B u n i report the
modelling and analysis of a fluidised bed reactor for the polymerisation of ethylene and
propylene - a major operation in the petrochemical industry. Bifurcation diagrams of
the dynamic model showed that due to the polymer softening temperature, reactor
operation must be confined to low temperature stable-monomer conversion. The
importance of bifurcation analysis in reactor design is fiuther demonstrated by Adesina's
paper. He investigated a class of exothermic reactions representative of organic
syntheses and many biological reactions characterised by nonlinear kinetics. Diagnostic
criteria to identify regimes for muItiple steady-states were developed using the Newton
polyhedron method.
McMunus et ul. have studied the copolymerisation kinetics of acrylonitrile and vinyl
acetate. Reactivity ratios were obtained using the error-in-variables model (EVM).Dui
et ul. conducted batch reactor studies for the removal of Pb2' fiom wastewater using
mordenite. They observed that increased pH enhanced the exchange rate (with Na, Ca,
or K), however, the lead exchange capacity was unaffected. Foisy und colluborurors
have employed conjugation operators to model the effect of charge dispersion to
neighbouring atoms on the properties of the parent ion. To illustrate the procedure, the
estimation of heterolytic bond dissociation energies associated with alcohol anions was
derived fiom the model. Al-Zuhruni and Abmueed considered a simple but effective
mathematical fluidized bed model based on the two-phase theory for the oxidative
coupling of methane. The model gave good agreement with independent experimental
data sets under a variety of conditions and high selectivities were shown to be possible
even with large-scale fluidized bed reactors, confirming the potential of the model for
scale-up purposes. Finally, Liung et ul. demonstrated the effectiveness of some
hydrophobic catalysts for the partial oxidation of propylene in a slurry reactor. Clearly,
the scope and rigour of these papers is a testimony to the continued relevance of
catalysis and reactor engineering to our future, especially our dependence on the
economic and environmentally-acceptable conversion of naturally-occuning raw
materials for goods and services.
Dr. A.A. Adesina
School of Chemical Engineering
& Industrial Chemistry
University of New South Wales, Sydney
New South Wales 2052, Australia
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