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Title:
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Technical and economic evaluation on the use of membrane reactors for the dehydrogenation of propane to propylene
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Author(s):
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Published by:
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Publication date:
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ECN
Energy Efficiency in Industry
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1998
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ECN report number:
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Document type:
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ECN-RX--97-021
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Article (scientific)
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Number of pages:
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21
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Published in: Paper, presented at the 4th workshop in the European Science Foundation network on catalytic membrane reactors, held in Oslo, No (), , , Vol., p.-.
Abstract:
Inorganic membranes can enhance the conversion of dehydrogenationreactions by separating hydrogen and thereby shifting the equilibrium of this
reaction. In order to judge the technical and economic possibilities of these
membranes the dehydrogenation of propane to propylene has been chosen as
model reaction. Membrane and reactor modelling and calculations in the study
are supported by membrane testing under realistic conditions. The use of
ceramic membranes in an isothermal reactor concept is more attractive than
conventional dehydrogenation processes, even with low selective Knudsen
diffusion membranes. However, this ceramic membrane reactor process is not
yet competitive with e.g. steam cracking processes for propylene production.
An increased driving force or a moderately increased membrane selectivity
does not lead to positive results. Probably the only possibility is the
combination of a high driving force (sweep gas or low permeate pressure) and
a high selective membrane. Propane and propylene prices are the main actors
in the introduction of a dehydrogenation process in general, thus also for
processes based upon membrane reactors. At a price difference (propylene -
propane) of 300 $/tonne or less membrane based dehydrogenation processes will
hardly be economic feasible. In general, membranes to be applied should be
stable under the working conditions. Also, coke formation on the membranes
should not lead to dramatic reduction of permeation and selectivity and
regeneration with steam should not be a problem. Other technical constraints
can be the connection of membranes to the metal housing and construction of
such membrane reactors. Lab scale membrane reactor experiments show important
improvement in conversion and selectivity which, however, do not lead to an
economic viable process. This shows that besides the technical possibilities
also economics should be studied. 6 figs., 4 tabs., 12 refs.
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