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Title:
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Inorganic membranes for pervaporation: proof of concept
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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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1-6-2004
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ECN report number:
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Document type:
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ECN-C--04-106
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ECN publication
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Number of pages:
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Full text:
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53
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Download PDF
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Abstract:
The aim of the here described project was to develop membranes,
modules and systems to come to a quick implementation of tubular inorganic
membranes in dewatering pervaporation processes in the process industry
as a cost effective and energy efficient alternative for e.g. distillation.
Based upon commercially available ceramic support tubes microporous
silica membranes for pervaporation have been made using fully automatic
techniques on a commercial scale. The production facility has been designed
for an output of 12,000 tubes (or about 500 m2) annually.
Dehydration of several organic mixtures using these membranes has been
performed from lab scale up to a scale of 1 m2 of membrane
area and shows good selectivities and fluxes that are much higher than
for polymeric membranes. Process calculations for some processes show
high energy savings and favourable economics.
The silica membranes however show flux decline in time (at
an almost constant selectivity) and the membrane performance has been
improved by incorporating methyl groups into the silica structure. This
methylated silica membrane now meets the long term flux demands as needed
in industrial processes. As the silica based membrane shows a structural
reorganisation at temperatures above 100oC, the use is at
this moment limited to this temperature. Membrane fouling due to salts
in the feed mixture in combination with membrane cleaning is a topic
for further research.
An isothermal module for the inorganic pervaporation membranes
has been developed and optimised by chemical engineering and computational
fluid dynamics calculations towards heat transfer and pressure drop.
Also costs for membrane systems have been optimised by smart module
arrangements in a pervaporation set-up. Modules up to 5 m2
and designs for larger scale modules have been made.
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