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Title:
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The use of compact heat exchangers in heat-integrated distillation colums
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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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1-9-2005
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ECN report number:
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Document type:
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ECN-RX--05-156
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Conference Paper
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Number of pages:
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Full text:
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20
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Download PDF
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Presented at: 5th Int. Conf. on Enhanced, Compact and Ultra-Compact Heat Exchangers: Science, Engineering and Technology, Whistler, Canada, 11-16 september 2005.
Abstract:
The Heat-Integrated Distillation Column (HIDiC), in which heat
is transferred directly from the rectification section to the stripping
section of the column, has a much higher energy efficiency than either
a normal distillation column or a vapour-recompression column. Although
the HIDiC concept has been researched for a number of years, it has
not yet been commercialised. Recent literature describes an embodiment
of the concept, which resembles a shell-and-tube heat exchanger. However
an alternative embodiment based on a compact (plate) heat exchanger
has several potential advantages over the shell-and-tube design. These
advantages include compactness, a closer temperature approach, modular
structure, and flexibility in design.
In order to investigate the feasibility of a HIDiC design based
on a plate-fin heat exchanger, a computer program has been developed.
This approach is based on an existing model for conventional distillation,
coupled to a spreadsheet program that incorporates correlations for
such factors as flooding, wetting, and fin efficiency, and that takes
account of geometric constraints in the plate-fin design. The software
was applied in a preliminary case study for a propane-propene splitter.
This confirmed the scope for energy savings, with energy savings of
about 37% compared to a vapour-recompression column. First indications
suggest that the economics may also be favourable. It was concluded
that the plate-fin design is feasible in principle. However the required
hydraulic diameter was larger than currently available in commercial
plate-fin heat exchangers.
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