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Distillation synthesis toolbox for pre-flowsheet designWilson, Cameron Joseph 15 February 2007 (has links)
Student Number : 9903549T -
MSc dissertation -
School of Process and Materials Engineering -
Faculty of Engineering and the Built Environment / Preliminary evaluations during flowsheet synthesis require simple effective tools for
comparison and elimination of process alternatives. This work investigates three areas
of interest in distillation.
Column profile map theory has simplified complex column investigations. The
predictions of the difference point equation at finite reflux were experimentally
verified for the acetone, methanol and ethanol system in a continuous column
apparatus.
Residue curve analysis is usually limited to systems with four components for
distillation system analysis. An alternative representation, based on combinatorial
topology and temperature sequencing, is introduced for use in high level synthesis
decisions for higher component order systems.
Attainable region (AR) theory is applied to an ideal binary distillation system for a
geometrically based method of cost analysis. A constrained attainable region is
constructed from a series of equilibrium step compositions with varying reflux and
corresponding cost associations. The AR is shown to be useful for costing and
optimization.
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Column Profile Maps: A Tool for the Design and Analysis of Complex Distillation SystemsHolland, Simon Thornhill 31 October 2006 (has links)
Student Number : 9510423G
PhD Thesis
School of Chemical and Metallurgical Engineering
Faculty of Engineering and the Built Environment / Techniques for the design and analysis of simple column separations are well
established. Shortcut design techniques have been employed in the initial design of
these “traditional” distillation systems for a number of years and these columns are
well understood. However, few currently available techniques are useful in the
design of novel or complex configurations. The techniques that are available tend
to be configuration specific. An all inclusive or universal, design and analysis tool,
that can be applied to any and all configurations, is required.
Tapp et al (2004) introduced Column Profile Maps (CPMS) as a means of
addressing this issue. These are maps of composition profiles for column sections
with defined net-molar-flow and reflux ratio. It is suggested that by producing
CPMs for a configuration a designer can essentially superimpose these, determine
feasible operating profiles and hence column operating parameters.
In this thesis we show that this technique can be used to, not only produce quick
and easy complex column designs but gain a comprehensive understanding of the
steady-state operation of these arrangements. We demonstrate this analytical
potential first by application of the CPM technique to the two-product feed
distribution problem. It is shown that feed distribution can lower the minimum
required reflux ratio for non-sharp separations and in some cases produce feasible
separations from previously infeasible product specifications. A composition
region of operation for all distributed feed policies is also found.
The potential for detailed analysis, design and optimisation of complex
configurations is demonstrated via application of the CPM procedure to the fully
thermally coupled (Petlyuk) distillation column at both sharp and non-sharp split
conditions. A detailed design methodology for any configuration results from this.
It is found that the Petlyuk column can operate under five possible bulk/net flow
conditions and that very interesting and counter-intuitive net-molar-flows are
possible. A feasible column parameter region equivalent to the optimality region
(Halvorsen and Skogestad, 2001) is found for zeotropic systems. Importantly a
minimum reflux condition for the Petlyuk column is found. This condition can be
applied to all zeotropic systems for all product specifications. It is also
demonstrated that the CPM technique can be used for design optimisation of
separation systems.
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