Improving batch reactors using attainable regions: Towards automated construction of the attainable region and its application to batch reactors
Date
2015-05-12
Authors
Ming, David
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Abstract
The Attainable Region is the set of all achievable states, for all possible reactor
configurations, obtained by reaction and mixing alone. It is a geometric method
that is effective in addressing problems found in reactor network synthesis. For this
reason, Attainable Region theory assists towards a better understanding of systems
of complex reaction networks and the issues encountered by these systems.
This thesis aims to address two areas in Attainable Region theory:
1. To help improve the design and operation of batch reactors using Attainable
Regions.
2. To further advance knowledge and understanding of efficient Attainable Region
construction methods.
Using fundamental concepts of mixing and attainability established by Attainable
Region theory, a graphical method of identifying opportunities for improving the
production rate from batch reactors is first presented. It is found that by modifying
the initial concentration of the batch, overall production performance may
be improved. This may be achieved in practice by retaining a fraction of the final
product volume and mixing with fresh feed material for subsequent cycles. This result
is counter-intuitive to the normal method of batch operation. Bypassing of feed
may also be used to improve production rate for exit concentrations not associated
with the optimal concentration. The graphical approach also allows optimisation of
batches where only experimental data are given.
An improved method of candidate Attainable Region construction, based on
an existing bounding hyperplanes approach is then presented. The method uses a
plane rotation about existing extreme points to eliminate unachievable regions from
an initial bounding set. The algorithm is shown to be faster and has been extended
to include construction of candidate Attainable Regions involving non-isothermal
kinetics in concentration and concentration-time space.
With the ideas obtained above, the application of Attainable Regions to batch
reactor configurations is finally presented. It is shown that with the appropriate
transformation, results developed from a continuous Attainable Region may be used
to form a related batch structure. Thus, improvement of batch reactor structures is
also possible using Attainable Regions. Validation of candidate Attainable Regions
is carried out with the construction algorithm developed in this work.