This thesis is concerned with feasibility of reducing
the energy requirement for mtilticomponent distillation
Four systems of four component ideal mixtures are considered,
using for each system two degrees of recovery (95% and 99.5%)
and two configurations I and lI.
A mathematical model has been developed to predict
the minimum energy sequence for four component mixtures.
Because of the difficulties in solving the equations a
graphical method is devised to deal with the problem.
To develop this method the concept of pseudo-components
is invoked, where a 'pseudo-component' is defined as one
having predetermined values of the properties required
for the design analysis, e.g. K-values, vapour and liquid
A prediction design method has been developed for
four component ideal systems which enables the optimal
sequence to be related for any type of feed, different
degree of recoveries and a set of relative volatilities.
Energy integration is considered between reboilers
and condensers only and then between intermediate heaters
and coolers at the pinch points below and above the feed
plate, respectively. The concept of non-ideality is introduced. Nonideal
systems often occur e.g.industrially significant
mixture for such as Ethanol/Water. Their non-ideality makes
them energy intensive usually because of the high reflux
No general solution is possible but two real mixtures
are considered, Acetone/Cumene /Phenol and Ethanol/Water.
It is shown that the engineering techniques discussed
earlier can be used to produce significant savings in
energy requirement for the two systems.
These techniques are also applied to an industrial
system. The first is the separation of light hydrocarbons,
in a stabilizer, C3/C4 splitter and Gasoline Splitter.
The mixture is nearly ideal in its vapour-liquid
equilibrium relationships and again it is shown that
considerable energy savings are possible.
The conclusions of the work are summarised and
suggestions for further studies in this field are provided.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.