SUSTAINABLE INTEGRATED PROCESS DESIGN AND CONTROL FOR AN EXTRACTIVE DISTILLATION COLUMN SYSTEM

Abstract

The objective of this paper is to develop a sustainable integrated process design and control
(Sustain-IPDC) methodology for an extractive distillation column system. Previously, IPDC
methodology was developed and able to obtain an optimal solution for the IPDC problem for
chemical processes in a simple and efficient way. However, the IPDC methodology did not
consider sustainability aspect at the early chemical processes design stage. The methodology
can be further extended to consider cost optimality, controllability and sustainability aspects.
Here, the Sustain-IPDC problem for an extractive distillation column that is typically
formulated as a mathematical programming (optimization with constraints) problem, is
solved by decomposing it into six sequential hierarchical sub-problems: (i) pre-analysis, (ii)
design analysis, (iii) controller design analysis, (iv) sustainability analysis, (v) detailed
economics analysis, and (vi) final selection and verification. In the pre-analysis sub-problem,
the concept of driving force is used to locate the optimal design-control-sustainability
solution targets, which are defined at the maximum point of the driving force diagram. The
performance of the methodology was analyzed for styrene – p-xylene separation process. The
results show that the Sustain-IPDC methodology is capable of finding the optimal solution
that satisfies design, control, sustainability and detailed economic criteria in systematic and
efficient manner.