(408d) Energy-Efficient Complex Column Synthesis

Zhang, L., University of Illinois at Chicago
Moon, J., University of Illinois at Chicago
Grosman, B., University of California, Santa Barbara
Linninger, A. A., University of Illinois at Chicago

Complex distillation column configurations are
estimated to harness energy savings up to 70%. Distillation synthesis with
complex configuration is a meaningful target for energy improvements on an industry-wide
scale. In this presentation, we demonstrate a hybrid algorithm combining
stochastic search techniques with complex distillation configuration. An
evolutionary algorithm will construct automatically structurally different
complex separation network with the complex basic distillation configuration.
Feasibility of the design will be delegated to an advanced feasibility tests
based on temperature collocation of finite elements. Application will
demonstrate the algorithms performance in complex column sequencing problems
for real industrial application.

In this presentation, a generalized column section approach to draw
distillation column configurations to separate an ideal to near ideal
n-component mixture into n product streams or less will be presented. The
stochastic evolutionary with novel temperature collocation method was
incorporated to systematically find a set of optimum distillation schemes for a
given application. The structure and length of configuration will not be
predefined anymore and will be optimally sought by stochastic evolutionary. After
we obtain an array of the optimal configurations and operating conditions, we
will identify whether the current separation network is among of those results.
The rigorous simulation and energy comparison will be implemented in commercial
flowsheet software (HYSYS) with the help of the optimal results from the
proposed methodology.

The major innovation of the proposed approach is
an evolutionary program combined with a novel temperature collocation algorithm
to systematically build and optimize complex column configurations based on
column sections. The evolutionary algorithm constructs automatically different
separation sequences; feasibility of the synthesized sequences is ascertained
by means of the minimum bubble point distance. Finally, realistic solutions
will be constructed and determined by the commercial flowsheet simulation
(HYSYS) initialized by the proposed approach.