New synthesis framework for the optimization of complex distillation systems
Shah, P.B., Kokossis, A.C.
AIChE Journal, vol.48, no.3, p.527-550
A new synthesis framework screens and examines complex distillation sequences. Conventional superstructure developments are replaced in favor of a novel representation that assumes the form of a supertask model The supertask is based on simple tasks that accommodate for basic sequences. Hybrid tasks account for complex columns and sloppy splits. Discrete instances of simple tasks are combined with hybrid transformations to optimize operating conditions. The optimization problem is formulated as a simple MILP problem that is possible to solve to global optimality. The proposed representation can develop different nonconventional and novel designs featuring fully integrated columns, parallel sequences, and multiple-effect columns. The approach is illustrated with several literature and industrial problems. In all cases solutions are reported in the form of nonconventional designs that perform as optimal or near-optimal schemes.