The superstructure approach to process design provides
a systematic framework for simultaneous optimization
of the process configuration and operating
conditions (Floudas, 1995). Superstructures have been
proposed for a number of membrane separation systems,
including reverse osmosis (Zhu, El-Halwagi &
Al-Ahmad, 1997) and pervaporation (Srinivas & ElHalwagi,
1993) networks. For gas separation systems,
the basic components of the superstructure are permeators,
compressors, stream mixers and stream splitters.
The superstructure for multicomponent membrane separation
systems is derived as described. Note that
each separation stage may comprise several permeators
in parallel.