Superstructures heterogeneous systems

The systematic development of superstructures for heterogeneous systems is, in principle, a more difficult task. Consider, for instance a process flowsheet that is composed of reaction, separation, and heat integration subsystems. In theory, one could develop a superstructure by combining the superstructures for each subsystem. However, this approach could lead to a very large MINLP optimization problem. 

As this example indicates, generating superstructures for heterogeneous systems based on specific alternatives at the level of tasks is actually not a very... 

Finally, it should be noted that one of the other approaches being examined for heterogeneous systems relies on physically based representations for reaction and mass and heat transfer, which are commonly treated as aggregated models. Also, Friedler et al. (1991, 1992, 1993) have provided graph-theoretic algorithms to systematically derive superstructures for process nkworks, given a list of unit operations and process streams. 

---