Page 180 - Sustainability in the Process Industry Integration and Optimization

Pro c ess O p timization F r ame w ork s 157

Potential networks
(search space)

CF F

Optimal network

FIGURE 7.3 Reduction in the search space effected by combinatorial axioms
(F = feasible networks, CF = combinatorially feasible networks).

FIGURE 7.4 P-graphs (a) E F (b) E F
representing process
structures that violate
(a) Axiom (S2) or
(b) Axiom (S4).
O 2 O 3 O 2 O 3

B C D C B

O 1 O 1

A
A

7.2.3 The P-Graph’s Mathematical Engine: MSG,
SSG, and ABB
When combined with the structural axioms, P-graph representation
makes it possible to implement effective algorithms for structural
analysis, synthesis, and optimization of process structures. The
maximal structure generation (MSG) algorithm (Friedler et al., 1992a)
generates a superstructure that can be rigorously proved to
incorporate each combinatorially feasible process structure. Then the
solution structures generation (SSG) algorithm (Friedler, Varga, and Fan,