Abstract
A method for the optimizing process networks of industrial systems and applications to refineries and petrochemicals was discussed. The analytical optimization procedure was designed based on comprehensive economic analysis of process networks for maximising the overall system economics. The anaytical optimization process network comprised of three steps including marketing integration, and the optimization of network flowsheet. Marginal correlations for elements and processing of streams were developed in terms of its market price, cost of production (COP) and value on processing (VOP),and market price.