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Keywords:

  • property clusters;
  • visualization;
  • functionality driven design;
  • process integration;
  • snythesis

Abstract

Standard techniques for process design are based on tracking individual chemical species. Component material balances are at the heart of any design approach. Nonetheless, many design problems are not component dependent, but are driven by properties. Recently, the concept of clustering has been introduced to enable the conserved tracking of surrogate properties. Hence, the process design can be optimized, based on integrating properties instead of chemical species. Systematic techniques have been developed for this new paradigm of property integration to illustrate its applicability. Property integration is defined as a functionality-based, holistic approach to the allocation and manipulation of streams and processing units, which is based on tracking, adjusting, assigning, and matching functionalities throughout the process. Revised lever arm rules are devised to allow optimal allocation while maintaining intra- and interstream conservation of the property-based clusters. The property integration problem is mapped into the cluster domain. This dual problem is solved in terms of clusters and then mapped to the primal problem in the property domain. Several new rules are derived for graphical techniques. Particularly, systematic rules and visualization techniques for the identification of optimal mixing of streams and their allocation to units. Furthermore, a derivation of the correspondence between clustering arms and fractional contribution of streams is presented. This correspondence is employed to minimize the usage of fresh resources by minimizing cluster arms. The selection of optimal values of the augmented property index is also developed. Finally, graphical tools are devised for task identification of property adjustment. The new techniques are illustrated using a case study on fiber recovery in papermaking. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1854–1869, 2004