The Adaptive Initial DEsign Synthesizer

A number of experimental chemical process synthesis procedures have been developed with a hierarchical architecture based on both the hierarchical structure of the chemical innovation process and the physical property hierarchy. Examples include PIP (Kirkwood et al, 1988) and BALTAZAR (Mahalec and Motard, 1977). This hierarchical approach is also evident in the Pinch Technology Onion Diagram (Linnhoff and Ahmad, 1983). The hierarchical approach is also the foundation for the two early textbooks on process synthesis methodology (Rudd et al, 1973 Douglas, 1988). 

The AIDES program definitely has its limitations. The internal representation of solution thermodynamics is simplistic it cannot, for example, handle azeotropes. Also, the species allocation, once proposed, is adhered to too rigidly and its task integration capabihty is somewhat weak. In industrial situations, its performance is judged to be good, but only slightly better than conceptual designers that resolve property differences directly in terms of common unit operations. 

However sophomoric the AIDES computer implementation, the hierarchical process synthesis procedure itself offers three important lessons which have had a significant industrial impact—lessons that can be used even manually by conceptual process designers. 

Keep task identification distinct from task integration and equipment design. Think carefully about what needs to be accomplished (tasks), then consider how it will be accomplished (equipment). In other words, remember the architect s maxim, Form follows function.  

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