Unit operations paradigm

The development of a unit operations paradigm in the 1920s was based on the observation that many industrial chemical processes shared common basic operations (crystallization, distillation, evaporation, extraction) and these operations should be the focus rather than the production... 

In a sense, CES was not a paradigm shift, but a natural development of the concerns of the early pioneers at MIT. Their goal had been to develop and illustrate those principles of science upon which chemical engineering operations are based [34] the chemical engineering science movement sought to develop and organise those principles, but in a more general context than unit operations. 

The next major paradigm shift came about with the publication of the textbook Transport Phenomena by Bird et al. (1960) znd Mathematical Methods in Chemical Engineering by Amundson and Aris (1966). These works constituted the scientific pillars of chemical engineering as a discipline and led to a turning away from older, more empirical work. Thus, the core curriculum of chemical engineering consists of unit operations and transport phenomena. 

Every chemical process is a collection of units interconnected by streams. This is the concept of unit operations, the first, and most venerable, paradigm adopted by the fledgling discipline of chemical engineering near the beginning of the twentieth century. 

Since the nineties of the last century, the prevailing paradigm of unit operations has been complemented and partly replaced by a product-orientated approach (Cussler and Moggride, 2011 Hill, 2004 Kind, 1999). Now product properties are in the focus product design strategies and the engineering of advanced materials are the results of this approach. 

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