Design

Engineering is ultimately about making things for the benefit of society. We typically use the term design for the set of instructions by which a craftsperson can turn an idea into an object, and that meaning of the word carries over to the engineering activity of making tangible objects. Design has an additional meaning for a chemical engineer, however; it is the conceptualization of a process for manufacturing something – a chemical, perhaps. In this use of the word we address the problem of designing what pieces of equipment are needed, how they should be connected, how large they should be, and so on, but we do not address the question of how the equipment should be manufactured – materials of construction, locations of welds, precise geometry, and so forth. It is the second sense of the word that we employ in this chapter. Thus, we will exploit the understanding of reaction kinetics developed in Chapter 6 to determine reactor sizes and material flow rates, but we will view the reactor simply as a vessel of a given size, with no attention to the detail that would be required for actual fabrication.

Process design is a subject that is traditionally taught as a capstone course during the last year of a chemical engineering program, because a complete approach to process design obviously requires a broad base of understanding of chemical engineering fundamentals.