Page 137 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

In this chapter, an introduction to procedures used for chemical product design is provided. It will be
seen that there are similarities to chemical process design; however, the focus of this chapter is on the
differences between process and product design.

4.1 Strategies for Chemical Product Design

A strategy for chemical product design has been suggested by Cussler and Moggridge [1]. It has four
steps:
1. Needs
2. Ideas
3. Selection
4. Manufacture

Needs means that a need for a product must be identified. This involves dealing with industrial customers
and/or the public. If the business end of a commodity chemical industry determines there is a market for
additional benzene, a process is constructed to make the same benzene product that all other benzene
producers make, probably using the same process technology. If there is a market for the additional

benzene, there will be customers. In contrast, in chemical product design, once the need is established,
then the search for the best product begins.

Ideas means that the search for the best product has begun. This is similar to the brainstorming stage of

the problem-solving strategy to be discussed in Chapter 22. Different ideas are identified as to the best
possible product to serve the need.

Selection involves screening the ideas for those believed to be the best. There are quantitative methods
for this step, and they are discussed later.

Manufacture involves determining how to manufacture the product in sufficient quantities. Unlike

commodity chemicals, this usually involves batch rather than continuous processes.

The four-step process is a simplification that is most applicable to the design of chemical products that
are actually chemicals. For the design of devices, there are additional steps needed. Two such product-

design strategies, suggested by Dym and Little [3] and Ulrich and Eppinger [4] are illustrated in Table 4.1
and compared with the strategy of Cussler and Moggridge [1]. The most significant difference is the
inclusion of different stages of device design not apparent for design of a chemical, although it could be
considered that these steps are all part of the selection and/or manufacture step.

Table 4.1 Comparison of Product Design Strategies