Page 19 - Chemical engineering design

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CHEMICAL ENGINEERING
Region of all designs
Safety regulations Resources Physical laws
Choice of
process
Process
conditions
Plausible
Economic constraints Methods Possible designs Personnel Materials Standards and codes
designs
Time

Government controls

“External” constraints
“Internal” constraints
Figure 1.1. Design constraints

Objective
(design
specification)

Collection of data,
physical
properties design
methods

Generation of
possible designs

Selection and
evaluation
(optimisation)

Final
design

Figure 1.2. The design process

The stages in the development of a design, from the initial identification of the objective
to the final design, are shown diagrammatically in Figure 1.2. Each stage is discussed in
the following sections.
Figure 1.2 shows design as an iterative procedure; as the design develops the designer
will be aware of more possibilities and more constraints, and will be constantly seeking
new data and ideas, and evaluating possible design solutions.