Page 82 - Design of Simple and Robust Process Plants

Design of Simple and Robust Process Plants. J. L. Koolen 67
Copyright 2002 Wiley-VCH Verlag GmbH & Co. KGaA
ISBNs: 3-527-29784-7 (Hardback); 3-527-60047-7 (Electronic)

Chapter 4
Process Synthesis and Design Optimization

Process synthesis and design optimization is the most important part of a design. It
determines the efficiency and the economics of the process plant. Nevertheless the
importance of this activity there wasn't an structural approach developed over the
years up to the last decades. The approach taken so far was based on an evolutionary
process. Step by step the processes were improved hand in hand with opportunities
which were identified and developed at research. The objective of process synthesis
and design optimization is to systematically evaluate design alternatives to derive at
the optimal process. In this chapter a step wise methodology is described how to
derive at an optimal designed process.
The conceptual process design to achieve high-quality processes is a layered
approach based on the conventional ªonionº model as discussed by IChemE (1982)
and by Smith and Linnhoff (1988), see Figure 3.3. A more detailed hierarchical
approach to conceptual design was published in the trendsetting book, Conceptual
Design of Chemical Processes (Douglas, 1988). Hierarchical, layered approaches have
been discussed in great detail more recently Douglas and Stephanopoulos, 1995,
Biegler et al., 1997; Seider et al., 1999). The conceptual design developed along the
layers, from inside to outside in the onion model was presented in the following
sequential order:

. reactor
. separation and recycle system
. heat exchanger network
. utilities
In this chapter the onion model will be broadened with integration (a wider term
than heat exchange network), controllability and site integration (a much broader
field than utilities).
The layers in the adapted onion model are:
. reactor
. separation and recycle system
. integration
. controllability
. site integration