 |  Plant Design and Economics for Chemical Engineers, 5/e Max S. Peters,
University of Colorado
Klaus Timmerhaus,
University of Colorado, Boulder
Ronald E. West,
University of Colorado, Boulder
Flowsheet Synthesis and Development
Chapter OverviewA
s noted earlier, a schematic representation of a chemical process is made by the use
of a flowsheet. The preparation of such a flowsheet encompasses the steps of synthesis,
development, evaluation, and selection of the most appropriate processing
arrangement of a chemical process. The development of a flowsheet involves a branching
nature resulting from the multiple possible types and arrangements of equipment and from
the selection of process and equipment conditions. This cascading nature in the flowsheet
development creates complexities and intricacies in any process-design investigation.
However, by constructing increasingly complex and complete flowsheets in an orderly
fashion and then rationally evaluating them, it is possible to obtain optimal or near optimal
results. Selection of the flowsheet is one of the most important steps in the design of
a chemical plant, because only from the most optimal flowsheet can the most profitable,
safe, and environmentally sound final design be obtained.
This chapter discusses two design procedures for flowsheet synthesis and design,
namely, the hierarchical and algorithmic methods. The former is based on heuristic rules
derived from past experience, and the latter utilizes mathematical programming procedures
that include optimization techniques. The hierarchical approach has been used
with reasonable success in flowsheet development of more routine chemical processes
but with considerably smaller success in the more complex chemical processes. The
algorithmic approach has had similar experiences in flowsheet synthesis since most
conventional algorithmic methods require the manual construction of the complete network
containing all possible flowsheets, many of which are infeasible. However, some
recent work by Friedler and Fan and their associates is providing some valuable insights
as to how the approach through computerization can become a valuable tool in the
synthesis of more complex chemical processes. To demonstrate the procedures involved,
each approach is used to synthesize and develop an acceptable flowsheet for the
production of the same chemical product, vinyl chloride.
The intuitive approach for methodically developing a set of flowsheets is through
a multilevel analysis of process requirements and a hierarchical synthesis of potential
processes. The essence of this approach is to generate from processing requirements a
number of more concrete functions, which are then expanded into better-defined operations.
These operations are then integrated into a final flowsheet. |
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2003 McGraw-Hill Higher Education