The tragic accidents at Flixborough and Bhopal have led to the
development of new legislation
concerning the design and operation of chemical plants. In
addition, the growing concern with
safety and environmental issues places many new demands upon the
designer. Process plant
layout, as an important step in the design of chemical plants, is
effected by these demands.
This paper presents a new approach to process plant layout that
integrates safety and economics.
In this approach, the cost of a layout is a function of piping
cost, land cost, financial risk, and
protection devices cost. The financial risk term captures the risk
of unsafe plants and can be
expressed as the expected losses if major accidents happen (i.e., fires
or explosions). The proposed
approach is a mixed-integer nonlinear optimization problem (MINLP) that
identifies attractive
layouts by minimizing overall costs. This approach gives the
coordinates of each unit, an estimate
for the total piping length, the amount of land occupied, and the
safety devices that have to be
installed at each unit.