The process plant layout problem involves decisions
concerning the spatial allocation of equipment items
and the required connections among them (Mecklenburgh,
1985). Usually, these plant layout decisions are
ignored or do not receive appropriate attention during
the design or retrofit of chemical plants. However,
increased competition leads contractors and chemical
companies to look for potential savings at every stage
of the design process. In general, the process plant
layout problem may be characterised by a number of