Safety-based process plant layout using genetic algorithm

• Method based on a genetic algorithm for optimizing process plant layout is presented.
• Total annual cost including piping, pumping, costs, and expected annual loss is minimized.
• Improves existing approaches by factoring in pumping cost and probabilistic risk assessment.
• We demonstrate that safety-related costs are relevant for defining optimal layout.
• Limitation of layout design based on predefined safety distances only is overcome.

This paper presents a method based on a genetic algorithm for optimizing process plant layout. The relative location of main process units is determined to minimize an annual cost function including the cost of material transfer between process units (piping and pumping costs), land cost, and the expected annual loss resulting from damage to each secondary unit caused by primary accidents occurring in nearby process units. This method is an improvement over previous attempts using genetic algorithms or mathematical programming techniques to optimize plant layout, which neglected pumping costs and included safety issues by evaluating the infringement of predefined safety distances only. In this approach the operating cost of material transfer is included and the likelihood of accidents is taken into account thus providing good practical solutions to the plant layout problem incorporating more realistic cost functions and constraints. In the paper, after discussing the structure of the annual cost function and describing the working logic of the layout generating algorithm, a case study is described to demonstrate the effectiveness of the proposed methodology.