Multi-objective optimization system for plant layout design (3rd report, Interactive multi-objective optimization technique for pipe routing design)

Plot plan drawings in the process and power industries are considered key decision-making documents for projects and are normally initiated in the pre-contract, conceptual, and developmental stages of a proposal. These drawings indicate the locations of the main equipment and building structures at a plant that contain pipes and cable connections between equipment units. This study proposes a multi-objective pipe and cable routing optimization method for a thermal power plant based on effective interactions between a designer and computer. We applied an interactive satisficing trade-off method and genetic algorithms to perform combinatorial optimization with multiple objectives. To obtain pipe and cable route candidates for multiple-criteria decision-making, we applied an ant colony optimization algorithm to a rule-based automatic layout of pipe racks. The features of this method can be optimized simultaneously not only for pipe and cable routes, but also for the placement of pipe racks among multiple conflicting evaluation functions. These functions may include the total cost of the pipes and cables, total length of the pipe racks, number of roads straddled by pipe racks, and total number of pipes and cables on a pipe rack. Finally, the validity and usefulness of this method is demonstrated by solving a layout design problem involving pipe and cable routing for a gas-turbine combined-cycle power plant.