Integrating routing and scheduling for pipeless plants in different layouts

Pipeless batch plants are built to provide the ability to adapt to fast market changes. The scheduling of pipeless plants adds new challenges to the scheduling of conventional batch plants. This is because of the requirement to consider the allocation of resources and also the plant layout so that vessels can move from one processing station to another without conflict. This research investigates the integrated problem of scheduling and routing in pipeless plants and develops a constraint-based methodology suitable for different layouts. During the scheduling process, besides time and resource allocation, a planner is also called to find possible routes to move vessels from one processing station to the next proposed station. Each of the dynamically generated routes is immediately checked for feasible track allocation so that any infeasible route is discarded as soon as possible to save computational time. A typical scheduling problem and results are described in detail to show how this integrated approach works. (c) 2004 Elsevier Ltd. All rights reserved.