Support of Scheduling of Multiproduct Pipeline Systems Using Simulation in Witness

Abstract

In this paper, we describe the efficient discrete modelling of multiproduct pipeline systems in Witness simulation software environment. Our simulation model consists of 6 blocks called System structure, Pumping modes, Pumping schedule, Pumping execution, Collecting of outputs and Simulation run control and is supported by MS Excel. Algorithm for the assignment of a scheduled pumping requirement to execution is proposed too. Our model is innovative in that pipelines for the transport of products, tanks for storing products in warehouses as well as the products themselves and their material flow are represented neither by the continuous physical elements (Pipes, Tanks, Fluids) nor their discrete equivalent (Conveyors, Buffers, Parts) but by the logical elements called Variables. Avoiding physical elements enables efficient modelling of bidirectional flow of products in a pipeline and furthermore leads to the high speed of a simulation run. Based on the outputs of simulation of a simple pipeline system we show how our model can be used to support scheduling in complex multiple sources, multiple destinations pipeline networks.