A Scheduling Model Framework for Crane-Assisted Pipeless Process Plants

Abstract

In this work, for the first time, we present a general framework for the scheduling of crane-assisted pipeless batch (and semibatch) process plant operations. Using the framework, we develop a precedence-based continuous-time mixed integer linear programming (MILP) model for the short-term real-time operational scheduling of such plants. Of particular concern is the use of cranes as a resource for vessel-transfer, during which inter-crane collision must be avoided, for which we make a comprehensive presentation. Combined with this are the vessel-transfer restrictions arising due to vessel-carrying capacity limitations and operational requirements at processing equipment of such plants. Also of consideration is the possible utility of intermediate stands for temporary storage of vessels in-between operations, which brings a modeling challenge in the continuous-time framework. We demonstrate the utility of the presented framework by applying it to four different problem settings that arise from operations in crane-assisted pipeless batch process plant environments. We believe that the work will serve the way forward to provide immediately retrievable, safely implementable, operational decision-making capabilities in real-time for crane-assisted pipeless batch process plants, enabling a more productive, automated operation of such volatile environments.