A resource-task network approach for optimal short-term/periodic scheduling and heat integration in multipurpose batch plants

This article aims to integrate the task scheduling and heat recovery problems into an unified framework for multi-purpose batch processes. The batch scheduling formulation is extended from the continuous Resource-Task Network (RTN) formulation which was originally proposed by Castro et al. [P.M. Castro, A.P. Barbosa-Povoa, H.A. Matos, Optimal periodic scheduling of batch plants using RTN-based discrete and continuous-time formulations: a case study approach, Ind. Eng. Chem. Res. 42 (2003) 3346-3360; P.M. Castro, A.P. Barbosa-Povoa, H.A. Matos, A.Q. Novais, Simple continuous-time formulation for short-term scheduling of batch and continuous processes, Ind. Eng. Chem. Res. 43 (2004) 105-118]. Besides the integrated heat recovery and short-term batch scheduling, a full set of heat-integrated periodic scheduling for batch processes, which is more useful in industrial environments, is also presented. The heat-integrated batch scheduling problem can be formulated as a mixed-integer linear program (MILP), where the new formulation can also be solved in standalone or heat-integrated modes by user's preferences. In the heat-integrated mode, the processes can be precisely defined while keeping the operation flexibility with slightly expanded model size. Two literature examples are demonstrated to show the efficiency and flexibility of the model. (C) 2008 Elsevier Ltd. All rights reserved.