1 Short-Term Scheduling of Batch Plants with Parallel Reactors Forming Mobile Work Groups Muge Erdirik-Dogan * , Ignacio E. Grossmann ‡* and John Wassick † * Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, 15213 † The Dow Chemical Company, Midland, MI, 48667 Abstract We address the problem of short-term scheduling of parallel batch reactors followed by continuously operating finishing trains to form work groups which is motivated by a real world problem at the Dow Chemical Company. The proposed MILP formulation is based on the recent planning model of Erdirik- Dogan and Grossmann (2007), and features additional constraints for handling complex arrangements arising from the workgroups. Several examples are presented to illustrate the proposed model. Keywords: batch reactors, scheduling, sequence-dependent changeovers, mobile work groups, MILP 1. Introduction This work has been inspired by a real world application originating from the specialty chemicals business at the Dow Chemical Company which is characterized by the manufacture of a large product portfolio (see Erdirik-Dogan et al., 2007, 2008). The specialty chemicals business is subject to constant change with respect to the products in the portfolio. The relative demand for individual products can fluctuate widely over time as conditions change in the many markets that are served. The price and profitability among products varies greatly and can shift over time. New product introductions and ‡ Author to whom correspondence should be addressed. E-mail: grossmann@cmu.edu