This study addresses the short-term scheduling problem for the batch anneal
ing process in the heat treatment of steel coils. Scheduling in the batch a
nnealing process has the following objective: determine the optimal movemen
t plan for satisfying high utilization of shared equipment (a crane, furnac
es, and coolers) among parallel bases. This process is a multipurpose batch
plant which may contain re-entrant flows in the batch annealing cycles and
units in parallel, including sequence-dependent setup time and transfer ti
me. A novel mixed-integer linear programming (MILP) model for the schedulin
g of the batch annealing process is proposed. For large size problems of th
e batch annealing process, a scheduling solution can be obtained by using a
novel algorithm. Although this procedure does not guarantee optimality of
the solution, the computational efficiency was improved and feasible soluti
ons for large problems can be obtained in a reasonable CPU time. Applicatio
n of the proposed model and algorithm is illustrated with several example p
roblems including a problem that consists of 29 pieces of equipment and up
to 24 bases. (C) 1999 Elsevier Science Ltd. All rights reserved.