PRODUCTION PLANNING AND SCHEDULING FOR MULTIPURPOSE BATCH CHEMICAL-PLANTS

A computer program for solving the general production planning problem in the case of multi-purpose batch chemical plants is presented. The procedure starts with an evolutionary enumeration of alternative production strategies. First, alternative ways of producing one batch of each of the various products are sought. Then, alternative production lines are constructed for each product by assembling types of batches of this product sequentially on the time axis. Finally, production lines of the same, or different products are set in parallel to form alternative campaign candidates. After the alternative production strategies (campaign candidates) have been generated, they are screened by identifying and rejecting non-dominant (i.e. inefficient) strategies. The screenign procedure is based on some principles of linear algebra and uses a duality between points and hyperplanes in a multi-dimensional space. Finally an optimal production plan is obtained by solving an optimization problem in which production time is allocated to the various production strategies. © 1979.