A continuous time model for a short-term multiproduct batch process scheduling

Abstract

In the chemical industry it is common to find production systems characterized by having a single stage or a previously identified bottleneck stage, with non-identical parallel stations and with configuration or preparation costs depending on the production sequence. This paper proposes a mixed integer production scheduling model that seeks to identify lot size and product sequencing with the objective of maximizing profit. In addition, it considers multiple typical industry conditions, such as penalties for noncompliance and out of service periods of units (or stations) for preventive maintenance activities.The model was validated with real data from a chemical company and a 12% reduction in the total cost of production and a 19% increase in the estimated profit. In addition, we applied the model to 155 instances generated using Monte Carlo simulation, based on historical data from the same company, to analyze its performance.