Assumption free modeling and monitoring of batch processes

Modeling strategies currently in use for the monitoring of batch processes where multivariate data are available have some limitations, particularly for batches where the true starting or end point are not the same on an absolute time scale, or the batch progression varies among batches. In this paper, a method capturing these differences and allowing modeling and monitoring of batches in relative time is proposed. Using scores from principal component analysis (PCA) models as a feature space the new methodology is better able to handle the challenges usually experienced in batch analysis. The feasibility of the relative time approach is demonstrated using data from a chemical synthesis and a pharmaceutical drying process.