Double Moving Window MPCA for Online Adaptive Batch Monitoring

Online monitoring of chemical process performance is extremely important to ensure the safety of a chemical plant and consistently high quality of products.Multivariate statistical process control has found wide applications in process performance analysis,monitoring and fault diagnosis using existing rich historical database. In this paper,we propose a simple and straight forward multivariate statistical modeling based on a moving window MPCA(multiway principal component analysis)model along the time and batch axis for adaptive monitoring the progress of batch processes in real-time.It is an extension to minimum window MPCA and traditional MPCA. The moving window MPCA along the batch axis can copy seamlessly with variable run length and does not need to estimate any deviations of the ongoing batch from the average trajectories.It replaces an invariant fixed-model monitoring approach with adaptive updating model data structure within batch-to-batch,which overcomes the changing operation condition and slows time-varying behaviors of industrial processes.The software based on moving window MPCA has been successfully applied to the industrial polymerization reactor of polyvinyl chloride (PVC)process in the Jinxi Chemical Company of Chins since 1999.