Multivariate statistical Procedures for monitoring the progress of bat
ch Processes are developed. The only information needed to exploit the
procedures is a historical database of past successful batches. Multi
way PrinciPal component analysis is used to extract the information in
the multivariate trajectory data by projecting them onto low-dimensio
nal spaces defined by the latent variables or principal components. Th
is leads to simple monitoring charts, consistent with the philosophy o
f statistical process control, which are capable of tracking the progr
ess of new batch runs and detecting the occurrence of observable upset
s. The approach is contrasted with other approaches which use theoreti
cal or knowledge-based models, and its potential is illustrated using
a detailed simulation study of a semibatch reactor for the production
of styrene-butadiene latex.