Schemes for monitoring the operating performance of large continuous processes
using multivariate statistical projection methods such as principal component anal-
ysis ( PCA ) and projection to latent structures ( PLS ) are extended to situations
where the processes can be naturally blocked into subsections. The multiblock pro-
jection methods allow one t o establish monitoring charts f o r the individual process
subsections as well as for the entire process. When a special event or faul t occurs
in a subsection of the process, these multiblock methods can generally detect the
event earlier and reveal the subsection within which the event has occurred. More
detailed diagnostic methods based on interrogating the underlying PCA / PLS models
are also developed. These methods show those process variables which are the main
contributors to any deviations that have occurred, thereby allowing one to diagnose
the cause of the event more easily. These ideas are demonstrated using detailed
simulation studies on a multisection tubular reactor for the production of low-density polyethylene.