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Multivariate statistical process monitoring of batch‐to‐batch startups
Author(s) -
Yan Zhengbing,
Huang BiLing,
Yao Yuan
Publication year - 2015
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.14939
Subject(s) - hilbert–huang transform , batch processing , process (computing) , nonparametric statistics , trajectory , multivariate statistics , decomposition , computer science , signal (programming language) , variable (mathematics) , series (stratigraphy) , statistical process control , mathematics , algorithm , statistics , chemistry , mathematical analysis , paleontology , physics , organic chemistry , white noise , astronomy , biology , programming language , operating system
In batch processes, multivariate statistical process monitoring (MSPM) plays an important role for ensuring process safety. However, despite many methods proposed, few of them can be applied to batch‐to‐batch startups. The reason is that, during the startup stage, process data are usually nonstationary and nonidentically distributed from batch to batch. In this article, the trajectory signal of each process variable is decomposed into a series of components corresponding to different frequencies, by adopting a nonparametric signal decomposition technique named ensemble empirical mode decomposition. Then, through instantaneous frequency calculation, these components can be divided into two groups. The first group reflects the long‐term trend between batches, which extracts the batch‐wise nonstationary drift information. The second group corresponds to the short‐term intrabatch variations. The variable trajectory signals reconstructed from the latter fulfills the requirements of conventional MSPM. The feasibility of the proposed method is illustrated using an injection molding process. © 2015 American Institute of Chemical Engineers AIChE J , 61: 3719–3727, 2015