The catalytic naphtha reforming process
is one of the most significant
processes in the petrochemical industry. This process is notable for
its function of transforming petroleum refinery naphtha from crude
oil with low octane ratings into high-octane premium blending stocks,
namely, gasoline or aromatic hydrocarbons. This process consists of
many units along with complicated chemical reactions, which leads
to large-scale and strong coupling, with time variation and nonlinearity
to some extent. Under such circumstances, it remains a great challenge
to control and optimize the catalytic reforming process. To evaluate
the current operational status of the catalytic reforming process,
there is a need for online assessment of some key quality-related
indices for engineers as a reference. Among these indices, research
octane number (RON) barrel is widely used for the evaluation of gasoline
quality. However, traditional measurement methods are often time-consuming,
labor-consuming, and expensive. To overcome such drawbacks, a data-driven
predictive model for the prediction of RON barrel values is proposed
in this study. Considering data from real industry are often contaminated
with noise and other uncertain factors, conventional data-driven prediction
methods may fail in the extraction of useful process information.
Meanwhile, missing data is also commonly observed in real industrial
samples. To deal with these problems, the proposed predictive model
employs a semisupervised learning-based just-in-time learning framework.
Different from traditional just-in-time learning frameworks, variable
selection is taken into consideration in the proposed framework, in
addition to sample selection. And both selection approaches proceed
on the basis of the symmetric Kullback–Leibler divergence,
which measures the distributional dissimilarities among samples or
variables, to reduce the noise influence. Additionally, variational
Bayesian principal component analysis, which is known as an effective
generative model, is exploited to alleviate the missing data problem.
Eventually, a novel nonlinear slow feature analysis algorithm, namely,
locally weighted slow feature analysis, is put forward to model the
time variance and nonlinearity of this process. To better validate
the efficiency and superiority of the proposed method, an industrial
case study is conducted with data collected from a real industrial
catalytic reforming process, where missing data percentage ranges
from 0.1 to 10%. The qualitative and quantitative results demonstrate
that the proposed technique can outperform some conventional data-driven
methods.