Paper Technology International 2024 - Journal - Page 22
PAPERTECHNOLOGYINTERNATIONAL
Case study 2.
Identifying energy-and cost-ef昀椀cient operation
practices
Case Study 3.
Investigating simultaneous issues in the process
Often, there might be differences in operational routines
and ways of running the paper machine between operator shifts,
developed over time. With the help of Harmonizer, these differences
can be revealed and the most ef昀椀cient operational practices, e.g.
by experienced operators, can be identi昀椀ed and implemented for
broader use.
In this case, the harmony models made visible the varying
ways of utilizing additional heat unit that was used to secure
adequate water removal at a board machine. With measurements
from water removal and heat utilization, the tool revealed an
occasional disharmony that happened immediately after grade
changes [昀椀gure 3]. The 昀椀ndings indicated that the operational
guidelines were not optimal for each produced grade at the mill.
Before the grade change, the measured (black line) and
harmony levels (blue line) were at the same level, indicating that
water removal, heat unit, and other related process parameters
were in balance. After the grade change, the measurement drops
and deviates signi昀椀cantly from the harmony level, revealing that the
water removal is no longer suf昀椀cient. After a few control adjustments
by the operators (showing as level changes in the black line), the
harmony is restored. On other occasions, the insights from the
model indicated the opposite: that the additional heat was not
needed after the grade change to reach the desired water removal.
Process engineers made a deeper analysis of the
phenomena and discovered that these types of deviations repeated,
especially with lighter grammages. They also recognized that the
reduced temperature in the heat unit – as regularly applied by a
particular operator – did not negatively impact product quality. With
this new data and evidence, they could make new grade-speci昀椀c
guidelines on the use of the additional heat unit, optimizing energy
consumption and leading to signi昀椀cant energy savings.
Harmony models can extract simultaneous changes in
the process parameters and highlight them for the operators and
engineers at the mill. This helps make interdependencies in the
process visible and visualizes how deviations escalate in production.
In this case, Harmonizer revealed several simultaneous
problems that started to develop in the papermaking system
following a production break (昀椀gure 4). First, the pH in the machine
chest and fresh water increased, causing a harmony deviation.
When the fresh water pH was then reduced, it immediately impacted
the whole system, including the vacuums in the forming section.
This example shows well how the harmony model can combine
different tags from different parts of the process, revealing previously
unknown interdependencies.
With this insight into the simultaneous problems in different
machine positions, operators and engineers can take more informed
corrective and preventive measures. The bene昀椀t of the holistic view
is that the user does not just see one measurement that is off from
its intended value but can also investigate its impact in the process.
Empowering operators
The essence of the papermaking process is in constant
change. The 昀氀uctuating quality of the main raw materials – woodbased 昀椀bers and water – also impacts how the paper machine runs.
The countless interdependencies, delays, and spillover effects in the
long, continuous process all cause unpredictability.
Process harmony is the key to unlocking the next level
of production ef昀椀ciency. With automated machine learning and
harmony modeling, KemConnect Harmonizer creates unique
transparency in the multifaceted papermaking environment. It
provides a comprehensive view of the stability of the papermaking
system as a whole. These insights and visibility are a powerful tool
that enables the process experts, the operators and engineers at
Figure 3: Disharmony revealed by the harmony models in the utilization of additional heat after a grade change.
Figure 4: The harmony model revealed multiple simultaneous issues in the papermaking systems following an issue with fresh
water pH.
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