The effect of process design on refiner pulp quality control performance
Journal article, 2021

In this study, the effect of process- and online analyser configuration on pulp quality control is explored. The following parameters were included: analyser sampling interval, time delay, measurement error magnitude, and latency chest residence time. Using different values of parameters in a process model, a range of configurations were constructed. For each configuration, the achievable control performance was evaluated using an optimization approach. PI controller settings were chosen based on minimization of the integrated absolute error (IAE) in pulp quality after an input step disturbance. The results show that reducing the sampling interval improves performance also when the interval is smaller than the chest residence time or the analyser delay. Moreover, reducing the chest residence time can reduce the IAE by up to 40 %. However, reducing the residence time to lower than 1/3 of the sampling interval does not improve performance. Further improvement is possible if the analyser delay is reduced. The compromise between reducing the IAE and avoiding creating variation by acting on measurement error has a strong influence on the results. In conclusion, pulp quality control performance can be improved significantly by making changes to the studied configuration parameters.

measurement error

optimization

latency chest

mechanical pulp

sampling rate

Author

Johan Sund

Mid Sweden University

Holmen Paper AB

C. Sandberg

Holmen Paper AB

Mid Sweden University

Anders Karlström

Chalmers, Electrical Engineering

Göran Thungström

Mid Sweden University

P. Engstrand

Mid Sweden University

Nordic Pulp and Paper Research Journal

0283-2631 (ISSN) 2000-0669 (eISSN)

Vol. 36 4 594-607 20210011

Subject Categories

Control Engineering

DOI

10.1515/npprj-2021-0011

More information

Latest update

4/6/2022 5