Friday, May 30
by Mathieu Régnier, Paper Advance
While a panel discussion was taking place on the transfer of knowledge and its applications to the pulp and paper industry (Session 3B with moderator Pam Woyciehouski, Canfor CPL PGI), participants gathered next door for a parallel session on process control headed by Session Chair, for a second year, Francesca Apruzzese of West Frazer in Hinton, Alberta. “This track at PACWEST features some of the industry’s best practices and case studies on process control” she says.

Process control advancements are always of interest to paper manufacturing managers. Automation results from process control but well trained operating personnel are necessary to operate what can sometimes be complex processes. Mastering knowledge around this issue is essential to remain competitive and profitable. Operating our equipment to the absolute highest efficiency possible requires this engineering discipline to evolve along technological and scientific advancements and the presenters discussed means to maintaining outputs and different processes within desired range. Algorithms, mechanisms and different systems infrastructure all allow a consistent product output necessary to answer the ever-going challenge of reliability. Constraints and bottlenecks need to be removed as much as possible in production while maintaining a steady operational flow.

The first presenter is Gary Caswick in replacement of David Eapen, Metso Automation. His paper on the automation of steam network control and optimization first highlights the fact that the majority of steam generated in a typical pulp and paper mill is to support “process”. In a normal scenario, “steam produced is delivered through a network at different pressures to the various steam consumers”. Gary Caswick explains that mills expect steam network controls at a regular quality and availability while maintaining overall energy efficiency but that “consumption or production disturbances can be sudden and large in magnitude and this with very little warning”. As such, traditional steam network controls lack in efficiency and this is where Metso’s “Advanced Process Controls” offers an answer to optimize steam production. Caswick presents results from three projects - two in Finland and one in Brazil. Other Metso papers presented in this session are:
  • “Proper use of Lab, In-Line and On-Line Measurements for Fiberline Monitoring and Control”. James Goldman, Metso Automation.
  • “Fiberline pH Measurement and Controls” Kari Lampela, Metso.
  • “Bleach Plant Control Optimization using InLine Brightness and Residual Measurements along with On-Line Kappa Measurements”. James Goldman, Metso Automation.
Simon Ulenberg, West Fraser-Hinton Pulp and Devin Marshman, Spartan Controls present a paper entitled “Fully Coordinated Pulp Machine MD Controls using MPC”. After an introduction to Model Predictive Control (MPC), an effective means to deal with multivariable constrained control problems that can be traced back to the 1960s, the speakers described how Hinton Pulp implemented a novel approach to Pulp Machine MD controls using MPC. In doing so, “process constraints and regulatory control limitations are accounted for by controlling the multivariable pulp machine process using a multivariable control method, and deadtime compensation is addressed by the predictive nature of control algorithm”. Simon Ulenberg and Devin Marshman present a preliminary comparison of performance before and after MPC implementation. They observe that the project shoehorned into migration path and schedule, that there was an increased ability to maintain and change MD controls and that machine performance has shown overall improvements.

“Performances and Benefits of Fiber Orientation CD Control” is presented by Cristian Gheorge, Honeywell Process Solutions. The paper surveys the performances and benefits of a multivariable model predictive controller for cross directional fiber orientation processes. Results are positive as this control process effectively eliminated troubles with sheet flatness uniformity originating from board machines. The Fiber Orientation CD Control provides simultaneous optimization of “top and bottom layer fiber orientation profiles together with a derived proxy for twist”. Managers present in the room this morning realize that help and expertise abound in the field of industrial control systems. That through this complexity, there is beauty in gathering and transmitting data that is obtained during manufacturing processes.