Thursday, May 29
by Mathieu Régnier, Paper Advance
While Session 2B on Kraft Pulping and Energy was being held, Session 2A on "Mechanical Pulping and Papermaking” presented six papers under the chairmanship of Dan Davies, Evonik Canada. Davies, an industrial chemist by training, introduced the presenters and their contributions to PACWEST 2014. The session allowed participants to obtain first-hand knowledge on recent experiences and advances in the fields of mechanical pulping and papermaking.

Brian O’Connor, FPInnovations gave an interesting talk centered on Life Cycle Assessment (LCA), an ISO methodology for quantifying environmental impacts of a product or process. LCA is certainly an area of concern to the pulp and paper industry. It concerns the development of new products, receiving waters management, effluent treatment or energy and resource recovery from solid residues. The specific issue of Brian O’Connor’s presentation today was the quantifying of environmental benefits resulting from capital investments at a BCTMP Mill.

Doug Sweet, P.E., Doug Sweet & Associates presented a paper entitled “The Vacuum System Survey – Its Contribution to Papermaking”. An often-misunderstood industrial system is the vacuum system says Doug Sweet. Yet, a better understanding of this subsystem will allow mill managers to take action for continuous improvement efforts. Among other benefits from vacuum system surveys, we note: lower operating horsepower and reduced vacuum pump maintenance. The audience knows how much papermaking consists of many such interrelated subsystems (drying, pressing, forming, wet and chemistry or stock cleaning). The Alabama based consultant explains why the vacuum system suffers from this misunderstanding and why problems with the vacuum system operation impact sheet dewatering and paper machine performance. “Vacuum surveys require much more than calculating vacuum factors for each vacuum element. Every survey will acquire its own objectives and outcomes, as well as focusing on problems uncovered during the survey process. »

Jean-François Hamelin, Process Optimization Engineer, Metso Automation, presents “Benefits of Implementing a Paper Brightness Control System in a 2-machine Newsprint Mill”. Manipulation of chemicals for manual bleaching can be difficult in the context of target changes. Bleaching specialists being perfectionists, over bleaching happens too often. This becomes even more challenging in mills with more than one paper machine. Hamelin discusses the case of a mill with two paper machines that tried to maintain two different targets “using common bleach addition points”. In the case of the described mill, a control application was designed to use « manipulated variables in a multi-variable predictive control (MPC) strategy ». This allows brightness targets to be maintained on different machines and to minimize bleaching agents use thus reducing the environmental footprint of the process. Hamelin describes the next steps in research as finding the best way to « bring targets directly from the production schedule into the MPC controller ». This should ensure that brightening is minimized during grade transitions.

Other presentations from this afternoon’s session include:

“Key Softwood Fibre Attributes for Tissue Making.” Ho Fan Jang, FPInnovations.

“Finding the Not-So Obvious.” Chris Shelley, Controls Engineer, PE, and Business Development Manager, Metso, ExpertTune