Nova Scotia’s Port Hawkesbury Paper, a 350,000 metric tonnes per year top quality supercalendered paper mill, enlisted FPInnovations to help develop and improve the performance and profitability of its thermomechanical pulp (TMP) and paper mill operation. Bevan Lock, Pulp Production Manager, explains, “We needed the depth and rigor of a strong R&D group. Under previous mill ownership, FPInnovations provided this solid technical support and working relationship.” With this previous relationship well established, and with the current FPInnovations membership in place since the new ownership in 2012, the mill staff developed a plan with FPInnovations.
The recent projects included energy cost reduction in the TMP mill, a holistic mill-wide energy audit and evaluation project to identify and implement energy-saving projects, and enhanced effluent sludge dewatering to achieve consistently higher solids content and save polymer costs. The total savings from all three successful projects was approximately $1.5 million per year. The return on investment for all projects was less than one year, and the sludge dewatering payback period was less than four months.
All three projects involved great teamwork between FPInnovations and mill staff. Lock comments, “They were a pleasure to work with, communications were strong, and their enthusiasm for the Canadian pulp and paper industry was infectious. They were aligned with our priorities.”
Based on pilot plant studies and detailed fibre analysis provided by FPInnovations, changes were recommended and implemented in the TMP rejects handling process. A major step was permanently eliminating the screening of rejects. The elimination of energy to drive the screen motors and lower reject refiner motor loads resulted in annual savings of $750,000 with no adverse impact on either pulp properties or paper machine runnability.
The energy evaluation project involved a heat and mass balance simulation of the whole mill by FPInnovations. This analysis and implementation led to steam savings in the paper machine wet end and calendering operations totaling $350,000. A follow-up project involving repurposing of existing heat exchangers is expected to provide similar savings.
FPInnovations’ effluent sludge acidification system increased and stabilized the solids content of the dry cake sludge to ensure it was suitable for firing with hog fuel in a biomass boiler which drives a condensing turbine owned by Nova Scotia Power. The polymer dose decreased substantially while the dry cake solids are now consistently above the 30% minimum specified by Nova Scotia Power. This avoids landfill costs, and results in total annual savings of around $360,000.
For more information about this project, please contact Mark Frith.
This article was originally published in the 2016-2017 IMPACT magazine.