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Journal articles
The influence of formation on tensile strength of paper made from mechanical pulps, TAPPI JOURNAL, December 2000, Vol. 83(12)
The influence of formation on tensile strength of paper made from mechanical pulps, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Wood quality ranking of plantation trees, TAPPI JOURNAL, December 2000, Vol. 83(12)
Wood quality ranking of plantation trees, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Presentation of a dry black liquor gasification process with direct causticization, TAPPI Journal March 2006
Presentation of a dry black liquor gasification process with direct causticization, TAPPI Journal March 2006
Journal articles
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, Novem
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, November, 2006
Journal articles
Parameters Affecting the Supercalender's Ability to Keep Up
Parameters Affecting the Supercalender's Ability to Keep Up with the Machine, 1990 Finishing and Converting Conference Proceedings
Journal articles
Integrated Automatic Storage and Retrieval in a Fine Papers
Integrated Automatic Storage and Retrieval in a Fine Papers Finishing Department, 1991 Finishing and Converting Conference Proceedings
Journal articles
The Power of Teams: Improving Quality in the Paper Industry
The Power of Teams: Improving Quality in the Paper Industry by Involving People, 1993 Finishing and Converting Conference Proceedings
Journal articles
Magazine articles
Continuous digester process safety improvements • Stress corrosion cracking and overpressure protection lessons learned and opportunities, TAPPI Journal October 2024
ABSTRACT: Georgia-Pacific has recent experience with continuous digester stress corrosion cracking (SCC) repairs where the extent of SCC was more than previous spot inspections had predicted (one digester had anodic protection, one did not). This paper offers case studies of reviewed and improved digester inspections by use of “boat” samples to quantify the depth of cracking mechanism. Boat sample test data is used to support repair recommendations based on hardness testing. Georgia-Pacific also reviewed overpressure protection systems and corrected gaps found in these systems. These included updating to the latest original equipment manufacturer (OEM) designs and formalizing functional testing procedures and practices. This review of digester inspection, testing, and repairs since 2020 provides: (1) a basis for including a 3rd party corrosion expert to be a part of inspections; (2) removes the use of power-wire brushes; (3) enhances digester inspection with 100% phased-array ultrasonic testing to detect SCC; and (4) ensures overpressure protection design and testing is aligned with corporate needs and the site-specific challenges.
Journal articles
Magazine articles
Editorial: Concentrated content: TAPPI Journal special issues create research visibility, TAPPI Journal September 2024
You may have noticed that TAPPI Journal often brings readers special focused issues from time to time. Over the years, these issues have covered a range of topics, including wet-end technology, recovery cycle, foam forming, coating, additives, biorefinery, nanotechnology, lignin, pulping, recycling, university research, and more.
Journal articles
Magazine articles
Control of continuous digester kappa number using generalized model predictive control, TAPPI Journal September 2024
ABSTRACT: Kappa number variability at the digester impacts pulp yield, physical strength properties, and lignin content for downstream delignification processing. Regulation of the digester kappa number is therefore of great importance to the pulp and paper industry. In this work, an industrial application of model-based predictive control (MPC), based on generalized prediction control, was developed for kappa number feedback control and applied to a dual vessel continuous digester located in Western Canada. The problem was complicated by the need to apply heat at multiple locations in the cook. In this study, the problem was reduced from a multiple to a single input system by identifying three potential single variable permutations for temperature adjustment. In the end, a coordinated approach to the heaters was adopted. The process was perturbed and modeled as a simple first order plus dead time model and implemented in generalized predictive control (GPC). The GPC was then configured to be equivalent to Dahlin’s controller, which reduced tuning parameterization to a single closed loop time constant. The controller was then tuned based on robustness towards a worst-case dead time mismatch of 50%. The control held the mean value of the kappa number close to the setpoint, and a 40% reduction in the kappa number’s standard deviation was achieved. Different kappa number trials were run, and the average fiberline yield for each period was evaluated. Trial results suggested yield gains of 0.3%•0.5% were possible for each 1 kappa number target increase.