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Magazine articles
Editor's Note: Collecting industry information that counts,
Editor's Note: Collecting industry information that counts, TAPPI JOURNAL April 2010
Magazine articles
Editor's Note: Monstrous marvels, TAPPI JOURNAL September 20
Editor's Note: Monstrous marvels, TAPPI JOURNAL September 2010
Journal articles
Magazine articles
A hundred years of corrosion in the pulp and paper industry, TAPPI JOURNAL May 2018
A hundred years of corrosion in the pulp and paper industry, TAPPI JOURNAL May 2018
Journal articles
Magazine articles
Editorial: 2018 TAPPI Journal features diverse content, TAPPI Journal November 2018
Editorial: 2018 TAPPI Journal features diverse content, TAPPI Journal November 2018
Journal articles
Magazine articles
Understanding the risks and rewards of using 50% vs. 10% strength peroxide in pulp bleach plants, TAPPI Journal November 2018
Authors: Alan W. Rudie and Peter W. Hart | ABSTRACT: The use of 50% concentration and 10% concentration hydrogen peroxide were evaluated for chemical and mechanical pulp bleach plants at storage and at point of use. Several dangerous occurrences have been documented when the supply of 50% peroxide going into the pulping process was not stopped during a process failure. Startup conditions and leaking block valves during maintenance outages have also contributed to explosions. Although hazardous events have occurred, 50% peroxide can be stored safely with proper precautions and engineering controls. For point of use in a chemical bleach plant, it is recommended to dilute the peroxide to 10% prior to application, because risk does not outweigh the benefit. For point of use in a mechanical bleach plant, it is recommended to use 50% peroxide going into a bleach liquor mixing system that includes the other chemicals used to maintain the brightening reaction rate. When 50% peroxide is used, it is critical that proper engineering controls are used to mitigate any risks.
Journal articles
Magazine articles
Using multistage models to evaluate how pulp washing after the first extraction stage impacts elemental chlorine-free bleach demand, TAPPI Journal November 2018
Using multistage models to evaluate how pulp washing after the first extraction stage impacts elemental chlorine-free bleach demand, TAPPI Journal November 2018
Journal articles
Magazine articles
Laboratory method for determining the source of brightness loss at a southern United States bleached paperboard mill, TAPPI Journal October 2018
Laboratory method for determining the source of brightness loss at a southern United States bleached paperboard mill, TAPPI Journal October 2018
Magazine articles
Guest Editorial: Paul Wiegand: Environmental expert, TAPPI J
Guest Editorial: Paul Wiegand: Environmental expert, TAPPI JOURNAL August 2012
Journal articles
Magazine articles
Influence of tensile straining and fibril angle on the stiffness and strength of previously dried kraft pulp fibers, TAPPI JOURNAL July 2018
Influence of tensile straining and fibril angle on the stiffness and strength of previously dried kraft pulp fibers, TAPPI JOURNAL July 2018
Journal articles
Magazine articles
Numerical analysis of the impact of rotor and screen hole plate design on the performance of a vertical pulper, TAPPI Journal April 2025
ABSTRACT: The dissolving of mechanical pulp is one of the most important process steps in stock preparation, since pulping occurs at the very beginning of the papermaking process. Efficient mixing of the pulp in a short amount of time is essential to achieve high furnish volume flow rates. The design of the rotor, as well as the pulper vat and inserts, significantly affects the overall performance of the pulper, such as mixing efficiency and power demand. Using advanced numerical methods such as computational fluid dynamics (CFD) can accelerate the development process. The CFD simulations allow for detailed analysis of flow phenomena, making it possible to study a real-size machine numerically. This approach is particularly advantageous because it can reduce the need for timeconsuming and costly experiments associated with scaling up test rigs. In this study, we compared two different rotor designs utilized in a vertical pulper and evaluated the numerical results with experimental data. Rotor A is designed for low turbulence and low power demand, while rotor B is designed for high turbulence with high power demand. The CFD results showed good agreement with the experimental measurements. We investigated how the rotor design influences the free fluid surface and the mixing efficiency. Our study also highlights the differences in results depending on whether water or furnish is simulated, which exhibit Newtonian or, respectively, non-Newtonian fluid behavior. Additionally, a detailed numerical investigation of various screen hole plate designs revealed that the newly developed hole design significantly reduces pressure loss compared to a standard drilled hole. This outcome was consistent for both types of fluids investigated: water and furnish.