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Journal articles
The effect of fume on radiative heat transfer in kraft recovery boilers, TAPPI JOURNAL, July 2000, Vol. 83(7)
The effect of fume on radiative heat transfer in kraft recovery boilers, TAPPI JOURNAL, July 2000, Vol. 83(7)
Journal articles
Response of xylanase-treated kraft pulp to escher-wyss and pfi refining, TAPPI JOURNAL, July 2000, Vol. 83(7)
Response of xylanase-treated kraft pulp to escher-wyss and pfi refining, TAPPI JOURNAL, July 2000, Vol. 83(7)
Journal articles
Analysis and characterization of contaminants in occ recycle furnishes, TAPPI JOURNAL, July 2000, Vol. 83(7)
Analysis and characterization of contaminants in occ recycle furnishes, TAPPI JOURNAL, July 2000, Vol. 83(7)
Journal articles
Analysis of pulping data using the self-organizing map, TAPPI JOURNAL, July 2000, Vol. 83(7)
Analysis of pulping data using the self-organizing map, TAPPI JOURNAL, July 2000, Vol. 83(7)
Journal articles
Investing in the future of your mill, TAPPI JOURNAL, July 2000, Vol. 83(7)
Investing in the future of your mill, TAPPI JOURNAL, July 2000, Vol. 83(7)
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
Magazine articles
Optimizing OCC refining with defloccing, TAPPI Journal April 2025
ABSTRACT: Subjecting pulp to a high shear zone immediately after refining results in more efficient refining. This phenomenon was originally observed to benefit softwood pulp refining. It was attributed to floc reduction based on floc measurements in mill refiners and the observation of reduced headbox plugging. Hence, this phenomenon has been termed “defloccing.” The present work shows this technology also benefits refining of North American old corrugated containers (OCC). The combined results of several mill trials with OCC defloccing demonstrate the interactions between OCC refining intensity, defloccing technology, and other state-of-the-art refining improvements. At the same refining intensity, defloccing OCC on 100% recycled machines increases OCC refining efficiency by 15%, with greater efficiency improvement on machines that use softwood as well as OCC. Furthermore, it is shown that the benefits of defloccing are additive to refining improvements made in the refining zone of a refiner plate. Most OCC refiner plate designs can therefore benefit from the addition of a defloccing feature.
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.
Journal articles
Magazine articles
Effects of different soda loss measurement techniques on brownstock quality, TAPPI Journal July 2024
ABSTRACT: The efficiency of the kraft recovery plant, bleaching process, and paper machine are affected when black liquor carryover from the brownstock washers is not controlled well. Measuring soda loss within a mill can vary from using conductivity, either in-situ or with a lab sample of black liquor filtrate squeezed from the last stage washer, to measuring absolute sodium content with a lab sodium specific ion probe or spectrophotometer. While measuring conductivity has value in tracking trends in black liquor losses, it is not an acceptable method in reporting losses in absolute units, typically in lb/ton of pulp. This is further complicated when trying to benchmark soda loss performance across a fleet of mills with multiple washer lines. Not only do the testing methods vary, but the amount of bound soda on high kappa pulps can be significant. This variability creates inconsistent results, and studies are needed to understand the effect of different testing methods on the pulp quality. In this study, soda loss is expressed as sodium sulfate (Na2SO4). Four different methods to measure soda content in pulp off commercial brownstock washers were studied: full digestion (FD), washing soaking overnight and washing (WSW), soaking in boiling water and stirring 10-min (SW-10), and squeeze-no wash (Sq). Total, washable, and bound sodium sulfate calculations were determined for each soda content measuring technique using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results showed bound and washable sodium sulfate amounts significantly depend on which soda measurement technique was used. In addition, the soda results were correlated with the pulp kappa numbers. As the kappa number increases, bound soda increases, regardless of the soda measurement method used. Impacts of high sodium sulfate in brownstock are also discussed.
Journal articles
Extended usage of xylanase enzyme to enhance the bleaching of softwood kraft pulp, TAPPI JOURNAL, January 2006
Extended usage of xylanase enzyme to enhance the bleaching of softwood kraft pulp, TAPPI JOURNAL, January 2006, Vol. 5(1) (164 KB)