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Journal articles
Magazine articles
The Paper360° 2022 TOP 50 POWER LIST, Paper360º July/August 2022

Journal articles
Magazine articles
Open Access
Effects of rings on flow and temperature in lime kilns, TAPPI Journal June 2022

ABSTRACT: A steady state, two-dimensional (2D) axisymmetric model has been developed to help understand how rings form and grow in a typical lime kiln. Rings of varying length, thickness, and geometry at the front and back faces were modeled to study the effects on flue gas flow and temperature. The results show that ring growth causes the gas velocity to increase and insulates the adjacent refractory, resulting in a lower kiln shell temperature. The results also reveal the formation of recirculation zones immediately down-stream of the rings, as well as temperature deviations upstream and downstream of the rings that might promote recarbonation and further ring growth. The model was applied to a kiln from a kraft mill with front-end and mid-kiln rings and good agreement was obtained between the measured and predicted kiln shell temperatures, providing confidence in the modeling.

Journal articles
Magazine articles
Open Access
The Influence of the Fine Structure of Cellulose on the Action of Cellulases, TAPPI Journal June 2022

ABSTRACT: In the hydrolysis of cellulose with enzymes of Aspergillus niger at 47°C., it shown that a great decrease in the rate occurred in the late stage of the reaction, usually with considerable cellulose still reamaining undissolved.

Journal articles
Magazine articles
Efficiency is Key for High Capacities, Paper360º March/April 2022

Efficiency is Key for High Capacities, Paper360º March/April 2022

Journal articles
Magazine articles
Open Access
Web instability in the open draw and the impact on paper machine efficiency, TAPPI Journal May 2022

ABSTRACT: Paper is most likely to break in the first open draw on a paper machine where it is unsupported, wettest, and weakest. Tension is applied to peel the web from the roll surface, as well as minimize web flutter in the open draw. The average tension is well below the breaking point and is often set by adjusting the speed difference between the press and the next machine element by visually observing the behavior of the web. However, machine direction variations caused by instabilities in the paper machine can cause tension swings that exceed the strength of the web. Measurement of the web’s release point from press rolls on pilot and commercial paper machines was used to identify the cause of tension instabilities. Variations in the speed of the paper machine drives and the work of adhesion from the press roll surface were identified as key factors. Fluctuations of paper moisture, which affects the elastic modulus and strength of the web, appear to be less important.

Journal articles
Magazine articles
TAPPI Journal Summaries, Paper360º November/December 2022

Journal articles
Magazine articles
Open Access
How do mud balls form in lime kilns?, TAPPI Journal April 2023

ABSTRACT: Mud ball formation in lime kilns has been a persistent problem in many kraft mills, particularly for older kilns that are equipped with chains. A systematic laboratory study was conducted to examine how mud balls are formed and the key factors that affect ball formation. The results confirm the general mill experience that high moisture and high sodium contents in lime mud are the main contributing factors to ball formation. The high moisture content allows lime mud to agglomerate and grow to form balls, while the high sodium content helps make the balls hard and retain their shape. A ball formation mechanism is proposed to explain how mud balls form and grow near the kiln feed end.