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An Alternative Method of Assessing Accelerated Stability on Aqueous Biobased Dispersions for Oil and Grease Resistance (OGR) Coatings, TAPPICon 2023

Characterizing rheological behavior and fluidization of highly refined furnishes, TAPPI Journal April 2024

ABSTRACT: In this work, highly refined softwood bleached kraft pulp (SWBKP) furnishes, referred to here as XFC, were studied from the perspective of fiber suspension handling in processing. The rheology of the furnishes was studied with a rotational rheometer using a non-standard flow geometry to understand the viscosity development at different consistencies and the impact of temperature. For fluidization analysis during pipe flow, two optical methods were implemented; namely, optical coherence tomography (OCT) and high-speed video (HSV) imaging. The OCT was used to determine the small-scale floc structures near the pipe wall where the shear stress is highest, and the HSV imaging was applied for observing flow instabilities and XFC suspension uniformity at the pipe scale. All these issues can be significant in deciding the minimum flow rate required for a process pipe to get sufficient fluidization of XFC suspensions.

Numerical analysis of slot die coating of nanocellulosic materials, TAPPI Journal November 2020

ABSTRACT: Nanocellulosic coatings as a food packaging material are of commercial interest due to their nontoxic nature, renewability, and excellent barrier properties. Complex shear-thinning rheology poses challenges in designing and sizing equipment to pump, mix, and process the suspension and actual coating process. This study aims to determine the effectiveness of computational fluid dynamics (CFD) in predicting nanocellulosic suspension flow in light of existing rheological data. We employ and compare three distinct rheological models to characterize the rheology and flow of nanocellulose suspensions through a slot die coater, where the model parame-ters are established from existing slot rheometry measurements. A volume-of-fluid (VoF) based finite volume meth-od is employed to simulate the flow in a slot die operated in an unconventional metering mode. Results with the Casson model predict the presence of unyielded regions in the flow, which was not captured using the power law model. These stagnation regions will incur coatability issues stemming from flow intermittencies and lead to poten-tial defects in the coating layer, including fracture. The results suggest that a rheological model that includes yield stress should be considered while modeling such flows. A need for better rheological data to model nanocellulosic flows, especially at high consistencies and shear rates, is also highlighted.

FEL1 and 2 • The Beginnings of Successful Paper Machine Conversions, 20PEERS Conference

FEL1 and 2 • The Beginnings of Successful Paper Machine Conversions, 20PEERS Conference

How process & mechanical conditions affect lime recovery kiln thrust positions - a review of operations and mechanics for this phenomenon, 20PEERS Conference

How process & mechanical conditions affect lime recovery kiln thrust positions - a review of operations and mechanics for this phenomenon, 20PEERS Conference

Rheological Characteristics of Platy Kaolin, 19PaperCon

Rheological Characteristics of Platy Kaolin, 19PaperCon

Fundamental Understanding of Bound Water Removal in Paper Drying Process: Microscopic Approach, 19PaperCon

Fundamental Understanding of Bound Water Removal in Paper Drying Process: Microscopic Approach, 19PaperCon

Increased Machine Efficiency Using A Novel, Structured Wet Strength Resin, 19PaperCon

Increased Machine Efficiency Using A Novel, Structured Wet Strength Resin, 19PaperCon

High Kappa Process for Eucalyptus Fiberline - The First Industrial Case, 19PEERS

High Kappa Process for Eucalyptus Fiberline - The First Industrial Case, 19PEERS

Soap removal at southern kraft mill using centrifugal separation, 19PEERS

Soap removal at southern kraft mill using centrifugal separation, 19PEERS