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Journal articles
Preparation and characterization of bioactive and breathable
Preparation and characterization of bioactive and breathable polyvinyl alcohol nanowebs using a combinational approach, October 2016 TAPPI JOURNAL
Journal articles
Magazine articles
Prediction of box failure from paper data for asymmetric corrugated board, TAPPI JOURNAL August 2018
Prediction of box failure from paper data for asymmetric corrugated board, TAPPI JOURNAL August 2018
Journal articles
Magazine articles
Impact of fiber structure on edge-wicking of highly-sized paperboard, TAPPI JOURNAL August 2018
Impact of fiber structure on edge-wicking of highly-sized paperboard, TAPPI JOURNAL August 2018
Journal articles
Bleaching optimization at WestRock mill in Covington, Virgi
Bleaching optimization at WestRock mill in Covington, Virginia, TAPPI JOURNAL September 2016
Journal articles
Magazine articles
Mill experience of calcium carbonate scale formation in green liquor pipelines, TAPPI Journal August 2020
ABSTRACT: Experience of hard calcite (CaCO3) scale formation in green liquor pipelines at four kraft pulp mills was systematically investigated to determine if there is any correlation between the severity of the scaling problem at each mill and the design and operating conditions of its causticizing plant. The results show that the high degree of supersaturation of calcium ions (Ca2+) in the liquor is the main contributing factor. Mills that operate at a lower green liquor total titratable alkali (TTA), higher causticity, and a larger liquor temperature drop are more likely to produce a green liquor that is supersaturated with Ca2+, and thus experience more severe scaling problems. In order to minimize CaCO3 scaling, the green liquor handling equipment should be operated as steady as possible to avoid conditions that allow Ca2+ to be supersaturated. The strategies include minimizing variations in liquor TTA, insulating the green liquor pipelines to reduce temperature gradients, and adding lime mud to weak wash to provide seeds for precipitation to occur on mud particles instead of on metal substrate.
Journal articles
Magazine articles
A new approach for the preparation of cellulose nanocrystals from bamboo pulp through extremely low acid hydrolysis, TAPPI Journal January 2020
ABSTRACT: As a renewable and biodegradable nanomaterial, cellulose nanocrystal (CNC) has a wide range of potential applications, but production of CNC faces significant challenges in capital investment and manufacturing cost. In this work, the one-step preparation of CNC from bleached kraft bamboo pulp by extremely low acid (concen-tration of acid = 0.1 wt%) hydrolysis was demonstrated. The experimental data indicated that the yield of CNC was strongly affected by the operating pressure and concentration of hydrochloric acid (HCl), as well as temperature. Rod-like CNC with a mean particle size of 524 nm was obtained through an extremely low acid (ELA) hydrolysis pro-cess. The yield of CNC can reach to 37.1% by an ELA hydrolysis process at 180°C for 60 min with 0.08 wt% HCl and 20 MPa operating pressure. The Fourier transform-infrared spectroscopy (FTIR) measurements show that the as-pre-pared CNC maintained cellulose structure. Compared with a conventional CNC prepared by strong sulfuric acid (H2SO4) hydrolysis, the CNC prepared by ELA hydrolysis process exhibited much higher thermal stability.
Journal articles
Magazine articles
Root cause analysis of cationic polymer additive efficiency decline in virgin and recycle containerboard mills, TAPPI Journal January 2020
ABSTRACT: It is well known that retention, drainage and strength polymers struggle to perform (if at all) in virgin containerboard mills. In-depth studies have been undertaken in this area for more than seven years, investigating the issue from all directions. A key finding of this work is that soluble lignin is detrimental to chemical efficiency. A strong correlation exists between decreased chemical efficiency and high soluble lignin. Both recycled systems and virgin systems have been studied, and this correlation holds true regardless of furnish. The primary area of concern is virgin container-board, because these mills tend to have the highest lignin levels. Some highly closed recycled mills can also build elevated lignin levels that can negatively affect chemical efficiency.
Journal articles
Magazine articles
Effects of varying total titratable alkali and causticizing efficiency targets on kraft pulp mill productivity, TAPPI Journal March 2024
ABSTRACT: The kraft mill causticizing area is often overlooked and undervalued when it comes to mill optimization; however, the operation of the causticizing plant has downstream effects on the entire liquor cycle. Setting the right targets for the causticizing plant can have a tremendous effect on mill operating costs, as well as push the production bottleneck from one unit operation to another. The key performance parameters associated with the causticizing plant itself are liquor total titratable alkali (TTA) and causticizing efficiency. Individual facilities choose their TTA and causticizing efficiency targets based on their goals, the limits of their equipment, and past experiences. This gives a variety of operating strategies in practice, but what are the implications for optimizing total titratable alkali and causticizing efficiency, and what level of optimization can be achieved through implementation of modern technology? This paper reviews the results of several different operational strategies and models the effects of these different approaches on kraft mill liquor cycle.
Journal articles
Magazine articles
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.
Journal articles
Magazine articles
The use of hollow sphere pigments as strength additives in paper and paperboard coatings—Part 2: Optimization in paperboard formulations for opacity and strength, TAPPI Journal November 2020
ABSTRACT: This report aims to summarize the efforts in testing the properties of coatings for paperboard utilizing hollow sphere pigments (HSPs). HSPs are known to effectively scatter light and replace titanium dioxide (TiO2) in architectural coating formulations. The effect of the particle size and void fraction was evaluated, along with many coating parameters, including level of addition, binder chemistry, and blends of two HSPs. The small HSPs that have optimized voids for scattering light showed equivalent strength to the TiO2-containing control. The strength data was surprising, particularly the improvement in strength for coatings containing large particle size HSPs. Because of this increase in strength, four parts of binder could be removed, which allowed for higher brightness while not compromising other properties, including hot melt glueability. These trends held true using different binder chemistries (styrene acrylic, vinyl acrylic, and styrene butadiene). Upon refining the formulations further, blends of two HSPs showed further benefit.