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Fate of phosphorus in the recovery cycle of the kraft pulping process, TAPPI Journal March 2020
ABSTRACT: The accumulation of nonprocess elements in the recovery cycle is a common problem for kraft pulp mills trying to reduce their water closure or to utilize biofuels in their lime kiln. Nonprocess elements such as magnesium (Mg), manganese (Mn), silicon (Si), aluminum (Al), and phosphorus (P) enter the recovery cycle via wood, make-up chemicals, lime rock, biofuels, and process water. The main purge point for these elements is green liquor dregs and lime mud. If not purged, these elements can cause operational problems for the mill. Phosphorus reacts with calcium oxide (CaO) in the lime during slaking; as a result, part of the lime is unavailable for slaking reactions. The first part of this project, through laboratory work, identified rhenanite (NaCa(PO4)) as the form of P in the lime cycle and showed the negative effect of P on the availability of the lime. The second part of this project involved field studies and performing a mass balance for P at a Canadian kraft pulp mill.
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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.
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Influence of pallet pattern on top-to-bottom compression performance of unitized loads, TAPPI Journal November 2021
ABSTRACT: Environmental scaling factors estimate a corrugated container’s ability to withstand various conditions it will encounter during the storage and distribution process. In this project, we examined the compressive resistance of unitized loads using differing pallet stacking patterns. To simulate real-world failure scenarios in our laboratory tests, we used two different nominal board grades of single-wall C-flute regular slotted containers loaded with a plywood panel and bagged salt to direct the failure location to the bottom of the stack. Our results showed that the columnar aligned pattern provided the greatest compressive resistance and the interlocked stacking arrangement yielded the lowest of the patterns evaluated. Based on the study results, we calculated box compression retention multipliers for each pattern and compared them to scaling factors published by the Fibre Box Association.
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Comparing a linear transfer function-noise model and a neural network to model boiler bank fouling in a kraft recovery boiler, TAPPI Journal, July 2024
ABSTRACT: Boiler bank fouling reduces heat transfer efficiency in kraft recovery boilers. Here, we model the relationships between boiler parameters and boiler bank pressure drop, an indicator of fouling, based on recovery boiler operating data. We compared two models: an autoregressive integrated exogenous (ARIX) model and a feedforward neural network. The ARIX model better simulates boiler bank pressure drop compared to the neural network (R2 of 0.64 vs. 0.58). Based on the ARIX model, we identified six boiler parameters that significantly influence boiler bank fouling and their relative contributions. Finally, we demonstrate how the models can simulate boiler bank pressure drop given artificial perturbations in boiler parameters.
Journal articles
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Rheological behavior of magnetic pulp fiber suspensions, TAPPI Journal June 2021
ABSTRACT: This paper is focused on the rheology of magnetic pulp suspensions in absence and presence of an external magnetic field. Magnetic fibers were prepared by the lumen loading method using bleached eucalyptus fibers and cobalt ferrite (CoFe2O4) nanoparticles. The effect of mass consistency, temperature, concentration of magnetic fibers, and magnetic field strength on yield stress and apparent viscosity of the suspensions were investigated. In the absence of an applied field, a dependence of yield stress with consistency, as well as with the percentage of magnetic fibers present in the suspension, was found. In flow tests, all the suspensions exhibited shear-thinning behavior, showing that the viscosity is only affected by the consistency of the suspension. On the other hand, magnetorheological measurements show a negative effect of the applied magnetic field on the viscosity of the suspension.
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Effects of lignin chemistry on oxygen delignification performance, TAPPI JOURNAL July 2018
Effects of lignin chemistry on oxygen delignification performance, TAPPI JOURNAL July 2018
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Effect of ring formation on burner flame stability in lime kilns, TAPPI JOURNAL May 2018
Effect of ring formation on burner flame stability in lime kilns, TAPPI JOURNAL May 2018
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Improving the inkjet codability of folding boxboard, TAPPI Journal February 2019
Improving the inkjet codability of folding boxboard, TAPPI Journal February 2019
Journal articles
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Measurement of the dynamics of fluid sorption for tissue papers, TAPPI Journal July 2019
ABSTRACT: Liquid absorption ability belongs to the most important features of tissue papers. Due to non-homo-geneous internal and superficial structures, precise and fast evaluation of this property is challenging. The main aim of the presented research was to design an experimental device dedicated to the measurement of the kinetics of wetting phenomenon for tissue papers. The second aim was to evaluate whether it was possible to use image analysis for more precise characterization of liquid absorption properties of tissue paper. The obtained results showed that the method used, based on image analysis supported by gravimetric methods, proved to efficiently and quantitatively characterize the dynamics of liquid absorption for tissue papers. Supplementary parameters such as absorption anisotropy and in-plane velocity were obtained. Different experi-mental results were obtained for various tissue paper grades. Furthermore, water absorption capacity calculated from image analysis data correlated with results obtained according to the standard method EN ISO 12625-8:2010 “Tissue paper and tissue products—Part 8: Water-absorption time and water-absorption capacity, basket-immersion test method.” Hence, the presented device quantitatively characterizes and discriminates water absorption phenom-enon for tissue papers.
Journal articles
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The Chinese ban on recovered paper imports
The Chinese ban on recovered paper imports: An international disruption, TAPPI JOURNAL November 2017