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SetPoint: Follow the Leaders, Paper360º May/June 2017
SetPoint: Follow the Leaders, Paper360º May/June 2017
Journal articles
Magazine articles
Suppliers Reach Out to Mill Leaders, Paper360º May/June 2017
Suppliers Reach Out to Mill Leaders, Paper360º May/June 2017
Journal articles
Magazine articles
Tissue Industry News, Tissue360º Spring/Summer 2014
Tissue Industry News, Tissue360º Spring/Summer 2014
Journal articles
Magazine articles
ST Tissue Producing 310-in Semi-Creped Parent Reels on Reco
ST Tissue Producing 310-in Semi-Creped Parent Reels on Reconfigured UFS Machine in Virginia, Tissue360º Fall/Winter 2013
Journal articles
Magazine articles
Over the Wire Tissue Edition, Tissue360º Fall/Winter 2013
Over the Wire Tissue Edition, Tissue360º Fall/Winter 2013
Journal articles
Magazine articles
Continuous tannin extraction by use of screw reactor, TAPPI Journal February 2021
ABSTRACT: A pilot-size screw reactor (extraction unit) was used for tannin extraction of spruce. Yield of the same magnitude or better was obtained when comparing a screw reactor with batch reactors. A longer presoaking time in water seemed to be better than a short one for obtaining higher yield. A higher yield is obtained with lower dry-water ratio, which suggests that the internal diffusion in bark does not determine mass transfer as much as is the case without presoaking of bark. The higher dry-water ratio decreased the yield. The prior soaking of the bark also minimized the mechanical reactor feeding problems (clogging). The benefits of a screw reactor likely are that run time changes for different process conditions are flexible; it simplifies design and construction of an industrial unit for tannin production; and it saves space because of the need for fewer and smaller intermediate storage tanks.
Journal articles
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Key material properties in crease cracking of kraft paper, TAPPI Journal February 2021
ABSTRACT: Crease cracking of paperboard is important to control for the appearance and structural integrity of packages. Crease cracking is affected by creasing operation variables, as well as the physical properties of the paperboard. However, the effects of the physical properties are not clearly known. The objectives of this work were to identify the key material properties that affect crease cracking and to clarify the effects of fiber composition and starch. Laboratory sheets were produced from bleached and refined softwood and hardwood commercial pulp at grammage and thicknesses that match a typical paperboard. To mimic papermaking operations, surface starch was applied via a bench-top size press. The sheets were creased in the lab over a range of penetration depths, and reverse-side cracking was measured. The results showed that less reverse-side cracking was correlated with higher tensile post-peak energy, a lower bending stress, and a lower z-direction (ZD) stiffness. The tensile post-peak energy is a measure of the resistance to crack growth via fiber-bridging. The bending force and the ZD stiffness influence the forces that create cracks. It was observed that decreasing the ratio of hard-wood-to-softwood content and reducing the amount of starch would both decrease crease cracking.
Journal articles
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Application of foamed additives to the surface of wet handsheets, TAPPI Journal January 2021
ABSTRACT: We explored the application of foamed wet-end additives onto wet handsheets to qualify our method of application and to demonstrate the method’s usefulness for prescreening additives and foaming agents for packaging applications.We modified a laboratory drawdown coating machine to allow coating of wet handsheets with foamed additives. Initial sheet solids were adjusted to a target of 8%•25% by vacuum. Foam layer thickness was set mechanically. After application, the foamed additives were drawn into the sheet with vacuum. The additive dosage was adjusted by altering its concentration within the foaming formulation. We evaluated more than 100 foaming agents and 10 strength additives, comparing wet-end and foam-assisted addition with no addition on recycled linerboard and virgin linerboard furnish. Foam-assisted addition typically displayed a much steeper dose-response curve and much higher maximum strength levels than wet-end addition. Our results suggest potential target applications for this technology, such as lightweighting, and improved strength performance in mills with relatively closed water systems, where strength aids added into the wet end are adversely influenced by accumulation of inorganic ions and organic species.
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The effect of contact time between CPAM and colloidal silica on the flocculation behavior in the approach flow, TAPPI Journal January 2021
ABSTRACT: Multicomponent wet-end systems have become increasingly common in papermaking, with the objective of improving the retention-formation-dewatering relationship. It is quite common to use at least a cationic polymer, often in combination with an anionic microparticle. In some cases, a fixative is also used. However, there is still debate on the optimal implementation of these systems. In particular, optimizing the contact time of the cationic polymer prior to addition of the anionic microparticle is still poorly understood. In this work, we investigate the effect of the contact time of a cationic polyacrylamide (CPAM) prior to addition of colloidal silica on the flocculation response in a flowing fiber suspension. The effect of using a fixative is also investigated. Focused beam reflectance measurements (FBRM) are combined with zeta-potential measurements for optimizing the addition levels of a two- and three-component system, as well as for elucidating the effect of contact time on CPAM performance. Trials are then performed on a pilot scale flow loop, where the time between addition of these two components is varied and the resulting flocculation response is characterized using high-speed filming and image analysis techniques. It is shown that the efficacy of CPAM can be improved through use of a fixative and that a longer CPAM contact time may be beneficial in terms of immediate flocculation; however, hydrodynamic shear tends to dominate the flocculation response regardless of contact time due to floc rupture.
Journal articles
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Over the Wire, Paper360º January/February 2021
Over the Wire, Paper360º January/February 2021