Search
Use the search bar or filters below to find any TAPPI product or publication.
Filters
Content Type
Publications
Level of Knowledge
Committees
Collections
Journal articles
Magazine articles
Effect of high sulfate content on viscosity of recovery boiler molten smelt, TAPPI Journal March 2024
ABSTRACT: A systematic study was conducted to examine the effect of high sulfate content on the freezing temperature of molten smelt and how this may contribute to the formation of viscous jellyroll smelt in recovery boilers. The results show that even for recovery boilers with a smelt reduction as low as 70%, the sulfate content in smelt has no or little effect on smelt freezing temperature, and hence, on molten smelt fluidity. The perceived adverse effect of high sulfate content on smelt fluidity and on jellyroll smelt formation comes from the high sulfate content in deposits that have fallen from the upper furnace. Fallen deposits may or may not form jellyroll smelt, depending on whether or not they can melt and be well-mixed with molten smelt by the time they reach the smelt spouts. It is not the high sulfate content in smelt resulting from the low smelt reduction efficiency that makes molten smelt viscous and forms jellyroll smelt, but rather, it is the incomplete melting of fallen deposits that results in one of the proposed mechanisms for jellyroll smelt formation.
Journal articles
Magazine articles
In-process detection of fiber cutting in low consistency ref
In-process detection of fiber cutting in low consistency refining based on measurement of forces on refiner bars, TAPPI JOURNAL April 2017
Journal articles
Magazine articles
Photo-catalytic degradation of gaseous pollutants in paper mills of southern China, TAPPI JOURNAL March 2018
Photo-catalytic degradation of gaseous pollutants in paper mills of southern China, TAPPI JOURNAL March 2018
Journal articles
Magazine articles
Use of vent stack temperature as a feedforward variable for dissolver total titratable alkali (TTA) control, TAPPI JOURNAL May 2018
Use of vent stack temperature as a feedforward variable for dissolver total titratable alkali (TTA) control, TAPPI JOURNAL May 2018
Journal articles
Magazine articles
Operational limits of blade coating associated with high aspect ratio pigments: Part I—bench top blade coater, TAPPI Journal February 2019
Operational limits of blade coating associated with high aspect ratio pigments: Part I—bench top blade coater, TAPPI Journal February 2019
Journal articles
Magazine articles
Operational limits of blade coating assocciated with high aspect ratio pigments: PartII—cylindrical laboratory coater, TAPPI Journal February 2019
Operational limits of blade coating assocciated with high aspect ratio pigments: PartII—cylindrical laboratory coater, TAPPI Journal February 2019
Journal articles
Magazine articles
A novel predictive method for filler coflocculation with cellulose microfibrils, TAPPI Journal November 2019
ABSTRACT: Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and benonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.
Journal articles
Magazine articles
Lignin-based resins for kraft paper applications, TAPPI Journal November 2019
ABSTRACT: We investigated miscanthus (MS) and willow (W) lignin-furfural based resins as potential reinforce-ment agents on softwood and hardwood kraft paper. These resins might be sustainable alternatives to the commercial phenolformaldehyde (PF) resins. Phenol is a petrochemical product and formaldehyde has been classified as a carcinogen by the U.S. Environmental Protection Agency. The lignin used in this study was derived from hot water extraction (160ºC, 2 h) of MS and W biomass, and may be considered sulfur-free. These biorefinery lignins were characterized for their chemical composition and inherent properties via wet chemistry and instrumental techniques. The resin blends (MS-resin and W-resin) were characterized for their molecular weight, thermal behavior, and mechanical properties. Mechanical properties were measured by the resin’s ability to reinforce softwood and hard-wood kraft papers. The effect of adding hexamethylenetetramine (HMTA), a curing agent, to the resin was also examined. Mixtures of PF and lignin-based resins were investigated to further explore ways to reduce use of non-renewables, phenol, and carcinogenic formaldehyde. The results show that lignin-based resins have the potential to replace PF resins in kraft paper applications. For softwood paper, the highest strength was achieved using W-resin, without HMTA (2.5 times greater than PF with HMTA). For hardwood paper, MS-resin with HMTA gave the highest strength (2.3 times higher than PF with HMTA). The lignin-based resins, without HMTA, also yielded mechanical properties comparable to PF with HMTA.
Journal articles
Magazine articles
Flow characteristics of drag-reducing natural bamboo fiber suspensions with minimal environmental load, TAPPI Journal September 2019
ABSTRACT: The reduction of pipe friction loss by adding drag-reducing agents has attracted attention as an aid to energy conservation. Drag-reducing agents induce drag reduction (DR) effects and should have a minimal environmental load, with natural resource-saving potential. This study demonstrates bamboo fiber as a drag-reducing agent that saves natural resources and has a low environmental load. Using pressure drop measurements, we report DR with suspensions of bamboo fibers with the average diameter of 13.3 µm and aspect ratio of 98.7. The maximum DR obtained in this experiment is 43% at the concentration of 4000 ppm and pipe diameter of 30 mm; DR is affected by the Reynolds number, suspension concentration, and pipe diameter. In addition, the bamboo fibers can be easily removed from the suspensions by filtration. We found that low-environmental-load bamboo fiber has DR effects like those of other fibers; its effects are greater than those of conventional synthetic fibers and wood pulp. Furthermore, it is resistant to mechanical degradation, recoverable, and recyclable. Therefore, DR effects can be selectively obtained by adding the fibers only when DR is needed; the fibers can then be collected when DR is no longer necessary. This method might greatly expand the application range of DR agents. The results demonstrate the usefulness of bamboo fibers as DR additives.
Journal articles
Magazine articles
Multifunctional barrier coating systems created by multilayer curtain coating, TAPPI Journal November 2023
ABSTRACT: Functional coatings are applied to paper and paperboard substrates to provide resistance, or a barrier, against media such as oil and grease, water, water vapor, and oxygen, for applications such as food packaging, food service, and other non-food packaging. Today, there is increasing interest in developing recyclable and more sustainable approaches for producing these types of packages. This paper focuses on water-based barrier coatings (WBBC) for oil and grease resistance (OGR), water, moisture vapor transmission rate (MVTR), and oxygen barrier performance. The main goal is to create coated systems that can achieve more than one barrier property using multilayer curtain coating (MLCC) in a single application step. One advantage is in optimizing coating material cost with the use of functional chemistry in confined layers where performance is balanced within the coating layered structure. This allows simultaneous application of layers of different polymer types in one step to achieve the appropriate performance needs for a given barrier application. This paper provides working examples of using MLCC to create coating structures with multiple barrier properties in a single application pass. Barrier polymers studied include styrene butadiene, styrene acrylate, starch-containing emulsions, and polyvinyl alcohol. The paper also shows the effect of increasing the pigment volume concentration with platy clay or fine ground calcium carbonate on MVTR and OGR barrier properties.