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The sticky behavior of pulp and paper mill biosludge during drying, TAPPI Journal June 2019
ABSTRACT: Pulp and paper mill biosludge becomes sticky after being dried to a certain solids content. As bio-sludge becomes sticky, it agglomerates and adheres to the heat transfer surfaces of the dryer. This undesirable property can lower the dryer efficiency and cause the drying equipment to fail.A systematic study was conducted to examine the sticky behavior of biosludge. The stickiness was evaluated by measuring the adhesive force between a sludge cake and a stainless steel substrate, and the cohesive force between a sludge cake and a sludge substrate. The results show that: i) both adhesive and cohesive forces increase markedly as the solids content increases, reaching a maximum value at about 13% solids, and then decrease steadily at a high-er solids content; ii) cohesive force is stronger than adhesive force, implying that biosludge tends to agglomerate rather than adhere to smooth equipment surfaces; and iii) mixing wood fines or fly ash from a biomass boiler reduc-es the stickiness of the mixture. These findings may help mills improve the thermal efficiency of biosludge dryers and to turn biosludge into a more attractive fuel for burning in biomass boilers.
Journal articles
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Fabrication of cross-linked starch-based nanofibrous mat with optimized diameter, TAPPI JOURNAL June 2019
ABSTRACT: The design and synthesis of natural and synthetic polymer blends have received recent and wide attention. These new biomaterials exhibit progress in properties required in the field of medicine and healthcare. Herein, the aim of present study is to fabricate starch (ST)/polyacrylic acid (PAA) electrospun nanofibrous mat with a smooth and uniform morphology, lowest fiber diameter (below 100 nm) and the highest possible starch content. Starch itself is poor in process-ability, and its electrospinning could be quite a challenging process. To address this, we carried out the response surface methodology (RSM) technique for modelling the electrospinning process. In order to have ST/PAA nanofibers with the finest possible diameter, optimized processing parameters (applied volt-age, nozzle-collector distance and feed rate) obtained from RSM technique were applied. ST/PAA electrospun nano-fibers with an average diameter of 74±13 nm were successfully achieved via the electrospinning method for the first time. The structure, preparation and properties of the nanofibrous structure were discussed. Results indicated that drug loaded ST/PAA blend nanofibrous structure has a great potential to be used in controlled drug release systems.
Journal articles
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Large data set analysis to determine refiner plate total cost of ownership, TAPPI Journal June 2019
ABSTRACT: Efficient process data storage and its subsequent analysis are vital to the profitable operation of a paper mill. An evaluation of refiner plate performance was conducted for an integrated paper mill. Trials with two new plate patterns were compared with the incumbent pattern; the goal was to increase refiner plate life. Plate life increased with both new design patterns, and the mill selected one of the two new choices. However, addi-tional impacts to paper machine performance and mill maintenance costs were not considered in the selection deci-sion. A large data set analysis tool was used to identify unrealized savings of 1.5% with reduced fiber usage (basis weight) on the paper machine’s most prevalent grade. The large data analysis indicated that this unrealized benefit with the alternate plate design was not attainable with the chosen plate design.
Journal articles
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Editorial: TAPPI Journal 2018 Best Research Paper delves deeper into press section rewet to address drying efficiency, TAPPI Journal March 2019
ABSTRACT: TAPPI and the TAPPI Journal (TJ) Editorial Board would like to congratulate the authors of the 2018 TAPPI Journal Best Research Paper Award: J. David “Dave” McDonald and Richard J. “Dick” Kerekes. Their paper, “Rewet in wet pressing of pa-per,” appeared on p. 479 of the September 2018 issue. This research was recognized by the Editorial Board for its in-novation, creativity, scientific merit, and clear expression of ideas.
Journal articles
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A study of the softness of household tissues using a tissue softness analyzer and hand-felt panels, TAPPI Journal March 2019
ABSTRACT: This study applied the reciprocal matrix approach to deduce the correlation between hand-felt (HF) and tissue softness analyzer (TSA) instrumental measurements of tissue softness. The research was conducted in three phases, which are discussed separately. In the phase one study, results indicated that systematic collection of samples and preparation of test specimens were the foundation of successful tests. TSA-HF and tensile strength exhibited a strong negative correlation. In the future, same-unit physical properties can provide a basis for discuss-ing the commonality and complementary natures of hand-felt and TSA softness measurements. In phase two, through the reciprocal matrix approach, subjective softness assessments performed by humans were reliably quan-tified. The quantified values were further applied to a statistical analysis using the t-test to distinguish and train pro-fessional panelists. In phase three of HF panel test results, all independent panels were compared to one another under a uniform scale established by four standard samples. The calibrated HF panel values were incorporated with TSA-HF results to establish technical curves between the softness and tensile strength, which were helpful for onsite workers to carry out process controls.
Journal articles
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Creating adaptive predictions for packaging-critical quality parameters using advanced analytics and machine learning, TAPPI Journal November 2019
ABSTRACT: Packaging manufacturers are challenged to achieve consistent strength targets and maximize pro-duction while reducing costs through smarter fiber utilization, chemical optimization, energy reduction, and more. With innovative instrumentation readily accessible, mills are collecting vast amounts of data that provide them with ever increasing visibility into their processes. Turning this visibility into actionable insight is key to successfully exceeding customer expectations and reducing costs. Predictive analytics supported by machine learning can provide real-time quality measures that remain robust and accurate in the face of changing machine conditions. These adaptive quality “soft sensors” allow for more informed, on-the-fly process changes; fast change detection; and process control optimization without requiring periodic model tuning.The use of predictive modeling in the paper industry has increased in recent years; however, little attention has been given to packaging finished quality. The use of machine learning to maintain prediction relevancy under ever-changing machine conditions is novel. In this paper, we demonstrate the process of establishing real-time, adaptive quality predictions in an industry focused on reel-to-reel quality control, and we discuss the value created through the availability and use of real-time critical quality.
Journal articles
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Editorial: A preview of PEERS 2019, TAPPI Journal September 2019
ABSTRACT: Coming soon is PEERS • TAPPI’s annual Pulping, Engineering, Environmental, Recycling and Sustainability gathering for industry professionals. Held this October 27-30 in St. Louis, MO, the conference is co-located with the International Bioenergy & Bioproducts Conference (IBBC) and the 12th Research Forum on Recycling. Universities and research organizations from around the world are represented in the conference content, and below is a sampling of just a few of the many presentations that might interest TAPPI Journal readers.
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Critical parameters for tall oil separation I: The importance of ration of fatty acids to rosin acids, TAPPI Journal September 2019
ABSTRACT: Tall oil is a valuable byproduct in chemical pulping of wood, and its fractions have a large spectrum of applications as chemical precursors, detergents, and fuel. High recovery of tall oil is important for the economic and environmental profile of chemical pulp mills. The purpose of this study was to investigate critical parameters of tall oil separation from black liquor. To investigate this in a controlled way, we developed a model test system using a “synthetic” black liquor (active cooking chemicals OH- and HS- ions), a complete process for soap skimming, and determination of recovered tall oil based on solvent extraction and colorimetric analysis, with good reproducibility. We used the developed system to study the effect of the ratio of fatty acids to rosin acids on tall oil separation. When high amounts of rosin acids were present, tall oil recovery was low, while high content of fatty acids above 60% significantly promoted tall oil separation. Therefore, manipulating the content of fatty acids in black liquor before the soap skimming step can significantly affect the tall oil solubility, and hence its separation. The findings open up chemical ways to improve the tall oil yield.
Journal articles
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A new technique for the measurement of show-through mottle of fine paper, TAPPI Journal September 2019
ABSTRACT: Mottling within print-through and show-through is caused by the variability of the local optical properties of the sheet. This mottling is visually disturbing and a mark of poor paper quality. The ability to predict print-through mottle of printed paper by measuring show-through mottle on the unprinted sheet would be a valuable asset for paper machine control.We examined the relationship between print-through mottle and show-through mottle. We worked with nine samples of 60 lb. uncoated fine paper (90 g/m2), from various North American paper companies, that were printed on an offset press, 400K (400% Black), on both sides. A show-through mottle instrumental determination technique was developed using an existing Fast Fourier Transform-based algorithm. The nine samples examined were ranked similarly by the visual evaluation of print-through mottle and by the instrumental determination of show-through mottle. We thus established that show-through on the unprinted sheet can be used as a reliable predictor of print-through, therefore saving time and money for papermakers. We also found a significant two-sidedness in show-through for some of the samples.
Journal articles
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Editorial: Snapshot from the pandemic: TAPPI Journal Editorial Board shares their experiences, TAPPI Journal April 2020
ABSTRACT: In this most serious time of the global COVID-19 pandemic, I and TAPPI staff have been fortunate to work remotely and practice social distancing. The same goes for our Editorial Board. Still, the business of papermaking has continued, and those on our Board who support the industry through their work and research have had to make adjustments. Here, members of the Editorial Board share their experiences of working during the pandemic. As we all anticipate returning to a new normal that once again allows face-to-face interaction, we hope our TAPPI Journal readers stay safe and healthy as we all personally and professionally navigate this challenging time.