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Development of converging-diverging multi-jet nozzles for molten smelt shattering in kraft recovery boilers, TAPPI Journal March 2021
ABSTRACT: The effective shattering of molten smelt is highly desired in recovery boiler systems. Ideally, shatter jet nozzle designs should: i) generate high shattering energy; ii) create a wide coverage; and iii) minimize steam consumption. This study proposes a novel converging-diverging multi-jet nozzle design to achieve these goals. A laboratory setup was established, and the nozzle performance was evaluated by generating jet pressure profiles from the measurement of a pitot tube array. The results show that the shatter jet strength is greater with a large throat diameter, high inlet pressure, and a short distance between the nozzle exit and impingement position. Increasing the number of orifices generates a wider jet coverage, and the distance between the orifices should be limited to avoid the formation of a low-pressure region between the orifices. The study also demonstrates that an optimized converging-diverging multi-jet nozzle significantly outperformed a conventional shatter jet nozzle by achieving higher energy and wider coverage while consuming less steam.
Journal articles
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Evaluation of rice straw for purification of lovastatin, TAPPI Journal November 2021
ABSTRACT: Cholesterol synthesis in the human body can be catalyzed by the coenzyme HMG-CoA reductase, and lovastatin, a key enzyme inhibitor, can reduce hypercholesterolemia. Lovastatin can be obtained as a secondary metabolite of Aspergillus terreus ATCC 20542. In this study, rice straw of lignocellulose was used in aeration and agitation bath fermentation in a 1-L flask, and a maximal crude extraction rate of 473 mg/L lovastatin was obtained. The crude extract was treated with silica gel (230•400 mesh) column chromatography. Ethyl acetate/ethanol (95%) was used as the mobile phase, and isolation was performed through elution with various ethyl acetate/ethanol ratios. The highest production rate of 153 mg/L was achieved with ethyl acetate/ethanol in a ratio of 8:2. The lovastatin gained from the crude extract was added to 12 fractions treated with 0.001 N alkali, and acetone was then added. After 24 h of recrystallization at 4°C, the extract underwent high-performance liquid chromatography. The purity had increased from 25% to 84.6%, and the recovery rate was 65.2%.
Journal articles
Magazine articles
Effects of phosphogypsum whiskers modification with calcium stearate and their impacts on properties of bleached softwood paper sheets, TAPPI Journal September 2021
ABSTRACT: By combining the structural properties and characteristics of phosphogypsum whiskers, a preliminary study on the modification of phosphogypsum whiskers and their application in papermaking was carried out. The effects of reaction temperature, reaction time, and reaction concentration on the solubility and retention of modified phosphogypsum whiskers and the effects of phosphogypsum whiskers on the physical properties of paper under different modified conditions were explored. The research results show that, after the phosphogypsum whiskers are modified with calcium stearate, a coating layer will be formed on the surface of the whiskers, which effectively reduces the solubility of the phosphogypsum whiskers. The best modification conditions are: the amount of calcium stearate relative to the absolute dry mass of the phosphogypsum whisker is 2.00%; the modification time is 30 min, and the modification temperature is 60°C. The use of modified phosphogypsum whiskers for paper filling will slightly reduce the whiteness, folding resistance, burst resistance, and tensile strength of the paper, but the tearing degree and retention of the filler will be increased to some extent.
Journal articles
A laboratory-scale automated vacuum-assisted device for coating of cellulose nanofibrils onto paper, TAPPI Journal November 2025
ABSTRACT: An automated vacuum-assisted coating system was developed to deposit cellulose nanofibril (CNF) layers onto paper substrates, simulating potential industrial geometries while allowing precise control of web speed (10•20 m/min), vacuum time (up to 30 s), and applicator gap (0.5•0.9 mm). Vacuum assistance makes it possible to obtain coat weights over 5 g/m2 in a single pass and increases solids after coating from less than 10% to over 28%• 30%, reducing drying demand by more than 60%. Coat weights were tuned from 6 to over 11 g/m² by varying suspension solids (0.4•0.6 wt%), line speed, and filtration length (20•40 mm), with strong agreement between experimental data and model predictions. Barrier testing showed Kit test values for double folded samples of 9•12 and Gurley air resistances above 4 × 104 s once coat weights exceeded 7 g/m². Comparable performance was achieved with lower fines content CNF (60%) by increasing coat weight, providing technical flexibility and cost advantages for industrial scale-up.
Journal articles
Influence of base sheet properties on barrier coating performance, TAPPI Journal November 2025
ABSTRACT: Paper packaging offers a sustainable alternative to standard plastic-based materials, particularly for food and beverage applications. With reduced fiber treatment options like fluorochemicals, uncoated base stock often provides little-to-no effective barrier against liquid water, oil/grease, or moisture transmission. Despite the lack of natural barrier performance, base sheet properties can significantly influence the efficiency of applied waterbased barrier coatings. In this study, various base stock properties, such as caliper, porosity, roughness, and ash content, are reported to influence the barrier performance of styrene-acrylic and a copolymer of styrene-butadiene/styrene-acrylate based barrier coatings. These findings will help paper and board producers design better, more cost-effective, purposebuilt substrates for barrier applications in the packaging industry.
Journal articles
The industry is entering a pivotal moment in which many of us find ourselves engaged in deep soul searching. Since the days of Francis Bacon when the illustrious triumvirate of gunpowder, the compass, and paper were the drivers of civilizations, our commu
The industry is entering a pivotal moment in which many of us find ourselves engaged in deep soul searching. Since the days of Francis Bacon when the illustrious triumvirate of gunpowder, the compass, and paper were the drivers of civilizations, our community has enjoyed a noble place at the table. Indeed, especially over the last 100 years, pulp and paper has quietly powered communication, commerce, and, more than ever today, packaging, thus representing a steady backbone for the continued stability of many global industries.
Journal articles
Magazine articles
Review of coating cracking and barrier integrity on paperboard substrates, TAPPI Journal November 2022
ABSTRACT: Barrier packaging formats are major growth areas for the pulp and paper industry. It is technically challenging to maintain barrier properties during converting and end-use applications. Improved manufacturing capabilities and coating formulation knowledge will help maintain barrier integrity and enable growth of barrier products in challenging applications. These improvements will accelerate product development and commercialization, and allow faster response to product performance issues such as cracking. The literature on coating cracking provides knowledge mostly on the effects of coating formulations and to a lesser extent on substrate effects. Despite a large number of publications dedicated to coating failures, the approach to improve coating cracking remains empirical, and the transferability between studies and to real life applications has not been well established. Model development that successfully predicts commercial performance is in its infancy. However, some of these simplified models do a fairly good job predicting experimental data. The current work reviews the state of understanding as regards coating and barrier cracking and highlights the need for more research on cracking and barrier integrity.
Journal articles
Magazine articles
Effectiveness of masks in the suppression of COVID-19 cases during the ongoing pandemic in India, TAPPI Journal October 2022
ABSTRACT: Perhaps the worst predicament faced by humanity in the twenty-first century is the COVID-19 pandemic, which is caused by the SARS-CoV-2 virus. Most parts of the world, including India, went into lockdowns for some period because of the massive increase in cases throughout 2020. Face masks became an important counter-measure for protecting the populace, health professionals, and medics, particularly during the period prior to the mass availability of vaccines. This study intends to evaluate the effectiveness of face masks in limiting the spread of the virus. The data for the number of COVID-19 cases was analyzed from January 1, 2022 to May 31, 2022, using Python programming. This timeframe involved face mask mandates and no mask requirement, and hence was considered to be ideal for analyzing the usefulness of face masks. A decline in cases during the mandate was observed, while the opposite occurred without the mandate. The outcome of the research showed that face masks are effective additional measures against the spread of SARS-CoV-2. This study elevates the value of personal protective equipment (PPE), such as face masks, made with nonwovens and other fabrics, as lifesavers in the case of airborne diseases such as COVID-19 and other pulmonary disorders.
Journal articles
Magazine articles
Utilization of palm fiber as papermaking materials: Microscopic structure and chemical pulping, TAPPI Journal October 2022
ABSTRACT: The microscopic structure and pulping properties of palm fiber were explored. Soda cooking and sulfate cooking were conducted and compared in terms of physical strength of the obtained pulps. Sulfate pulp showed better performance than soda pulp, as indicated by the 23% higher tensile index, 49% higher tear index, and 36% higher burst index. To further elevate physical strength, long fibered pulp (LFP), namely commercial softwood sulfate pulp, was mixed with sulfate pulp of palm fiber at levels from 20% to 50%. At the blend level of 50%, tensile index of 52.13 Nœm/g, tear index of 15.63 mNœm2/g, and burst index of 3.42 kPaœm2/g were attained. The lignin in spent liquor from pulping was isolated and characterized. Soda lignin of palm fiber was mainly composed of guaiacyl and syringyl units, and showed weight-average molecular weight of 3616 g/mol.
Journal articles
Magazine articles
Research on improving the basis weight measurement accuracy of tissue paper based on PSO-BP neural network, TAPPI Journal October 2022
ABSTRACT: The near-infrared (NIR) sensor can be used for measuring the basis weight and moisture of tissue paper, but the measurement accuracy is not ideal for this paper grade. The weight range of the tissue is 10~30 g/m2, indicating that it is a low gram weight paper. The temperature and humidity of the production environment significantly impact an NIR sensor. This paper focuses on improving the measurement accuracy of tissue paper basis weight. In order to reduce the influences of temperature and humidity, a mathematical model based on a particle swarm optimization back propagation (PSO-BP) neural network is proposed. In comparison with multiple linear regression measurement models, the basis weight measurement error with the PSO-BP model is within ± 0.5 g/m2. This model can effectively improve the measurement accuracy and has a good effect on overcoming the basis weight nonlinear effect caused by the changes in ambient temperature and humidity.