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Journal articles
Dispersion of pulp slurries using carboxymethylcellulose, TAPPI JOURNAL, October 2000, Vol. 83(10)
Dispersion of pulp slurries using carboxymethylcellulose, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
Infrared analysis for process control in the pulp and paper industry, TAPPI JOURNAL, October 2000, Vol. 83(10)
Infrared analysis for process control in the pulp and paper industry, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
Pulp bleaching with manganese peroxidase and xylanase: a synergistic effect, TAPPI JOURNAL, October 2000, Vol. 83(10)
Pulp bleaching with manganese peroxidase and xylanase: a synergistic effect, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
An image analysis method to quantify fibre separation in wood subjected to fatigue loading, TAPPI JOURNAL, December 2000, Vol. 83(12)
An image analysis method to quantify fibre separation in wood subjected to fatigue loading, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Application of polyallylamine as a dry strength agent for paper, TAPPI JOURNAL, December 2000, Vol. 83(12)
Application of polyallylamine as a dry strength agent for paper, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Pulping of aspen wood in acetic acid media: effect of operating conditions on yield and pulp properties, TAPPI JOURNAL, December 2000, Vol. 83(12)
Pulping of aspen wood in acetic acid media: effect of operating conditions on yield and pulp properties, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Magazine articles
Numerical analysis of the impact of rotor and screen hole plate design on the performance of a vertical pulper, TAPPI Journal April 2025
ABSTRACT: The dissolving of mechanical pulp is one of the most important process steps in stock preparation, since pulping occurs at the very beginning of the papermaking process. Efficient mixing of the pulp in a short amount of time is essential to achieve high furnish volume flow rates. The design of the rotor, as well as the pulper vat and inserts, significantly affects the overall performance of the pulper, such as mixing efficiency and power demand. Using advanced numerical methods such as computational fluid dynamics (CFD) can accelerate the development process. The CFD simulations allow for detailed analysis of flow phenomena, making it possible to study a real-size machine numerically. This approach is particularly advantageous because it can reduce the need for timeconsuming and costly experiments associated with scaling up test rigs. In this study, we compared two different rotor designs utilized in a vertical pulper and evaluated the numerical results with experimental data. Rotor A is designed for low turbulence and low power demand, while rotor B is designed for high turbulence with high power demand. The CFD results showed good agreement with the experimental measurements. We investigated how the rotor design influences the free fluid surface and the mixing efficiency. Our study also highlights the differences in results depending on whether water or furnish is simulated, which exhibit Newtonian or, respectively, non-Newtonian fluid behavior. Additionally, a detailed numerical investigation of various screen hole plate designs revealed that the newly developed hole design significantly reduces pressure loss compared to a standard drilled hole. This outcome was consistent for both types of fluids investigated: water and furnish.
Journal articles
Materials performance considerations in hydrothermal liquefaction conversion of biomass, TAPPI Journal June 2025
ABSTRACT: Hydrothermal liquefaction (HTL) is a promising thermochemical route developed to convert woody biomass and biowaste to biochemicals and bio-oils. However, the operating conditions are rather harsh to biorefinery structural metallic components. These conditions include alkaline catalysts such as potassium carbonate (K2CO3); hot, pressurized (sub-critical) water reaction; and medium and aggressive anions chlorine (Cl•) and hydrogen sulfide (H•) released from biomass feedstocks. Thus, selection of suitable structural alloys for biorefinery components involves striking a balance between mechanical properties, corrosion resistance, and cost. Alloys currently being considered for this application include ferritic-martensitic steels and austenitic stainless steels. From a corrosion perspective in hot pressurized water, the former typically exhibits higher stress corrosion cracking resistance, whereas the latter exhibits higher corrosion resistance. This study reviews cost-effective corrosion control strategies aimed at increasing the chromium (Cr) content for protective surface oxide formation, as screened by testing in simulated HTL alkaline water, to support materials selection and design. Corrosion control strategies include surface modification (increasing surface Cr content), alloying (increasing bulk Cr content), and stainless-steel type (ferritic vs. austenitic). Of the alloys considered (including those subjected to surface modification), ferritic stainless steels exhibit a promising balance between corrosion and stress corrosion cracking resistance, adding another family of candidate alloys for structural biorefinery component materials selection and design.
Journal articles
Conversion of paper-grade pulp from rice straw into dissolving pulp, TAPPI Journal June 2025
ABSTRACT: About 1,165 million metric tons of rice straw is generated every year worldwide, which can be a good source for the circular bioeconomy. In this research paper, the paper-grade pulp from rice straw was converted to dissolving-grade pulp by fractionation in a biorefinery initiative. Rice straw was cooked at an optimum condition of 8% potassium hydroxide (KOH) charge for 120 min at 150°C and produced a pulp yield of 47.2% with a kappa number of 18.5. Subsequently, D0(EP)D1 bleaching was carried out for the produced pulp, and the brightness of the pulp reached to 82.4%. From the black liquor, 16.5% of the lignin and 11.9% of the hemicellulose were isolated for producing biobased products and chemicals, and then the spent liquor was used for soil amendment. The bleached pulp was fractionated in a Bauer McNett fiber classifier. The pulp fibers retained on 16-, 30-, and 50-mesh screens were used as a longer fiber fraction pulp, and pulp fibers retained on 100- and 200-mesh screens were used as a shorter fiber pulp. The longer and shorter fiber fraction pulps were analyzed for cellulose, R10, pentosan, and viscosity. The long fiber fraction pulps were characterized by higher cellulose (88.2% vs. 83.1%) and lower pentosan (11.3% vs. 13.0%) content than the shorter fiber fraction pulps. The longer fiber fraction was further treated with cold KOH to remove residual hemicellulose. The KOH extraction reduced pentosan content in pulp to 6.3% and increased á-cellulose content to 91.3%. The short fiber fraction was converted to monomeric sugars using cellulase enzymes with varying reaction time, temperature, and consistency. The efficiency of cellulase activity was assessed through glucose yield and residual dry weight. A temperature of 45°C, 5.0 pH, 5% consistency, and 6 filter paper units/gram (FPU/g) o.d. pulp resulted in maximum sugar conversion of 85.7%.
Journal articles
The effect of Stachys floridana Shuttlew.ex Benth extract as an additive on the chemical properties of chitosan biodegradable film, TAPPI Journal June 2025
ABSTRACT: The purpose of this study is to explore chitosan with Stachys floridana Shuttlew. ex Benth (SFSB) extract as an additive to prepare an active film. The effects of the SFSB extract on the physical, antioxidant, and bacteriostatic properties of chitosan biodegradable films were studied. The results showed that the addition of SFSB extract significantly improved the antioxidant and antibacterial properties of the film, and its biodegradation rate increased rapidly. Compared to the control film, the water solubility was lower at 19.40%, the expansion degree was higher at 288.90%, the water vapor permeability (WVP) was 0.364 g·mm/(m²·d·kPa), the surface hydrophobicity increased, and the mechanical strength was also improved. The contact angle increased to 89.3°. In addition, as the amount of SFSB increased, the thermal stability of chitosan-Stachys floridana Shuttlew. ex Benth (CS-SFSB) films also increased significantly, and their ultraviolet (UV) blocking ability was gradually enhanced. The results indicate that CS-SFSB has potential as a food packaging material.