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Journal articles
Magazine articles
A hundred years of corrosion in the pulp and paper industry, TAPPI JOURNAL May 2018
A hundred years of corrosion in the pulp and paper industry, TAPPI JOURNAL May 2018
Journal articles
Magazine articles
Kraft pulp bleaching with a P-stage catalyzed by both bicarbonate and TAED, TAPPI Journal July 2019
ABSTRACT: Peroxide bleaching of softwood and hardwood (eucalypt) kraft pulps was performed in solutions of sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3), and sodium hydroxide (NaOH). The conventional P stage (hydrogen peroxide + sodium hydroxide; H2O2 + NaOH) was the most effective brightening system without an additional activator. However, peroxide activation by bicarbonate anion (HCO3•) was obvious in all cases where NaHCO3 or Na2CO3 was used. When N,N,N’,N’-tetraacetylethylenediamine (TAED) was added to the bleaching sys-tem, Na2CO3 as the alkali source afforded equal or slightly higher bleached brightness compared to NaOH usage for both the softwood and hardwood pulps. This outcome is attributed to simultaneous peroxide activation by HCO3• and TAED. When applied to the eucalypt pulp, the H2O2/Na2CO3/TAED bleaching system also decreased the bright-ness loss due to thermal reversion.
Journal articles
Magazine articles
Fundamental molecular characterization and comparison of the O, D0, and E stage effluents from hardwood pulp bleaching, TAPPI Journal 2019
ABSTRACT: The present study characterized effluents from the O, D0, and E stages using nuclear magnetic reso-nance (NMR) and gel permeation chromatography (GPC) techniques to better understand the chemical nature of the dissolved organics formed from the bleaching of a high-yield hardwood kraft pulp. Understanding the structures and molecular weight distribution of these organics is the first step in developing methods to mitigate these contam-inates in the discharged effluents. The results indicated that the molecular weight distribution (MWD) of the dis-solved organics from oxygen delignification effluent is broader than those from D0 and E stage effluents. In addition, the O stage filtrate contained considerable amounts of lignin and xylan fragments, which showed its efficiency in removing such materials. The effluent from the D0 stage contained a lower amount of high molecular weight frag-ments and a higher amount of low molecular weight fragments versus the O-stage filtrate. Aromatic structures were nearly absent in the D0 stage filtrate, but the degraded organic material, presumably from oxidized lignin, contained olefinic (C=C) and carbonyl (C=O) functional groups. Furthermore, higher molecular weight fragments were detected in the E-stage effluent, presumably due to the extensive solubilization and removal of the oxidized lignin generated from the D0 pulp.
Journal articles
Magazine articles
Editorial: 2018 TAPPI Journal features diverse content, TAPPI Journal November 2018
Editorial: 2018 TAPPI Journal features diverse content, TAPPI Journal November 2018
Journal articles
Magazine articles
Understanding the risks and rewards of using 50% vs. 10% strength peroxide in pulp bleach plants, TAPPI Journal November 2018
Authors: Alan W. Rudie and Peter W. Hart | ABSTRACT: The use of 50% concentration and 10% concentration hydrogen peroxide were evaluated for chemical and mechanical pulp bleach plants at storage and at point of use. Several dangerous occurrences have been documented when the supply of 50% peroxide going into the pulping process was not stopped during a process failure. Startup conditions and leaking block valves during maintenance outages have also contributed to explosions. Although hazardous events have occurred, 50% peroxide can be stored safely with proper precautions and engineering controls. For point of use in a chemical bleach plant, it is recommended to dilute the peroxide to 10% prior to application, because risk does not outweigh the benefit. For point of use in a mechanical bleach plant, it is recommended to use 50% peroxide going into a bleach liquor mixing system that includes the other chemicals used to maintain the brightening reaction rate. When 50% peroxide is used, it is critical that proper engineering controls are used to mitigate any risks.
Journal articles
Magazine articles
Using multistage models to evaluate how pulp washing after the first extraction stage impacts elemental chlorine-free bleach demand, TAPPI Journal November 2018
Using multistage models to evaluate how pulp washing after the first extraction stage impacts elemental chlorine-free bleach demand, TAPPI Journal November 2018
Journal articles
Magazine articles
Laboratory method for determining the source of brightness loss at a southern United States bleached paperboard mill, TAPPI Journal October 2018
Laboratory method for determining the source of brightness loss at a southern United States bleached paperboard mill, TAPPI Journal October 2018
Journal articles
Magazine articles
Alternative “green” lime kiln fuels: Part II—Woody biomass, bio-oils, gasification, and hydrogen, TAPPI Journal May 2020
ABSTRACT: This paper is the second of a two-part series on “green” lime kiln fuels. The first part of this work reviews the use of pulp mill and recovery byproducts as either full or partial replacement of oil or natural gas in the kiln. The second part reviews the use of various forms of woody biomass, bio-oils, gasification and hydrogen as potential carbon neutral or carbon-free lime kiln fuels. Several of these options require specialized burners to supply the fuel to the kiln and high-quality metallurgy to withstand the acidic conditions of the fuel.
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.