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Journal articles
Estimation of the S/G Ratios of the Lignins in Three Widely
Estimation of the S/G Ratios of the Lignins in Three Widely used North American Hardwoods, TAPPI JOURNAL July 2016
Journal articles
Corrosion Mnitoring and Root Cause Identification in High So
Corrosion Mnitoring and Root Cause Identification in High Solids Concentrators, TAPPI JOURNAL July 2016
Journal articles
Evaluation of Near-Drum Thinning Data in Recovery Boiler Gen
Evaluation of Near-Drum Thinning Data in Recovery Boiler Generating Bank Tubes, TAPPI JOURNAL July 2016
Journal articles
An elliptical pore model for the mechanical properties of pa
An elliptical pore model for the mechanical properties of paper, TAPPI JOURNAL August 2015
Journal articles
Fast evaluation of spatial coating layer formation using ultraviolet scanner imaging
Fast evaluation of spatial coating layer formation using ultraviolet scanner imaging
Journal articles
Some observations towards improved predictive models for box compression strength, TAPPI JOURNAL August 2015
Some observations towards improved predictive models for box compression strength, TAPPI JOURNAL August 2015
Journal articles
Reducing aox by increasing oxidation potential in the first
ABSTRACT An increase in the standard oxidation potential of the reinforcing agent in the first caustic extraction stage will reduce the amount of AOX in the stage's effluent. A chlorinated broumstock pulp was treated alternatively in a basic caustic extraction (E) stage, an oxygen-reinforced caustic extraction (EO) stage, and an extraction stage reinforced with oxygen and peroxide (EOP). An AOX reduction of up to 30% was obtained in the effluent from the peroxide-reinforced extraction stage. In addition to the brownstock work, using two different model lignin compounds, we ran tests using oxyen, potassium permanganate, hydrogen peroxide with oxygen, and ozone with oxygen-reinforced caustic stages. In all cases, increasing the oxidation potential of the reinforcing agent decreased the amount of AOX detected in the effluent.
Journal articles
Water and grease resistance of paperboard coated with long chain cellulose fatty acid esters using electrostatic powder coating, TAPPI Journal April 2026
ABSTRACT: Fiber-based materials used for foodservice, takeaway, and other packaging applications must typically provide water and grease resistance. Simultaneously, there is growing interest towards bio-based and renewable barrier coatings. In this study we applied thermoplastic long chain fatty acid cellulose esters onto paperboard using electrostatic powder coating to create barrier properties of interest. Electrostatic powder coating provides a water-free process to tackle moisture-induced quality issues and to provide an even coating layer. Cellulose octanoate and palmitate esters were produced in pilot scale. These were ground into fine particles using liquid nitrogen and applied onto paperboard sheets using an electrostatic powder gun. The loosely packed coatings were fixed and fused onto the paperboard by hot pressing. We characterized the coated sheets for coating thickness, contact angles with water, water absorption, grease resistance (KIT), and olive oil barrier. Two commercial polyethylene powders were used as references. Our results indicated that the long chain cellulose fatty acid ester coatings were thermoplastic and hydrophobic with contact angles above 100°. Water absorption was similar to the reference coatings. While grease resistance was lower than with the references, the cellulose ester coatings slowed down diffusion of olive oil through the paperboard. Cellulose octanoate ester with a lower melt viscosity already provided smooth coatings after the initial hot pressing step, while in most cases, the second post hot pressing step further improved the barrier properties.
Journal articles
Optimization of energy efficiency and condensate production in evaporation plants for a modern softwood pulp mill, TAPPI Journal April 2026
ABSTRACT: To meet the need to further improve thermal efficiency and environmental performance of kraft pulp mills, new systems and techniques have been developed within the evaporation plant. This paper describes these novel approaches and how they were implemented in a project completed in 2018 for a new evaporator and condensate treatment system supplied by Valmet at the SCA Östrand market pulp mill in Sweden. This project was part of a stepwise upgrade of the complete mill to increase the production capacity of the mill from 430,000 to 900,000 air-dried metric tons/year (ADt/y). As part of this upgrade, the mill had the objectives to increase the energy efficiency of the pulp mill and to minimize the air emissions as much as possible, the effluent volume, and the water usage in the mill. The mill also wanted to have the disposal of the biosludge in the black liquor, and the production of tall oil from black liquor soap, liquid methanol, and turpentine. This required that the new evaporation and condensate treatment system be very closely integrated into the other process departments of the mill, including integration of the hot weak black liquor flash vapor from the digester directly into the evaporator train and the production of multiple streams of clean evaporation plant condensate at the correct temperature for the bleach plant. Heat and mass balance calculation values, which were found to do very well in predicting the effect on actual mill operation, are also presented in this paper.
Journal articles
Assessing lignin content in Nordic hardwood and softwood species using models based on near-infrared (NIR) spectral data and partial least squares regression (PLSR), TAPPI Journal September 2025
ABSTRACT: Continuous kraft cooking digesters face challenges affecting product quality, making it valuable to improve control through advanced techniques like near-infrared (NIR) spectroscopy, model predictive control, and machine learning models. The primary goal of this study was to use NIR spectra to predict the amount of lignin in hardwood and softwood samples. This study investigated the correlation of NIR derivative spectra with the amounts of lignin relative to other constituents, namely cellulose, hemicellulose, and water, in wood chip samples of varying chip sizes and shapes from six Nordic wood species. It employed partial least squares regression (PLSR) on the NIR data to construct a model that predicted the lignin fraction and the relative fraction of acid-soluble lignin. When trained on a group of five wood species, the model achieved a satisfactory predictive ability, striking a balance between a wide range of lignin content and a consistent chemical environment. The accuracy increased further when the model was restricted only to spruce and pine, reflecting the benefits of a more homogenous dataset. Additionally, the optimal number of latent variables was identified as two, indicating that three distinct chemical components — cellulose, lignin and water — can be effectively differentiated using NIR.