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Journal articles
A New Model for Maximizing the Bending Stiffness of a Symmetric Three-Ply Paper or Board, TAPPI JOURNAL October 2008
A New Model for Maximizing the Bending Stiffness of a Symmetric Three-Ply Paper or Board, TAPPI JOURNAL October 2008
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.
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
Effects of pulverized coal fly-ash addition as a wet-end filler in papermaking, TAPPI JOURNAL September 2008
Effects of pulverized coal fly-ash addition as a wet-end filler in papermaking, TAPPI JOURNAL September 2008
Journal articles
The effects of dissolved solids on the vapor-liquid equilibrium of DMS in black liquor, TAPPI JOURNAL September 2008
The effects of dissolved solids on the vapor-liquid equilibrium of DMS in black liquor, TAPPI JOURNAL September 2008
Journal articles
A gravity model analysis of China's pulp and paper products trade, TAPPI JOURNAL September 2008
A gravity model analysis of China's pulp and paper products trade, TAPPI JOURNAL September 2008
Journal articles
Economic potential of black liquor electrolysis as a treatment option for small agro-based mills, TAPPI JOURNAL November 2009
Economic potential of black liquor electrolysis as a treatment option for small agro-based mills, TAPPI JOURNAL November 2009
Journal articles
Monitoring kraft recovery boiler fouling using principal component analysis, TAPPI JOURNAL November 2009
Monitoring kraft recovery boiler fouling using principal component analysis, TAPPI JOURNAL November 2009
Journal articles
Co-refining interactions among white birch, hybrid larch and black spruce species, TAPPI JOURNAL November 2009
Co-refining interactions among white birch, hybrid larch and black spruce species, TAPPI JOURNAL November 2009
Journal articles
Hexenuronic Acid in South African Eucalyptus Hybrid Clones: Optimization of the Acid Hydrolysis (A) Stage, TAPPI JOURNAL October 2009
Hexenuronic Acid in South African Eucalyptus Hybrid Clones: Optimization of the Acid Hydrolysis (A) Stage, TAPPI JOURNAL October 2009