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Developing and Using Modeling to Understand and Improve Industrial Oxygen Delignification Processes, TAPPICon25

Water-barrier coating based on lignin oil found on the principle of an O/W Pickering emulsion stabilized by different nanocelluloses together with or without pectin, TAPPICon25

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.

Simplified modeling of a complete rotary lime kiln at a pulp mill, TAPPI Journal February 2026

ABSTRACT: Rotary lime kilns are essential and complex components in pulp mills using the kraft process. They are primarily used to produce lime (CaO), which is then employed to make white liquor, the reagent used to separate wood fibers. To understand and improve the performance of the kiln, modeling its behavior is essential. However, the kiln operates through a complex combination of thermal and chemical phenomena. That is why a simplified approach was used to tackle this challenge. A zero/one-dimensional steady-state analysis was performed based on first principles to simplify the modeling process and reduce the need for experimental data. Additional assumptions, such as steady-state operation and the absence of a refractory lining, were introduced to further simplify the model so that it can be used for daily analysis. Moreover, the auxiliary equipment of the plant, such as the intercooler and preheat cyclone, is also modeled. The final model was validated using data from the literature and a two-month analysis of experimental measure-ments from the Burgo Ardennes lime kiln in Virton, Belgium. It shows good agreement with the available data, with a 6% deviation for the adiabatic flame temperature and a 17% average error in predicting the kiln shell outside temperature. For the fuel and lime flow rate predictions, also validated over the same two-month period, the errors were -6.6% and 0.6%, respectively.

Full-scale operation of a membrane-based black liquor concentrator, TAPPI Journal January 2026

ABSTRACT: For years, black liquor concentration by reverse osmosis has been an aspiration for reducing mill energy consumption and costs. Building on a 2023 report of an 81% reduction in the energy intensity for concentrating black liquor using its membrane platform at the pilot scale, this paper reports on the fabrication, installation, startup, and operation of the world’s first full-scale membrane-based black liquor concentration system at the International Paper Grande Prairie mill in Canada. The majority of the membrane modules in this system have reliably exceeded permeability expectations by more than 50%. In addition to strong membrane performance, the system has been a significant source of learnings for material specifications and system design. Incorporating these learnings and comparing to typical multiple effect evaporators, the system demonstrates a 43% reduction in capital cost for the same capacity, a 30% reduction in the lifetime cost of removing water from black liquor, and an 86% reduction in energy use. The impact on washer optimization was also considered, and net energy and chemical costs were reduced by US$3.8 and US$6.8/a.d. metric ton for a typical brown and bleach mill, respectively, when incorporating this technology. Completed in less than 12 months, the facility has demonstrated successful black liquor concentration at the 500 gpm scale with monthly uptime as high as 96%.

Energy and emission implications of optimized white liquor causticity, TAPPI Journal January 2026

ABSTRACT: Optimizing the causticizing plant offers significant opportunities for energy and emissions savings in kraft mills by minimizing the chemical and water deadload introduced into the recovery cycle via white liquor. Modern control strategies utilize both feedforward and feedback loops to manage causticity, enabling more aggressive targets closer to equilibrium levels. This paper evaluates the benefits of optimizing white liquor chemistry through a detailed CADSIM Plus simulation model, replicating the chemistry of a Canadian bleached kraft mill that adopted an automated causticizing control system. The control system increased causticity from 77.0% to 82.3% at a fixed total titratable alkali (TTA) of 126.5 grams of sodium dioxide per liter (gNa2O/L). Modeling this chemistry change indicated a 1.5 metric tons per hour (t/hr) reduction in evaporator steam demand and a 2.8% increase in black liquor higher heating value. Consequently, the improved heating value resulted in a 1.5% rise in recovery boiler steam production and a 5.3% reduction in biomass energy consumption in power boilers, leading to a 4.8% decrease in biogenic carbon dioxide (CO2) emissions. Additionally, reducing the inorganic and water deadload throughout the recovery cycle may support higher as-fired dry solids targets, enhancing recovery boiler energy efficiency by lowering the water evaporation requirement during black liquor combustion. However, implementing a causticizing control system requires careful assessment of potential lime kiln bottlenecks, as increased causticity demands may affect kiln operations depending on broader mill conditions. Overall, an automated causticizing control system enhances process efficiency, reduces energy consumption and emissions, and positions kraft mills for improved productivity and longterm sustainability.

Point load measurements on paperboard packages and bulging, TAPPI Journal March 2026

ABSTRACT: Paperboard packaging is made by processing board materials into sheets or rolls and shaping them through creasing, cutting, folding, and erecting. The conversion process generates residual moments at the folds that cause panel bulging. This study experimentally investigates how the bulging introduced during the converting processes influence the mechanical response of paperboard packages during point load testing within the elastic deformation range. The study shows that panel bulging may significantly affect packaging performance as-perceived strength and stiffness. Bulging, influenced by the board’s basis weight, can affect the package performance even more than packaging stiffness. Point load tests in the elastic region were performed on empty packages (78 mm × 50 mm × 110 mm) with force applied at specific points along their long sides. The packages evaluated in this study were made of two identically processed materials of different grammages. The heavier material showed more pronounced bulging than the lighter one, leading to overlapping force-displacement curves for the packages, and to that, a lower force and stiffness may be measured at a certain indentation depth for the package of heavier material. This complicates material choice according to functional requirements. The results show that a highly bulged package might resemble one with less bulging of another material. According to the results, it is not certain that a higher grammage package shows a higher indentation force and stiffness than a lower grammage package when measured at a certain indentation. This indicates that optimizing the creasing and folding processes can be a way to enhance performance rather than simply increasing board weight. The study underscores the importance of controlling converting parameters, especially creasing and folding behavior. Well-performed creasing and folding gives a low residual momentum, little bulging, and a high stiffness and compression strength at point loading in the elastic region. Proper optimization can improve packaging performance and manual handling user-friendliness.

Functionalization of wood/plant-based natural celluslose fibers with nanomaterials: a review, TAPPI JOURNAL February 2018

Functionalization of wood/plant-based natural celluslose fibers with nanomaterials: a review, TAPPI JOURNAL February 2018

Print quality of flexographic printed paperboard related to coating composition and structure, TAPPI Journal January 2018

Print quality of flexographic printed paperboard related to coating composition and structure, TAPPI Journal January 2018

Evaluation of the out-of-plane response of fiber networks with a representative volume element model, TAPPI JOURNAL June 2018

Evaluation of the out-of-plane response of fiber networks with a representative volume element model, TAPPI JOURNAL June 2018