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Energy saving potential of interstage screen fractionation for production of board grade BCTMP, TAPPI Journal August 2023
ABSTRACT: Over the last few decades, the continuing decline in mechanical pulp-based grades has led pulp producers to modify operations and implement measures to reduce production costs in order to stay competitive. In spite of a considerable effort to reduce energy consumption, the latter is still a major portion of production costs in the process of making bleached chemithermomechanical pulp (BCTMP). In this study, we evaluated the impact of interstage screening fractionation (ISSF) and secondary refining strategy for producing BCTMP with the objective of reducing refining energy consumption while maintaining or improving bulk and strength properties. In the first step and to establish a baseline for a mill’s existing configuration, the collected primary refined pulp and reject streams from the ISSF were refined in a high consistency (HC) refiner to target freeness levels. The accepts and refined rejects streams were recombined, and their properties were compared to those of the refined primary pulp. The results showed that, at a given freeness of 400 mL and compared to the control case (without fractionation), the ISSF using an 0.070 in. basket followed by rejects refining could lead to about 25% energy saving in the second stage HC refining. Handsheet properties showed that utilization of ISSF could produce BCTMP with higher bulk and similar average fiber length and tear index. However, a slight reduction in tensile strength was observed. In the second set of trials, the primary refined pulp and the rejects from the ISSF using the 0.070 in. basket were refined by a low-consistency (LC) refiner. The results showed that, at the same freeness of 400 mL and compared to refined primary pulp, the ISSF saved about 26% in net LC refining energy. At a specific edge load (SEL) of 0.4 J/m, the produced pulp had similar bulk and strength properties compared to those of the control sample. A higher SEL of 0.6 J/m in LC refining could further decrease net refining energy consumption; however, it also led to reduction in fiber length, bulk, and strength properties.
Journal articles
Magazine articles
A three-dimensional model of fine particle retention during
A three-dimensional model of fine particle retention during percolation through a fiber mat, TAPPI JOURNAL August 2015
Journal articles
Acid methanolysis: An analytical tool for estimating the proportions of different pulp types in deinked pulp or recovered paper, TAPPI JOURNAL August 2013
Acid methanolysis: An analytical tool for estimating the proportions of different pulp types in deinked pulp or recovered paper, TAPPI JOURNAL August 2013
Journal articles
ABSTRACT: This study investigates the impact of pulp screening on oxygen delignification of high lignin content kraft pulps from spruce wood. An alternative process is proposed: terminating kraft cooking at higher kappa numbers and applying oxygen deligni
ABSTRACT: This study investigates the impact of pulp screening on oxygen delignification of high lignin content kraft pulps from spruce wood. An alternative process is proposed: terminating kraft cooking at higher kappa numbers and applying oxygen delignification directly to unscreened and non-defibrated pulp. The objective is to evaluate whether this non-standard approach can maintain delignification efficiency while improving yield and reducing energy input. The findings demonstrate that screening prior to oxygen delignification is not essential for effective lignin removal or pulp quality. Similar delignification degrees and ISO brightness levels were obtained after oxygen delignification, whether it was performed on screened or unscreened pulps. Notably, the delignification rate in the oxygen stage was the same for the non-standard procedure as for pulp from the standard procedure with the reject fractionremoved prior to the oxygen stage. No significant differences were seen in fiber morphology, brightness level, orbrightness stability. The amount of total fiber charges in pulps not screened before oxygen delignification was slightly higher than in screened pulps.
Journal articles
ABSTRACT: Lignin’s potential as a source of sustainable aromatic compounds is significant, but its utilization is currently limited by its chemical reactivity. Chemical reactivity of lignin depends on the present functional groups, such as hydroxyl, metho
ABSTRACT: Lignin’s potential as a source of sustainable aromatic compounds is significant, but its utilization is currently limited by its chemical reactivity. Chemical reactivity of lignin depends on the present functional groups, such as hydroxyl, methoxy, and carbonyl groups. Therefore, in this study, multivariate analysis-based chemometric models have been developed for rapid determination of aliphatic hydroxyl (Alp-OH) and phenolic hydroxyl (Ph-OH) groups in lignin samples. Two chemometric models, principal component regression (PCR) and partial least squares regression (PLSR), were established with Fourier transform infrared spectroscopy (FTIR) spectral data of 28 lignin samples. Both the models were developed based on raw and pretreated spectroscopic data with Savitky-Golay (S-G) filtering and standard normal variate (SNV) and multiplicative scatter correction (MSC). The predictive performance of the PLSR model is better for predicting Alp-OH (R2 = 0.94%), syringyl-OH (R2 = 0.96%), guaiacyl-OH (R2 = 0.98%), p-hydroxyphenyl (R2 = 0.93%), and total Ph-OH groups (R2 = 0.97%) with the data pretreated by MSC. Finally, the predicted results of these parameters for three new samples for the developed models are found to be very close to the estimated values by NMR.
Journal articles
Effect of pulp refining on thixotropy of cellulose fiber suspensions, TAPPI Journal September 2025
ABSTRACT: This paper presents results on the thixotropic behavior of low-consistency bleached eucalyptus fiber suspensions that had been mechanically treated. The pulps were refined in a PFI mill at different numbers of revolutions (0, 3000, and 6000) to study the effect of refining intensity on the viscosity time-response of fiber suspensions. In steady rheological tests, all the suspensions exhibited shear thinning behavior and no significant differences were observed after mechanical treatment. Stepwise experiments showed that viscosity continuously increased with time when shear rate was suddenly reduced. Additionally, a delay in time evolution of viscosity was observed as the pulp was more refined. A stretched exponential model was fitted to the experimental results of viscosity.
Journal articles
Effects of biopolymer coatings on paper permeability and capillarity for paper-based rapid diagnostic test devices, TAPPI Journal September 2025
ABSTRACT: Rapid diagnostic test (RDT) devices are widely used for diagnostics due to their affordability, portability, and user-friendliness. However, conventional assays typically rely on nitrocellulose membranes and plastic casings. These materials raise environmental concerns due to their non-renewable nature, energy-intensive production methods, and poor biodegradability. This study explores the development of fully bio-based RDT substrates using a sustainable alternative: softwoodderived microfibrillated cellulose (MFC), cellulose nanocrystals (CNC), and chitosan as surface modifiers to improve paper properties and enhance RDT sustainability. Cotton filter paper substrates were coated with different biopolymer formulations using a manual blade coater: bleached MFC (BMFC), lignin-containing MFC (LMFC), BMFC combined with CNC, LMFC combined with CNC, and chitosan. Evaluation of the most relevant physical properties concerning RDT performance was conducted, including wetting, water retention value, air permeability, capillary flow rate, and surface morphology. Results showed that biopolymer- based coatings can effectively modify surface properties by reducing pore size and tuning hydrophilicity, while maintaining the renewable and bio-based characteristics of the substrate. The LMFC-coated paper exhibited the best overall performance among all formulations, reducing flow time by 50% (3.00 mm/s vs. 1.5 mm/s) compared to the uncoated paper, yet preserving high water retention. The BMFC+CNC coating also significantly improved flow rate, showing a 36.7% reduction (2.37 mm/s vs. 1.5 mm/s), and enhanced porosity uniformity. In contrast, the flow rate of chitosan-coated paper decreased by over 5,000% (0.027 mm/s), reflecting its strong barrier properties and hydrophobic surface (highest contact angle: 91.4°). These findings suggest that MFC-based coatings are promising ecofriendly alternatives to nitrocellulose, offering optimized capillary transport and structural adaptability. This paves the way for the development of sustainable, high-performance, rapid diagnostic tests.
Journal articles
Toward environmental resilience in pulp and paper manufacturing: Water consumption and carbon dioxide emission reductions, TAPPI Journal September 2025
ABSTRACT: Pulp and paper manufacturing is a water- and energy-intensive industrial sector, necessitating improvement of its operational efficiency, as well as reduction of emissions to the maximum extent possible. This review focuses on the reduction of water consumption and carbon dioxide (CO2) emissions that originate in the pulp and paper industry (PPI). First, process simulation and optimization techniques used for water consumption reduction are reviewed. Then, techno-economic analyses of solvent-based CO2 capture from PPI are discussed. Additionally, key actions are proposed for enhancing water consumption reduction and CO2 capture in PPI.
Journal articles
Editorial: Advancing barrier science and protective materials: The 2025 winners of TAPPI Journal Best Research Paper Award and Honghi Tran Prize, TAPPI Journal April 2026
At the end of each year, the TAPPI Journal Editorial Board Members nominate papers for consideration as recipient of the Best Research Paper and Honghi Tran Prize from that year, looking for outstanding contributions that push the science and engineering boundaries of fiber-based materials. For 2025, the Board nominated 10 papers and evaluated each nomination in terms of scientific merit, innovation, creativity, and clarity. After voting on the papers earlier this year, the Editorial Board chose two co-winning papers for this distinct honor.
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.