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Journal articles
Magazine articles
Open Access
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
Open Access
Editorial: AI in Higher Education: Implications for scholarly publishing, TAPPI Journal September 2026

Even as we grapple with the positive and negative implications of artificial intelligence (AI), it has become increasingly embedded in our personal lives and work, including higher education. A recent snapshot of AI’s impact in this area is the Digital Education Council’s (DEC’s) AI in Higher Education Global Survey 2026. Founded in early 2024 to study how AI and digital transformation impact higher education, learning, and workforce skills, DEC is made up of member institutions throughout the world in academia and vocational learning. It currently has more than 200 members in over 42 countries.

Journal articles
Open Access
Nonlinear modeling of batch digester discharge dynamics with rheology-driven hydraulic transport and drainability coupling, TAPPI Journal September 2026

ABSTRACT: Batch digester blowdown constitutes a strongly nonlinear transient transport process governed by the coupled evolution of pulp consistency, slurry density, hydraulic resistance, liquid inventory, and discharge line dynamics. A control-oriented nonlinear formulation is developed by coupling dry fiber and free liquor mass balances with phase volume reconstruction, consistency-dependent hydraulic resistance, channeling and drainability effects, and a power law head flow relationship derived within a lumped hydraulic inertance framework. A fixed-gain PI controller obtained from local linearization is employed as the conventional benchmark, whereas an integral sliding mode controller (SMC) explicitly compensates the nonlinear time-varying hydraulic structure and bounded disturbances. Both strategies are evaluated under identical actuator constraints and sequential perturbations involving opposing head, hydraulic resistance, channeling, drainability, and dilution. Numerical results demonstrate lower rootmean- square error, integral absolute error, and peak flow-tracking error for the SMC, with rapid recovery toward the prescribed sliding boundary layer and improved robustness to variations in the nonlinear flow exponent n. Cumulative electrical energy and batch-specific specific energy consumption remain comparatively similar, indicating that the principal SMC benefit is enhanced hydraulic regulation rather than substantial batch energy reduction. Specific energy consumption is an established metric for energetic assessment of slurry transport. Model-based hydraulic demand, electrical power, and sliding manifold surfaces further characterize the nonlinear operating domain. The resulting framework provides a computational proof-of-concept for modeling and control of transient batch digester discharge systems.

Journal articles
Open Access
Pressure drop characteristics of steam condensation flow in triangular channels for multi-channel cylinder dryers, TAPPI Journal September 2026

ABSTRACT: This study investigates the condensation pressure drop characteristics of steam in the channels of multi-channel drying cylinders, which remain insufficiently understood. An experimental system was established using a horizontal mini-channel with a triangular cross-section and a hydraulic diameter of 4.09 mm. Flow visualization combined with a high-precision data acquisition system was employed to systematically examine the effects of steam mass flux (10•60 kg/(m²·s)), inlet temperature (110°C•140°C), and cooling water flow rate (100•500 kg/h) on the frictional pressure drop during condensation. The results indicate that the two-phase frictional pressure drop increases with rising steam mass flux but decreases with increasing saturation temperature, while the effect of cooling water flow rate becomes more pronounced under lower temperature conditions. In addition, several existing two-phase flow pressure drop correlations were evaluated against the experimental data. Based on a comparative assessment of eight existing correlations, a new predictive model was developed through regression analysis, achieving a mean absolute percentage error (MAPE) of 19.56%. These findings elucidate the pressure drop mechanism of steam condensation in triangular channels and establish a high-precision predictive model, providing theoretical guidance and a critical tool for the engineering design and energy consumption optimization of multi-channel drying cylinders.

Journal articles
Open Access
Sintering of fireside deposits and its impact on plugging in kraft recovery boilers, TAPPI JOURNAL April 1988 88APR109

Sintering of fireside deposits and its impact on plugging in kraft recovery boilers, TAPPI JOURNAL April 1988

Journal articles
Open Access
Combined effect of fiber fines and dissolved organics on tissue properties, TAPPI JOURNAL April 1988 88APR141

Combined effect of fiber fines and dissolved organics on tissue properties, TAPPI JOURNAL April 1988

Journal articles
Open Access
The role of diffusion during initial delignification of alkaline pulping, TAPPI JOURNAL April 1988 88APR145

The role of diffusion during initial delignification of alkaline pulping, TAPPI JOURNAL April 1988

Journal articles
Open Access
Correlating the on-line measurement of ultrasonic velocity with strength properties, TAPPI JOURANL April 1988 88APR149

Correlating the on-line measurement of ultrasonic velocity with strength properties, TAPPI JOURANL April 1988

Journal articles
Open Access
Measurement of strains in a paper tensile specimen using computer vision and digital image correlation-Part 2: Tensile specimen test, TAPPI JOURNAL April 1988 88APR153

Measurement of strains in a paper tensile specimen using computer vision and digital image correlation-Part 2: Tensile specimen test, TAPPI JOURNAL April 1988

Journal articles
Open Access
88apr63

Retention, drainage, and formation on high-speed formers, TAPPI JOURANL April 1988

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