Search
Use the search bar or filters below to find any TAPPI product or publication.
Filters
Content Type
Publications
Level of Knowledge
Committees
Collections
Journal articles
Magazine articles
Low-temperature precausticizing — a hopeful approach for green liquor desilication, TAPPI JOURNAL February 2017
Low-temperature precausticizing — a hopeful approach for green liquor desilication, TAPPI JOURNAL February 2017
Journal articles
Magazine articles
Operating parameters affecting the thermal performance of bi
Operating parameters affecting the thermal performance of biomass boilers, TAPPI JOURNAL August 2017
Journal articles
Magazine articles
Drying characteristics of biosludge from pulp and paper mill
Drying characteristics of biosludge from pulp and paper mills, TAPPI Journal August 2017
Journal articles
Magazine articles
Effects of lignin chemistry on oxygen delignification performance, TAPPI JOURNAL July 2018
Effects of lignin chemistry on oxygen delignification performance, TAPPI JOURNAL July 2018
Journal articles
Magazine articles
The solubility of calcium carbonate in green liquor handling systems, TAPPI Journal October 2019
ABSTRACT: The formation of hard calcite (CaCO3) scale in green liquor handling systems is a persistent problem in many kraft pulp mills. CaCO3 precipitates when its concentration in the green liquor exceeds its solubility. While the solubility of CaCO3 in water is well known, it is not so in the highly alkaline green liquor environment. A systematic study was conducted to determine the solubility of CaCO3 in green liquor as a function of temperature, total titratable alkali (TTA), causticity, and sulfidity. The results show that the solubility increases with increased temperature, increased TTA, decreased causticity, and decreased sulfidity. The new solubility data was incorporated into OLI (a thermodynamic simulation program for aqueous salt systems) to generate a series of CaCO3 solubility curves for various green liquor conditions. The results help explain how calcite scale forms in green liquor handling systems.
Journal articles
Magazine articles
Comparing a linear transfer function-noise model and a neural network to model boiler bank fouling in a kraft recovery boiler, TAPPI Journal, July 2024
ABSTRACT: Boiler bank fouling reduces heat transfer efficiency in kraft recovery boilers. Here, we model the relationships between boiler parameters and boiler bank pressure drop, an indicator of fouling, based on recovery boiler operating data. We compared two models: an autoregressive integrated exogenous (ARIX) model and a feedforward neural network. The ARIX model better simulates boiler bank pressure drop compared to the neural network (R2 of 0.64 vs. 0.58). Based on the ARIX model, we identified six boiler parameters that significantly influence boiler bank fouling and their relative contributions. Finally, we demonstrate how the models can simulate boiler bank pressure drop given artificial perturbations in boiler parameters.
Journal articles
Magazine articles
Rheological behavior of magnetic pulp fiber suspensions, TAPPI Journal June 2021
ABSTRACT: This paper is focused on the rheology of magnetic pulp suspensions in absence and presence of an external magnetic field. Magnetic fibers were prepared by the lumen loading method using bleached eucalyptus fibers and cobalt ferrite (CoFe2O4) nanoparticles. The effect of mass consistency, temperature, concentration of magnetic fibers, and magnetic field strength on yield stress and apparent viscosity of the suspensions were investigated. In the absence of an applied field, a dependence of yield stress with consistency, as well as with the percentage of magnetic fibers present in the suspension, was found. In flow tests, all the suspensions exhibited shear-thinning behavior, showing that the viscosity is only affected by the consistency of the suspension. On the other hand, magnetorheological measurements show a negative effect of the applied magnetic field on the viscosity of the suspension.
Journal articles
Magazine articles
Continuous tannin extraction by use of screw reactor, TAPPI Journal February 2021
ABSTRACT: A pilot-size screw reactor (extraction unit) was used for tannin extraction of spruce. Yield of the same magnitude or better was obtained when comparing a screw reactor with batch reactors. A longer presoaking time in water seemed to be better than a short one for obtaining higher yield. A higher yield is obtained with lower dry-water ratio, which suggests that the internal diffusion in bark does not determine mass transfer as much as is the case without presoaking of bark. The higher dry-water ratio decreased the yield. The prior soaking of the bark also minimized the mechanical reactor feeding problems (clogging). The benefits of a screw reactor likely are that run time changes for different process conditions are flexible; it simplifies design and construction of an industrial unit for tannin production; and it saves space because of the need for fewer and smaller intermediate storage tanks.
Journal articles
Magazine articles
New learnings and strategies for meeting future recovery boiler particulate emission limits with existing electrostatic precipitators, TAPPI Journal June 2021
ABSTRACT: It is foreseeable that recovery boiler particulate emission limits in the United States and Canada will continue to get more stringent with time. Because of this, continued improvement of emission control equipment, as well as a better understanding of how operating parameters affect performance, are necessary. Although electrostatic precipitators (ESPs) are often viewed as a mature technology, many improvements in ESP technology continue to be developed. In recent years, academic efforts have improved the understanding of recovery boiler operating conditions on ESP performance. Additionally, advancements in materials, power supplies, and design continue to improve the efficiency and reliability of ESPs.This paper discusses how recovery boiler and electrostatic precipitator (ESP) operating factors affect ESP perfor-mance based on process simulations and practical experience, and how these learnings can be implemented to improve future operation of existing ESPs.
Journal articles
Magazine articles
New opportunities in the paper and nonwovens industries with foam-assisted web forming and chemical application, TAPPI Journal January 2023
ABSTRACT: Foam-assisted web forming and chemical application technologies have great potential to improve manufacturing efficiency and product quality in the paper and nonwovens industries. In this study, the benefits of foam forming and foam-assisted application of chemicals were demonstrated in a pilot machine trial. Uniform high-bulk webs of unrefined bleached softwood kraft pulp (BSKP) and viscose fibers were manufactured by foam forming. It was shown that foam formed low-grammage and high-bulk viscose fiber webs can be strengthened by foam-assisted application of latex onto the wet web. Correspondingly, foam-assisted application of carboxymethyl cellulose (CMC) and anionic polyacrylamide (A-PAM) improved the strength of the foam formed low-grammage and high-bulk BSKP web. Overall, the pilot machine results indicated that material cost savings could be achieved and a high-performance product could be manufactured with foam-based technologies.