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Non-process elements in the recovery cycle of six Finnish kraft pulp mills, TAPPI Journal March 2023
ABSTRACT: In this work, the aim was to study the distribution and accumulation of the non-process elements (NPEs) in the recovery cycle of Finnish pulp mills and look at whether the geographical location (North vs. South) correlates with the current Finnish NPE levels. In addition, a comparison to older similar Finnish measurements was made with an attempt to analyze the reasons behind differences in the most typical non-process elements, aluminum (Al), silicon (Si), calcium (Ca), phosphorus (P), magnesium (Mg), manganese (Mn), chlorine (Cl), and potassium (K), taking into account the main elements in the white liquor, sodium (Na) and sulfur (S). The extensive laboratory results gained in this study are from seven sampling points at six pulp mills and present analytical data of metal concentrations. The data obtained presents an update to previous NPE studies. The levels found did not statistically differ between North and South Finland. The NPE levels, apart from phosphorus, found in Finnish pulp mills today have not changed considerably compared to the levels in earlier investigations in the 1990s. In the newest data, the phosphorus concentration was consistently higher in the as fired black liquor, electrostatic precipitator (ESP) ash, lime mud, and green liquor than in the previous results. In addition, the levels of Al, Si, Ca, P, and Mg in recovery boiler ESP ash were consistently higher compared to the older results. As the mills start to close their systems more, a stronger accumulation of NPEs can be expected, increasing the likelihood of more operational problems in the process. Further understanding of where the NPEs accumulate and how they can be most effectively removed will be valuable knowledge in the future.
Journal articles
Magazine articles
Paper bending stiffness and web tension measurement from a running web using a vacuum and computer imaging, TAPPI Journal May 2023
ABSTRACT: A novel method for measuring the bending stiffness of paper online during manufacturing is introduced. The method uses photometric stereo imaging to detect the shape of the deflection surface caused by a controllable pressure difference over the paper’s surfaces. The hardware for the measurement is based on a combination of two existing sensors, which has accelerated and facilitated the development of the implementation. The deflection and loads are tied together by the governing differential equation for the bending of an orthotropic elastic plate with selected simplifications. An approach to resolve material parameters and in-plane loads without knowledge of traditional boundary conditions is suggested. The presented method was tested in a paper mill during manufacturing. For bending stiffnesses measured online, correlation coefficients 0.88 and 0.92 were obtained compared to state-of-the-art laboratory measurements. However, the results gained from a moving web are noisy and the data requires correction of the slope and an off-set. Although several issues remain to be resolved before the method can be considered as an accurate measurement for industrial use, the theoretical background, the performance of online implementation, and the results are promising. Possible causes for the observed discrepancies and the future development of the method are discussed.
Journal articles
Application of Spherical Hollow Calcium Carbonate Particles
Application of Spherical Hollow Calcium Carbonate Particles as Filler and Coating Pigment, 2002 Coating Conference Proceedings
Journal articles
Case Histories of Three Yankee Cracking Incidents Associated
Case Histories of Three Yankee Cracking Incidents Associated with Shell Edge Extensions, 1991 Engineering Conference Proceedings
Journal articles
Theoretical Drying Study of Single-Tier Versus Conventional
Theoretical Drying Study of Single-Tier Versus Conventional Two-Tiered Dryer Configurations, 1992 Engineering Conference Proceedings
Journal articles
Application of Imaging Reflectometry to Studies of Print Mottle on Commercially Printed Coated Papers, TAPPI JOURNAL January 2008
Application of Imaging Reflectometry to Studies of Print Mottle on Commercially Printed Coated Papers, TAPPI JOURNAL January 2008
Journal articles
Applications of tension and nip load profile measurement using a novel roll mounted electret film sensor, TAPPI JOURNAL April 2010
Applications of tension and nip load profile measurement using a novel roll mounted electret film sensor, TAPPI JOURNAL April 2010
Journal articles
Effects of impregnation time on hardwood kraft pulp characteristics and papermaking potential â?¢ a mill study, TAPPI JOURNAL April 2010
Effects of impregnation time on hardwood kraft pulp characteristics and papermaking potential • a mill study, TAPPI JOURNAL April 2010
Journal articles
Starch-modified fillers for linerboard and paper grades: A perspective review, TAPPI JOURNAL April 2010
Starch-modified fillers for linerboard and paper grades: A perspective review, TAPPI JOURNAL April 2010
Journal articles
CFD-Based Modeling of Kraft Char Beds â?¢ Part 2: A Study on the Effects of Droplet Size and Bed Shape on Bed Processes, TAPPI JOURNAL February 2010
CFD-Based Modeling of Kraft Char Beds • Part 2: A Study on the Effects of Droplet Size and Bed Shape on Bed Processes, TAPPI JOURNAL February 2010