PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 7, Number 2, 2021
the paper containing HCC, higher solid content was achieved with still better stiffness, smoothness, and tensile strength in comparison with the paper containing GCC. Actually, very high bulk of the HCC containing paper was compromisingly reduced to obtain high solid content by applying higher wet pressing pressure. Higher solid content achieved by combination of HCC technology and higher wet pressing pressure resulted in paper drying energy savings of more than 10%, while a high quality of all the essential printing paper properties was maintained. Drying energy savings may contribute to greenhouse gas (GHG) reduction and lowering of the paper production cost. “ Analysis and control of the paper moisture content variability by using fuzzy and traditional individual control charts ” , José L.Rodríguez-Álvarez, Rogelio López- Herrera, Iván E. Villalon-Turrubiates, Rey D. Molina-Arredondo, Jorge L. García- Alcaraz & Óscar D. Hernández-Olvera, Chemometrics and Intelligent Laboratory Systems , Vol.208, 15 January 2021. For several decades, the fuzzy theory has been used to develop the so-called fuzzy control charts to analyze process data in a more reliable and flexible way than traditional control charts. Control charts are more commonly used in the papermaking processes to check the stability of the data source. These charts are conceived as devices that enhance routine time-by-time adjustments during the production process, so their value is incomparable. A critical variable that must be controlled during the papermaking process is the moisture content of the paper. However, due to the paper’s hygroscopic characteristics, it s moisture content values may carry some uncertainty derived from measurement systems and the nature of the papermaking process. Therefore, an alternative approach that includes fuzz control charts to handle these uncertainties is proposed in this paper. The method to convert individual data to fuzzy numbers is based on the sigma level process as a first stage, and then, the fuzzy individual and moving range control charts are introduced using the cut fuzzy midrange approach. Data from the moisture content of a 240 g coated paper sample is used to prove the performance of the fuzzy individual control charts. According to the proposed methodology, findings show that fuzzy individual and moving range control charts have greater flexibility than traditional individual control charts by reflecting a larger amplitude of their control limits, in addition to a lower number of “out of control” values. “ Recycling cellulose nanofibers from wood pulps provides drainage improvements for high strength sheets in papermaking ” , Shaun Ang, Debjani Ghosh, Victoria Haritos & Warren Batchelor, Journal of Cleaner Production , Vol.312, Online, 20 August 2021. The recyclability of cellulose nanofibers (CNF) is one of its most promising features. However, the performance of recycled CNF is not fully established. In this work, we engineered CNF sheets from refined and homogenized industrial virgin pulp (BEK), industrial recycled pulp (DIP) and lab-scale recycled pulp (LRC). These original CNF sheets were then soaked and recycled using a standard disintegrator to produce recycled CNF sheets. The key changes with recycled CNF sheet properties were tracked and compared to their original CNF sheets. Fiber retention and sheet uniformity measurements revealed a higher proportion of fiber aggregates with original CNF from DIP and LRC, compared to BEK. The proportion of fiber aggregates increased even further with recycled CNF. These results are consistent with the well-established formation of strong irreversible hydrogen bonds which hinder complete refibrillation. The tensile index of original 10K1P (10,000 PFI revolutions refined and 1 high-pressure homogenized pass) CNF sheets made from recycled DIP and LRC fibers at 110 Nm/g was only 10% lower compared to those made from virgin BEK fibers. Interestingly, all recycled CNF sheets from homogenized fibers successfully retained about 80% of their original CNF sheet strength. Remarkably, all recycled CNF sheets also had significant reductions in sheet drainage
Technical Abstracts
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