PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 10, Number 1, 2024
“Degrees of hornification in softwood and hardwood kraft pulp during drying from different solvents”, Mozhgan Hashemzehi, Björn Sjöstrand, Helena Håkansson & Gunnar Henriksson, Cellulose , Vol.31, 1813 – 1825, (2024). Hornification, a complex phenomenon occurring during drying of lignocellulosic materials because of formation of irreversible chemical bonds, remains a subject of scientific interest. This study aims to shed light on the underlying mechanisms of hornification by investigating interactions between the liquid and solid phases through a solvent exchange treatment. The treatment involved replacing water with various solvents in suspensions of never-dried cellulose samples, including alcohols (methanol, ethanol, isopropanol) capable of forming hydrogen bonds, albeit to a lesser extent than water, as well as non-alcohol solvents (acetone, ethyl acetate, toluene, heptane) that do not possess the ability to form chain of hydrogen bond, and no hydrogen bond between each other. The impact of solvents on the hornification process was evaluated using WRV measurements. Our findings reveal that water, as a solvent, plays a dominant role in the hornification process, primarily due to its excellent capability to form bridges of hydrogen bonds. In comparison, hornification with alcohols was considerably lower than with water, likely attributed to the smaller ability of alcohols to engage in such interactions. Furthermore, our results indicate a tendency for reduced hornification also when using non-hydrogen bond solvents with decreased polarity. This strengthens the hypothesis related to chains of hydrogen bonds. Additionally, the interaction between hydrophobic surfaces on cellulose through hydrophobic interactions could provide another plausible explanation. TISSUE “Life Cycle Assessment of Tissue Paper: Effects of Bioenergy Integration”, Ana Dias, Ricardo Carvalho, Cristina Marques, Raquel A. Bértolo, Ana M. Carta & Luís M. Machado, Pre-Print not peer-reviewed, ssrn.com. Globally, the use of tissue products such as toilet paper has been growing. One possible strategy to decrease greenhouse gas (GHG) emissions in tissue production is the integration in the same site of pulp and paper mills and their energy systems, to maximize slush pulp and bioenergy supply for paper production. However, the environmental trade-offs associated with this strategy are still unclear. This study aims to: i) assess the environmental impacts of tissue paper produced in a typical industrial site in Portugal using slush and market pulp as the main raw material, and ii) assess the effects of the integration of bioenergy produced in the pulp mill in tissue production through the quantification of GHG emission reductions and assessment of trade-offs in other environmental impact categories. For this purpose, a life cycle assessment was conducted from cradle-to-gate using real data from the production of eucalyptus wood, eucalyptus pulp, and tissue paper. The ReCiPe 2016 impact assessment method was applied as default and the Environmental Footprint (EF) method was used in a sensitivity analysis to ensure the robustness of the conclusions. The results show that energy consumption in tissue paper production is the main hotspot for most impact categories. When bioenergy is used in tissue production, the environmental impacts calculated with the ReCiPe and EF methods decrease up to 20% for categories other than marine eutrophication and mineral resource scarcity. In conclusion, bioenergy integration in tissue production not only enhances industrial decarbonisation but, in general, also contributes to reducing the environmental footprint of tissue products. These results are relevant to support decision-making not only for the pulp and paper industry but also for authorities in charge of defining environmental policies, incentives and tax regulations.
Technical Abstracts
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