Structural and molecular modifications of woody biomass under minimal torrefaction conditions toward making durable pellets
Biomass and Bioenergy Research Group, Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, B.C., Canada.
Research Article
GSC Advanced Research and Reviews, 2024, 20(03), 129–138.
Article DOI: 10.30574/gscarr.2024.20.3.0341
Publication history:
Received on 02 August 2024; revised on 16 September 2024; accepted on 18 September 2024
Abstract:
Extensive research has been published on pelletizing severely torrefied biomass with the aid of binders, but limited studies have investigated the structural modifications of biomass during mild torrefaction. This study investigates the effects of several combinations of minimal torrefaction temperatures (230°C and 250°C) and relatively short durations (10, 15, and 30 minutes) on the thermophysical and molecular structure of the model woody biomass loblolly pine (Pinus Taeda) residues. The low severity treated biomass is compared with the untreated biomass and the biomass torrefied at 270°C for 30 minutes. Structural characterization methods include laser diffraction for particle size distribution and Brunauer-Emmett-Teller (BET) analysis to evaluate specific surface area. Additionally, FTIR, XRD, and TGA are used to assess changes in crystallinity and thermochemical composition. The woody residue torrefied at 250°C for 10 minutes exhibited a higher BET surface area (4.7 m²/g) than torrefied at 250°C for 15 minutes (3.5 m²/g). At a constant temperature of 250°C, the crystallinity index increases with the treatment duration, emphasizing the effect of time on retaining more hydroxyl groups that may act as binders for pelletization. This study demonstrates that minimizing the combination of torrefaction time and temperature can help control the degree of biomass molecular structure degradation thus minimizing overall mass loss, offering potential applications in the emerging biocarbon pellet industry.
Keywords:
Woody biomass; Minimal torrefaction; Binding properties; Molecular modification; Physical structure of particles
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Copyright © 2024 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0
