Effects of constant and staged torrefaction temperatures on biomass combustion and pyrolysis
Proceedings of the Australian Combustion Symposium 2021
The Combustion Institute
School of Engineering
Torrefaction is a thermal pre-treatment method used to enhance the thermochemical, hydrophobic, and grindability properties of raw biomass. It is typically undertaken in an inert or oxygen deficient environment. In this study, the sensitivity of woody biomass fuels to two types of heating commonly reported in torrefaction research were investigated. Biomass fuel, in the form of 6.5 mm pellets torrefied at 300 °C was subjected for 30 minutes in a tube furnace to either a (i) (sudden) “constant heating” or a (ii) “staged heating” involving a gradual ramp-up. This paper analyses torrefied fuel properties through TGA (and indictor of thermochemical properties) and an immersion testing method (to assess hydrophobicity). Thermogravimetric profiles highlighted the elimination of hemicellulose and the decrease in the cellulose fraction in both torrefied samples from (i) and (ii). However, the extent of degradation in holocellulose fraction of biomass was much higher in samples torrefied using (ii) staged heating compared to (i) constant heating. Furthermore, staged heating also showed better hydrophobicity than the latter. The overall results highlight the need for research (into torrefied biomass) to also report the temporal evolution of heating when studying torrefaction due to its apparent effect on the overall properties of biomass.
Riaz, S., & Al-Abdeli, Y. (2021). Effects of constant and staged torrefaction temperatures on biomass combustion and pyrolysis. In Proceedings of the Australian Combustion Symposium 2021.