Carbon dioxide-assisted Torrefaction of Maize Cobs by Thermogravimetry: Product Yield and Energy Recovery Potentials


  • Bemgba B. Nyakuma Benue State University
  • Samuel-Soma M. Ajibade Universiti Teknologi Malaysia
  • Victor B. Adebayo Malaysian-Japan International Institute of Technology, Universiti Teknologi Malaysia
  • Habib Alkali University of Maiduguri
  • Victor O. Otitolaiye Department of Health Safety & Environmental Management, International College of Engineering & Management, Seeb, Oman.
  • Jemilatu O. Audu Modibbo Adama University of Technology
  • Faizah M. Bashir University of Hail
  • Yakubu A. Dodo Istanbul Gelisim University
  • Abubakar S. Mahmoud King Fahd University of Petroleum and Minerals
  • Olagoke Oladokun Covenant University



Carbon dioxide, Torrefaction, Maize Cobs, Thermogravimetry, Energy Recovery


The objective of this study is to examine the potential product yields and energy recovery of maize cobs (MC) through carbon dioxide-assisted torrefaction using thermogravimetric analysis (TGA). The CO2-assisted torrefaction of MC was performed from 240 °C to 300 °C (Δ 30 °C) for the residence time of 30 minutes based on the selected non-isothermal/isothermal heating program of the TGA. Furthermore, the physicochemical, microstructure and mineral characteristics of MC were examined. The results showed that the CO2-torrefaction of MC resulted in a mass loss (ML) ranging from 18.45% to 55.17%, which resulted in the mass yield (MY) ranging from 81.55% to 44.83%. The HHV of the solid product was in the range from 22.55 MJ/kg to 26 MJ/kg, which indicates the CO2-torrefaction process enhanced the energy content of MC by 40% – 60%. In conclusion, the findings showed that the CO2 torrefaction is a practical, sustainable, and cost-effective approach for the valorization of MC into a clean solid biofuel for enhanced energy recovery.

Author Biography

Habib Alkali, University of Maiduguri

Department of Agricultural & Environmental Engineering, University of Maiduguri, Maiduguri, Borno State, Nigeria.


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How to Cite

Nyakuma, B. B., M. Ajibade, S.-S. ., Adebayo, V. B. ., Alkali, H., Otitolaiye, V. O. ., Audu, J. O. ., … Oladokun, O. (2022). Carbon dioxide-assisted Torrefaction of Maize Cobs by Thermogravimetry: Product Yield and Energy Recovery Potentials. Physics and Chemistry of Solid State, 23(1), 16–24.



Scientific articles (Physics)