Superheated steam as carrier gas and the sole heat source to enhance biomass torrefaction. (July 2021)

• Record Type: Journal Article
• Authors: Zhang, Dongdong; Chen, Xuejiao; Qi, Zhiyong; Wang, Hong; Yang, Rui; Lin, Wei; Li, Jie; Zhou, Wanlai; Ronsse, Frederik
• Is Part Of: Bioresource technology. Volume 331(2021)
• Publication Date: 2021-07
• Subjects: Superheated stream torrefaction -- Wood shavings -- Torrefied biomass as biocoal -- Production efficiency; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2021.124955
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Superheated steam torrefaction was proposed to upgrade biomass. Superheated steam torrefaction was comparable to slow pyrolysis process. Significant time saving was obtained by superheated steam torrefaction. Torrefied wood shavings increased HHV from 20.99 to 29.03 MJkg −1 . Abstract: Superheated steam (SHS) has been used as a carrier gas for pressurized steam torrefaction, steam explosion or pyrolysis, but is barely used as a heat source. However, SHS is superior in thermal capacity and heat transfer coefficient resulting in even heating and fast heating rates. Therefore, this work applied SHS as the sole heat source for torrefaction at ambient pressure. A setup was specially designed and capable of heating wood shavings at a rate >120 °Cmin −1 . Solid products were analyzed in many aspects and demonstrated the enhanced organics conversion owing to SHS torrefaction. Torrefied biomass was comparable to slow pyrolysis char in fuel quality and superior to that of conventional torrefactions. Moreover, SHS torrefaction was super-timesaving. A coal-like product (HHV of 27.84 MJkg −1 ) was achieved in only 15 min at 350 °C. Overall, SHS torrefaction boosted biomass densification and gave rise to greater production efficiency.