Influence of temperature on bamboo torrefaction under carbon dioxide atmosphere

• Published in: Industrial crops and products Vol. 76; pp. 149 - 157
• Main Authors: Li, Ming-Fei, Li, Xun, Bian, Jing, Xu, Ji-Kun, Yang, Sheng, Sun, Run-Cang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2015
• Subjects: Carbon dioxide; Energy yield; Hydrophobicity; Structural changes; Torrefaction; Torrefaction; Structural changes; Hydrophobicity; Energy yield; Carbon dioxide
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2015.04.060

[Display omitted] •Bamboo was torrefied under CO2 atmosphere at 240–340°C.•The effect of temperature on energy yield and structure was evaluated.•Element variation was shown in CHO ternary and van Krevelen diagrams.•High temperature resulted in substantial changes of bamboo structure.•Torrefaction reduced the absorbed moisture content. Bamboo was torrefied under carbon dioxide atmosphere at 240–340°C, obtaining solid products with mass yield 40.58–96.89%, energy yield 63.01–99.09%, and higher heating value 18.78–28.51MJ/kg. The solid products were characterized by FTIR, NMR, TG/DTA, and X-ray diffraction analysis. Under the severest torrefaction condition, cellulose and hemicelluloses were completely decomposed. From the initial bamboo to the heavily torrefied sample, C concentration increased but H and O concentrations decreased. A high temperature of 320°C yielded product having atomic H/C and O/C ratios in the region of lignite, and a higher temperature of 340°C produced torrefied sample with atomic H/C and O/C ratios in the region of coal. The hydrophobicity of torrefied bamboo was increased with the increase of torrefaction temperature. Results indicated that torrefaction under carbon dioxide was a promising process for the utilization of bamboo.