Biomass torrefaction characteristics in inert and oxidative atmospheres at various superficial velocities.
The reaction characteristics of four biomass materials (i.e. oil palm fiber, coconut fiber, eucalyptus, and Cryptomeria japonica) with non-oxidative and oxidative torrefaction at various superficial velocities are investigated where nitrogen and air are used as carrier gases. Three torrefaction temperatures of 250, 300, and 350 °C are considered. At a given temperature, the solid yield of biomass is not affected by N2 superficial velocity, revealing that the thermal degradation is controlled by heat and mass transfer in biomass. Increasing air superficial velocity decreases the solid yield, especially in oil palm fiber and coconut fiber, implying that the torrefaction reaction of biomass is dominated by surface oxidation. There exists an upper limit of air superficial velocity in the decrement of solid yield, suggesting that beyond this limit the thermal degradation of biomass is no longer governed by surface oxidation, but rather is controlled by internal mass transport.
Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan, ROC. Electronic address: weihsinchen@gmail.com.
Wei-Hsin
WH
Chen
Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC.
Ke-Miao
KM
Lu
Iron and Steel Research and Development Department, China Steel Corporation, Kaohsiung 812, Taiwan, ROC.
Shih-Hsien
SH
Liu
Iron and Steel Research and Development Department, China Steel Corporation, Kaohsiung 812, Taiwan, ROC.
Chi-Ming
CM
Tsai
Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC. Electronic address: wjlee@mail.ncku.edu.tw.
Wen-Jhy
WJ
Lee
Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC.
Ta-Chang
TC
Lin
D000388:Air; D001272:Atmosphere; D056804:Biofuels; D018533:Biomass; D003059:Cocos / Q000378:metabolism; D032485:Cryptomeria / Q000378:metabolism; D005052:Eucalyptus / Q000378:metabolism; D005740:Gases; D006358:Hot Temperature; D007700:Kinetics; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D000073878:Palm Oil; D010938:Plant Oils / Q000737:chemistry; D013696:Temperature
D056804:Biofuels; D005740:Gases; D010938:Plant Oils; D000073878:Palm Oil; D009584:Nitrogen; D010100:Oxygen
Energy yield; Fibrous and ligneous biomass; Heat and mass transfer; Non-oxidative and oxidative torrefaction; Superficial velocity