EFFECTS OF TORREFACTION TEMPERATURE AND RESIDENCE TIME ON AGRICULTURAL RESIDUE AFTER PELLETIZATION PROCESS: CORNCOBS/ CORNHUSKS, RICE STRAW, AND SUGARCANE TRASH
Keywords:
Torrefaction, biomass, corncobs, cornhusks, pellets, rice straw, sugarcane trashAbstract
Agricultural residues have a low bulk density, which requires larger storage space and higher transport costs compared with wood and other types of fuels. However, agricultural residues could be utilized as solid fuel by transforming them into biomass pellets, which would increase their bulk density. Furthermore, technology such as the torrefaction process could be applied in order to enhance the heating values of the biomass pellets. The effects of the torrefaction temperature and residence time (RT)on the moisture content (MC), density, volatile matter (VM), ash, fixed carbon (FC), heating value, mass yield (MY), and energy yield (EY) of selected agricultural residues, comprising corncobs/ cornhusks, rice straw, and sugarcane trash, after pelletization were studied. The MC of all the torrefied pellets was lower than 2%wt (wet basis), while the ash, FC, and heating value tended to increase with the increase of the temperature and RT for all types of residues. The density, VM, MY, and EY tended to decrease, probably because of the exothermic reaction occurrence, resulting in hemicellulose decomposition into a char-like solid product and volatiles, which oxygenated and hydrogenated the compounds. In conclusion, pelletization before torrefaction could be considered as the most appropriate approach for further development because a low temperature and short processing time are required, there is a reduced area for storage after production, and the quality of the product is high.
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