The effect of biomass bulk arrangements on the decomposition pathways in the torrefaction process

This paper investigated the effects of biomass bulk arrangements on their decomposition pathways. In addition, the higher heating value and surface morphology of torrefied biomass received from two different arrangements, hollow and compact bulk, was observed. The investigation was conducted at torrefaction temperature of 250, 270, and 290 degrees C and a residence time of 60 min. The evidence from weight loss curves, SEM images, higher heating values, and numerical simulation confirmed that the difference in bulk arrangements contributed to different decomposition pathways. The hollow bulk arrangement contributed to a decomposition pathway which can be described by using the two-step reaction in series model. The compact bulk arrangement resulted in an autocatalytic decomposition pathway and a higher level of decomposition. This increasing level consequently led to a higher value of the higher heating value compared to that of the hollow bulk arrangement. (C) 2015 Elsevier Ltd. All rights reserved.