Thermal behaviors and kinetics for fast pyrolysis of chemical pretreated waste cassava residues

In the present study, thermal decomposition behaviors and kinetics for fast pyrolysis of acid/alkali pretreated waste cassava residues were investigated. The results demonstrated that chemical pretreatments apparently loosened the compact structure of cassava residue and benefited to the sufficient contact with acid/alkali sites. Acid/alkali pretreatments enriched the product varieties and had remarkable influence on the adjustment of product formation. Particularly, the pyrolysis behavior obviously shifted to low-temperature zones for pretreated samples. Low heating rate significantly promoted the formation of anhydrosugars with 27% levoglucosan produced, while elevating heating rate contributed to furfural production. Some oxygenated-chemicals, such as acetic acid, hydroxyacetone and 4-hydroxydihydrofuran-2(3H)-one, were apparently formed in the presence of alkali metal. Noticeably, the generation of most gaseous products was restrained for those acid-impregnated cassava residues. Moreover, kinetic study suggested that the apparent activation energy for waste cassava residue pyrolysis was significantly lowered, further verifying the positive role of chemical pretreatments. (C) 2020 Elsevier Ltd. All rights reserved.