Conversion of cassava rhizome to alternative biofuels via catalytic hydrothermal liquefaction

Abstract

In this study, cassava rhizome was converted to alternative biofuels including biocrude oil (BO) and hydrochar (HC) using catalytic hydrothermal liquefaction (C-HTL) at 250 and 300℃ for 15 min using 4.0 wt.% of K2CO3 as a catalyst. BO and HC properties were investigated regarding the parameters of elemental composition, chemical functional groups, chemical compositions, and surface morphology. The maximum energy recovery efficiency (ERE) of sum product (83.98 wt.%) was derived at 300℃. Therefore, 300℃ was suggested as a promising C-HTL temperature. This condition derived a yield of BO and HC at 33.70 and 33.29 wt.%, with their Higher heating value (HHV) at 26.45 and 18.81 MJ/kg, respectively. Gas chromatography-mass spectroscopy (GC-MS) analysis results indicated that BO principally contains phenols, aldehydes and ketones, hydrocarbons and alcohols which can be fractionated and upgraded into the biofuels and various valuable chemicals. The hydrogen/carbon (H/C) and oxygen/carbon (O/C) atomic ratios of BO and HC were similar to those of fossil fuel, indicating their high potential as fossil fuel substituting materials.