Cassava Waste Torrefaction for Energy Purposes

Abstract

Biomass torrefaction consists of a heat treatment process that by slow heating of the material promotes the release of moisture and volatile constituents of low molecular weight. In this work, the objective was to carry out the torrefaction process in cassava rhizome in order to analyze its effect on the energy properties of the waste. The residue collected in natura was dried, ground and torrefied in two different forms: with granulated material and with material densified in briquettes; performing a torrefaction process at temperatures of 200 and 300 °C, with torrefaction time of 30 and 60 minutes. According to results, the cassava rhizome torrefaction can increase its initial high heating value of 16.3 MJ/kg from 21 to 51%, and decrease from 81% to 42% its volatile content; while torrefied briquettes showed little variation in their properties, except for the briquettes torrefied at 300 °C for 60 minutes. Therefore, when performing torrefaction of densified biomass, there is a need to use higher temperature and longer torrefaction time when compared to granular biomass.