LIQUEFACTION OF COFFEE BIOMASS WITH RESIDUAL GLYCERIN: A STUDY OF RENEWABLE FUEL PRODUCTION

Abstract

The present study analyzes the hydrothermal liquefaction of residual coffee biomass using glycerin from the production of biodiesel through the homogeneous route. The reactions occurred by varying the glycerol/water ratio (1:0, 1:1, and 1:2) and the solvent/biomass ratio (70 and 90%) with heating at 180°C for 30 minutes (mixing phase) and at 250°C for 15 minutes. The products obtained were identified as light bio-oil (BOL), heavy bio-oil (BOP), gaseous fraction (FG), and solids (SOL). These products were submitted to characterization through density, thermogravimetry, and viscosity analyses. The condition that generated the highest oil yields was the one where 70% solvent and a glycerin/water ratio of 1:2 were used, producing approximately 83% of bio-oils. In this perspective, coffee biomass and residual glycerin were suitable for use in the hydrothermal liquefaction process.