Influence of the temperature in the yield and composition of the bio-oil from the pyrolysis of spent coffee grounds: Characterization by comprehensive two dimensional gas chromatography

Coffee is an important agricultural product being one of the most consumed beverages in the world. The goal of this work is to apply the pyrolysis to this residue for the production of bio-oil. The pyrolysis of the biomass (SCG) was done in a fixed bed reactor and varying the final temperature (400, 450, 500, 550 and 600 °C). The higher crude bio-oil yield was obtained at 500 °C with a flow of N2 in 100 mL/min (mass yield = 30.51%). The bio-oil produced by pyrolysis of SCG had its chemical composition analyzed by comprehensive two-dimensional gas chromatography coupled to mass spectrometry detector (GC × GC/TOF-MS) and associated with LTPRI. This bio-oil showed potential for the production of chemical and liquid fuels, evidencing to be a good option for the destination of this waste. Its composition showed high amount of phenols, fatty acids and nitrogen compounds. The major compounds in the bio-oil sample were n-hexadecanoic acid (palmitic acid) (19%), 9-octadecenoic acid (oleic acid) (11%), octadecanoic acid (stearic acid) (10%).