Synergetic effect of biomass mixture on pyrolysis kinetics and biocrude-oil characteristics

Biocrude-oil characteristics were investigated from fast pyrolysis of a mixture of Douglas fir and coffee ground. The mixture was prepared on a 1: 1 weight basis and pyrolyzed in a bubbling fluidized bed reactor. Characteristics of biocrude-oil were compared at various reaction temperatures ranging from 673-873K. The mixture resulted in a more improved quality biocrude-oil than each biomass feedstock at the reaction temperature of 823 K with significantly low atomic ratio of 0.43 O/C. The kinetic parameters for biomass decomposition were investigated through Friedman, KAS, FWO and CC isoconversional models. In mixture pyrolytic conversion range of 0.1-0.8, the average activation energy was found to be 135 kJ/mol. The results showed that pyrolysis of coffee ground with Douglas fir has more synergetic effect than individual biomass, which leads to a potentially higher quality fuel with lower activation energy to that of biomass.