Fast pyrolysis of coffee grounds: Characteristics of product yields and biocrude oil quality

The high demand of renewable energy has been growing nowadays due to shortage of fossil fuels and global warming. The studies on fast pyrolysis of biomass were mostly in progress by using woody biomass, to investigate characteristics of biocrude oil and optimum conditions of fast pyrolysis. Currently a variety of biomass have been used for sample material of fast pyrolysis to produce biocrude oil. In particular, coffee grounds are expected to be a valuable energy source because of consumption growth of coffee and higher heating value than woody biomass. In the present experiment, coffee grounds were chosen as feedstock for fast pyrolysis. The objective of this work was to study the characteristics of product yields and biocrude oil quality depending on reaction temperatures ranging from 673 K to 873 K. Also, higher heating value, water content, viscosity, pH, density, ash, and solid residue of the collected biocrude oils were analyzed. From the result, the reaction temperature is the most important variable in fast pyrolysis of coffee grounds, significantly influencing the product yields. The highest yield of biocrude oil (54.85%) was obtained at 823 K. Also, the characteristics of biocrude oil were scrutinized by variations of experimental conditions.