Pyrolysis of pine needles: Parameter optimization using response surface methodology

Pine needles are forest residue-based biomass abundantly available in the Uttarakhand state of India. The presence of stranded pine needles in the forest land causes fires. At the same time, switching from fossil resources to renewable ones is the need of the hour. Among the available biomass conversion technologies, pyrolysis is a well-established and commercialized process. Therefore, the pyrolysis of pine needles to produce bio-oil with high yield and quality could be the best option for a sustainable future. Central composite design-based response surface methodology was employed to design the experiments. The study involved optimizing the process parameters such as temperature, residence time, and gas flow rate. The maximum bio-oil yield of 38.1 wt% was achieved at 500 degrees C, 30 min, and 50 mL.min(-1) and the highest biochar yield of 60 wt% with a high heating value of 25.40 MJ/kg was obtained at 232 degrees C, 60 min, and 100 mL.min(-1).