Bio-energy generation from sagwan sawdust via pyrolysis: Product distributions, characterizations and optimization using response surface methodology

Present work demonstrates the pyrolysis of sagwan sawdust for the production of bio-oil and biochar. Thermal degradation characteristics of sawdust by thermo-gravimetric analyzer revealed different zones of degradation. The effects of temperature, nitrogen flow rate and packed bed height were observed and optimized using response surface methodology with Box-Behnken design. For both cases, the quadratic model proved non-linear behaviour of the model response. Co-efficient of determination (R2) value for bio-oil and biochar yield was 0.9905 and 0.9975, respectively justifying excellent fitting of the model. Optimum yield (bio-oil and biochar) were obtained as 48.7083 and 25.5627 wt. %, respectively at the temperature of 640 °C, packed bed height of 8 cm and nitrogen flow rate of 180 mL/min. Presence of various organic compounds and chemicals were confirmed by GC-MS, FTIR analysis and physicochemical analysis described the fuel characteristics. Also, biochar was characterized by proximate and ultimate analysis, HHV, BET, FTIR and SEM-EDX. The above results revealed the utility of bio-oil as engine fuel or source of valuable chemicals. The HHV, porous nature of biochar along with high BET surface area and valuable nutrients indicates its utility as solid fuel, as an adsorbent or in soil amendment. •Optimization of pyrolysis process variables was done using response surface methodology (RSM).•Characterization for pyrolysis products was assessed by using advanced analytical techniques.•Bio-oil contained various chemicals and can be used as an alternative fuel after upgradation.•Biochar can be used as biocatalyst in process industry or may be as good adsorbent.