Pyrolysis of three waste biomass: Effect of biomass bed thickness and distance between successive beds on pyrolytic products yield and properties

In the present study, the effect of biomass bed thickness and distance between successive beds on pyrolytic products yield were carried out. Sawdust of pine wood and sal wood, as well as husk of areca nut, were used as a biomass feedstock. To achieve maximum liquid yield, 500 °C temperature, 80 °C min⁻¹ heating rate, 0.5 mm particle size and 100 mL min⁻¹ gas flow rate was selected as optimum conditions. An equal amount of biomass was placed in six different bed arrangements while dividing the amount of biomass equally among the number of beds as well as keeping an equal distance between the successive beds. Further, the entire reactor was fitted inside the furnace so as to distribute the heat uniformly throughout the rector which also signified that each biomass bed has the same thermal profile at any time. It was found that liquid properties were better (lower viscosity, higher heating value) at fourth bed arrangement than in other bed arrangements. FTIR and GC-MS analysis confirmed the presence of aromatic, phenol, ester, ether, alcohol, acid, and amide groups. Gas chromatography also confirmed that with increasing temperature, the amount of hydrogen and hydrocarbons increased significantly while the formation of CO₂ was reduced.