Characterization of products from slow pyrolysis of palm kernel cake and cassava pulp residue

Slow pyrolysis studies of palm kernel cake (PKC) and cassava pulp residue (CPR) were conducted in a fixed-bed reactor. Maximum liquid yield (54.3 wt%) was obtained from PKC pyrolysis at 700 °C, heating rate of 20 °C/min, N₂ gas flow rate of 200 cm³/min and particle size of 2.03 mm. Fuel properties of bi-oils were in following ranges: density, 1.01–1.16 g/cm³; pH, 2.8–5.6; flash point, 74–110 °C and heating value, 15 MJ/kg for CPR oil and 40 MJ/kg for PKC oil. PKC oil gave main contents of n-C₈–C₁₈ carboxylic acids, phenols, and esters, whereas CPR oil gave the highest amount of methanol soluble fraction consisting of polar and non-volatile compounds. On gas compositions, CPR pyrolysis gave the highest yield of syngas produced, while PKC pyrolysis offered the highest content of CO₂. Pyrolysis chars possessed high calorific values in range from 29–35 MJ/kg with PKC char showing a characteristic of reasonably high porosity material.