Co-pyrolysis of palm kernel shell and polypropylene for the production of high-quality bio-oil: product distribution and synergistic effect.

Co-pyrolysis of palm kernel shell (PKS) with polypropylene (PP) was conducted in a fixed-bed reactor. The effects of pyrolysis temperature (400‒700 °C) and biomass:plastic ratio (0‒100%) on product quantity and quality as well as synergism during co-pyrolysis were investigated. Feedstock characterisation results showed that PKS and PP were able to produce sustainable liquid fuel and chemical. The highest bio-oil yield of 67.65 wt% was obtained at 600 °C and PKS:PP ratio of 25:75. A substantial amount of the desired compounds (60.12%) was obtained consisting of hydrocarbons (37.49%) and alcohols (22.23%). Positive synergistic effects on the production of hydrocarbons and esters, as well as the inhibition of acids and ketones, were prominent at 500 °C and PKS:PP ratio of 75:25. The plausible reaction mechanism for formation of major products was proposed. Co-pyrolysis of PKS and PP has generated bio-oil with a larger hydrogen and carbon content and lower oxygen composition compared to PKS bio-oil. Additionally, the resultant bio-oil has a slightly higher calorific value (47.74 MJ/kg) than the calorific value of commercial diesel fuels (46 MJ/kg), thus, offering an alternative for fuel applications. [ABSTRACT FROM AUTHOR]