Insight into Co-pyrolysis of Palm Kernel Shell (PKS) with Palm Oil Sludge (POS): Effect on Bio-oil Yield and Properties

Bio-oil a carbon based liquid fuel from fast pyrolysis of biomass, can bring prospective changes in the renewable energy field gradually. However, the bio-oil ought to be upgraded since it possesses several negative attributes such as high corrosiveness, high acidity, and high content of water. Catalytic pyrolysis and co-pyrolysis are able to improve some of the properties of bio-oil during production. The fast pyrolysis of palm kernel shell (PKS) produces acidic bio-oil whereas the fast pyrolysis of palm oil sludge (POS) liberates basic bio-oil. Therefore, current study investigated the fast co-pyrolysis of PKS with POS at different blend ratios (10, 20, 35 and 50 wt% POS with PKS) with the aim to produce bio-oil with improved pH. The corresponding blends were pyrolyzed at 507 +/- 13 degrees C in a fixed bed reactor. As the amount of POS in the blends increased from 0 to 100 wt%, a negative synergistic effect (SP) was observed and so a decrease in bio-oil yield. The observation was attributed to the presence of AAEMs found in POS. The total acid number (TAN) of bio-oils decreased with increasing POS ratio in the blends as well. At PKS to POS mass ratio of 50:50, the pH value of the bio-oil produced was 4.6 +/- 0.1. Based on the yield and physical properties of bio-oil, the blend with 20 wt% of POS was chosen as the desired ratio as it yielded 40.8 +/- 3.7 wt% of bio-oil with a slight negative synergistic effect (SP) of 3.26.