Upgrading of coconut shell-derived pyrolytic bio-oil by thermal and catalytic deoxygenation

Abstract

ABSTRACTThe objective of this study is to upgrade the pyrolysis oil obtained from coconut shells via thermal deoxygenation and catalytic hydrodeoxygenation (HDO) and compare the elemental properties of the upgraded bio-oil samples. The crude coconut shell pyrolysis oil (cr-CSPO) was obtained in 33% yield by intermediate pyrolysis (575°C) of pre-dried coconut shells. The higher heating value (HHV) of cr-CSPO was found to be 16.46 MJ/Kg. The thermal and catalytic upgrading was done at 250°C, 30 bar of hydrogen pressure, a reaction time of 3 h, and a stirring speed of 350 rpm. In the case of catalytic upgrading, 10% Pd/C (10 wt% of cr-CSPO) was used as the catalyst. Thermally heating the cr-CSPO under identical conditions without the catalyst provided oil of HHV 25.94 MJ/kg. Catalytic HDO of the cr-PCSO showed a noticeable increase in the HHV value to 30.57 MJ/kg. The results indicate significant improvement in the combustion properties of cr-CSPO by thermal treatment and more so by the catalytic HDO chemistry.