Characterization of the optimal catalytic pyrolysis conditions for bio-oil production from brown salwood (Acacia mangium Willd) residues

Abstract

Fast growing trees have recently attracted interest as a possible feedstock for bio-energy because they are environmentally friendly and provide a sustainable energy source. This work demonstrated the production of bio-oil and related chemicals by the catalytic pyrolysis of brown salwood (Acacia mangium Willd) residue in a continuous pyrolysis reactor using 1.00 wt % of dolomite catalyst. The effects of temperature (440–580 °C), biomass feed rate (0.3–0.9 kg h−1), and nitrogen gas flow rate (80–160 cm3 min−1) and their reciprocal interaction were determined; these parameters were adjusted systematically to optimize the experimental design using Box-Behnken design. Response surface methodology based on 3 levels of experimental design was used to determine the parameters that affected the production of bio-oil and the product distribution. The optimum conditions were determined to be a reaction temperature of 540 °C, a biomass feed rate of 0.45 kg h−1 and a nitrogen gas flow rate of 155.00 cm3 min−1 with a constant amount of 1.0 wt% dolomite catalyst. We obtained a maximum bio-oil yield of 44.78 ± 0.47 wt% through the use of response surface methodology. The modified quadratic regression model revealed the optimal application of temperature and feed rate in accordance with the residence time; meanwhile, the nitrogen gas flow rate was also considered. The bio-oil was characterized using GC-MS, FTIR, and physicochemical and elemental analyses. Brown salwood residues were shown to be applicable to thermal processes, and catalytic pyrolysis was shown to be a potential candidate to produce bio-oil and value-added chemicals for several applications. © 2017 Elsevier Ltd