Box Behnken design application for optimization of bio-oil yield from catalytic pyrolysis of agro-residue

Abstract

A Response Surface Methodology (RSM) was used to investigate the effect of reaction temperature and biomass to catalyst (b/c) ratio on the catalytic pyrolysis of three wood sawdust samples in a fixed bed reactor using Green zeolite-Y catalyst synthesized from Ficus exasperate (L.) leaf particles. Temperature (400–700 °C), biomass percentage (60–100%), and catalyst (0–40%) were the independent variables with a total of 15 experimental runs, including 3 center runs, were generated via the Box-Behnken experimental design. The results reveal that biomass/ catalyst (b/c) ratio of 80/20% at 550 °C yielded optimum pyrolytic liquid for Melicia excelsa (Me), Diospyros crassiflora (Dc) and Entada Africana (Ea) as 31 wt.%, 31 wt.%, 30 wt.%, respectively while with the attendance of catalysts at 20% increased the yield of pyrolytic liquid for Me (45 wt.%), Dc (42 wt.%), and Ea (43 wt.%). GCMS analysis of Me (80.81 wt.%), Dc (73.96 wt.%), and Ea (70.26 wt.%) pyrolytic oil reveals the dominance of phenols, ethers, alcohols, ketones, alkanes, and acids. Reduction in acidity, decrease in oxygen content, increase in viscosity of the bio-oil were noticed in biomass/catalyst (b/c) ratio of 80/20 at 550 °C. These measurements show enhanced pyrolysis oil characteristics, which is a boost to its bioenergy potential.