Comparative study of bio-oil production from sugarcane bagasse and palm empty fruit bunch: Yield optimization and bio-oil characterization

Abstract

This research focused primarily on the process optimization for bio-oil production in a pilot-scale batch reactor operating in a fixed bed and using two important agricultural residues from Santander Department in Colombia: sugarcane bagasse (SB) and palm empty fruit bunch (EFB). The Simplex method was applied to develop experimental tests in which three main variables were studied: temperature, gas residence time and particle size. The choice of such variables was based on literature review suggesting that they have a major influence on bio-oil yield. The ranges of the operating conditions were: temperature 460–600°C, gas residence time 16–80s and particle size 0.5–1.4mm. The analysis of variance (ANOVA) shows the temperature being the most influential variable on the bio-oil yield. The other variables were not significant for bio-oil production from intermediate pyrolysis. In the case of SB, the best operating conditions (temperature 560°C, gas residence time 77s and particle size 0.5–0.85mm) resulted in a bio-oil yield of 53.4wt%, whereas in the case of EFB, the best operating conditions (temperature 540°C, gas residence time 31s and particle size <0.5mm) resulted in a bio-oil yield of 48.4wt%. However, the physical–chemical properties of bio-oil stemming from the two studied biomasses are completely different, where the bio-oil from EFB presents the best HHV of 34.91MJ/kg, the highest pH (3.9) and the lowest density (approximately 958kg/m3).