Journal of Engineering Research and Reports

The increasing shift into sustainable fuels and its global demand necessitates integrating biomass derivatives into petroleum refineries as a viable strategy for renewable fuel production. This study investigated the catalytic co-pyrolysis of coconut shell with vacuum gas oil (VGO) in a fixed-bed reactor at 550 °C and a catalyst-to-feed ratio of 1:3 (w/w). Coconut shells were obtained from market dumps, processed and characterized for its proximate, calorific value (HHV) and ultimate composition. Crude bio-oil obtained via fast pyrolysis of coconut shell and further cracked with VGO was characterized using Gas Chromatography-Mass Spectrometry (GCMS) and Fourier Infrared Transform Spectroscopy (FTIR). The physiochemical properties of the bio-oil in terms of viscosity, acid value, saponification value, specific gravity, ester value and pH were determined. Bio-fuel (upgraded oil) obtained through fluid catalytic cracking with vacuum gas oil was analysed to determine the density, pH, refractive index, pour point, flash point, viscosity. The bio-fuel functional groups was determine using (FTIR). Response Surface Methodology (RSM) were used to develop the bio-oil and bio-fuel yield among the considered factors; (particle size, heating temperature and holding time and reaction temperature) and (temperature, time, reactor riser and dosage mixture) respectively. The proximate, calorific value (HHV) and ultimate analysis of the coconut shell, was determined as follows: moisture content 7.67%, volatile matter 66.1%, ash 1.4%, fixed carbon 24.8%, HHV 4339.85 kcal/kg, carbon 56.43%, hydrogen 4.16%, oxygen 37.51%, and nitrogen 0.48%. The crude bio-oil exhibited a viscosity of 12.7 cP, saponification value of 332.39 mg KOH/g, ester value of 192.14 mg KOH/g, and acid value of 140.25 mg KOH/g, demonstrating suitability but high oxygenate content. GC-MS identified dominant compounds including phenol, p-cresol, 2-methoxyphenol, methyl paraben, cresol, and 2,6-dimethoxy-4-(2-propenyl)phenol, consistent with lignocellulosic pyrolysis products. FTIR of the upgraded oil (Bio-fuel) revealed reduced oxygenated functional groups such as ketones, phenols and enriched hydrocarbons such as alkanes, aromatic ethers, confirming effective deoxygenation and aromatization. The upgraded oil physicochemical properties was determined as follows: density 1.05 g/cm³ at 30°C, pH 3.12, refractive index 1.51, pour point -20°C, flash point 150°C, and viscosity 1.46 cP. Experimental yields for bio-oil were 62.35 wt% (particle size 1.5 mm, heating 500 °C, holding 60 min, reaction 550 °C), and for biofuel 70.12 wt% (temperature 500–532°C, time 300–228 min, riser 30–38 inches, dosage 0.5–0.78). This co-processing approach demonstrates potential for producing refinery-compatible bio-fuel with improved stability and energy density.