Catalytic pyrolysis of olive pomace for biofuel production: Application of metal oxide-modified zeolite catalysts

Abstract

Catalytic pyrolysis of olive pomace (OP) was studied in a quartz fixed bed reactor at 500 °C. Due to the presence of high amounts of oxygenated components (OC) in bio-oil, the aim of this research was upgrading of bio-oil to valuable biofuel. Synthesized MgO, CaO, NiO, and Co3O4 modified zeolite catalysts were examined at several catalysts to biomass (C/B) ratios (0.2, 0.3, 0.4, 0.5, and 5). Different characterization method including Brunauer–Emmett–Teller (BET) and N2 adsorption/desorption isotherm analysis, X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) were performed to identify the synthesized catalysts. Results showed that the bio-oil yield decreases in catalytic pyrolysis. All metal-modified zeolite catalysts reduce the content of OC as undesirable compounds and increase aromatic and aliphatic hydrocarbons as valuable products in the bio-oil. Using MgO, CaO, NiO and Co3O4 supported on zeolite catalysts, increase notably the aromatic hydrocarbons content to 82.43%, 79.10%, 79.91%, and 79.19%, respectively at C/B ratio of 5. At the C/B ratio of 5, the elimination rate of total OC for MgO/zeolite and CaO/zeolite catalysts reach to 90.56% and 86.94%, respectively. For NiO/Zeolite and Co3O4/zeolite, this value is equal to 89.30% and 86.39%, respectively.