Catalytic cracking of pyrolytic oil by using bentonite clay for green liquid hydrocarbon fuels production

Highlights: • Bentonite catalyst led to a considerable decrease in the oil yield (from 48.79 wt.% to 37.27 wt.%). • Upgraded pyrolytic oil yield of 37.27 wt.% was obtained at catalyst ratio of 30 wt.%. • Bentonite clay was effective on the organic compound group distributions of pyrolytic oil. • Upgraded oil had lower density and viscosity than those of pyrolytic oil. • Upgraded bio-oil was rich fine chemicals such as furfural, phenol, etc. The pyrolysis of almond shell as a biomass feedstock was performed in order to obtain a bio-based feedstock for bio-refineries in a fixed-bed reactor under inert atmosphere (occurred by N₂ gas) at certain experimental conditions including 500 °C of temperature and a heating rate of 10 °C min⁻¹. Then, the catalytic cracking of obtained pyrolytic liquid was conducted by using bentonite clay as a low-cost catalyst material at the conditions of 400 °C of temperature, a heating rate of 10 °C min⁻¹ and catalyst ratio of 30 wt%. The upgraded bio-oil revealed the properties of a basic fuel including 4.01 cSt of viscosity at the temperature of 40 °C; approximately 45.22% lower than that of non-upgraded bio-oil, low density of 1100.78 kg m⁻³ at 15.6 °C, H/C molar ratio of 1.413 and calorific value (HHV) of 26.92 MJ kg⁻¹. The results of the chromatographic and spectroscopic analysis of the obtained bio-oils have revealed that the presence of bentonite clay led to a considerable increase in some organic compound groups such as phenolic, ketones, and oxygenated aromatics.