Thermal catalytic cracking of crude palm oil at pilot scale: Effect of the percentage of Na2CO3 on the quality of biofuels

• Study of thermal catalytic cracking at a pilot scale (reactor of 143 L).
• Acid value decreased as the sodium carbonate percentage increased.
• The GC–MS analysis showed that OLPs comprise a low level of oxygenates.
• The OLPs have physical–chemical properties and chemical composition similar to those of petroleum diesel.
• The optimal sodium carbonate catalyst percentage was found to be 15% (w/w).

In this study, the influence of catalyst content on the physical–chemical properties, yield, and chemical composition of organic liquid products (OLP) obtained by thermal catalytic cracking of palm oil (Elaeis guineensis, Jacq.) was studied at a pilot scale. The experiments were carried out in a reactor of 143 L, running in batch mode at 450 °C and 1 atm, using 5%, 10%, 15%, and 20% (w/w) Na2CO3 as the catalyst. Physical–chemical characterization of OLP was conducted for acid value, saponification value, specific gravity, refractive index, kinematic viscosity, copper strip corrosion, and flash point. The chemical composition of OLP was determined by gas chromatography–mass spectrometry (GC–MS). As the catalyst content increased, the kinematic viscosity of OLP decreased from 6.59 to 3.63 mm2 s−1 and the acid value from 51.56 to 1.26 mg KOH/g. The GC–MS analysis showed that OLP comprise hydrocarbons (normal paraffin, olefin, and naphthenic) and oxygenated compounds (carboxylic acids, alcohols, ketones, and esters), with a high dependency on the catalyst level. As the catalyst content increased, the concentration of hydrocarbons increased, whereas the concentration of oxygenates decreased. The optimal sodium carbonate catalyst level was found to be 15% (w/w). This gave the highest rate of conversion into biofuel, of which around 60% was OLP, and produced biofuels with the lowest acid values. The physical–chemical properties were within the limits fixed by ANP No. 65 (Diesel S10 specification) due to their high hydrocarbon content (92.84%) and low oxygenate content (7.16%). The hydrocarbons produced had characteristics similar to those of petroleum diesel, offering the potential to replace petroleum fuels without requiring deacidification or deoxygenation pretreatment.