An investigation of catalytic hydrocracking of high FFA vegetable oils to liquid hydrocarbons using biomass derived heterogeneous catalysts

• MBCUS and BBTPFS were utilized as hydrocracking catalysts.
• CaO present in BBTPFS accelerates the decarboxylation pathways.
• Novelty of these materials as hydrocracking catalysts.
• Heavy and precious metal catalysts substitutes.
• More than 65% hydrocarbon products recovery.

Catalytic hydrocracking of high free fatty acid (FFA) containing Mesua ferrea L. and Jatropha curcas oil (triacylglycerol) was investigated using biomass derived heterogeneous catalysts viz. Musa balbisiana Colla underground stem (MBCUS) nanomaterial and biomass based thermal power plant fly ash (BBTPFS). Reactions were studied in a batch mode in a bench scale reactor at 400 °C under variable initial H2 pressure (1–75 bar) for 1–4 h using 1–5 wt.% catalysts loading. Our results confirm that the reaction network consisted of multiple pathways leading to a product mixture rich in hydrocarbons, non-polar oxygenates and organic acids commonly known as biocrude. Decarboxylation, hydrolysis, hydrocracking and thermocatalytic cracking appeared to be the dominating reactions subsequently leading to the production of hydrocarbon mixture of chain length C8–C19. The resultant biocrude was fractionated into four fractions within the boiling range 35–140 °C, 140–180 °C, 180–370 °C and 370–482 °C as per ASTM D2892 and ASTM D5236 specifications. Further, the recovery in each fraction was directly affected by biocrude quality which in-turn was dependent upon catalyst properties and reaction conditions. The reaction networks were also varied significantly with respect to reaction atmosphere and as well as for the two catalysts which directly affected the yield and quality of product (higher heating value, acidity index, liquid distillate recovery etc). To summarize, BBTPFS was found to be a more effective catalyst for acidity and heteroatom removal, and consequently, produced biocrude with lowest acidity and highest percentage (≥65%) of the product in the liquid hydrocarbon range.