Catalytic pyrolysis of Reutealis trisperma oil using raw dolomite for bio-oil production

Conversion of non-edible Reutealis trisperma Oil (RTO) into bio-oil by catalytic pyrolysis was carried out using dolomite as catalysts. Dolomite, a sedimentary carbonate rock mineral, has shown potential as a cheap and eco-friendly catalyst to enhance bio-oil yield by reducing coke formation. Dolomite was directly used in the catalytic pyrolysis of RTO without prior calcination or treatment. Increasing the pyrolysis temperatures from 400 °C to 450 °C, improved bio-oil production from 59.68% to 77.39%, with only 0.11% of carbon char formation. The non-catalytic thermal pyrolysis produced 68.29% liquid bio-oil product and 7.04% carbon char. GC-MS analysis revealed that dolomite also enhanced the composition of heavy hydrocarbon molecules, contributing to a higher flash point and thermal stability of bio-oil. Analysis of the physical properties proved that the use of fresh dolomite decreased the viscosity (3.12 cSt) and increased calorific value (41.61 MJkg−1) and density (0.85 g/cm−3) compared with the bio-oil produced by non-catalytic thermal pyrolysis. Bio-oil quality was further enhanced through esterification reaction that significantly reduced the carboxylic acid content from 55.47% to 3.32%.