Biodiesel from batch and continuous oleic acid esterification using zeolite catalysts

The esterification of oleic acid with ethanol was studied in both batch and continuous conditions in a fixed-bed reactor over FAU-type zeolites prepared from shale rock. The addition of Co-Ni-N to the zeolite increased the catalyst activity over the entire reaction temperature range. Experiments confirmed that esterification follows pseudo first-order kinetics. Thermodynamic analysis and Thiele modulus calculations show that the reaction is kinetically controlled in batch conditions, while diffusional limitations occur at higher flow rates when conducted in continuous mode. The maximum oleic acid conversions were recorded as 93% for batch and 89% for continuous, which exceed those of any analogous studies.