PRODUCTION OF GREEN DIESEL BY HYDROCRACKING OF CANOLA OIL ON Ni-Mo/γ- Al2O3 AND Pt-ZEOLITIC BASED CATALYSTS^

摘要

As an alternative way to produce biodiesel, the hydrocracking of canola oil was studied on different types of catalysts. Experiments were carried out in a batch reactor over a temperature range of 300 to 400°C, initial hydrogen pressure of 5 to 11MPa, and reaction times 1 to 6 hours. Three types of bifunctional catalysts were developed and used: Pt/H-Y zeolite, Pt/HZSM-5 and sulfided NiMo/γ- Al2O3. At the conditions studied, the hydrocracking on Ni-Mo/γ- Al2O3 catalyst gave the highest conversion to liquid hydrocarbons in the boiling range of diesel fraction. The Pt-zeolite catalysts revealed a strong catalytic activity for both cracking and hydrogenation reactions, and therefore initial high hydrogen pressures were found to be required to reach a good conversion. The time of reaction was limited in observance of the rates of reaction for both hydrogenation and cracking reactions, which strongly depended on the type of catalyst. In most cases, the GC analysis of the gaseous phase revealed the presence of mainly CO2, CO, propane, and hydrogen. Oxygen was not present. The hydrocracking of canola oil on a NiMo/Al2O3 catalyst produced a diesel fraction mainly composed of normal paraffins from C15 to C18. Traces of unconverted fatty acids and a very low amount of water were also detected. After evaluation of the composition and physical properties of the liquid product, they were found to be very similar to those of petro diesel, but with the advantage that the former contains a higher percentage of C17 and C18 hydrocarbons, and therefore a higher cetane number.^