Energy & Fuels, Vol.32, No.2, 1812-1821, 2018
Production of Hydrotreated Jatropha Oil Using Co-Mo and Ni-Mo Catalysts and Its Blending with Petroleum Diesel
Jatropha oil is a prospective non-edible resource for green diesel manufacturing. In this work, diesel-range hydrocarbons (mostly C-15-C-18 n-paraffins) were produced from the hydrotreatment of jatropha oil over traditional CoMo/Al2O3 and NiMo/Al2O3 catalysts in a fixed-bed reactor. The reaction variables were varied as follows: temperature, 563-653 K; pressure, 1.5-3 MPa; H-2/oil ratio, 200-800 (v/v); and weight hourly space velocity, 1-4h(-1). Oil conversion was maximized (Co-Mo, 97%; Ni-Mo, 88.6%) at T = 653 K and P = 3 MPa. The hydrocarbon yield at these conditions was 62.6% (Co-Mo) and 63% (Ni-Mo). These findings were juxtaposed with our latest results on the hydrotreatment of the non-edible karanja oil. From the first-order plots of conversion of triglycerides in jatropha oil, rate constants and energy of activation were found. To improve the cold flow properties of the hydrotreated jatropha oil without isomerization, it was blended with usual diesel in varying proportions. As the concentration of usual diesel in such mixtures increased, the viscosity, cetane number, and pour point decreased. Employing tailored blends of hydrotreated vegetable oil and petroleum diesel thus appeared preferential. Finally, the performance of Co-Mo and Ni-Mo catalysts prepared by wet impregnation was tested, but the activity of the commercial catalysts was superior.