Production of green transportation fuels from Brassica carinata oil: A comparative study of noble and transition metal catalysts

Abstract

Herein, we present the production of jet and diesel range hydrocarbons from non-edible hexane-extracted Brassica carinata oil. The influence of four heterogeneous catalysts (two noble metal catalysts: Pd/C and Ru/C, and two transition metal catalysts: Ni/C and Ni/SiO2-Al2O3) was investigated at 400 °C. The catalysts were characterized using XRD, Raman spectroscopy, TEM, SEM, TGA, TG-TPR, and BET specific surface area and pore size analyzer. The upgrading experiments consisted of three different approaches: 1) single-step cracking (1-C), 2) single-step simultaneous cracking, and hydrotreatment (1-C·H), and 3) a two-step process of cracking followed by hydrotreatment (2-C·H). Reaction products were characterized using different instruments and metrics: GC-FID, GC–MS, simulated distillation, CHNS-O elemental analyzer, viscometer, higher heating value (HHV), and total acid number (TAN). The 2-C·H process produced the highest amounts of desired hydrocarbons. The highest liquid yield of 81% with HHV of 47 MJ/kg was obtained with the use of Ni/SiO2-Al2O3 catalyst. All catalysts appeared to be regenerable after partial deactivation. Model compound studies were performed using erucic acid that accounted for about 40% of carinata oil FFA (free fatty acid) profile. Reaction pathways were proposed according to the chemical analysis of the products.