Catalytic deoxygenation by H2-free single-step conversion of free fatty acid feedstock over a Co-Ag carbon-based catalyst for green diesel production

A family of activated carbon-supported Co-Ag catalysts, synthesised through incipient wetness impregnation, have been evaluated for the deoxygenation of palm fatty acid distillate (PFAD) and inedible feedstocks (jatropha oil and waste cooking oil) to green diesel. High deoxygenation efficiency and conversion of PFAD to hydrocarbon liquid products through decarboxylation/decarbonylation (deCOx) is observed, with Co(10wt.%)-Ag(5− 20wt.%)/AC exhibiting the greatest hydrocarbon (C8–C20) fractions yield of 92 % and 95 % (C15+C17) selectivity after 120 min reaction at 350 ◦C. These results suggested the synergistic effect between the active metals, Co-Ag, and the activated carbon support, creating acid-base Bronsted ¨ sites, which significantly facilitated the selective deCOx pathway of the fatty acid. The catalyst Co(10wt.%)-Ag(10wt.%)/AC was capable of deoxygenation the PFAD over eight cycles. Thus, it can be believed a potentially promising catalyst for the production of green diesel, at the same time providing economic opportunities and added value to the palm oil industry

A promoter effect on hydrodeoxygenation reactions of oleic acid by zeolite beta catalysts

In this study, various metal-modified zeolite beta-based catalysts such as La(10)zeo(90), Co(10)zeo(90), Fe(10)zeo(90), Mg(10)zeo(90), Mn(10)zeo(90) and Zn(10)zeo(90) were investigated in the hydrodeoxygenation (HDO) of oleic acid (OA) to produce renewable diesel. The La(10)zeo(90) catalyst showed a conversion of OA up to 99 % with 83 % C15 and C17 selectivity after the reaction at 350 ◦C for 2 h under 4 MPa H2 pressure. The superior activity of La(10)zeo(90) was attributed to the synergistic interaction between La-Si-Al, a sufficient amount of weak+ medium acid sites and excellent textural properties (large pore diameter). Larger pore diameter of La(10)zeo(90) is highly desirable as it will generate greater diffusion of bulky molecules, thereby improving the accessibility of the reactant and hence excellent catalytic activity. The vacuum distillation was used to purify the crude liquid product (CLP), producing high-quality diesel fractions mainly comprising C14, C15, and C17 fractions

Hydrodeoxygenation of oleic acid for effective diesel like hydrocarbon production using zeolite based catalysts

This study investigated the hydrodeoxygenation (HDO) of oleic acid (OA) that is abundantly found in palm oil for the production of renewable diesel. The effectiveness of mesoporous catalysts, HZSM-5 and zeolite beta, in favoring diesel hydrocarbons was determined. The catalysts were activated by calcination at 550 °C for 5 h and their physicochemical properties were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed desorption using ammonia probe molecules (TPD-NH3), and Brunauer–Emmett–Teller analysis (BET). XRD analysis of both zeolite beta and HZSM5 showed high crystalline size of 24 and 84 nm, respectively. BET analysis found that the zeolite beta catalyst had a greater surface area (648 m2 g−1) than HZSM5 (465 m g−1) without significant differences in pore size and volume. According to the TPD-NH3 study, zeolite beta had the most weak medium acid sites when compared to HZSM5. It should be noted that HZSM5 also demonstrated the presence of strong acid sites. The optimal conditions for both catalysts were 350 °C, 4 MPa hydrogen pressure, and 5% catalyst load over a 2 h reaction period. From the results, the zeolite beta exhibited superior HDO reaction activity than HZSM5 with diesel selectivity~77%

One-pot decarboxylation and decarbonylation reaction of waste cooking oil over activated carbon supported nickel-zinc catalyst into diesel-like fuels

In this work, green diesel was generated via one-pot decarboxylation/decarbonylation (deoxygenation) reactions over a series of Ni20Znx/AC (X: 5–20 wt%) catalysts. The Ni20Zn10/AC catalyst exhibited superior deoxygenation reaction by yielding 86% hydrocarbons and 79% of n-(C15 + C17) selectivity, with the activity tending to undergo the decarbonylation pathway. Indeed, high deoxygenation activity is correlated with a higher acidity and basicity strength of the catalyst, and the removal of the oxygenates species occurred via decarbonylation pathways. The Ni20Zn10/AC catalyst showed a promising catalytic longevity and recyclability up until four runs, with a hydrocarbon yield of 78–87% and n-(C15 + C17) selectivity within the range of 43–70%. The decrease in the n-(C15 + C17) selectivity at the fourth cycle was due to leaching of active metal and the coking activity. The fuel properties of the green diesel (G100) were investigated, and it was revealed that the green diesel almost exhibited outstanding fuel properties (acid value, kinematic viscosity, flash point, cetane index, and calorific value) in comparison with ultra-low sulfur diesel (ULSD), suggesting that G100 can be used in vehicle engines without modification and has great potential for commercialization