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Waste oil, like waste cooking and acidic oil, are two promising carboxylic acids feedstocks that can be converted into hydrocarbons by the pyrolytic method, usually through DCO 2 and DCO processes. DFT is employed to investigate the deoxygenation mechanism using octanoic acid as a model compound in this work. Additionally, pyrolysis of the above samples was carried out at atmospheric pressure, temperature below 773.15K. GC-MS, GC and TG-FTIR-MS test measures were used to analyze pyrolytic products. The DFT results reveal that pyrolysis conversion of waste oil was a direct and effective deoxygenation method. And high alkene content endowing pyrolytic oil greatly potential to upgrade for high-quality biofuel production. Finally, pyrolytic oil was upgraded by SAPO-11-Pd/C can increase the components of iso-hydrocarbons, further can faction cut to obtain three biofuel fractions. Fraction blending with fuels could decrease the cold filter plugging point of final fuels, dramatically improving the commercial value of pyrolytic oil and effectively solving the waste oil disposal problem. [Display omitted] • Deoxygenation mechanisms investigated by experiments analysis and DFT calculation. • Pyrolysis technology reagard as an efficient pretreatment method for wast oil deoxygenation. • Pyrolytic oil was upgraded by SPAO-11-Pd/C can increase the iso-hydrocarbons content. [ABSTRACT FROM AUTHOR]

Soap stocks are by-products obtained during the refining process of vegetable oil, and are mainly feedstocks to produce acidified oil. In this work, an efficient process was developed to convert soap stock into a high-quality biofuel with low impurity content. A combination of acidification and catalytic cracking reactions employed as pretreatment was investigated to decrease the impurity content in the soap stock feedstock for obtaining a value-added biofuel. A high olefin content (approximately 47%) pyrolytic oil was obtained during the pretreatment. For further improvement of the cold flow properties, hydro-isomerization of pyrolytic oil for the formation of iso-alkanes over the Ce–Pt/SAPO-11and Ce–Pt/ZSM-5 catalysts was then carried out. The isomerization reaction temperature could be decreased to 320 °C because of the approximately 47% olefin content. The cold filter plugging point (CFPP) of the resulting product could be obtained at −11 °C, and the sulfur content could be decreased to lower than 10 ppm, which could meet the EN and ASTM specifications. [ABSTRACT FROM AUTHOR]

The increasing demand for transportation fuels, coupled with the depletion of petroleum resources and growing environmental concerns necessitates the development of efficient conversion technologies for the production of biofuels. Thermochemical approaches hold great promise for converting biomass into liquid fuels in one step using heat and catalysis. Several thermochemical processes are employed in the production of liquid biofuels depending on the target product properties: 1) direct thermal conversion; 2) catalytic cracking; 3) hydrodeoxygenation of plant oils and animal fats. Since enormous quantities of liquid fuels are consumed by transport vehicles, converting biomass into drop-in liquid fuels may reduce the dependence of the fuel market on petroleum-based fuel products. In this review, we summarize recent progress in technologies for large-scale direct thermochemical production of drop-in biofuels. We focus on the technical aspects critical to commercialization of the technologies for production of drop-in fuels from triglycerides, including cracking catalysts, catalytic cracking mechanisms, catalytic reactors, and biofuel properties. We also discuss future prospects for direct thermochemical conversion in biorefineries for the production of high grade biofuels. [ABSTRACT FROM AUTHOR]

Desulfurization and molecular structural modification are critical steps for producing high-quality biofuel. Here, we demonstrated an efficient and environmentally desulfurization process for converting waste cooking oil containing many impurities to low-sulfur biofuel, and this production process could be adopted on a large scale. This study found that composite catalysts (10 wt% base catalyst and 1 wt% cupric nitrate) could effectively remove the impurities (sulfur, chlorine and metal ions) in waste cooking oil during the deoxygenation process. The desulfurization rate was achieved at 94% over Cu(NO 3) 3 and K 2 CO 3 (1 wt%:10 wt%). The copper nitrate catalyst converted sulfur species into water and H 2 S. In addition, to further obtain high-quality biofuel with low cold flow property, the above generated biofuel with low sulfur content was hydro-isomerized over the Ce–Pt/SAPO-11 catalyst. Under the action of the bimetallic catalyst, the isomerization reaction could be carried out at low reaction temperature (300 °C) due to the high olefin content (approximately 43%) in pyrolytic oils. A high-quality biofuel production with low sulfur content (lower 10 ppm) and low cold filter plugging point (−20 °C) could be obtained through the above two processes, which all met the ASTM and EN specifications. Overall, a novel method was reported to convert low-quality waste cooking oil to high valuable biofuel. • The sulfides in waste cooking oil are removed via a facile method. • A novel process is developed to convert waste oil to high-quality biofuel, which satisfied the requirement ASTM D6751 and EN 14214. • This approach is a suitable technology for converting the waste oil with high amount of impurities, high viscosity, and waster content. • The removal of metal ions and chlorine-containing compounds in waste oil are studied. • The isomerization reaction temperature can be reduced to 300 °C. [ABSTRACT FROM AUTHOR]