Hydrothermal catalysis of waste greases into green gasoline, jet, and diesel biofuels in continuous flow supercritical water

Abstract

The production of green gasoline, jet, and diesel biofuels from waste greases was achieved using a novel hydrothermal, continuous-flow catalytic process operating under supercritical water conditions, with recycled water the only added chemical. Thermally and chemically stable catalysts were explored to optimize yields of liquid biofuels and to minimize production of gases and acidic compounds. A 50:50 mixture of brown and yellow waste greases converted into 76.6 wt% liquid biocrude (BC); the remainder converted to water and gases. Less than 0.2% of the feedstock (FS) formed carbon char (mainly amongst catalyst particles). Various tubular reactors (Inconel, Hastelloy, titanium, stainless) showed no interior defects, erosion, or mass loss after runs. The titanium catalyst was fully recovered and regenerated back to its original potency. The BC was further refined into 28%, 48%, 20%, and 4 wt%, respectively for green gasoline, jet, diesel, and bunker. Biofuels were analyzed for compound class compositions and reaction mechanisms were proposed. Hundreds of identified fuel products (C 3 -C 35 ) from processing oleic acid as a pure model compound were identified. The neat green gasoline and diesel biofuels, along with a 50% green jet blend (with petroleum Jet A), were tested in appropriate spark ignition, turbine, and diesel engines at the University of Minnesota Engine Labs. The biofuels achieved 107.7%, 97.2%, and 101.3% engine power performance levels relative to petroleum fuels (91-Octane, Jet A, #2 Diesel) along with lower CO and pollutant emissions. The biofuels complied with American Society for Testing and Materials (ASTM) fuel specifications (D4814, D7566, D975) including mandated corrosion and low sulfur limits of all three biofuels.

Examples Showing the Utility of Doping Experiments in 1H NMR Analysis of Mixtures

“…We have been studying the pyrolytic conversion of various waste organic feedstocks comprising organic compounds into distillable biofuels. 7 The reactions are performed at high temperature in supercritical water (SCW) over a bed of solid catalyst. The reactor design is given schematically in the Supporting Information (SI).…”

“…The initial solution of butanoic acid (BA) "feedstock" was prepared by dissolving 5 g of BA in 100 mL of distilled water. Pure water was pumped (2 mL min −1 ) into the reactor 7 [10 cm L × 0.42 cm ID, packed with a titanium dioxide catalyst provided by the SarTec Corporation, 7 against a back-pressure regulator (BPR) set at 4000 psi] until the reactor had reached the targeted temperature of 600 °C. The homogeneous feedstock solution of BA was pumped into the reactor.…”

Progress in Corrosion Research on Alternative Liquid Fuels

“…A copper strip corrosion test showed that, despite the high acid value of the mixture, the corrosion properties were similar to those of diesel fuel [73]. Similarly, some researchers have studied the production pathway of green gasoline, jet, and diesel biofuels from waste greases and then proved that these new fuels blended with diesel pass the copper corrosion (D130) test and silver metal corrosion (D7681) test [74]. Diglycidyl ether ester derived from hempseed oil has also been tested for copper corrosion, and it was proved that its corrosion is low enough to be used as an alternative to diesel fuel [75].…”

Antibacterial Agents from Waste Grease: Arylation of Brown Grease Fatty Acids with Beechwood Creosote and Derivatization

“…Since aggregated trap grease carries various nutrients required for bacterial growth, its accumulation in landfills, sewers, and grease interceptors leads to further infestations by both micro- and macroorganisms, unpleasant odors, and larger municipal and environmental issues. Although aggregated trap grease is mainly considered a problematic municipal waste, its lipid components can be recovered as brown grease (BG) and converted to value-added products , such as extra durable composites, , renewable hydrogen, , hydrocarbons, , biofuels including sustainable aviation fuel, , biodiesel, ,,,− and biogas . The recycling and conversion of aggregated trap grease to valuable products can contribute to environmental remedies by reducing municipal pollution, lowering demands for crude oil, and providing economic benefits to both municipalities and waste management industries.…”