by Mike Timko (Worcester Polytechnic Institute/Biofuels Digest) A recent study led by a team from Worcester Polytechnic Institute shows that metal-oxide-based catalysts reduce char build up during biofuel conversion processes, increasing bio-crude oil yield and decreasing yields of low-value byproducts. … Utilizing wet food waste requires a fast and efficient conversion technology. Hydrothermal liquefaction (HTL), which is being studied by the WPI team, is a thermochemical process that rapidly decomposes organic wastes with the aid of high-temperature pressurized water (~374 °C and ~22 MPa) into energy-rich, crude-oil-like product, or bio-crude oil. Unlike many other technologies, HTL does not require a dry feed, making it especially suitable for wet feeds, including food waste, sewage sludge, and other wet wastes. The major technical challenge facing HTL is directing carbon to the bio-crude oil, rather than the less valuable byproducts that accumulate in solid char, aqueous, and gas phases. Catalysts offer an opportunity to direct carbon toward the bio-crude oil; however, char accumulation on solid surfaces can rapidly deactivate otherwise promising catalysts.