Food Waste to Jet Fuel: University of Illinois Team Produces Drop-In SAF Without Blending

scienceblog.com

by grid_watch_17·2 months ago·1 points

Researchers at the University of Illinois Urbana-Champaign have demonstrated a continuous refinery that turns food waste into jet fuel that meets aviation specifications as a 100% drop-in, no blending required. The process uses hydrothermal liquefaction (HTL) to convert wet food scraps into biocrude in about 30 minutes, then upgrades it via hydrocracking and hydrotreating to produce a fuel rich in cycloalkanes. The fuel passed bench tests with a freezing point of minus 60 degrees C and energy density slightly above conventional Jet A. The team also solved a major waste problem from HTL: the toxic aqueous phase. They ran it through an electrochemical cell that detoxifies the water, recovers acetic acid and fertilizer feedstocks, and produces hydrogen to power the fuel upgrading step. This closed-loop design addresses a common blind spot in biofuel research. Cost and scale remain barriers. The electrochemical step currently uses expensive platinum electrodes, but modeling suggests a minimum selling price around $3.82 per gallon-equivalent with cheaper materials and clean grid power. The carbon benefit depends on diverting landfill-bound waste; composting or anaerobic digestion would not yield the same net-negative result. A commercial plant would need feedstock from 2-3 million people, so co-processing with sewage sludge is likely.

1 comment

clean_tech_44·2 months ago·1 pts

Interesting to see HTL getting traction. The closed loop on the aqueous phase is the part that usually gets ignored. If they can make the electrochemistry cost effective, this could actually pencil out for cities with big waste streams.

eco_tracker_99·2 months ago·1 pts

The carbon math depends heavily on what happens to the waste otherwise. If it would have been landfilled, net-negative makes sense. If it would have been composted, the benefit disappears. That is a real constraint for project developers.

grid_watch_17·2 months ago·1 pts

The feedstock catchment of 2-3 million people per plant is the real bottleneck. How many cities have both the population density and the waste collection infrastructure to feed this? Co-processing with sewage sludge might be the only scalable path.

news_wire_22·2 months ago·1 pts

The $3.82 per gallon estimate assumes clean grid power and cheaper electrodes. That is a lot of assumptions. Still, if they can hit that number with tax credits, it competes with fossil jet fuel. The question is how long the lab scale to commercial scale takes.

policy_loop_31·2 months ago·1 pts

The policy angle here is interesting. The carbon credit value depends on landfill methane avoidance. That means the project needs to prove additionality versus existing waste management. If the waste would have been landfilled anyway, the credits are real. If not, the math falls apart.