Team makes sustainable aviation fuel additive from recycled polystyrene

A brand new examine overcomes a key problem to switching business plane within the U.S. from their near-total reliance on fossil fuels to extra sustainable aviation fuels. The examine particulars a cheap methodology for producing ethylbenzene—an additive that improves the useful traits of sustainable aviation fuels—from polystyrene, a tough plastic utilized in many client items.

The examine has been published within the journal ACS Sustainable Chemistry & Engineering.

Fuels derived from waste fats, oil, grease, plant biomass or different nonpetroleum sources lack adequate ranges of fragrant hydrocarbons, which assist hold gas techniques operational by lubricating mechanical components and swelling the seals that shield from leaks throughout regular operations, mentioned Hong Lu, a analysis scientist on the Illinois Sustainable Know-how Middle who led the brand new analysis. ISTC is a division of the Prairie Analysis Institute on the College of Illinois Urbana-Champaign.

Whereas ethylbenzene is an fragrant hydrocarbon and may be derived from fossil fuels, discovering a sustainable strategy to produce it could support the aviation business’s conversion to sustainable jet fuels.

The U.S. Division of Power, the U.S. Division of Transportation, the U.S. Division of Agriculture and different authorities companies created a roadmap for addressing the climate-related impacts of fossil-fuel-derived aviation fuels. The Sustainable Aviation Gasoline Grand Problem units bold objectives for the manufacturing of home sustainable aviation fuels to three billion gallons per 12 months by 2030, and 100% of projected aviation jet gas use, or 35 billion gallons per 12 months, by 2050.

Current requirements require a minimal of 8.4% fragrant hydrocarbons be included in any mix of sustainable aviation fuels and fossil-derived fuels “to maintain compatibility with existing aircraft and related infrastructure,” the researchers report. Whereas this rule will increase the protection and efficacy of the general gas combine, it severely limits the usage of sustainable fuels, which presently include solely about 0.5% fragrant hydrocarbons, Lu mentioned.

“Currently, they use a blend of 20% to 30% sustainable aviation fuels and 70% to 80% conventional jet fuel,” he mentioned. This lag in conversion to sustainable fuels stems from a number of elements, one among which is the necessity for sufficient aromatic hydrocarbons within the combine. Different necessary elements contain qualities just like the mix’s volatility, acidity, moisture content material and freeze level.

Lu and his colleagues selected to develop ethylbenzene as a result of it has a decrease tendency to kind soot upon burning than different extremely fragrant compounds. And so they selected to begin with polystyrene as a result of it’s wealthy in hydrocarbons and is abundantly out there within the waste stream.

“We produce in the U.S. about 2.5 million metric tons of polystyrene every year, and almost all of it is disposed of in landfills,” Lu mentioned.

To transform the polystyrene to ethylbenzene, the staff used thermal pyrolysis, heating it to interrupt the polymer down right into a styrene-rich liquid. A second step, hydrogenation, transformed it right into a crude ethylbenzene, and distillation yielded a product that was 90% pure.

When blended with a sustainable aviation gas, the polystyrene-derived ethylbenzene carried out “virtually in addition to ethylbenzene derived from fossil fuels,” Lu mentioned. Additional purification would enhance its efficiency.

“We did a preliminary cost analysis, and we found that the ethylbenzene produced from waste polystyrene is cheaper than that produced from crude oil. And a lifecycle analysis of our ethylbenzene found it reduced carbon emissions by 50% to 60% compared with the ethylbenzene made from crude oil.”

Lu and his colleagues hope to additional develop this additive to assist increase the usage of sustainable fuels in aviation.