Researchers developed a cost-effective method to produce ethylbenzene, a key additive for sustainable aviation fuels, from waste polystyrene. This innovation addresses a major challenge in transitioning commercial aircraft from fossil fuels to sustainable aviation fuels.
Why Polystyrene?
Polystyrene, a widely used plastic in consumer products, often ends up in landfills. The U.S. generates approximately 2.5 million metric tons of polystyrene waste annually. Researchers saw an opportunity to repurpose this waste due to its high hydrocarbon content.
The Process
The team developed a two-step method to convert polystyrene into ethylbenzene:
- Thermal Pyrolysis: Heating polystyrene to break it down into a styrene-rich liquid.
- Hydrogenation: Converting the liquid into crude ethylbenzene, followed by distillation to achieve 90% purity.
This process yields an ethylbenzene product that performs almost as well as its fossil fuel-derived counterpart. Further purification could enhance its efficacy.
Significance of SAFs:
- SAFs are critical for achieving net-zero CO2 emissions in aviation.
- Current aviation fuel standards (e.g., Jet A) restrict the blending of nonpetroleum-based fuels like synthetic paraffinic kerosene (SPK) to 50 vol%.
- The restriction is partly due to SPK’s limited seal-swelling ability, which is essential for fuel system integrity.
Environmental and Economic Benefits
- Carbon Emissions Reduction
- The lifecycle analysis of the polystyrene-derived ethylbenzene shows a 50% to 60% reduction in carbon emissions compared to ethylbenzene made from crude oil.
- Cost-Effectiveness
- The production cost of ethylbenzene from waste polystyrene is lower than that of crude oil-based ethylbenzene, making it a financially viable alternative for the aviation industry.
Reference: ACS Pub, SciTech Daily
