Researchers at Osaka Metropolitan University in Japan have developed an aviation-compatible fuel from coconut oil and tested it in a micro jet engine, demonstrating its potential as an alternative aviation fuel, avi-go.com reported.
The research team described the work as the first experimental effort to produce biofuel from coconuts and test its performance in a jet engine.
The researchers used a co-solvent method to process waste coconut fruit discarded during commercial oil extraction. The material was combined with 10% acetone and an alcohol before being processed at room temperature and subsequently at temperatures below the boiling point. The approach differs from conventional sustainable aviation fuel production methods that require high pressures and intensive heating.
The process also allows glycerin and biodiesel to be recovered as byproducts, while the acetone and alcohol used in processing can be recovered and reused.
For engine testing, the researchers blended the coconut-based biofuel with kerosene at different proportions, ranging from 10% biofuel and 90% kerosene to an equal 50:50 mixture.
The tests showed that the blends achieved thermal efficiency comparable to that of pure kerosene. However, fuel consumption was slightly higher, which the researchers attributed to coconut oil’s lower ignition temperature.
Carbon dioxide and nitric oxide emissions remained consistent with those from kerosene across all blending ratios. Meanwhile, emissions of unburned hydrocarbons, also known as volatile organic compounds, declined by 5% to 40%, depending on the proportion of coconut-based fuel in the blend. These pollutants are released in greater quantities when aircraft engines are idling or operating during taxiing.
The researchers said further studies are required before the fuel can be commercialised. One key concern is the increase in carbon monoxide emissions observed when the coconut-based biofuel was blended with jet fuel, as the emissions could pose health risks to ground personnel.
