Coconut SAF as an alternative to jet fuel
Coconut oil is processed into SAF, which is chemically similar to the commonly used jet fuel JET A-1.
Photo Credit: Osaka Metropolitan University
Scientific Frontline: Extended "At a Glance" Summary: Coconut Oil-Based Aviation Biofuel
The Core Concept: A novel aviation biofuel synthesized from discarded coconuts using a co-solvent method, which can be blended with conventional jet fuel (Jet A-1) without compromising engine performance.
Key Distinction/Mechanism: Unlike traditional jet fuels, this biofuel is produced under ambient temperature and pressure using a co-solvent method combining coconut oil extracts with acetone and alcohol, resulting in two potential biofuels (FAME and FAEE) that reduce hydrocarbon emissions.
Major Frameworks/Components:
- Co-solvent Method: Utilizes acetone and alcohol (methanol or ethanol) to process coconut oil extracts into biofuel under ambient conditions, conserving energy and maintaining purity.
- Biofuel Variants: Production of Fatty Acid Methyl Esters (FAME) using methanol and Fatty Acid Ethyl Esters (FAEE) using ethanol.
- Performance Metrics: Experimental data showing comparable thermal efficiency to Jet A-1, with reduced hydrocarbon emissions and no significant increase in CO₂ or NO emissions.
Branch of Science: Bioengineering, Chemical Engineering, Thermodynamics, Environmental Science.
Future Application: Advancing toward 100% biofuel engine operation, improving long-term storage stability and material compatibility, and utilizing the 30% of harvested coconuts currently discarded in Southeast Asia to mitigate regional fuel shocks.
Why It Matters: Provides a sustainable, eco-friendly alternative to conventional jet fuels, offering a pathway to reduce the aviation industry's environmental footprint by lowering hydrocarbon emissions without requiring major modifications to existing gas turbine engines.
With airlines and consumers increasingly concerned about carbon, nitrogen, and hydrocarbon emissions, biofuels have emerged as a green alternative. Among these, biofuels made from coconut oils are particularly attractive because they possess fatty acid chain lengths similar to the hydrocarbon chain lengths required for jet fuel, suggesting they could serve as effective fuels with minimal processing.
Using a unique cosolvent method, a team from Osaka Metropolitan University has created a coconut oil–based fuel that can be added to jet fuel without lowering performance.
The cosolvent method combines coconut oil extracts with acetone and alcohol. This process allows the fuel to be produced at ambient temperature and pressure, reducing energy consumption and ensuring purity during manufacturing. The researchers created two biofuels that could potentially be added to conventional jet fuel: FAME, using methanol, and FAEE, using ethanol.
To determine the optimal blend, the team varied the ratios of FAME and FAEE mixed with Jet A-1, a conventional jet fuel. The researchers sought to find the ideal ratio that balanced fuel consumption, thermal efficiency, and exhaust gas emissions using a small turbojet engine.
They found that despite increases in fuel consumption as the biofuel blending ratio increased—likely due to differences in the heating values of the two fuels—the thermal efficiency remained comparable to that of Jet A-1.
Their trials also demonstrated a decrease in hydrocarbon emissions, as well as no significant changes in CO₂ or NO emissions, two pollutants largely responsible for the carbon and nitrogen footprints of airlines.
“The experiments showed that our fuel blend can operate in existing gas turbine engines without major loss of efficiency or engine performance, and without increasing emissions,” summarized Dr. Huynh Phuong Uyen Nguyen of the Graduate School of Sustainable System Sciences.
These findings could be especially important for Asian countries. In Southeast Asia, approximately 30% of harvested coconuts are discarded because they do not meet commercial standards. This waste creates a potential source for biofuel production, particularly because the region is at risk of fuel shock.
“In the future, we want to improve fuel consumption performance and establish technologies for operating engines on 100% biofuel,” Dr. Ogawa said. “Looking ahead, we also want to advance the practical application of this fuel by improving its long-term storage stability, material compatibility, and environmental impacts through life-cycle assessment.”
Funding: This work was supported by an Osaka City Innovation Support Grant.
Published in journal: Fuel
Authors: Shinichiro Ogawa, Takuto Hongo, Yasuaki Maeda, Huynh Phuong Uyen Nguyen, and Koichi Mori
Source/Credit: Osaka Metropolitan University
Edited by: Scientific Frontline
Reference Number: beng082026_01
