Currently, there is a worrying need to seek sustainable alternatives to replace fossil fuels, especially in the transportation sector, whose dependence on these non-renewable fuels is over 97% in the European Union. A team of researchers from the Polytechnic University of Madrid (UPM) and the University of Castilla-La Mancha (UCLM) has used waste from the fruit industry to extract orange oil and analyze its potential as a fuel for bioreactors.
The results obtained, published in Renewable Energy, demonstrate that orange peel oil is a viable alternative to be blended up to 15% with airplane fuel, without any significant inconvenience for their performance, and meeting all aviation standards requirements. The biofuel has been treated to reduce its tendency to form soot, so its use would help reduce the polluting emissions from current fuels.
The fruit industry, specifically the orange juice industry, generates a large amount of byproducts and waste, up to 30 million tons annually, which need to be managed to avoid serious economic and environmental problems. These waste products have a high content of terpenes, whose transformation allows for obtaining biofuels suitable to be mixed with conventional fuels, both in aviation and automotive. Among these wastes, orange peels contain orange oil, which can be extracted by pressing or using solvents.
Orange oil, mainly composed of D-limonene, could be used as a biofuel in aviation and automotive due to its excellent density and calorific power (together, indicating the amount of energy stored in the vehicle’s tank) and cold flow properties (i.e., the behavior of the biofuel at low temperatures).
However, the high tendency of orange oil to form soot during combustion requires its transformation through the chemical process of hydrogenation. David Donoso, a researcher at the UCLM School of Industrial Engineering, points out that “the main advantage of this process is that complete hydrogenation of the fuel allows for a 55% reduction in soot emissions, as we have verified in our study.”
The introduction of orange oil (and other citrus-derived terpenes) into a new market, such as transportation fuels, is of particular interest, as indicated by David Bolonio, a researcher at the UPM School of Mines and Energy, another member of the team who conducted the study.
Orange oil derived from the juice industry could replace 0.1% or 0.02% of the kerosene and diesel consumed in Spain in 2019, respectively. Clearly, the incorporation of orange oil into the biofuel market would not be enough to meet the goals of reducing polluting emissions to mitigate the effects of climate change, but it would help. “In the future energy scenario, multiple sources of biofuels will need to be employed to replace fossil fuels,” conclude the researchers. Rights: Creative Commons.
via: MiMub in Spanish
