Biofuels are fuels which are produced from organic matter by biological processes rather than geological processes. They are desired due to their properties of being renewable and a cleaner alternative to fossil fuels, as well as less expensive to produce. The demand for petroleum-based fuel has increased extensively due to the increasing industrialization and the growth in the transportation sector.
Scientists at the VIT University at Vellore, India, have found a way to extract such a biofuel from lemon fruits. K. Nanthagopal and fellow researchers, have managed to extract Lemon Essential Oil (LEO) from lemon rinds through the steam distillation process, and have successfully used it as biodiesel, partially substituting it with petroleum diesel.
Diagram of steam distillation method.
(Source: B. Ashok, K. Nanthagopal (2017). Lemon peel oil–A novel renewable alternative energy source for a diesel engine)
In order to meet the growing demands of fuel, biodiesels are prepared from readily available materials like fruits, vegetables, animal fats, etc. Biodiesels extracted from natural means are of great interest, due to their availability in numerous parts of the world and are more efficient, eco-friendly as well as more economical than fossil fuels. Some of the important properties of biodiesel extracts are similar to those of diesel fuels which makes them a suitable alternative to using in internal combustion engines.
In this current study, a biofuel LEO20 was prepared by blending 20% of lemon essential oil with 80% diesel. The LEO20 biodiesel was then used as fuel in a CI (compression-ignition) engine. Performance, combustion and emission analysis, of LEO20 blend, were compared with that of diesel fuel, and it was found that LEO20 performed as well as regular diesel. The emission values of the biofuel blend, were lower than diesel fuel, except for nitric oxides which were higher from the biofuel blend. Furthermore, the LEO20 can be used for the CI engine directly without undergoing any trans-esterification processes. Hence, the overall performance and emission characteristics of the lemon essential oil are better than the diesel fuel.
Lemon Essential Oil blend (20% LEO + 80% diesel)
(Source: B. Ashok, K. Nanthagopal (2017). Lemon peel oil–A novel renewable alternative energy source for diesel engine)
Due to the fact that chemical properties such as flash point and fire point of the lemon essential oil and diesel are nearly the same, handling and transportation of lemon essential oil is as easy as diesel fuel. Because the LEO lacks viscosity, it is easily atomized during the combustion process, and this is due to the lack of fatty acid compositions. Furthermore, it was earlier reported that, when a low viscous and low boiling point fuel (such as LEO) is blended with diesel, it accelerates the air-fuel mixing process which enhances evaporation process which results in more efficient and greener combustion.
Recent research on biofuels from peels of various fruits and vegetables have been the focus around the world to replace the conventional diesel fuel. Scientists have also extracted biofuels from the peels of orange fruits. They found similar results in terms of efficiency and regarding emissions it was found that carbon monoxide and hydrocarbon emissions were reduced significantly. In order to curb the nitric oxide emissions, diethyl ether has been added to blends of biofuels, with some success.
From these studies, it is evident that currently, biodiesels such as Lemon Essential Oil blends can partially substitute diesel fuel and power combustion engines. However, in the near future, these organic biofuels may be used without being incorporated in diesel, by themselves. Not only will this lead to reduced fuel expenditure, but also a cleaner environment with a major step towards reducing global warming.
References:
1] Ashok, B., Nanthagopal, K., Jathar, S., Sathyanand, T., & Logesh, S. (2017). Lemon Essential Oil–A Partial Substitute for Petroleum Diesel Fuel in Compression Ignition Engine. International Journal of Renewable Energy Research (IJRER), 7(2), 467-475.
2] Ashok, B., Raj, R. T. K., Nanthagopal, K., Krishnan, R., & Subbarao, R. (2017). Lemon peel oil–A novel renewable alternative energy source for diesel engine. Energy Conversion and Management, 139, 110-121.
