10 mai 2011 | EN
Adding nanoparticles improves biofuels, say researchers
[CHENNAI] Adding 'nanoparticles' improves the ignition of biofuels and makes them emit less toxic fumes, Indian researchers report.
The findings that adding alumina nanoparticles helps biofuels and conventional fuels release fewer toxic emissions and smoke when burned in internal combustion engines were published by Ramachandran Bhagavathiammal Anand, associate professor of mechanical engineering at the National Institute of Technology (NITT), Tiruchirapalli, and researcher Jaffar Sadhik Basha, last month (4 April) in the Journal Of Renewable And Sustainable Energy.
Indian scientists are working on biodiesels from non-edible oilseeds such as Jatropha; Azadirachta indica or 'neem'; and Madhuca longifolia or ‘mahua’ as potential sources of biofeul.
But, "the main problems associated with the diesel engines are the emissions of harmful pollutants such as nitrogen oxides and smoke. To reduce both nitrogen oxides and smoke simultaneously, water is incorporated with the diesel or biodiesel", Basha told SciDev.Net.
The researchers prepared a biodiesel emulsion fuel by mixing 83 per cent of Jatropha biodiesel; 15 per cent of water; and two per cent of 'surfactants' or surface-active substances such as detergents, foaming and wetting agents; in a mechanical agitator.
The technique helped reduce smoke emission but there were still some critical problems associated with the water-diesel emulsion fuel and water-biodiesel emulsion fuels. "Ignition delay was prolonged on adding water to the fuels (both diesel and biodiesel) which, in turn, led to inferior combustion in the diesel engine," Basha explained.
In general diesel and biodiesel are less volatile, which not only delays ignition during combustion, but also leads to incomplete burning, Basha said.
"To improve the emulsion fuel properties, nanoadditives (including those derived from alumina and carbon) are added for better combustion in the diesel engine," Anand said.
Alumina nanoparticles are cheap, enhance burning and can be made in chemical research laborator[ies], Anand said. "We, therefore, used alumina nanoparticles to improve the diesel/biodiesel emulsion fuel properties."
The researchers said that the effect of alumina nanoadditives on biodiesel emulsion fuels with a higher proportion of water is yet to be investigated for performance and emissions in diesel engines.
"Biofuels like Jatropha, Pongamia, castor, and 'mahua' can serve as a propitious alternative fuel in diesel engines," said Anand. "A developing country like India should lay importance on biofuels and reduce the crude oil dependence on the oil-rich countries."
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