Researchers from the Gas Engineering Department at the Petroleum University of Technology, in Ahwaz, Iran, have created a high-speed conversion method capable of turning waste cooking oil into fuel, using caustic soda and ultrasound. Biodiesel signifies a fuel that is likely to be cleaner and more sustainable than crude oil-based fuels.
The research findings have been published in the International Journal of Oil, Gas and Coal Technology.
The research team, consisting of Ehsan Khosravi, Ahmad Shariati and Mohammad Reza Khosravi Nikou, explained that the environmental and economic issues relating to petroleum-based fuels have resulted in an increased demand for other options.
Several countries have already started to adopt biodiesel, especially to operate the country’s public transport. Crops grown for the purpose of fuel production, and biomass procured from plant wastes are two sources. However the recycling of waste cooking oil, either vegetable oils or animal fats, is considered a potentially sustainable feedstock.
The Iranian team have demonstrated that it is possible for biodiesel to be made from cooking oil. It can be achieved using direct ultrasonic irradiation with sodium hydroxide (NaOH), caustic soda, or potassium hydroxide (KOH) as chemical catalysts for a method known as transesterification reaction. The team explains that when methanol was added to the waste oil before conversion, the conversion efficiency went up to 99%.
When methanol was added, it decreased the reaction time to just 10 seconds. It is possible to have a complete conversion with just 0.75% NaOH or 1.25% KOH, if the pellets are pulverized and mixed fully with the methanol raw materials and waste oil.