Researchers from France have explored a promising method to convert used frying oils into valuable energy sources, addressing both renewable energy production and waste management. The study, led by scientists affiliated with the University of Lyon and the Ecogras Company, was published in the Journal of Analytical and Applied Pyrolysis.
The research focuses on the pyrolysis of used frying oils, a process that involves heating the oils to high temperatures in the absence of oxygen to break them down into simpler molecules. France generates around 100,000 tons of waste edible oils annually, which must be collected and transformed by specific companies. The researchers aimed to convert this waste into energy sources such as hydrogen for fuel cells, hydrogen and carbon monoxide mixtures for biodiesel production, or high-value hydrocarbon mixtures.
The team built a laboratory pilot plant to study the pyrolysis process using a crude used frying oil called VEGETAMIXOIL. They investigated the effects of temperature (ranging from 700 to 800 degrees Celsius), residence time, and the addition of various substances like reaction initiators (hydrogen peroxide), inhibitors (thiophene), and diluents (water or nitrogen). The results showed that the optimal conditions for pyrolysis were at 800 degrees Celsius with water as the diluent. This setup produced dihydrogen (hydrogen gas) at a 40% yield, along with hydrocarbons ranging from methane to propylene. Carbon monoxide and carbon dioxide were also produced but in lower amounts.
One of the significant findings was that the hydrogen to carbon monoxide ratio obtained under these conditions is favorable for low-temperature Fischer-Tropsch reactions, a process used to convert gases into liquid hydrocarbons, which can be used as biodiesel. This research highlights the potential for converting waste frying oils into valuable energy sources, contributing to both renewable energy production and waste management solutions. The practical applications for the energy sector include the production of clean hydrogen for fuel cells and the synthesis of biodiesel, which can reduce dependence on fossil fuels and promote a more sustainable energy future.
Source: Journal of Analytical and Applied Pyrolysis
This article is based on research available at arXiv.