Researchers from the Cardiff Cataylsis Institute have devised a way of increasing the yield of biodiesel by using waste left over from its production process.

Using catalysis, the Cardiff University researchers have been able to recycle an unwanted by-product created when biodiesel is formed from vegetable oil and convert it into an ingredient to produce even more biodiesel. It is believed the new process will have significant environmental benefits by improving the yield of biodiesel in a sustainable way that doesn’t require the use of additional fossil fuels, and could potentially reduce the costs of the biodiesel production process. The work could have international ramifications because, by 2020, the EU alone aims to have ten per cent of the transport fuel of every EU country come from renewable sources such as biofuels.

Fuel suppliers are also required to reduce the greenhouse gas intensity of the EU fuel mix by six per cent by 2020 in comparison to 2010. At present, biodiesel is produced by combining fats and oils with methanol, which is usually derived from fossil fuels. A waste product from this process is crude glycerol, which is formed on a large scale and contains many impurities that make it costly to purify and re-use in other areas. In their study, the researchers developed a way of turning the crude glycerol back into methanol, which could then be used as a starting reactant to create more biodiesel. To achieve this, they reacted glycerol with water, to provide the element hydrogen, and a magnesium oxide (MgO) catalyst. The reaction involved a simple one-step process and could be performed using mild conditions. Using the recycled methanol, the researchers estimate up to a ten per cent increase in biodiesel production, which they claim would be very helpful to industry. The work is currently in its early stages and in future studies the researchers will look to optimise the design of the catalyst and significantly increase its activity and selectivity.

Lead author of the study Professor Graham Hutchings, Director of the Cardiff Catalysis Institute, said: “Biodiesel manufacture is a growing part of the EU fuel pool, with statutory amounts being required to be added to diesel that is derived from fossil fuels. “We’ve provided unprecedented chemistry that highlights the potential to manufacture biodiesel in a much more environmentally friendly, and potentially cheaper, way, by converting an undesired by-product into a valuable chemical that can be reused in the process.” Co-author of the study Professor Stuart Taylor, Deputy Director of the Cardiff Catalysis Institute, said: “We set out to establish ways in which the waste product glycerol could be used to form other useful compounds, but we were surprised when we found that feeding glycerol and water over such a simple catalyst gave such valuable products and interesting chemistry. “This research has the potential to transform the way in which waste is dealt with, and seriously improve the quality of life by reducing carbon emissions from fossil fuels and encourage efficient use of resources.”