Cardiff University researchers improve biodiesel yields

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

Using simple catalysis, the researchers have been able to recycle an undesired by-product of the vegetable-oil-to-biodiesel conversion process, and convert this residue into an ingredient to produce even more biodiesel.

It is believed this 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 results were published in the journal Nature Chemistry.

‘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,’ says the study’s lead author Professor Graham Hutchings, director of the Cardiff Catalysis Institute (CCI).

By 2020, the EU aims to have 10% 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 6% 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 from the CCI 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, the researchers 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.

‘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,’ says Professor Stuart Taylor, deputy director of the CCI and the study’s co-author.

Using the recycled methanol, the researchers estimate up to a 10% increase in biodiesel production, which they claim would be very helpful to the industry at this point in time.

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.