Researchers produce new fuel from coal dust and algae

The technique can be used to produce both solid fuel and a high-quality crude oil(Credit: Shutterstock)

Researchers at the Nelson Mandela Metropolitan University (NMMU) in South Africa have developed a new fuel, known as Coalgae. Made from a combination of algae and coal dust, the latter of which is a waste product, the fuel could have a significant positive impact on the environment.

The NMMU researchers, led by Prof. Ben Zeelie, claim that the new product is a breakthrough in clean-burning fuel. The product uses coal dust as a major component, which is a waste product of the mining process. In fact, as much as 30 percent of coal is lost as dust during mining, and 50 to 60 million tonnes of the material are buried each and every year.

The practice doesn't only pose an environmental risk, with the waste releasing potentially harmful chemicals in the soil over long periods of time, but also represents a huge economic loss. Harnessing coal dust for fuel production eliminates both issues.

To produce the new fuel, the algae is grown in large artificial ponds, before being concentrated and mixed with the coal dust waste. Finally, it's formed into briquettes and dried.

Those briquettes can then be heated without oxygen at a temperature of around 450 °C (842 °F), burning without smoke to produce a solid, clean-burning fuel and a high-quality crude oil. The oil can be processed in existing refineries, while the solid product is suitable for use as thermal coal for generating heat and energy.

The researchers state that if the world's excess coal dust was used to help make Coalgae, then it could become widely used across the globe. In fact, they estimate that South Africa alone could produce enough to account for 40 percent of its own crude oil needs.

While the environmental benefit of Coalgae use could be huge, and the quality of the final product is high, it's unlikely to have a big impact on the cost of fuel.

"It is a very high-quality oil, like Texan sweet crude, rich in gasoline and aviation fuel components," said Professor Zeelie. "The price would be more or less the same, but the market would be stable, with significant environmental benefits."

The NMMU team is currently performing testing to confirm large-scale production costs. According to the researchers, organizations from countries across the globe – from the US to China – are already showing interest in the fuel.

Source: NMMU

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