Prawn power to help drive cheaper, greener biofuel production

Prawn shells could help make the production of biodiesel faster, cheaper and more environmentally-friendly, according to research by scientists in China.

The shells have been tested for use as a catalyst in the production of biofuel, taking the place of strong bases or acids that are normally used to convert soybean, rapeseed and other plant oils into diesel fuel.

Under conventional biofuel refinery processes, neutralising the catalyst used to accelerate the breakdown of organic material requires a large volume of water, which results in polluted wastewater that then has to be treated and disposed of. Moreover, the catalyst cannot be reused, increasing the costs associated with the enzymes and acids that are typically used.

Howeverm, researchers at Huazhong Agriculture University in Wuhan claim to have developed an alternative approach based on a mixture of prawn shells that have been heated until they become porous and potassium fluoride.

The resulting material turned rapeseed oil into biodiesel faster and more efficiently than some conventional catalysts, with tests converting 89 per cent of the oil in three hours.

The prawn-shell catalyst can be reused and its use in biodisel production would minimise waste production and pollution, the scientists noted in their report, which is to be published in the August 20 issue of Energy & Fuels journal.

The shells are "an excellent raw material for the preparation of catalyst, due to its wide source, low price, favorable biodegradability and environment-friendly property", the study authors wrote.

However, the practice of intensive prawn farming has been frowned upon by green groups who say it has led to the degradation of mangroves in Asia, where 75 per cent of farmed shrimp is produced.