Science and technology


South Africa demonstrates algae-to-energy technology

30 January 2014

Innovative technology that uses algae to convert waste coal dust into a clean, high-quality coal which can readily be processed into biofuel was publicly demonstrated at the Nelson Mandela Metropolitan University in Port Elizabeth on Monday.

The pioneering technology has been developed by the university over the past three years with funding from the Department of Science and Technology, and plans are afoot for its products to be commercialised, the university said in a statement ahead of Monday's showcasing event.

One of the main areas of research at university's institute of chemical technology, InnoVenton, has been the conversion of waste coal into a usable, high-quality clean coal using algal biomass. The institute's researchers have found that the microalgae can be combined with coal and charcoal and acts as an excellent binder for fine coal.

"If you mix coal dust and algae biomass, the algae adsorps [collects] onto the surface of the coal and binds the dust together," InnoVenton's Professor Ben Zeelie said. The result is a coal-algae composite [briquette or pellet], for which they've coined - and trademarked - the name "Coalgae".

"The Coalgae composites may be used as a substitute in applications that require coal, or may be further processed through a variety of additional technologies, such as pyrolysis (heating in the absence of oxygen)," the institute said. "The result of the additional processing is a bio-fossil crude oil blend that may be processed into a variety of fuels, including gasoline, diesel, kerosene, aviation fuel, and heavy fuel oil.

"Carbon sequestration, the upgrading of low grade coal and the production of clean water (a spin-off of the process) are among the advantages of the production of Coalgae, which, along with the production of the bio-crude oil, have presented commercial opportunities."

According to the institute, consulting engineering firm Hatch-Goba recently completed a pre-feasibility engineering study on the microalgae technologies, resulting in a "robust and cost-effective" design for Coalgae production on a semi- and full commercial scale. A full feasibility study will be conducted in the first half of this year.

The institute demonstrated various aspects of Coalgae technology on Monday, include the cultivation of microalgae in a closed photo-bioreactor system developed by the university, the use of coal-generated flue gas to meet the microalgae's need for carbon dioxide and fixed nitrogen, the harvesting of the microalgae, the production of the coal-microalgae composites, and their conversion into raw bio-crude oil.

Speaking at the event, the Department of Science and Technology's deputy director-general for research, development and innovation, Mmboneni Muofhe, said the technology would help to separate South Africa's biofuels sector from its food-producing sector, and bring the realisation of a full-fledged biofuels industry in the country one step closer.

South African fuel producers will begin mandatory blending of petrol and diesel with biofuels from 1 October 2015 as the country moves to encourage investment in its biofuels sector and reduce its reliance on imported fuel.

"By 2015, the government intends all transport fuels to be a blend, with biofuels making up at least two percent of the blend. Coalgae exceeds this target," the department said in a statement last week.

And there's certainly no shortage of raw material at hand. Millions of tons of coal dust go to waste every year in South Africa and elsewhere. According the department, the country currently has over 1-billion tonnes of discarded coal or coal "fines" (fine coal particles), which constitute a serious environmental nuisance.

In addition, Coalgae can be delivered using existing petroleum or petrochemical infrastructure.

"The ability to combine the two feedstocks (coal fines and algae) means that only one process is necessary, instead of two," the department said. "Another advantage is that the technology will reduce the logistical challenges of accessing blended biofuels, as well as the capital investments required for the blending and distribution infrastructure."

SAinfo reporter and Nelson Mandela Metropolitan University

South Africa demonstrates algae-to-energy technology InnoVenton director Ben Zeelie (right) explains the process of creating Coalgae to Nelson Mandela Metropolitan University rector Derrick Swartz (left), while Department of Science and Technology deputy director-general Mmboneni Muofhe (second from right) looks on (Photo: Nelson Mandela Metropolitan University)

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