NELSON Mandela Metropolitan University’s innovative algae-to-energy project has taken a major step forward with the arrival of a custom- made algae biomass liquefaction reactor – the only one of its kind in the world – which is successfully converting algae biomass into a bio- oil, not unlike crude oil, and other useful products.
The project, the brainchild of the university’s internationally recognised institute of chemical technology, InnoVenton, uses micro-algae to convert harmful carbon dioxide from the atmosphere into oil, hydrogen gas and a water solution rich in sugars and proteins.
Officially launched in February, the cutting edge “green” technology will be rolled out to industry later this year and could ultimately play a major role in providing a new route to sustainable renewable energy generation. A t the same time it could minimise the environmental harm caused by carbon dioxide emissions from power plants and factories
InnoVenton’s Prof Ben Zeelie said the new liquefaction reactor, designed and custom-made in collaboration with the University of Cape Town’s chemical engineering department, pumps algae biomass at a high temperature and pressure into the reactor system, and converts it into oil (at about 60% of the biomass) . “What’s happening here is what happens under the earth’s crust over many millions of years. We are just speeding up the process.”
The oil could be converted into petrol, diesel, plastics, and many other chemical products. “One sits and dreams about projects such as this — it’s very exciting when you get to see them starting to work.”
The photo-bioreactor — the system whereby the algae is grown — is housed in a huge greenhouse on the Port Elizabeth campus. Carbon dioxide is pumped through a solution of algae that is grown in salt water and housed in custom-made plastic tubes to allow sunlight in for photosynthesis. The resulting biomass is “harvested” by a settling process at which point it resembles very finely chopped spinach.
“We’ve already been able to demonstrate that we can successfully grow the algae under widely ranging environmental conditions and at higher growth rates than initially targeted, even at extremely high summer temperatures. The next step is to set up a one hectare photo-bioreactor facility as a technical demonstration facility at a local Port Elizabeth company (not yet named), that produces about 120000 tons of carbon dioxide a year.”
InnoVenton has established a private company, Zalgen (South African Algae Energy Company), which will ultimately commercialise the technology.
Zeelie said the project was giving rise to other “green” projects, but declined to give specific details until the university had obtained patent protection for some . ” Using a combined algae cultivation and biomass liquefaction facility to provide both electricity and fresh water to rural communities at a very low cost is but one example being explored.”
Zeelie said the main aim of the project was the captur e and storage of solar energy in a sustainable manner. “For every kilogram of algae biomass produced, about two kilograms of carbon dioxide have been taken out of the air.”
Some very demanding challenges still need to be overcome. “For example, the reliance on commercial fertilisers for the cultivation of micro-algae, as practised internationally, may not be sustainable.”
But “InnoVenton has devised a concept whereby most of the nutrients will be recovered and recycled, thereby reducing the dependence on such fertilisers. If InnoVenton can successfully demonstrate this concept, it will dramatically change the way in which the world will view algae cultivation.”
Zeelie said the primary product of the micro-algae was stored solar energy, in the form of a bio-oil. “Obviously there are numerous other products and even business opportunities arising from this project, including food supplements, feed products for fish and animals and high- value chemicals like bactericides.
“These are, however, secondary objectives, as the sustainable production of bio-oil is the primary objective at present.”
Zeelie said the project, in partnership with industry countrywide, aimed to produce 400000 tons of algae biomass per year. It will be rolled out to industry in the second half of this year.