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Scrubbing process converts carbon dioxide into fuel

GEA Niro suggests this could help industries with a large CO2 footprint to become more environmental friendly and reduce operational costs, especially cost penalties from the discharge of greenhouse gases. This includes the EU's CO2 quota directive which aims to lower the cap on CO2 emissions by 60 per cent between 2013 to 2020.

The new process works by feeding the gas to algae and transforming the algae to alcohol by fermentation and the residual bio matter to fertilizer. The exhausted yeast cells are then spray dried into protein powder for animal feed.   

First of all, the CO2 is scrubbed from processes with high CO2 concentrations such as rotary ovens of cement plants. The CO2 is then introduced to basins that contain large volumes of algae which consume the gas. As algaes are polysaccharides containing fermentable sugars, these are easily converted to alcohol through fermentation. The alcohol can then be recovered for use as fuel, leaving the remaining algae biomass and yeast cream for drying into useful fertilizer and animal feed respectively.

GEA Niro suggests that the payback period for this installation is as yet uncertain, with the return on investment determined mainly by the tax rates and other penalties governments impose on CO2 emissions.  “The payback time on a process like this depends largely on how much the plant is paying in emissions taxes and to a lesser extent on the sales price of the produced fertilizer, alcohol and protein for animal feed,” said Robert Djernaes, food sales group manager of GEA Niro. “Ultimately though, reducing the cost for the plant will reduce the cost for the client and therefore the product’s consumer.”

Moreover, while the principle is simple, the process implementation is difficult due to the very large installations and large mass flows involved. GEA says that it does however, have the necessary core competence and correct organisation to handle projects of this magnitude.

The process is currently in the experimental stage, with extended tests running in Spain for growing algae in connection with a cement plant. Preliminary analysis suggests that it is a successful process for reducing CO2 emissions.