Melanie Williams Consulting

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Putting in the energy to recycle carbon dioxide

It’s holiday time. Exactly twenty-seven years ago, colleagues and I filed a patent , covering the production of formic acid from carbon dioxide and hydrogen. Formic acid is principally used as a preservative and antibacterial agent in livestock feed. High pressure and heat were required to make it work, not surprisingly, as carbon dioxide is a very stable molecule. In those post oil shock days the focus was on making chemicals from other sources of carbon. Saving carbon was not our aim. 

Companies are now turning to carbon dioxide chemistry as a way of  ‘capturing’ or ‘recycling’ carbon to save greenhouse gas emissions and prevent the planet overheating. Have recent announcements revealed real progress in recycling carbon dioxide?

A few months ago IKEA and Newlight announced that IKEA would produce AirCarbon under technology license to help move away from virgin fossil-based plastics. AirCarbon is a type of plastic made from ‘carbon emissions’, which sounds like carbon dioxide, but on closer inspection it turns out that the emissions they are targeting are methane (biogas) from landfill sites.  Methane from landfill sites is normally collected anyway and turned into electricity. Carbon dioxide will be a ‘future’ target. 

What about LanzaTech, who announced a new project in 2015 to use microbes to capture carbon in steel mill waste gases to make ethanol?   Well, steel offgas is mainly carbon monoxide, which is quite different from carbon dioxide and can be transformed into chemicals using existing processes. LanzaTech may have more efficient chemistry but it is not the answer to the carbon dioxide question. 

Then there is Carbon Recycling International, which makes methanol from carbon dioxide and hydrogen (from water). They do confirm that energy needs to be put into the process, and at their plant in Iceland, it is from renewable sources. The plant uses renewable electricity to make hydrogen, which is converted into methanol in a catalytic reaction with carbon dioxide. The carbon savings have been certified.

Other researchers are using carbon dioxide by keeping all or most of the molecule intact which could be successful, if niche e.g. to make carbonates.  But, as a large-scale replacement for fossil fuel derived chemicals and plastics, carbon dioxide will only save greenhouse gas emissions if renewable energy is used as an energy source. 

Published: 16 August 16

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