Dr Noel Simento:
"In the processes that you use for capture there are many processes. Most often you will hear about three main processes for carbon dioxide capture when related to power generation. You’ll hear of oxy-fuel, you’ll hear of integrated gasification combined cycle processes and you’ll hear of post combustion capture processes. So I’ll explain each one of them. Oxy-fuel combustion is where you take air and you separate the nitrogen from the oxygen early and then you use the oxygen to combust coal and the result is you then get a pure stream of carbon dioxide. I shouldn’t say pure, it’s a flue gas of carbon dioxide which has some of the contaminants of coal. You then have to take the gas and treat it before you send the CO2 away for storage, that’s the oxy-fuel process. The integrated gasification combined cycle process, often it’s called IGCC for short, that’s a different process, once again you separate the oxygen from the nitrogen in air early, you use the oxygen but you don't burn the coal completely, you burn it to an intermediate product, called carbon monoxide. You use the carbon monoxide then to generate your electricity, you also produce hydrogen in that process and you can use that too for energy production. But what it gives you then is once again a purer stream of carbon dioxide that you can take away for storage. The post combustion capture process is a little bit different, this is where you don't separate the oxygen and nitrogen in air, you use air as it is and you combust the coal and you generate electricity, but the flue gas that you produce when you do that, contains a lot of nitrogen and carbon dioxide and the various contaminants. You now have to treat that volume of gas and clean it up before you send the carbon dioxide for storage, it’s a much larger volume of gas because in the post combustion capture process you haven’t separated the nitrogen from the oxygen early. So those are the three main capture processes that people are working on currently to generate power in low emissions technologies."
Categories: Australia Energy Issues
Author: Dr Ziggy Switkowski