Hacker News Reader

coal isn't burned with fire, but instead chemically combusted

I'd like some clarification on the difference between "fire" and "chemical combustion"

One definition of "fire" demands "oxygen from the air":

https://www.google.com/search?q=define+fire&oq=define+fi...

The fuel here doesn't react with air, but with a solid oxidiser (Fe2O3). It's a solid-solid reaction, whose products are gases (CO2 and H2O). Just like a solid-fuel rocket.

And how is CO2 form Fe2O3 different than CO2 from the air? Is it just that it is easy to capture? Then what?

It's not different, but it's a pure gas and not mixed with a ton of nitrogen that air combustion exhaust would be. That makes it trivial to capture (literally just pump it through a compressor into a tank).

One important point, though, is that the sequestration problem is not actually addressed here. This just gets you conveniently-produced tanks of CO2 (or crates of dry ice, whatever). What you do with that to keep it out of the atmosphere is still an open problem.

Thank you, now it makes some sense. These press releases are next to useless.

Reply on news.ycombinator.com