Reply #30: These carbon sequestration schemes sound bogus [View All]

[FarCenter]

First you take carbon (coal for example).

Then you combine it with oxygen ( C + O2 => CO2 + heat ).

However, the only cheap source of oxygen is the air, which is roughly 4/5 nitrogen.

So C + O2 + 4 N2 => CO2 + 4 N2 + heat, since the nitrogen is mostly inert, although you can get some oxides of nitrogen if you have too much air.

Then you pass this hot exhaust gas through a boiler to heat water to drive turbines, etc.

This results in still-warm exhaust gas with maybe 25% C02.

So how do you cool this down, separate it from the nitrogen, compress it, and pump it into the earth without using more energy than you got out of burning the coal in the first place?