[rhelz]

The application you mention does not rely on the gas being co2 at all. The gas is being used because it is in a high pressure reservoir. It could by any gas. The C02 itself is literally free because it is literally in the atmosphere all around us.

[ewhanley]

Pressure is only part of the equation. The pressure gets it to the field economically and does boos reservoir pressure, but co2 injection has more to do with miscibility with hydrocarbons at relatively low pressures. Miscibility yields viscosity reduction and swells the oil to improve displacement and mobility, particularly in heavier crude. Couple that with pressure and you can dramatically improve recovery factor.

[telgareith]

That sounds like a lot of it ends bound to, and thus comes up with, the oil/crude.

[ewhanley]

It absolutely does and has to be stripped out in processing. It typically gets compressed and reinjected over and over again

[alach11]

Exactly. And getting back to the original poster's comment "the CO2 starts underground and ends up underground"... that assumes there are no leaks anywhere in the process.

[kaibee]

> The C02 itself is literally free because it is literally in the atmosphere all around us.

Not exactly.

> The concentration of carbon dioxide (CO 2) in the atmosphere reach 427 ppm (0.04%) in 2024.

Any process that tries to unmix something is not going to be 'literally' free. And given the relative trace amounts we're talking here...

[rhelz]

That was exactly my point. What makes the co2 referred valuable is not that it is co2. We literally (not metaphorically, or hyperbolically, but literally) are surrounded by the stuff every day of our lives.

What makes it valuable is that the co2 is concentrated and under pressure. But pretty much any gas would fit the bill.

And let's not forget, the original article was about MIT scientists making extracting co2 from the atmosphere "more efficient". Which, as you point out, is a rather hopeless quest---in order to get the co2 back out of the atmosphere, you'd need more energy than you got from burning whatever put it there in the first place.

So making any meaningful dent in the atmospheric co2 by extraction/converting a mug's game. You'd need on the order of the entire amount of energy used by the human race during the entire industrial age.

[0cf8612b2e1e]

CO2 may be everywhere, but it is at a very low concentration. Efficiently isolating CO2 from the rest of the gases is a limiting factor.

[rhelz]

Exactly my point. The original comment claimed that the co2 itself was valuable. It is not. What is valuable is that it is concentrated and under pressure.