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Efficient method to capture carbon dioxide from the atmosphere

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Re: Efficient method to capture carbon dioxide from the atmosphere

#111

Post by mort96 »

saubeidl wrote: post #91
PeterHolzwarth wrote: post #84

Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture: It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively. In order, air is, broadly, made up of the following: Nitrogen: %78.084 Oxygen: %20.946 Argon: %00.934 CO2: %00.042 The stuff is essentially beyond a rounding error - it rea…

What if one started emitting Nitrogen, Oxygen and Argon in the right proportions instead to get the mix right again?

We will unquestionably reach more than twice the CO2 concentration of pre-industrial levels (which was around 280 ppm; we're at 424 ppm now, it'll increase to beyond 560 ppm in most not-super-optimistic projections).

Do you really think it's both feasible and a good idea to release so much O2 and N2 to double the mass of the atmosphere? Or even just increase it by some appreciable fraction?

For the record, the atmosphere is around 5 150 000 000 000 000 metric tons. 5 quintillion kilograms. You're talking about producing metric exatons of gas.

Wikipedia says that there's 300 000 to a million gigatons of nitrogen in the earth's crust; that's 300 teratons to a petaton (https://en.wikipedia.org/wiki/Nitrogen#Occurrence). If you extracted LITERALLY ALL THE NITROGEN IN THE CRUST, converted it to nitrogen gas and released it into the atmosphere, and we use the extremely optimistic 1 petaton estimate, you'd have increased the mass of the atmosphere by roughly 1/5000. That means you'd have decreased the CO2 concentration in the atmosphere ... by roughly 1/5000. From 424 ppm to 423.92 ppm.

Re: Efficient method to capture carbon dioxide from the atmosphere

#112

Post by mnky9800n »

cjbenedikt wrote: post #18
mnky9800n wrote: post #5

Earlier quoted context omitted.

you can inject it into peridotites and let it mineralize. there is enough exposed peridotite outcrops in the world that we could inject all the co2 produced and store it there indefinitely. this process also produces elemental hydrogen.

Do you have any links on research on that? Serious question.

Yes.

For example:

https://www.pnas.org/doi/10.1073/pnas.0805794105

Peter Kelemen has written a lot of papers on this topic.

Here is a more recent paper that I wrote together with Peter and others currently in review:

https://eartharxiv.org/repository/view/9651/

This is more about the mechanics of how the rock breaks to allow fluids to move around.

And here is another paper currently in review that we coauthored about how we know there’s gas moving in the system and therefore hydrogen is being produced:

https://essopenarchive.org/users/543018/articles/1363688-eni...

Tbh I have no idea why we didn’t submit these to arXiv instead of these other preprint servers.

Re: Efficient method to capture carbon dioxide from the atmosphere

#113

Post by bobfromhuddle »

jiehong wrote: post #68
condiment wrote: post #45

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes. Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s…

Could something like this be used to make cement? Imagine capturing CO2 to turn it into cement, used for constructions. Pardon my ignorance, though.

We don't use CO2 to make cement, we use limestone, and CO2 is the byproduct of heating the limestone to make reactive calcium.

Re: Efficient method to capture carbon dioxide from the atmosphere

#114

Post by jmward01 »

I am not against doing research in this area, please do, it is interesting and likely has many applications but global CO2 removal isn't one of them. Nothing proposed, including this, is within any orders of magnitude of a viable solution. The only solution we have is put less in the air in the first place. This tech looks interesting for transporting CO2 but that doesn't mean it sequesters it and even if sequestration was solved the scales here are massive. If we don't have the political will to reduce the amount going into the air then what makes anyone think we would have the political will to build out some system to capture and sequester? We need to focus more on not putting CO2 into the air and less on trying to take it out.

Re: Efficient method to capture carbon dioxide from the atmosphere

#115

Post by anotherpaulg »

saubeidl wrote: post #91
PeterHolzwarth wrote: post #84

Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture: It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively. In order, air is, broadly, made up of the following: Nitrogen: %78.084 Oxygen: %20.946 Argon: %00.934 CO2: %00.042 The stuff is essentially beyond a rounding error - it rea…

What if one started emitting Nitrogen, Oxygen and Argon in the right proportions instead to get the mix right again?

I like the unconventional approach. A few minutes with GPT raises two issues:

1. We've raised CO2 from 280ppm to 420ppm, about a 50% increase. To dilute it back down would require 50% more total atmosphere. This would also raise the surface air pressure 1.5x.

2. How much heat is trapped is related to the absolute amount of CO2 in the atmosphere, not the fraction. So the diluted atmosphere would retain just as much heat.

Re: Efficient method to capture carbon dioxide from the atmosphere

#116

Post by leobg »

PeterHolzwarth wrote: post #84

Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture: It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively. In order, air is, broadly, made up of the following: Nitrogen: %78.084 Oxygen: %20.946 Argon: %00.934 CO2: %00.042 The stuff is essentially beyond a rounding error - it rea…

So then, is it really the CO2 that produces the cognitive impairment, or is the CO2 here just the proxy value that we are measuring, and the real reason for the cognitive impairment is low oxygen?

Re: Efficient method to capture carbon dioxide from the atmosphere

#117

Post by nine_k »

jmward01 wrote: post #114

I am not against doing research in this area, please do, it is interesting and likely has many applications but global CO2 removal isn't one of them. Nothing proposed, including this, is within any orders of magnitude of a viable solution. The only solution we have is put less in the air in the first place. This tech looks interesting for transporting CO2 but that doesn't mean it sequesters it and even if sequestrati…

Sequestering CO2 where it's highly concentrated, e.g. at power plants or cement factories exhausts, would be one way to emit less.

Re: Efficient method to capture carbon dioxide from the atmosphere

#118

Post by Y-bar »

cogman10 wrote: post #31
roflmaostc wrote: post #4

Earlier quoted context omitted.

The problem is you cannot plant enough trees around the globe to offset our CO2 emissions. Also, a forest only absorbs CO2 while alive. Once it dies, it emits CO2 too. You would need to permanently store the wood somewhere (submerging in water, etc). Recent article: https://www.theguardian.com/environment/2025/nov/28/africa-f...

It's possible to permanently capture the carbon if you turn the wood into charcoal and ultimately bury or store that. But left out to rot and yeah, the fungus and bacteria will ultimately consume the wood and release CO2 as a byproduct.

You don’t need to convert it to coal. Use it to build houses, furniture, and other things.

I am currently building a wooden house this way. Wooden frame, wooden exterior, wooden floors, even wood-based insulation (https://huntonfiber.co.uk/). The isolation has the shortest life span and it is expected to last at least 60 years.

Re: Efficient method to capture carbon dioxide from the atmosphere

#119

Post by bluerooibos »

deadbabe wrote: post #108
_yb2s wrote: post #67

Earlier quoted context omitted.

I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air hea…

Ok this sounds like BS, what kind of sensor is being used to get such readings? What do you use?

I used an Awair Element after wondering if Co2 buildup was causing my groggieness in the morning and an ever so slight dull headache.

My bedroom was quite small at the time, but I measured the same effect of buildup in a larger bedroom, just the Co2 level took a little longer to reach it's peak.

In the small room it took about 45 mins to climb to about 1400 after I closed the door and went to sleep.

I'm currently trying to install some above-door vents to improve circulation but this is a topic most people don't consider at all, even though studies have shown the effects of classrooms having high Co2 concentrations on exam results and cognition.

Re: Efficient method to capture carbon dioxide from the atmosphere

#120

Post by jhpankow »

malfist wrote: post #90
lokar wrote: post #74

Earlier quoted context omitted.

Really? Wow, I try to keep my place at 500-600, without that much effort.

I find it extremely unlikely that homes are routinely at 2000-3000 ppm. That is extremely high and would mean multiple people in a small area with no air exchange for a long while. I monitor my indoor co2, but don't take any action because it's extremely rare to be above 700 or 800. I can only remember a handful of times its reached 1k ppm. And my house should be prime candidate for co2, it was built during the era o…

Homes in the upper midwest are well-sealed and insulated. Bedrooms can hit 2,000 ppm with two adults sleeping in them.
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