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Half a pound of this powder can remove as much CO2 from the air as a tree

latimes.com

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Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#21

Post by entropicdrifter »

BizarroLand wrote: post #12
floxy wrote: post #5

Earlier quoted context omitted.

>how you would sequester the gaseous CO2 other than "put it underground." I wonder if there is a reason you couldn't just sequester the powder. Probably too expensive? Or not volume efficient? >to leak out eventually due to plate techtonics This might seem shortsighted, but I'm OK pushing the problem out by 50 million years or so.

Since the powder is reusable, it likely wouldn't make sense to sequester it with the CO2 either materially or financially.

This. The powder is more efficiently used as a way to move the CO2 around than as a means to keep it sequestered.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#22

Post by jjk166 »

hansvm wrote: post #9
kazinator wrote: post #7

> As it entered the tube, the Berkeley air contained CO2 in concentrations ranging from 410 ppm to 517 ppm. When it came out the other side, the scientists could not detect any carbon dioxide at all, Zhou said. This sounds like it could be the basis for a respirator-like breathing apparatus, not requiring tanks, for entering and staying in enclosed spaces where the concentration of CO2 is high. (Provided there is eno…

That feels super dangerous. CO2 is mostly fine to breathe, but it triggers the impulse to breathe. Without it you won't feel that you're running out of oxygen.

You produce the CO2 that causes the impulse to breathe. That's what you are exhaling.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#23

Post by hansvm »

surfpel wrote: post #19
hansvm wrote: post #9

Earlier quoted context omitted.

That feels super dangerous. CO2 is mostly fine to breathe, but it triggers the impulse to breathe. Without it you won't feel that you're running out of oxygen.

That's CO2 IN the blood that "triggers breathing". Unless you plan to inject the powder, that's not really an issue.

What I mean is that scrubbing the CO2 leaves you in a scenario where the air is just as dangerous as before (no oxygen) but you don't have any reflexes or senses letting you know of the danger.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#24

Post by jjk166 »

doctorwho42 wrote: post #3

So it acts like a reusable CO2 trap, then releases said CO2 at the cost of heating it up to 140F. Which then releases it. It doesn't really talk about how you would sequester the gaseous CO2 other than "put it underground."... But if you put a gas underground it will eventually leak out. Even a liquid is prone to leak out eventually due to plate techtonics, but a liquid doesn't immediately turn into gaseous CO2. So t…

Many common minerals like olivine react with CO2 at high concentrations to form carbonates which are geologically stable. The issue is getting the high carbon concentrations to make this process fast. Concentrating CO2 is the major technical hurdle of carbon sequestration.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#25

Post by jjk166 »

gus_massa wrote: post #17
BizarroLand wrote: post #10

Earlier quoted context omitted.

If you can extract ~100% pure CO2 from the powder, then it might be feasible to develop a process that can convert very dense CO2 into Carbon and Oxygen. Carbon is about 3/8ths of the total weight of a CO2 molecule and is solid and relatively inert at room temperature and pressure. Of course, if there were a convenient way to simply strip carbon off of a CO2 molecule to begin with that would be the ideal system, but…

> Plants do it, after all. It's not impossible. The problem is that to reverse CO2 -> C + O2 you need the same amount of energy that you get burning coal C + O2 -> CO2. But burning coal, like half of the energy is lost as unuseful heat. The reaction of plants is different, but plants only has a 2% of efficiency. The chemical reaction of plants is more complicated, so let's be optimistic and assume this reaction has a…

There are reasons you would want to use fossil fuels and use renewables to reverse the process. Fossil fuels have high energy density, can be transported and stored with minimal losses, and consumed anywhere anytime. There are lots of things that are difficult to directly electrify like say planes. You can't simply stick a bunch of batteries on a plane to replace a jet engine and its fuel tanks. But building an excess of solar panels on the ground to mop up the CO2 equivalent of the jet engine's exhaust is simply a matter of cost. E-fuels are basically just really dense chemical batteries.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#26

Post by doctorwho42 »

glial wrote: post #18
jiggawatts wrote: post #14

Earlier quoted context omitted.

Plants do it using the energy from the sun. All of these “can’t we just unburn burnt things” forget that the reason we burnt the carbon in the first place was to get that energy. Unburning it would need to return that energy and more because of inefficiencies. If you have energy to spare, you don’t need to burn the carbon in the first place. With global fossil fuel usage still rising, we clearly don’t have any to spa…

It's not so clear to me -- the MIT Technology Review is already wringing its hands about energy being so cheap it causes problems with economics. [1] https://www.technologyreview.com/2021/07/14/1028461/solar-va...

Energy can be economically cheap in the current paradigm, while also being insufficiently cheap or insufficient quantities of clean energy to make the above comments suggestion work.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#27

Post by hansvm »

jjk166 wrote: post #22
hansvm wrote: post #9

Earlier quoted context omitted.

That feels super dangerous. CO2 is mostly fine to breathe, but it triggers the impulse to breathe. Without it you won't feel that you're running out of oxygen.

You produce the CO2 that causes the impulse to breathe. That's what you are exhaling.

Right, and you want that. Scrubbing the CO2 without adding oxygen leaves you in a state where the air is useless and your body can't tell.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#28

Post by _yb2s »

kadoban wrote: post #16
_yb2s wrote: post #8

Earlier quoted context omitted.

I suspect that previously acceptable building designs now cause cognitive decline because of much higher outdoor CO2 levels- it’s a bigger problem than people realize. I live in a mild climate where I can just keep the windows open year round- but when the neighbors have a loud party I close them to focus or sleep and CO2 will quickly climb to over 2000ppm, well over the 1400 or so that causes measurable negative eff…

This is definitely a real problem, but it's not caused by higher outdoor CO2 levels. The levels outside are typically in the 400-500ppm range. When you're enclosed with not enough ventilation, the issue is you (and other breathing organisms) and the lack of ventilation, not the outdoor level. The outdoor level has absolutely risen, it's just not the important factor here. You're very lucky that you can keep windows o…

I disagree- many people, especially in Europe are still using buildings designed in pre-industrial times, when CO2 levels were as low as half what they are in urban areas now. Those buildings now will have much higher CO2 levels indoors than when first built, with the same amount of air exchange. One could estimate exactly how much higher with some differential equations, but certainly in some cases it is possible to push things over the limit where there are now problems, everything else remaining the same.

Moreover, those buildings likely now have much less air exchange than when designed now that they use AC instead of open windows, forced air heat instead of unsealed fireplaces (which turn over a lot of air), and possibly have been updated to more airtight doors and windows.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#29

Post by Zenzero »

hansvm wrote: post #9
kazinator wrote: post #7

> As it entered the tube, the Berkeley air contained CO2 in concentrations ranging from 410 ppm to 517 ppm. When it came out the other side, the scientists could not detect any carbon dioxide at all, Zhou said. This sounds like it could be the basis for a respirator-like breathing apparatus, not requiring tanks, for entering and staying in enclosed spaces where the concentration of CO2 is high. (Provided there is eno…

That feels super dangerous. CO2 is mostly fine to breathe, but it triggers the impulse to breathe. Without it you won't feel that you're running out of oxygen.

Any context in which it is being used as a scrubber would be one where the people designing it would 100% be aware of this.

Re: Half a pound of this powder can remove as much CO2 from the air as a tree

#30

Post by telgareith »

hansvm wrote: post #9
kazinator wrote: post #7

> As it entered the tube, the Berkeley air contained CO2 in concentrations ranging from 410 ppm to 517 ppm. When it came out the other side, the scientists could not detect any carbon dioxide at all, Zhou said. This sounds like it could be the basis for a respirator-like breathing apparatus, not requiring tanks, for entering and staying in enclosed spaces where the concentration of CO2 is high. (Provided there is eno…

That feels super dangerous. CO2 is mostly fine to breathe, but it triggers the impulse to breathe. Without it you won't feel that you're running out of oxygen.

That assumes you're breathing something besides pure oxygen.

And the "device" is called a 'rebreather.' https://en.m.wikipedia.org/wiki/Rebreather

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