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Engineers find neat way to turn waste carbon dioxide into useful material

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Re: Engineers find neat way to turn waste carbon dioxide into useful material

#81

Post by perl4ever »

readams wrote: post #51
perl4ever wrote: post #41

Earlier quoted context omitted.

I do not understand the concept that a property of a sum of a bunch of numbers somehow applies to those components. Whether something is net zero depends on what you are adding it to; it's not inherent in that thing. It's like, if you have a pile of blue things, then the pile is also blue. But other characteristics do not work that way. If you have a pile of things that each weigh 1 lb, then the pile does not weigh 1…

If you make a hydrocarbon by taking CO2 from the air, and you use a carbon free energy source to do it, then burning that hydrocarbon is net zero carbon. That is, if all your hydrocarbons that you burn were made this way, then the atmospheric carbon doesn't increase because of your activity. It acts just like a battery.

You're not telling me anything I don't know.

Look at it this way, do you believe CO2 is basically fungible in the context of global climate change?

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#82

Post by LegitShady »

twic wrote: post #77
LegitShady wrote: post #42

Earlier quoted context omitted.

>Use the excess summer power to fill up a near empty dam with desalinated water? Pumped storage hydroelectricity is the biggest form of power storage at the moment, and has efficiencies around 70-80%. The losses for desalinization (pumping through media) are ruinous compared to just pumping uphill, and storing desalinized water means you can't use it without spending potential power. There might be good reasons not t…

I think the idea here was simply to use the excess energy to stock up on potable water, which people could drink later, rather than to also use it for pumped storage.

> I think the idea here was simply to use the excess energy to stock up on potable water, which people could drink later, rather than to also use it for pumped storage.

If it was a reasonable and profitable use of energy we would already be doing it, but we're not because its ruinously expensive. You also run into storage issues (how much of your excess power is being evaporated from the surface of your storage reservoir? The longer you hold your potable water the more you throw away). You also need to consider what you're going to do with the highly saline byproduct of any such process.

There's nothing wrong with purifying water but its very energy intensive and already something we do. Adding more expensive potable water from excess energy generation doesn't make much sense.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#83

Post by LegitShady »

PopeDotNinja wrote: post #50
LegitShady wrote: post #42

Earlier quoted context omitted.

>Use the excess summer power to fill up a near empty dam with desalinated water? Pumped storage hydroelectricity is the biggest form of power storage at the moment, and has efficiencies around 70-80%. The losses for desalinization (pumping through media) are ruinous compared to just pumping uphill, and storing desalinized water means you can't use it without spending potential power. There might be good reasons not t…

As I understand it, the main challenge with pumped storage is that you can't do it everywhere. You need fairly specific geography for it, and it's a big civil engineering project. Here's a good video on by Practical Engineering: https://youtu.be/66YRCjkxIcg

> You need fairly specific geography for it, and it's a big civil engineering project.

You need elevation difference and fairly stable soil. Everything else is technologically solveable. It's a big civil engineering project but its a profitable one and not particularly challenging.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#84

Post by LegitShady »

MaxBarraclough wrote: post #61
PopeDotNinja wrote: post #50

Earlier quoted context omitted.

As I understand it, the main challenge with pumped storage is that you can't do it everywhere. You need fairly specific geography for it, and it's a big civil engineering project. Here's a good video on by Practical Engineering: https://youtu.be/66YRCjkxIcg

Good video, thanks. It briefly mentions the idea of pumped seawater storage. Is that really any different from using freshwater, other than location?

seawater is saline, you have to be careful what you do with it because you dont want to literally salt the earth where you are (soil remediation friggin sucks).

seawater is also not valuable. You don't care about the water quality in the reservoir, you just let it fall back into the sea. If it evaporates you're losing energy but you aren't losing potable water that you sell, and it doesn't require a connection to a water distribution main.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#85

Post by mulcyber »

gpm wrote: post #48
marcosdumay wrote: post #46

Earlier quoted context omitted.

If you are concerned about indoor CO2 concentration, the answer is to ventilate the place. No reasonable amount of plants will keep a house stable. If it's just really curiosity, well, people have been scrubbing CO2 since space travel is a thing. Wikipedia was completely unhelpful to me, but I remember there is a mineral with high CO2 selectivity that you can simply push the air though it.

98% curiosity, 2% lack of faith in our long term ability to keep CO2 levels down to healthy levels (1000ppm is enough that we can detect minor negative effects... I have to wonder if really minor ones exist even at 400 ppm). Wikipedia was similarly not useful for me. Scuba divers and the like apparently use a one-time-use non-regenerative mineral that absorbs CO2. The space station has something that regenerates but…

Casual technical diver here. It's lime (maybe something else sometime, not 100%).

The process of making lime from limestone actually produces CO2, so it's use in CO2 scrubbers are more or less carbone neutral.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#86

Post by mulcyber »

gpm wrote: post #24

Slightly offtopic, what's the easiest way to scrub CO2 from air (e.g. in a house) without using up consumable materials? Some form of pressure swing absorption?

Casual technical diver here. It's lime (maybe something else sometime, not 100%).

The process of making lime from limestone actually produces CO2, so it's use in CO2 scrubbers are more or less carbone neutral.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#87

Post by 08-15 »

twic wrote: post #78
08-15 wrote: post #76

Earlier quoted context omitted.

The article provokes these replies by prominently making this absurdly stupid statement: This technology could be retrofitted to coal fired power plants. No, it can't! The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available. It might work for a cement kiln, but not for a power plant. I'm sure you know that. But the idiot who p…

> The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available. Unless you have some way of buffering the CO2. Biologically, this is what CAM photosynthesis does [1], and i have a vague memory of there being an industrial equivalent. Something like dissolving the CO2 in calcium hydroxide, to make calcium carbonate, then later on sp…

I was sort-of hoping for this comment. What it boils down to is, what is easier? Storing hydrogen, or storing both CO2 and a hydrocarbon, or is there another way? With lots of caveats, because the chemistry isn't exactly the same. (I think there is another way, and it's ammonia and/or hydrazine.)

> Something like dissolving the CO2 in calcium hydroxide

That's terrible. Calcium carbonate needs to high heat to release CO2. Unless you want to leave CaCO3 well alone (that's the enhanced weathering concept), this is approximately the last compound you want to make. Simply storing liquid CO2 under pressure (80 bar or so? not nice, but doable) sounds much more appealing. (Ammonia is better in every respect, though.)

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#88

Post by leoedin »

adrianN wrote: post #66
leoedin wrote: post #62

Earlier quoted context omitted.

> we simply don't have enough space for wind and solar to feed our thirst for hydrocarbons with renewable power. I'm not sure if this is the case or not. To give some numbers: Current global oil consumption is 54225 TWh, or 6.2TW [1] Current global solar panel generation capacity is 628 GW (2019) [2]. Median capacity factor maybe 25% [3] Current global wind power capacity is 650 GW [4]. Median capacity factor maybe ~…

Thanks for doing the math. On a global scale it does look better than the math I did for Germany. However, I think 50% process efficiency is too high. High temperature electrolysis is about 60% efficient, but then you only have hot uncompressed hydrogen. There are a number more steps involved to get to a liquid fuel, each of them with considerable losses. I can't find the sources right now but I believe I remember so…

Yeah, it probably is. There's not really a nice process for making liquid fuel - hydrogen isn't a great fuel really. My understanding is that the biggest problem with making a practical liquid fuel is ironically getting the carbon. Hydrogen is in water, but carbon is only really in carbon dioxide - which is at very low atmospheric concentrations and so takes an incredible amount of energy to capture.

Ammonia would be easier (ubiquitous nitrogen everywhere), but isn't a particularly nice fuel either. At least it's easier to store than hydrogen.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#89

Post by namibj »

swiley wrote: post #71
namibj wrote: post #57

Earlier quoted context omitted.

Not really without consumables, unfortunately. But it's easy and costs about 50-200$ per human and month when you just buy the required substance, granular CaOH treated with 1~2 NaOH (by pouring a concentrated solution of it over the CaOH), from Alibaba once a year. That stuff is e.g. used for re-breathers in anesthesia. CAS 8006-28-8 is the "magic" word/number. The potential alternative, which would not use consumab…

Now you have caustic soda laying around and potentially being aerosolized, I’m not sure that’s an improvement.

It's used in medical anesthetic ventilators, so not sure where you get your worries from.

Re: Engineers find neat way to turn waste carbon dioxide into useful material

#90

Post by travisporter »

effie wrote: post #38
travisporter wrote: post #32

Earlier quoted context omitted.

It’s actually strange that no gas company is advertising something like this. I’ve seen so many industries advertise even the tiniest carbon offsets but why can’t BP or Exxon sell a net zero or at least low emissions fuel

It is really strange to you that oil company is not advertising a product that they don't have, a product which would compete with their regular product, a product which is hard to sell (more expensive and dubious value)? From the standpoint of these companies, there is plenty of oil down there, making synthetic one has no upside.

Well, maybe not synthetic, but what if they said "use this gas for 10% more, we planted a tree for every gallon" or whatever. Even if it was complete bs, I'd think about it
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