Liquid Gallium Shown to Break Down Carbon Dioxide – Sci-News.com
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They used 6%-20% CO2 mixtures with balance nitrogen and some water to try and approximate different exhausts including flue gas.
This seems like a groundbreaking achievement. The only thing that wasn’t clear to me was the size of reactor they expect to be required to achieve meaningful throughput, and the amount of HCl replenishment required, if any, to maintain catalytic performance.
This paper gives me a lot of hope.
They estimated $100 cost for ~500 lbs of carbon.
To put things in context, there's about a trillion tons of "excess" co2 in the atmosphere.
That means you're going to need to produce 280 million tons of carbon to reset to 1970 levels.
$400 per ton means $1,120,000,000 , or $1.12 trillion.
Assume economies of scale, improved efficiency, secondary markets, and you could reduce the effective cost by 80%, so maybe $250 billion could solve co2 climate impact.
Spread that out over all vehicles, power plants, businesses, and so on, and that seems achievable over a decade. Spread over global scales on a sound 50 year plan, and people wouldn't even notice any economic impact.
Now what if you can tweak the chemistry and produce methane or ethanol or propane? Pure carbon feedstock has to have more uses, so it might be a net producer of value, as opposed to a fundamental cost.
Pretty exciting to think about.
That's practically nothing. This is very hope inspiring: when politics eventually catches up to science we may actually have the tools to do something in time.
From the paper:
"We have already scaled this system up to two-and-a-half liters dimensions, which can deal with around 0.1 liter of CO2 per minute. And we've tested that running continuously for a whole month and the efficiency of the system did not degrade."
2.5l column runs 6 liters per hour.
494,109.34 Liters per ton of co2, so... lots of columns are needed. 82,352 columns per ton per hour, lol.
If you made a giant pool reactor it would be 206 cubic meters of space, so 15x15x1 meters, or about 50x50 feet.
This could greatly improve the efficiency of burning coal.
Let's say you burn a ton of coal, (assume pure carbon for this example) getting 2460 kWh of power, per ref: [1]
You then put the resultant 3 2/3 ton of CO2 through this process, at a cost of 843 kWh, recovering 920 kg of carbon.
You've now consumed net 80 kg of carbon, generated 2460-843 --> 1617 kWh of electricity, for a net of 20,212 kWh/ton of Carbon burned.
This page [1] says a ton of coal gives 2460 kWh of electricity
1 - https://www.mcginley.co.uk/news/how-much-of-each-energy-sour....
However, reading the original paper, it seems like the end product is "highly oxidized carbon", "akin to that of slightly crystalline graphene oxide". So they're not claiming to undo the carbon oxidization, more to vitrify the carbon oxide in a solid phase. This, presumably, takes significantly less energy than reducing the carbon.
2460 kwh, at 12 cents per kwh, translates to $295 of electricity per ton. It optimally produces twice as much as it consumes.
Maybe a Stirling engine that uses a belt feeder, with the flakes skimmed from the catalytic reaction chamber onto the belt, drying in the heat of combustion, then dropped into the burner, and the exhaust bubbled back into the solvent. Then it could deposit the excess flakes while producing power by directly consuming co2?
This is pretty phenomenal, edging into the "too good to be true" domain.
Anyway, pointing out that pure carbon can be burned is good thinking.
Couldn’t you then burn the carbon and oxygen you created to get out more lower than you put in?
It looks like it's not pure carbon that is produced but a variation of graphene oxide, though, which can't be a easily burned to maintain the reaction. It can be reduced, and then burned, though, so there's still potential for a co2 power cycle.
Way above the ~$18 price tag California puts on a ton of carbon. But this method has the benefit that it returns oxygen to the atmosphere instead of locking it away, bonded to carbon, for eons.
Perhaps added incentives can be made to methods that not only sequester carbon, but also return oxygen back to the the atmosphere.
None of these are in any way constrained by the concentration of oxygen.
The carbon dioxide in the atmosphere is 0.04%. The amount of captured carbon that will be broken down through technology will be a fraction of this. It is unlikely to change the concentration of oxygen in anyway.
I can burn some coal, turn C and O2 into energy and CO2, then use a fraction of the energy to split it back into C and O2 and be left with some energy still (quite a bit apparently). So I can repeat as much as I like.
What am I missing?
I tried googling around, but the only hits I get are for dry ice, which this clearly isn't.
I guess the key concern with CO2 is that it gets vented into the atmosphere. If we could solidify it, we could stick it back into the mines and that's one problem off our list.
Until all the coal burning power plants are shut down, that 230kwh is almost certainly better used displacing some coal. If it didn't already come from coal.
1.13 kw/h per pound of coal burned.
260 lbs of coal enables processing of 1 ton of co2, of which about 500 lbs is captured as carbon flakes.
You could burn coal, producing 525 lbs of co2 for the energy needed to process 1 ton of co2 in total, so you end up capturing 375lbs more carbon than is produced. 125lbs of the carbon flakes come from the coal, the other 50 lbs of carbon in the coal is lost as byproducts and inefficiency.
So running this process, even on pure coal, sequesters 2.75 to 3 times as much carbon as it produces as co2.