Carbon Removal 8

[Carbodynamics]

thread730-443054
CO2 can be removed from the atmosphere and separated into solid carbon and oxygen gas. Essentially unburning carbon.
Switching to renewable energy sources will reduce CO2 emissions however it won't remove excess CO2 in the atmosphere as a result of the combustion of fossil fuels.
2Mg + CO2 ⇌ 2MgO + C
Solid carbon submerged is relatively inert and compact.
Electrolytically recovering the Mg and collecting CO2 will require energy from renewable sources. This is the mechanism that I propose. Does anyone have any arguments against using it to sequester atmospheric CO2?

 

[Carbodynamics]

 

[Carbodynamics]

 

[Carbodynamics]

Q - kiln MgCO3⇌MgO+CO2
R - pure CO2 tank
J - Molten MgO
K - carbon anode
L - molten metal cathode
O - CO2 injection site
M - carbon to be submerged H2O

 

[3DDave]

Good - the Mg is all sorted out. 1 Million metric tons is the entire world's annual production.

Where's the energy coming from? You seem to have skipped that part.

And where does the cooling come into play - all that superheated material needs to be cooled somehow. Where does that heat go?

I do like the part where the carbon "should" float up. Seems like an easy experiment to run before committing to this technology.

 

[Carbodynamics]

Density MgO 3.58
Density C 3.52
Kind of close but might be enough.
Energy can be solar, wind, geothermal, hydro, tidal, perhaps nuclear.
I don't think we can afford cooling. Don't want to lose energy in the MgCO3⇌CO2+MgO reaction. Want to recover energy from 2Mg+CO2⇌2MgO+C for electrolysis of MgO.
At 100% efficiency CO2⇌C+O2 393.5 kj/mol is the net reaction.
100% isn't realistic. No reason to settle for an arbitrary efficiency number unless there is a physical law that dictates.

 

[Carbodynamics]

This is just a machine. We're good at building machines.

 

[Carbodynamics]

@greglocock can you suggest a more appropriate site.

 

[Carbodynamics]

@mintjulep yes I agree. I question the neutral philosophy of carbon fuel production. Sequestration of O2 in the CO2 isn't the correct solution. We aren't even addressing the O2 in H2O from combustion. Who would have thought that we could influence the amount of CO2 and O2 in our bubble?

 

[miningman]

Suggest the OP studies the Magcan plant , just south of Calgary. Metallic magnesium was produced from MgCO3 Rock. Place went bankrupt despite very large subsidies from the government.

 

[3DDave]

The sun provides roughly 10,000 times current human energy production. To make this a 30 year project takes 10% of that power level - so humans need to find a source that is 1,000 times larger than is in current use. Since wind and hydropower are solar powered, tidal has definite limits (it draws power from the Moon's orbital energy; how much before that changes?) that leaves nuclear (not happening, they keep going off line for a bunch of technical reasons) that leaves geothermal to get about 100,000 times more than it does now.

Even a 300 year project is 100 times the current energy production. That's not going to happen.

Density MgO 3.58
Density C 3.52

Is that at the process temperature for the MgO and is there proof of that? What is the solubility of carbon at the process temp? Should you have already demonstrated this on a smaller scale?

The water in Alberta should be checked. There's too much LSD leaking in.

 

[Carbodynamics]

@miningman yes sounds like I've got a good source of MgO near Radium. I've read a bit about that project.
Carbon removal to correct the excess in the atmosphere is going to be a difficult sale. I seems like governments are providing incentives and directives to reduce CO2 emissions. It's going to be harder to find someone to buy the pile of carbon beside my electrolytic tower.
Magcan didn't fly. I'm not trying to produce Mg. It's just part of a mechanism to ionize CO2 and scavenge the O2.
When society buys into a working mechanism they'll be buying wellness not carbon submerged in an old coal mine. This isn't going to be free. Photosynthesis used to be free. We are taking that off the table. I don't think we are going to be able to hydrospore the world with photosynthetic yeast to reverse a bad decision to use combustion.
I think we are going to have to build reactors, expend energy, and pay for it.

 

[Carbodynamics]

@3ddave that's what I was hoping for. I needed to bounce this off of people with expertise to test the logic.
So unsound mechanism and not enough energy in the world to do it. I actually thought it was possible. At least now I can stop.

 

[GregLocock]

" humans need to find a source that is 1,000 times larger than is in current use"
I wonder if that might have any side effects? How much concrete and steel do you need for this?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Carbodynamics]

2019
world energy kwh/yr
1.71E+14


Gt Carbon
655


tonnes Carbon
6.55E+11


kwh/tonne
9110






total kwh needed
5.96705E+15


kwh/yr 30 yr
1.98902E+14


fraction world yr production
1.16E+00


solar available kwh/hr
1.19444E+14


solar available kwh/yr
1.04633E+18


fraction solar yr available
0.000190094


area half earth surface sq m
2.55E+14


area required sq m
48473964638


m long m wide
220168.0373


width equatorial solar panels in m
2419.162303


Sorry I gave up too soon.
Big numbers.
And yes I should have done the math.
3 km wide around the earth.
About 7 sq m of panels per person at 100%

 

[3DDave]

https://imgur.com/gallery/m5vbxKF

 

[Carbodynamics]

 

[moltenmetal]

C'mon- the obvious solution here is just to turn all that CO2 into diamonds and oxygen!

Small thermodynamics problem there, but that's all just details! There's plenty of energy from the sun!

Sorry folks, but it's tough to take any of this stuff seriously. The very reason we make CO2 as a product of energy producing reactions is the same reason it's a difficult feedstock, in energetic terms, to make anything of value from- even if you're satisfied with making artificial coal instead of diamonds.

 

[geotechguy1]

For carbon sequestration it might be more effective to capture the CO2 at the source; eg. Shell's Quest carbon capture project captures about a third of the CO2 emitted by the scotford upgrader in Alberta.

For removal from the atmosphere, plant trees. Build things out of the trees. Plant more trees. Bury the things you built out of the trees when they are no longer useful?

 

[moltenmetal]

Better still make char from the waste trees or tree derived stuff and bury that, using the pyrolysis oil and vapor as a fuel to replace the transport uses that can't be electrified. Shell/GTIs IH^2 process is particularly good.

Especially don't burn or convert waste plastics to fuels to burn- recycle what you can and bury the rest. Plastics are 200% fossil origin and landfilling them is the cheapest and lowest impact post consumer fossil capture imaginable.

(

http://www.spitfireresearch.com)

 

[cranky108]

As I burn wood for heat, I have been told many times that wood is such a dirty fuel source. Why don't you use natural gas?
I normally have charcoal as a waste as the fire ends late at night. This gets landfilled.

I think we should do the easy things first. Biogas is nearly 50% methane, and nearly 50% CO2. And since real natural gas must be processed to remove other gases, and to blend it, the biogas can be a stand in for real natural gas. The CO2 can be used for many things, including improving plant growing in green houses.
Or the biogas can be used as a heating fuel in greenhouses directly, in what has been called suicide heaters.

So why start with Rup Goldberg projects?