Making hydrocarbon fuel from CO2

[flatbutt]

A thread in PARF mentioned this topic:

"Why are we not ...snip...pulling CO2 from the air using late 1800s chemistry to make propane to run our vehicles and trains? Best bit is using CO2 already in the air makes that fuel a closed carbon source."

It is a neat bit chemistry. I do wonder about sourcing the H2. If water is the main source and we use electrolysis, would solar provide enough energy to support the enormously large-scale production needed?

Sourcing the H2 from water which is not an infinite supply is also problematic, but we need to start somewhere.

Any other nerdy types here familiar with this or have interesting input?

https://onlinelibrary.wiley.com/doi/10.1002/anie.201910579

[GH85Carrera]

Porsche is spending big bucks on exactly that technology. The energy needed to make the fuel is the hard part. If, like ethanol we use more energy (diesel) than we get back from the gas, what is the point. The corn farmers love having a full time customer, but only the huge government subsidies keep it in going.

Much like just using Hydrogen for fuel, great idea, just how do we get the hydrogen to burn. Same issues.

https://techcrunch.com/2022/04/06/porsche-synthetic-fuels-investment-sports-cars/

[island911]

Plants -those mostly green things everywhere- are constantly stripping the atmosphere of what little CO₂ the atmosphere has. The plants strip off the carbon and release the O₂ via photosynthesis. -a giant solar project established long before man that sequester carbon.

But let's pretend that CO₂ is a "pollutant" - a packaged absurdity for the ignorant.

[island911]

Internal combustion engines produce much more water vapor than they do CO₂ - Octane containing only 8 carbons, but 18 Hydrogen atoms.

Atmospheric water vapor is a MUCH larger "greenhouse gas" than is CO₂

Of course no one worries about looking for ways to pull water vapor out of the atmosphere, for one simple reason - rain.

Everyone knows that when too much water vapor accumulates it rains. -aka "Water cycle."

Yet somehow (massive propaganda campaigns) people don't know that atmospheric Carbon also cycles. - plants are quick to take any CO₂ they can grab. -note that CO₂ is pumped into grow-houses to gain crop yields more quickly.

[Arizona_928]

Called a fischer tropsch reaction.


In theory a scaled down version that could be ran on a wood stove is feasible.... but at that point mind as well run your big v8 on wood gas.



Limitations is it uses a lot of energy....

[Arizona_928]

Originally Posted by island911

Internal combustion engines produce much more water vapor than they do CO₂ - Octane containing only 8 carbons, but 18 Hydrogen atoms.

Atmospheric water vapor is a MUCH larger "greenhouse gas" than is CO₂

Of course no one worries about looking for ways to pull water vapor out of the atmosphere, for one simple reason - rain.

Everyone knows that when too much water vapor accumulates it rains. -aka "Water cycle."

Yet somehow (massive propaganda campaigns) people don't know that atmospheric Carbon also cycles. - plants are quick to take any CO₂ they can grab. -note that CO₂ is pumped into grow-houses to gain crop yields more quickly.

Just talked to a chemiker from a national lab on this. All they do is co2 research from dac. Final thought on the matter. Either you remove it, live through the "climate change", or move to a different area. Whatever.


I love the term fossil fuel. Hydrocarbons do not come from fossils. More of a mineral and very abundant one at that....

[flatbutt]

I had intended this to be a tech discussion not a political trash talk. I should know better by now.

[Arizona_928]

Originally Posted by Arizona_928

Called a fischer tropsch reaction.


In theory a scaled down version that could be ran on a wood stove is feasible.... but at that point mind as well run your big v8 on wood gas.



Limitations is it uses a lot of energy....

Originally Posted by flatbutt

I had intended this to be a tech discussion not a political trash talk. I should know better by now.

Not all political.

Lots of tech.

[red-beard]

TANSTAAFL - There ain't no such thing as a free lunch.

Combining CO2 with Hydrogen to make methane (or any other hydrocarbon) takes energy,

CO2 is by definition zero.
H2O is by definition zero.

H2 is 286 KJ/Mol
CH4 is 891 KJ/Mol

CO2 + 2*H2O = CH4 + 2*O2 + 891 KJ/Mol (added energy)

If you started with Hydrogen, it would be 572 KJ less, but you still need to make hydrogen.

And that assumes no losses in the reactions, which is never the case.

[Arizona_928]

891kj/mol

Lol. That's a hell of an enthalpy....



That's 4/5 times as much as the energy to wash co2 with amines....

[red-beard]

Yep. It takes energy to make hydrocarbons.

[island911]

Originally Posted by red-beard

Yep. It takes energy to make hydrocarbons.

If only there was some natural, renewable way; like using solar... something green! - like this text is implied to be.

[GH85Carrera]

Originally Posted by red-beard

Yep. It takes energy to make hydrocarbons.

Now you went and threw in physics and laws of thermodynamics. We just need to invent a way around those laws!

We need us some Dilithium Crystals and antimatter! That will be the answer.

[Arizona_928]

Originally Posted by GH85Carrera

Now you went and threw in physics and laws of thermodynamics. We just need to invent a way around those laws!

We need us some Dilithium Crystals and antimatter! That will be the answer.

Just use a catalyst to lower activation energy....
or magic.... or something...

[red 928]

It's not enough to live in just a half-pretend world.
But every time we get past the halfway point
someone jumps in with real stuff and screws up
all that progress.
I hate that