If EVs are in fact burning coal... better do it right!

[freebeard]

These processes require input to start up, but then become self-sustaining. See also:
https://en.wikipedia.org/wiki/Thermal_depolymerization.

[cRiPpLe_rOoStEr]

I was already quite familiar to terra preta, not to scientific aspects around it. Anyway, maybe some solar "oven" could be a good way to avoid the need to waste other fuels while making charcoal that would be used to make terra preta, but for usage as a fuel I still consider raw wood to not be bad at all as it would be overall less energy-intensive even though its energy density is reported to be lower compared to charcoal.

[NeilBlanchard]

Yes, rotting plant matter returns all the carbon to the air - by definition. That is part of the cycle of life, and proves the laws of conservation.

The point of making biochar (which is fully activated carbon, made at higher temperatures than charcoal) is that you do NOT burn all of the carbon, and put what carbon you can in the soil.

When you do pyrolysis, you gasify all the volatile material out of the wood, and that releases more of the energy than low temperature burning does. It produces almost no smoke, and ideally it only produces carbon dioxide.

You "sacrifice" about half (or a bit more) of the wood to heat the remaining material, that becomes the biochar.

I made the simplest retort, and I have done three burns, so far:

https://www.youtube.com/watch?v=VKR-kqTKypw

The inner barrel I have is ~20 gallons while ~30 gallon is a better size. At first, I had too much primary air, and it burned very hot, but didn't last long enough. My third burn was ~3 hours, which is still on the short side, but I got good quality biochar, with a glass-like sound - see the video.

My challenge now is how to use the heat - I want to collect heat from the flue, with a water jacket, and I'd like to try a Peltier to generate some electricity. As you can see, I tried cooking on it, but I need to get solid contact surface - and I now have a heat shield to keep my legs from scorching!

[redpoint5]

Originally Posted by NeilBlanchard

Yes, rotting plant matter returns all the carbon to the air - by definition. That is part of the cycle of life, and proves the laws of conservation.

...I'd like to try a Peltier to generate some electricity.

To continue the hijacked tangent thought; that means carbon in dead plant matter is only sequestered long-term if it somehow immediately gets buried, is deprived of oxygen, and never decomposes? That means fossil fuels are the extremely small portion of previous plant / animal matter that expired, but did not decompose, and instead was subjected to high pressure without oxygen?

...the Peltier would be neat, although inefficient. I played around with one back in the Pentium II days as a means of forced cooling of the CPU, but it was terribly inefficient and generated massive amounts of heat in the process.

[freebeard]

I made the simplest retort, and I have done three burns, so far

Good for you. What do you have as a source of biomass?

That means fossil fuels are the extremely small portion of previous plant / animal matter that expired...

We're veering into Unicorn Lounge territory here; but an alternative theory is hot, abiotic oil, made from rocks.

[IamIan]

Originally Posted by redpoint5

To continue the hijacked tangent thought; that means carbon in dead plant matter is only sequestered long-term if it somehow immediately gets buried, is deprived of oxygen, and never decomposes? That means fossil fuels are the extremely small portion of previous plant / animal matter that expired, but did not decompose, and instead was subjected to high pressure without oxygen?

Or ... if the decomposition does not run 100% complete all the Carbon back out to the surface .. which is what actually happens .. it isn't 100% surface back to surface.

For example:
#1> If it were 100% there would never be any production of 'new' soil .. soil amounts would only be static or lost .. That isn't the case .. there are places that produce more soil .. the decomposed plant/animal carbon did not all end up immediately returned back up .. it just gets buried deeper and deeper by more and more layers of new soil on top of older new soil.

#2> There is the carbon of dead animals and plants that fall to the very bottom of the ocean .. down where there isn't light from the surface .. further down than any surface fish swims ... extremely low levels of oxygen .. that carbon doesn't normally come back up to the surface in the normal decomposition cycle alone .. that carbon gets back up eventually long term from volcanic vents , eruptions , or it gets subducted under another continental plate .. to eventually long time later get released something else .. geysers , volcanoes , etc.

etc.

I don't have the exact % you asked for .. but it is not 0% .. and it is not 100% .. neither of those would agree with the world we see.

[IamIan]

Originally Posted by NeilBlanchard

Yes, rotting plant matter returns all the carbon to the air - by definition. That is part of the cycle of life, and proves the laws of conservation.

I'll disagree.

Decomposition part of the cycle of life , I agree.

Returning all carbon to the air , the definition of rotting plant matter .. not any definition of rotting , or decomposition I've seen requires this "All" part... nor do any of them require the 'to the air' part.

All the definitions I've read of rotting , decomposition , decay , etc .. all refer one way or the other .. to breaking down material to component parts .. not about requiring "all" the carbon to get back to the air.

A % of the carbon not being put back in the air by decomposition .. it instead going further down to form things like fossil fuels and such .. also equally supports laws of conservation.

[freebeard]

So which is it? Lounge or Unicorn?

[IamIan]

Originally Posted by freebeard

So which is it? Lounge or Unicorn?

Why? .. I don't follow ?

Nothing has been Unicorn ? .. It's MIT research , decomposition, etc .. none of that is Unicorn stuff.

General Efficiency of coal powered BEVs fits here in the General Efficiency section as well ??

Not even anything seriously off topic .. For example .. from the OP:

"Generating electricity in a clean and efficient manner while the CO2 can easily be captured."

Some talk has been had about parts of that .. the efficiency .. the carbon capture .. etc.

[cRiPpLe_rOoStEr]

Originally Posted by NeilBlanchard

Yes, rotting plant matter returns all the carbon to the air - by definition.

And we must not forget that the carbon returning to the air as methane has a longer half-life and a higher greenhouse effect compared to CO² from the wood burning. So, even if there is no total carbon recovery, this process is still somewhat efficient.