CO2 capture

As far as I can tell, CO2 capture remains largely irrelevant to decarbonizing the electric grid over the next 30 years. It might find a place here and there under highly specific local circumstances but it isn't likely to be play a significant role nationwide overall.

 

I don't follow. Low carbon energy is an indistinct benefit?

I think it is better to treat that 15% loss as an inherent cost of coal use. Charge it either to the customer buying the captured CO2, or accept it as a necessary cost of using that particular energy source. And if that boosted cost makes coal non-competitive, then so be it. Let it die.

Why does the raw energy cost of collection matter? Ignore the gross output. Focus instead on the dollar cost of the net energy output, after the extraction and emission problems are cleaned up and safely put away.

I've heard of other combustion methods that might work better. Instead of burning the fuel in a normal nitrogen-rich atmosphere, burn it instead in a closed system with pure (or highly enriched) oxygen. The primary exhaust would then be CO2, unlike current flue gas that is more nitrogen than anything else. This gives a big jumpstart on separating the CO2 from the other stuff. For oil and gas, the exhaust would be mainly equal parts CO2 and H2O, still an easier starting point than 80% N2.

There should be other possibilities too.

 

CO2 capture can be commercially successful for certain cleaner technology processing options such as coal gasification and probably burning of natural gas. As far as traditional coal fired power plants, I would be less optimistic.

 

I suspect that doing it right will not involve using most of the existing traditional plants.

 

I resurrect this thread to post:

https://www.heirloomcarbon.com/news/heirloom-and-microsoft-sign-permanent-co2-removal-deal

Recently put US govt investment in carbon capture in environmental news thread, but we might do better separating it.

Heirloom starts with limestone calcium carbonate. Heating it expels CO2 and makes (calcium oxide and then) calcium hydroxide. That calcium hydroxide can absorb CO2 from combustion flue gas (etc.) to make limestone again. So it is a net nothing, right?

Not quite. Trick here is that limestone oven produces CO2 at high concentration that can be injected int deep basalt (etc.) or mixed with concrete, or used in other ways. The calcium hydroxide will absorb CO2 from low concentrations (even as low as air).

So the real net effect is that by baking (adding energy to) limestone, you can concentrate CO2 (which is useful) from low-concentration source gases containing CO2. Energy -> negentropy.

It is important to know how much energy is required to bake limestone, and whether that input has its own CO2 emissions. Heirloom claims they can do this 'at scale' for USD$100 per ton CO2 ($370 per ton carbon) net trapped. Microsoft's investment of megamillions indicates that they believe it.

Many other chemistries reversibly trap CO2 including some that are very complicated and so, get into whiz bang journals. But limestone is cheaper than dirt (technically speaking). If it's not exactly where you want to build your carbon-capture plant (which is a pun if you think about it), you probably don't need to drive your trucks very far to bring back megatons. Distance matters because those trucks don't run on sunshine (not directly ).

 

I sometimes need to restock on lime to put on walls or between bricks.

I had the impression that the suppliers have been mining a few big deposits in a few identified places.

But then, maybe that's because those deposits have lime of good quality for making walls.

The suppliers also contend over whether I'd really rather have dolomitic or calcitic lime for my walls. Their recommendations seem to reflect what is in the deposits they are mining.

It might be cheaper than dirt somewhere, but getting my hands on a bag of it takes more doing than getting a bag of dirt.

 

The practice of burning coal may be running into economic problems. It is very hard to meet Coal burning air discharge regulations these days - and- it is becoming apparent Coal is much too valuable a resource for industry to be burning.

However Coal is an abundant energy source in many areas of the world that has been used by industry since the Industrial Age and even before that. Its hold on economies is tenacious and not easily broken.

 

Calcium hydroxide almost gave me a bad day.

Was going through chemical inventory in the lab, and there was a largish bottle of it, maybe a kilo, on the top shelf. A plastic one that starts cracking with age. It looked fine, but when I gave it a slight squeeze to test the pliability, the bottle simply burst. Lucky me, the bottle was almost empty, and the bottom of the bottle holding the remaining hydroxide stayed intact and in my hand. Ended up with just a dusting on my arms and shirt, instead of in my face and all over the bench.

Staying on subject, we've done some work using sodium hydroxide for CO2 capture of ethanol fermentations. Might try the calcium hydroxide.

 

Apparently, if I really wanted to do walls the ol'-fashioned way, I'd be buying CaO and slaking it in water on site (stand back, dramatically exothermic) to get the Ca(OH)₂. My taste may not run to that much drama (I'm told that CaO stuff can really give you a bad day), so I've been leaving the drama to others and buying pre-slaked Ca(OH)₂.

Still quite alkaline and unrecommended for skin and eyes, but has never bothered me much if I got a little inadvertently on skin.

There was another thread here not long ago about recent findings that Romans were making concrete by tossing straight CaO right into the mix (and, presumably, standing back).

 

As the Aliso Canyon leak goes to show injecting a gas underground isn’t really captured .

even deep hard rock storage is like a leaky balloon.

If it takes 15% more energy to pump it down that 15% is just going to be 15% more pollution. It will eventually come back out, even if it takes an earthquake in a thousand years.

Oddly enough diffusion of exhaust through soil (not deep) or even a body of water can be done at extremely low pressure if the surface area is large.

As that one French farmer discovered exhaust mixed in soil accelerates growth in that soil including microbes and the overall pollution emitted as the gas works its way back into the atmosphere can be reduced to zero or much lower than expected.

Plant your gigantic plants next to forest or grassy fields and if you diffuse through underground permeable pipes you might actually sequester a lot of it in the form of accelerated microbe and vegetation growth.

It was found even desert soils lock in a lot of the pollution

 

What about the basalt injection test projects, ongoing in Iceland and also tested in Columbia River basalts in my state at Wallula? I've understood that these found the injected CO2 being turned into solid carbonate minerals very quickly, even on human time scales, not just geologic time:

https://eos.org/articles/basalts-turn-carbon-into-stone-for-permanent-storage
Wallula Basalt Project | PNNL

 

Methane and CO2 aren't the same. That leak may have happened due to damage caused when removing the gas from the formation.
https://en.wikipedia.org/wiki/Aliso_Canyon_gas_leak

Many of the formations being chosen for CO2 sequestering were picked for the chemical reactions that will take place there to convert it into a solid.

Then on the other side, a lot of current CO2 sequestering being counted in the US is just CO2 injecting into oil wells to increase production.

CO2 fertilization has been used in some fields(not just the farm type) for some time. I wouldn't exactly call it sequestering. Where it is being injected is an active part of the biosphere. The organisms consuming it will eventually be eaten in turn, with the eventual release of that carbon into the air. It is a delaying mechanism. If starting with fossil fuels, and I've seen greenhouse systems that literally burned propane, it is still a net increase of CO2 in the atmosphere.

Getting more use out of the CO2 exhaust is still worthwhile than just dumping it into the air. Just saying we shouldn't call this a long term solution. Same as with soda water. Much of the CO2 for that comes from the hydrogen production from methane.

 

"What about the basalt injection test projects"

They work fast, has been demonstrated by retrieved rock cores containing the desired end-product mineral. The CO2 is sent down at high concentrations. Basalt 'down there' is rather warm. So, fast.

==
Aliso Canyon leak. @Trollbait (CaO survivor) correctly states this it was purely capped rock storage, not sequestration by chemical reaction.

But we should not say "was" because Aliso Canyon CH4 storage was recently approved for expansion:
California to allow more fossil gas storage at Aliso Canyon

==
"Plant your gigantic plants next to forest or grassy fields and if you diffuse through underground permeable pipes"
Not liking this idea. Trenching and installing underground permeable pipes would be expensive, IS damaging to root and soil processes, and I don't even know how to count CO2 trap success afterwards. Actually I do. Requires paired experiments to trench and install (unused) pipes in other areas and measure later CO2 soil-surface fluxes there. Very big and hard to assess project.

Alternative: inject CO2 into septic tank leach fields. They are many and present in many biological settings. Measure CO2 soil-surface fluxes for a while before injection starts. (Could publish that standalone, because CO2 efflux from leach fields have not been examined to my knowledge). Then inject CO2 and do mass balance on altered efflux. Giving half a point here for having stimulating thinking about it.

 

"What about the basalt injection test projects"

They work fast, has been demonstrated by retrieved rock cores containing the desired end-product mineral. The CO2 is sent down at high concentrations. Basalt 'down there' is rather warm. So, fast.

==
Aliso Canyon leak. @Trollbait (CaO survivor) correctly states this it was purely capped rock storage, not sequestration by chemical reaction.

But we should not say "was" because Aliso Canyon CH4 storage was recently approved for expansion:
California to allow more fossil gas storage at Aliso Canyon

==
"Plant your gigantic plants next to forest or grassy fields and if you diffuse through underground permeable pipes"
Not liking this idea. Trenching and installing underground permeable pipes would be expensive, IS damaging to root and soil processes, and I don't even know how to count CO2 trap success afterwards. Actually I do. Requires paired experiments to trench and install (unused) pipes in other areas and measure later CO2 soil-surface fluxes there. Very big and hard to assess project.

Alternative: inject CO2 into septic tank leach fields. They are many and present in many biological settings. Measure CO2 soil-surface fluxes for a while before injection starts. (Could publish that standalone, because CO2 efflux from leach fields have not been examined to my knowledge). Then inject CO2 and do mass balance on altered efflux. Giving half a point here for having stimulating thinking about it.

 

You can say that again!

 

A couple comments
Basalt storage is treated as being unlimited and converting basalt is also wasting a resource , this is what a 10 year solution before you get diminishing returns?

The vast majority of claimed co2 is used for injection to extract fossil fuels which is all well and good but is not really “sequestered “ either.

We are pretending we only do one thing for “co2 storage” which is inaccurate

The French have decades of doing strange things, a large compost pile as an example makes more heat (over unity) than burning the same materials.

Sending home or tractor exhaust through the soil accelerates growth which removes some waste byproducts , it’s one of those situations where 1% of the energy spent is required to push 1psi through a diffusion bed which could be coupled with a Geo-thermal element so you can store and recover heat.

As an example that has been used 70 years
100T diesel ore carts are still used underground with a water wash to protect operators.

Water washed diesel exhaust is clean with only co2 and water emitted. And some of the co2 remains in the water (what percentage depends on how long and how spent the operator allowed it to become before refilling)

Once CO2 and other pollutants are entrapped by moisture, living microorganisms and minerals in the soil this can be extracted for use by other living things.

The key is how much and how quickly would a particular soil become saturated?

The solution for pollution is dillusion, the rate of growth in soil dox’d in this fashion can be double normal rates, this increased efficiency and in theory less (or ideally no) highly energy intensive fertilizer would be required.

There was an experimental net zero algae farm at a college power plant that ran decades demonstrating the concept but for the purposes of making bio-diesel, alcohol and food supplements off a coal plants waste outputs.

All variations on the same theme of supercharging wildlife to clean some of our mess.

 

That is a much lower figure than I am seeing elsewhere.

 

2000 years but less than 1% is reasonably accessible
you can draw your own conclusions about extremely deep wells 50-200 miles offshore.