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What's new

New power source? CO2 in. Electricity and hydrogen out.

PeteM

Diamond
Joined
Jan 15, 2002
Location
West Coast, USA
Have no idea if this scales and it could just be UNIST public relations at work. But, it is an interesting proof of concept:

Scientists turn carbon emissions into usable energy

Imagine fueling one of these with, say, coal plant emissions, scrubbing the CO2 output, and ending up with three energy sources?? One can imagine energy-intensive operations (aluminum production? cement production? server farms?) co-located with dirty power plants.

One of the interesting things, at least to me, is that a South Korean (at UNIST) was the lead investigator on this -- and even the Georgia Tech collaborators Asian.
 
The concept and idea sounds good on many levels.

1.
It seems to use existing outputs and further re-use them for extra energy. Good.

2.
It claims extremely high 50% conversion levels, in efficiency. Beyond excellent.
- This is suspect.
The best multi-stage plants running today do about 30% in efficiency - thus a 50% single stage process seems highly suspect on many levels.

Can the process scale up, to what size, with what reactors/materials/costs ?
What exotic metals are required for anodes, cathodes, leads, tanks, pumps ?

Does the process require very high voltages, pressures, pumps, storage, etc ?

3.
The article is Very Suspect because it mentions nothing about flow levels, costs, and output results.
 
LOL!

Where does the sodium come from?

Solar cells producing sodium from the hydroxide is great but there is only so much of it. Global demand for the HCL produced from the chloralkali process is only so much. Need gigatons of NaOH to decarbonate the planet.

Maybe setup NA production on mars and vent the chlorine to space?
 
LOL!

Where does the sodium come from?

That was what i thought as soon as i saw it, if making aluminum is bad, have they got any idea of the energy it takes to convert sodium into a metallic from its naturally occurring states. Unless im missing something this is just a sodium lead battery cell running on carbonic acid. Even if they can get the sodium carbonate to fall out of solution the sodium costs alone would be nuts.
 
Sodium ion battery.

Sodium is abundant- 6th most common element in the earth's crust. It's cheap to produce from NaCl which is also abundant. About .20/lb to produce on a commercial scale using electrolysis.

What I wonder about is that barrier. As I understand it, NASICON can be very reactive- and if it goes away, you have sodium and seawater, which would be an explosive combination.

I like the concept if it can be scaled.
 
...Imagine fueling one of these with, say, coal plant emissions, scrubbing the CO2 output, and ending up with three energy sources??
The more I think about it, this seems brilliant to me. I love the simplicity. They don't say anything about the sodium bicarb, but that has commercial value as well as the hydrogen.

There's no waste. Everything produced is useful, and it sequesters carbon as the process. I could imagine one of these setups on every fossil fuel power plant.
 
The concept and idea sounds good on many levels.

1.
It seems to use existing outputs and further re-use them for extra energy. Good.

2.
It claims extremely high 50% conversion levels, in efficiency. Beyond excellent.
- This is suspect.
The best multi-stage plants running today do about 30% in efficiency - thus a 50% single stage process seems highly suspect on many levels.

Can the process scale up, to what size, with what reactors/materials/costs ?
What exotic metals are required for anodes, cathodes, leads, tanks, pumps ?

Does the process require very high voltages, pressures, pumps, storage, etc ?

3.
The article is Very Suspect because it mentions nothing about flow levels, costs, and output results.
I know you don't like it because Tesla didn't make it but:
World’s Most Efficient Combined-Cycle Power Plant | GE Power
I
 
Sodium ion battery.

Sodium is abundant- 6th most common element in the earth's crust. It's cheap to produce from NaCl which is also abundant. About .20/lb to produce on a commercial scale using electrolysis.

What I wonder about is that barrier. As I understand it, NASICON can be very reactive- and if it goes away, you have sodium and seawater, which would be an explosive combination.

I like the concept if it can be scaled.

IMHO i think your numbers are off on the sodium and i don't think you need to look at cost so much as energy in in the form of refined sodium V energy out. If you are not capturing more CO2 than is generated making the electric for the constituents - consumables of this cell your not benefiting the world!
 
IMHO i think your numbers are off on the sodium
The cost I cited came from here:

ELEMENT: SODIUM

Metallic sodium is priced at about 15 to 20 cents/lb in quantity. Reagent grade (ACS) sodium in January 1990 cost about $35/lb. On a volume basis, it is the cheapest of all metals.
They say 4th most common element, other places say 6th. I erred on the side of caution and cited the lower number.

From the same link:

Sodium is present in fair abundance in the sun and stars. The D lines of sodium are among the most prominent in the solar spectrum. Sodium is the fourth most abundant element on earth, comprising about 2.6% of the earth's crust; it is the most abundant of the alkali group of metals.


...and i don't think you need to look at cost so much as energy in in the form of refined sodium V energy out. If you are not capturing more CO2 than is generated making the electric for the constituents - consumables of this cell your not benefiting the world!
I think there is a misunderstanding of the efficiency and the purpose. This is just my take- I may be wrong, but the 50% efficiency I read as the conversion of CO2 to Sodium Bicarb. Meaning half of the CO2 input will precipitate out, and half will stay in solution or gas off.

The only electrical requirement of the system would be the pumps. The energy comes from the chemical reaction, so assuming the cost to produce the sodium is correct, the sodium component cost would be low. The CO2 generated in producing the sodium should not that much, based on the cost of the sodium itself.

Admit I am engaging in some speculation there.

The beauty of this idea (to me) is that it is not about generating power. It is about sequestering CO2 in an efficient manner, and it has the happy by-product of producing useful stuff in the process. I don't really care if it is a net winner or loser wrt the power generated as long as the losses are lower than the cost of current CO2 sequestration technology.

What I like best is that it generates no waste products. The Na ions used in the conversion are essentially free, the other input (C02) is a waste product that we want to get rid of anyway.

So the calculus becomes this: Does the cost of the process, minus the revenue generated by the production of electricity, hydrogen, and sodium bicarb, exceed the cost of current CO2 sequestration technologies?

I don't know that answer- but the elegance of the design and simplicity of the process leads me to believe that is would not only be less expensive than what we do now, it could potentially turn a tidy profit.

I was a Chemistry major, so I may be biased, but I really like this idea. ;)
 
Don't get me wrong, i like the idea, but thermal power plants are only 40% efficient at best, ergo how many CO2 molecules are you making to generate the molecules of sodium to capture them. If you can not generate more fresh sodium than you can capture CO2 your not benefiting anything. Using more carbon than you can capture just to capture some is a net negative is it not?

If sodium realy is just 20 cents a pound thats great, but it has no bearing on its energy costs to recover it. I find coal price online at about 3 cents a lb, ergo on the cost theory that means each lb of sodium could take upto 6 lbs of coal to make? Can the 1lb of sodium really capture it. I don't know enough chemistry to answer, i do know enough chemistry to know splitting sodium off a salt is seriously energy intensive as is taking - breaking of the carbon from CO2. Making CO2 is seriously cheap though!

Remember carbon capture is only a benefit to mankind when it captures more carbon than the carbon generated to make the system work.
 
A mate mentioned this to me a while back, not looked into whats involved but theres boots on the floor.


Edit:- Oops, I might be a bit off topic, interesting watch anyways :D
 
A mate mentioned this to me a while back, not looked into whats involved but theres boots on the floor.


Edit:- Oops, I might be a bit off topic, interesting watch anyways :D

This all is very encouraging to see. We must find things to reduce these emissions.
 
...If sodium realy is just 20 cents a pound thats great, but it has no bearing on its energy costs to recover it.
It does if the producers want to earn a profit. Pure sodium does not occur naturally, so the cost to produce it must include the energy cost.

It's 4196 coulombs/mole, if that helps. You're also producing chlorine, so the cost is split between the commercial value of both products.

The process used today is about 100 years old. Mine the salt, heat it to molten, and run a DC current through it. The sodium floats to the top at the cathode where it's skimmed off, and the chlorine is collected as it gasses off at the anode.

...I don't know enough chemistry to answer, i do know enough chemistry to know splitting sodium off a salt is seriously energy intensive as is taking - breaking of the carbon from CO2.
Melting the salt frees up the Na+ and Cl- ions. It only takes 6V DC to get them going in the right direction. The amount you produce will be a function of the amperage.

There will be energy expended keeping the NaCl molten- they add CaCl to lower the melting point. and they over-voltage the cell to add heat and keep the Na reduction at an optimum rate (the process technically only requires 4V).

So a commercial scale Down's cell, 6V at 30K amps is 180KVA. About as much power consumption as a couple mid-sized CNC machines.

The are huge salt deposits out there- there is a mine in Poland that opened in the 13th century and produced salt continuously until 1996- they finally shut down because the price of salt was so low. So your raw material costs about the same as dirt.
 
Lol don't want to sound like a broken record, but this sounds like the old perpetual motor driving the alternator machine.

I can't find googling a answer, but im really suspicious, because if you can get enough electric out of burning the hydrocarbons (which you may be able to because of there hydrogen content) to then make the sodium to recapture that carbon this is a bad thing, but if you can get sufficiently energy positive, then yeah its a game changer in that it lets us unlock the hydrocarbons energy with minimal negatives. So long as presumably the sodium bicarbonate is not then used in a way that brakes down into CO2. Im no expert on chemistry but making bonds generally releases energy and breaking them generally consumes energy. But i do kinda get how you could break stuff down into less total bonds for a net positive energy release.

yeah not disputing salts readily available, we have massive salt mines here in the uk. Its not something the world is short of by any means and brine extraction is pretty dang simple especially once some one drills a hole in the lake above you!

Im far more skeptical about using a high grade energy in the form of electric to then capture and recombine the CO2 into a liquid fuel, the very fact the end product ends up in a sub 40% efficient combustion engine means its gotta be way less efficient than simply using the electrical energy directly even with current battery technologies. Now sure for stuff like rocket fuel on mars, that is a different set of variables were you have to have - make a liquid fuel. Here on earth, i just think the idea of the combustion engine needs to be heading in the direction of the steam engine, sure still have bespoke uses, but for every day batteries and electric motors to me make more sense.
 
Lol don't want to sound like a broken record, but this sounds like the old perpetual motor driving the alternator machine.
It's not about making a perpetual motion machine. We already capture and sequester carbon by pumping it underground. There is cost associated with that, and it's not inexpensive.

Not all chemical bonds are created equal. Ionic bonds are stronger than covalent bonds, molecules with multiple bonds are harder to break than those with single bonds, The valence state is what counts.

In all fluids, there is a constant breaking and reforming of these bonds. The process described in the OP happens naturally in the oceans. CO2 is absorbed from the atmosphere and combines with water to form carbonic acid. CO2+H2O=H2CO3. This is an equilibrium equation, which means that if the carbonic acid level is above the equilibrium point the reaction reverses and the carbonic acid breaks down to H20 and C02.

There is a continuous process of carbonate ions forming and breaking bonds with Hydrogen, and since the oceans are a highly reactive soup, the carbonate ions attach to other stuff too- Flourine, Sodium, Calcium, etc. Some of these carbonate ions are used by marine life to form calcium carbonate (shells), some of it bonds naturally into various salts. Eventually it precipitates out (ex. limestone is CaCO3). The oceans are super-saturated with carbonates, which means that absent the other elements that are also attracted to carbonates, they would precipitate out at a much higher rate.

This idea just accelerates that process, and takes advantage of the inherent affinities in the system to make baking soda and hydrogen gas. That is the beauty of the idea. It doesn't have to be a perpetual motion machine- it only has to be cheaper than capturing CO2 at the source, transporting it to some distant place, and pumping it underground and hoping it stays there forever.

The chemistry is old school- the enabler is the Nasicon material which passes the electrical potential between the anode and cathode, and allows the transport of the Na ions while preventing the water from contaminating the sodium side.
 
So the CO2 is sequestered as baking soda solution. wonder what they do with that? Current world production of Na carb/bicarb is in the 50M ton
range, best I can tell from google, it may be less. There is no shortage of these. The battery produces electricity while generating hydrogen and consuming Na metal. If I read the chemistry correctly, an ideal cell will generate about 5kw-hrs of electricity per kg of Na consumed while sequestering just short of 2kg of CO2. I gather the Na metal must be molten for the cell to work (MP~208F). From this the electricity production is a side show to the CO2 sequestration when you consider how Na metal is made electrolytically.

Perhaps someone has some insight into this but it looks like an expensive way to sequester CO2 with Na metal at $0.44/kg. So sequestration of CO2
is $0.22/kg or $220 per metric ton. Talk about a carbon tax.... FWIW France taxes carbon at the equivalent of $300/ton when sold as motor fuel.
 
I seriously doubt sodium is still available at 20 cents a pound. If that were the case chlorine should be 20 cents a pound as well neglecting the cost to liquify and ship it. Since there is no industrial need for millions-billions of tons of chlorine, the choralkili process woud need to be used so that the HCL produced could be dumped into the environment as there would be no use for it either at the volumes generated. Problem is dumping the hcl is going to react with carbonates in the ground and release co2 and generate more salt.


Anyhow, still need carbon free electricity to generate sodium to soak up carbon.


Why not just use the carbon free electricity to displace the coal, oil and natural gas fed electrical generation in the first place.
 
...Since there is no industrial need for millions-billions of tons of chlorine, the choralkili process woud need to be used so that the HCL produced could be dumped into the environment as there would be no use for it either at the volumes generated. Problem is dumping the hcl is going to react with carbonates in the ground and release co2 and generate more salt.

...

Why not just use the carbon free electricity to displace the coal, oil and natural gas fed electrical generation in the first place.
Lots of assumptions there. Chlorine is an important feedstock in the production of PVC and Polyurethanes. World production of Chlorine via electrolysis of brine was 65 million tons in 2016. US production was 14 million tons.

CO2 emissions from coal in the US is 1.2 million tons a year according to the EIA. If you can half that, that would be good, yes?

There is no reason to produce HCl. It's not a product of the sodium production, and there would be no need to dispose of the chlorine that way. Just reduce the amount of chlorine produced by the current methods.

The only carbon free power that is baseload power is nuclear, and to a much lesser extent geothermal. If you build a lot of wind and solar farms, you need storage, which will very possibly use sodium ion batteries.
 








 
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