Was reading this article on CNN and was wondering what the Straightdope is on this technique. Is it viable? Could it scale up? How much would it help?
-XT
Sure, until someone accidentally mixes with vinegar. Than all of Earth becomes one huge volcano.
More seriously, you’d have to store the baking soda well away from any possible acid contamination or the CO[sub]2[/sub] gleefully escapes, defeating the purpose.
But other than that it would work and scale up? How much CO2 would we be able to take out of the atmosphere if all or most of our coal fired plants used this technique? What would it cost (probably won’t be able to answer this one, I realize)?
-XT
Skyonic Corporation developed the SkyMine™ process, and describes it thusly:
So, they’re probably making NaOH with the Chloralkali process, and bubbling the flue gases through the resulting NaOH solution.
Making NaOH isn’t free, nor is washing the sort of gas volume that a power plant puts out; but if they say it works…
They claim the process is internationally patented, but I’m not finding any ref to Skyonic in the US patent database. Maybe they mean it has an international patent, but not a US patent.
In general though, wouldn’t this be fundamentally easier than sequestering the CO[sub]2[/sub] as a liquid/gas?
And here I thought you were going to say the earth is just a giant refrigerator, so let’s open a giant box of baking soda to put in it.
Sure, but as solids go, baking soda is quite fluffy and delicate. I suppose you could mix it with lime to make it water-insoluble (similar to the manufacturing of soda-lime glass) and compress it into high-impact bricks, but the more energy you have to use to get into this relatively stable state, the less desirable the whole process becomes.
IANAScientist, but here’s a former chemistry student’s take on it…
You’ve got to get your cation from somewhere. It looks like their process uses NaCl. So for every two moles of sodium bicarbonate (NaHCO[sub]3[/sub]) you produce, you produce one mole of chlorine gas (Cl[sub]2[/sub]). If you’re talking about sequestering enough carbon to make a serious dent, you’re talking about producing a lot of chlroine. Only so much of that can be used for industrial applications, and you’ll quickly run into the problem of what to do with all this chlorine. IIRC, it’s not a good-for-the-environment chemical, so now you’ve got a new problem with a not-fun chemical.
I suppose that this method will work to sequester CO2 if it means that we no longer produce Baking Soda (NaHCO3) via other means.
If this company is able to produce baking soda from the smoke stacks, great, but… when the baking soda gets used, it releases the CO2 back into the atmosphere. Using NaHCO3 to make, say, breads, you’re using the (delayed) reaction of producing CO2 to lift the bread (give it bubbles). The gas will get into the atmosphere at some point. It’s only really sequestering CO2 if this new process displaces another means of NaHCO3 production that was not also removing CO2 from the air.
I haven’t done any direct thinking on this issue, but my guess is that chlorine is such a high energy compound that there is a good way do reduce it to chloride while producing energy without producing greenhouse gasses. If there were a real excess of chlorine being generated, I have no doubt it would find a use.
Another thing to think about: doesn’t most food-grad baking soda get used for baking than for cleaning/deodorizing? And when it’s used for baking, it undergoes a chemical reaction to make…
Carbon-dioxide! Makes the whole process kinda pointless, doesn’t it?
I think, they are talking about depositing the baking soda in the ground for sequestration, rather than baking world record sized pancakes.
But why bother to call it “food grade baking soda” rather than just plain old “bicarbonate of soda”?
Imagine if they put the factory in Jersey!
PR lingo: it conveys “harmless” to the non-scientist.
This is all very well, but sodium hydrogen carbonate is going to be a nuisance to store, what with solubility and the propensity to release some of its CO[sub]2[/sub] on heating. It would be better if we could come up with some insoluble precipitate instead. Maybe if we bioengineered some kind of marine organism to produce calcium carbonate?
While we’re getting out the mad science props, can I make a request? If we’re going to be making frankencritters, can I ask that they be tasty frankencritters? Good for soups, or something…
Yes, you could (purely hypothetically, of course) have a chemical plant that makes many metric tons of NaOH and is also one of the leading suppliers of, say, cal hypo, HCl, and a smattering of other chlorinated derivatives. I could imagine such a thing easily.
My problem with the proposed “solution” is the energy expenditure inherent in the whole scheme. I think it would be better to have some sort of solar powered carbon sink. Perhaps something that is attractive enough to be stored out in the open, say in the middle of a forest. Something vertically alligned, to maximize storage space. It could even be used as a sort of wildlife habitat and be self sustaining. . .
The sodium hydroxide and chlorine have always been co-products generated by the chloralkali process. You could certainly use the NaOH produced to absorb carbon dioxide. The trouble is, that at least right now, the cost of NaOH has gone crazy. The reduction in chlorine usage by the pulp and paper industry has driven down the supply of NaOH, because if you can’t sell the Cl2 to make a profit, you have trouble making a living on the NaOH alone. In fact, the demand for Cl2 is what drives the price of NaOH, the price of NaOH is pretty inelastic as regards to demand.
I don’t know if the current market demand for chlorine is going to support the large scale implementation of this process. In this I think it’s like a lot of environmental remediation schemes. For the first people to use offsets to eliminate their carbon footprint it’s pretty easy. As more and more people do it, the offsets are harder and harder to produce, and more expensive to buy. There’s a limit to how much land we can use for growing trees, and what do you do with the trees when they’ve grown?
Stack them in the storage space you were going to use for giant baking soda bricks.
While I’m not proposing building new forests, I think stopping massive deforestation would be a good start. But, you argue, those areas are being cleared to provide more farmland. Then we need better farming practices. Oh, but those “better” farming practices use genetially modifed plants and hazardous chemical fertilizers and pesticies.