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Environmental News

Discussion in 'Environmental Discussion' started by tochatihu, Oct 22, 2015.

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  1. Trollbait

    Trollbait It's a D&D thing

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    Large scale field experiment for adjusting ocean pH to capture carbon is planned.

    Cape Cod scientists want to dump 60,000+ gallons of sodium hydroxide into ocean in climate change experiment

    Those against are ignorant or cynics using emotional messaging. Solid sodium hydroxide, NaOH, or lye is nasty stuff you don't want on you, but the project is talking about pouring in gallons. It is predissovled, so even if the starting solution is of dangerous strength, it will quickly disperse in the ocean currents.
     
    #2321 Trollbait, Jul 18, 2024 at 11:38 AM
    tochatihu likes this.
  2. tochatihu

    tochatihu Senior Member

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    Had not heard of this. WHOI plans to add 50% NaOH and that is plenty nasty. Reliable eye protection at least.

    FAQs: The LOC-NESS Project

    I see a bulk price $USD 362 per ton of 50% NaOH. Not showing my work (but I could) this means a direct cost of about $1370 per ton of CO2 sequestered. That is not a low price compared to other C seq technologies, but maybe there are other benefits such as mitigating ocean acidification.

    Making NaOH involves electrolysis, and if that electricity comes from 'burning stuff', this will not be a carbon negative process. Sounds like fun though.

    ==
    I have students play with CO2 measuring equipment and 1 molar NaOH solution. But still with eye protection :) [CO2] in lab air can be 800 ppm (with windows closed). Watching that go to zero in a matter of seconds is impressive.
     
    #2322 tochatihu, Jul 18, 2024 at 12:35 PM
  3. Trollbait

    Trollbait It's a D&D thing

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    We use a NaOH solution capture CO2 from fermentation. Have to be careful not to have the carbonate made go further to bicarb.
     
    #2323 Trollbait, Jul 18, 2024 at 2:10 PM
  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Direct carbon capture from sea or atmosphere makes no sense. At least six orders of magnitude being added not counting the carbon released by manufacturing the sodium hydroxide. Fish kill most likely outcome.

    Bob Wilson
     
    #2324 bwilson4web, Jul 18, 2024 at 6:35 PM
  5. Trollbait

    Trollbait It's a D&D thing

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    Decreasing pH from the CO2 in the water will kill the fish, other critters, and plants.

    Sodium hydroxide reacts with the carbonic acid to form sodium carbonate, and then sodium bicarbonate, which isn't as soluble in water as the rest.
     
    #2325 Trollbait, Jul 18, 2024 at 7:21 PM
  6. tochatihu

    tochatihu Senior Member

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    Just increase pH a leeeetle bit. That is a very strongly buffered aqueous system.

    Unless one obtains NaOH in a way that does not require electricity from burning, this cannot be net-C-negative. The process made me wonder if there might be a way to couple this with lithium recovery from brines. I think NaOH production could be combined with water production from ocean by reverse osmosis.

    I should put a spreadsheet here describing CO2 release from fossil fuels burning, per megawatt hour produced. Currently in draft form, it allows changes to input parameters. But the rule of thumb is about $USD 300 per ton CO2 produced. Flip that, and if any electricity based C seq process costs >$300 per ton CO2, it cannot win.
     
    #2326 tochatihu, Jul 18, 2024 at 8:46 PM
  7. Trollbait

    Trollbait It's a D&D thing

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    The US still allows the asbestos method.
    Chloralkali process - Wikipedia

    If using a carbon free electricity, it also yields green hydrogen. If you don't have another use for that, it can go to producing some energy for the system. Just need to do something with the chlorine.
     
    #2327 Trollbait, Jul 18, 2024 at 9:28 PM
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