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If you happen to have an article of converting sea water to methane, please post. My searches bring back methane dissolved in sea water and I'm curious where th

by abirch 4y ago

If you happen to have an article of converting sea water to methane, please post. My searches bring back methane dissolved in sea water and I'm curious where the carbon originates.

gpcr1949 4y ago
i think parent refers to the sabatier process, so the source of carbon is concentrated CO2 externally provided, not from seawater
hannob 4y ago
You're converting Sea water to water (desalination) and then do electrolysis to get H2. You need to get CO2 from somewhere, you can use Direct Air Capture technology to get it from the air. Then you do this: https://en.wikipedia.org/wiki/Sabatier_reaction https://en.wikipedia.org/wiki/Sabatier_reaction This is all known technology, the problem is it's not very efficient. Ultimately the discussion in climate tech circles these days is usually that most people think you'll rarely ever do this. Whenever you can you'll use something more direct, like using Hydrogen directly as an energy carrier.
- dr_dshiv 4y ago
  I love promoting the fact that RF (13.56 MHz) can directly electrolyze saltwater without electrodes (and without desalination). The process was discovered by an amateur radio technician and it was treated like pseudoscience because of breathless local news coverage that made it sound like it was a fuel source. The YouTube video (“burning saltwater”) is a classic—but there still isn’t a proper study on the efficiency of the process. (The radio technician, John Kanzius, died of cancer). https://youtu.be/Tf4gOS8aoFk https://youtu.be/Tf4gOS8aoFk Edit: here is a scientific paper characterizing the process, which is pretty interesting. No calculation of efficiency, however. https://iopscience.iop.org/article/10.1088/0963-0252/22/1/015010/meta?casa_token=EfNq4b4UMIsAAAAA:Sdsa3oBsFnR8sIGqTwVM5ejRqm_wziykIAGivV4-wN6hxMHvqoMZgJC2-TTmN5VHYW5Sj_0E4A https://iopscience.iop.org/article/10.1088/0963-0252/22/1/01...
  - techdragon 4y ago
    While he may not have gotten it more widely studied to evaluate the efficiency… did he publish more information about his process? Or did his methodology die with him?
    - dr_dshiv 4y ago
      Well, the method is shown in the video. Put a test tube of saltwater in front of an 13.56 MHz RF generator (radio antenna) and light ‘er up. The paper I posted uses a focused beam of RF and more deliberate lab methodology. But with just 5 citations, I feel like there might be a missed opportunity.
      - techdragon 4y ago
        Thanks for posting the paper! With anything RF related it can be a complete shot in the dark for anyone trying to reproduce the work without things like the frequency involved. I mean sure you could do some physics, pick a range of likely frequencies and scan around but then your at the mercy of how much power you can generate at tuneable frequencies and still relying on a bit of guesswork. Even if it’s not efficient this is a great RF science demo so it’s good to spread the knowledge around. Thanks again for posting it.
        adrian_b 4y ago
        It is unlikely that the exact value of the frequency has any importance. They have used 13.56 MHz just because it is one of the frequencies for which it is easy to find high power industrial generators, which are used e.g. for induction heating.
      - dr_dshiv 4y ago
        Here’s a mildly optimistic future vision for large-scale hydrogen production: * We build arrays of underwater resonating tubes (~ 17 m for 13.58 MHz) that optimize the RF process efficiency for generating hydrogen. * Out in the open ocean, it’s powered by floating gigawatt solarpads. * “Blossoms” of enormous mylar cells are continuously filled up with hydrogen. * The mylar hydrogen cells are plucked and transported for further processing via drone zeppelins.

by abirch 4y ago

If you happen to have an article of converting sea water to methane, please post. My searches bring back methane dissolved in sea water and I'm curious where the carbon originates.

gpcr1949 4y ago

i think parent refers to the sabatier process, so the source of carbon is concentrated CO2 externally provided, not from seawater

hannob 4y ago

You're converting Sea water to water (desalination) and then do electrolysis to get H2. You need to get CO2 from somewhere, you can use Direct Air Capture technology to get it from the air. Then you do this: https://en.wikipedia.org/wiki/Sabatier_reaction https://en.wikipedia.org/wiki/Sabatier_reaction This is all known technology, the problem is it's not very efficient. Ultimately the discussion in climate tech circles these days is usually that most people think you'll rarely ever do this. Whenever you can you'll use something more direct, like using Hydrogen directly as an energy carrier.

dr_dshiv 4y ago
I love promoting the fact that RF (13.56 MHz) can directly electrolyze saltwater without electrodes (and without desalination). The process was discovered by an amateur radio technician and it was treated like pseudoscience because of breathless local news coverage that made it sound like it was a fuel source. The YouTube video (“burning saltwater”) is a classic—but there still isn’t a proper study on the efficiency of the process. (The radio technician, John Kanzius, died of cancer). https://youtu.be/Tf4gOS8aoFk https://youtu.be/Tf4gOS8aoFk Edit: here is a scientific paper characterizing the process, which is pretty interesting. No calculation of efficiency, however. https://iopscience.iop.org/article/10.1088/0963-0252/22/1/015010/meta?casa_token=EfNq4b4UMIsAAAAA:Sdsa3oBsFnR8sIGqTwVM5ejRqm_wziykIAGivV4-wN6hxMHvqoMZgJC2-TTmN5VHYW5Sj_0E4A https://iopscience.iop.org/article/10.1088/0963-0252/22/1/01...
- techdragon 4y ago
  While he may not have gotten it more widely studied to evaluate the efficiency… did he publish more information about his process? Or did his methodology die with him?
  - dr_dshiv 4y ago
    Well, the method is shown in the video. Put a test tube of saltwater in front of an 13.56 MHz RF generator (radio antenna) and light ‘er up. The paper I posted uses a focused beam of RF and more deliberate lab methodology. But with just 5 citations, I feel like there might be a missed opportunity.
    - techdragon 4y ago
      Thanks for posting the paper! With anything RF related it can be a complete shot in the dark for anyone trying to reproduce the work without things like the frequency involved. I mean sure you could do some physics, pick a range of likely frequencies and scan around but then your at the mercy of how much power you can generate at tuneable frequencies and still relying on a bit of guesswork. Even if it’s not efficient this is a great RF science demo so it’s good to spread the knowledge around. Thanks again for posting it.
      - adrian_b 4y ago
        It is unlikely that the exact value of the frequency has any importance. They have used 13.56 MHz just because it is one of the frequencies for which it is easy to find high power industrial generators, which are used e.g. for induction heating.
    - dr_dshiv 4y ago
      Here’s a mildly optimistic future vision for large-scale hydrogen production: * We build arrays of underwater resonating tubes (~ 17 m for 13.58 MHz) that optimize the RF process efficiency for generating hydrogen. * Out in the open ocean, it’s powered by floating gigawatt solarpads. * “Blossoms” of enormous mylar cells are continuously filled up with hydrogen. * The mylar hydrogen cells are plucked and transported for further processing via drone zeppelins.