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Total agreement. Although zirconium and tungsten aren't exactly the most expensive metals, they are extremely hard and dense and processing them in this manner

Total agreement. Although zirconium and tungsten aren't exactly the most expensive metals, they are extremely hard and dense and processing them in this manner would appear to be a big minus against this technology. I can picture a factory warehouse putting out 40' containers of PV's, racking, and backup batteries daily, while a far more massive smelter and mill next door struggles to manufacture the equivalent for CPV. I'm glad they addressed the thermolysis of CO2, because that was a major concern. Having explored thermolysis as a method for reversing carbon dioxide buildup in Earth's air, I realized quickly that breaking CO2 down into CO is not challenging at all, but getting the CO to go to C is the highest temperature reaction known. Just because I don't think this breakthrough is going to win doesn't mean I'm not thrilled they made it. Never know what other breakthroughs may leverage this technology.

ars 8y ago
> but getting the CO to go to C is the highest temperature reaction known. Even higher than H2 + O ? (I'm sure it's not higher than H + H, but that one probably doesn't count.) And won't atomic carbon react with other carbon? So you don't actually need to supply as much energy as it may appear.
- vondur 8y ago
  I’d imagine the thermodynamics are not favorable for the reduction of CO to elemental carbon. Burning H2 in oxygen is very thermodynamically favored.
  - ars 8y ago
    Obviously I meant thermolysis of water when I wrote that. It only takes place at extremely high temperatures, and I'd like to see data that carbon monoxide is at a higher temperature.
- mchannon 8y ago
  From chapter 211 of my book: None have proposed then taking the CO through a final step and ending up with simple C and O. This is not without good reason: out of all substances known to thermally decompose, none does it at a higher temperature than carbon monoxide. If you thought 2,000° was hard, try 3,870° C. That’s hot enough to melt any known metal. That’s hot enough to melt any rock! The few substances known to man that can be counted on to stay solid at that temperature can be counted on one hand.
  - philipkglass 8y ago
    I tried searching for that excerpt from your book and couldn't find any matches. Is the book published? I'd be interested in reading it. If I wanted to turn carbon dioxide back into elemental carbon I'd probably try to get there via the Bosch reaction with electrolytic hydrogen: https://en.wikipedia.org/wiki/Bosch_reaction https://en.wikipedia.org/wiki/Bosch_reaction NASA has funded a fair bit of lab scale work on it for recycling breathable atmosphere on space stations. It doesn't require heroic super-materials. You can theoretically store the input CO2 and H2 in large buffers so as to smooth out intermittently available input energy, without needing to firm up the primary energy supply itself.
    - mchannon 8y ago
      The full book is not yet available anywhere. It's self-published (and I mean that literally; I'm doing the printing and binding myself, to discourage making it another $.99 Kindle throwaway or having a crappy low-res PDF version of it floating on torrents or sci-hub). List price on it will be in the hundreds of dollars. I'm not trying to sell as many copies as cheaply as possible, which might be hard for some people to understand. Message me your info and I'll give you a discount on price. Elemental carbon is probably the wrong goal: keeping a limited pool of CO2 and thermally converting it to CO, then water-shifting the CO into CO2 + H2 is far more practical. If you want to bury the carbon, it's more practical to bury it as a hydrocarbon, which is easily accomplished with the CO + H2 used through Fischer-Tropsch. If you want to convert the carbon back into food, there's probably some clever process to convert F-T product oil into sugars and carbohydrates.
      - philipkglass 8y ago
        Yes, I am interested, though I'm not sure what your book is about in general. I just emailed you from an .edu address. What is the goal you're aiming at? Carbon-neutral synthetic fuels? From the excerpt, I thought you might be considering converting atmospheric CO2 back into relatively low-reactivity, compact, reduced forms of carbon for burial in e.g. old coal mines. (Which would be astonishingly energy intensive, but I wouldn't put it past the capabilities of early-22nd-century civilization if automation continues to advance and we avoid nuclear war, super-pandemics, and other such disasters.)

ars 8y ago

> but getting the CO to go to C is the highest temperature reaction known. Even higher than H2 + O ? (I'm sure it's not higher than H + H, but that one probably doesn't count.) And won't atomic carbon react with other carbon? So you don't actually need to supply as much energy as it may appear.

vondur 8y ago
I’d imagine the thermodynamics are not favorable for the reduction of CO to elemental carbon. Burning H2 in oxygen is very thermodynamically favored.
- ars 8y ago
  Obviously I meant thermolysis of water when I wrote that. It only takes place at extremely high temperatures, and I'd like to see data that carbon monoxide is at a higher temperature.
mchannon 8y ago
From chapter 211 of my book: None have proposed then taking the CO through a final step and ending up with simple C and O. This is not without good reason: out of all substances known to thermally decompose, none does it at a higher temperature than carbon monoxide. If you thought 2,000° was hard, try 3,870° C. That’s hot enough to melt any known metal. That’s hot enough to melt any rock! The few substances known to man that can be counted on to stay solid at that temperature can be counted on one hand.
- philipkglass 8y ago
  I tried searching for that excerpt from your book and couldn't find any matches. Is the book published? I'd be interested in reading it. If I wanted to turn carbon dioxide back into elemental carbon I'd probably try to get there via the Bosch reaction with electrolytic hydrogen: https://en.wikipedia.org/wiki/Bosch_reaction https://en.wikipedia.org/wiki/Bosch_reaction NASA has funded a fair bit of lab scale work on it for recycling breathable atmosphere on space stations. It doesn't require heroic super-materials. You can theoretically store the input CO2 and H2 in large buffers so as to smooth out intermittently available input energy, without needing to firm up the primary energy supply itself.
  - mchannon 8y ago
    The full book is not yet available anywhere. It's self-published (and I mean that literally; I'm doing the printing and binding myself, to discourage making it another $.99 Kindle throwaway or having a crappy low-res PDF version of it floating on torrents or sci-hub). List price on it will be in the hundreds of dollars. I'm not trying to sell as many copies as cheaply as possible, which might be hard for some people to understand. Message me your info and I'll give you a discount on price. Elemental carbon is probably the wrong goal: keeping a limited pool of CO2 and thermally converting it to CO, then water-shifting the CO into CO2 + H2 is far more practical. If you want to bury the carbon, it's more practical to bury it as a hydrocarbon, which is easily accomplished with the CO + H2 used through Fischer-Tropsch. If you want to convert the carbon back into food, there's probably some clever process to convert F-T product oil into sugars and carbohydrates.
    - philipkglass 8y ago
      Yes, I am interested, though I'm not sure what your book is about in general. I just emailed you from an .edu address. What is the goal you're aiming at? Carbon-neutral synthetic fuels? From the excerpt, I thought you might be considering converting atmospheric CO2 back into relatively low-reactivity, compact, reduced forms of carbon for burial in e.g. old coal mines. (Which would be astonishingly energy intensive, but I wouldn't put it past the capabilities of early-22nd-century civilization if automation continues to advance and we avoid nuclear war, super-pandemics, and other such disasters.)