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Here's a good steel production flowchart that shows where this process would be used (replace the natural gas-powered direct reduction feed-in to the electric a
by photochemsyn 4y ago
Here's a good steel production flowchart that shows where this process would be used (replace the natural gas-powered direct reduction feed-in to the electric arc furnace with a hydrogen-powered direct-reduction step). Overall, it's part of the electric arc process which avoids the need for coke from coal in blast furnaces.
https://www.steel.org/steel-technology/steel-production/ https://www.steel.org/steel-technology/steel-production/
Of course, making this fossil-fuel free requires significant hydrogen production from sources like hydropower (or nuclear) powered electrolyis, or my favorite, photoelectrochemical reduction of water, such as:
https://techxplore.com/news/2017-08-decades-technology-nrel-solar-to-hydrogen.html https://techxplore.com/news/2017-08-decades-technology-nrel-...
As far as the claims about producing a superior product with hydrogen compared to natural gas, that's hard to evaluate without more data. I imagine quality of the incoming ore is a major factor. If you want a technical paper on it, here's something recent from what looks like a China-Germany research collaboration:
https://sci-hub.se/10.1016/j.actamat.2021.116933 https://sci-hub.se/10.1016/j.actamat.2021.116933
"(2021) Influence of microstructure and atomic-scale chemistry on the direct
reduction of iron ore with hydrogen at 700°C"
P.S. The issue of hydrogen embrittlement of steel doesn't apply here, although it is a major issue that doesn't bode that well for replacing natural gas with hydrogen anywhere other than in industrial processes where the hydrogen is being consumed almost as fast as it is produced. Making synthetic natural gas from atmospheric CO2 and water-sourced hydrogen is a (currently expensive) option, however.
- hinkley 4y agoMethane digesters would probably be more efficient, but I’m not sure about the volume.
- ncmncm 4y agoIt is substantially more efficient, by unit of collecting area, to produce electricity using a regular solar panel and then electrolyse water for hydrogen. But of course collection area efficiency is not what matters, cost is. We don't know what the electrophotochemical equipment costs, or how that compares. It does seem more elegant, at a remove. In practice, of course, you drive your electrolyser from solar, wind, hydro, geo, tidal, numerous forms of storage, or an unholy mix of all of them at different times -- whatever comes off the grid. At first, it will include NG sometimes, and nukes, until those are priced off of the market.
- pstuart 4y agoThe photoelectrochemical reduction of water looks interesting -- what do you think the achievable efficiency of it might be and is there an existing path to commercialize the technology? Also, would that work in a concentrated solar setup?
- panick21_ 4y agoI always found the process promoted by Boston Metal (https://www.bostonmetal.com/ https://www.bostonmetal.com/) to be more interesting. No need for a hydrogen in-between step, just electricity.
- antupis 4y agoThere is huge boom at wind power around Gulf of Bothnia, and we need to dump all that excess power somewhere so I think hydrogen would come there.