Wow, I have genuinely never heard of coked coal[1] before in my life, and was extremely confused about why a soft drink was involved in the production of steel... I guess you learn new stuff every day.
* Koks: Coke as in coal but also Cocaine as in drug.
* Kohle: Coal but also Money.
The song reflects on the situation after WW2 where people were freezing in the winter and longed for warmth but had no money to pay. This is contrasted with the party generation of the 90s.
Only when mandated by smokeless fuel laws usually, coke is less energy dense than regular (anthrocite/bitumous) coal, but more than charcoal, so using it as a household fuel means you need more storage, and spend more time refueling the fire.
This is one of many creative ways of getting rid of direct fossil fuel use in industry and in the economy overall. We need ways to make steel, cement, and fertilizer with alternative processes that do not contribute to greenhouse gas emissions, and techniques like these are extremely useful. They will make a transition away from fossil fuels possible. But all these processes require heat and electricity. The root energy source used to do all these things needs to decarbonized. That's the really big challenge.
Interesting though how if you suppose abundant, low cost renewable energy available at scale exists, the above problems suddenly become tractable and solved.
Unfortunately not and that is one of the main issues. Even if we had limitless carbon-free energy there would still be significant carbon outputs directly from the production process. The article shows one possible way of reducing this for steel, but cement is currently a different ballgame and is a substantial emissions source from its non-energy inputs.
Well with cheap carbon free electricity, we could cut all the CO2 emissions from iron and steel with hydrogen based reduction and about half that of cement manufacture (about half the carbon use is energy cost for heating as per Wikipedia article). Together about 15% of global emissions could be eliminated which is nothing to sneeze at.
In fact many intractable problems in the world can be solved by more clean electricity - eg. 8000 odd skyscraper farms are enough to feed the world eliminating farm-land requirements but would require enormous amount of energy to run - also would represent single points if failure to attack in war - so will need society to evolve
I think there is a hydraulic magnesium silicate hydrate cement that can be made from seawater-derived magnesium without carbon emissions if electricity is cheap enough. These aren't trivial engineering challenges, but they are probably solvable.
I found the Boston Metal link particularly interesting. If you consider it, combined with a small form factor nuclear reactor, you could build an iron ingot producing plant right on top of the deposits in places that would otherwise be forced to ship ore out for external processing.
They're both interesting, but the aqueous approach has some advantages. Keeping materials working at extreme temperature is difficult: basically anything above 1000C gets very hard. And a low temperature approach has the potential very big advantage of being highly dispatchable, since it would not have to be kept running to keep from freezing up. Dispatchable electrochemistry is like half a battery, just great for dealing with intermittent power sources like renewables.
The second link is interesting. I've only seen the paper on the old Norwegian pilot plant before that slide show. The Norwegians were dealing with Iron Sulfide waste from copper mining as the feed stock. Being able to directly reduce solid iron oxide is probably better.
I have also wondered if you could use the iron rich gangue from bauxite mining as a feed source.
There is a paper by a member of a Norwegian research group that ran a pilot plant in the 1950's using iron sulfide as a starting material. I think their efficiency was ~4kwh/kg. On a straight balance sheet it's not competitive against unexternalized fossil fuel based processes. It has the same problem I mentioned with hydrogen reduction. If you're using fossil fuels to create electricity to reduce iron, you can skip that generate electricity step and use the fossil fuel directly. Which is why there has been very little work in this area.
In a world where you have electricity from wind and solar with regular oversupply. And high taxes on carbon based fuels. then I think electrowinning is viable.
Fun fact, since you mentioned Norway -- in the early 1900s, Norwegian industry also used the Birkeland-Eyde process to produce nitric acid for fertilizer from atmospheric nitrogen.
The process is not energy-competitive with other processes, but since the plants in question had very cheap hydropower energy that couldn't be exported for use elsewhere, this was not a dealbreaker.
I'm thinking that energy-intensive industry in early hydropower-friendly regions could get away with using simple but inefficient processes, since the energy couldn't be used for anything better anyway. Sort of like creating a minimum viable product of an industrial process, before optimizing and getting great efficiency increases.
The paper I saw was doing it using an aqueous process at ordinary temperatures. Capital costs of the actual cells would likely be very low. Though feed stock processing might not be.
One of things that struck me is if the capital costs are low enough an aqueous process should be something you can bring online and offline rapidly depending on current market rates. Consider Germany already had a few late nights in winder where rates went negative. You can see where I'm going here.
You can't just replace natural gas with hydrogen. Biggest issue is the piping.
Here in the Netherlands we have a lot of natural gas infrastructure (it used to be mandated that every house gets a gas pipe for central heating and cooking). We would like to reuse it for hydrogen, but the pipes we have right now would leak horribly.
Beyond the issues of containing hydrogen, there is another difference. You can't (easily) liquefy hydrogen, whereas liquefied natural gas (LNG) is a big thing.
Yes, but the amount of electrons per gram of carbon is three times as high with CH4 as with C.
CH4 + Fe2O3 >> CO + 2H2O + 2 Fe
3 C + Fe2O3 >> 3 CO + 2 Fe
In air: 2 CO + O2 >> CO2
CO2 is not produced directly at high temperatures because it decomposes at 900 C to CO and O2.
A bigger problem with natural gas is the methane released to the atmosphere when it is extracted. This is actually the largest source of atmospheric methane IIRC.
I'd have figured the methane would be reformed to H2 first:
nominally,
H2O + CH4 -> CO + 3 H2
+ H2O -> CO2 + 4H2
3H2 + FexOy -> H2O + Fe
about 1.2-1.4x the methane winds up as CO2 (some extra is burned for heating in the reforming step). In this order H2 could be just as easily, but far more expensively, produced via green methods.
Another green way would be to use aluminum to refine iron, Al + FexOy -> Fe + Al2O3. Exothermic, rapid, 'green', but expensive because it costs electricity to make Al.
Also to your main point in modern blast furnaces I believe CO is either recycled or allowed to react with Fe2O3 at lower temperature to go all the way to CO2, saving money on coke:
Fe2O3 + 3CO → 2Fe + 3CO2
or
Fe2O3 + 3C -> 4Fe + 3CO2
That's why opposition to gas flaring is ridiculous. It's far better for the environment to burn it and turn leaking methane into CO2 + water vapor than let it escape (even if the burning can't be locally used to power anything).
I cannot speak directly the process described, but hydrogen embrittlement is an effect of exposure of finished metals to hydrogen gas where molecular hydrogen penetrates the metal walls (H2 is a very small and light molecule with a sort of ambiguous electropotential property) and disrupts the metalic structure.
Presumably use in production would avoid this, possibly through oxydising the hydrogen at some point. I'd like to read a more technical metalurgical description though, and am well out of my depth here.
Update: The process Bloomberg describe may be related to the concept of "hydrogen attack", in which hot, high-temperature hydrogen decarburises (reduces/removes carbon in) steel by combining with it to form methane, with the resulting gas then trapped in the metal matrix itself.
It's not clear if/how this process might function in steelmaking itself, though part of that involves decarburisation through the injection of oxygen to the blast furnace.
This could indeed be a big deal. "Coked" coal, or metalurgical coal, accounts for 15% of current (or at least recent-years, the numbers are shifting rapidly as electric generation offloads) global coal use. It's a use that would otherwise be hard to substitute for although there are options.
Previously, the main alternative has been to re-use recycled steel, in electric arc furnaces (hit up https://invido.us for some pretty amazing videos of things going well and/or poorly) which 1) use potentially clean electricity sources and 2) eliminate all coke use. Altneratives to the blast furnace refinement of new steel from iron ore would be a development unprecedented since the introduction of Bessemer process furnaces in the 1860s.
Vaclav Smil writes on many energy and resource topics, and covers steel from both perspectives in his Energy and Civilization and Making the Modern World books. I'd strongly recommend both.
What I'm finding odd with the article is that Bloomberg appear to be principally citing themselves as sources. I'm reviewing literature and there appears to be scientific research dating at least to the 1970s on this topic (that'a a very quick first read by titles).
I'll add possibly relevant links here. Anyone with actual metalurgical knowledge is far better placed to comment than me.
This appears likely the technology in question:
Valentin Vogl, Max Åhman, Lars J. Nilsson,
"Assessment of hydrogen direct reduction for fossil-free steelmaking" (2018)
I'm not sure what you meant to link to with that invido.us link, but when I opened it I got an expired cert, followed by uBlock Origin blocking the whole page, followed by a redirect to a different domain whose above-the-fold content was about Minecraft.
Great, but industrial hydrogen is produced from natural gas.
We need a good alternative source of industrial hydrogen. I have read of catalytic coatings that split water into hydrogen and oxygen, and were considered uneconomical because of the need to process the hydrogen into "something useful". If hydrogen becomes directly useful, the economic equation should balance out differently.
Steel has miniscule amounts of carbon (0.2% is typical). The carbon comes largely from pig iron from the iron making step (where it comes from the coke used to smelt ore) and an oxygen lance is actually used to burn out excess carbon from molten pig iron to reduce the quantity to a level suitable for mild steel.
[1]: https://en.m.wikipedia.org/wiki/Coke_(fuel)