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It is going to be very costly (energy and capital investment) to convert steel making to use hydrogen. A blast furnace is a well balanced chemical reaction wher

It is going to be very costly (energy and capital investment) to convert steel making to use hydrogen. A blast furnace is a well balanced chemical reaction where the coke serves two purposes; a source of carbon monoxide for turning ore in iron (Fe2O3(s) + 3 CO(g) => 2 Fe(s) + 3 CO2(g), very exothermic, good for turning the iron / steel into a liquid alloy), and a source of carbon for turning the iron into steel. All in one vessel and in one process no less. I guess you could do the first step using peroxide to strip the oxygen from the iron, but the second step in the same vessel at the same time? Fe2o3 + 3H2O2 => 2 Fe + 3 H2O, somewhat exothermic (if my rusty memory of enthalpy calculations are correct), not sure of the activation energy or need for catalysts). [EDIT] also forgot the peroxide reaction would probably require external heat to over come the latent energy required to turn the H2O into super heated steam so that you could melt the iron / steel. This would probably boil off a large chunk of the peroxide as well, so it might need to be done in a contained pressure vessel, which would probably affect the speed of the iron ore reduction.

ClumsyPilot 6y ago
There is a steel mill that uses hydrogen, but it appears to be a recycling kind, rather than one that makes iron from ore with a blast furnace. https://www.rechargenews.com/transition/-world-first-as-hydrogen-used-to-power-commercial-steel-production/2-1-799308 https://www.rechargenews.com/transition/-world-first-as-hydr...
- tankenmate 6y ago
  Yes, I suspect this is much easier as you don't need to alloy as the steel is already alloyed with carbon.
_ph_ 6y ago
I am not a steel expert, but the steel industry is constantly talking about converting to hydrogen. Your sum formula has a bit lot of oxygen, shouldn't it be Fe2O3+3H2 => 2 Fe + 2 H2O? In any case, they could use additional hydrogen for heating and burning it with ambient air.
- tankenmate 6y ago
  I suggested using peroxide not hydrogen, as the peroxide reaction is more exothermic. Either way I suspect that you'd need to burn a lot of extra hydrogen to overcome the latent heat of water and create sufficient heat to melt the ore / alloy. A quick back of the envelope calculation would be at least 1 million litres of H2 per ton of steel. So maybe 2~3 million litres of H2 per manufactured car just for the steel alone? [EDIT] Peroxide also has the added benefit of being a liquid at room temperature.
  - _ph_ 6y ago
    Yes, peroxide being liquid certainly is nice, being a light gas is certainly one major obstacle in using H2. However I am surprised that the peroxide reaction would be more exothermic, as you would have to break the hydrogen from the peroxide first. 1 million litres of H2 are just 90kg though, that isn't that much for a ton of steel.
    - tankenmate 6y ago
      It is only a bit more exothermic, about 20% more (again from my rusty enthalpy calculations). The downside of course is making the peroxide in the first place. Also, peroxide is relatively safe (compared to gaseous hydrogen) to handle up to ~150C.
  - smegger001 6y ago
    I am reminded of the classic article "things I Won't Work With" by chemist Derek Lowe on the subject of Peroxides https://blogs.sciencemag.org/pipeline/archives/2014/10/10/things_i_wont_work_with_peroxide_peroxides https://blogs.sciencemag.org/pipeline/archives/2014/10/10/th.... they don't sound safe
hannob 6y ago
Look here: https://www.hybritdevelopment.com/ https://www.hybritdevelopment.com/ Particularly the "Downloads" section, they have quite a bit of info reasonably easy to digest for interested lay people. It may be expensive, but it's pretty much the only game in town. The only possible alternative is direct electrolysis, but that's even less developed. The hydrogen path is from what I understand technically not that much different from direct reduced iron with natural gas, which is something that already is in use for a significant chunk of steel production.
- tankenmate 6y ago
  Thanks, it's a good source. Also on the financial front of how they organised finance and created a route to market.
ehnto 6y ago
The biggest steel mill in my state is switching to locally sourced green hydrogen. Written out, that sounds pretty funny. But it's produced with local solar energy farms, so it's pretty accurate. This is one area where carbon taxes are the obvious solution. Cost and availability is the biggest driving factor for industry. Furnace coal is available and cheap, but if you tax it heavily for it's emissions enough it won't be. Will steel become extinct? Of course not, the mills will switch to the next alternative, which is hydrogen. It will be ripe with opportunity, with solar farms and hydrogen plants popping up around steel mills. Already we are seeing coal plants written off as unprofitable and future mining projects are becoming less attractive to investors in an unpredictable future. Even without a carbon tax, we could see the cost of coal go up enough to make a local hydrogen industry make more sense. But we can speed the whole process up with smart carbon taxes.
jillesvangurp 6y ago
The "Just have a think" youtube channel did a nice episode on this topic last week: https://www.youtube.com/watch?v=ywHJt88H5YQ https://www.youtube.com/watch?v=ywHJt88H5YQ Apparently there are several viable ways to make clean energy work in this space. And there are some companies starting to do some of this already. Carbon prices is short term going to be needed to cover the price difference. But the cool thing is that it boils down to cost per MWH of energy per tonne of steel. As that goes down, it becomes more viable and eventually cheaper.
philipkglass 6y ago
Fe2o3 + 3H2O2 => 2 Fe + 3 H2O This is not balanced correctly. There are 9 oxygen atoms on the left hand and only 3 oxygen atoms on the right hand. Hydrogen peroxide can act as a reducing agent relative to some things, like permanganate anions, but it's an oxidizing agent relative to metallic iron. Hydrogen peroxide cannot substitute for coal or hydrogen in steel production.
- tankenmate 6y ago
  Yup, you're right, rusty chemistry on my part.

ClumsyPilot 6y ago

There is a steel mill that uses hydrogen, but it appears to be a recycling kind, rather than one that makes iron from ore with a blast furnace. https://www.rechargenews.com/transition/-world-first-as-hydrogen-used-to-power-commercial-steel-production/2-1-799308 https://www.rechargenews.com/transition/-world-first-as-hydr...

tankenmate 6y ago
Yes, I suspect this is much easier as you don't need to alloy as the steel is already alloyed with carbon.

_ph_ 6y ago

I am not a steel expert, but the steel industry is constantly talking about converting to hydrogen. Your sum formula has a bit lot of oxygen, shouldn't it be Fe2O3+3H2 => 2 Fe + 2 H2O? In any case, they could use additional hydrogen for heating and burning it with ambient air.

tankenmate 6y ago
I suggested using peroxide not hydrogen, as the peroxide reaction is more exothermic. Either way I suspect that you'd need to burn a lot of extra hydrogen to overcome the latent heat of water and create sufficient heat to melt the ore / alloy. A quick back of the envelope calculation would be at least 1 million litres of H2 per ton of steel. So maybe 2~3 million litres of H2 per manufactured car just for the steel alone? [EDIT] Peroxide also has the added benefit of being a liquid at room temperature.
- _ph_ 6y ago
  Yes, peroxide being liquid certainly is nice, being a light gas is certainly one major obstacle in using H2. However I am surprised that the peroxide reaction would be more exothermic, as you would have to break the hydrogen from the peroxide first. 1 million litres of H2 are just 90kg though, that isn't that much for a ton of steel.
  - tankenmate 6y ago
    It is only a bit more exothermic, about 20% more (again from my rusty enthalpy calculations). The downside of course is making the peroxide in the first place. Also, peroxide is relatively safe (compared to gaseous hydrogen) to handle up to ~150C.
- smegger001 6y ago
  I am reminded of the classic article "things I Won't Work With" by chemist Derek Lowe on the subject of Peroxides https://blogs.sciencemag.org/pipeline/archives/2014/10/10/things_i_wont_work_with_peroxide_peroxides https://blogs.sciencemag.org/pipeline/archives/2014/10/10/th.... they don't sound safe

hannob 6y ago

Look here: https://www.hybritdevelopment.com/ https://www.hybritdevelopment.com/ Particularly the "Downloads" section, they have quite a bit of info reasonably easy to digest for interested lay people. It may be expensive, but it's pretty much the only game in town. The only possible alternative is direct electrolysis, but that's even less developed. The hydrogen path is from what I understand technically not that much different from direct reduced iron with natural gas, which is something that already is in use for a significant chunk of steel production.

tankenmate 6y ago
Thanks, it's a good source. Also on the financial front of how they organised finance and created a route to market.

ehnto 6y ago

The biggest steel mill in my state is switching to locally sourced green hydrogen. Written out, that sounds pretty funny. But it's produced with local solar energy farms, so it's pretty accurate. This is one area where carbon taxes are the obvious solution. Cost and availability is the biggest driving factor for industry. Furnace coal is available and cheap, but if you tax it heavily for it's emissions enough it won't be. Will steel become extinct? Of course not, the mills will switch to the next alternative, which is hydrogen. It will be ripe with opportunity, with solar farms and hydrogen plants popping up around steel mills. Already we are seeing coal plants written off as unprofitable and future mining projects are becoming less attractive to investors in an unpredictable future. Even without a carbon tax, we could see the cost of coal go up enough to make a local hydrogen industry make more sense. But we can speed the whole process up with smart carbon taxes.

jillesvangurp 6y ago

The "Just have a think" youtube channel did a nice episode on this topic last week: https://www.youtube.com/watch?v=ywHJt88H5YQ https://www.youtube.com/watch?v=ywHJt88H5YQ Apparently there are several viable ways to make clean energy work in this space. And there are some companies starting to do some of this already. Carbon prices is short term going to be needed to cover the price difference. But the cool thing is that it boils down to cost per MWH of energy per tonne of steel. As that goes down, it becomes more viable and eventually cheaper.

philipkglass 6y ago

Fe2o3 + 3H2O2 => 2 Fe + 3 H2O This is not balanced correctly. There are 9 oxygen atoms on the left hand and only 3 oxygen atoms on the right hand. Hydrogen peroxide can act as a reducing agent relative to some things, like permanganate anions, but it's an oxidizing agent relative to metallic iron. Hydrogen peroxide cannot substitute for coal or hydrogen in steel production.

tankenmate 6y ago
Yup, you're right, rusty chemistry on my part.