7 ms·

This is a process for refining iron ore, as opposed to using a blast furnace, or using the same process with decomposed natural gas instead of just hydrogen. In

This is a process for refining iron ore, as opposed to using a blast furnace, or using the same process with decomposed natural gas instead of just hydrogen. In steel production it would be subsequently smelted.

lazide 4y ago
Do you think that removes the concern? I don’t see how it would.
- photochemsyn 4y ago
  This process produces sponge iron, which is then fed into an electric arc furnace. There is no free hydrogen around at that point. Whatcomes out of an electric arc furnace is carbon steel. The issue with hydrogen, which was first noted IIRC in the high-pressure Haber-Bosch ammonia production process, in which H2 and N2 at high pressure over a catalyst in a steel chamber forms NH3, is that free hydrogen reacts with the carbon in the steel under these conditions, which caused the pressure chambers to regularly explode (solution was a sacrificial lining of the chambers which was regularly replaced). For low-pressure H2 it may not be much of a problem, but that's not very efficient for transport.
  - lazide 4y ago
    Thanks for the background! So likely due to the complete remelt and re-alloying expected, it should work out?
  - pstuart 4y ago
    Speaking of ammonia, any thoughts to share on an ammonia economy vs hydrogen economy? The former seems a lot more practical.
    - photochemsyn 4y ago
      Ammonia as fertilizer is the only ammonia economy that makes sense; hydrogen economy doesn't make much sense either. Methane economy is the optional long-term solution for chemical energy sources, just CO2(atm) + H2 (water) -> CH4. Ammonia combustion generates NOx smog, and ammonia is pretty toxic to store and transport as a gas. For fertilizer it's stored as (NH4)(NO3) or similar. Hydrogen production has a few major use cases, but replacing natural gas is not one of them. Iron reduction, nitrogen reduction, carbon reduction, in industrial settings, is about it.
      - pstuart 4y ago
        Thanks!

lazide 4y ago

Do you think that removes the concern? I don’t see how it would.

photochemsyn 4y ago
This process produces sponge iron, which is then fed into an electric arc furnace. There is no free hydrogen around at that point. Whatcomes out of an electric arc furnace is carbon steel. The issue with hydrogen, which was first noted IIRC in the high-pressure Haber-Bosch ammonia production process, in which H2 and N2 at high pressure over a catalyst in a steel chamber forms NH3, is that free hydrogen reacts with the carbon in the steel under these conditions, which caused the pressure chambers to regularly explode (solution was a sacrificial lining of the chambers which was regularly replaced). For low-pressure H2 it may not be much of a problem, but that's not very efficient for transport.
- lazide 4y ago
  Thanks for the background! So likely due to the complete remelt and re-alloying expected, it should work out?
- pstuart 4y ago
  Speaking of ammonia, any thoughts to share on an ammonia economy vs hydrogen economy? The former seems a lot more practical.
  - photochemsyn 4y ago
    Ammonia as fertilizer is the only ammonia economy that makes sense; hydrogen economy doesn't make much sense either. Methane economy is the optional long-term solution for chemical energy sources, just CO2(atm) + H2 (water) -> CH4. Ammonia combustion generates NOx smog, and ammonia is pretty toxic to store and transport as a gas. For fertilizer it's stored as (NH4)(NO3) or similar. Hydrogen production has a few major use cases, but replacing natural gas is not one of them. Iron reduction, nitrogen reduction, carbon reduction, in industrial settings, is about it.
    - pstuart 4y ago
      Thanks!