Hydrogen Direct Reduction of Iron — H2-DRI Shaft Furnace

Furnace Controls

Shaft temperature 850 °C

H₂ purity in reducing gas 95%

Pellet feed rate 1.0×

Live Readouts

Metallization (exit)

Residence time

0 min

H₂ consumed

0 kg/t

CO₂ avoided vs BF-BOF

0 kg/t

Hematite / wüstite (unreduced)

Metallic sponge iron (Fe)

H₂ gas rising through bed

How it works

In a hydrogen direct-reduction (H2-DRI) shaft furnace, solid iron-ore pellets (mostly Fe₂O₃, hematite) are fed in at the top and sink slowly downward while hot reducing gas — mostly H₂, made by electrolysing water with renewable electricity — flows counter-current, upward through the bed:

Fe₂O₃ + 3 H₂ → 2 Fe + 3 H₂O    (ΔH ≈ +99 kJ/mol, endothermic)

This replaces the classic blast-furnace route, which reduces ore with carbon monoxide from coke:

Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂    (releases CO₂ instead of H₂O)

Each pellet's conversion is modelled with a shrinking-core-style first-order rate law. The local rate constant follows an Arrhenius form in furnace temperature T, and scales with the partial pressure (purity) of H₂ in the gas:

dx/dt = k(T) · f(H₂%) · (1 − x)
k(T)  = A · exp(−Ea / (R·T))

Temperature — raises k(T) exponentially; industrial shaft furnaces run roughly 700–950 °C to stay below softening/clustering limits of the pellets.
H₂ purity — a leaner reducing gas (more inert/residual gas mixed in) lowers the effective driving force and slows conversion.
Feed rate — a faster feed shortens the time each pellet spends in the shaft, so if it outruns the kinetics the exiting pellets are less metallized.

Because the reducing agent is H₂ instead of carbon, the exhaust is water vapour rather than CO₂ — when the hydrogen itself is made with low-carbon electricity, this route can cut ironmaking's direct CO₂ emissions by roughly 90% versus the coke blast-furnace + basic-oxygen-furnace path, which is why it is one of the most closely watched decarbonization technologies in heavy industry.

Zone: reduction (mid-shaft) Pellets tracked: 0

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