Sponge iron reaction

The sponge iron reaction (SIR) is a chemical process based on redox cycling of an iron-based contact mass, the first cycle is a conversion step between iron metal (Fe) and wuestite (FeO), the second cycle is a conversion step between wuestite (FeO) and magnetite (Fe₃O₄).^[1] In application, the SIT is used in the reformer sponge iron cycle (RESC) in combination with a steam reforming unit.

Process description

The process has two modes, a reduction mode and an oxidation mode.

Iron-wuestite

FeO + H
2 ↔ Fe + H
2O

Magnetite-wuestite

Fe
3O
4 + H
2 ↔ 3FeO + H
2O

Application

The reformer sponge iron cycle is a two step cycle to produce hydrogen from hydrocarbon fuels based SIR and steam.^[2]

Reformer sponge iron cycle

In the first step the hydrocarbon fuel is reformed to syngas in the reformer which is then used to reduce the iron oxide (magnetite—Fe₃O₄) to iron (wüstite—FeO), in the second step steam is utilized to re-oxidise the iron into magnetite and hydrogen. The iron oxide pellets are placed in a pelletbed and have a service life of several thousand redox cycles.^[3]

See also

• Packed bed
• Steam reforming

References

1. Sponge iron process for manned space exploration
2. A novel process for stationary hydrogen production: the reformer sponge iron cycle
3. First investigations of structural changes of the contact mass in the RESC process for hydrogen production

External links

• A thermodynamic analysis of the reformer sponge iron cycle
• Investigations on mixed CO₂- and steam reforming of liquid hydrocarbons for the decentralized production of hydrogen
• Solid biomass gasification for fuel cells (sponge iron reactor SIR)