The sponge iron reaction (SIR) is a chemical process based on

redox Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is t ...

cycling of an iron-based contact mass, the first cycle is a conversion step between

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

metal (Fe) and wuestite (FeO), the second cycle is a conversion step between wuestite (FeO) and

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula . It is one of the iron oxide, oxides of iron, and is ferrimagnetism, ferrimagnetic; it is attracted to a magnet and can be magnetization, magnetized to become a ...

(Fe₃O₄). In application, the SIT is used in the reformer sponge iron cycle (RESC) in combination with a

steam reforming Steam reforming or steam methane reforming (SMR) is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly, natural gas is the feedstock. The main purpose of this technology is often hydrogen ...

unit.

Process description

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

Iron-wuestite

+ ↔ +

Magnetite-wuestite

+ ↔ 3 +

Application

The reformer sponge iron cycle is a two step cycle to produce

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

from

hydrocarbon fuel In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic; their odor is usually faint, and may ...

s based SIR and steam.

Reformer sponge iron cycle

In the first step the

is reformed to

syngas Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as ...

in the reformer which is then used to reduce the

iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. Iron ...

(

—Fe₃O₄) to iron (

wüstite Wüstite ( Fe O, sometimes also written as Fe0.95O) is a mineral form of mostly iron(II) oxide found with meteorites and native iron. It has a grey colour with a greenish tint in reflected light. Wüstite crystallizes in the isometric-hexoc ...

—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 A product's service life is its period of use in service. Several related terms describe more precisely a product's life, from the point of manufacture, storage, and distribution, and eventual use. Service life has been defined as "a product' ...

of several thousand

cycles.

References

External links

A thermodynamic analysis of the reformer sponge iron cycleInvestigations on mixed CO₂- and steam reforming of liquid hydrocarbons for the decentralized production of hydrogenSolid biomass gasification for fuel cells (sponge iron reactor SIR)
{{DEFAULTSORT:Sponge Iron Reaction Chemical processes Hydrogen production