DRI PROCESS


DRI process

Where natural gas is abundant, direct reduction iron (DRI) is made from iron ore and a reduction in gas is delivered by reforming natural gas. Reliable reducing gas delivery is critical. Johnson Matthey's reforming catalysts and upstream natural gas purification products make an invaluable contribution to DRI operations.

In contrast to steam reformers which are designed to produce hydrogen, the reformer on a direct reduction plant is fed by a carbon dioxide rich feed gas. The water concentration in the feed gas is also relatively low since the gas produced by the reformer must be very lean in oxidants in order to allow full reduction of the iron ore within the shaft furnace. Hence, in these type of reformers there is a significant risk of carbon deposition from the higher hydrocarbon tail in the natural gas feed. Furthermore, the high carbon monoxide concentrations, which are produced by the carbon dioxide reforming reaction, lead to the possibility of Boudouard carbon formation.

CO2 + CH4 ⇔ 2CO + 2H2
2CO ⇔ C + CO2

In order to overcome these problems a range of robust catalysts which have carefully engineered activities are required in order to resist carbon deposition. Johnson Matthey provides a range of low pressure drop, shaped, DYCAT catalysts to allow tailored catalytic activity throughout the reformer tube. The DYCAT products also employ alkaline oxides constituents such as lanthanum oxides to neutralize catalyst surface acidity and to thereby reduce any acid promoted carbon forming reactions.

 

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