ABSTRACT
The rate of the homogeneous water-gas shift reaction in the gas phase is very low at practical temperatures, but in 1912 Bosch and Wild140 discovered a catalyst consisting of oxides of iron and chromium that could be used at 400–500°C to reduce the carbon monoxide to around 2%. The catalytic water-gas shift reaction was incorporated into the first coal-based ammonia process flowsheet in 1915, and since then it has played a vital role in the ammonia process flowsheet. Fewer publications have appeared on the mechanism and kinetics of the water-gas shift reaction over copper-based catalysts than over high-temperature iron-based catalysts, but similar types of kinetic expressions have been proposed. A wide range of reactor designs and flowsheet configurations are possible for the water-gas shift stage in ammonia and hydrogen plants. Copper-based catalysts have good activity for the water-gas shift reaction, and have no methanation activity so they are well suited for use in water-gas shift duties.
