The water-gas shift reaction (WGS/Dussan Reaction) is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen:

CO + H₂O → CO₂ + H₂

The water-gas shift reaction is an important industrial reaction. It is often used in conjunction with steam reforming of methane or other hydrocarbons,^[1] which is important for the production of high purity hydrogen for use in ammonia synthesis. The water-gas shift reaction was discovered by Italian physicist Felice Fontana in 1780. The reaction is slightly exothermic, yielding 42 kJ (10 kcal) per mole.^[1]

The carbon monoxide can also be generated by bogs or other waste regenerative means by physical/chemical processes such as bog and landfill fires.

Contents 1 Applications 2 Reaction Conditions 3 Catalysts 4 See also 5 References

[edit] Applications

This reaction has been used as a CO removal method from the reformate for fuel cell applications.

The reverse water gas shift reaction has recently found a possible application in In-Situ Resource Utilization on Mars to provide oxygen for fuel for the Mars Direct mission concept.

[edit] Reaction Conditions

The water gas shift reaction is sensitive to temperature, with the tendency to shift towards reactants as temperature increases due to Le Chatelier's principle. In fuel-rich hydrocarbon combustion processes, the water gas reaction at equilibrium state is often employed as a means to provide estimates for molar concentrations of burnt gas constituents.

The process is often used in two stages, stage one a high temperature shift (HTS) at 350 °C (662 °F) and stage two a low temperature shift (LTS) at 190–210 °C (374–410 °F).^[2] Standard industrial catalysts for this process are iron oxide promoted with chromium oxide for the HTS step and copper on a mixed support composed of zinc oxide and aluminum oxide for the LTS shift step.^[3]

[edit] Catalysts

Attempts to lower the reaction temperature of this reaction have been done primarily with a catalyst such as Fe₃O₄ (magnetite), or other transition metals and transition metal oxides. Another catalyst is the Raney copper catalyst.^[4]

[edit] See also

• Water gas
• In-Situ Resource Utilization
• Lane hydrogen producer
• PROX
• Gasification, gasifier, pyrolysis, pyrolyser

[edit] References

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