The water gas shift reaction Water-Gas Shift Reaction (WGS) is a chemical reaction that plays a central role in the production of hydrogen from hydrocarbons or coal. It is typically used as a secondary reaction in processes such as Steam reforming employed.
meaning of the reaction
- Increasing hydrogen yield:
It converts carbon monoxide, a byproduct of steam reforming, into hydrogen, which increases the efficiency of the overall process. - Reduction of carbon monoxide levels:
CO is toxic and must be removed in applications such as fuel cells.
reaction conditions
The water gas shift reaction takes place in two stages to ensure optimal hydrogen production:
- High Temperature Shift (HTS):
- Temperature: 300-450°C
- Catalyst: iron oxide (Fe₃O₄) with chromium oxide (Cr₂O₃) as promoter
- Goal: Rapid conversion of CO to CO₂ and H₂
- Low Temperature Shift (LTS):
- Temperature: 200-250°C
- Catalyst: copper oxide (CuO) with zinc oxide (ZnO) and aluminum oxide (Al₂O₃)
- Goal: Maximizing the hydrogen content through further CO conversion
Applications
The water gas shift reaction is mainly used in hydrogen production processes, e.g.:
- Steam reforming: After the primary reaction to produce hydrogen.
- Coal gasification: In the conversion of coal into synthesis gas (CO and H₂).
- Fuel cells: To clean the fuel, as CO can poison the fuel cell catalysts.
