Water Gas Shift Reaction
This subnode is available to the H2 Gas Phase node when H2O, CO, and CO2 have all been selected, along with Include gas phase diffusion in the H2 Gas Mixture on the interface top node.
The water gas shift reaction defines the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen according to
The water gas shift reaction is of particular interest for fuel cells operating on fuel stemming from hydrocarbon reformation, containing significant amounts of carbon dioxide and carbon monoxide. The reaction is also of general interest in molten carbonate fuel cells and electrolyzers, due to the presence of carbon dioxide in the hydrogen fuel/product fluid stream.
The node may be used for adding an additional mass source due to water gas shift reaction, such as in a molten carbonate fuel cell. The Water Gas Shift Reaction Rate may be defined using the From mass action law or by a User defined expression. The node contains text fields for specifying the Rate constant and Reference pressure, in case of the default From mass action law option. The rate expression is added to the rate variables for the gaseous species (based on the reaction stoichiometry), which are in turn used in the domain equations for diffusion. Since the reaction does not involve phase changes, the total mass source from the water gas shift reaction is zero, and no contribution is hence made to the momentum equation.
The Heat of reaction is calculated automatically when the Built in option is used.
The default selection is all domains of the parent node, but may be changed.