Compressor 4.3.1
Unused hydrogen from the fuel cell outlet may be used to reduce the fuel requirement at the steam reformer inlet, thus: a) In the last stage of the reforming process c) Ratio of theoretical air to fuel ratio at the reformer inlet (needed for complete combustion) and actual air to fuel ratio 9Īir bleed is process of adding additional air to eliminate CO: a) Ratio of theoretical air flow rate in the reformer (needed for complete reformation) and actual air flow rate c) Improves the efficiency of the reforming process b) Reformate from authothermal reforming contains no water vapor c)
Reformate from steam reforming does not contain nitrogen b) The difference between reformate produced by steam reforming and reformate produced by autothermal reforming is: a)
Hydrogen consumption is higher than in dead-end mode operation 6 Hydrogen flow rate at the stack inlet has stoichiometric ratio higher than 1 c) Hydrogen flow rate at the stack inlet has stoichiometric ratio of 1 b) In a fuel cell system with hydrogen recirculation: a) Only if additional hydrogen is burned and this hot gas is used to run the expander 5 If the pressure drop is sufficiently low c) Only if the fuel cell system operates at high pressure and high temperature b) May need additional heat depending on operating pressure and temperature 4Īn expander may generate enough power to run the compressor: a) Humidification of air in a fuel cell system: a)ĭoes not need additional heat in pressurized systems c) In a fuel cell system, compressor power consumption: a)ĭelivers air at a pressure higher than the fuel cell backpressure c)ĭelivers air at a pressure equal to the fuel cell backpressure 3