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5 – Applications
2 Chemical partial oxidation reaction
• For methane
CH 4 + 2
1
O 2 m CO + 2H 2
• For an arbitrary hydrocarbon C n H m
C n H m +
n
2 O 2 m nCO +
m
2 H 2
• Applied to butane C 4 H 10
C 4 H 10 + 2O 2 m 4CO + 5H 2
b. Because of the formation of carbon monoxide and of solid carbon, the
additional reactions possible at the anode are
2 electrochemical oxidation of carbon monoxide
2CO + 2O
2−
m 2CO 2 + 4e
2 chemical oxidation of carbon monoxide
2CO + O 2 m 2CO 2
2 the disproportionation of carbon monoxide (Boudouard reaction)
2CO m CO 2 + C
2 the water-gas shift reaction
CO + H 2 O m CO 2 + H 2
2 electrochemical oxidation of carbon
C + O
2−
m CO + 2e
C + 2O
2−
m CO 2 + 4e
2 carbon steam reforming
C + H 2 O m CO + H 2
3. Direct electrochemical oxidation reactions
a. Electrode reactions and overall reaction for SOFC-type cell fueled by
methane and operating by total electrochemical oxidation and partial
electrochemical oxidation
2 Total electrochemical oxidation
• at the anode
CH 4 + 4O
2−
m CO 2 + 2H 2 O + 8e