Exercises
239
The goal of this exercise is to study the different chemical or electrochemical
reactions that occur at the electrodes of a SOFC supplied with an arbitrary
hydrocarbon fuel C n H m .
This exercise does not take into account the kinetic aspects of the reactions.
1. Write the electrode reactions and the overall reaction of the cell assuming
hydrogen operation.
2. Chemical oxidation reactions
a. Write the following reactions assuming methane operation and generalize
to the case of an arbitrary hydrocarbon C n H m . Apply these reactions to
the case of butane C 4 H 10 .
2 water vapor reforming reaction,
2 carbon dioxide reforming reaction,
2 cracking reaction,
2 chemical partial oxidation reaction.
b. Write the additional reactions that could occur at the anode.
3. Direct electrochemical oxidation reactions
a. Give the electrode reactions and the overall cell reaction for a SOFC
operating on methane in the case of total electrochemical oxidation and
in the case of partial electrochemical oxidation (formation of CO and
H 2 O).
b. Give the electrode reactions and the overall cell reaction when operating
on an arbitrary hydrocarbon fuel C n H m for the two following cases and
apply these reactions to the case of propane C 3 H 8 and but-2-ene C 4 H 8 :
2 total electrochemical oxidation,
2 partial electrochemical oxidation.
c. Write the expression for the emf of a cell under total electrochemical
oxidation and partial electrochemical oxidation
2 for an arbitrary hydrocarbon C n H m ,
2 for an alkane with formula C n H 2n+2 .
Exercise 5.18 – Thermodynamic study of methane reforming in SOFC
A SOFC can operate directly with methane through various processes, notably
internal reforming by water vapor (steam reforming), whose chemical equation is
CH 4 + H 2 O m CO + 3H 2
239
The goal of this exercise is to study the different chemical or electrochemical
reactions that occur at the electrodes of a SOFC supplied with an arbitrary
hydrocarbon fuel C n H m .
This exercise does not take into account the kinetic aspects of the reactions.
1. Write the electrode reactions and the overall reaction of the cell assuming
hydrogen operation.
2. Chemical oxidation reactions
a. Write the following reactions assuming methane operation and generalize
to the case of an arbitrary hydrocarbon C n H m . Apply these reactions to
the case of butane C 4 H 10 .
2 water vapor reforming reaction,
2 carbon dioxide reforming reaction,
2 cracking reaction,
2 chemical partial oxidation reaction.
b. Write the additional reactions that could occur at the anode.
3. Direct electrochemical oxidation reactions
a. Give the electrode reactions and the overall cell reaction for a SOFC
operating on methane in the case of total electrochemical oxidation and
in the case of partial electrochemical oxidation (formation of CO and
H 2 O).
b. Give the electrode reactions and the overall cell reaction when operating
on an arbitrary hydrocarbon fuel C n H m for the two following cases and
apply these reactions to the case of propane C 3 H 8 and but-2-ene C 4 H 8 :
2 total electrochemical oxidation,
2 partial electrochemical oxidation.
c. Write the expression for the emf of a cell under total electrochemical
oxidation and partial electrochemical oxidation
2 for an arbitrary hydrocarbon C n H m ,
2 for an alkane with formula C n H 2n+2 .
Exercise 5.18 – Thermodynamic study of methane reforming in SOFC
A SOFC can operate directly with methane through various processes, notably
internal reforming by water vapor (steam reforming), whose chemical equation is
CH 4 + H 2 O m CO + 3H 2