Performance comparison of cocurrent and countercurrent flow solid oxide fuel cells

Abstract

Solid oxide fuel cell (SOFC) is a complicated system with heat and mass transfer as well as electrochemical reactions. The flowing configuration of fuel and oxidants in the fuel cell will greatly affect the performance of the fuel cell stack. Based on the developed mathematical model of direct internal reforming SOFC, this paper established a distributed parameters simulation model for cocurrent and countercurrent types of SOFC based on the volume-resistance characteristic modeling method. The steady-state distribution characteristics and dynamic performances were compared and were analyzed for cocurrent and countercurrent types of SOFCs. The results indicate that the cocurrent configuration of SOFC is more suitable with regard to performance and safety.

Key words： solid oxide fuel cell (SOFC); cocurrent; countercurrent; dynamic performance

Acknowledgments.

This work was supported by the National Natural Science Foundation of China (Grant No. 50676061), the Program of Shanghai Subject Chief Scientist (No. 08XD14021) and the Science and Technology Committee of Shanghai Municipal (Nos. 09DZ1200702, 08DZ1200403).

Notations
F	Molar flow rate/(mol·s-1)
G	Mass flow rate/(kg·s-1)
H	Specific enthalpy/(kJ·kg-1)
k	Ratio of the special heats of the air
p	Pressure/Pa
Pw	Power/kW
T	Temperature/K
t	Time/s
U	Voltage/V
I	Reaction I
II	Reaction II
III	Reaction III
IV	Reaction IV
Greek symbols
ρ	Density/(kg·m-3)
η	Efficiency
ϵ	Pressure loss coefficient
π	Compression ratio
Δp	Pressure loss/Pa
ΔH	Enthalpy change of reaction/(kJ·mol-1)
Subscripts
0	Standard state
1	Inlet
2	Outlet
a	Air
c	Compressor
f	Fuel
g	Reacted gas

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