Solid oxide fuel cell (SOFC) systems are the most advanced power generation system with the highest thermal efficiency. The current trend of research on the SOFC systems is focused on multikilowatt scale systems, which require either internal reforming within the stack or a compact external reformer. Even if the internal reforming within the SOFC stack allows compact system configuration, it causes significant and complicated temperature gradients within the stack, due to endothermic reforming reactions and exothermic electrochemical reactions. As an alternative solution to the internal reforming, an external compact heat exchange reformer (CHER) is investigated in this work. The CHER is based on a typical plate-fin counterflow or coflow heat exchanger platform, and it can save space without causing large thermal stress and degradation to the SOFC stack (i.e., eventually reducing the overall system cost). In this work, a previously developed transient dynamic model of the CHER is validated by experiments. An experimental apparatus, which comprises the CHER, air heater, gas heater, steam generator, several mass flow controllers, and controller cabinet, was designed to investigate steady state reforming performance of the CHER for various hot air inlet temperatures (thermal energy source) and steam to carbon ratios (SCRs). The transient thermal dynamics of the CHER was also measured and compared with simulations when the CHER is used as a heat exchanger with inert gas. The measured transient dynamics of CHER matches very well with simulations, validating the heat transfer model within the CHER. The measured molar fractions of reformate gases at steady state also agree well with the simulations validating the used reaction kinetics. The transient CHER model can be easily integrated into a total integrated SOFC system, and the model can be also used for optimal design of similar CHERs and provides a guideline to select optimal operating conditions of the CHERs and the integrated SOFC system.

References

References
1.
Mench
,
M. M.
,
2008
,
Fuel Cell Engines
,
Wiley
,
Hoboken, NJ
, pp.
438
441
.
2.
O'Hayre
,
R. P.
,
Cha
,
S.
, and
Colella
,
W.
,
2006
,
Fuel Cell Fundamentals
,
Wiley
,
New York
, pp.
282
304
.
3.
Williams
,
M. C.
, and
George
,
T. J.
,
1992
, “
Research Issues in Molten Carbonate Fuel Cells: Pressurization
,” 27th Intersociety Energy Conversion Engineering Conference (IECEC-92), San Diego, CA, August 3–7, Vol. 3, pp.
263
267
.
4.
Buchanan
,
T.
,
Hirschenhofer
,
J.
, and
Stauffer
,
D.
,
1994
, “
Carbon Dioxide Capture in Fuel Cell Power Systems
,” G/C Report No. 2981.
5.
Ahrned
,
S.
,
Krumpelt
,
M.
,
Kumar
,
R.
,
Lee
,
S.
,
Carter
,
J.
,
Wilkenhoener
,
R.
, and
Marshall
,
C.
,
1998
, “
Catalytic Partial Oxidation Reforming of Hydrocarbon Fuels
,” 1998 Fuel Cell Seminar, Palm Springs, CA, November 16–19.
6.
Pukrushpan
,
J.
,
Stefanopoulou
,
A.
,
Varigonda
,
S.
,
Pedersen
,
L.
,
Ghosh
,
S.
, and
Peng
,
H.
,
2003
, “
Control of Natural Gas Catalytic Partial Oxidation for Hydrogen Generation in Fuel Cell Applications
,”
American Control Conference
, Denver, CO, June 4–6.
7.
Chaniotis
,
A.
, and
Poulikakos
,
D.
,
2005
, “
Modeling and Optimization of Catalytic Partial Oxidation Methane Reforming for Fuel Cells
,”
J. Power Sources
,
142
, pp.
184
193
.10.1016/j.jpowsour.2004.10.018
8.
Cavallaro
,
S.
, and
Freni
,
S.
,
1998
, “
Syngas and Electricity Production by an Integrated Autothermal Reforming/Molten Carbonate Fuel Cell System
,”
J. Power Sources
,
76
(
2
), pp.
190
196
.10.1016/S0378-7753(98)00165-7
9.
Achenbach
,
E.
,
1994
, “
Three-Dimensional and Time-Dependent Simulation of a Planar Solid Oxide Fuel Cell Stack
,”
J. Power Sources
,
49
, pp.
333
348
.10.1016/0378-7753(93)01833-4
10.
Peters
,
R.
,
Dahl
,
R.
,
Kluttgen
,
U.
,
Palm
,
C.
, and
Stolten
,
D.
,
2002
, “
Internal Reforming of Methane in Solid Oxide Fuel Cell Systems
,”
J. Power Sources
,
106
, pp.
238
244
.10.1016/S0378-7753(01)01039-4
11.
Agnew
,
G. D.
,
Bernardi
,
D.
,
Collins
,
R. D.
, and
Cunningham
,
R. H.
,
2006
, “
An Internal Reformer for a Pressurised SOFC System
,”
J. Power Sources
,
157
, pp.
832
836
.10.1016/j.jpowsour.2005.11.101
12.
Nikooyeh
,
K.
,
Ayodeji
,
A.
,
Jeje
,
A.
, and
Hill
,
J. M.
,
2007
, “
3D Modeling of Anode-Supported Planar SOFC With Internal Reforming of Methane
,”
J. Power Sources
,
171
, pp.
601
609
.10.1016/j.jpowsour.2007.07.003
13.
Colpan
,
C.
,
Dincer
, I
.
, and
Hamdullahpur
,
F.
,
2007
, “
Thermodynamic Modeling of Direct Internal Reforming Solid Oxide Fuel Cells Operating With Syngas
,”
Int. J. Hydrogen Energy
,
32
, pp.
787
795
.10.1016/j.ijhydene.2006.10.059
14.
Assabumrungrat
,
S.
, and
Laosiripojana
,
N.
,
2005
, “
Thermodynamic Analysis of Carbon Formation in a Solid Oxide Fuel Cell With a Direct Internal Reformer Fuelled by Methanol
,”
J. Power Sources
,
139
, pp.
55
60
.10.1016/j.jpowsour.2004.06.065
15.
Friedle
,
U.
, and
Veser
,
G.
,
1999
, “
A Counter-Current Heat Exchange Reactor for High Temperature Partial Oxidation Reactions
,”
Chem. Eng. Sci.
,
54
, pp.
1325
1332
.10.1016/S0009-2509(99)00061-5
16.
Patel
,
K. S.
, and
Sunol
,
A. K.
,
2006
, “
Dynamic Behavior of Methane Heat Exchange Reformer for Residential Fuel Cell Power Generation System
,”
J. Power Sources
,
161
, pp.
503
512
.10.1016/j.jpowsour.2006.03.061
17.
Pan
,
L.
, and
Wang
,
S.
,
2005
, “
Modeling of a Compact Plate-Fin Reformer for Methanol Steam Reforming in Fuel Cell Systems
,”
Chem. Eng. J.
,
108
, pp.
51
58
.10.1016/j.cej.2004.12.042
18.
Anxionnaz
,
Z.
,
Cabassud
,
M.
,
Gourdon
,
C.
, and
Tochon
,
P.
,
2008
, “
Heat Exchanger/Reactors (HEX Reactors): Concepts, Technologies: State-of-the-Art
,”
Chem. Eng. Process.
,
47
(
12
), pp.
2029
2050
.10.1016/j.cep.2008.06.012
19.
Zhang
,
H.
,
Wang
,
L.
,
Weng
,
S.
, and
Su
,
M.
,
2008
, “
Performance Research on the Compact Heat Exchange Reformer Used for High Temperature Fuel Cell Systems
,”
J. Power Sources
,
183
, pp.
282
294
.10.1016/j.jpowsour.2008.04.068
20.
Ki
,
J.
, and
Kim
,
D.
,
2010
, “
Computational Model to Predict Thermal Dynamics of Planar Solid Oxide Fuel Cell Stack During Start-Up Process
,”
J. Power Sources
,
195
, pp.
3186
3200
.10.1016/j.jpowsour.2009.11.129
21.
Ki
,
J. P.
,
2013
, “
Integrated Modeling Approach for Solid Oxide Fuel Cell-Based Power Generating System
,” Ph.D. thesis, University of Texas at Arlington, Arlington, TX.
22.
Ki
,
J.
,
Kim
,
D.
, and
Honavara-Prasad
,
S.
,
2012
, “
Dynamic Modeling of a Compact Heat Exchange Reformer for High Temperature Fuel Cell Systems
,”
ASME J. Fuel Cell Sci. Technol.
,
9
, p.
011013
.10.1115/1.4004709
23.
Xu
,
J.
, and
Froment
,
G.
,
1989
, “
Methane Steam Reforming, Methanation and Water-Gas Shift: 1. Intrinsic Kinetics
,”
AIChE J.
,
35
(
1
), pp.
88
96
.10.1002/aic.690350109
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