Improving the dynamic response of the steam reformer in a fuel cell power plant designed for transportation applications will enable the power plant to operate in a transient manner with a reduced need for supplementary batteries and their associated cost, weight, and life cycle limitations. As a method of seeking improvements to the dynamic response, a sixth-order dynamic model of a steam reformer is used with a design optimization process to determine the values of the steam reformer design parameters which will yield the fastest response time to a step input in hydrogen demand under a variety of initial conditions. Results of this analysis suggest that a steam reformer designed to have a maximum output of approximately 12,600 mol/h of hydrogen and optimized for fast response could have response times on the order of 15–20 s. A sensitivity analysis suggests that this response can be achieved primarily by reducing the thermal capacity of the reformer and improving the rate of heat transfer to the gaseous constituents within the reformer. With a steam reformer response time on the order of 15–20 s, supplementary energy storage devices, such as the ultracapacitor and flywheel, become more feasible. These devices are attractive because they have superior life cycle and power density characteristics when compared with traditional chemical batteries.

1.
Ahmed, S., Kumar, R., and Krumpelt, M., 1994, “Development of a Catalytic Partial Oxidation Reformer for Methanol Used in Fuel Cell Propulsion Systems,” Fuel Cell Seminar, November 28-December 1, San Diego, CA, Program and Abstracts.
2.
Amphlett, J. C., Mann, R. F., Peppley, B. A., and Stokes, D. M., 1991, “Some Design Considerations for a Catalytic Methanol Steam Reformer for a PEM Fuel Cell Power Generating System,” The 26th Intersociety Energy Conversion Engineering Conference (3), Proceedings, pp. 642–649.
3.
Geyer, H. K., Ahluwalia, R., Krumpelt, M., and Kumar, R., 1994, “Transportation Polymer Electrolyte Fuel Cell Systems for Different On-Board Fuels,” Fuel Cell Seminar, November 28-December 1, San Diego, CA, Program and Abstracts.
4.
Helms, H. E., and Haley, P. J., 1992, “Development of a PEM Fuel Cell System for Vehicular Application,” Society of Automotive Engineers Paper No. 921541.
5.
Loftus, P., Thijssen, J., Bentley, J., Bowman, J., 1994, “Development of a Multi-Fuel Partial Oxidation Reformer for Transportation Applications,” Fuel Cell Seminar, November 28-December 1, San Diego, CA, Program and Abstracts.
6.
Ohl, G., 1995, “Dynamic Analyses of a Methanol to Hydrogen Steam Reformer for Transportation Applications,” Ph.D. thesis, University of Michigan, Ann Arbor, MI, Apr.
7.
Ohl, G., Stein, J., and Smith, G., 1995, “A Dynamic Model for the Design of Methanol to Hydrogen Steam Reformers for Transportation Applications,” submitted for review for the JOURNAL OF ENERGY RESOURCES TECHNOLOGY.
8.
Santacesaria
E.
, and
Carra
S.
,
1983
, “
Kinetics of Catalytic Steam Reforming of Methanol in a CSTR Reactor
,”
Applied Catalysis
, Vol.
5
, pp.
345
358
.
9.
The´rien
N.
, and
Tessier
P.
,
1987
, “
Modeling and Simulation of the Catalytic Decomposition of Methanol in a Fixed Bed Reactor (in French)
Canadian Journal of Chemical Engineering
, Vol.
65
, Dec., pp.
950
957
.
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