Abstract:
Fuel cells that utilize hydrogen are promising energy
conversion units that have a high intrinsic efficiency. However
there are operational difficulties in storing hydrogen. One way
to alleviate this problem is to generate hydrogen in situ from a
liquid fuel such as ethanol in a reformer. In this paper, an
ethanol reformer was modeled as a tubular non-isothermal,
non-isobaric packed-bed reactor with an annular heat transfer
jacket, operating at unsteady state. Since the reforming reaction
is endothermic, it is necessary to design a suitable heat transfer
jacket to provide heat to the reformer. The partial differential
equations of the reformer model were solved numerically after
estimating the model parameters from the literature. The effect
of inlet conditions on the heat transfer characteristics were
studied. Model predictions of hydrogen generation were
compared to experimental data available in the literature for a
laboratory-scale reformer and were shown to be in excellent
agreement. A commercial-scale reformer was designed using
this high-fidelity model that can produce sufficient hydrogen to
generate up to 5 kW of power when used in conjunction with a
Ballard Mark V fuel-cell stack. Experimental data from the
dynamic power consumption in a 3-bedroom house were used
to determine the size of the reformer as well as a back-up
battery that supplies power when the reformer is unable to meet
the power demand.
Description:
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.
