Fuel processing for PEM fuel cells: transport and kinetic issues
of system design
Journal of Power Sources, 111 (1):
58-64 (2002/9/18 2002)TY - JOUR.Abstract
In light of the distribution and storage issues associated with hydrogen,
efficient on-board fuel processing will be a significant factor in
the implementation of PEM fuel cells for automotive applications.
Here, we apply basic chemical engineering principles to gain insight
into the factors that limit performance in each component of a fuel
processor. A system consisting of a plate reactor steam reformer,
water-gas shift unit, and preferential oxidation reactor is used
as a case study. It is found that for a steam reformer based on catalyst-coated
foils, mass transfer from the bulk gas to the catalyst surface is
the limiting process. The water-gas shift reactor is expected to
be the largest component of the fuel processor and is limited by
intrinsic catalyst activity, while a successful preferential oxidation
unit depends on strict temperature control in order to minimize parasitic
hydrogen oxidation. This stepwise approach of sequentially eliminating
rate-limiting processes can be used to identify possible means of
performance enhancement in a broad range of applications.