Supplementing Electric Utility Power
With Fuel Cells in Brazil

Acoustic Fields Enrich Hydrogen Production by Reformers

Fuel-cell powered electric vehicles need hydrogen refueling, which can be provided by specially constructed “service stations” in cities. These stations can be supplied hydrogen from underground piping or from tank trucks. The stations might even manufacture hydrogen with electrolyzers. However, these hydrogen resources might not be available in remote areas. Also, a hydrogen-powered electric vehicle might be stranded in a remote area, with no way of getting hydrogen. Paul Erickson had evaluated for these applications the possibility of a practical steam reformer for generating hydrogen (2).

Reforming hydrocarbons is today’s principal process for producing the commercial hydrogen used to cool big generators in power plants or propel the boosters that launch spacecraft. Preheated hydrocarbons are mixed with steam and passed over a nickel catalyst at temperatures ranging from 649EC to 982EC, producing carbon dioxide and hydrogen. In the steam-iron process, hydrogen is produced by reacting steam at high temperature over reduced iron oxide to give hydrogen. Then a reducing gas, such as water gas or producer gas, is used to re-reduce the iron oxide, so it can be used again.

Erickson investigated the possibility of enhancing reformation processes through superposition of an acoustic field in the catalyst bed of a steam reformer. Proven acoustic enhancement of various processes was reviewed, and the theory of steam-reforming process was developed. Relevant parameters of the acoustic field were quantified.

Although the facility used has not been optimized for utilizing acoustic waves, significant acoustic enhancement of the steam-reformation process was demonstrated, and acoustic enhancements showed a positive effect on the steam reforming. Results included increased reactor capacity for a given size and mass, smoothing the temperature profile, and better control of the temperatures in the catalyst bed. Erickson expected similar results for other fuels and reforming methods.

References

The following papers are published in the “Proceedings of the 37th Intersociety Energy Conversion Engineering Conference,” held July 29-31, 2002, which carries IEEE Catalog Number 02CH37298, and Library of Congress Number 2001096634. Copies of the Proceedings or of individual papers can be procured from the Institute of Electrical and Electronics Engineers, IEEE Operations Center, P. O.Box 1331, Piscataway, NJ 08855-1331.

1. Canha, Luciane Neves and Associates, “Optimal Characteristics of Fuel Cell Generating Systems for Utility Distribution Networks,” IECEC 2002 paper 20060.

2. Erickson, Paul A., “Enhancing Hydrogen Production for Fuel Cell Vehicles by Superposition of Acoustic Fields on the Reformer. A Preliminary Study” (Not in Proceedings of 37th IECEC.)