Diesel reforming for SOFC auxiliary power units
- Rodney L.
- Michael A.
- Jose I.
- Dennis Ray
The use of a solid-oxide fuel cell (SOFC) to provide auxiliary power for heavy duty trucks can increase fuel efficiency and reduce emissions by reducing engine idling time. The logical fuel of choice for a truck SOFC APU is diesel fuel, as diesel is the fuel of choice for these vehicles. SOFC's that directly oxidize hydrocarbon fuels have lower power densities than do SOFC's that operate from hydrocarbon reformate, and since the SOFC is a costly component, maximizing the fuel cell power density provides benefits in reducing the overall APU system cost. Thus current SOFC APU systems require the reformation of higher hydrocarbons for the most efficient and cost effect fuel cell system. The objective of this research is to develop the technology to enable diesel reforming for SOFC truck APU applications. Diesel fuel can be reformed into a H{sub 2} and CO-rich fuel feed stream for a SOFC by autothermal reforming (ATR), a combination of catalytic partial oxidation (CPOx), and steam reforming (SR). The typical autothermal reformer is an adiabatic, heterogeneous catalytic reactor and the challenges in its design, operation and durability on diesel fuel are manifold. These challenges begin with the vaporization and mixing of diesel fuel with air and steam where fuel pyrolysis can occur and improper mixing leads to hot and cold spots, which contribute to carbon formation and incomplete fuel conversion. The exotherm of the partial oxidation reaction can generate temperatures in excess of 800 C, a temperature at which catalysts rapidly sinter, thus reducing their lifetime. The temperature rise can be reduced by the steam reforming endotherm, but this requires the addition of water along with proper design to balance the kinetic rates. Carbon formation during operation and startup can lead to catalyst deactivation and fouling of downstream components, thus reducing durability of the fuel processor. Water addition helps to reduce carbon formation, but a key issue is the source of the water onboard a vehicle. Additionally, changes in diesel fuel composition, such as seasonal changes affect the reactor operation and design considerations. Our research addresses these issues through an experimental and modeling examination of the fundamentals of these processes.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 977793
- Report Number(s):
- LA-UR-04-5370; TRN: US201012%%730
- Resource Relation:
- Conference: Submitted to: Fuel Cell Seminar, November 2004, San Antonio, TX
- Country of Publication:
- United States
- Language:
- English
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