Key characteristics of a hydrocarbon-fueled solid oxide fuel cell examined by local thermodynamic states

Title
Key characteristics of a hydrocarbon-fueled solid oxide fuel cell examined by local thermodynamic states
Authors
이종호윤경중이상혁배용균최원준홍종섭
Keywords
SOFC; Internal reforming; Thermochemistry; Heat and mass transfer
Issue Date
2018-10
Publisher
Energy conversion and management
Citation
VOL 174-578
Abstract
Key features of hydrocarbon-fueled solid oxide fuel cell stack operation are elucidated by examining its local thermodynamic states with an aid of three-dimensional numerical simulations. A high-fidelity physical model, which resolves the coupling between thermo-chemical reactions and heat and mass transport, is developed and validated. To elucidate important reactions and transport phenomena, local thermodynamic state variables of hydrocarbon-fueled operation are compared with those estimated by assuming pure-hydrogen-supplied operation. Results show that thermochemical reactions proceed at high rates through the thick anode support layer. This induces complete methane conversion as soon as it is introduced to the anode and thermochemical reaction zones concentrated in the vicinity of the fuel inlet. In spite of the fast reaction processes, hydrocarbon-fueled operation has the same electrical current density profile as pure-hydrogen-supplied operation, resulting from changing its local thermodynamic states. Given that the presence of carbon substances and thermochemical reactions, in hydrocarbon-fueled operation, local chemical and electrical conditions are substantially different from those of pure-hydrogen-supplied operation. A lower hydrogen concentration induces a higher concentration overpotential and decreases a reversible electrochemical potential. A lower exchange current density is offset by increasing an activation overpotential at a given applied current. All these reduce the overall cell voltage, as compared to pure-hydrogen-supplied operation. Variation of transport properties such as diffusivities and viscosities influences heat and mass transport such that substantial stresses can be imposed on cell materials. In addition, thermal conditions result in lower incoming-gas heating and a larger heat transfer rate to a neighboring repeating unit. A larger temperature gradient near the fuel inlet may also i
URI
http://pubs.kist.re.kr/handle/201004/68029
ISSN
0196-8904
Appears in Collections:
KIST Publication > Article
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE