Effects of Methane Pre-Reforming Percentage and Flow Arrangement on the Distribution of Temperature and Thermal Stress in Solid Oxide Fuel Cell

Abstract

To obtain detailed information on the temperature field and thermal stress field inside the solid oxide fuel cell (SOFC) fueled with partially pre-reformed methane. A three-dimensional geometric and mathematical model of the SOFC is implemented by using the finite element method in the commercial software COMSOL Multiphysics®. The coupling characteristics were analyzed for electrode chemical reaction, multi-component mass transfer, and heat transfer process under typical operating conditions, which was further applied for predicting and analyzing the thermal stress distribution. After model validation, parametric simulations are conducted to investigate how the methane pre-reforming percentage and flow arrangement affect the temperature and the thermal stress of SOFC. The simulated results show that reducing the methane pre-reforming percentages can decrease the temperature maximum and the variation range of the first principal stress, but will increase the possibility of carbon deposition. The maximum temperature of the counter-flow is about 20 K lower than that of the co-flow, and the first principal stress variation range of the counter-flow is 8.6 Mpa lower than that of the co-flow. The methane pre-reforming percentages have a significant effect on the heat transfer and the thermal stress, and the counter-flow can improve the temperature uniformity and reduce the thermal stress variation range.

Thermo-Electro-Chemo-Mechanical Coupled Modeling of Solid Oxide Fuel Cell with LSCF-GDC Composite Cathode

“…The heat is generated by the charged-species (oxygen ions and electrons) transport, activation polarization, and exothermic electrochemical reaction. The heat generated is predominantly conducted through metallic ribs owing to their large thermal conductivity [ 27 ], and the heat is in turn transported to the inlet gases carried by them. It is also noted that there is a significant temperature difference between the cell and the outside environment, which also causes some of the heat to be radiated from the outer walls through electromagnetic waves [ 23 ].…”

“…The charge transfer mainly includes the transfer of electrons in the conductor and the transfer of oxygen ions in the electrolyte material. The ion and electron conservation can be expressed as [ 27 ]: where σ ion,eff and σ elec,eff are the ionic conductivity and electrical conductivity, respectively, i is the current density, and A ve is the specific surface area.…”

“…From the literature research above, it is clear that no detailed thermo-electro-chemo-mechanical analysis of SOFC with LSCF-GDC composite cathode fueled by methanol syngas was conducted. Given that simultaneous thermal/mechanical solid-gas interactions and thermal-electrochemical-chemical reactions occur between the porous electrode surface and the gas species inside the SOFC, a three-dimensional numerical model from the previous research [ 27 ] is extended to elucidate the physical-chemical phenomena occurring in a planar SOFC with LSCF-GDC composite cathode. This study presents a modeling framework that combines thermo-electro-chemo models (including the methanol conversion process and the H 2 -H 2 O and CO-CO 2 electrochemical reactions) and a contact thermo-mechanical model that considers the effective mechanical properties of composite material.…”

Coupled Electrochemical-Thermo-Stress Analysis for Methanol-Fueled Solid Oxide Fuel Cells

“…Additionally, they found that higher inlet temperatures not only increased power output but also improved the uniformity of the cell temperature distribution. Cai et al 16 constructed a contact thermomechanical model considering the effective mechanical properties of composite electrode materials using finite element software. They investigated the impact of inlet fuel types (hydrogen, methanol syngas) and flow arrangements (co-flow, counter-flow) on performance indicators of the cell, such as high-temperature zones, current density, and maximum thermal stress.…”