A Simulation of the Solid Oxide Fuel Cell Electrochemical Light Off Phenomenon

2005 ◽  
Author(s):  
Comas L. Haynes ◽  
J. Chris Ford
Keyword(s):  
Fuel Cell ◽  
Thermal Cycling ◽  
Solid Oxide Fuel Cell ◽  
Heat Generation ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Cell Potential ◽  
Start Up ◽  
Electrochemical Transport

During latter-stage, “start-up” heating of a solid oxide fuel cell (SOFC) stack to a desired operating temperature, heat may be generated in an accelerating manner during the establishment of electrochemical reactions. This is because a temperature rise in the stack causes an acceleration of electrochemical transport given the typical Arrhenius nature of the electrolyte conductivity. Considering a potentiostatic condition (i.e., prescribed cell potential), symbiosis thus occurs because greater current prevalently leads to greater by-product heat generation, and vice versa. This interplay of the increasing heat generation and electrochemistry is termed “light off”, and an initial model has been developed to characterize this important thermal cycling phenomenon. The results of the simulation begin elucidating the prospect of using cell potential as well as other electrochemical operating conditions (e.g., reactants utilization) as dynamic controls in managing light off transients and possibly mitigating thermal cycling issues.

Analysis of Long-Term and Thermal Cycling Tests for a Commercial Solid Oxide Fuel Cell

2017 ◽  
Vol 14 (4) ◽  
Author(s):  
Dustin Lee ◽  
Jing-Kai Lin ◽  
Chun-Huang Tsai ◽  
Szu-Han Wu ◽  
Yung-Neng Cheng ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Thermal Cycling ◽  
Solid Oxide Fuel Cell ◽  
Coefficient Of Thermal Expansion ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Flow Rates ◽  
Degradation Rates ◽  
Two Stages

The effects of isothermally long-term and thermal cycling tests on the performance of an ASC type commercial solid oxide fuel cell (SOFC) have been investigated. For the long-term test, the cells were tested over 5000 h in two stages, the first 3000 h and the followed 2000 h, under the different flow rates of hydrogen and air. Regarding the thermal cycling test, 60 cycles in total were also divided into two sections, the temperature ranges of 700 °C to 250 °C and 700 °C to 50 °C were applied for the every single cycle of first 30 cycles and the later 30 cycles, respectively. The results of long-term test show that the average degradation rates for the cell in the first 3000 h and the followed 2000 h under different flow rates of fuel and air are 1.16 and 2.64%/kh, respectively. However, there is only a degradation of 6.6% in voltage for the cell after 60 thermal cycling tests. In addition, it is found that many pores formed in the anode of the cell which caused by the agglomeration of Ni after long-term test. In contrast, the vertical cracks penetrating through the cathode of the cell and the in-plane cracks between the cathode and barrier layer of the cell formed due to the coefficient of thermal expansion (CTE) mismatch after 60 thermal cycling tests.

Internal Reforming Solid Oxide Fuel Cell Gas Turbine Combined Cycles (IRSOFC-GT): Part B — Exergy and Thermoeconomic Analyses

2001 ◽  
Author(s):  
Aristide F. Massardo ◽  
Loredana Magistri
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Specific Work ◽  
Oxide Fuel ◽  
Internal Reforming ◽  
System Pressure ◽  
Combined Cycles

The aim of this work is to investigate the performance of Internal Reforming Solid Oxide Fuel Cell (IRSOFC) and Gas Turbine (GT) combined cycles. A mathematical model of the IRSOFC steady-state operation was presented in Part A of this work (Massardo and Lubelli, 1998), coupled to the thermodynamic analysis of a number of proposed IRSOFC-GT combined cycles, taking into account the influence of several technological constraints. In the second part of this work, both an exergy and a thermoeconomic analysis of the proposed cycles have been carried out using the TEMP code developed by the Author (Agazzani and Massardo, 1997). A suitable equation for IRSOFC cost evaluation based on cell geometry and performance has been proposed and employed to evaluate the electricity generation cost of the proposed combined systems. The results are presented and the influence of several parameters is discussed: external reformer operating conditions, fuel to air ratio, cell current density, compressor pressure ratio, etc. Diagrams proposed by the Author (Massardo and Scialo’, 2000) for cost vs. efficiency, cost vs. specific work, and cost vs. system pressure are also presented and discussed.

Performance Study of Hybrid Solid Oxide Fuel Cell–Gas Turbine Power System

2010 ◽  
Vol 171-172 ◽  
pp. 319-322
Author(s):  
Hong Bin Zhao ◽  
Xu Liu
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Cell Model ◽  
Research Work ◽  
Atmospheric Condition ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Oxide Fuel

The simulation and analyses of a “bottoming cycle” solid oxide fuel cell–gas turbine (SOFC–GT) hybrid system at the standard atmospheric condition is presented in this paper. The fuel cell model used in this research work is based on a tubular Siemens–Westinghouse–type SOFC with 1.8MW capacity. Energy and exergy analyses of the whole system at fixed conditions are carried out. Then, comparisons of the exergy destruction and exergy efficiency of each component are also conducted to determine the potential capability of the hybrid system to generate power. Moreover, the effects of operating conditions including fuel flow rate and SOFC operating temperature on performances of the hybrid system are analyzed.

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