Analysis of Electrochemical Performance and Exergy Loss in Solid Oxide Fuel Cell

2003 ◽  
Author(s):  
Kousuke Nishida ◽  
Toshimi Takagi ◽  
Shinichi Kinoshita
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
High Efficiency ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Exergy Loss ◽  
Oxide Fuel ◽  
Electrode Reactions ◽  
Exhaust Heat

A solid oxide fuel cell (SOFC) is expected to be applied to the distributed energy systems because of its high thermal efficiency and exhaust gas utilization. The exhaust heat from the SOFC can be transferred to the electric power by a gas turbine, and the high efficiency power generation can be achieved by constructing the SOFC and gas turbine hybrid system. In this study, the local processes in the electrodes and electrolyte of unit SOFC are analyzed taking into account the heat conduction, mass diffusion, electrode reactions and the transport of electron and oxygen ion. The temperature and concentration distributions perpendicular to the electrolyte membrane are shown. The effects of the operating conditions on the cell performance are also shown. Furthermore, the entropy generation and exergy loss of each process in the electrodes and electrolyte are analyzed and the reason for generating the exergy loss in the SOFC is clarified. It is noted that two electrode reactions are responsible for the major exergy loss.

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.

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

2002 ◽  
Vol 125 (1) ◽  
pp. 67-74 ◽  
Author(s):  
A. F. Massardo
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 I of this work 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. 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 for cost versus efficiency, cost versus specific work, and cost versus system pressure are also presented and discussed.

Investigating the Integration of a Solid Oxide Fuel Cell and a Gas Turbine System With Coal Gasification Technologies

2003 ◽  
Author(s):  
Dawson A. Plummer ◽  
Comas Haynes ◽  
William Wepfer
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Coal Gasification ◽  
High Efficiency ◽  
Integrated System ◽  
Solid Oxide ◽  
Operating Voltage ◽  
Oxide Fuel ◽  
Hybrid Power

Solid oxide fuel cell (SOFC) technology incorporates electrochemical reactions that generate electricity and high quality heat. The coupling of this technology with gas turbine bottoming cycles, to form hybrid power systems, leads to high efficiency levels. The purpose of this study is to conceptually integrate the hybrid power system with existing and imminent coal gasification technologies through computer simulation. The gasification technologies considered for integration include the Kellogg Brown Root (KBR) Transport Reactor and Entrained Coal Gasification. Parametric studies were performed to assess the effect of changes in pertinent fuel cell stack process settings such as operating voltage, inverse equivalence ratio and fuel utilization will be varied. Power output, system efficiency and costs are the chosen dependent variables of interest. Coal gasification data and a proven SOFC model program are used to test the theoretical integration. Feasibility and economic comparisons between the new integrated system and existing conventional systems are also made.

Designing Solid Oxide Fuel Cell Gas Turbine Hybrid Systems Using Exergy Analysis

2006 ◽  
Author(s):  
K. J. Bosch ◽  
N. Woudstra ◽  
K. V. van der Nat
Keyword(s):  
Fuel Cell ◽  
Natural Gas ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Exergy Analysis ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Exergy Losses

In conventional gas turbine systems combustion results in high exergy losses (∼30%) of fuel exergy input. Replacing the combustor with a high temperature fuel cell, like the Solid Oxide Fuel Cell (SOFC), will significantly reduce these exergy losses. As the SOFC electrochemically converts the natural gas, exergy losses are far lower (∼10%) compared to combustion. Natural gas entering a SOFC system has to be reformed first to hydrogen and carbon monoxide by steam reforming. Here it is chosen to use the heat generated by the fuel cell to drive the endothermic reforming reactions: internal reforming. The SOFC-GT system has the advantage that both fuel cell and gas turbine technology contribute to power production. In earlier work [1] several fuel cell system configurations with PEMFC, MCFC or SOFC, were analyzed studying the exergy flows. Here is focused on the SOFC-GT configuration, to get a detailed understanding of the exergy flows and losses through all individual components. Several configurations, combining the SOFC with the GT are possible. The selected operating conditions should prevent carbon deposition. Systems studies are performed to get more insight in the exergy losses in these combined systems. Exergy analysis facilitates the search for the high efficient SOFC-GT hybrid systems. Using exergy analysis, several useful configurations are found. Exergy losses are minimized by varying pressure ratio and turbine inlet temperature. Sensitivity studies, of equivalent cell resistance and fuel cell temperature, show that total system exergy efficiencies of more than 80% are conceivable, without using a bottoming cycle.

Hybrid Solid Oxide Fuel Cell/Gas Turbine System for High Altitude Long Endurance Aerospace Missions

2006 ◽  
Author(s):  
Ananda Himansu ◽  
Joshua E. Freeh ◽  
Christopher J. Steffen ◽  
Robert T. Tornabene ◽  
Xiao-Yen J. Wang
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
High Altitude ◽  
Gas Turbine ◽  
High Efficiency ◽  
Solid Oxide ◽  
Total System ◽  
Oxide Fuel ◽  
Solid Oxide Cell ◽  
Long Endurance

A system level analysis, inclusive of mass, is carried out for a cryogenic hydrogen fueled hybrid solid oxide fuel cell and bottoming gas turbine (SOFC/GT) power system. The system is designed to provide primary or secondary electrical power for an unmanned aerial vehicle (UAV) over a high altitude, long endurance mission. The net power level and altitude are parametrically varied to examine their effect on total system mass. Some of the more important technology parameters, including turbomachinery efficiencies and the SOFC area specific resistance, are also studied for their effect on total system mass. Finally, two different solid oxide cell designs are compared to show the importance of the individual solid oxide cell design on the overall system. We show that for long mission durations of 10 days or more, the fuel mass savings resulting from the high efficiency of an SOFC/GT system more than offset the larger powerplant mass resulting from the low specific power of the SOFC/GT system. These missions therefore favor high efficiency, low power density systems, characteristics typical of fuel cell systems in general.

Exergy Analysis of Photovoltaic Panels-Coupled Solid Oxide Fuel Cell and Gas Turbine-Electrolyzer Hybrid System

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Saber Sadeghi ◽  
Mehran Ameri
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Pareto Frontier ◽  
Optimization Method ◽  
Solid Oxide ◽  
Exergy Loss ◽  
Oxide Fuel ◽  
Points Of View

Exergy losses represent true losses of potential to generate a desired product, exergy efficiencies always provide a measure of approach to ideality, and the links between exergy and both economics and environmental impact can help develop improvements. In this study, PV-coupled Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT)-electrolyzer hybrid power generation system is considered to determine the contribution of different hybrid system components in the total exergy loss. The number of panels, the power of SOFC–GT, and the power of electrolyzer can have different values. Therefore, to obtain the optimum combination from ecological, economical, and reliability points of view, a multi-objective optimization algorithm (PESA) is considered. This optimization method chooses a set of optimum solutions that is known as Pareto frontier. The exergy loss of some of these optimum solutions is compared with each other. The effect of panel angle and SOFC–GT fuel type on the hybrid system exergy loss is considered in this study. Also, the hybrid system exergy loss is determined in different months of the year to obtain the worst month from exergy loss view.

Control Oriented Analysis of a Hybrid Solid Oxide Fuel Cell and Gas Turbine System

2009 ◽  
Vol 6 (4) ◽  
Author(s):  
Vasilis Tsourapas ◽  
Jing Sun ◽  
Anna Stefanopoulou
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
System Optimization ◽  
Open Loop ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Design System ◽  
Oxide Fuel ◽  
Fast Tracking

The goal of this work is to investigate the feasibility of a hybrid solid oxide fuel cell (SOFC) and gas turbine (GT) system for mobile power production. A system consisting of a gas turbine, a burner, and an SOFC is examined to gain fundamental understanding of the system dynamics. A control oriented dynamic model is developed to provide the critically needed tool for system feasibility analysis and control strategy design. System optimization and transient analysis are performed based on the system model to determine the desired operating conditions and load following limitations. It is shown that the open loop system will shut down in the case of a large load step. Based on the insights learned from the open loop analysis, a feedback control scheme is proposed. The feedback scheme is based on a reference governor, which modifies the load applied to the generator to guarantee stability and fast tracking during transients.

scholarly journals Dynamic Simulation of a Pressurized 220kW Solid Oxide Fuel-Cell–Gas-Turbine Hybrid System: Modeled Performance Compared to Measured Results

2005 ◽  
Vol 3 (1) ◽  
pp. 18-25 ◽  
Author(s):  
R. A. Roberts ◽  
J. Brouwer
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Dynamic Model ◽  
Hybrid System ◽  
High Efficiency ◽  
Large Range ◽  
Dynamic Performance ◽  
Solid Oxide ◽  
Oxide Fuel

Hybrid fuel-cell–gas-turbine (FC/GT) systems are technologically advanced systems that are promising for electric power generation with ultralow emissions and high efficiency for a large range of power plant sizes. A good understanding of the steady-state and dynamic performance of a FC/GT system is needed in order to develop and advance this hybrid technology. In this work, a detailed dynamic model of a solid oxide fuel cell/gas turbine (SOFC/GT) system has been developed. The system that is simulated represents the 220kW SOFC/GT hybrid system developed by Siemens Westinghouse. Results of the dynamic model and experimental data gathered during the operation and testing of the 220kW SOFC/GT at the National Fuel Cell Research Center are compared and presented.

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