scholarly journals Dynamic Simulation of an Integrated Solid Oxide Fuel Cell System Including Current-Based Fuel Flow Control

2005 ◽  
Vol 3 (2) ◽  
pp. 144-154 ◽  
Author(s):  
Fabian Mueller ◽  
Jacob Brouwer ◽  
Faryar Jabbari ◽  
Scott Samuelsen
Keyword(s):  
Fuel Cell ◽  
Flow Control ◽  
Solid Oxide Fuel Cell ◽  
Hydrogen Concentration ◽  
Characteristic Temperature ◽  
Solid Oxide ◽  
Dynamic Responses ◽  
Oxide Fuel ◽  
Fuel Flow ◽  
The Impact

A two-dimensional dynamic model was created for a Siemens Westinghouse type tubular solid oxide fuel cell (SOFC). This SOFC model was integrated with simulation modules for other system components (e.g., reformer, combustion chamber, and dissipater) to comprise a system model that can simulate an integrated 25kw SOFC system located at the University of California, Irvine. A comparison of steady-state model results to data suggests that the integrated model can well predict actual system power performance to within 3%, and temperature to within 5%. In addition, the model predictions well characterize observed voltage and temperature transients that are representative of tubular SOFC system performance. The characteristic voltage transient due to changes in SOFC hydrogen concentration has a time scale that is shown to be on the order of seconds while the characteristic temperature transient is on the order of hours. Voltage transients due to hydrogen concentration change are investigated in detail. Particularly, the results reinforce the importance of maintaining fuel utilization during transient operation. The model is shown to be a useful tool for investigating the impacts of component response characteristics on overall system dynamic performance. Current-based flow control (CBFC), a control strategy of changing the fuel flow rate in proportion to the fuel cell current is tested and shown to be highly effective. The results further demonstrate the impact of fuel flow delay that may result from slow dynamic responses of control valves, and that such flow delays impose major limitations on the system transient response capability.

scholarly journals Dynamic Simulation of an Integrated Solid Oxide Fuel Cell System Including Current-Based Fuel Flow Control

2005 ◽  
Author(s):  
Fabian Mueller ◽  
Jacob Brouwer ◽  
Faryar Jabbari ◽  
Scott Samuelsen
Keyword(s):  
Fuel Cell ◽  
Flow Control ◽  
Solid Oxide Fuel Cell ◽  
Hydrogen Concentration ◽  
Characteristic Temperature ◽  
Solid Oxide ◽  
Dynamic Responses ◽  
Oxide Fuel ◽  
Fuel Flow ◽  
The Impact

A two-dimensional dynamic model was created for a Siemens Westinghouse type tubular solid oxide fuel cell (SOFC). This SOFC model was integrated with simulation modules for other system components (e.g., reformer, combustion chamber, and dissipater) to comprise a system model that can simulate an integrated 25 kilowatt SOFC system located at the University of California, Irvine. A comparison of steady-state model results to data suggests that the integrated model can well predict actual system power performance to within 3 percent, and temperature to within 5 percent. In addition, the model predictions well characterize observed voltage and temperature transients that are representative of tubular SOFC system performance. The characteristic voltage transient due to changes in SOFC hydrogen concentration has a time scale that is shown to be on the order of seconds while the characteristic temperature transient is on the order of hours. Voltage transients due to hydrogen concentration change are investigated in detail. Particularly, the results reinforce the importance of maintaining fuel utilization during transient operation. The model is shown to be a useful tool for investigating the impacts of component response characteristics on overall system dynamic performance. Current-based flow control (CBFC), a control strategy of changing the fuel flow rate in proportion to the fuel cell current is tested and shown to be highly effective. The results further demonstrate the impact of fuel flow delay that may result from slow dynamic responses of control valves, and that such flow delays impose major limitations on the system transient response capability.

Time Characterisation of the Anodic Loop of a Pressurized Solid Oxide Fuel Cell System

2007 ◽  
Author(s):  
A. Traverso ◽  
F. Trasino ◽  
L. Magistri ◽  
A. F. Massardo
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Frequency Analysis ◽  
Solid Oxide ◽  
Model Description ◽  
Oxide Fuel ◽  
Realistic Case ◽  
Threshold Frequency ◽  
Fuel Flow ◽  
First Case

A dynamic Solid Oxide Fuel Cell (SOFC) model was integrated with other system components (i.e.: reformer, anodic off-gas burner, anodic ejector) to build a system model that can simulate the time response of the anode side of an integrated 250 kW pressurized SOFC hybrid system. After model description and data on previous validation work, this paper describes the results obtained for the dynamic analysis of the anodic loop, taking into account two different conditions for the fuel flow input: in the first Case (I), the fuel flow follows with no delay the value provided by the control system, while in the second Case (II) the flow is delayed by a volume between the regulating valve and the anode ejector, this being a more realistic case. The step analysis was used to obtain information about the time scales of the investigated phenomena: such characteristic times were successfully correlated to the results of the subsequent frequency analysis. This is expected to provide useful indications for designing robust anodic loop controllers. In the frequency analysis, most phase values remained in the 0–180° range, thus showing the expected delay-dominated behavior in the anodic loop response to the input variations in the fuel and current. In Case I, a threshold frequency of 5Hz for the pressure and STCR, and a threshold frequency of 31Hz for the anodic flow were obtained. In the more realistic Case II, natural gas pipe delay dominates, and a threshold frequency of 1.2Hz was identified, after which property oscillations start to decrease towards null values.

Solid Oxide Fuel Cell System and the Economical Feasibility

2006 ◽  
Vol 3 (3) ◽  
pp. 242-253 ◽  
Author(s):  
Erkko Fontell ◽  
Tho Phan ◽  
Timo Kivisaari ◽  
Kimmo Keränen
Keyword(s):  
Fuel Cell ◽  
Natural Gas ◽  
Solid Oxide Fuel Cell ◽  
Cell System ◽  
Solid Oxide ◽  
Maintenance Cost ◽  
Oxide Fuel ◽  
Market Conditions ◽  
The Impact ◽  
Economical Feasibility

In the paper, a solid oxide fuel cell (SOFC) system is briefly described and its economical feasibility in three different applications is analyzed. In the feasibility analysis, the SOFC system is part of commercial applications where energy is used for power and heat generation. In the economical analysis, the three applications have different load profiles which are studied separately at different geographical locations with associated local energy market conditions. The price for natural gas and electricity varies by location, leading to a different feasibility condition for stationary fuel cell application as well as for other distributed generation equipment. In the study, the spark spread of natural gas and electricity is used as a base variable for the analysis. The feasibility is analyzed in the case of an electricity-only application as well as with two combined heat and power applications, where an economical value is assigned to the produced and consumed heat. The impact on economical competitiveness of possible incentives for the generated fuel cell power is estimated. A sensitivity analysis with different fuel cell-units’ electrical efficiency, maintenance cost, and payback period is presented. Finally, the maximum allowed investment cost levels for the SOFC system at different locations and market conditions is presented.

The impact of sulfur on the performance of a solid oxide fuel cell (SOFC) system operated with hydrocarboneous fuel gas

2009 ◽  
Vol 189 (2) ◽  
pp. 1127-1131 ◽  
Author(s):  
Florian P. Nagel ◽  
Tilman J. Schildhauer ◽  
Josef Sfeir ◽  
Alexander Schuler ◽  
Serge M.A. Biollaz
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fuel Gas ◽  
The Impact

Modelling the impact of creep on the probability of failure of a solid oxide fuel cell stack

2014 ◽  
Vol 34 (11) ◽  
pp. 2695-2704 ◽  
Author(s):  
Fabio Greco ◽  
Henrik Lund Frandsen ◽  
Arata Nakajo ◽  
Mads Find Madsen ◽  
Jan Van herle
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Probability Of Failure ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fuel Cell Stack ◽  
The Impact

Performance Evaluation of Solid Oxide Fuel Cell Engines Integrated With Single/Dual-Spool Turbochargers

2011 ◽  
Vol 8 (6) ◽  
Author(s):  
So-Ryeok Oh ◽  
Jing Sun ◽  
Herb Dobbs ◽  
Joel King
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Control Strategies ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Operating Characteristics ◽  
Load Following ◽  
Fuel Flow

This study investigates the performance and operating characteristics of 5kW-class solid oxide fuel cell and gas turbine (SOFC/GT) hybrid systems for two different configurations, namely single- and dual- spool gas turbines. Both single and dual spool turbo-chargers are widely used in the gas turbine industry. Even though their operation is based on the same physical principles, their performance characteristics and operation parameters vary considerably due to different designs. The implications of the differences on the performance of the hybrid SOFC/GT have not been discussed in literature, and will be the topic of this paper. Operating envelops of single and dual shaft systems are identified and compared. Performance in terms of system efficiency and load following is analyzed. Sensitivities of key variables such as power, SOFC temperature, and GT shaft speed to the control inputs (namely, fuel flow, SOFC current, generator load) are characterized, all in an attempt to gain insights on the design implication for the single and dual shaft SOFC/GT systems. Dynamic analysis are also performed for part load operation and load transitions, which shed lights for the development of safe and optimal control strategies.

scholarly journals The impact of NiO on microstructure and electrical property of solid oxide fuel cell anode

2005 ◽  
Vol 6B (11) ◽  
pp. 1124-1129 ◽  
Author(s):  
Yan Li ◽  
Zhong-yang Luo ◽  
Chun-jiang Yu ◽  
Dan Luo ◽  
Zhu-an Xu ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Electrical Property ◽  
Solid Oxide Fuel Cell ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Cell Anode ◽  
Fuel Cell Anode ◽  
The Impact

Hardware-Based Simulation of a Fuel Cell Turbine Hybrid Response to Imposed Fuel Cell Load Transients

2006 ◽  
Author(s):  
Thomas P. Smith ◽  
Comas L. Haynes ◽  
William J. Wepfer ◽  
David Tucker ◽  
Eric A. Liese
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Pressure Vessels ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Electrical Load ◽  
Fuel Cell Stack ◽  
Thermal Transients ◽  
The Impact

Electrical load transients imposed on the cell stack of a solid oxide fuel cell/gas turbine hybrid power system are studied using the Hybrid Performance (HyPer) project. The hardware simulation facility is located at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). A computational fuel cell model capable of operating in real time is integrated with operating gas turbine hardware. The thermal output of a modeled 350 kW solid oxide fuel cell stack is replicated in the facility by a natural gas fired burner in a direct fired hybrid configuration. Pressure vessels are used to represent a fuel cell stack's cathode flow and post combustion volume and flow impedance. This hardware is used to simulate the fuel cell stack and is incorporated with a modified turbine, compressor, and 120 kW generator on a single shaft. For this study, a simulation was started with a simulated current demand of 307 A on the fuel cell at approximately 0.75 V and an actual 45 kW electrical load on the gas turbine. An open loop response, allowing the turbine rotational speed to respond to thermal transients, was successfully evaluated for a 5% current reduction on the fuel cell followed by a 5% current increase. The impact of the fuel cell load change on system process variables is presented. The test results demonstrate the capabilities of the hardware-in-the-loop simulation approach in evaluating hybrid fuel cell turbine dynamics and performance.

Cfd Analysis of Heat Transfer in a Microtubular Solid Oxide Fuel Cell Stack

2014 ◽  
Vol 35 (3) ◽  
pp. 293-304 ◽  
Author(s):  
Paulina Pianko-Oprych ◽  
Ekaterina Kasilova, ◽  
Zdzisław Jaworski
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Heat Losses ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Reaction Heat ◽  
Flux Profile ◽  
The Impact

Abstract The aim of this work was to achieve a deeper understanding of the heat transfer in a microtubular Solid Oxide Fuel Cell (mSOFC) stack based on the results obtained by means of a Computational Fluid Dynamics tool. Stack performance predictions were based on simulations for a 16 anodesupported mSOFCs sub-stack, which was a component of the overall stack containing 64 fuel cells. The emphasis of the paper was put on steady-state modelling, which enabled identification of heat transfer between the fuel cells and air flow cooling the stack and estimation of the influence of stack heat losses. Analysis of processes for different heat losses and the impact of the mSOFC reaction heat flux profile on the temperature distribution in the mSOFC stack were carried out. Both radiative and convective heat transfer were taken into account in the analysis. Two different levels of the inlet air velocity and three different values of the heat losses were considered. Good agreement of the CFD model results with experimental data allowed to predict the operation trends, which will be a reliable tool for optimisation of the working setup and ensure sufficient cooling of the mSOFC stack.

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