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.

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

2008 ◽  
Vol 130 (2) ◽  
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 250kW 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 0–180deg 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 steam to carbon ratio 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 toward null values.

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.

Performance Analysis of Solid Oxide Fuel Cell Stack: Part 1 — Model Description and Validation

2007 ◽  
Author(s):  
Vittorio Verda ◽  
Michele Cali`
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Solid Oxide ◽  
Model Description ◽  
Current Transfer ◽  
Oxide Fuel ◽  
Cfd Model ◽  
Detailed Model ◽  
Fuel Cell Stack ◽  
Stack Model

In this paper a detailed model for the simulation of a tubular solid oxide fuel cell stack is presented. The model solves heat transfer, current transfer and fluid flow in the stack. The effect of mass transfer is accounted by means of the information provided by a CFD model of a single cell. The approach used to build the model allows one to simulate large stacks, predicting the temperature, current and mass flow rate profiles. The model has been applied to the CHP100 manufactured by Siemens. The results obtained by the stack model are compared with some of the available measurements.

Novel Electrode-Supported Honeycomb Solid Oxide Fuel Cell: Design and Fabrication

2010 ◽  
Vol 7 (4) ◽  
Author(s):  
Toshiaki Yamaguchi ◽  
Toshio Suzuki ◽  
Yoshinobu Fujishiro ◽  
Masanobu Awano ◽  
Sota Shimizu
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Honeycomb Structure ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Current Collection ◽  
Fuel Flow ◽  
Space Saving ◽  
Channel Surface ◽  
Calculation Results

We have developed a novel and highly effective electrode-supported solid oxide fuel cell (SOFC) with honeycomb structure for intermediate temperature operation. Honeycomb-supported SOFC is known as one of the most compact SOFCs due to the large electrode area per unit volume, which is attractive with regard to space saving and cost reduction. In this study, we summarized the design of the channel shape, size, and sequence using numerical simulation and technologies to realize the designed honeycomb SOFC fabrication. The calculation results showed that the wall thickness and the channel size of the honeycomb had to be less than 0.22 mm and more than 0.3 mm, respectively, for the sufficient net channel surface and the acceptable pressure drop. Also, a cathode-honeycomb-supported SOFC can be the more efficient form with lower current collection resistance, as compared with the anode-supported type. The actual fabricated honeycomb SOFC exhibited a high volumetric power density above 1 W/cm3 at 650°C under wet H2 fuel flow.

Influence of fuel flow rate on the performance of micro tubular solid oxide fuel cell

2020 ◽  
Vol 45 (24) ◽  
pp. 13459-13468 ◽  
Author(s):  
Daan Cui ◽  
Yulong Ji ◽  
Chao Chang ◽  
Zhe Wang ◽  
Xiu Xiao
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Flow Rate ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fuel Flow Rate ◽  
Fuel Flow

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 Multiphysics Field Distribution Characteristics within the One-Cell Solid Oxide Fuel Cell Stack with Typical Interdigitated Flow Channels

2019 ◽  
Vol 9 (6) ◽  
pp. 1190 ◽  
Author(s):  
Yu Xu ◽  
Anton Kukolin ◽  
Daifen Chen ◽  
Wei Yang
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Air Flow ◽  
Flow Path ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Distribution Characteristics ◽  
Fuel Flow ◽  
Flow Channels ◽  
Line Type

Generally, the manufacturing technology of fuel cell units is considered to satisfy the current commercialization requirements. However, achieving a high-performance and durable stack design is still an obstacle in its commercialization. The solid oxide fuel cell (SOFC) stack is considered to have performance characteristics that are distinct from the proton exchange membrane fuel cell (PEMFC) stacks. Within the SOFC stack, vapor is produced on the anode side instead of the cathode side and high flow resistance within the fuel flow path is recommended. In this paper, a 3D multiphysics model for a one-cell SOFC stack with the interdigitated channels for fuel flow path and conventional paralleled line-type rib channels for air flow path is firstly developed to predict the multiphysics distribution details. The model consists of all the stack components and couples well the momentum, species, and energy conservation and the quasi-electrochemical equations. Through the developed model, we can get the working details within those SOFC stacks with the above interdigitated flow channel features, such as the fuel and air flow feeding qualities over the electrode surface, hydrogen and oxygen concentration distributions within the porous electrodes, temperature gradient distribution characteristics, and so on. The simulated result shows that the multiphysics field distribution characteristics within the SOFC and PEMFC stacks with interdigitated flow channels feature could be very different. The SOFC stack using the paralleled line-type rib channels for air flow path and adopting the interdigitated flow channels for the fuel flow path can be expected to have good collaborative performances in the multiphysics field. This design would have good potential application after being experimentally confirmed.

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.

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