Control Sensitivity Study for a Hybrid Fuel Cell/Gas Turbine System

2008 ◽  
Author(s):  
Larry Banta ◽  
Jason Absten ◽  
Alex Tsai ◽  
Randall Gemmen ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Air Flow ◽  
Sensitivity Study ◽  
Test Methods ◽  
System Control ◽  
Control Mechanisms ◽  
Operating Characteristics ◽  
Efficient Operation

The National Energy Technology Laboratory (NETL) has developed a hardware simulator to test the operating characteristics of Solid Oxide Fuel Cell/Gas Turbine (SOFC/GT) hybrid systems. The Hybrid Performance (HyPer) simulator has been described previously, and has contributed to the understanding of SOFC/GT system operation. HyPer contains not only the requisite elements of gas turbine/compressor/generator, recuperator, combustor, and associated piping, but also several air flow control valves that are proposed as system control mechanisms. It is necessary to know how operation of these valves affects the various entities such as cathode air flow, turbine speed, and various temperatures important to the safe and efficient operation of fuel cell/gas turbine hybrid systems. To determine the interactions among key variables, a series of experiments was performed in which the effect of modulating each of the key manipulated variables was recorded. This document outlines the test methods used and presents some of the data from those tests, along with analysis and interpretation of that data in the context of control system design.

scholarly journals A Real-Time Degradation Model for Hardware in the Loop Simulation of Fuel Cell Gas Turbine Hybrid Systems

2015 ◽  
Author(s):  
Valentina Zaccaria ◽  
Alberto Traverso ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Current Density ◽  
Gas Turbines ◽  
Hardware In The Loop ◽  
Fuel Utilization ◽  
Time Operation ◽  
The Impact

The theoretical efficiencies of gas turbine fuel cell hybrid systems make them an ideal technology for the future. Hybrid systems focus on maximizing the utilization of existing energy technologies by combining them. However, one pervasive limitation that prevents the commercialization of such systems is the relatively short lifetime of fuel cells, which is due in part to several degradation mechanisms. In order to improve the lifetime of hybrid systems and to examine long-term stability, a study was conducted to analyze the effects of electrochemical degradation in a solid oxide fuel cell (SOFC) model. The SOFC model was developed for hardware-in-the-loop simulation with the constraint of real-time operation for coupling with turbomachinery and other system components. To minimize the computational burden, algebraic functions were fit to empirical relationships between degradation and key process variables: current density, fuel utilization, and temperature. Previous simulations showed that the coupling of gas turbines and SOFCs could reduce the impact of degradation as a result of lower fuel utilization and more flexible current demands. To improve the analytical capability of the model, degradation was incorporated on a distributed basis to identify localized effects and more accurately assess potential failure mechanisms. For syngas fueled systems, the results showed that current density shifted to underutilized sections of the fuel cell as degradation progressed. Over-all, the time to failure was increased, but the temperature difference along cell was increased to unacceptable levels, which could not be determined from the previous approach.

Cycle analysis of solid oxide fuel cell-gas turbine hybrid systems integrated ethanol steam reformer: Energy management

Energy ◽  
2017 ◽  
Vol 127 ◽  
pp. 743-755 ◽  
Author(s):  
Dang Saebea ◽  
Loredana Magistri ◽  
Aristide Massardo ◽  
Amornchai Arpornwichanop
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Energy Management ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Steam Reformer ◽  
Ethanol Steam

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 Development of a Dynamic Cathode Ejector Model for Solid Oxide Fuel Cell-Gas Turbine Hybrid Systems

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
James D. Maclay ◽  
Jacob Brouwer ◽  
G. Scott Samuelsen
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Solid Oxide ◽  
Theoretical Development ◽  
Oxide Fuel ◽  
Simulink Model ◽  
Fuel Cell Cathode ◽  
Good Agreement

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems are attractive for future power generation with ultra-low criteria pollutant and greenhouse gas emissions. One of the challenges for SOFC-GT systems is to sufficiently pre-heat incoming air before it enters the fuel cell cathode. An ejector for cathode exhaust recirculation has the benefits of reliability, low maintenance, and cost compared to either recuperators or cathode recirculation blowers, which may be also be used for air pre-heating. In this study, a dynamic Simulink model of an ejector for cathode exhaust recirculation to pre-heat incoming fuel cell air has been developed. The ejector is to be utilized within a 100 MW SOFC-GT dynamic model operating on coal syngas. A thorough theoretical development is presented. Results for the ejector were found to be in good agreement with those reported in literature.

System Level Synthesis, Modeling and Roadmapping for Aeronautical SOFC/Gas Turbine Hybrid Systems

2005 ◽  
Author(s):  
Zhiwen Ma ◽  
Comas Haynes ◽  
Pinakin Patel
Keyword(s):  
Fuel Cell ◽  
Power Systems ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
System Modeling ◽  
Electrical Power ◽  
Cell System ◽  
System Level ◽  
Hybrid Power Systems ◽  
Auxiliary Power

Solid oxide fuel cell /gas turbine (SOFC/GT) hybrid power systems have been recognized as having the potential to operate at unprecedented levels of performance (e.g., 50%+ electrical power generation efficiencies with significantly mitigated greenhouse gas, criteria pollutant and noise emissions). Although the emphasis has been upon land applications, there are aeronautical benefits that may be derived as well. Despite these benefits, there have been limited investigations into the technical merit and feasibility of incorporating these hybrid systems onboard aerovehicles. A feasibility investigation has been performed in conjunction with fuel cell system modeling capabilities to conceptually establish auxiliary power system possibilities as well as the viability technology gaps.

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