A Degradation Diagnosis Method for Gas Turbine - Fuel Cell Hybrid Systems Using Bayesian Networks

2021 ◽  
Author(s):  
Luca Mantelli ◽  
Valentina Zaccaria ◽  
Mario L. Ferrari ◽  
Konstantinos G. Kyprianidis
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Bayesian Belief Network ◽  
Bayesian Belief Networks ◽  
Belief Networks ◽  
Essential Information ◽  
Belief Network ◽  
Starting Point

Abstract This paper aims to develop and test Bayesian belief network based diagnosis methods, which can be used to predict the most likely degradation levels of turbine, compressor and fuel cell in a hybrid system on the basis of different sensors measurements. The capability of the diagnosis systems to understand if an abnormal measurement is caused by a component degradation or by a sensor fault is also investigated. The data used both to train and to test the networks is generated from a deterministic model and later modified to consider noise or bias in the sensors. The application of Bayesian belief networks to fuel cell - gas turbine hybrid systems is novel, thus the results obtained from this analysis could be a significant starting point to understand their potential. The diagnosis systems developed for this work provide essential information regarding levels of degradation and presence of faults in gas turbine, fuel cell and sensors in a fuel cell - gas turbine hybrid system. The Bayesian belief networks proved to have a good level of accuracy for all the scenarios considered, regarding both steady state and transient operations. This analysis also suggests that in the future a Bayesian belief network could be integrated with the control system to achieve safer and more efficient operations of these plants.

A Degradation Diagnosis Method for Gas Turbine – Fuel Cell Hybrid Systems Using Bayesian Networks

2020 ◽  
Author(s):  
L. Mantelli ◽  
V. Zaccaria ◽  
K. Kyprianidis ◽  
M. L. Ferrari
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Cell Hybrid ◽  
Bayesian Belief Network ◽  
Bayesian Belief Networks ◽  
Belief Networks ◽  
Sensor Fault ◽  
Belief Network

Abstract During the last decades there has been a rise of awareness regarding the necessity to increase energy systems efficiency and reduce carbon emissions. These goals could be partially achieved through a greater use of gas turbine - solid oxide fuel cell hybrid systems to generate both electric power and heat. However, this kind of systems are known to be delicate, especially due to the fragility of the cell, which could be permanently damaged if its temperature and pressure levels exceed their operative limits. This could be caused by degradation of a component in the system (e.g. the turbomachinery), but also by some sensor fault which leads to a wrong control action. To be considered commercially competitive, these systems must guarantee high reliability and their maintenance costs must be minimized. Thus, it is necessary to integrate these plants with an automated diagnosis system capable to detect degradation levels of the many components (e.g. turbomachinery and fuel cell stack) in order to plan properly the maintenance operations, and also to recognize a sensor fault. This task can be very challenging due to the high complexity of the system and the interactions between its components. Another difficulty is related to the lack of sensors, which is common on commercial power plants, and makes harder the identification of faults in the system. This paper aims to develop and test Bayesian belief network based diagnosis methods, which can be used to predict the most likely degradation levels of turbine, compressor and fuel cell in a hybrid system on the basis of different sensors measurements. The capability of the diagnosis systems to understand if an abnormal measurement is caused by a component degradation or by a sensor fault is also investigated. The data used both to train and to test the networks is generated from a deterministic model and later modified to consider noise or bias in the sensors. The application of Bayesian belief networks to fuel cell - gas turbine hybrid systems is novel, thus the results obtained from this analysis could be a significant starting point to understand their potential. The diagnosis systems developed for this work provide essential information regarding levels of degradation and presence of faults in gas turbine, fuel cell and sensors in a fuel cell – gas turbine hybrid system. The Bayesian belief networks proved to have a good level of accuracy for all the scenarios considered, regarding both steady state and transient operations. This analysis also suggests that in the future a Bayesian belief network could be integrated with the control system to achieve safer and more efficient operations of these plants.

Algorithms for Bayesian Belief-Network Precomputation

1991 ◽  
Vol 30 (02) ◽  
pp. 81-89 ◽  
Author(s):  
E. H. Herskovits ◽  
G. F. Cooper
Keyword(s):  
Computational Complexity ◽  
Expert Systems ◽  
Expected Utility ◽  
Bayesian Belief Network ◽  
Bayesian Belief Networks ◽  
Future Research ◽  
Belief Networks ◽  
Major Drawback ◽  
Belief Network ◽  
General Method

AbstractBayesian belief networks provide an intuitive and concise means of representing probabilistic relationships among the variables in expert systems. A major drawback to this methodology is its computational complexity. We present an introduction to belief networks, and describe methods for precomputing, or caching, part of a belief network based on metrics of probability and expected utility. These algorithms are examples of a general method for decreasing expected running time for probabilistic inference.We first present the necessary background, and then present algorithms for producing caches based on metrics of expected probability and expected utility. We show how these algorithms can be applied to a moderately complex belief network, and present directions for future research.

scholarly journals Technical Development Issues and Dynamic Modeling of Gas Turbine and Fuel Cell Hybrid Systems

1999 ◽  
Author(s):  
Eric A. Liese ◽  
Randall S. Gemmen ◽  
Faryar Jabbari ◽  
Jacob Brouwer
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Dynamic Modeling ◽  
Hybrid System ◽  
Dynamic Models ◽  
Cell Model ◽  
Dimensional System ◽  
Modeling Tools ◽  
Steam Reformer

This paper describes safety issues important to the operation of combined fuel cell and gas turbine (hybrid) systems, and provides motivation for building dynamic modeling tools to support their development. It also describes two models — a steam reformer and a fuel cell — that will be used to investigate the dynamic performance of a hybrid system. The present goals are to develop dynamic models for these two components, ensure their reliability, and obtain a basic understanding of their performance prior to integration into a complete hybrid system model. Because of the large physical domain to be analyzed in the integrated hybrid system, both reformer and fuel cell models are simplified to a one-dimensional system of equations. Model results are presented for a tubular, counterflow steam reformer showing methane conversion and temperature behavior during initial startup, and following several step change perturbations. For the fuel cell model, a generic planar type is analyzed showing voltage and current behavior following step changes in load resistance and fuel input. The results provide confidence in each model’s reliability, enabling them to be integrated for hybrid system simulation. Results from the integrated simulations will provide guidance on future hybrid technology development needs.

Fuel-Cell Hybrid Systems to Generate Shipboard Electrical Power

2009 ◽  
Author(s):  
W. J. Sembler ◽  
S. Kumar
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Air Quality ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Cell Hybrid ◽  
Electrical Power ◽  
History Of ◽  
Marine Applications ◽  
Fuel Cell Hybrid

The reduction of shipboard airborne emissions has been receiving increased attention due to the desire to improve air quality and reduce the generation of greenhouse gases. The use of a fuel cell could represent an environmentally friendly way for a ship to generate in-port electrical power that would eliminate the need to operate diesel-driven generators or use shore power. This paper includes a brief description of the various types of fuel cells in use today, together with a review of the history of fuel cells in marine applications. In addition, the results of a feasibility study conducted to evaluate the use of a fuel-cell hybrid system to produce shipboard electrical power are presented.

Performance Evaluation of a Molten Carbonate Fuel Cell/Micro Gas Turbine Hybrid System With Oxy-Combustion Carbon Capture

2017 ◽  
Author(s):  
Ji Ho Ahn ◽  
Tong Seop Kim
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Carbon Capture ◽  
Molten Carbonate Fuel Cell ◽  
Design Parameters ◽  
Molten Carbonate ◽  
Micro Gas Turbine ◽  
Carbonate Fuel Cell

Owing to the increasing consumption of fossil fuels and emission of greenhouse gases, interests in highly efficient and low carbon emitting power systems are growing fast. Several research groups have been suggesting advanced systems based on fuel cells and have also been applying carbon capture and storage technology to satisfy the demand for clean energy. In this study, the performance of a hybrid system, which is a combination of a molten carbonate fuel cell (MCFC) with oxy-combustion carbon capture and an indirectly fired micro gas turbine (MGT) was predicted. A 2.5MW MCFC system that is used in commercial applications was used as the reference system so that the results of the study could be applicable to practical situations. The ambient pressure type hybrid system was modeled by referring to the design parameters of an MGT that is currently being developed. A semi-closed type design characterized by flow recirculation was adopted for this hybrid system. A part of the recirculating gas is converted into liquefied carbon dioxide and captured for storage at the carbon separation unit. Almost 100% carbon dioxide capture is possible with this system. In these systems, the output power of the fuel cell is larger than in the normal hybrid system without carbon capture because the partial pressure of carbon dioxide increases. The increased cell power partially compensates for the power loss due to the carbon capture and MGT power reduction. The dependence of net system efficiency of the oxy-hybrid on compressor pressure ratio is marginal, especially beyond an optimal value.

scholarly journals Fuel cell–gas turbine hybrid system design part I: Steady state performance

2014 ◽  
Vol 257 ◽  
pp. 412-420 ◽  
Author(s):  
Dustin McLarty ◽  
Jack Brouwer ◽  
Scott Samuelsen
Keyword(s):  
Steady State ◽  
Fuel Cell ◽  
System Design ◽  
Gas Turbine ◽  
Hybrid System ◽  
Steady State Performance

Evaluation of Cathode Air Flow Transients in a SOFC/GT Hybrid System Using Hardware in the Loop Simulation

2014 ◽  
Author(s):  
Nana Zhou ◽  
Chen Yang ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Mass Flow ◽  
Cell System ◽  
Department Of Energy ◽  
Dynamic Responses ◽  
Partial Recovery ◽  
Fuel Cell System ◽  
Air Mass

Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system, especially during an imposed load transient, can be improved by effective management and control of the cathode air mass flow. The response of gas turbine hardware system and the fuel cell stack to the cathode air mass flow transient was evaluated using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The disturbances of the cathode air mass flow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments. The dynamic responses of the SOFC/GT hybrid system were studied in this paper. The evaluation included distributed temperatures, current densities, heat generation and losses along the fuel cell over the course of the transient along with localized temperature gradients. The reduction of cathode air mass flow resulted in a sharp decrease and partial recovery of the thermal effluent from the fuel cell system in the first 10 seconds. In contrast, the turbine rotational speed did not exhibit a similar trend. The collection of distributed fuel cell and turbine trends obtained will be used in the development of controls to mitigate failure and extend life during operational transients.

Performance Evaluation of a Molten Carbonate Fuel Cell/Micro Gas Turbine Hybrid System With Oxy-Combustion Carbon Capture

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Ji Ho Ahn ◽  
Tong Seop Kim
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Carbon Capture ◽  
Molten Carbonate Fuel Cell ◽  
Design Parameters ◽  
Molten Carbonate ◽  
Micro Gas Turbine ◽  
Carbonate Fuel Cell

Owing to the increasing consumption of fossil fuels and emission of greenhouse gases, interests in highly efficient and low carbon emitting power systems are growing fast. Several research groups have been suggesting advanced systems based on fuel cells and have also been applying carbon capture and storage technology to satisfy the demand for clean energy. In this study, the performance of a hybrid system, which is a combination of a molten carbonate fuel cell (MCFC) with oxy-combustion carbon capture and an indirectly fired micro gas turbine (MGT), was predicted. A 2.5 MW MCFC system that is used in commercial applications was used as the reference system so that the results of the study could be applied to practical situations. The ambient pressure type hybrid system was modeled by referring to the design parameters of an MGT that is currently being developed. A semi-closed type design characterized by flow recirculation was adopted for this hybrid system. A part of the recirculating gas is converted into liquefied carbon dioxide and captured for storage at the carbon separation unit (CSU). Almost 100% carbon dioxide capture is possible with this system. In these systems, the output power of the fuel cell is larger than in the normal hybrid system without carbon capture because the partial pressure of carbon dioxide increases. The increased cell power partially compensates for the power loss due to the carbon capture and MGT power reduction. The dependence of net system efficiency of the oxy-hybrid on compressor pressure ratio is marginal, especially beyond an optimal value.

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