Shutdown

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Rangachary Mukundan - One of the best experts on this subject based on the ideXlab platform.

  • Spatially resolved degradation during startup and Shutdown in polymer electrolyte membrane fuel cell operation
    Applied Energy, 2019
    Co-Authors: S. Komini Babu, Olivier Lottin, Sophie Didierjean, Adrien Lamibrac, Jérôme Dillet, Dusan Spernjak, Gaël Maranzana, Rodney L Borup, Rangachary Mukundan
    Abstract:

    • Degradation due air/air operation due to startup and Shutdown in fuel cell studied. • The effect of platinum loading, and carbon support material is studied. • A segmented cathode hardware is utilized to study the effect along the flow field. • In-situ and ex-situ characterization were correlated to elucidate the degradation. • Limiting the anode's ability to reduce oxygen to water is key to mitigating loss. A B S T R A C T Polymer electrolyte membrane fuel cells have durability limitations associated with the startup and Shutdown of the fuel cell, which is critical for real-world vehicle commercialization. During startup or Shutdown, there exists an active region (hydrogen/air) and a passive region (air/air) between the cell inlet and outlet. Internal currents are generated in the passive region causing high-potential excursion in the cathode leading to accelerated carbon corrosion. In this study, a segmented cathode hardware is used to evaluate the effect of platinum loading on both cathode and anode, and carbon support material on degradation due to repeated series of startups or Shutdowns. In situ losses in the performance and electrochemical surface area were measured spatially, and ex situ analysis of the catalyst layer thickness and platinum particle size was performed to understand the effect of startup or Shutdown on different membrane electrode assembly materials. Startup degrades the region near anode outlet more, while Shutdown degrades the region near anode inlet more compared to the rest of the electrode. While various system mitigation strategies have been reported in the literature to limit this degradation, one materials mitigation strategy is to limit the anode's ability to reduce oxygen to water through increasing the ratio of platinum loading in the cathode to the anode, or by using a bi-functional catalyst.

S. Komini Babu - One of the best experts on this subject based on the ideXlab platform.

  • Spatially resolved degradation during startup and Shutdown in polymer electrolyte membrane fuel cell operation
    Applied Energy, 2019
    Co-Authors: S. Komini Babu, Olivier Lottin, Sophie Didierjean, Adrien Lamibrac, Jérôme Dillet, Dusan Spernjak, Gaël Maranzana, Rodney L Borup, Rangachary Mukundan
    Abstract:

    • Degradation due air/air operation due to startup and Shutdown in fuel cell studied. • The effect of platinum loading, and carbon support material is studied. • A segmented cathode hardware is utilized to study the effect along the flow field. • In-situ and ex-situ characterization were correlated to elucidate the degradation. • Limiting the anode's ability to reduce oxygen to water is key to mitigating loss. A B S T R A C T Polymer electrolyte membrane fuel cells have durability limitations associated with the startup and Shutdown of the fuel cell, which is critical for real-world vehicle commercialization. During startup or Shutdown, there exists an active region (hydrogen/air) and a passive region (air/air) between the cell inlet and outlet. Internal currents are generated in the passive region causing high-potential excursion in the cathode leading to accelerated carbon corrosion. In this study, a segmented cathode hardware is used to evaluate the effect of platinum loading on both cathode and anode, and carbon support material on degradation due to repeated series of startups or Shutdowns. In situ losses in the performance and electrochemical surface area were measured spatially, and ex situ analysis of the catalyst layer thickness and platinum particle size was performed to understand the effect of startup or Shutdown on different membrane electrode assembly materials. Startup degrades the region near anode outlet more, while Shutdown degrades the region near anode inlet more compared to the rest of the electrode. While various system mitigation strategies have been reported in the literature to limit this degradation, one materials mitigation strategy is to limit the anode's ability to reduce oxygen to water through increasing the ratio of platinum loading in the cathode to the anode, or by using a bi-functional catalyst.

Marko Čepin - One of the best experts on this subject based on the ideXlab platform.

  • Application of Shutdown probabilistic safety assessment
    Reliability Engineering & System Safety, 2018
    Co-Authors: Marko Čepin
    Abstract:

    Abstract Shutdown probabilistic safety assessment represents an extension of probabilistic safety assessment performed for other plant operating states, excluding power operation, which is covered in probabilistic safety assessment. The objective is to present the method of Shutdown probabilistic safety assessment and its application on real nuclear power plant example model to evaluate the feasibility of the future wider use. The main methods are similar to conventional probabilistic safety assessment including the fault tree analysis, the event tree analysis, the common cause failures analysis, the human reliability analysis and the probabilistic data collection and analysis. Results interpretation reveals differences between power and other operating states probabilistic safety assessment. Most of the results have been expected including notable or significant differences among the plat operating states regarding the minimal cut sets, regarding the main risk contributors, regarding the importance factors for equipment, regarding the variability of initiating events contributions which are easily explained due to the differences among the plant operating states. The results revealed a variability of durations of the plant operating states among different Shutdowns, which causes large differences in risk results among different Shutdowns and different overall risk. Such variability may require the adjustment of risk informed decision making methods.

Dusan Spernjak - One of the best experts on this subject based on the ideXlab platform.

  • Spatially resolved degradation during startup and Shutdown in polymer electrolyte membrane fuel cell operation
    Applied Energy, 2019
    Co-Authors: S. Komini Babu, Olivier Lottin, Sophie Didierjean, Adrien Lamibrac, Jérôme Dillet, Dusan Spernjak, Gaël Maranzana, Rodney L Borup, Rangachary Mukundan
    Abstract:

    • Degradation due air/air operation due to startup and Shutdown in fuel cell studied. • The effect of platinum loading, and carbon support material is studied. • A segmented cathode hardware is utilized to study the effect along the flow field. • In-situ and ex-situ characterization were correlated to elucidate the degradation. • Limiting the anode's ability to reduce oxygen to water is key to mitigating loss. A B S T R A C T Polymer electrolyte membrane fuel cells have durability limitations associated with the startup and Shutdown of the fuel cell, which is critical for real-world vehicle commercialization. During startup or Shutdown, there exists an active region (hydrogen/air) and a passive region (air/air) between the cell inlet and outlet. Internal currents are generated in the passive region causing high-potential excursion in the cathode leading to accelerated carbon corrosion. In this study, a segmented cathode hardware is used to evaluate the effect of platinum loading on both cathode and anode, and carbon support material on degradation due to repeated series of startups or Shutdowns. In situ losses in the performance and electrochemical surface area were measured spatially, and ex situ analysis of the catalyst layer thickness and platinum particle size was performed to understand the effect of startup or Shutdown on different membrane electrode assembly materials. Startup degrades the region near anode outlet more, while Shutdown degrades the region near anode inlet more compared to the rest of the electrode. While various system mitigation strategies have been reported in the literature to limit this degradation, one materials mitigation strategy is to limit the anode's ability to reduce oxygen to water through increasing the ratio of platinum loading in the cathode to the anode, or by using a bi-functional catalyst.

Olivier Lottin - One of the best experts on this subject based on the ideXlab platform.

  • Spatially resolved degradation during startup and Shutdown in polymer electrolyte membrane fuel cell operation
    Applied Energy, 2019
    Co-Authors: S. Komini Babu, Olivier Lottin, Sophie Didierjean, Adrien Lamibrac, Jérôme Dillet, Dusan Spernjak, Gaël Maranzana, Rodney L Borup, Rangachary Mukundan
    Abstract:

    • Degradation due air/air operation due to startup and Shutdown in fuel cell studied. • The effect of platinum loading, and carbon support material is studied. • A segmented cathode hardware is utilized to study the effect along the flow field. • In-situ and ex-situ characterization were correlated to elucidate the degradation. • Limiting the anode's ability to reduce oxygen to water is key to mitigating loss. A B S T R A C T Polymer electrolyte membrane fuel cells have durability limitations associated with the startup and Shutdown of the fuel cell, which is critical for real-world vehicle commercialization. During startup or Shutdown, there exists an active region (hydrogen/air) and a passive region (air/air) between the cell inlet and outlet. Internal currents are generated in the passive region causing high-potential excursion in the cathode leading to accelerated carbon corrosion. In this study, a segmented cathode hardware is used to evaluate the effect of platinum loading on both cathode and anode, and carbon support material on degradation due to repeated series of startups or Shutdowns. In situ losses in the performance and electrochemical surface area were measured spatially, and ex situ analysis of the catalyst layer thickness and platinum particle size was performed to understand the effect of startup or Shutdown on different membrane electrode assembly materials. Startup degrades the region near anode outlet more, while Shutdown degrades the region near anode inlet more compared to the rest of the electrode. While various system mitigation strategies have been reported in the literature to limit this degradation, one materials mitigation strategy is to limit the anode's ability to reduce oxygen to water through increasing the ratio of platinum loading in the cathode to the anode, or by using a bi-functional catalyst.