Comparison of a fuel-driven and steam-driven ejector in solid oxide fuel cell systems with anode off-gas recirculation: Part-load behavior

Engelbracht, Maximilian; Peters, Roland; Blum, Ludger; Stolten, Detlef

doi:10.1016/j.jpowsour.2014.12.009

Cited by 35 publications

(14 citation statements)

References 9 publications

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“…The electrochemically generated power is considered by P in equation [2]. For the electrochemical reaction only hydrogen is used and converted to steam:…”

Section: Simulation Modelmentioning

confidence: 99%

Analysis of a Solid Oxide Fuel Cell System with Low Temperature Anode Off-Gas Recirculation

et al. 2015

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At Forschungszentrum Jülich, an SOFC system with anode off-gas recirculation loop operating at temperatures up to 160 °C is simulated. To analyze the effect of anode off-gas recirculation, a dynamical system model was implemented in Matlab/Simulink®. The results show that the recirculation rate has a significant effect on the electrical efficiency. In principle, at constant current density high recirculation rates decrease the cell voltage and increase the power demand of the recirculation blower. Therefore, the highest electrical efficiency can be reached with high system fuel utilization, low recirculation rate and in consequence high stack fuel utilization. On the other hand less amount of steam is available for the reforming reaction at low recirculation rates. Therefore, the minimum recirculation rate is determined by the risk of carbon formation. An optimal operation range to avoid carbon formation and to ensure a high electrical efficiency requires recirculation rates between 65 and 70 % and system fuel utilizations above 90 %.

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“…The electrochemically generated power is considered by P in equation [2]. For the electrochemical reaction only hydrogen is used and converted to steam:…”

Section: Simulation Modelmentioning

confidence: 99%

Analysis of a Solid Oxide Fuel Cell System with Low Temperature Anode Off-Gas Recirculation

et al. 2015

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“…The anode offgas recycle (AOR), through which the anode offgas is partially recycled to the anode inlet, has been used in recent research to increase SOFC system efficiency [31][32][33][34]. For the hydrogen-fueled SOFC system ( Figure 2) decoupling controller designing, the plant output variables are difficult to manage independently because of the lack of control inputs needed to construct the input-output pairs.…”

Section: Introductionmentioning

confidence: 99%

“…The AOR is suitable in managing the system-level decoupling control of hydrogen-fueled SOFC because the hydrogen-fueled SOFC without reform reactions requires less heat generated by the burner for system heat self-sustenance, and the AOR can prevent the excessive hydrogen in the offgas from entering the burner to generate useless heat. Although many previous works have employed the AOR to improve system efficiency [31][32][33][34], its function in system-level control is first investigated in the current study.…”

Section: Introductionmentioning

confidence: 99%

Control System Based on Anode Offgas Recycle for Solid Oxide Fuel Cell System

Zhan

Yang

2018

Mathematical Problems in Engineering

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The conflicting operation objectives between rapid load following and the fuel depletion avoidance as well as the strong interactions between the thermal and electrical parameters make the SOFC system difficult to control. This study focuses on the design of the decoupling control for the thermal and electrical characteristics of the SOFC system through anode offgas recycling (AOR). The decoupling control system can independently manipulate the thermal and electrical parameters, which interact with one another in most cases, such as stack temperatures, burner temperature, system current, and system power. Under the decoupling control scheme, the AOR is taken as a manipulation variable. The burner controller maintains the burner temperature without being affected by abrupt power change. The stack temperature controller properly coordinates with the burner temperature controller to independently modulate the stack thermal parameters. For the electrical problems, the decoupling control scheme shows its superiority over the conventional controller in alleviating rapid load following and fuel depletion avoidance. System-level simulation under a power-changing case is performed to validate the control freedom between the thermal and electrical characteristics as well as the stability, efficiency, and robustness of the novel system control scheme.

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“…This definition is common in literature [8,10,13] and is also used throughout this work. This definition is common in literature [8,10,13] and is also used throughout this work.…”

Section: Introductionmentioning

confidence: 99%

“…The recirculation rate R can be arbitrarily based on mass, volume or molar flow as it always results in the same value. This definition is common in literature [8,10,13] and is also used throughout this work. Note that the name for ω and R varies in literature and especially variations of recirculation/ recycle rate/ratio are commonly used for both definitions.…”

Section: Introductionmentioning

confidence: 99%

Gas Recirculation at the Hydrogen Electrode of Solid Oxide Fuel Cell and Solid Oxide Electrolysis Cell Systems

et al. 2016

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In this study it is theoretically analyzed how flue gas recirculation at the hydrogen electrode of solid oxide cells (SOC) systems effects fuel utilization and carbon formation. Interdepence between cell fuel utilization, system fuel utilization and gas recirculation is investigated numerically. Tendency towards carbon deposits is evaluated via thermodynamic equilibrium calculations. It is quantified which gas recirculation rates are necessary to achieve high values of system fuel utilization even if the cell fuel utilization is kept at a moderate level. Furthermore, tendency towards carbon deposition strongly depends on temperature, pressure and feed gas composition and can be reduced by adequate recirculation rates. The presented results can be used for the configuration of gas recirculation in SOC systems.

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Comparison of a fuel-driven and steam-driven ejector in solid oxide fuel cell systems with anode off-gas recirculation: Part-load behavior

Cited by 35 publications

References 9 publications

Analysis of a Solid Oxide Fuel Cell System with Low Temperature Anode Off-Gas Recirculation

Analysis of a Solid Oxide Fuel Cell System with Low Temperature Anode Off-Gas Recirculation

Control System Based on Anode Offgas Recycle for Solid Oxide Fuel Cell System

Gas Recirculation at the Hydrogen Electrode of Solid Oxide Fuel Cell and Solid Oxide Electrolysis Cell Systems

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