Reformer faults in SOFC systems: Experimental and modeling analysis, and simulated fault maps

Greco, A.; Sorce, Alessandro; Littwin, R.; Costamagna, Paola; Magistri, Loredana

doi:10.1016/j.ijhydene.2014.09.063

Cited by 55 publications

(24 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then, the reactions kinetics slows down, the heat transfer through the external walls becomes the prevailing effect, and the temperature of the reacting mixture raises up to a value of about 910 K at the reactor outlet. The temperature operating range of the reactor is in line with that previously reported for a simulated fuel processor embedded into an SOFC system [2]. Figure 11 reports molar fractions along the axis of the reactor, displaying methane and water consumption occurring together with hydrogen and carbon monoxide and dioxide production.…”

Section: Sofc Plant Scale Ngsr Reactorsupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

“…The model is steady state and includes the local mass balance, the local energy balance and also the momentum balance under the form of Darcy's law ( Table 2). The operating conditions, derived from previous SOFC system simulations [2], are as follows: operating pressure 1 atm, fuel flow rate 2 10 -3 m 3 min -1 (referred to normal conditions: 1 atm, 273.15 K); fuel composition 90% methane, 10% hydrogen. The fuel is then mixed with steam (S/C = 2), and fed into the reactor with an inlet temperature 844 K. In order to keep the reactor at the desired temperature, 0.16 kW electrical power is considered to be supplied to the external heating jacket.…”

Section: Sofc Plant Scale Ngsr Reactormentioning

confidence: 99%

“…The importance of early detection, isolation, identification and possibly correction of faults, has been evidenced by previous research works on solid oxide fuel cell (SOFC) plants . With reference to the SOFC power plant scheme reported in (Figure , the possible types of faults have been grouped into four main categories (classes) , : (i) air leakage: this fault consists in leakage of air between the air blower and the SOFC stack itself; (ii) fuel leakage: in the reformer, the methane/steam feed is converted into a hydrogen rich mixture. Leakage is likely to occur between the exit of the reformer and the entrance of the SOFC stack because of the small dimensions and high diffusivity of the hydrogen molecule; (iii) SOFC stack degradation: an increase of the SOFC internal losses (activation, ohmic and diffusion losses) leads to a reduced electrochemical performance and efficiency.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Diagnostics and Prognostics‐Oriented Modeling of an NGSR Fuel Processor for Application in SOFC Systems

et al. 2017

Self Cite

View full text Add to dashboard Cite

Diagnostics and prognostics of natural gas steam reforming (NGSR) reactors are of utmost importance for solid oxide fuel cell (SOFC) systems, where a fuel processor fault can cause damage to the SOFC stack. Most common faults are due to carbon deposition. We investigate this phenomenon through a model based on microscopic mass, energy and momentum balances of a tubular NGSR reactor. The model includes a detailed local reaction kinetics specific for Ni-based catalysts, and is integrated numerically using a finite element method (FEM) implemented through COMSOL Multiphysics 5.2. Results obtained from the simulation of a laboratory scale reactor are validated on the basis of literature data. Furthermore, the model is applied to an NGSR fuel processor designed for an 1.1 kW SOFC system. The model allows to identify the area where carbon deposition is expected to occur, which is a key feature in view of developing specific diagnostic and prognostic tools. The simulation results demonstrate that safety criteria based on the feedstock steam to carbon (S/C) ratio can be misleading in a number of operating conditions.

show abstract

Section: Sofc Plant Scale Ngsr Reactorsupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: Sofc Plant Scale Ngsr Reactormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Diagnostics and Prognostics‐Oriented Modeling of an NGSR Fuel Processor for Application in SOFC Systems

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…The development of innovative complex power plants [1,2], such as hybrid systems based on Solid Oxide Fuel Cell (SOFC) technology [3], showed critical issues in performing experimental tests [4]. These are essential activities to complete the system knowledge, to validate the calculation models, to optimize the components and technology aspects, to develop low cost solutions, and to increase the plant reliability [5][6][7][8]. Even if the modeling activities can significantly help researchers and engineers, the experimental approach cannot be completely avoided.…”

Section: Introductionmentioning

confidence: 99%

Hardware-in-the-Loop Operations With an Emulator Rig for SOFC Hybrid Systems

Ferrari

Sorce

Massardo

2017

Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration Applications; Org

View full text Add to dashboard Cite

This paper shows the Hardware-In-the-Loop (HIL) technique developed for the complete emulation of Solid Oxide Fuel Cell (SOFC) based hybrid systems. This approach is based on the coupling of an emulator test rig with a real-time software for components which are not included in the plant. The experimental facility is composed of a T100 microturbine (100 kW electrical power size) modified for the connection to an SOFC emulator device. This component is composed of both anodic and cathodic vessels including also the anodic recirculation system which is carried out with a single stage ejector, driven by an air flow in the primary duct. However, no real stack material was installed in the plant. For this reason, a real-time dynamic software was developed in the Matlab-Simulink environment including all the SOFC system components (the fuel cell stack with the calculation of the electrochemical aspects considering also the real losses, the reformer, and a cathodic recirculation based on a blower, etc.). This tool was coupled with the real system utilizing a User Datagram Protocol (UDP) data exchange approach (the model receives flow data from the plant at the inlet duct of the cathodic vessel, while it is able to operate on the turbine changing its set-point of electrical load or turbine outlet temperature). So, the software is operated to control plant properties to generate the effect of a real SOFC in the rig. In stand-alone mode the turbine load is changed with the objective of matching the measured Turbine Outlet Temperature (TOT) value with the calculated one by the model. In grid-connected mode the software/hardware matching is obtained through a direct manipulation of the TOT set-point. This approach was essential to analyze the matching issues between the SOFC and the micro gas turbine devoting several tests on critical operations, such as start-up, shutdown and load changes. Special attention was focused on tests carried out to solve the control system issues for the entire real hybrid plant emulated with this HIL approach. Hence, the innovative control strategies were developed and successfully tested considering both the Proportional Integral Derivative and advanced approaches. Thanks to the experimental tests carried out with this HIL system, a comparison between different control strategies was performed including a statistic analysis on the results The positive performance obtainable with a Model Predictive Control based technique was shown and discussed. So, the HIL system presented in this paper was essential to perform the experimental tests successfully (for real hybrid system development) without the risks of destroying the stack in case of failures. Mainly surge (especially during transient operations, such as load changes) and other critical conditions (e.g. carbon deposition, high pressure difference between the fuel cell sides, high thermal gradients in the stack, excessive thermal stress in the SOFC system components, etc.) have to be carefully avoided in complete plants.

show abstract

Problems and Solutions for Future Hybrid Systems

2017

Hybrid Systems Based on Solid Oxide Fuel Cells

View full text Add to dashboard Cite

Reformer faults in SOFC systems: Experimental and modeling analysis, and simulated fault maps

Cited by 55 publications

References 40 publications

Diagnostics and Prognostics‐Oriented Modeling of an NGSR Fuel Processor for Application in SOFC Systems

Diagnostics and Prognostics‐Oriented Modeling of an NGSR Fuel Processor for Application in SOFC Systems

Hardware-in-the-Loop Operations With an Emulator Rig for SOFC Hybrid Systems

Problems and Solutions for Future Hybrid Systems

Contact Info

Product

Resources

About