1,720,970 research outputs found
Extension of an effective MCFC kinetic model to a wider range of operating conditions
No full textThe aim of this work is to improve the semi-empirical MCFC kinetics model previously developed by the authors for laboratory and industrial simulation to make it applicable to a wider range of feeding compositions. New parameters are taken into account and identified to describe O2 and cathode induced flux effects, which were neglected in the previous formulation. The newly obtained equation is integrated as kinetic core in the SIMFC (SIMulation of Fuel Cells) code, an MCFC 3D model set up by the UNIGE PERT group, to test its reliability. Validation is performed using experimental data collected through experimental tests carried out at the Fuel Cell Research Centre laboratories of the Korea Institute of Science and Technology (KIST) using 100 cm2 single cell facilities. The results will be discussed in detail giving examples of the simulated performance varying operating conditions and evaluating the different polarisation contributions. Through the final formulation the average percentage error obtained for all the simulated cases respect to experimental results is maintained around 1% despite the very wide operating range
2D simulation for CH4internal reforming-SOFCs: An approach to study performance degradation and optimization
No full textSolid oxide fuel cells (SOFCs) are a well-developed technology, mainly used for combined heat and power production. High operating temperatures and anodic Ni-based materials allow for direct reforming reactions of CH4 and other light hydrocarbons inside the cell. This feature favors a wider use of SOFCs that otherwise would be limited by the absence of a proper H2 distribution network. This also permits the simplification of plant design avoiding additional units for upstream syngas production. In this context, control and knowledge of how variables such as temperature and gas composition are distributed on the cell surface are important to ensure good long-lasting performance. The aim of this work is to present a 2D modeling tool able to simulate SOFC performance working with direct internal CH4 reforming. Initially thermodynamic and kinetic approaches are compared in order to tune the model assuming a biogas as feed. Thanks to the introduction of a matrix of coefficients to represent the local distribution of reforming active sites, the model considers degradation/poisoning phenomena. The same approach is also used to identify an optimized catalyst distribution that allows reducing critical working conditions in terms of temperature gradient, thus facilitating long-term applications
Kinetic modelling of molten carbonate fuel cells: Effects of cathode water and electrode materials
No full textThrough previous campaigns the authors developed a semi-empirical kinetic model to describe MCFC performance for industrial and laboratory simulation. Although effective in a wide range of operating conditions, the model was validated for specific electrode materials and dry feeding cathode compositions.
The new aim is to prove that with appropriate improvements it is possible to apply the model to MCFC provided by different suppliers and to new sets of reactant gases. Specifically, this paper describes the procedures to modify the model to switch among different materials and identify a new parameter taking into account the effects of cathode water vapour.
The new equation is integrated as the kinetic core within the SIMFC (SIMulation of Fuel Cells) code, an MCFC 3D model set up by the PERT group of the University of Genova, for reliability test. Validation is performed using data collected through tests carried out at the University of Perugia using single cells.
The results are discussed giving examples of the simulated performance with varying operating conditions. The final formulation average percentage error obtained for all the simulated cases with respect to experimental results is maintained around 1%, despite the difference between the basic and the new conditions and facilities
Erratum to “Kinetic modelling of molten carbonate fuel cells: Effects of cathode water and electrode materials” (Journal of Power Sources (2016) 330 (18–27)(S0378775316311430) (10.1016/j.jpowsour.2016.08.123))
No full textThe publisher regrets that caption text has been incorrectly placed for Figures 5 and 8. The corrections are as follows: • Part of the caption for Figure 5 appears on p. 23 “c) H2O molar fraction of 30% ... the water presence at the cathode side (dashed line)”. This should be deleted.• Part of the caption for Figure 8 appears on p. 24 “(b) map of the anode CO2 molar fraction values ... with no water vapour in the cathode feed”. This should be appended to the end of the current caption for Figure 8 with the lettering amended. The full caption of Figure 8 should be: “Fig. 8. (a) Map of the current density values over the surface of the cell working in the reference conditions (b) map of the anode CO2 molar fraction values over the surface of the cell working in reference conditions; maps of the cathode polarization resistance values over the surfaces of the cell: (c) shows the map of the resistance of a cell fed with 30% of water vapour, while (d) shows the map of resistance of a cell with no water vapour in the cathode feed.”The publisher would like to apologise for any inconvenience caused
Erratum to âKinetic modelling of molten carbonate fuel cells: Effects of cathode water and electrode materialsâ (Journal of Power Sources (2016) 330 (18â27)(S0378775316311430) (10.1016/j.jpowsour.2016.08.123))
No full textThe publisher regrets that caption text has been incorrectly placed for Figures 5 and 8. The corrections are as follows: ⢠Part of the caption for Figure 5 appears on p. 23 âc) H2O molar fraction of 30% ⦠the water presence at the cathode side (dashed line)â. This should be deleted.⢠Part of the caption for Figure 8 appears on p. 24 â(b) map of the anode CO2 molar fraction values ⦠with no water vapour in the cathode feedâ. This should be appended to the end of the current caption for Figure 8 with the lettering amended. The full caption of Figure 8 should be: âFig. 8. (a) Map of the current density values over the surface of the cell working in the reference conditions (b) map of the anode CO2 molar fraction values over the surface of the cell working in reference conditions; maps of the cathode polarization resistance values over the surfaces of the cell: (c) shows the map of the resistance of a cell fed with 30% of water vapour, while (d) shows the map of resistance of a cell with no water vapour in the cathode feed.âThe publisher would like to apologise for any inconvenience caused
A feasibility assessment of a retrofit Molten Carbonate Fuel Cell coal-fired plant for flue gas CO<sub>2</sub> segregation
Full text linkThis work considers the use of a Molten Carbonate Fuel Cell (MCFC) system as a power generation and CO2 concentrator unit downstream of the coal burner of an existing production plant. In this way, the capability of MCFCs for CO2 segregation, which today is studied primarily in reference to large-scale plants, is applied to an intermediate-size plant highlighting the potential for MCFC use as a low energy method of carbon capture. A technical feasibility analysis was performed using an MCFC system-integrated model capable of determining steady-state performance across varying feed composition. The MCFC user model was implemented in Aspen Custom Modeler and integrated into the reference plant in Aspen Plus. The model considers electrochemical, thermal, and mass balance effects to simulate cell electrical and CO2 segregation performance. Results obtained suggest a specific energy requirement of 1.41 MJ kg CO2−1 significantly lower than seen in conventional Monoethanolamine (MEA) capture processes.</p
Process analysis of a molten carbonate fuel cell on-board application to reduce vessel CO2 emissions
No full textThe International Maritime Organization has promulgated a set of regulations that demand for the reduction of CO2 emission. Specifically, a reduction of 40% and 70% compared to 2008 is required by 2030 and 2050, respectively. A rough estimate suggests that 20% can be obtained with speed and routes optimisation, while the residual reduction requires the use of more sustainable technology. To achieve the latter objective in a short time, the authors propose existing vessel retrofitting using molten carbonate fuel cells (MCFCs). Indeed, MCFCs allow for additional energy production while capturing CO2 emitted by the conventional vessel engines. Using the software Aspen Plus coupled with the homemade SIMFC code, the system has been simulated and the results show the proposed solution as very promising. In particular, also the impact on the performance of an additional membrane system for CO2 finishing and of different recycle configurations for unreacted H2 recovery is discussed
Experimental influence of operating variables on the performances of MCFCs under SO2 poisoning
No full textProcess analysis of molten carbonate fuel cells in carbon capture applications
No full textRecently, Molten Carbonate Fuel Cells (MCFCs) are being increasingly investigated for carbon capture applications. The wet and low CO2 cathode feeds of such applications can substantially affect the electrochemistry of the cell. A dual-anion mechanism has been introduced to model this electrochemical regime characterized by the parallel migration of carbonate and hydroxide ions. A model based on this mechanism has been implemented in an in-house-developed Fortran code that has been now integrated into Aspen Plus. The model is able to calculate the main performance parameters on the plane of a cell when geometry as well as feed flow rates, compositions, temperature, pressure, and current density are provided as input data. In the present work, the application of the simulation tool is presented in a process analysis aimed to optimize the formulation of the electrochemical module, further evaluate the controlling factors of the dual-anion mechanism, and discuss possible technological optimizations
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