Extension of an effective MCFC kinetic model to a wider range of operating conditions

Audasso, E.,Bosio, B.,Nam, S. Pergamon Press ; Elsevier Science Ltd 2016 International journal of hydrogen energy Vol.41 No.12

<P>The 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 O-2 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 cm(2) 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. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.</P>

Preliminary model and validation of molten carbonate fuel cell kinetics under sulphur poisoning

Audasso, E.,Nam, S.,Arato, E.,Bosio, B. Elsevier Sequoia 2017 Journal of Power Sources Vol. No.

<P><B>Abstract</B></P> <P>MCFC represents an effective technology to deal with CO<SUB>2</SUB> capture and relative applications. If used for these purposes, due to the working conditions and the possible feeding, MCFC must cope with a different number of poisoning gases such as sulphur compounds. In literature, different works deal with the development of kinetic models to describe MCFC performance to help both industrial applications and laboratory simulations. However, in literature attempts to realize a proper model able to consider the effects of poisoning compounds are scarce.</P> <P>The first aim of the present work is to provide a semi-empirical kinetic formulation capable to take into account the effects that sulphur compounds (in particular SO<SUB>2</SUB>) have on the MCFC performance. The second aim is to provide a practical example of how to effectively include the poisoning effects in kinetic models to simulate fuel cells performances. To test the reliability of the proposed approach, the obtained formulation is implemented in the kinetic core of the SIMFC (SIMulation of Fuel Cells) code, an MCFC 3D model realized by the Process Engineering Research Team (PERT) of the University of Genova.</P> <P>Validation is performed through data collected at the Korea Institute of Science and Technology in Seoul.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Experimental investigation of the effect of Sulphur fed at the cathode side of MCFC. </LI> <LI> Set up of an MCFC kinetic formulation which takes account of the presence of SO<SUB>2</SUB>. </LI> <LI> Performance simulation and validation of MCFC single cells poisoned with SO<SUB>2</SUB>. </LI> </UL> </P>

Double Doped SrTiO₃ Catalysts for CH₄ Dry-Reforming in High Temperature Fuel Cells

Emilio Audasso,Jeong Hyun Park,Young Bae Jun,Chang Hwan Lee,Sung Pil Yoon 한국신재생에너지학회 2022 AFORE Vol.2022 No.9

In situ exsolution of Rh nanoparticles on a perovskite oxide surface: Efficient Rh catalysts for Dry reforming

Emilio Audasso,김윤도,차준영,Viviana Cigolotti,정환수,조영석,김용민,최선희,윤성필,남석우,손현태 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.8

The catalytic activity of the Rh-exsolved Sr0.92Y0.08Ti2O3 perovskite catalyst (SYTRh5) was examined for dry reforming of methane. The exsolution of the Rh nanoparticles over the SYT perovskite oxide surface was carried out under various reducing environments where the extent of Rh exsolution was significantly determined by the reduction time (4, 12, 24 h) and temperature (800, 900, 1,000 oC). STYRh5 catalysts treated at a longer reduction time and a higher reduction temperature revealed formation of larger metallic Rh nanoparticles on the perovskite oxide with higher surface concentration. For dry reforming activity, the SYTRh5 catalysts reduced at 900 and 1,000 oC for 24 h showed significantly higher methane conversion compared to others. The high catalytic performance of the SYTRh5 (900 and 1,000 oC, 24 h) catalysts was attributed to the high coke-resistance of the larger Rh-exsolved nanoparticles and stronger anchoring sites resulted from the exsolution process. Post-analysis TEM images exhibited limited carbon deposition and particle agglomeration of Rh over the SYTRh5 (900 and 1,000 oC, 24 h) catalysts. Lastly, in-situ H2S poisoning was conducted to examine the regeneration ability of SYTRh5. Although catalyst deactivation was observed, the catalytic activity of SYTRh5 (900 and 1,000 oC, 24 h) was completely recovered to the original level once the H2S flow was interrupted, indicating facile desorption of sulfur species from the Rh-exsolved nanoparticles.

Experimental influence of operating variables on the performances of MCFCs under SO₂ poisoning

Di Giulio, N.,Audasso, E.,Bosio, B.,Han, J.,McPhail, S.J. Elsevier 2015 International journal of hydrogen energy Vol.40 No.19

<P><B>Abstract</B></P> <P>Molten Carbonate Fuel Cells have reached the status of commercialization and are now ready for the challenge of market penetration. Nevertheless, new innovative applications such as the use of non-conventional fuels and their possible implementation in a Carbon Capture and Storage system, have given new importance to research activities. In particular, the gas feedings used in these applications contain impurities that can damage MCFCs and, of these, sulphur compounds seem to be the most harmful, even at low concentrations.</P> <P>The aim of this work is to test the effect of SO<SUB>2</SUB> on the role of the operating variables governing the electrochemical kinetics of MCFCs, investigate the relationships and advance additional data necessary for the reading of the complex interaction phenomena taking place in these conditions. The current work is therefore not intended to probe into the fundamental electrochemical mechanisms, but more to validate the window of viable operating conditions that can be expected in real applications. In particular, an experimental campaign was performed, feeding 2 ppm of SO<SUB>2</SUB> to the cathode of MCFC single-cells at different operating temperature and gas partial pressures (H<SUB>2</SUB>, CO<SUB>2</SUB>, O<SUB>2</SUB>), taking into account possible chemical, electrochemical and physical poisoning mechanisms.</P> <P>The experimental tests were performed at the Fuel Cell Research Centre laboratories of KIST (South Korea) and a preliminary theoretical analysis was also proposed to suggest operating strategies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Low temperatures favour the SO<SUB>2</SUB> poisoning effect, especially under 640 °C. </LI> <LI> Optimal range for hydrogen composition is between 40% and 60%. </LI> <LI> The Oxygen concentration does not influence SO<SUB>2</SUB> poisoning for CO<SUB>2</SUB>/O<SUB>2</SUB> < 0.9. </LI> <LI> CO<SUB>2</SUB> compositions under 6% strongly amplify the impact of SO<SUB>2</SUB> poisoning. </LI> </UL> </P>

Electrochemical Impedance Characteristics of a Low-Temperature Single Cell for CO₂/H₂O Co-Reduction to Produce Syngas (CO+H₂)

Min Gwan, Ha,Donghoon, Shin,Jeawoo, Jung,Emilio, Audasso,Juhun, Song,Yong-Tae, Kim,Hee-Young, Park,Hyun S., Park,Youngseung, Na,Jong Hyun, Jang The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.4

In this study, the electrochemical impedance characteristics of CO₂/H₂O co-reduction to produce CO/H₂ syngas were investigated in a low-temperature single cell. The effect of the operating conditions on the single-cell performance was evaluated at different feed concentrations and cell voltages, and the corresponding electrochemical impedance spectroscopy (EIS) data were collected and analyzed. The Nyquist plots exhibited two semicircles with separated characteristic frequencies of approximately 1 kHz and tens of Hz. The high-frequency semicircles, which depend only on the catholyte concentration, could be correlated to the charge transfer processes in competitive CO₂ reduction and hydrogen evolution reactions at the cathodes. The EIS characteristics of the CO₂/H₂O co-reduction single cell could be explained by the equivalent circuit suggested in this study. In this circuit, the cathodic mass transfer and anodic charge transfer processes are collectively represented by a parallel combination of resistance and a constant phase element to show low-frequency semicircles. Through nonlinear fitting using the equivalent circuit, the parameters for each electrochemical element, such as polarization resistances for high- and low-frequency processes, could be quantified as functions of feed concentration and cell voltage.