Search

This paper presents research on the impact of the material microstructure on the performance of Molten Carbonate Fuel Cells (MCFC). The study is motivated by the need to increase the operation time of MCFC stacks. As the MCFC stacks are mainly composed of porous materials, the paper shows the impact of the porosity on both fuel cell performance and degradation rate. The study is based on the mathematical model, validated through experiments with varying microstructure parameters, achieving an overall relative error of 8%. The study evaluated the performance of MCFC using anodes with different porosity and found that increasing anode porosity from 40% to 70% led to a nearly two-fold increase in maximum power density. However, from both the degradation test and polarization curves, the optimal level of porosity for the anode is around 55%. The porosity level at 55% ensures the highest catalytic surface of the electrodes and is a compromise between the mechanical properties of the electrode and its electrochemical properties. • New approach of 0D model of MCFC including materials microstructure influence is proposed. • The new model is prepared in MS Excel and Aspen HYSYS environments. • Experimental investigation for materials with predefined microstructire parameters was performed for model validation. • Variant analysis is presented for different porosity, tortuosity and constrictivity of MCFC anode. • An optimal scenario is suggested based on modleing results. [ABSTRACT FROM AUTHOR]

The aim of the paper is to examine the performance of molten carbonate fuel cell, which is supplied with a raw bioethanol, i.e. bioethanol which origins directly from fruit fermentation, without pre-treatment of fermentation products. The composition of raw bioethanol was precisely determined and then the impact of raw bioethanol on the degradation of molten carbonate fuel cells was examined. Steam to carbon ratio of the biofuel has been determined as 5.7 (in comparison to stoichiometry of reaction) which allowed for estimation of hydrogen production during steam reforming process taking place in the anode channel. The results in the form of current-voltage curve was obtained and compared with the same fuel cell fed with pure hydrogen, while the amount of hydrogen was defined as identical with the one after steam reforming of biofuel taking place in the nickel anode channel. Relevant literature studies were focused on the purified fuel or examination of the impact of individual components. Our study proved carbon deposition is not a problem, however solid particles contamination in fermentation product makes it impossible to use fuel cell fueled with fermentation product for longer periods, and prior to supplying fuel cell the bioethanol purification is required. A raw biofuel with its impurities did not have any impact on the anode and current collector surface from physical point of view, but Electrochemical Impedance Spectroscopy analysis shows visible increase of ohmic loses. • Homemade first generation bioethanol composition have been examined. • Manufactured bioethanol has been delivered directly to the MCFC anode without purification. • Performance of MCFC fueled with impure bioethanol has been investigated. • Effect of steam reforming for hydrogen generation and steam to carbon ratio were evaluated. • Pollution on the anode after cell operation was investigated with SEM and EIS. [ABSTRACT FROM AUTHOR]

• Performances of molten carbonate fuel cell with ammonia as fuel are studied. • The optimal operating temperature for cell using ammonia as fuel is 680 °C. • The lower H 2 proportion in fuel mixture, the better the cell performance. • Ammonia as fuel has little effect on the electrodes' loose and porous structure. Hydrogen fuel cells can generate clean and efficient energy, and ammonia as a hydrogen carrier contains more hydrogen in its molecule than hydrogen itself. Utilizing green ammonia as fuel for fuel cells can reduce dependency on fossil fuels. However, there has been less study on the electrochemical performance of ammonia molten carbonate fuel cells (MCFCs). Hence, this paper sets up a single MCFC experimental bench to conduct research on direct ammonia molten carbonate fuel cells. The electrochemical performance of a direct ammonia MCFC is investigated in terms of key parameters such as temperature and the volume flow ratio of NH 3 /H 2 entering the anode. Additionally, Scanning Electron Microscopy (SEM) is employed to study the electrodes of the MCFC. Experimental findings demonstrate that the direct ammonia MCFC performs optimally at 680 °C with a current density of 0.059 A/cm2 and an ammonia conversion rate up to 91.6%. When the mixture gas of NH 3 and H 2 is used as the cell fuel, the current density (0.057 A/cm2) and the conversion rate of NH 3 (84.9%) are higher when the volume flow ratio of NH 3 /H 2 is 9, indicating that the increase of H 2 proportion in the mixed gas will affect the conversion of NH 3. SEM image analysis of the MCFC electrodes post-experiments reveals that ammonia does not destruct the loose and porous structure of MCFC electrodes, affirming that NH 3 can be directly used as the MCFC fuel. [ABSTRACT FROM AUTHOR]