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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]

This study aims to investigate the environmental and economic impacts of implementing fuel cell and battery-based hybrid configurations. Phosphoric acid and molten carbonate fuel cell systems in the place of diesel generators of a large tanker to supply the vessel's total electricity demand. Environmental and economic analyses of the utilization of the specified fuel cell systems with LiNiCoALO 2 and LiNiMnCoO 2 chemical types of battery cells on a large marine vessel are provided in this paper. In addition, the assessment of the most suitable battery cell and charge-discharge hours for fuel cell systems is carried out with a grid-search algorithm. Six different fuel cell and battery configurations are investigated to obtain the optimum system layout. The results show that the CO 2 emissions could be reduced by up to 49.75% and the lowest electricity production cost is found as 0.181 $/kWh for the current fuel prices with the utilization of molten carbonate fuel cells and LiNiMnCoO 2 battery cells. • Performance comparison between PAFC and MCFC was performed. • Lowest electricity production cost was obtained 0.181 $/kWh. • CO 2 emission of the marine vessel decreased by 49.75%. • MCFC and LiNiMnCoO 2 battery were best option among other cases studied. • Fuel cell-battery hybrid system could reduce fuel consumption by 25.6%. [ABSTRACT FROM AUTHOR]

Thermal management is essential for high-temperature molten carbonate fuel cell (MCFC) because the accumulated waste heat may degrade the durability. In this paper, looped multi-stage thermoacoustically-driven cryocooler (LMTC) is proposed to reuse the waste heat from MCFC for cooling production, which not only can tackle with the thermal management issue but also can provide additional usages. Accounting various irreversible dissipation, the models of MCFC, LMTC and MCFC-LMTC hybrid system are analytically formulated. Performance features of MCFC-LMTC hybrid system are revealed and the advantages are expounded via calculation examples. Calculations indicate that the maximum power density and corresponding efficiency of the hybrid system are 1688.9 W m−2 and 39.7%, which are 11.4% and 1.3% bigger than that of the sole MCFC system, respectively. By comparing with other available systems, the superiority of using LMTC to recover MCFC waste heat for refrigeration is clearly demonstrated. Considerable parametric studies show that the heat-transfer coefficient of hot heat exchange for LMTC is not suggested to be greater than 2.5 × 10−3 W m−2 K−1. In addition, an increase in the working temperature, working pressure of MCFC, reactant concentration or engine stage number of LMTC positively benefits the hybrid system performance, while an increase in the thermodynamic loss coefficient worsens the hybrid system performance. The obtained results may offer new insights into improving the performance of MCFCs through thermal management approaches. [Display omitted] • An MCFC/LMTC hybrid system model is built for electricity and cooling cogeneration. • Models of both MCFC and LMTC are well described. • Key performance indicators for evaluating the hybrid system are formulated. • Performance features of this kind of hybrid system are revealed. • Effects of decisive variables on the hybrid system performance are discussed. [ABSTRACT FROM AUTHOR]

Hybridized engines have become the focus of research nowadays in order to update the existing engines in different transportation sectors. This paper presents a hybridized aircraft engine consisting of a molten carbonate fuel cell system and a commercial turbofan system. The MCFC units are connected to a steam reforming and a water gas shift system. Also, five clean fuels are selected, such as dimethyl ether, hydrogen, ethanol, methane, and methanol, which are combined with different mass ratios to form five different fuel blends. The hybridized aircraft is investigated using three approaches: exergy analysis, exergoeconomic analysis, and exergoenvironmental analysis. It is found that the proposed engine has an average exergetic efficiency of 88% and an average exergy destruction ratio of 12%. The specific exergetic cost of electricity of the engine has an average value of 710 $/GJ for the high-pressure turbine and 230$/GJ for the intermediate and low-pressure turbines, as well as 50 $/GJ for the MCFC. The average specific exergoenvironmental impact of electricity is 14 mPt/MJ for turbines and 4 mPt/MJ for the MCFC. In addition, a blend of ethanol and hydrogen appears to be a viable option economically and environmentally. [Display omitted] • Five alternative fuels are chosen with different concentrations. • Hybridized MCFC-aircraft has 86%–89% high exergetic efficiency. • Hybridized MCFC-aircraft engine has 15% exergy destruction ratio. • The total annual levelized investment of the hybridized system is 76 k $/h. • The total component-related environmental impact rate is less than 40 mPt/h. [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]

Molten carbonate fuel cell (MCFC) allows concentrating the CO 2 from the cathode side to the anode side, generating electricity concurrently. Chemical looping air separation (CLAS) can produce an O 2 and CO 2 mixture stream as cathode feeding gas of MCFC. In this paper, a natural gas-fueled MCFC with internal reforming is integrated with CLAS as O 2 and CO 2 source for high-efficient power generation with CO 2 capture. An O 2 and CO 2 mixture stream is produced from CLAS by recirculating a portion of CO 2 -rich flue gas after the afterburner to CLAS. The system is analyzed through thermodynamic and economic performance. At the baseline case, the plant net power efficiency is 59.5%, with 99.9% CO 2 capture rate. Based on sensitivity analysis, the higher fuel cell temperature and fuel utilization factor can increase the plant net power efficiency, while the steam carbon ratio and the CLAS reduction reactor temperature are preferable to be at lower levels for higher plant net power efficiency. Finally, economic analysis is conducted. With a MCFC specific cost of $1327/kW and a natural gas price of $2.79/million Btu, the cost of electricity (COE) is $0.094/kWh. The results show the proposed system is attractive for natural gas-fueled power generation with CO 2 capture. • Chemical looping air separation provides O 2 and CO 2 for fuel cell cathode. • Besides producing power, molten carbonate fuel cell operates as CO 2 separator. • Net power efficiency of the integrated system is 59.5%. • Cost of electricity of the proposed plant is lower than that of post-combustion. [ABSTRACT FROM AUTHOR]

• A review of solid oxide fuel cell- and molten carbonate fuel cell-driven systems is done. • Thermodynamic, exergoeconomic, and environmental aspects of fuel cell-based tri-generation systems are compared. • The molten carbonate fuel cell-driven system has better thermodynamic performance. • The solid oxide fuel cell-driven system is cost-effective. • The emission of the molten carbonate fuel cell-driven system is lower. The employment of safe and efficient energy conversion methods in various industries is of paramount importance. Fuel cell technology is a reliable prime mover for energy systems. In this paper, a comprehensive study is conducted to compare the thermodynamic, exergo-economic, and environmental facets of employing two types of fuel cells, embracing solid oxide fuel cell and molten carbonate fuel cell, as a driver in a trigeneration system producing cooling, heating, and power. The subsystems consist of a heating unit and a generator-absorber heat exchanger for the solid oxide fuel cell-driven system, and two heating processes for the molten carbonate fuel cell-driven system. The comparisons are made for 1 MW power generation by the fuel cells operating at ambient pressure and 0.85 for the fuel utilization factor. Simulation results show that under the baseline design conditions, the energy and exergy efficiencies of the solid oxide fuel cell-driven system are 74.1% and 37.9%, respectively, whilst these efficiencies for the molten carbonate fuel cell-driven system are 78.5% and 52.4%, correspondingly. Additionally, the comparisons reveal that the molten carbonate fuel cell-driven system outperforms the solid oxide fuel cell-driven one in terms of thermodynamic and environmental performances, but it is also more costly. [ABSTRACT FROM AUTHOR]

Sustainable aviation attracts the attention of academic and industrial research with the aim of lowering the environmental impact and reducing greenhouse gas emissions. This paper presents two proposed high bypass three-shaft turbofan engines combined a molten carbonate fuel cell (MCFC-turbofan) and a solid oxide fuel cell (SOFC-Turbofan). Energy and exergy analyses are conducted to investigate the performance of the aircraft at the cruising operation mode. The used fuels are kerosene and an alternative fuel blend of 75% methane and 25% hydrogen. The results show that the base turbofan has a maximum thrust force of 153 kN, while the SOFC- and MCFC-turbofans have 116 kN and 107 kN, respectively. The thermal and exergy efficiencies are 43.4% and 52% for the base-turbofan, 52.8% and 66.2% for the SOFC-turbofan, and 71% and 87.6% for the MCFC-turbofan. The carbon emissions are reduced from 18 kg/s to about 3.7 kg/s using the alternative fuel blends. The turbofan engine weight increases by 18% using the SOFC and 40% using the MCFC, while the thrust-to-weight-ratio is reduced from 2.7 for the base-turbofan, to 1.5 for the SOFC-turbofan, and 1.06 for the MCFC-turbofan. Adding a fuel cell increases the engine weight but also improves the system performance and reduces the emissions. • The performance of novel hybrid aircraft propulsion system is improved by 20% with SOFC and 80% with MCFC. • The alternative fuels are methane, methanol, ethanol, dimethyl ether, and hydrogen. • A comparison of system performance evaluation is carried out between kerosene and alternative fuels. • The carbon emissions are expected to be reduced by 80%. [ABSTRACT FROM AUTHOR]