Carbonate Fuel Cell Research Articles

Codoped Ceria Electrolyte for Direct Carbon Fuel Cell with Carbon Fly Ash Fuel

Codoped Ceria Electrolyte for Direct Carbon Fuel Cell with Carbon Fly Ash Fuel

Using MCFC for capturing CO2 from flue gases and delivering to Sabatier reactor for SNG synthesis

In contemporary power generation, enhancing efficiency and mitigating environmental contamination are of paramount importance. The imperative to curtail greenhouse gas emissions stands as a preeminent challenge within this sector. Concurrently, there is a marked surge in the exploitation of renewable energy sources, which, due to their intermittent nature, precipitates the imperative for advanced energy storage solutions. This paper introduces an integrated system designed to address both the reduction of CO2 emissions and the storage of energy. The advocated system integrates a Molten Carbonate Fuel Cell (MCFC), Solid Oxide Electrolysis Cell (SOEC), and a Sabatier reactor. The MCFC is employed for its proficient CO2 capture capabilities at the cathode, exhibiting remarkable efficiency, operational flexibility, and a high CO2 separation quotient. The SOEC is recognized for its effective hydrogen production, leveraging high operational temperatures to augment hydrogen output while diminishing electrical energy consumption through thermal energy substitution. The Sabatier reactor is utilized for catalytic methanation, transforming CO2 into Substitute Natural Gas—a compound predominantly comprising methane and hydrogen with minimal CO2 and water traces. This system facilitates the capture and utilization of over 80% of CO2 from exhaust fumes, achieving an overall energy efficiency of 71%. The system's design and off-design operational parameters were meticulously modeled and analyzed.

Numerical Modeling of Electrolyte-Supported Button Solid Oxide Direct Carbon Fuel Cell Based on Boudouard Reaction

Numerical Modeling of Electrolyte-Supported Button Solid Oxide Direct Carbon Fuel Cell Based on Boudouard Reaction

Techno-Economic and CO2 Emissions Analysis of the Molten Carbonate Fuel Cell Integration in a DRI Production Plant for the Decarbonization of the Steel Industry

Developing low-carbon systems for the steel industry is increasingly considered necessary for contributing to the targets of CO2 emission reduction requested by modern environmental policies. This work focuses on a process for decarbonizing primary steel production by integrating an MCFC system in a DRI production plant based on the Energiron ZR process configuration. An MCFC system can be used to remove CO2 from the flue gases while producing electricity and reducing the net electric consumption of the DRI plant. The reference scenario, the carbon capture case, and an additional hydrogen-based H-DRI system using high temperature electrolysis are simulated using Aspen Plus to evaluate and compare their energy and environmental performance. The results show that even considering the additional power consumption of the complete carbon capture and separation system, the overall electrical consumption of the carbon capture case is decreased by 78 % and the direct CO2 emissions by up to 95 %. Furthermore, reduced electricity consumption reduces scope 2 emissions, increasing the sustainability of the process in the steel industry. On the other hand, the H-DRI case decreases primary energy consumption by 24 % but significantly increase electricity requirement; thus, it represents a better future solution when cheap low-CO2 electricity is available. The plant configurations are compared economically by retrieving investment and operational costs from the open literature to estimate the levelized cost of DRI and the cost of CO2 avoided. The results show that installing the MCFC and the anode purification system increases the investment costs by 38 % compared to a conventional plant. However, the lower electricity consumption and carbon tax expenditure lead to a comparable final DRI product cost. Contrarily, due to the electrolyzer high investment and operational costs, the additional marginal DRI cost of the H-DRI case is 31 % higher. Finally, the sensitivity analysis on the main variable costs shows that, independently from the electricity and natural gas price, the carbon capture case is economically competitive to the reference scenario, considering a carbon tax of 60 €/tCO2 or higher. At the same time, the H-DRI solution requires low electricity prices to be competitive. In conclusion, even if, in the long term, the objective is to completely replace the use of fossil fuels with renewable energy, in the short term, the implementation of MCFC in the DRI plant can significantly reduce the environmental impact of primary steel production without significant economic penalization.

Energy and exergy analysis of an ideal molten carbonate fuel cell (MCFC) and reheat & regenerative braysson cycle hybrid system

Direct energy conversion devices are gaining prominence because of their high efficiency, as the process involves the direct conversion of chemical energy to its electrical counterpart, bypassing the thermal energy phase. Fuel cells work on the principle of a chemical reaction between fuels like Hydrogen, Methane, propane, ammonia, and an oxidizer. The working temperature of the fuel cell is as high as (600 °C–700 °C). Generally, waste heat liberated from the fuel cells was used to generate power by running the Brayton (or) Rankine cycle. This work involves exergy and energy analysis on a hybrid system made of a Molten Carbonate Fuel Cell and reheat & regenerative Braysson cycle. Combining a molten carbonate fuel cell (MCFC) with a Braysson cycle results in a novel hybrid system that offers exciting possibilities for power generation. In the analysis, Molten Carbonate Fuel Cell is assumed to operate at 650 °C, and the turbine inlet temperature (TIT) range of the Braysson cycle is taken as 400 to 600 °C. It has been noticed that different optimum pressure ratio values exist to obtain maximum output of power and maximum efficiencies. Both the exergy and energy efficiencies of the combined cycle increase with the increase in turbine inlet temperature. This combined system depicts maximum energy and exergy efficiency of 96.84% and 95.13%, respectively. Destruction rates of exergy for individual equipment and the total system are also obtained as a function of TIT and pressure ratio. The exergy destruction rates are found to be maximum in the fuel cells. An optimum pressure ratio is found to be 1.4, where fuel consumption is the least and efficiencies are the maximum.

Thermodynamic and Economic Analysis of a Standalone Supercritical Thermal Power Plant Integrated with Molten Carbonate Fuel Cell

A detailed technoeconomic analysis of a standalone steam cycle integrated with molten carbonate fuel cell and an organic Rankine cycle is presented herein. The modeling and thermodynamic analysis of the proposed plant is performed using a commercially available software tool called Cycle Tempo. The response surface methodology tool is employed to develop regression models to predict the plant's energy, exergy efficiencies, and levelized cost of electricity (LCOE) for varying independent factors: fuel utilization factor (uf) CO2 utilization factor (ϕ), and current density (i) of the fuel cell. The response surfaces developed from the models are used to conduct the parametric analyses on the plant. The desirability test performed for multiobjective optimization has shown the optimum plant configuration, with higher energy, exergy efficiencies, and a lower LCOE is obtained for uf = 0.85, ϕ = 60%, and i = 1000 A m−2 With an intent to reduce CO2 emissions, monoethanolamine‐based carbon capture system is implemented to the plant configuration, that exhibits maximum energy efficiency for ϕ = 90%, and results in an LCOE of 6.53 Rs kWh−1.

Artificial Intelligence for Electrochemical Prediction and Optimization of Direct Carbon Fuel Cells Fueled with Biochar

At present, direct carbon fuel cells constitute an emerging energy technology that electrochemically converts solid carbon to electricity with high efficiency. The recent trend of DCFCs fueled with biochar from biomass carbonization as green fuel has reinforced the environmental benefits of DCFCs as a clean and sustainable technology. However, there remain new challenges related to some complex unknown kinetic parameters, X=(αa,αc,σg,i0,a,i0,c,ilO2,ilCO2,c,ilCO2,a,ilCO), of the electrochemical conversion of biochar in DCFCs and there is a need for intelligent techniques for prediction and optimization, refering to the available experimental data. The differential evolution (DE) algorithm, which ranked as one of the top performers in optimization competitions with competitive accuracy and convergence speed, was used here for providing the optimized values of these parameters by minimizing the root mean squared errors (RMSE). The proposed technique was then applied to DCFCs fueled by activated pure carbon (APC) using CO2 and CO/CO2 electrochemical models with RMSE around 10−2 and 10−3, respectively. Then, the CO/CO2 model was applied to a DCFC fueled with almond shell biochar (ASB), which displayed a slight increase in RMSE (of the order of 10−2) due to the complex porous structure of ASB and the content of additional chemical elements that affect the electrochemistry of the DCFC and are not considered in the model.

Performance Improvement of a Direct Carbon Fuel Cell through an Irreversible Vacuum Thermionic Generator

A novel hybrid system consisting of a direct carbon fuel cell (DCFC), a thermionic generator (TIG), and a regenerator is developed to recover the exhaust heat from the fuel cell. Expressions for the power output and efficiency of subsystems and the hybrid system are derived. Based on the energy balance equation, the area matching problem between the DCFC and the TIG is discussed and solved. By considering the main irreversibilities, the influences of the DCFC’s current density and the TIG’s voltage on the performance of the hybrid system are revealed. The maximum power output density and the corresponding efficiency of the hybrid system are, respectively, equal to 379 W/m2 and 36%. To enhance the maximum power density of the single DCFC, the optimal regions of the main parameters are determined.

Utilization of Organic Waste in a Direct Carbon Fuel Cell for Sustainable Electricity Generation

There is much organic waste that comes from by-products of agriculture and product processing, solid waste from livestock, and municipal waste. Conventional methods that are widely used for the treatment and management of organic fractions of waste are landfilling, composting, anaerobic digestion, incineration, gasification, and pyrolysis. Among the above methods, pyrolysis is a relatively simple, robust, and scalable technology for transforming diverse organic waste feedstock into renewable energy products. Recently, the electrochemical conversion of biochar into electricity in direct carbon fuel cells (DCFC) has also been investigated and shown to be feasible and highly efficient. This paper focuses on the utilization of organic waste as a fuel and the investigation of their characteristics during electrochemical reactions in molten hydroxide direct carbon fuel cells (MH-DCFCs). Organic waste of different origins (the food-processing industry, urban and suburban areas, municipal solid organic waste, sewage sludge) with diversified characteristics was used as the main feedstock. The lowest power density was determined for sewage sludge (5.1 mW cm−2), and the best results were obtained for peanut shells (53.14 mW cm−2). This study concludes that higher elemental carbon, lower ash content and the presence of reactive surface oxygen functional groups in biochar obtained from organic waste might contribute to better cell performance. Moreover, the research establishes the potential of carbonized organic waste as a prospective alternative fuel source for power generation in an MH-DCFC.

A Review of On-Board Carbon Capture and Storage Techniques: Solutions to the 2030 IMO Regulations

The maritime sector is among the most polluting industrial sectors in the world. To oppose this and following the global trend towards carbon neutrality, the International Maritime Organization (IMO) introduced the objective to reduce the CO2 emission of vessels by the year 2030 of 40% and at the same time the European Union will introduce the maritime sector into the ETS system. Therefore, there is a need to reduce the emissions of the working vessels, and this can be accomplished through the Carbon Capture and Storage (CCS). There are many possible CCS technologies that can be applied to vessels: the one that has already been studied the most is the ammine scrubbing of the exhaust gasses. In parallel, other technologies have been proposed to reduce volume and energy needs, which are the Molten Carbonate Fuel Cells (MCFCs), membrane technologies, fixed bed absorption processes and limestone. The review shows how, depending on the used vessel type, the technology to be used may vary, and proposes some preferential options for different applications. The obtained results can be of relevant importance in the present context of energy transition promoting immediate retrofitting to respond to the urgent request for intervention.

Performance and Stability of Molten Carbonate Fuel Cell Cathode Electrode Under Carbon Capture Endurance Tests

Introduction The molten carbonate fuel cell (MCFC) has emerged as one of the promising alternatives for carbon capture from industrial and power generation CO2 sources. MCFC technology is less energy-intensive compared to conventional amine scrubbing that requires a significant amount of energy (steam) for solvent regeneration process.MCFC has been commercially used for distributed power generation, however its use in carbon capture applications has been limited to development activities and a few demonstrations during the past decades. The electrochemical reactions taking place during cell operation involve the CO2 transfer from cathode to anode in the form of carbonate ions resulting in a gas stream with high CO2 concentration on the anode exhaust. Therefore, MCFC stack systems can be combined with conventional combustion-powered generators (coal and/or natural gas-based power plants) for simultaneous CO2 separation, power and hydrogen generation.CO2 capture applications will typically take in flue gas from industrial furnaces, coal and gas fired combined cycle plants as the cathode inlet gas stream having low CO2 concentrations ranging from 4% to 10% by volume and high CO2 utilization (>90%). These CO2-lean conditions may pose a challenge for attaining good mass-transfer performance and life stability, therefore innovative approaches are needed in terms of hardware design and cathode structure to achieve long-term stability.FCE has tested numerous single cells (250 cm2) and technology stacks (30 kW) under carbon capture operating conditions (4-8% CO2 in the cathode inlet as opposed to >12% in baseline MCFC systems) to understand impact of design parameters on performance, life, and to investigate design solutions for further enhancement. Figure 1 highlights the effect of cathode water content on CO2 utilization. It appears that differences exist between the ideal and measured CO2 utilizations, indicating that less CO2 is transferring from the cathode to anode than expected. This CO2 transference reduction becomes more pronounced with higher water concentration, suggesting that a species other than CO3 2- ion, likely hydroxide (OH- ion), may be generated and transported through the electrolyte matrix.This paper will review the cathode material stability and electrochemical performance under long-term carbon-capture operation. The effect of parameters such as water content, gas composition, utilization, and electrolyte chemistry, as well as approaches to enhance the CO2 capture efficiency and life, will be discussed. Figure 1

Investigation of the Abnormal I-V Curve Shape of Hybrid Direct Carbon Fuel Cell Using Lanthanum Strontium Calcium Titanate-Based Anode

Solid oxide direct carbon fuel cell are being developed for use with waste derived materials. To avoid problems of the state-of-art Ni/YSZ anode, perovskite-based anode materials are being investigated. We have fabricated solid oxide fuel cells with La0.2Sr0.25Ca0.45MxTi1-xO3- δ (M=Ni, Fe, or Co) anodes, YSZ electrolyte, and LSM cathode. Electrochemical performance of these cells have been evaluated with both hydrogen and solid carbon as the fuel and promising results have been recorded. For example, fuel cells with La0.2Sr0.25Ca0.45Ni0.05Ti0.95O3- δ anode tested in hybrid direct carbon fuel cell mode reached a maxmium power density of 82.3 mW/cm2 measured in N2 purging gas at 850 °C. During hybrid direct carbon fuel cell testing with solid carbon fuel and nitrogen purging gas, I-V curves obtained showed an abnormal shape between 0.6V to 0.7 V. To investigate the origin of this line shape, we have used methods such as electrochemical impedance spectroscopy, potentiostatic study, analyzing of off gases from fuel cell using gas choromotography, SEM imaging, EDS analysis and Raman mapping of the tested fuel cell. These results can not only help explain the observed shape of I-V curve, but also provide insight into the mechanism of hybrid direct carbon fuel cells, thus benefiting further development of fuel cells for solid waste to energy applications.

The optimal design of solid oxide and molten carbonate fuel cells integration with a CO2 recycling unit: An attempt to reach a clean transition process

High-temperature Solid Oxide Fuel Cell (SOFC) technology has great potential as a clean and effective energy source. However, several issues have prevented their widespread adoption, like high operating costs, difficulty integrating with other components, and being sensitive to fuel contamination. In order to address these challenges, the main novelties of the present work are carbon capture and utilization for clean energy production, using the flue gas condensation process as a cost-effective and energy-efficient strategy, and the combination of Molten Carbonate Fuel Cells (MCFC) for increased energy efficiency and most effective component integration. The proposed novel system is also equipped with a gasifier and vanadium chloride unit for syngas and clean hydrogen production. The system's practicality is evaluated by analyzing the key performance indicators from thermodynamic, exergo-economic, exergo-environmental, and sustainability viewpoints. Also, the Sankey diagram is presented to investigate each component's effectiveness from the exergy destruction facet. According to the findings, at the most optimum design condition, the acceptable energy and exergy efficiencies of 61.06% and 50.66%, respectively, are achieved, revealing the system's effectiveness. The suggested system is also financially attractive since it achieves a reasonable levelized power cost of 17.6 $/MWh at a total cost of 44.1 $/h. The findings show that carbon dioxide recovery is crucial in reducing the pollutants due to the low emission index of 5.01 kg/GWh. Finally, the exergo-environmental index, environmental damage effectiveness, and exergy stability factor have equivalent values of 0.012, 0.59, and 0.54.

Identification of oxygen ion conductivity of Ba doped Bi0.5Na0.5TiO3 (Ba-BNT) based matrix impregnated by lithium/potassium electrolyte for molten carbonate fuel cells

This paper presents the results of research into improving the ionic conductivity of Molten Carbonate Fuel Cell by modifying the matrix material. So far, we have succeeded in using materials such as YSZ and SDC, but we are now trying to use powders based on Ba Na and TiO2. These materials are characterized by their oxygen ion conductivity at elevated temperatures. A matrix of these materials was produced and used to build MCFCs. Based on the experiments carried out and the mathematical model of the fuel cell, the contribution of the oxygen ion conductivity to the total ionic conductivity was determined.

Exhaust Gas Composition of Lignin Reactions in Molten Carbonate Salt of Direct Carbon Fuel Cell Using FactSage

Abstract The most studied molten carbonate-direct lignin fuel cell (MC-LFC) or molten carbonate-direct carbon fuel cell (MC-DCFC) prototypes are those which are fed by fossil fuel. Substituting these fossilized fuels in the MC-DCFC operation with lignin, which is a bio-based carbon, may make this system more efficient, clean, and sustainable. The manipulation module (Mixture) and the computational module (Equilib) of the FactSage package were used to simulate two systems that can represent the anodic compartment of a direct carbon fuel cell based on MC-DCFC. The first system includes lignin and a mixture of molten carbonate (Li2CO3-Na2CO3-Cs2CO3). The second system uses also lignin and a mixture of molten carbonate (Li2CO3-Na2CO3-Cs2CO3) and CO2 gas was also added. The results show the formation of mixed gases in the anodic compartment which are composed of H2, CO, CO2, CH4, and H2O. The relative concentration of each of the species of this mixed gas has an impact on the efficiency of the MC-DCFC. How the relative concentration of these gases in this electrolyte can impact the performance parameters of the MC-DCFC is systematically analyzed. If the operating conditions of the fuel cell are optimized to get a gas composition of mainly CO2 with low amounts of H2, CO, CH4, and H2O in the anode compartment of the MC-DCFC, this will help to improve the conversion efficiency of lignin fuel in the MC-DCFC.

Model-based quantitative characterization of anode microstructure and its effect on the performance of molten carbonate fuel cell

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.

Development of Molten Carbonate Fuel Cell Based on Lignin Fuel Consumption (MC-LFC): Correlation Between Modeling and Experimental Results

Development of Molten Carbonate Fuel Cell Based on Lignin Fuel Consumption (MC-LFC): Correlation Between Modeling and Experimental Results

Experimental investigation of novel molten borate fuel cell supported by an artificial neural network for electrolyte composition selection

This research proposes idea of new kind of high temperature fuel cell – Molten Borate Fuel Cell (MBFC). The idea of new fuel cell is based on technical modification of well-known Molten Carbonate Fuel Cell by changing electrolyte composition to a borate-based mixture. The cell was tested in laboratory conditions as proof-of-concept investigation and reached OCV at around 1 V and 0.05 A/cm2 of current density. The optimization of borate-based electrolyte composition was conducted with a help of ANN and experimentally verified. The deep feedforward artificial neural network (DFF ANN) was proposed in this study to model the behavior of the new Molten Borate Fuel Cell. This modeling approach is well-known as a potent tool for dealing with complicated modeling and prediction tasks. This study presented many network designs for a range of operating circumstances. The ANN has been used to model and optimize the SOFC, MCFC, and PEMFC, but the design and performance of the MBFC were not previously investigated. The innovative type of fuel cells at issue - Molten Borate Fuel Cells - were designed and optimized using a deep learning algorithm. The most advanced model provides a dynamic forecast of fuel cell operation, taking thermal-flow and electrolyte material factors into account. With an average inaccuracy of 0.3%, all the models performed fair enough. An ANN-based technique may also be used to improve cell operating parameters. Moreover, the operating composition of a novel molten borate electrolyte might be improved in terms of electrochemical performance of the fuel cell.

Investigation of the Abnormal I-V Curve Shape of Hybrid Direct Carbon Fuel Cell Using Lanthanum Strontium Calcium Titanate-Based Anode

Solid oxide direct carbon fuel cells are being developed for use with waste derived materials. We have fabricated solid oxide fuel cells with La0.2Sr0.25Ca0.45MxTi1-xO3-δ (M=Ni, Fe, or Co) anodes, YSZ electrolyte, and LSM cathode. Electrochemical performance of these cells has been evaluated with solid carbon as the fuel and promising results have been recorded. For example, fuel cells with La0.2Sr0.25Ca0.45Ni0.05Ti0.95O3-δ anode tested in hybrid direct carbon fuel cell mode reached a maximum power density of 82.3 mW/cm2 measured in N2 purging gas at 850 °C. During hybrid direct carbon fuel cell testing with solid carbon fuel and nitrogen purging gas, I-V curves obtained showed an abnormal shape between 0.6V and 0.7 V. To investigate the origin of this line shape, we have used methods such as electrochemical impedance spectroscopy, potentiostatic study, and analysis of off gases from fuel cell using gas chromatography.

Simulation and Economic Investigation of CO2 Separation from Gas Turbine Exhaust Gas by Molten Carbonate Fuel Cell with Exhaust Gas Recirculation and Selective Exhaust Gas Recirculation

The paper presents a simulation investigation of using a molten carbonate fuel cell (MCFC) combined with exhaust gas recirculation (EGR) or selective exhaust gas recirculation (SEGR) to reduce CO2 emission from the gas turbine in order to cope with climate change problem. EGR or SEGR can be used to concentrate the low-concentration CO2 in gas turbine exhausts. The CO2 concentration is then raised further by adding gas turbine exhaust to the MCFC’s cathode. The suggested gas–steam combined cycle system paired with MCFC and CO2 collection without EGR is contrasted with two novel gas–steam combined cycle systems integrated with MCFC, EGR, or SEGR with CO2 capture (the reference system). The thermal efficiency of the gas–steam combined cycle systems’ integrated MCFC, EGR and SEGR with CO2 collection is 56.08%, which is 1.3% higher than the reference system. The cost of CO2 avoided in the new system with SEGR will be equal to that of the system with the MEA technique for CO2 capture if the MCFC cost is reduced to 904.4 USD/m2.