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In order to improve the energy efficiency of the Sabatier reactor-based power-to-gas process, molten carbonate fuel cells and solid oxide electrolyzers were installed instead of a conventional amine CO 2 capture system and a classical alkaline electrolyzer. The plant is a multi-module prototype with a nominal capacity of 50 kW consisting of two SOE-MCFC units. The system was commissioned in 2022. The article describes the theoretical basis. The initial assumptions that were formulated at the stage of preparing for the research investment, as well as the deviations from them that became the result of detailed design were presented. The developed startup and shutdown procedures, as well as the first results of pioneering research were shown. The trial operation of the system was intended to provide information on integrated SOE-MCFC module and its performance and efficiency. The basic barriers for market implementation and recommendations for future research were discussed. The optimal operating point for hydrogen production needed 35.8 kWh/kgH 2. Thus, electrical energy conversion to chemical energy efficiency is 93.9%. Flow preheating and electrical auxiliary heater power are not included. An MCFC at its ideal functioning point (around 4 kW el) outputs 5.4 kg/h of CO 2 separated. • Operational experience of upgraded novel P2G installation is reported. • A start-up procedure of MCFC-SOE tandem in proposed and experimentally verified. • Energy required for synthesis of a kilogram of hydrogen was 35.8 kWh/kgH 2. [ABSTRACT FROM AUTHOR]

The paper presents a comparison of the models currently used in relation to the available experimental data. The review highlights the main causes of discrepancies between the results of modeling and experimental data. The models are based on factors that have no physical interpretation and are used only as "fitting parameters". This hampers use of these models in simulations on states other than those that prevailed during the experiments for which the coefficients were determined. • Comparison of the models of proton conducting Solid Oxide Fuel Cells is done. • Main modeling parameters are selected. • Inaccuracies against experimental data are investigated. [ABSTRACT FROM AUTHOR]

The article provides an overview of knowledge on how to model fuel cells using software which is oriented to system modeling. The overview covers several types of fuel cell such as SOFC, MCFC and PEMFC. Fuel cells were modeled using mainly three types of software, i.e. Aspen Hysys, Aspen Plus and Matlab. Based on our literature review, we decided to use Aspen Hysys to create a proton conducting SOFC model. Model construction is based on a reduced order approach that we published earlier. We used available experimental data to verify the model we created on. The results generated by the model and the experimental data were then subjected to an error analysis. Only two of all the articles found contained a set of information that was fit for the purpose of validating the model. The model maps the work of the proton conducting SOFC with high accuracy, i.e., an error of 0.01 V. • The methodology for model implementation in available software is reported. • The model represents an alternative approach for voltage prediction of a H + SOFC. • A validation process for the models implemented in Aspen Hysys/Excel is presented. [ABSTRACT FROM AUTHOR]

• An alternative approach for voltage prediction of a single cell H-SOFC has been developed. • Model is based only on physical, geometrical and material properties of the fuel cell. • A validation process is done. The aim of this study is to develop a new approach for modeling the voltage of H-SOFC. The proposed 0-D model collects electrochemical, thermal, electrical and flow parameters. The main aim is to have a combination of all cell working conditions in as a low number of factors as possible and to have factors that are relatively easy to determine. Various experimental data was collected and the results of the validation process are shown. Various fuel mixtures across relatively wide ranges of parameters were used to validate the model. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrolyzer and fuel cell integrated in an enhanced power-to-gas system. • No energy penalty for CO 2 capture, in a system with lower power requirements. • CO 2 separation exceeds 90 percent. This study outlines a concept for improving a power-to-gas (P2G) system through the implementation of highly efficient high-temperature electrolysis combined with a molten carbonate fuel cell (MCFC) as a CO 2 capture unit for a power plant. Laboratory scale experiments demonstrate that the MCFC could be used for CO 2 separation, opening the way to capture of CO 2 from flue gases at coal-fired power stations, while maintaining both high electric efficiency and a high CO 2 separation factor. Improved energy efficiency can be achieved by the lower electricity requirement of high temperature electrolysis compared to other technologies. Results obtained from experimental investigations show that a CO 2 separation rate in excess of 90 % is achievable through adjusting the cathode inlet flow. It should be noted that flue gas must be mixed with air before delivery to the MCFC. Controlled flow of inlet gases to the anode can raise electric efficiency to above 35 % for both laboratory-size and full-scale MCFC. The benefits of the concept are manifested by lower power consumption of the system and no energy penalty for the CO 2 capture process. Additionally, the system enjoys good thermal management because all devices run at elevated temperatures (Sabatier reactor at 300 °C, MCFC at 650 °C, solid oxide electrolyzer at 700–800 °C). The proposed improvements increase the system's competitiveness relative to alternative P2G systems and reduce the price of substitute natural gas. Secondly, it will eliminate the consumption of heat from the host coal-fired power plant. Thirdly, the entire system will be more straightforward, compact, and modular, allowing any future scale-up to be implemented without technological difficulties. Finally, the amount of energy required to produce hydrogen will decline by around 25 %. [ABSTRACT FROM AUTHOR]