TY - GEN A1 - Rakhi, Rakhi A1 - Günther, Vivien A1 - Richter, Jana A1 - Mauß, Fabian T1 - Steam reforming of methane over nickel catalyst using a one-dimensional model T2 - International Journal of Environmental Sciences N2 - Steam reforming of hydrocarbons is a well established chemical process which provides synthesis gas (H2 and CO). These synthesis products can hence be converted to numerous valuable basic chemicals. For the industrial application of steam reforming, a detailed understanding of the process is a prerequisite. Models that capture the detailed homogeneous and heterogeneous reaction kinetics and the comprehensive transport processes as well as their interaction have the potential to optimize the catalytic process without expensive experimental campaigns. In this paper, a detailed investigation has been done using a multi-step reaction mechanism for modeling steam reforming of methane over nickel-based catalyst using a one-dimensional (1D) model, LOGEcat [1]. The model is applicable to the simulation of all standard after-treatment catalytic processes of combustion exhaust gas along with other chemical processes involving heterogeneous catalysis, such as, the Sabatier process [27]. It is a 1D tool, thus is computationally cost effective and is based on a series of perfectly stirred reactors (PSR). The model is used to perform the simulations for various reactor conditions in terms of temperature, pressure, flow rates and steam-to-carbon (S/C) ratio. Several chemical reaction terms, such as, selectivity, yield, conversion, and mole fraction have been shown with respect to the varied parameters and the results are compared with 2D simulations and experimental reference data. We report a very good agreement of the various profiles produced with 1D model as compared to the reference data. Note that the main aim of this study is to check how far the 1D model can capture the basic chemistry for modeling steam reforming of methane over nickel-based catalysts. It is interesting to note that the cost effective reduced order model is capable to capture the physics and chemistry involved with a multi-step reaction mechanism showing the predictive capability of the model. This study forms the basis for further analysis towards the thermochemistry of the species to develop a kinetically consistent reaction mechanism. Y1 - 2022 UR - https://www.iprjb.org/journals/index.php/IJES/article/view/1520/1605 U6 - https://doi.org/10.47604/ijes.1520 SN - 2519-5549 VL - 5 IS - 1 SP - 1 EP - 32 ER - TY - GEN A1 - Fotiadis, Kyriakos A1 - Asimakopoulou, Akrivi A1 - Baltzopoulou, Penelope A1 - Kastrinaki, Georgia A1 - Koutsonikolas, Dimitrios A1 - Karagiannakis, George A1 - Skevis, George A1 - Richter, Jana A1 - Mauß, Fabian T1 - Experimental Characterization of a Novel Foam Burner Design for the Low-Excess-Enthalpy Combustion of Very Lean Syngas Mixtures T2 - Energies N2 - In the present work, a novel foam burner design is proposed and experimentally evaluated for operation with highly diluted syngas mixtures. The lab-scale burner consists of a purpose-built, square-shaped, high-temperature-grade stainless steel tubular reactor filled with square-sectioned siliconized silico carbide (SiSiC) foams. The assembly was installed in an electrical furnace. Spatially resolved temperature measurements were obtained along the reactor axis, while simultaneous measurements of CO, CO2, H2, O2, and N2 were taken at the burner exit and the water levels were recorded upstream and downstream of the reactor. The results clearly show that flames can be stabilized along the reactor for a range of foam characteristics and operating conditions. Hydrogen conversion efficiencies in excess of 98%, and overall thermal efficiencies close to 95% were achieved for the selected operating conditions. Overall, the denser 10 ppi foam demonstrated superior combustion characteristics in terms of stability, lower enthalpy rises, and a wider operating range at the expense of a very modest pressure drop penalty. Finally, scanning electron microscopy, coupled with energy dispersion spectroscopy (SEM/EDS) and Raman spectroscopy analyses, was used to determine the morphological and compositional characteristics of the pristine and aged foams. After more than 100 h of operation, no significant performance degradation was observed, even though the burner design was subjected to considerable thermal stress. Y1 - 2023 U6 - https://doi.org//10.3390/en16197014 SN - 1996-1073 VL - 16 IS - 19 SP - 7014 ER - TY - GEN A1 - Richter, Jana A1 - Rachow, Fabian A1 - Israel, Johannes A1 - Roth, Norbert A1 - Charlafti, Evgenia A1 - Günther, Vivien A1 - Flege, Jan Ingo A1 - Mauß, Fabian T1 - Reaction Mechanism Development for Methane Steam Reforming on a Ni/Al2O3 Catalyst T2 - Catalysts N2 - In this work, a reliable kinetic reaction mechanism was revised to accurately reproduce the detailed reaction paths of steam reforming of methane over a Ni/Al2O3 catalyst. A steady-state fixed-bed reactor experiment and a 1D reactor catalyst model were utilized for this task. The distinctive feature of this experiment is the possibility to measure the axially resolved temperature profile of the catalyst bed, which makes the reaction kinetics inside the reactor visible. This allows for understanding the actual influence of the reaction kinetics on the system; while pure gas concentration measurements at the catalytic reactor outlet show near-equilibrium conditions, the inhere presented temperature profile shows that it is insufficient to base a reaction mechanism development on close equilibrium data. The new experimental data allow for achieving much higher quality in the modeling efforts. Additionally, by carefully controlling the available active surface via dilution in the experiment, it was possible to slow down the catalyst conversion rate, which helped during the adjustment of the reaction kinetics. To assess the accuracy of the revised mechanism, a monolith experiment from the literature was simulated. The results show that the fitted reaction mechanism was able to accurately predict the experimental outcomes for various inlet mass flows, temperatures, and steam-to-carbon ratios. KW - kinetic reaction mechanism development KW - 1D modeling KW - reaction rates KW - methane steam reforming KW - fixed-bed reactor experiments KW - nickel catalyst Y1 - 2023 U6 - https://doi.org/10.3390/catal13050884 SN - 2073-4344 VL - 13 IS - 5 ER -