TY - GEN A1 - Günther, Vivien A1 - Mauß, Fabian A1 - Klauer, Christian A1 - Schlawitschek, Christiane T1 - Kinetic Monte Carlo simulation of the epitaxial growth of Si(100) T2 - Physica status solidi : C Y1 - 2012 SN - 1610-1634 VL - 9 IS - 10-11 SP - 1955 EP - 1962 ER - TY - GEN A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Si(100)2×1 Epitaxy: A Kinetic Monte Carlo Simulation of the Surface Growth T2 - Physics Procedia Y1 - 2013 SN - 1875-3892 IS - 40 SP - 56 EP - 64 ER - TY - GEN A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Perlman, Cathleen A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Simulation of a Three-Way Catalyst Using Transient Single and Multi-Channel Models T2 - SAE technical paper KW - Simulation of a Three-Way Catalyst Using Y1 - 2017 U6 - https://doi.org/10.4271/2017-01-0966 SN - 0148-7191 SN - 0096-5170 IS - 2017-01-0966 ER - TY - CHAP A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Günther, Vivien A1 - Mauß, Fabian T1 - On the Influence of Inlet Gas Variations and Gas Phase Chemistry in a Three-Way Catalyst T2 - COMODIA - The Ninth International Conference on Modeling and Diagnostics for Advanced, July 25, 2017 - July 28, 2017 N2 - The conversion effects of a three-way catalyst are simulated in previous works using single and multiple representative channel approaches with detailed surface kinetic models. In addition, this article introduces global gas phase chemistry to the model. This allows reflecting ongoing reactions due to incomplete combustion products in low temperature regime. The 1D single-channel model representative for the catalyst is used here. Next to the comparison of the catalyst outlet emissions with and without gas phase chemistry, the transient temperature increase is simulated in order to model the catalysts light off temperature. Additionally, the transient inlet emissions are enhanced to show the influence of water and hydrogen on the modeling results. The heat transfer is modeled by wall heat losses to provide proper heat dissipation out of the catalyst. The modeling results show a good agreement to the experimental data with low computational cost. Y1 - 2017 U6 - https://doi.org/10.1299/jmsesdm.2017.9.A308 ER - TY - GEN A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Simulation of a three-way-catalyst using a transient multi-channel model N2 - The importance to reduce automotive exhaust gas emissions is constantly increasing. Not only the country-specific laws are getting more stringent also the global increase of automobiles is requiring a responsible handling of the issue. The three-way-catalytic converter (TWC) is one of the most common catalysts for the engine exhaust gas after treatment. The reduction of CO, NO and unburned hydrocarbons is fulfilled via oxidation of carbon monoxide and hydrocarbons, and reduction of nitrogen oxides. These conversion effects were simulated in previous works using single channel approaches [e.g. Fröjd/Mauss, SAE International 2011-01-1306] and detailed kinetic models [e.g Chatterjee et al., Faraday Discussions 119 (2001) 371-384 and Koop et al., Appl. Catal.B: Environmental 91 (2009), 47-58]. In this work multiple representative catalyst channels are used to take heat variations in between the catalyst into account. Each channel is split into a user given number of cells and each cell is treated like a perfectly stirred reactor (PSR). The simulation is validated against an experimental four-stroke engine setup with emission outputs fed into a TWC. Next to the emissions the transient temperature increase is simulated in order to model the catalyst light off temperature. The heat transfer is modelled by wall heat losses to provide a proper heat dissipation out of the catalyst. The simulation results show a good agreement to the experimental data with low computational cost. Y1 - 2017 UR - https://unitedscientificgroup.com/conferences/catalysis/2017/pdfs/CCE-2017_Proceedings.pdf N1 - CCE-2017 International Conference on Catalysis and Chemical Engineering Baltimore, USA, February 22 - 24, 2017 SP - S. 103 ER - TY - GEN A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Development of a Physical Parameter Optimizer for 1D Catalyst Modeling on the Example of a Transient Three-Way Catalyst Experiment, 37th International Symposium on Combustion 2018, Dublin N2 - The importance of catalytic after-treatment for automotive emissions is not neglectable concerning current environmental protection discussions. A reasonable and time efficient catalyst model can help to reduce the necessity of time consuming experimental investigations on physical parameters for catalytic converter construction. It can further support the preparation of necessary experimental setups to analyze physical and chemical phenomena in catalysts. Physical parameter and/or chemical kinetic optimizers can be an advanced tool to support computational models in terms of adjustment to an experiment. In this work a physical parameter optimizer is developed and validated against a transient three-way catalyst experiment. The modeling results are compared to the measured data in terms of temperature and emission conversion behavior and show a good agreement. KW - Three-Way Catalyst KW - 1D-Simulation KW - Emissions KW - After Treatment KW - Optimization Y1 - 2018 UR - https://www.researchgate.net/publication/328998399 ER - TY - GEN A1 - Müller, Klaus A1 - Rachow, Fabian A1 - Günther, Vivien A1 - Schmeißer, Dieter T1 - Methanation of Coke Oven Gas with Nickel-based catalysts T2 - International Journal of Environmental Science N2 - For a complete transition from fossil to CO₂ neutral energy supply new energy storage concepts are needed that allow energy supply in times of absence of regenerative power production as during dark doldrums. A promising renewable energy storage approach is the power to gas (to power) technique based on the production of synthetic natural gas (also called e-methane) by methanation of CO₂ with H₂. The latter is usually produced by electrolysis. In any power to gas concept, electrolysis is a very critical part, due to its high costs, stability issues, or limited power of required electrolysers. As an alternative source of hydrogen, we investigate the methanation of coke oven gas (COG). COG is a byproduct of the carbon rich coke production from coal for the steel industry, with a high amount of hydrogen (~60vol%). Coke oven gas furthermore contains CH₄(~25vol%), CO (5-8vol%), and CO₂(1-3vol%), making it an attractive feedstock for the production of synthetic energy carriers like methane. In the present study, the authors investigate the direct conversion of CO and CO₂ from COG into e-methane. Compared to stoichiometric conversion, the COG hydrogen content is too high for catalytic methanation of CO₂. In order to achieve a higher methane yield, the addition of CO₂ from air, flue gas, or coal gasification can compensate the surplus of hydrogen in the coke oven gas. The process is evaluated by the conversion of CO and CO₂, the catalyst selectivity towards higher hydrocarbons for varying temperatures, and the CH₄ yield. KW - Coke Oven Gas KW - CO₂ recycling KW - Power to Gas (PtG) KW - Synthetic Natural Gas (SNG) KW - e-methane KW - Sabatier-Reaction Y1 - 2019 UR - https://www.iaras.org/iaras/home/caijes/methanation-of-coke-oven-gas-with-nickel-based-catalysts UR - https://iaras.org/iaras/filedownloads/ijes/2019/008-0009(2019).pdf SN - 2367-8941 IS - 4 SP - 73 EP - 79 ER - 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 - Rakhi, Rakhi A1 - Shrestha, Krishna Prasad A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Thermodynamic analysis to develop a detailed surface reaction mechanism T2 - Fuel Science - From Production to Propulsion, Aachen, Germany, May 2022 N2 - The reduction of greenhouse gasses such as CO2 and CH4 is becoming necessary due to global environmental problems. The reforming of light hydrocarbons is a particularly efficient process for producing synthesis gas, H2 and CO, from greenhouse gasses [1]. The steam reforming of methane is the most important method to produce syngas in industry by using a nickel catalyst. Nickel-based catalysts are the conventional catalysts in industrial applications due to their fast turnover rates, good availability, and low costs, however, limited by their tendency towards coke formation. In this study, a detailed surface reaction mechanism is developed for steam reform-ing of methane over nickel and results are compared with the reference data. Y1 - 2022 UR - https://www.researchgate.net/publication/361279412_Thermodynamic_analysis_to_develop_a_detailed_surface_reaction_mechanism ER - TY - GEN A1 - Rakhi, Rakhi A1 - Giri, Binod Raj A1 - Günther, Vivien A1 - Mauss, Fabian T1 - Investigation dry reforming of methane over nickel using a one‐dimensional model T2 - PAMM N2 - In the field of catalysis, dry reforming, that is, methane reforming with CO2, is in the focus due to growing environmental concerns about oil depletion and global warming with a desire to produce synthesis gas. However, this process can lead to the formation of carbon, which can cause catalyst deactivation, especially at industrial conditions. Nevertheless, the key to develop a more coke-resistant catalyst is a better comprehension of the reforming process at a molecular level. Regardless of all the investigations available in literature, the detailed path for the conversion of methane to syngas and carbon remains a controversial issue. Another problem in setting up a reaction mechanism is the difficulty to define the thermodynamic data for intermediate surface species and this leads to the development of thermodynamic consistent surface reaction mechanisms in literature where the thermodynamic data are not used to calculate the rate coefficients of the reverse reactions. Rather the Arrhenius parameters for the forward as well as backward reactions are explicitly given in the reaction mechanism to establish thermodynamic equilibrium. In this investigation, a kinetically consistent detailed surface reaction mechanism is developed which consists of 26 reversible reactions with the help of a one-dimensional model, LOGEcat. Our previous work constructs the basis of the present investigation. Further, a detailed sensitivity analysis of reversible reactions and reaction pathways is performed to understand the mechanism better. The mechanism is validated for dry reforming of methane over nickel catalyst, however, it can also be used for other processes, such as, steam reforming and partial oxidation. The mechanism is tested by comparing the simulation results with the literature experiments and simulations in a wide range of temperature. The new developed kinetically consistent surface reaction mechanism is able to accurately express the dry reforming of methane over the nickel catalyst for complete range of temperature and also provide a useful insight into the key rate determining steps. Y1 - 2023 UR - https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.202300266 U6 - https://doi.org/10.1002/pamm.202300266 VL - 23 IS - 4 ER -