@misc{PasternakSiddareddydeSyniawaetal., author = {Pasternak, Michał and Siddareddy, Reddy Babu and de Syniawa, Larisa Le{\´o}n and Guenther, Vivien and Picerno, Mario and Andert, Jakob and Franken, Tim and Mauss, Fabian and Adamczyk, Wojciech}, title = {Plant modelling of engine and aftertreatment systems for X-in-the-loop simulations with detailed chemistry}, series = {CONAT 2024 International Congress of Automotive and Transport Engineering.}, journal = {CONAT 2024 International Congress of Automotive and Transport Engineering.}, publisher = {Springer Nature Switzerland}, address = {Cham}, isbn = {978-3-031-77626-7}, doi = {10.1007/978-3-031-77627-4_14}, pages = {151 -- 163}, abstract = {Use of numerical simulations at early stage of engine and aftertreatment systems development helps in evaluating their different concepts and reducing the need for costly building of prototypes. In this work, we explore the feasibility of fully physical and chemical-based tool-chain for co-simulating engine in-cylinder and aftertreatment processes. Detailed gas-phase reaction kinetics and surface chemistry mechanisms are applied for the modeling of combustion, pollutants formation and aftertreatment, respectively. Engine in-cylinder performance parameters are simulated using a stochastic reactor model and multi-component fuel surrogate. The engine model is coupled with an aftertreatment model capable of simulating diesel oxidation catalyst (DOC), selective catalytic reduction catalyst, lean NOx trap, ammonia slip catalyst, and three-way catalyst. Both the engine and aftertreatment models are embedded within the Simulink framework. They work in co-simulation and are coupled using Functional Mock-up Interface (FMI) technology. The coupled framework acts as a virtual test bench that is developed given its application for X-in-the-Loop (XiL) simulations. The framework can be applied to engine steady state or transient operating conditions. Here, exemplary calculations are performed using a Model-in-the-Loop (MiL) approach. Simulations are conducted under transient conditions of Worldwide Harmonized Light Vehicle Test Cycle for a compression ignition engine coupled with a DOC. The presented framework is considered a first step towards complex engine plant modeling using detailed chemistry for the virtualization of the development of engine, fuels and aftertreatment systems.}, language = {en} } @misc{MaussRakhi, author = {Mauss, Fabian and Rakhi, Rakhi}, title = {Numerical study of catalytic methanation reactions using a kinetic model}, series = {SAE Technical Paper}, journal = {SAE Technical Paper}, number = {2024-24-0022}, issn = {0148-7191}, doi = {10.4271/2024-24-0022}, pages = {5}, abstract = {Even if huge efforts are made to push alternative mobility concepts, such as, electric cars (BEV) and fuel cell powered cars, the importance and use of liquid fuels is anticipated to stay high during the 2030s. The biomethane and synthetic natural gas (SNG) might play a major role in this context as they are raw material for chemical industry, easy to be stored via existing infrastructure, easy to distribute via existing infrastructure, and versatile energy carrier for power generation and mobile applications. Hence, biomethane and synthetic natural gas might play a major role as they are suitable for power generation as well as for mobile applications and can replace natural gas without any infrastructure changes. In this paper, we aim to understand the direct production of synthetic natural gas from CO2 and H2 in a Sabatier process based on a thermodynamic analysis as well as a multi-step kinetic approach. For this purpose, we thoroughly discuss CO2 methanation to control emission in order to maximize the methane formation and minimize the CO formation and to understand the complex methanation process. We have considered an equilibrium and kinetic modelling study on the NiO-SiO2 catalyst for methanation focusing on CO2 derived SNG. In this work, a comprehensive thermodynamic analysis of CO2 hydrogenation is preformed to define the optimum process parameters followed by the kinetic simulations. Further, the simulations can be performed at various conditions, for example, catalyst mass, mass flow, pressure, temperature etc. to optimize the methanation process.}, language = {en} } @misc{MaussRakhi, author = {Mauss, Fabian and Rakhi, Rakhi}, title = {Numerical investigation of equilibrium and kinetic aspects for hydrogenation of CO2}, series = {Catalysts}, volume = {14}, journal = {Catalysts}, publisher = {MDPI}, doi = {10.3390/catal14090562}, pages = {1 -- 20}, abstract = {Even if huge efforts are made to push alternative mobility concepts, such as electric cars and fuel-cell-powered cars, the significance and use of liquid fuels is anticipated to stay high during the 2030s. Biomethane and synthetic natural gas (SNG) might play a major role in this context, as they are raw material for chemical industry that is easy to be stored and distribute via existing infrastructure, and are a versatile energy carrier for power generation and mobile applications. Since biomethane and synthetic natural gas are suitable for power generation and for mobile applications, they can therefore replace natural gas without any infrastructure changes, thus playing a major role.In this paper, we aim to comprehend the direct production of synthetic natural gas from CO2 and H2 in a Sabatier process based on a thermodynamic analysis as well as a multi-step kinetic approach. For this purpose, we thoroughly discuss CO2 methanation to control emissions in order to maximize the methane formation along with minimizing the CO formation and to understand the complex methanation process. We consider an equilibrium and kinetic modeling study on the NiO-SiO2 catalyst for methanation focusing on CO2-derived SNG. The thermodynamic analysis of CO2 hydrogenation is preformed to define the optimal process parameters followed by the kinetic simulations for catalyst development. The investigation presented in this paper can also be used for developing machine learning algorithms for methanation processes.}, language = {en} } @misc{SabiaMannaMaussetal., author = {Sabia, Pino and Manna, M.V. and Mauss, Fabian and Ragucci, R.}, title = {MILD Combustion stabilization issues through the analysis of hysteresis behaviors : the case of new energy carriers}, series = {Applications in Energy and Combustion Science}, volume = {19}, journal = {Applications in Energy and Combustion Science}, number = {September 2024}, doi = {10.1016/j.jaecs.2024.100276}, pages = {13}, abstract = {MILD combustion processes are renewed to reveal a strong resilience to extinction phenomena and/or instabilities, whereas the oxidation process is stabilized trough ignition phenomena. Under MILD conditions, igni-diffusive and/or perfectly mixed kernels, forming during the mixing process between hot products and fresh reactants, are so much diluted and pre-heated to escape classical feed-back flammable flames stabilization mechanisms, while ignition and extinction events merge in a unique condition through "anhysteretic" behaviors. So far, considering methane as reference fuel, it has been largely demonstrated the mentioned "anhysteretic" condition is very conservative and defines a sub-domain of MILD combustion processes, following Cavaliere and de Joannon's definition. Furthermore, the coincidence of ignition and extinction phenomena can occur also preserving hysteresis phenomena. In turns, this condition strongly enlarges the stabilization domain of MILD combustion processes, starting from the upper branch of the hysteresis behaviors to the real extinction, with characteristic unstable loci to consider as further/last opportunity to promote stable operative conditions through the formation of local thermo-kinetic conditions in the combustion chamber during hot products/fresh reactants mixing process (injection configuration/burner design), or by forced ignition events. The hysteresis behaviors of renewable/alternative fuels, relevant within the decarbonization policies of several energy sectors, are thoroughly discussed under MILD conditions through numerical studies in model reactors in order to shed light on common and/or different features, and outline practical rules towards the definition of stable MILD combustion domains. Results show that, as MILD combustion is a chemical kinetics-driven processes, stability issues have to be discussed in relation to fuel nature, albeit with common behavior can be derived. The coincidence between extinction/ignition phenomena is reached for extremely diluted conditions, already ascribable to MILD combustion conditions, thus defining a small sub-domain of the process. This condition can be reached through "hysteretic" or "anhysteretic" behaviors.}, language = {en} } @misc{VadivalaFrankenThapaetal., author = {Vadivala, Monang and Franken, Tim and Thapa, Ashish and Mauss, Fabian}, title = {Evaluation of metamodels for prediction of species concentration and reactor outlet temperature of Sabatier reactor}, abstract = {The production of green gases using Power-to-gas in industry and the energy sector is essential for reducing the carbon footprint. In this process, green hydrogen and carbon dioxide are converted into synthetic methane using nickel (Ni) catalysts. A one-dimensional (1D) model of a Sabatier reactor enables the simulation of transport processes in the porous medium and reaction kinetics on the Ni/Al2O3 catalyst.}, language = {en} } @misc{RakhiShresthaGuentheretal., author = {Rakhi, Rakhi and Shrestha, Krishna Prasad and G{\"u}nther, Vivien and Mauß, Fabian}, title = {Kinetically consistent detailed surface reaction mechanism for steam reforming of methane over nickel catalyst}, series = {Reaction Kinetics, Mechanisms and Catalysis}, volume = {135}, journal = {Reaction Kinetics, Mechanisms and Catalysis}, number = {6}, issn = {1878-5204}, doi = {10.1007/s11144-022-02314-7}, pages = {3059 -- 3083}, language = {en} } @misc{RakhiMauss, author = {Rakhi, Rakhi and Mauss, Fabian}, title = {Thermodynamic model : steam and oxidative reforming of methane over nickel catalyst}, series = {Reaction Kinetics, Mechanisms and Catalysis}, volume = {137}, journal = {Reaction Kinetics, Mechanisms and Catalysis}, number = {2}, publisher = {Springer}, doi = {10.1007/s11144-024-02571-8}, pages = {791 -- 812}, abstract = {In this paper, we have used a thermodynamic model for the first time to investigate the steam and oxidative reforming of methane over a nickel catalyst in a wide temperature range, i.e., 400-1200 K. The available literature focus on the kinetic models and hence, thermodynamic models require attention to understand the behaviour of the thermochemistry of the species involved in the mechanism. This study presents the comparison between the species concentration produced using the thermodynamic model against the available kinetic model to validate the results. The investigation is further extended, firstly, to perform the sensitivity analysis of the reactions involved in a thermodynamic model to figure out the most influential reactions at various temperatures and pressures. This allows us to compare the most influencing reactions in reforming process for kinetic and thermodynamic model to optimize the processes. Secondly, the reaction flow analysis is carried out for the thermodynamic model to comprehend the effect of the thermochemistry of the species and the major difference in the reaction pathways for both the models are noted.}, language = {en} } @misc{RakhiMauss, author = {Rakhi, and Mauss, Fabian}, title = {Optimising production of synthetic natural gas (SNG) from methane synthesis}, series = {Proceedings in applied mathematics and mechanics : PAMM}, volume = {25}, journal = {Proceedings in applied mathematics and mechanics : PAMM}, number = {1}, publisher = {Wiley-VCH GmbH}, address = {Weinheim}, issn = {1617-7061}, doi = {10.1002/pamm.202400044}, pages = {1 -- 5}, language = {en} } @misc{ShresthaMaiGirietal., author = {Shrestha, Krishna Prasad and Mai, Tam V.-T. and Giri, Sushant and Reddy, V. Mahendra and Szőri, Mil{\´a}n and Verma, Rakhi and Mauss, Fabian and Giri, Binod Raj and Huynh, Lam Kim}, title = {Reaction kinetics of NH₂ with H₂CO and CH₃CHO : modeling implications for NH₃-dual fuel blends}, series = {International journal of chemical kinetics}, volume = {57}, journal = {International journal of chemical kinetics}, number = {7}, publisher = {Wiley}, address = {New York}, issn = {0538-8066}, doi = {10.1002/kin.21781}, pages = {403 -- 416}, abstract = {Carbon-free fuels like ammonia (NH₃) and hydrogen (H₂) offer significant potential in combating global warming by reducing greenhouse gas emissions and moving toward zero carbon emissions. Over the past few years, our research has focused on understanding the combustion behavior of carbon-neutral and carbon-free fuels. In particular, we have explored the combustion characteristics of NH₃ when blended with various hydrocarbons and oxygenates. Our investigation revealed that carbon-nitrogen cross-chemistry plays a crucial role in shaping the combustion properties of NH3-hydrocarbon/oxygenate blends. Specifically, the chemistry of amino (NH₂) radicals is vital in influencing the low-temperature reactivity of these blends. Understanding the interactions between carbon and nitrogen is essential for optimizing combustion processes and improving the emissions profile of NH₃-based fuels. Recognizing the significance of this cross-chemistry, we investigated the reaction kinetics of NH₂ radicals with formaldehyde (H₂CO) and acetaldehyde (CH₃CHO) using high-level ab initio and transition state theory calculations. We computed the potential energy profiles of these reactions at the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ level of theory to analyze the reactivity of NH2 radicals at various C─H bond sites. The newly derived rate constants have proven to be highly sensitive for modeling the low-temperature oxidation of NH₃-dual fuel blends, significantly enhancing the predictive accuracy of our previously published kinetic models. This work offers valuable insights into the role of NH₂ radicals, thereby advancing the development of NH₃-dual fuel systems.}, language = {en} } @misc{GiriMaiShresthaetal., author = {Giri, Binod Raj and Mai, Tam V.-T. and Shrestha, Krishna Prasad and Giri, Sushant and Naik, R. Thirumaleswara and Verma, Rakhi and Mauss, Fabian and Huynh, Lam K.}, title = {Theoretical kinetic study of NH₂ reactions with dimethyl ether and diethyl ether : implications for kinetic modeling}, series = {International journal of chemical kinetics}, volume = {57}, journal = {International journal of chemical kinetics}, number = {6}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {0538-8066}, doi = {10.1002/kin.21779}, pages = {353 -- 363}, abstract = {Ammonia (NH₃) and hydrogen (H₂) have emerged as promising carbon-free fuels to help mitigate global warming by reducing greenhouse gas emissions. Our ongoing research currently focuses on understanding the combustion characteristics of NH₃ blends with oxygenates and hydrocarbons, uncovering the critical role of carbon-nitrogen cross-reactions in accurately modeling their combustion behavior. Amino (NH₂) radicals, which are abundant in ammonia and nitrogen-rich environments, strongly influence the low-temperature reactivity of NH₃-hydrocarbon/oxygenate mixtures, affecting overall reactivity and emission characteristics. Recognizing the importance of NH₂ radicals, we investigated the reaction kinetics of NH₂ with dimethyl ether (DME, CH₃OCH₃) and diethyl ether (DEE, CH₃CH₂OCH₂CH₃) using appropriate high-level ab initio and statistical rate theory methods. We computed the potential energy profiles at the CCSD(T)/cc-pV(T, Q)Z//M06-2X/aug-cc-pVTZ level of theory, analyzing the reactivity of NH₂ radicals at various C─H sites of these diethers. Incorporating these newly derived rate parameters, our updated kinetic model successfully captures previous experimental data, addressing the modeling challenges encountered in our earlier studies. Our findings, including insights into the impact of NH₂ radicals, contribute to an understanding of ammonia combustion and its potential in achieving carbon-neutral energy systems.}, language = {en} } @misc{WernerKimMauss, author = {Werner, Adina and Kim, Jongmin and Mauss, Fabian}, title = {Pressure and temperature dependent UNIQUAC model for methanol - water mixtures}, series = {Fluid phase equilibria : an international journal}, volume = {599}, journal = {Fluid phase equilibria : an international journal}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {0378-3812}, doi = {10.1016/j.fluid.2025.114533}, pages = {1 -- 13}, abstract = {A pressure dependency is included in a quadratic temperature dependent binary interaction parameter of the UNIQUAC model. The obtained activity coefficients for methanol-water mixtures are compared with only temperature dependent UNIQUAC and UNIFAC, and with calculated activity coefficients based on experimental data between 298.15 - 373.15 K and 0.1519 - 1.01325 bar produced with vapor-liquid equilibrium calculations and Wilson method. This model exhibits an overall good agreement. The predicted activity coefficients are more adaptable than those from models without pressure dependence, indicating potential for further improvement.}, language = {en} }