Översikt
- Datum:Startar 5 March 2026, 10:00Slutar 5 March 2026, 13:00
- Plats:Scaniasalen, Chalmersplatsen 1, Chalmers
- Opponent:Prof. Enrico Tronconi, Department of Energy, Politecnico di Milano, Italy
- AvhandlingLäs avhandlingen (Öppnas i ny flik)
Combustion engines will remain important in heavy-duty transport for years, especially in long-haul and marine shipping. During this transition, emission aftertreatment is one of the fastest ways to reduce harmful pollutants from vehicles already in use. Stricter regulations (such as Euro 7 and EPA 27) demand low emissions during rapid transients and across a wide operating range with detailed monitoring strategies.
To meet this challenge, mechanistic catalyst models are essential. By embedding physics and chemistry in the model structure, they provide insight, transparency, and better control than purely black-box approaches. They also enable hybrid strategies that combine physical modelling with data-driven methods, while keeping a clear link to real mechanisms and parameters.
This thesis advances modelling for Selective Catalytic Reduction (SCR) catalysts in lean-burn engines, focusing on vanadium-based NH3-SCR and Pd-based H2-SCR. The work targets both mechanistic understanding and model quality. A workflow is developed from experiments to validated models: reactor characterization to correct dispersion and delay effects, steady-state analysis to create model structures using a data-driven framework, and model discrimination to reduce overfitting and parameter correlation.
For vanadium-based NH3-SCR, experiments and modelling are combined to capture NH3 adsorption and internal mass transfer in a monolith reactor. Model structures are treated as variables and optimized with a custom algorithm, supported by new objective functions that improve robustness. The final model identifies five Langmuir-type NH3 adsorption sites with different behavior to temperature and water. Steady-state parameters are linked to thermodynamic properties, strengthening physical meaning and parameter validity. Internal mass transfer is assessed using two washcoat formulations and by considering non-square channels. The result is a compact, detailed model that captures key SCR dynamics and improves prediction of transient responses across wide conditions.
For Pd-based H2-SCR aimed at lean H2 engines, 1 wt% Pd catalysts on Al2O3, TiO2, BEA zeolite, and SSZ-13 zeolite are tested from 100–300°C under varying H2/NO ratios in dry and wet conditions. Pd/TiO2 gives the highest NO conversion and N2 yield, consistent with material characterization. A kinetic model coupled with mass transfer simulates NO reduction to N2, N2O, and NH3, together with H2 oxidation, and reproduces trends for all supports. NH3 forms only on Pd/TiO2, while N2O forms on all supports and is unaffected by water concentration. External mass transfer is shown to limit fast H2 oxidation, increasing H2 available for NO reduction.
To meet this challenge, mechanistic catalyst models are essential. By embedding physics and chemistry in the model structure, they provide insight, transparency, and better control than purely black-box approaches. They also enable hybrid strategies that combine physical modelling with data-driven methods, while keeping a clear link to real mechanisms and parameters.
This thesis advances modelling for Selective Catalytic Reduction (SCR) catalysts in lean-burn engines, focusing on vanadium-based NH3-SCR and Pd-based H2-SCR. The work targets both mechanistic understanding and model quality. A workflow is developed from experiments to validated models: reactor characterization to correct dispersion and delay effects, steady-state analysis to create model structures using a data-driven framework, and model discrimination to reduce overfitting and parameter correlation.
For vanadium-based NH3-SCR, experiments and modelling are combined to capture NH3 adsorption and internal mass transfer in a monolith reactor. Model structures are treated as variables and optimized with a custom algorithm, supported by new objective functions that improve robustness. The final model identifies five Langmuir-type NH3 adsorption sites with different behavior to temperature and water. Steady-state parameters are linked to thermodynamic properties, strengthening physical meaning and parameter validity. Internal mass transfer is assessed using two washcoat formulations and by considering non-square channels. The result is a compact, detailed model that captures key SCR dynamics and improves prediction of transient responses across wide conditions.
For Pd-based H2-SCR aimed at lean H2 engines, 1 wt% Pd catalysts on Al2O3, TiO2, BEA zeolite, and SSZ-13 zeolite are tested from 100–300°C under varying H2/NO ratios in dry and wet conditions. Pd/TiO2 gives the highest NO conversion and N2 yield, consistent with material characterization. A kinetic model coupled with mass transfer simulates NO reduction to N2, N2O, and NH3, together with H2 oxidation, and reproduces trends for all supports. NH3 forms only on Pd/TiO2, while N2O forms on all supports and is unaffected by water concentration. External mass transfer is shown to limit fast H2 oxidation, increasing H2 available for NO reduction.
Andres Felipe Suarez Corredor
- Doktorand, Kemiteknik, Kemi och kemiteknik