Modeling of Dual Layer Ammonia Slip Catalysts (ASC)



SAE 2012 World Congress & Exhibition
Authors Abstract
In recent years, ammonia slip catalysts (ASC) are being used downstream of an SCR system to minimize the ammonia slip. The dual-layer ASC is more attractive for its bi-functionality in reducing the ammonia and NOX emissions. It consists of two layers with the upper layer comprising a component with SCR functionality and the lower layer a PGM containing catalyst with oxidation functionality. Thus, both oxidation and SCR reactions take place in two different layers and are interlinked by the inter-layer mass transfer mechanism. In addition, adsorption and desorption kinetics between the gas and solid phases play a significant role. Mathematically, the overall system is a complex system of mass, momentum and energy transfer equations with temporal and spatial variables in both axial and radial directions. In this work, we focus on devising a suitable, computationally inexpensive model for such ASCs to be efficiently used for design, control and system optimization studies. We discuss a 1D+1D (Pseudo 2D) model capturing the above-mentioned mechanisms to different extents and investigate the accuracy of the model in both steady state and transient modes. Extensive model validation has been carried out against Cu-ASC reactor and engine data; good agreement between the model predictions and the experimental results was achieved.
Meta TagsDetails
Sukumar, B., Dai, J., Johansson, A., Markatou, P. et al., "Modeling of Dual Layer Ammonia Slip Catalysts (ASC)," SAE Technical Paper 2012-01-1294, 2012,
Additional Details
Apr 16, 2012
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Content Type
Technical Paper