A Global Kinetic Model for a Modern DOC Incorporating Mechanisms for Sulfur Poisoning and Reverse Hysteresis

Mohit  Gayatri, Gamma Technologies LLC

Mohit Gayatri*, Ryan Dudgeon*, Dominik Artukovic*, and Chaitanya Sampara#

*Gamma Technologies LLC, # Viridis Chemicals

A comprehensive global kinetics model that incorporates the effects of sulfur poisoning and reverse hysteresis in a modern diesel oxidation catalyst (DOC) is presented. A detailed test protocol consisting of commonly observed species in a DOC viz. CO, C3H6, C10H22, NO, and NO2 was first designed. Synthetic gas bench (SGB) measurements were conducted based on the prescribed test protocol to capture hydrocarbon storage and oxidation of the all the relevant species of interest. As a first step towards modeling, a global kinetics model was generated and validated for these oxidation and storage kinetics, based on the reaction mechanism proposed by Millo et al. [1]. Next, a sulfur poisoning model based on the work of Hamzehlouyan et al. [2] was integrated with the oxidation kinetics to predict the effect of sulfur on DOC performance. Finally, an additional set of reaction steps based on previously reported literature [3, 4] were incorporated with the global kinetics developed as part of this work to account for the platinum oxide reverse hysteresis phenomenon. Parametric studies using the newly developed model were conducted to assess the effect of sulfur in the exhaust stream and the effect of reverse hysteresis during the start-up (heat-up) and shut-down (cool-down) phases of a DOC.

References:

  1. Millo, F., Rafigh, M., Sapio, F., Barrientos, E.J. et al., “Application of Genetic Algorithm for the Calibration of the Kinetic Scheme of a Diesel Oxidation Catalyst Model,” SAE Technical Paper 2018-01-1762, 2018, doi:10.4271/2018-01-1762.
  2. Hamzehlouyan, C. S. Sampara, J. Li, A. Kumar, W.S. Epling, “Experimental and kinetic study of SO2 oxidation on a Pt/γ-Al2O3 catalyst”, Appl. Catal. B, Vol. 152-153, 2014, p. 108-116, doi:10.1016/j.apcatb.2014.01.005.
  3. “Reversible Activation/Deactivation Effects,” Votsmeier, M., CLEERS Workshop 2014, https://cleers.org/wp-content/uploads/formidable/3/2014CLEERS_Votsmeier.pdf.
  4. “Inverse Hysteresis During the NO Oxidation on Pt under Lean Conditions,” Hauptmann, W., Votsmeier, M., Gieshoff, J., Drochner, A., Vogel, H., 2009, Applied Catalysis B: Environmental, v93, p22-29.