Modeling Converters during the Warm-up Period for Hydrocarbon Oxidation

Catalytic converters are used for minimizing the release of pollutants to the atmosphere. It is during the warm-up period that hydrocarbons are seen to be released in appreciable quantities from these converters. In this paper the conversion of a fast oxidizing hydrocarbon propylene is analysed using two numerical methods. The quasi steady state method assumes the accumulation terms to be negligible in the gas phase mass and energy balance equations, however this term is present in the solid phase energy balance. The unsteady state model accounts for the accumulation term to be present in the gas phase mass and energy balance and in the solid phase energy balance. The results derived from the two models for gas concentration, gas temperature and solid temperature are compared.

• Sanchita Chauhan
• V.K. Srivastava

• Propylene
• catalyst
• quasi steady state
• unsteady state.

[1] R. Wanker, H. Raupenstrauch, and G. Staudinger, "A Fully Distributed
Model for the Simulation of a Catalytic Combustor", Chem. Eng. Sci.,
vol. 55, pp. 4709-4718, 2000.
[2] R. M. Heck, S. Gulati, and R. J. Farrauto, "The Application of
Monoliths for Gas Phase Catalytic Reactions", Chem. Engng. J, vol.
82, pp. 149-156, 2001.
[3] J. M. Keith, H. C. Chang, and D. T. Leighton Jr., "Designing a Fast
Igniting Catalytic Converter System", AIChE J., vol. 45, pp. 603-614,
March 2001.
[4] W-S. Kim, "A Computational Approach to Modeling the Warm-Up
Behavior of Automotive Catalytic Converter for Reducing Cold -Start
Emissions", Proceedings of the 2nd International Conference on
Computational Heat and Mass Transfer, COPPE/UFRJ - Federal
University of Rio de Janeiro, Brazil, Oct 22-26, 2001.
[5] P. M. Liang, M. D. Shane, S. Son, A. A. Adamczyk, and P. Li, "A
Simplified Approach to Modeling Exhaust System Emissions:
SIMTWC", SAE Paper 1999-01-3476, pp. 1362-1373, 1999.
[6] R. H. Heck, J. Wei, and J. R. Katzer, "Mathematical Modelling of
Monolithic Catalysts", AIChE J., vol. 22, pp. 477-484, 1976.
[7] T. Ahn, W. V. Pinczewski, and D. L. Trimm, "Transient Performance
of Catalytic Combustors for Gas Turbine Applications", Chem. Eng.
Sci., vol. 41, no. 1, pp. 55-64, 1986.
[8] S. Chauhan, and V. K. Srivastava, "Modeling for Propylene and
Propane present in the Exhaust Gases in a Monolithic Catalytic
Converter", Indian Chem. Engr.,vol.60, pp 301-311, 2008.
[9] S. Chauhan, and V. K. Srivastava, "Modeling Exhaust Gas Pollution
Abatement: Part I- Single Hydrocarbon Propylene", Computers and
Mathematics with Applications, vol. 55, pp. 319-330, 2008.