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Kinetic Study of Selective Catalytic Reduction of over a Cu/Zeolite Catalyst for Emission Control from Diesel Engines

Nozari, Sara | 2024

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 57532 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Hamzehlouyan, Tayebeh
  7. Abstract:
  8. Urban air pollution has become a significant environmental concern in recent times. NOx recognized as a criterion pollutant, is especially problematic. In 2021, the Tehran Air Quality Control Company reported that the ambient concentration of NOx in Tehran was around 50 ppb, which surpasses both the initial and final targets recently established by the World Health Organization (40 ppb and 10 ppb, respectively). To control and predict NOx emissions from diesel engines, A detailed selective catalytic reduction (SCR) model has been developed to describe the global kinetic reactions within the catalyst. This model incorporates two types of sites for high- and low-temperature NH3 adsorption/desorption and low-temperature H2O storage. It addresses the formation of ammonium nitrate during fast SCR, the decomposition of ammonium nitrate without NO, and the reactions of N2O with NO and NO2 in the presence of NH3. The system is considered isothermal due to the low enthalpy of reactions in the SCR system. In developing the equations, mass transfer from the bulk of gas to the solid phase and within the solid phase was considered, as well as surface coverages. The model has been validated with Cu-ZSM5 data, covering NOx conversion under steady-state conditions. Additionally, the model examines the impact of the inlet gas composition, including the NH3/NO ratio, space velocity, O2 concentration, and H2O concentration. The results are consistent with those obtained from previous studies demonstrating the SCR model can accurately estimate emissions under steady-state conditions, help understand the impact of SCR reaction mechanisms and assist in designing and optimizing SCR catalysts for improving engine fuel economy and emissions control technologies
  9. Keywords:
  10. Selective Catalytic Reduction (SCR) ; Kinetics Study ; Modeling ; Nitrogen Oxide Emission ; Cupper/Zeolite Catalyst ; Mitigation ; Diesel Engines

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