Johar, Jasmeet Singh (2005-08). An experimental investigation of the urea-water decomposition and selective catalytic reduction (SCR) of nitric oxides with urea using V2O5-WO3-TiO2 catalyst.. Master's Thesis. Thesis uri icon

abstract

  • Two flow reactor studies, using an electrically heated laminar flow reactor over Vanadia based (V2O5-WO3/TiO2) honeycomb catalyst, were performed at 1 atm pressure and various temperatures. The experiments were conducted using simulated exhaust gas compositions for different exhaust gases. A quartz tube was used in order to establish inert conditions inside the reactor. The experiments utilized a Fourier transform infrared (FTIR) spectrometer in order to perform both qualitative and quantitative analysis of the reaction products. Urea-water solution decomposition was investigated over V2O5-WO3/TiO2 catalyst over the entire SCR temperature range using the temperature controlled flow reactor. The solution was preheated and then injected into pure nitrogen (N2) stream. The decomposition experiments were conducted with a number of oxygen (O2) compositions (0, 1, 10, and 15%) over the temperature range of 227oC to 477oC. The study showed ammonia (NH3), carbon-dioxide (CO2) and nitric oxide (NO) as the major products of decomposition along with other products such as nitrous oxide (N2O) and nitrogen dioxide (NO2). The selective catalytic reduction (SCR) of nitric oxide (NO) with urea-water solution over V2O5-WO3/TiO2 catalyst using a laboratory laminar-flow reactor was investigated. Urea-water solution was injected at a temperature higher than the vaporization temperature of water and the flow reactor temperature was varied from 127oC to 477oC. A FTIR spectrometer was used to determine the concentrations of the product species. The major products of SCR reduction were NH3, NO and CO2 along with the presence of other minor products NO2 and N2O. NO removal of up to 87% was observed. The aim of the urea-water decomposition experiments was to study the decomposition process as close to the SCR configuration as possible. The aim of the SCR experiments was to delineate the effect of various parameters including reaction temperature and O2 concentration on the reduction process. The SCR investigation showed that changing parameter values significantly affected the NO removal, the residual NH3 concentration, the temperature of the maximum NO reduction, and the temperature of complete NH3 conversion. In the presence of O2, the reaction temperature for maximum NO reduction was 377?C for ratio of 1.0.
  • Two flow reactor studies, using an electrically heated laminar flow reactor over
    Vanadia based (V2O5-WO3/TiO2) honeycomb catalyst, were performed at 1 atm pressure
    and various temperatures. The experiments were conducted using simulated exhaust gas
    compositions for different exhaust gases. A quartz tube was used in order to establish
    inert conditions inside the reactor. The experiments utilized a Fourier transform infrared
    (FTIR) spectrometer in order to perform both qualitative and quantitative analysis of the
    reaction products.
    Urea-water solution decomposition was investigated over V2O5-WO3/TiO2 catalyst
    over the entire SCR temperature range using the temperature controlled flow reactor.
    The solution was preheated and then injected into pure nitrogen (N2) stream. The decomposition
    experiments were conducted with a number of oxygen (O2) compositions (0,
    1, 10, and 15%) over the temperature range of 227oC to 477oC. The study showed ammonia
    (NH3), carbon-dioxide (CO2) and nitric oxide (NO) as the major products of decomposition
    along with other products such as nitrous oxide (N2O) and nitrogen dioxide
    (NO2).
    The selective catalytic reduction (SCR) of nitric oxide (NO) with urea-water solution
    over V2O5-WO3/TiO2 catalyst using a laboratory laminar-flow reactor was investigated.
    Urea-water solution was injected at a temperature higher than the vaporization
    temperature of water and the flow reactor temperature was varied from 127oC to 477oC.
    A FTIR spectrometer was used to determine the concentrations of the product species. The major products of SCR reduction were NH3, NO and CO2 along with the presence
    of other minor products NO2 and N2O. NO removal of up to 87% was observed.
    The aim of the urea-water decomposition experiments was to study the decomposition
    process as close to the SCR configuration as possible. The aim of the SCR experiments
    was to delineate the effect of various parameters including reaction temperature
    and O2 concentration on the reduction process. The SCR investigation showed that
    changing parameter values significantly affected the NO removal, the residual NH3 concentration,
    the temperature of the maximum NO reduction, and the temperature of complete
    NH3 conversion. In the presence of O2, the reaction temperature for maximum NO
    reduction was 377?C for ratio of 1.0.

publication date

  • August 2005