Selective Catalytic Reduction of NO with Hydrocarbons:  Experimental and Simulation Results

Abstract

The selective catalytic reduction (SCR) of NO was studied over alumina-based catalysts. The experimental data showed that the peak NO conversion and the temperature range where each catalyst exhibits its highest activity depend on the impregnated metal. Kinetic studies were carried out to estimate the apparent order of reaction with respect to the involved gases and the apparent activation energies. The catalytic activity of the alumina-based catalysts was also tested in a fixed-bed reactor unit under various reaction conditions. A mathematical model was applied to reproduce the experimental data using the experimentally determined reaction rate expression. The model predictions were in agreement with the concentrations measured at the exit of the fixed-bed reactor, though no arbitrarily chosen parameters were used in the application of the mathematical model.

Kinetic Investigation of the Selective Catalytic Reduction of Nitric Oxide by Propylene over Pt/Al2O3

“…The presence of NO retards the activation of propylene by 50-70 °C, as can be seen in Figure 2. Similar results have been recently reported for other platinumbased catalysts (Lionta et al, 1996;Amiridis et al, 1997) and suggest that at low temperatures NO blocks the catalyst sites responsible for propylene oxidation. This is consistent with our preliminary infrared studies that show the presence of significant amounts of nitrogencontaining species on the platinum sites under these conditions.…”

“…Given the commercial potential of platinum-based catalysts for HC-SCR, more attention has focused recently on the performance of these catalysts (Obuchi et al, 1993;Burch et al, 1994;Bamwenda et al, 1995;Smedler et al, 1995;Inaba et al, 1995;Burch and Millington, 1996;Burch and Ottery, 1996;Obuchi et al, 1996;Lionta et al, 1996). Still, however, a clear picture of the fundamental surface chemistry involved in this reaction has not been developed.…”

Selective Catalytic Reduction of NOx by Hydrocarbons/Oxygenates. Application for the Control of NOx from the Regenerator of a Fluid Catalytic Cracking Pilot-Plant Unit

“…The Rh/alumina catalyst was activated at lower temperatures than alumina and exhibited higher reaction rates at this temperature range. Our previous studies showed that unpromoted γ-alumina activates C 3 H 6 at high temperatures (ca. 500 °C).…”

Novel bifunctional catalytic systems for the SCR of NOx using hydrocarbons as reductants: Step one, NO oxidation

“…Details of the reaction unit can be found elsewhere (Lionta et al, 1996). All experiments took place in a quartz flow reactor of 2 cm o.d.…”