Keywords: air pollution, nitrogen oxides, selective non-catalytic reduction, simulation, urea deNOx, environmental pollution, kinetic modelling, flue gases, NOx removal, isothermal plug flow reactors, modelling
Computational modelling of NOx removal by selective non-catalytic reduction
This paper presents the results of computational kinetic modelling of the removal of nitrogen oxides (NOx) from flue gases by selective non-catalytic reduction (SNCR) process using urea as a reducing agent. CHEMKIN and SENKIN computer codes were used with latest reaction mechanism parameters for simulated conditions in an isothermal plug flow reactor. Flue gas initial conditions were simulated as 70 litres/min propane containing 500 ppm background NOx. A range of molar ratios was studied at optimum temperature. Carbon monoxide and hydrogen were investigated as potential enhancers to lower the temperature window. The modelling results suggested that the optimum temperature for peak reduction was around 1075C with optimum molar ratios of 1.5. Hydrogen was found to be an efficient enhancer. The optimum residence time was found to be about 80 milliseconds.