Flow reactor experiments on the selective non-catalytic removal (SNCR) of nitric oxide using a urea-water solution

An experimental investigation on the removal of nitric oxides using an electrically heated, quartz lined, laminar flow reactor was completed at ambient pressure for temperatures between 800 and 1300 K. Exhaust gas was simulated by using mixtures from bottled gases. A solution of urea and water was injected into the simulated exhaust gas. Removal of nitric oxide was observed along with by-products for various inlet oxygen and carbon monoxide concentrations. A Fourier transform infrared (FTIR) spectrometer was used to determine concentrations of all species. Species measured were nitric oxide (NO), nitrogen dioxide (NO 2 ), nitrous oxide (N 2 O), ammonia (NH 3 ), isocyanuric acid (HNCO), carbon monoxide (CO), and carbon dioxide (CO 2 ). Nitric oxide removal was a strong function of temperature and concentrations of oxygen and carbon monoxide. The greatest nitric oxide removal (up to 95%) was achieved for temperatures near 1150 K for 5% oxygen. With oxygen present in the gas composition, NO removal is strongly enhanced for higher CO concentrations below a certain temperature. Above that temperature, carbon monoxide inhibited the removal of nitric oxides. This temperature which caused a significant change of the reaction behavior was dependent on the O 2 concentration. This temperature was identified as 1200 K for 1% O 2 concentration, 1150 K for 5% O 2 concentration, and 1100 K for 15% O 2 concentration.

Flow reactor experiments on the selective non-catalytic removal (SNCR) of nitric oxide using a urea-water solution Academic Article