Effect of water vapor and hydrocarbons in removing NOx by using nonthermalplasma and catalyst

Removal of NOx in flue gas was investigated by using nonthermal plasma with catalysts. In this experiment, flue gas contained 5%-15% water vapor and h ydrocarbons, as well as nitrogen, oxygen, and carbon dioxide. Catalysts tes ted in this paper were copper- and sodium-coated zeolite (CuZSM-5, NaZSM-5) and a conventional three-way catalyst (Pt-Rh, alumina cordierite). The sim ulated flue gases had from 0% to 15% water vapor. 70% NO removal was achiev ed with NaZSM-5 catalyst at 200 degreesC-500 degreesC, with 10% moisture an d the power to the reactor turned off. High-temperature removal of NOx was the result of plasma chemical reactions and adsorption in the catalyst. How ever, nonthermal plasma degrades the NOx removal with CuZSM-5 catalyst, whe n the gas temperature is 300 degreesC or above. When the gas temperature wa s 100 degreesC, the nonthermal plasma process was enhanced by the combinati on of nonthermal plasma with any type of catalyst. The catalysts investigat ed in this paper do not work at lower temperatures by themselves. Adsorptio n characteristics were also investigated and only NaZSM-5 catalyst showed s ignificant adsorption.