Removal of NO in NO/N₂, NO/N₂/O₂, NO/CH₄/N₂, and NO/CH₄/O₂/N₂ Systems by Flowing Microwave Discharges

Abstract

In this paper, continuing previous work, we report on experiments carried out to investigate the removal of NO from simulated flue gas in nonthermal plasmas. The plasma-induced decomposition of small concentrations of NO in N2 used as the carrier gas and O2 and CH4 as minority components has been studied in a surface wave discharge induced with a surfatron launcher. The reaction products and efficiency have been monitored by mass spectrometry as a function of the composition of the mixture. NO is effectively decomposed into N2 and O2 even in the presence of O2, provided always that enough CH4 is also present in the mixture. Other majority products of the plasma reactions under these conditions are NH3, CO, and H2. In the absence of O2, decomposition of NO also occurs, although in that case HCN accompanies the other reaction products as a majority component. The plasma for the different reaction mixtures has been characterized by optical emission spectroscopy. Intermediate excited species of NO*, C*, CN*, NH*, and CH* have been monitored depending on the gas mixture. The type of species detected and their evolution with the gas composition are in agreement with the reaction products detected in each case. The observations by mass spectrometry and optical emission spectroscopy are in agreement with the kinetic reaction models available in literature for simple plasma reactions in simple reaction mixtures.

Photochemical removal of NO2 by using 172-nm Xe2 excimer lamp in N2 or air at atmospheric pressure

“…Removal of NOx was also studied by using pulsed corona discharge [6][7][8][9][10][11][12][13] and microwave discharge methods [14][15][16][17][18][19][20][21][22][23]. Discharge methods will become a low cost convenient method, if NOx can be removed without using any catalysts and reducing agents.…”

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

“…Baeva et al [234,235] also found the same phenomenon when he decomposed NO x by pulsed microwave discharge plasma at atmospheric pressure. Hueso et al [236,237] used microwave-induced plasma to study the decomposition of NO in Ar and N 2 . In the presence of oxygen, if enough reductive gases were added, the decomposition of NO was still dominant.…”

Anisotropic Au-ZnO photocatalyst for the visible-light expanded oxidation of n-hexane

“…Further research is still necessary to implement disruptive improvements that can pave the way for the regular use of solar light and/or low consumption artificial lights (i.e. Light-emitting diodes-LEDs, novel reactor configurations and so on) [9,10,[12][13][14][16][17][18][19][20][21][22][23][24][25]. In addition, it is also necessary to boost the development of novel photocatalytic materials that can overcome the inherent burdens of TiO2 and are able to take advantage of the full solar spectrum instead of the limited UV range attributed to TiO2 [26][27][28][29][30][31][32][33][34].…”