EFFECT OF OXYGEN ON NO_xREMOVAL IN CORONA DISCHARGE FIELD: NO_xBEHAVIOR WITHOUT A REDUCING AGENT

Abstract

A DeNO x process using a DC corona discharge was investigated experimentally. A mixture system of N 2 =O 2 =NO was used as a test gas. The compositions such as NO, NO 2 , N 2 O and so on were analyzed with Fourier transform infrared spectroscopy and an NO x meter. It was found that the characteristics of NO removal by corona discharge differed remarkably whether or not oxygen exists in the mixture. In regard to the spectrum of light emission from the corona discharge in N 2 atmosphere or N 2 =O 2 mixture, some N 2 bands were detected. N 2 dissociation into atomic N and N 2 radical in the corona discharge field was conjectured. Furthermore, ozone was yielded by the corona discharge in the case of the N 2 =O 2 mixture. Ozone gas from an ozonizer was added into the N 2 =O 2 mixture without corona discharge to investigate the effect of O 3 on the characteristics of NO x removal by corona discharge. In the case of the N 2 =NO mixture, the process of NO reduction was mainly controlled by N 2 radicals excited by the corona discharge. On the other hand, in the case of the N 2 =O 2 =NO mixture, NO was oxidized by ozone generated from the corona discharge and converted to NO 2 and N 2 O 5 .

Influence of non-thermal plasma after-treatment technology on diesel engine particulate matter composition and NOx concentration

“…Therefore, plasma has not been powerful enough to make any significant variation in nitrogen oxide concentrations before this point. It was found that NO is oxidised to NO 2 due to the existence of different active oxygen species and ozone as it is reported on previous studies (Mohapatro and Rajanikanth 2011;Arai et al 2004;Fitzsimmons et al 1999). NO concentration decreased by 72 % and NO 2 concentration increased by 77 % by applying maximum voltage at 13.5 kV during the experiments.…”

“…Furthermore, emission reduction in diesel engines at low temperature is important in some special applications of diesel engines such as mining industries where exhaust cooling occurs for safety reasons. In comparison with the numerous publications on NO x treatment by plasma (Lebouvier et al 2011;Vinh et al 2012;Arai et al 2004;Jolibois et al 2012;Mohapatro and Rajanikanth 2011;Chae 2003;Yoshida et al 2009), a limited amount of research has investigated particulate matter (Ye et al 2005;Thomas et al 2000;Babaie et al 2013) and most of it has emphasised PM mass reduction only (Yao et al 2006;Fushimi et al 2008). In this paper, the effect of plasma technique on particulate matter constitutes (soot, SOF and sulphates) and NO, NO 2 and N 2 O emission concentrations have been studied.…”

Performance evaluation of non-thermal plasma on particulate matter, ozone and CO2 correlation for diesel exhaust emission reduction

“…In addition, ozone will be consumed through different reactions in plasma state. For example, the ozone will be consumed by the following reactions for NO x reduction in plasma exhaust treatment [13,32]: Note that the atomic nitrogen (N) can be produced due to the dissociation of nitrogen and/or NO molecules by high energy electrons in plasma state [3] and NO 3 , which is an unstable compound, usually turns into NO and NO 2 in the environment [33].…”

“…Ozone can participate in many reactions in plasma treated gas. The main reaction for ozone production in the plasma state is the reaction of the O radical with oxygen, based on the following reaction [32]:…”

Experimental study of NO2 reduction in N2/Ar and O2/Ar mixtures by pulsed corona discharge

“…NO conversion processes in plasma have been experimentally investigated by many researchers in terms of various operating parameters including reactor geometry (Mizuno et al, 1995;Wu et al, 2005), power supply (Matsumoto et al, 2010;Mok et al, 1998), polarity (Masuda and Nakao, 1990), gas composition (Arai et al, 2004;Sun and Yin, 2009), temperature (Eichwald et al, 2002) and additives (Cha et al, 2007;Lin et al, 2010). Kinetic models were also introduced to understand the mechanism of plasmainduced NOx conversion (Mok and Ham, 1997;Orlandini and Riedel, 2000).…”