Comparative modelling of NO_xand SO₂removal from pollutant gases using pulsed-corona and silent discharges

Abstract

A comparative modelling of pulsed-corona and silent discharges for removal of NO x , N y O x , SO 2 , CO and CH 2 O using operating equipment is presented. The main purpose is to compare, by modelling, the energy efficiency on removal of toxic impurities between two types of discharges at similar gas composition and temperature. Three different gas compositions: diesel engine exhaust, methane combustion products and pollutant air are considered. The simulation is based on an approximate mathematical model for plasma cleaning of a waste gas. The influence of non-uniform species distributions arising from a great number of streamer or microdischarge channels in a discharge chamber is taken into account. The modelling is carried out for a pulse series, considering after each discharge pulse the chemical and diffusion processes inside and outside the streamer trace. The distinctions of the cleaning processes in the pulsed-corona and barrier discharges are presented. It is also recommended when each of the examined discharges should be used.

Effect Of Propene, n-Decane, and Toluene Plasma Kinetics on NO Conversion in Homogeneous Oxygen-Rich Dry Mixtures at Ambient Temperature

“…It shows that, as for the N 2 /O 2 /NO mixture, the reaction of NO with O 3 dominates in the late afterglow. NO is produced by reaction (24), but also by (17) with same relative importance of about 45%. Two other minor reactions are (11) and:…”

“…Also for this mixture and contrary to propene, the importance of carbonated radicals is roughly constant as the number of current pulses increases. Another difference between the two mixtures is that NO production is dominated by NO 2 reduction, reaction (24), in case of ndecane whatever the discharge number is.…”

“…3) is predicted by the model. It results from a strong increase of NO gains though reaction (24) due to NO 2 production by reactions (20)- (22) during the first discharge and afterglow.…”

“…A lot of studies have been devoted to plasmas generated by dielectric barrier [11,12,15,18,[20][21][22][23][24][25][26][27][28][29][30][31] (DBD) or corona [13,14,16,17,19,24,[32][33][34][35][36][37][38][39][40][41][42] discharges, without a catalyst, in dry or wet oxygen-rich gas mixtures containing traces of NO, and with [12-19, 23, 27-31, 42] or without [11, 20-22, 24-26, 32-41] hydrocarbon additives. Such discharges are strongly non-homogeneous with many plasma micro-filaments following the propagation of streamers in the inter-electrode volume [43,44].…”

Removal of SO2 from Gas Streams by Oxidation using Plasma-Generated Hydroxyl Radicals

“…Filimonova [9] pointed out that a fractional active volume and the average electric field strength in dielectric barrier discharges (DBD) are 3-4 times and 100 times as high as that of corona discharge respectively. Chang [10,11], Dhali and Sardja [12] reported the method of combined plasma photolysis to remove SO 2 and NO from gas streams, in which gas-phase radicals were produced using DBDs and ultraviolet (UV) radiation, thereby allowing the simultaneous oxidation of SO 2 into H 2 SO 4 and NO into HNO 3 or N 2 .…”