Suppressing the formation of NO_x and N₂O in CO₂/N₂ dielectric barrier discharge plasma by adding CH₄: scavenger chemistry at work

Abstract

Significantly suppressing the in situ NOx formation during plasma based conversion of low-cost impure CO2 feeds, by adding chemical scavengers.

Sustainable nitrogen fixation with nanosecond pulsed spark discharges: insights into free-radical-chain reactions

“…The FT-IR detected various gaseous products (i.e., NO 2 , NO, N 2 O, N 2 O 4 , HNO 3 ) after the NRP spark discharge. 21,42,53 Fig. 2(a) shows the presence of NO 2 vibrational bands at 1630 cm −1 and 2916 cm −1 , with relatively weak NO at 1900 cm −1 , N 2 O at 2250 cm −1 , N 2 O 4 at 1261 cm −1 , 1763 cm −1 , and 2976 cm −1 and HNO 3 at 1325 cm −1 and 1718 cm −1 .…”

“…During the discharge, the spark channels can be quickly formed and maintained for a long time, and the active species (i.e., electrons, vibrational-state molecules and free radicals) 29 and the gas temperature (T g , ∼3000 K) 21 in these discharge channels have been found suitable for nitrogen oxidation reactions (1) and (2). 41,42…”

The effect of H2O on the vibrational populations of CO2 in a CO2/H2O microwave plasma: a kinetic modelling investigation

“…The VT reactions between CO 2 vibrational levels and H 2 O ground-state molecules are listed in tables A1 and A2. Table A1 presents the rate coefficients calculated at 1500 K, while table A2 lists the coefficients (A, B, C) needed to calculate the rate coefficients at any other temperature, using equation (10) in the paper.…”

“…k (cm 3 s -1 mol -1 ) (1500 K) 12 CO 2 (02 0 0, 10 0 0) + H 2 O → CO 2 (01 1 0) + H 2 O 5.0x10 11 CO 2 (02 0 0, 10 0 0) + H 2 O → CO 2 (00 0 0) + H 2 O 6.2x10 10 CO 2 (03 1 0, 11 1 0) + H 2 O → CO 2 (02 0 0, 10 0 0) + H 2 O 1.5x10 13 CO 2 (03 1 0, 11 1 0) + H 2 O → CO 2 (01 1 0) + H 2 O 3.5x10 11 CO 2 (00 0 1) + H 2 O → CO 2 (02 0 0, 10 0 0) + H 2 O 1.3x10 12 CO 2 (00 0 1) + H 2 O → CO 2 (03 1 0, 11 1 0) + H 2 O 1.5x10 11 CO 2 (00 0 1) + H 2 O → CO 2 (01 1 0) + H 2 O 1.3x10 11 CO 2 (04 0 0, 12 0 0, 20 0 0) + H 2 O → CO 2 (00 0 1) + H 2 O 8.7x10 9 CO 2 (04 0 0, 12 0 0, 20 0 0) + H 2 O → CO 2 (03 1 0, 11 1 0) + H 2 O 2.3x10 13 CO 2 (04 0 0, 12 0 0, 20 0 0) + H 2 O → CO 2 (02 0 0, 10 0 0) + H 2 O 3.7x10 11 For the asymmetric mode levels, the following general reaction is used, for which the rate coefficients can be calculated for the higher levels at any gas temperature:…”

“…Therefore, different gas mixtures have already been studied. In CO 2 /N 2 mixtures, [8][9][10][11] N 2 shows beneficial effects due to the small energy difference between the first vibrational levels of N 2 and CO 2 , making a fast resonance transfer of vibrational energy possible [8,9]. If we want to explore the possibilities to create hydrocarbons, such as methanol, formaldehyde and formic acid, the addition of a hydrogen source would be necessary.…”