Em. Vanveldhuizen et al., ENERGY EFFICIENCY OF NO REMOVAL BY PULSED CORONA DISCHARGES, Plasma chemistry and plasma processing, 16(2), 1996, pp. 227-247
Pulsed positive corona discharges are used to remove NO from the flue
gas of a methane burner. At low power input this leads to an increase
in NO2, which shows that the process is oxidative. Removal efficiency
is greatest when discharges are produced with high-voltage guises, whi
ch are shorter in duration than the time required by the primary strea
mers to cross the discharge gap, in combination with a dc bias. Other
important parameters are input power density and residence time. Tire
best result obtained so far is an energy consumption of 20 eV per NO m
olecule removed, at 50% deNOx i.e., a removal of 150 ppm NOx, using a
residence time of 15 s and an input power density of 3.5 Wh/Nm(3). [Wh
/Nm(3) stands for watt-hour per normal cubic meter, i.e., at normal co
nditions (273 K and 1 bar). This implies that 1 Nm(3) contains 2.505 1
0(25) molecules.] There appears to be room for improvement by the addi
tion of gaseous and particulate chemicals or the use of multiple coron
a treatment. It is argued from comparison between results from models
and experiments that rite direct production of OH by the discharge is
only the initiation of the cleaning process.