Reticulated vitreous carbon electrodes for gas phase pulsed corona reactors

A new design for gas phase pulsed corona reactors incorporating reticulated vitreous carbon (RVC) electrodes is demonstrated to be effective at the re moval of nitrogen oxides from various gas mixtures containing O-2, N-2 wate r vapor, and ethylene, The reactor consists of either a plexiglass or glass cylindrical tube with macro-porous RVC electrodes placed perpendicularly t o the cylinder axis. Streamers propagate between the RVC disks providing a uniform exposure of the flowing gas stream to the electrical discharge, Thi s mode of operation provides for convenient reactor scale-up while maintain ing the interelectrode spacing in a moderate range, thus allowing scale-up without the need for higher voltage power supplies, It is further envisione d that the reactor can be operated with multiple sets of electrodes placed in series down the length of the reactor in order to facilitate high effici ency removal of air pollutants, Experiments with nitrogen oxide (NO) in dry air and lower concentration oxygen gas (i,e., 15% O-2, made from air and N -2) at room temperature and pressure show that the NO, as expected in an ox idizing environment, is converted to NO2. In addition, for these same dry g ases (100 ppm) and for these gases with higher inlet NO (180 ppm) upon the addition of water vapor total NOx is also removed. In dry gas at an energy density of 117 J/l 103 ppm, NO (100%) and 115 ppm NOx (96%) are removed at a cost of 3.9 g/kWh [257 eV/NO] (based on NO) and in humid gas at an energy density of 226 J/l 189 ppm NO (100%) and 219 ppm NOx (97%) are removed at a cost of 3.7 g/kWh (273 eV/NO) (based on NO), Measurements of water washin gs of the electrode surface indicate that for both the dry gas and humid ga s experiments significant quantities of nitrate are deposited on the surfac e of the electrodes.