Oxidative Decomposition of Adsorbed Toluene Using Ozone Concentrated by Nonthermal Plasma Flow

Abstract

Toluene decomposition is performed using an adsorbent and a nonthermal plasma (NTP) induced radical flow system that consists of a surface discharge and circulation flow. The liquid toluene is vaporized in the circulation channel connected to a blower and the surface discharge plasma reactor in series, and the toluene gas is adsorbed by the adsorbent. In order to accelerate the oxidative decomposition of the adsorbed toluene, two techniques are tested. In the first technique, concentrated ozone injection is utilized and the adsorbed toluene is decomposed using the NTP flow. This occurs after introducing the concentrated ozone in advance, through the bypass channel connected in parallel with the adsorbent. In the other technique, toluene decomposition occurs under the reduced pressure of the adsorbent chamber during the decomposition process, because accelerated toluene decomposition on the surface of the adsorbent is expected. This reduced pressure is in the range of −3 to −7 kPa and is achieved by regulating the ball valve located upstream of the adsorbent chamber. When the concentrated ozone is introduced into the circulation channel, the adsorbent temperature increases drastically and the conversion ratio of toluene to $\text{CO}_{x}$ (CO and CO2) increases by a factor of 2.0 in comparison with that without the concentrated ozone injection. In addition, the energy efficiency of the conversion increases by a factor of 1.9, even when the energy required for the concentrated ozone is included. However, there was no noticeable effect of the reduced pressure on the toluene decomposition under experimental conditions.