Abstract:

In the process of degradation of toluene by plasma assisted catalysis, ozone is generated from reactive oxygen atoms along with the pollutants degradation. The changes of ozone concentration and degradation of toluene under different catalysts, discharge energy levels, catalytic section lengths and gas velocities were compared, and the formation of ozone in the process was explored. The results showed that the 7.5%Mn/cordierite catalyst placed in the discharge zone could inhibit the generation of ozone, promote the degradation of toluene, and improve the energy efficiency of the system effectively. The maximum concentration of ozone was reduced by 63.32mg/m³, compared with that without the catalyst. However, the catalytic performance of 0.2%Pd-0.3%Ce/cordierite on toluene degradation and ozone inhibition was poor. With the increase of the energy level of the system, the degradation rate of toluene and the ozone concentration increased gradually. The Ozone concentration was positively correlated with the length of catalytic section, but negatively correlated with gas velocity. Under different voltages, the ozone concentration firstly increased and then decreased. When the applied voltage was 13kV, the ozone concentration was the highest, but it decreased to zero when the voltage was raised up to 16kV.

Key words: non-thermal plasma, toluene, catalysis oxidation, ozone

摘要：

低温等离子体协同催化降解甲苯过程中，在降解污染物的同时活性氧原子聚合生成臭氧。本文研究比较了不同催化剂、放电能量水平、催化段长度和气速条件下的臭氧浓度变化和甲苯降解情况，探究了低温等离子体协同催化降解甲苯过程中臭氧的生成情况。研究表明，将7.5% Mn/堇青石催化剂置于放电区时能有效抑制臭氧生成，促进甲苯降解，提高系统能效，臭氧最高浓度相比无催化剂时降低63.32mg/m³；而0.2%Pd-0.3%Ce/堇青石催化剂对甲苯降解和抑制臭氧的性能较差。随着系统能量水平的提高，甲苯降解率和臭氧生成浓度逐渐升高。臭氧生成浓度与催化段长度呈正相关关系，与气速的关系则相反。在不同的外加电压条件下，臭氧生成浓度呈先上升后下降的趋势，当外加电压为13kV条件时臭氧浓度最高，当电压升高至16kV时臭氧浓度降为零。

关键词: 低温等离子体, 甲苯, 催化氧化, 臭氧