DeNO/sub x/ process in flue gas combined with nonthermal plasma and catalyst

Catalysts were used to enhance NO/sub x/ removal reactions by the nonthermal plasma from room temperature to high temperature (500/spl deg/C). The NO/sub x/ removal rate was significantly affected by the type of the catalyst or the gas temperature. When the conventional three-way catalyst for automobiles was activated at 500/spl deg/C, nonthermal plasma was not effective in removing NO/sub x/. When hydrocarbons (ethylene) were added to the synthetic flue gas, zeolite catalyst became very active at high temperature, The combination effect of nonthermal plasma and catalyst was confirmed below 200/spl deg/C. More than 80% of NO/sub x/ was removed from synthetic flue gas by the combination of zeolite catalyst and hydrocarbons without nonthermal plasma discharge at 500 /spl deg/C. Nonthermal plasma treatment could be useful even at high temperatures, where catalytic reactions were dominant.