Study On The Degradation Of Ammonia-containing Waste Gas By Thermal Oxidation And Low Temperature Plasma

Ammonia-containing waste gas has become an important source of air pollution.The emission of ammonia-containing waste gas poses a great threat to our living environment and human health.Therefore,the treatment of ammonia-containing waste gas is of great significance to humans and the environment.In this paper,the ammonia-containing exhaust gas was degraded by thermal oxidation and dielectric barrier discharge plasma synergistic catalysis,and combined with quantum chemistry to simulate the decomposition reaction path of NH₃ and the effect of NH₃ on toluene degradation.In the thermal oxidation experiment,the effects of temperature,residence time,NH₃ concentration and O₂ concentration on the combustion characteristics of low concentration NH₃ were investigated by fixed bed reactor.The results show that the degradation rate of ammonia increases with the increase of temperature.The degradation rate of NH₃ increased significantly with the extension of residence time,but the amount of NO produced was also affected by the oxygen concentration.The initial concentration of oxygen has the greatest influence on the reaction,the oxygen concentration is too low,the ammonia gas degradation rate is low,the oxygen concentration is too high,the ammonia gas degradation rate is significantly increased,but too much NO is generated.When the initial concentration of ammonia is increased,the degradation rate of ammonia is also increased,and the selectivity of NO is lowered.The mechanism of thermal oxidation of ammonia was simplified and the kinetic parameters of combustion reaction of NH₃ in ceramic regenerator were calculated at 740～770 °C.Through the combustion experiment of ammonia gas in free space,it is proved that the combustion reaction of NH₃ in porous medium is surface reaction.Due to the high temperature required for the thermal oxidation of ammonia gas,in order to degrade ammonia at low temperature,an external electric field coupled catalysis method is adopted,that is,the dielectric barrier discharge is treated with Fe₂O₃@ZSM-5 and Fe0@ZSM-5 catalysts respectively.Ammonia.At the same time,the effect of oxygen-containing gas CO₂ in the ammonia-containing exhaust gas on the catalytic degradation of ammonia by dielectric barrier discharge was studied.Studies have shown that the dielectric barrier discharge can achieve complete degradation of ammonia at around 300 °C,which is 650 °C lower than the thermal oxidation of ammonia.The active component loading of the catalyst has a great influence on the degradation of ammonia gas,and the introduction of CO₂ effectively increases the degradation rate of ammonia gas.Using toluene as a VOCs simulant,the effect of dielectric barrier discharge on the degradation of toluene at different ammonia concentrations was investigated.The results show that ammonia gas can significantly promote the degradation of toluene in the dielectric barrier discharge.At the same time,the degradation path of ammonia gas is calculated by Gaussian quantum chemical software package and the promotion effect of ammonia on the degradation of toluene is verified.