Study On Catalytic Combustion Of VOCs By Perovskite Supported On Monolithic Substrate

At present,the environmental problems caused by VOCs are common occurrence.As an effective control technology of VOCs,the key of catalytic combustion technology are that develope series of new catalysts,make the new type catalyst to effective loaded,scientific selection of carrier and play a catalytic activity or effective use the carrier of the positive cooperativity.To further improve the catalytic ability of active constituent is the focus of research in the present stage.In order to alleviate the VOCs pollution of the petrochemical enterprise,La_1-xSr_xMnO₃ was coated on cordierite honeycomb ceramics by equal volume impregnation method in this paper.The effect of preparation conditions and operating conditions of supported perovskite La_1-xSr_xMnO₃ catalyst on toluene catalytic combustion performance was investigated.The catalysts were characterized by XRD and BET as well.The results achieved are as follows.The honeycomb ceramics can be used as an excellent carrier for the active component of perovskite,and the perovskite LaMnO₃ can be improved by doping Sr to improve the activity of the perovskite type catalyst and reduce the ignition temperature.For the catalyst when the proportion of Sr doping is 0.2,the perovskite load is 20%,the calcination temperature of 700degrees in the catalytic efficiency of toluene,the catalyst of the ignition temperature of 247degrees and the complete combustion temperature of 309 degrees.Representations analysis shows that the catalyst has complete perovskite structure and proper amount of Sr doping can significantly improve the catalytic performance of the catalyst,the carrier and load group between closely.The active phase to uniform and minicrystal highly dispersed on the carrier and carrier,the catalyst than surface area has been further improved.The experiment results show that the pretreatment conditions of the carrier has great influence on the properties of the carrier.With different acid as pretreatment,the water absorption and specific surface area of the honeycomb ceramic carrier can be improved,and the pore volume and pore volume can be expanded,and the loading of the active component is improved,the catalytic efficiency is improved,and the service life is prolonged.Considering the pretreatment cost and weight loss rate,the best solution was selected as the best pretreatment method with 30%of the mass fraction of the nitric acid.It can be seen that the different forms of the carrier have the mesoporous structure,and the pore size distribution is reasonable.They are a suitable catalyst carrier.Investigation results of the impact of operating conditions on catalyst performance showed that that the conversion rate of toluene increased with the increase of reaction temperature.A lower space velocity was conductive to catalytic activity.With the increase of toluene concentration,the catalytic activity showed a decreasing trend after a slight increase at first.In a wider range of space velocity and concentration of substrate,monolithic catalysts have good catalytic performance.The catalyst maintained a high conversion rate of toluene with an increasing reaction time and showed high stability.