Preparation Of Zeolite Supported Catalyst By High Gravity Technology And Catalytic Combustion VOCs

Volatile organic compounds?VOCs?,as the main source of air pollution,have attracted worldwide attention.The common methods to eliminate VOCs are adsorption,absorption,condensation,catalytic combustion,membrane separation,etc.Because of the advantages of catalytic combustion,such as high efficiency,low energy consumption and no secondary pollution,it is considered to be an effective method to eliminate VOCs.Therefore,the preparation of catalytic combustion catalyst has attracted more attention.The key of catalytic combustion lies in the catalytic activity of catalyst,which is not only related to the components of catalytic activity,but also affected by the preparation method and technology of catalyst.High gravity technology can be used in liquid-solid adsorption process to enhance the mass transfer between the active component and the carrier and make the solution of the active component disperse evenly.Considering the influence of the preparation method and the adsorption process between the carrier and the active component,based on the advantages of high gravity technology,CuMn/ZSM-5-Higee catalyst was prepared by using high gravity technology,and the catalytic activity of the catalysts prepared by different methods was investigated by comparing CuMn/ZSM-5-Traditional impregnation method.The results showed that CuMn/ZSM-5-Higee had better catalytic activity than CuMn/ZSM-5-Traditional,and the conversion rate of toluene reached 98%at 270?.The supported catalyst prepared by high gravity technology has higher loading capacity,better dispersion and better low temperature catalytic activity.With the increase of rotating packed bed speed,the loading capacity of active components gradually increased.With the increase of flow of active components,the loading capacity of active components first increased and then decreased.This is due to the enhanced mass transfer between the active component and ZSM-5 under the heavy field,which greatly improves the dispersion and loading capacity of the active component on the carrier and improves the utilization rate of the hole structure of ZSM-5.In order to further develop and prepare catalysts with high catalytic activity,CuMnCe/ZSM-5-Higee ternary composite oxide catalyst was prepared by high gravity technology according to the principle of economic benefit and low temperature catalytic oxidation,and the catalytic activity of ternary metal oxide catalyst was investigated.The results showed that CuMnCe/ZSM-5-Higee had better catalytic activity than CuMn/ZSM-5-Higee.The conversion rate of toluene reached 98%at 250?.Experiments by BET,XRD,SEM,XPS,H₂-TPR,such as the catalysts were characterized,the results show that the CuMnCe/ZSM-5-Higee formed cerium base solid solution and the activity of Cu oxides,Mn oxides,cerium base solid solution has a very rich oxygen defects,is the catalyst for oxygen supply center,Cu oxides and Mn oxides is active phase catalytic oxidation of center,thus promote the catalytic oxidation process,is advantageous to the low temperature catalytic oxidation of toluene.In this paper,CuMn/ZSM-5-Higee catalyst was used to investigate the influence of toluene concentration and oxygen content on the catalytic toluene reaction process.The results show that:when the toluene concentration is too high,the catalytic efficiency of the catalyst decreases;with the increase of oxygen content,the conversion of CuMn/ZSM-5-Higee catalyst to toluene increases,when the oxygen content reaches a certain value,the conversion of toluene tends to be stable;catalytic The catalytic activity of the catalyst decreased with the increase of space velocity,while the catalytic activity of CuMn/ZSM-5-Higee only decreased slightly,which indicated that the space velocity range of CuMn/ZSM-5-Higee prepared by high gravity technology was wide.In this paper,we study systematically the catalytic activity of catalysts prepared by high gravity technology and the catalytic activity of ternary composite oxide catalysts and their properties and structural parameters were analyzed.And the influencing factors of catalytic combustion of toluene were also discussed.This research provides technical support for the industrialization of VOCs elimination technology.