Preparation Of Cu-Mn-Ce-based Catalyst And Study On Characteristics Of Fluidized Catalytic Combustion Of VOCs

In recent years,many cities across the country are facing serious air quality problems,and the emission of VOCs is one of the important factors leading to increased air pollution.The use of catalysts for catalytic combustion in the fluidized state of the fuel has the advantages of large heat capacity,wide fuel adaptability,and so on,so it has certain technical advantages in the treatment of VOCs.However,the cheap catalysts for VOCs fluidized catalytic combustion need further study.The study on the kinetics of the fluidized catalytic reaction of VOCs and the influence of the combustion reaction is lacking.This article focuses on the above problems and plays an important role in promoting the governance of atmospheric pollutants.In this paper,a low concentration of benzene as the representative component of spray VOCs was used as the research object.Cu-Mn-Ce/?-Al₂O₃ catalysts were prepared by impregnation method.The influence of reaction conditions such as transition metal ratio,catalyst loading,reaction space velocity,and calcination temperature on the catalytic combustion characteristics of the catalyst was investigated.Combined with characterization methods,the microstructure and reactivity of the catalyst were analyzed.The effects of bed temperature,inlet air concentration,and fluidized wind speed on fluidized catalytic combustion of low-concentration benzene were studied.Based on the model analysis of low concentration benzene in the catalytic reaction in the fluidized state,the kinetic parameters and reaction control range of the fluidized catalytic reaction of the low concentration benzene were studied.The results show that the optimal molar ratio of Cu:Mn:Ce is 1:1.5:0.5,and the lowest activation energy is obtained.The addition of Mn ions can promote the low-temperature catalytic activity of the catalyst,while the addition of a small amount of Ce ions can increase the activity of the catalyst under high temperature conditions.The activity of the catalyst under complete oxidation reaction conditions is promoted due to the interaction between Cu,Mn and Ce,enhancing the thermal stability.The catalyst has the highest specific surface area when the calcination temperature is 600°C,and has the highest reactivity when the catalyst loading is 10%.The adsorbed water on the surface of the catalyst or the O-H bond of the hydroxyl group plays an important role in the catalytic process,especially the low-temperature catalytic process.When the low concentration benzene is catalytically combusted,the conversion rate of VOCs becomes larger with the increase of the bed temperature,and the VOCs in the fluidized bed move to the bottom of the bed under the catalytic reaction.Increasing the wind speed of fluidization reduces the conversion of reactants,and the catalytic reaction moves in the fluidized bed above the bed.When the inlet VOCs concentration is increased,the conversion of the reactants decreases,and the catalytic reaction in the fluidized bed moves above the bed.At temperatures below 250°C,the intrinsic kinetics affect the reaction.When the temperature is higher than 250°C,the low-concentration benzene reaction in the fluidized bed is influenced not only by the kinetics,but also affects the mass transfer between bubble phase and emulsification phase,as well as the adsorption and desorption of catalyst surface and gas,and the diffusion of reactants.