Performance Of Selective Catalytic Reduction Over Mn-Fe/USY Catalysts At Low Temperature

Selective catalytic reduction?SCR?is one of the main technology to eliminate NOx pollution,the point is to select the excellent performance of the catalyst,the relationship between denitration efficiency?operation cost and service life of the whole SCR system.This paper uses Mn and Fe as active components,using USY zeolite as catalyst carrier,the catalyst with different metal loadings prepared by impregnation method;The performance of resistance water and sulfur were studied,as well as the catalysts performance of NH₃-SCR affect by the amount of metal loaded.BET,XRD,SEM and FT-IR were used to characterize the phase structure and surface morphology of catalyst particles.Based on the reaction kinetics,the experimental data were regressed,and the kinetic parameters of SCR catalyst were studied.The kinetic model of Mn and Fe composite USY catalyst was established.The results show that:10Mn/USY,14Fe/USY and 7Mn-Fe/USY catalyst has better denitrification performance of catalyst,compared to Mn,Fe alone supported Mn-Fe/USY,catalyst supported both with Mn and Fe has better denitrification performance;in the input of H2O under the condition of each catalyst had a certain degree of reversible inactivation.The deactivation caused by SO2 was more serious than H2O,which is not reversible.At the same time,the influence of H2O and SO2 bonded on the irreversible deactivation of the catalyst was the most serious.The formation of white sulfate particles precipitated by the reaction of H2O and SO2.The specific surface area of catalyst decreased in different degree,and the pore size and pore volume decreased.14Fe/USY catalyst showed the best resistance to water and sulfur.The specific surface area of the catalyst decreases with the increase of Mn and Fe loading,but the metal loading has little effect on the pore size and pore volume.Under the same loading condition,the specific surface area of Mn/USY catalyst is bigger than Fe/USY.XRD characterization results show that with the increase of Mn and Fe loading,the characteristic diffraction peaks of USY molecular sieve are gradually weakened.In the FT-IR patterns observed in the USY molecular sieve was the characteristic absorption peak and absorption peak of Bronsted acid sites,the metal loading of active components to improve the catalytic activity of SCR at the same time,does not destroy the basic structure of molecular sieve.Kinetic results showed that the NO reaction order of the SCR reaction was 1,the NH₃ reaction order was grade 0,and the O2 reaction order was grade 0.5.The 7Mn-Fe/USY catalyst prepared by impregnation method has the lowest activation energy which is 17.56kJ/mol.Which means that compared with Mn/USY and Fe/USY,the Mn-Fe/USY catalyst can make the NH₃-SCR reaction easier.