Preparation Of Vanadium-Based Catalytic Ceramic Filters And Their Denitration Properties

At present,flue gas denitrification is widely used in large-scale boiler flue gas such as thermal power plants in China,and the technology is relatively mature.However,there are problems such as poor low-temperature activity,large amount of heavy metals,and secondary pollution of catalysts.Therefore,an integrated catalytic filter element with high activity for low-temperature denitration and less catalyst consumption has been developed and applied in industry.The catalytic filter element also has the function of dust removal and denitration of flue gas.The pores of the substrate are abundant,and the microscopic pore structure of the surface can be dense.More than 99%of the smoke dust is retained;the catalyst slurry is applied to the internal support of the filter element,dried and calcined,and the simultaneous denitrification function can be realized when the gas passes through the filter element.This article mainly focuses on improving the activity of catalytic filter and conducting it for pilot testing.This article first investigated the effects of three typical ceramic filter substrates on catalyst dispersion and denitrification activity.Three typical commercial ceramic filter elements were used to coat V2O5-WOO-MoO3/TiO2 denitration catalyst slurry.The program was heated,dried and calcined to produce the integrated material.The dedusting integrated catalytic filter material was subsequently examined under the same conditions to investigate the influence of the chemical composition and pore size structure of the ceramic filter element on the denitrification performance of NH3-SCR.XRD,XRF,SEM,mercury intrusion,and other analysis results show that the fibrous structure of the ceramic filter element with low alkali metal and alkaline earth metal elements and uniform pore size distribution promotes catalyst dispersion,improves the denitrification activity of the integrated filter element,and reduces gas pressure drop.The NO conversion can be above 90%in the temperature range of 220-380 ?(face velocity = 1 Nm/min,NH3/NO = 1(?)),and the NO conversion can still maintain above 90%after introduction of 15%(?)H2O and 600 ppm SO2 in the temperature range of 260-450 ?.The excellent DeNOx performance of the catalytic filter meets well the demands of practical industrial application.At the same time,the activity of denitration of vanadium-based catalytic filter element in the high temperature range(350-500?)decreases rapidly.The higher the vanadium content is,the more serious the activity declines.This restricts the application of the catalytic filter element under high-temperature flue gas conditions.Therefore,XRD,SEM,NH3-TPD,and in situ infrared spectroscopy were used to investigate the dispersion and agglomeration of different vanadium catalysts and their effects on denitrification in high temperature zones.The results showed that:with the increase of vanadium oxide content,The agglomeration of catalyst particles is more serious and the active number of catalysts is on the rise.The number of active sites at low temperature(T<330?)determines the catalytic activity,and at high temperatures(T>330?)the catalyst follows the ER mechanism,and the ammoxidation is the dominant temperature.active.In summary,although high vanadium content catalysts have more active sites,their more severe particle agglomeration and strong ammonia adsorption at high temperatures have led to an increase in their ammonia oxidation capacity,which has reduced catalyst selectivity and denitrification.effectiveness.The integrated catalytic filter prepared in the laboratory was applied to a glass furnace pilot test,and the dust removal effect was found to be very good.The catalytic filter operation for 2 months revealed that the denitrification rate was stable at more than 90%,fully meeting the requirements of industrial applications.