Study On Performance And Operation Adaptability Of Gas Turbine SCR Denitration Catalyst Based On Vanadium And Tungsten System

Selective Catalytic Reduction?SCR?is the most feasible and mainstream technology for the ultra-low emission of nitrogen oxides from gas turbines wither in domestic or foreign.However,the catalysts used in domestic gas turbines are basically dependent on imports,and the related researches are still relatively rarely,which restrictsthe ultra-low emission process of nitrogen oxides for gas turbines in domestic.Therefore,it has important theoretical and practical significance to research and develop the denitration catalysts for gas turbines.This work uses a microcatalyst reaction evaluation device in combination with a variety of physicochemical systems such as BET specific surface area measurement,X-ray powder diffraction?XRD?,H₂-temperature programmed reduction?H₂-TPR?,scanning electron microscopy?SEM?,in-situ infrared?In-situ DRIFTS?,etc and deeply studied the relationship between the composition of V₂O₅-WO₃/TiO₂ catalysts of high vanadium system and the SCR properties,and discussed the promoter mechanism of WOx components.By simulating the operating conditions of gas turbine flue gas,we illustrate the adaptability of high vanadium system V₂O₅-WO₃/TiO₂ catalyst under the characteristics of gas turbine flue gas,and provide important reference information for the development of high efficiency gas turbine denitration catalyst.The main results are as follows:?1?.By systematically studying the relationship between the structure of high vanadium system V₂O₅-WO₃/TiO₂ catalysts with different tungsten loadings and its SCR properties,we found that WOx doping can significantly broaden the activity temperature range of the catalyst in the range of 280? to 440?.However,the maximum denitration performance of the catalyst at 380? cannot be further improved.?2?.The main reason for clarifying that WOx doping can broaden the active temperature range of the catalyst is that WOx and VOx species form a V-O-W structure on the surface of the catalyst and increase the proportion of V⁵⁺species,thereby increasing the surface Br?nsted acid and Lewis acid sites.In the SCR denitration reaction,the ability of the adsorption in acid sites and activate NH₃ on the surface of the catalyst is a reaction-fastening step,followed by reaction with the gas phase NO.?3?.When the V₂O₅ loading on the surface of TiO₂ is more than 3%,the doping WOx can still broaden the active temperature range,but the overall denitration efficiency of the catalyst decreases with the increase of V₂O₅ content.The main reason for the decrease of efficiency was found to be the formation of agglomerated VOx and WOx species on the catalyst surface.Therefore,in the SCR denitration reaction,the ability of adsorption and active NH₃ on the surface of the catalyst was weakened,resulting in a decrease in performance.?4?.Under the conditions of simulated gas turbine flue gas,the denitration performance of V₂O₅-WO₃/TiO₂ catalyst system with high vanadium is less affected by the change of oxygen concentration,and water vapor easily leads to reversible deactivation of the catalyst.The NO₂ gas component has a great influence on the performance of the catalyst.When the NO₂ content is less than 50%,the denitration efficiency increases with the increase of NO₂ concentration.However,when the NO₂content is greater than 50%,elevated NO₂ concentration will lead to a rapid decline in denitration efficiency of the catalyst.