Particle Conditioning for Improving Blockage Resistance of Denitration Catalysts in Sintering Flue Gas

Abstract

The stability and safety of selective catalytic reduction (SCR) systems are threatened by potential catalyst blockages caused by fly ash deposition. This paper proposes to improve the blockage resistance of denitration catalysts for sintered fly ash through particle conditioning. X-ray fluorescence spectroscopy, scanning electron microscopy, and laser particle analyzer were combined with laboratory heating experiments and field tests for systematic research. The results indicate that the composition and morphology of sintered fly ash are intrinsic factors contributing to catalyst blockage, while heating conditions act as external triggers. The sintered fly ash primarily exhibits a fluffy, branched cotton-like structure. Its main components are K2O, Fe2O3, Na2O, and CaO, with the alkali metal oxides of potassium and sodium comprising 20% to 50%. At ambient temperature, sintered fly ash presents no agglomeration, but significant agglomeration occurs as temperature increases. Particle conditioning effectively inhibits the agglomeration tendency of sintered fly ash. Field tests show that catalyst activity remains unaffected even under severe blockage conditions. The pressure drop across the catalyst layers increases progressively, with the first layer displaying the least pressure drop and the third displaying the most. After particle conditioning, the pressure drop across the catalyst is stabilized at values below 600 Pa, effectively mitigating the blockage issue in the denitrification catalyst for sintering flue gas. This research provides critical technical support for the stable ultra-low emission of NOx from sintering flue gas.