关键词: 铁矿烧结, 喷洒蒸气, 气相体系, CO氧化

Abstract: The iron and steel industry, as one of the lifebloods of the national economy, has become a key focus of attention in the field of energy conservation and emission reduction as the goals of carbon peaking and carbon neutrality continue to advance. Iron ore sintering is the second largest carbon emission process in the iron and steel industry after blast furnace ironmaking. Existing studies indicate that steam injection onto the sintering bed surface can improve the fuel combustion efficiency of the sinter layer, increase the sintering index, and reduce CO emission concentration of flue gas. In this work, the mechanism of CO emission reduction by injection of steam onto the sintering bed surface was studied. The effect of steam on CO gas oxidation at high temperatures was studied by using a fixed bed experiment to simulate the injection steam onto the sintering bed surface. The results showed that the steam in the gas phase system can significantly promote the oxidation of CO. The gas phase oxidation of CO almost did not occur in the condition of no water vapor, and the steam promoted CO oxidation significantly when the volume fraction was above 2.0%. The CO oxidation reaction catalyzed by steam starts at 650℃, and the reaction accelerates with the increase of temperature. A stable and continuous reaction interval appears at 700℃ and above. With the volume fraction of steam increasing, the beginning time of CO gas phase oxidation was advanced and the duration was extended. Under the conditions of O2 and CO volume fractions of 2.0% and 2.5%, respectively, the steam volume fraction of 12.0% can promote the highest CO oxidation efficiency, and the CO oxidation efficiency can reach at 99.95%. The research was of great significance for improving the theory of steam injection technology on sinter surfaces and guiding production practice.

Key words: iron ore sintering, steam injection, gas phase system, CO oxidation