Research On Steam Blowing Synergistic Oxygen-enriched Flue Gas Circulation Technology For Sintering Quality Improvement And CO Reduction

In the process of China’s full industrialization,the iron and steel industry is still a pillar industry that plays an important role in supporting and promoting the process.In recent years,green and efficient sintering process was reversely compelling to be established by the rigorous environmental protecting policy and the concept of hill-silver hill instead of Green water and the Green Mountains.China has made important progress in achieving high-efficiency emission reduction of SO₂ and NO_x in the sintering process,most major steel companies have already met national ultra-low emission standards.To realize“Carbon peak”and“Carbon neutralization”,CO is gradually becoming the third generation pollutant of sintering flue gas,and its emission reduction technology has become a key common technical problem in the steel industry.To further promote the ultra-low emissions in the steel industry and face the important goal of ultra-clean emissions in the future,based on stabilizing the ultra-low emissions of SO₂ and NO_x,the triple coupling research of end treatment,process control,and emission reduction at source should be strengthened,to achieve high-efficient synergistic emission reduction of SO₂,NO_x,CO and other multi-pollutants in the sintering process.On the other hand,with the increase of steel production capacity and the large-scale development of sintering machines,it has become an inevitable trend to research and popularize the technology of improving sintering quality and saving energy.In this paper,the effect of steam injection and flue gas circulation on sinter quality and CO emission was studied,and new technology for improving sinter quality and reducing CO emission was developed based on steam injection and flue gas circulation,the processing system of sintering energy saving,quality improvement,and CO emission reduction has been established,which lays an important theoretical foundation for realizing low-cost production,high-quality development,and high-efficiency emission reduction in iron and steel enterprises.Based on the sintering process conditions and flue gas parameters of a steel enterprise,the Sintering Cup experiment was conducted by using the sintering raw materials at the sintering site and the steam injection technology on the material surface,the effects of total injection rate,injection flow rate and initial injection time on sinter quality index and CO emission reduction were studied.Under the condition of 50 kg sinter cup,the optimum experimental conditions of steam injection into the material surface should be as follows:8min after ignition,15 min after continuous injection,0.02 m³·min^-1 of injection flow,and180 g of total injection,the production rate,and drum strength were increased by 0.60%and 1.94%,the solid energy consumption was reduced by 1.15 kg·t^-1,and the CO emission was reduced by 10.91%.The results show that an appropriate steam injection on the sinter surface can reduce CO emission and improve sinter quality.The influence of different circulation modes of flue gas,such as inner circulation,outer circulation,and oxygen-enriched flue gas circulation,on the quality index and CO emission of sinter ore,was investigated by reforming the Sintering Cup device in the laboratory,compared with the reference standard,the vertical sintering speed and the utilization coefficient are lower,the solid energy consumption is slightly lower,and the other indexes do not change obviously,it can effectively solve the shortage of available oxygen in single flue gas circulation,and then solve the problem of reducing the sintering utilization coefficient.When the available oxygen content is increased to 15%and 18%respectively,the sintering production and Quality Index are superior to the standard,the CO emission reduction rates were 39.40%and 25.54%,respectively.The comprehensive effects of steam injection,flue gas circulation,steam injection combined with flue gas circulation on sintering quality improvement,and CO emission reduction were compared and analyzed,the optimal process conditions of CO emission reduction were selected,which provided the theoretical basis and data support for its industrial application.In this paper,we analyze the oxygen-enriched synergistic flue gas cycle matched with the industrial system of material surface blowing steam,identify the mechanism of enhancing the sintering process,improving the fuel combustion efficiency and reducing CO emissions under the synergistic conditions of the three,and propose the CO emission reduction process of sintering process based on the synergistic flue gas cycle of material surface blowing steam,finally realizing the triple benefits of energy-saving,quality improvement and emission reduction of sintering,and accelerating the transformation and upgrading of low-carbon and green steel industry.