烟气氧含量对循环烧结的影响研究

Effect of Oxygen Content in Flue Gas on Cyclic Sintering Process

为优化烟气循环烧结技术、实现节能减排,在实验室条件下,通过模拟烟气研究了循环烟气氧含量对烧结产质量指标、烟气成分排放规律、烟气温度、冶金性能和矿相组成的影响。结果表明:随着循环烟气氧含量增加,垂直烧结速度、成品率、生产率和转鼓强度都逐渐升高。循环烟气氧含量不低于18%时,氧含量变化对烧结过程燃烧率的影响有限,但循环烟气氧含量的减少会使烧结烟气中的氧含量降低,抑制烧结矿铁酸钙的生成,使还原度略有下降,低温还原粉化性能得到改善。与基准相比,采用循环烧结会延长料层高温维持时间并使循环烟气中的SO_2产生富集。将循环烟气氧含量控制在18%以上,可得到产质量指标良好、矿相组成合理的烧结矿。

For the purpose of optimizing cyclic sintering process and reaching the aim of energy-saving and emission reduction,effects of oxygen content in the circulated flue gas on the yield and quality indexes,emission rule of constituents in the flue gas, flue gas temperature, metallurgical properties, and mineralogical compositions were experimentally studied with simulated flue gas. Results show that with the increasing of oxygen content in circulated flue gas,the vertical sintering speed,yield,productivity and drum strength are all gradually increased. The oxygen content in circulated flue gas,if no less than 18%,has less impact on the combustion rate of sintering process. However,the falling oxygen content in the circulated flue gas will result in the oxygen content in sintering flue gas decreased and the generation of calcium ferrite inhibited. Consequently,the reduction of sinter will be decreased slightly and RDI is improved. Based on benchmarking,cyclic sintering process can prolong the time of sintering bed being at high temperature,and result in SO_2 enriched in the final sintering flue gas. It is concluded that keeping the oxygen content in the circulated flue gas above 18% can lead to the sintered product with favorable mineralogical compositions and good quality indexes.