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在全面掌握烧结烟气特性的基础上,建立烟气循环系统风氧平衡模型,分析烧结废气中O2体积分数、富氧气体中O2体积分数及漏风率等因素对烧结废气循环率的影响规律,提出了适宜的内外循环方案.研究结果表明:烧结机前段风箱废气中O2体积分数较低,为10%~13%,在18号风箱之后O2体积分数逐步上升.烧结废气温度升高,气体密度变小,流速增大,但各风箱支管内废气标况流量波动幅度不大.烧结循环废气和富氧气体中O2体积分数越高、烧结机漏风率越低,则烟气循环率越高.以环冷机热风为富氧气体,烟气内外循环率可达30%;以工业纯氧为富氧气体,烟气内循环率达40.70%;烟气外循环率达59.93%.内循环工艺在风箱支管取风,操作灵活,需外配大功率变频抽风机,工程改动量多,固定投资高,更适于新建项目;外循环工艺在主抽风机后烟道取风,无法避免烟气一次循环后的再生效应对烧结生产的影响,只需外配小功率引风机即可,更适用于改造项目.

Based on comprehensive understanding of the features of sintering flue gas,the wind-oxygen balance model of flue gas circulation was developed. By analyzing the simulation results,how the recycled sintering flue gas oxygen con-tent,oxy-enriched gas oxygen content,and leak rate of sintering machine influenced the circulation rate of flue gas of sin-tering were studied,and then the reasonable schemes for inner and outer gas circulation were suggested. The results show that,at the first several wind boxes,the oxygen volume content of sintering flue gas was low(10%-13%),and after the No. 18 wind box,the oxygen content grew gradually. The gas temperature of gas became higher,the gas density reduced and the flow speed became high,while the variation of gas flow capacity under standard condition was not distinct for ev-ery branch pipe of wind box. The higher the oxygen content of recycled sintering flue gas and oxygen-enriched gas,and the lower the leakage rate of sintering machine,the higher the circulation rate of sintering flue gas. Taking the hot wind in circular cooler as the oxygen-enriched gas,the inner and outer circulation rate of sintering flue gas could reach to 30%. Taking the industrial pure oxygen as the oxygen-enriched gas,the inner circulation rate could 40.70%,and the outer circu-lation rate would be 59.93%. Inner circulation process needs to take wind at the branch pipe of wind box,which is easy, but large power frequency conversion fan should be equipped. Hence,lots of changes should be made and the fixed invest-ment is high. So,the inner circulation process is proper for new project. Meanwhile outer circulation process takes wind at the flue behind main drawing fan,so rebirth effect on sintering process after flue gas once cycle cannot be avoided. Outer circulation process is more suitable for renovation project,because low-power induced draft fan is enough.