氧气高炉回旋区内煤粉燃烧行为的数值模拟

Numerical simulation of pulverized coal combustion in the raceway of an oxygen blast furnace

  • 摘要: 炉顶煤气循环-氧气鼓风高炉炼铁新技术的工艺特点决定了煤粉在其回旋区内的燃烧条件与传统高炉相比将发生很大变化.本文建立了氧气高炉直吹管—风口—回旋区下部煤粉流动和燃烧的数学模型,研究了入口布置方式、氧含量、循环煤气温度以及H2O和CO2含量对煤粉燃烧的影响.模拟结果表明:三种引入方式中,假想的循环煤气和氧气混合进入方式明显优于循环煤气和氧气单独进入方式.当氧的体积分数由80%增加到90%,相应的煤粉燃尽率由87.525%提高到93.402%.循环煤气温度对煤粉燃尽率的影响并不显著.循环煤气中H2O和CO2的体积分数提高5%,风口轴线上气体的最高温度分别降低124 K和113 K.

     

    Abstract: The technological characteristics of a top gas recycling-oxygen blast furnace determine that in comparison with a traditional blast furnace the combustion condition of pulverized coal in the raceway has great changes. A mathematical model of pulverized coal flow and combustion in the blowpipe-tuyere-raceway bottom is developed in this paper. The influences of entry modes,oxygen enrichment,recycling gas temperature,H2O and CO2 contents on the burnout of pulverized coal are investigated by this model. The results indicate that an entry mode with the premixing of recycling gas and oxygen is obviously better than two other modes with recycling gas and oxygen entering alone. When the oxygen content changes from 80% to 90% the coal burnout increases from 87.525% to 93.402%. The effect of recycling gas temperature is not significant. The maximum gas temperature along the tuyere axis decreases by 124 K with the increasing of H2O content in the recycling gas by 5%,and it drops by 113 K for CO2.

     

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