摘要
基于烧结生产的复杂物理化学过程,建立了烧结床层传热、传质和流动的二维非稳态数学模型,考虑了孔隙率、物料颗粒当量直径等床层结构影响参数的变化,并对气固传热系数进行了修正。通过数值计算,获得了烧结床层的温度场、结构变化和烟气的流场、温度场、浓度场等。烟气出口温度、床层总压降与生产实测值吻合较好,验证了数学模型的正确性。进一步分析了燃料配比、风量和给料温度等操作参数对烧结过程的影响。研究结果表明:燃烧带的厚度、最高温度随着烧结过程的进行而逐渐增加。床层孔隙率、颗粒当量直径的变化主要发生在燃烧带的熔融、冷凝阶段。料层压损最大的是燃烧熔融层,其次是混合料带,最小的是烧结矿层。增加焦粉含量、提高烧结混合料的初温,有利于提高成矿质量;风量过大时,会造成成矿质量下降、生产成本提高。
Based on the physical and chemical processes in sintering,a two-dimensional unsteady state mathematical model describing heat and mass transfer and combustion is developed.It takes into account the effects of bed structural parameters,such as particle equivalent diameter and porosity,with gas/solid heat transfer coefficient modified.By numerical simulation,the evolution of bed structure,temperature field,gas flow and composition distribution is obtained.The temperature of outlet gas and pressure drop of bed are in good agreement with measured data,which validates the mathematical model.Effects of fuel ratio,inlet air velocity,initial material temperature and other operational parameters are further analyzed.It is shown that the thickness of combustion zone and the maximum temperature increases in the sintering process.Changes of bed porosity and particle diameter mainly occur during the melting and condensation stage in the combustion zone.The maximum pressure loss appears in the melting zone,followed by the raw material layer,and the smallest loss is in the sintered layer.Increasing coke content or/and temperature of the raw material helps to improve sinter quality.Excessive air velocity would cause low quality and extra costs.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2012年第5期1344-1353,共10页
CIESC Journal
基金
国家科技支撑计划项目(2008BAE67B01)~~
关键词
烧结床层
燃烧
传热传质
气固换热
数值模拟
sintering bed
combustion
heat and mass transfer
gas/solid heat transfer
numerical simulation
