喷吹城市生活垃圾对高炉冶炼过程的影响

Influence of municipal solid waste injection on blast furnace smelting process

中国城市生活垃圾产生量大,其蕴含的能量也十分可观,且城市生活垃圾中的其他垃圾主要成分为碳氢物质,热值较高,可用于钢铁行业部分工序使用,既能实现城市生活垃圾中碳氢组分的资源化利用,又能降低自身化石燃料消耗及对应的碳排放。基于物料平衡和热平衡计算,在高炉喷吹城市生活垃圾后对煤比、理论燃烧温度、煤气性质及高炉碳排放的影响进行分析讨论。研究结果表明,城市生活垃圾的分解热为1731.69 k J/kg,高于煤粉分解热;固定理论燃烧温度为2121℃时,城市生活垃圾代替煤粉喷吹的最大喷吹量为73 kg,固定鼓风氧体积分数为22%时,城市生活垃圾代替煤粉喷吹的最大喷吹量为83 kg;炉腹煤气量随城市生活垃圾喷吹量的增大而减小;炉腹煤气中H_(2)占比随城市生活垃圾喷吹量的增大而增大;40%城市生活垃圾粒化产物1∶1代替煤粉进行喷吹时,生产1 t生铁最多可降低碳排放169 kg。基于物质平衡和热平衡计算,城市生活垃圾代替煤粉进行高炉喷吹的最大值为83 kg,与国外高炉喷吹废塑料的喷吹量接近。喷吹城市生活垃圾后高炉理论燃烧温度保持在中国经验值范围内,炉腹煤气中还原气体占比增大、炉腹煤气指数降低、高炉利用系数提高、碳排放降低。研究结果可为高炉炼铁过程协同处置城市生活垃圾减污降碳技术的开发提供理论基础。

China's municipal solid waste is generated in large quantities,and the energy it contains is also very considerable.Other wastes in the municipal solid waste are mainly composed of hydrocarbons,which have a high calorific value and can be used in some of the processes in the iron and steel industry.It can achieve the resource utilization of the hydrocarbon component of municipal solid waste,while reducing its own fossil fuel consumption and corresponding carbon emissions.Based on the calculation of material balance and heat balance,the influence of blast furnace injection of municipal solid waste on coal ratio,raceway adiabatic flame temperature,gas properties and blast furnace carbon emission were analyzed and discussed.The results show that the decomposition heat of municipal solid waste is 1731.69 kJ/kg,which is higher than that of pulverized coal.At a fixed raceway adiabatic flame temperature of 2121℃,the maximum volume of municipal solid waste instead of pulverized coal injection is 73 kg,and at a fixed oxygen volume percent of 22%in the blast,the maximum volume of municipal solid waste instead of pulverized coal injection is 83 kg.The amount of bosh gas decrease with the increase of the amount of municipal solid waste injection.The proportion of H_(2) in the bosh gas increases with the increase of the amount of municipal solid waste injection.The production of 1 t pig iron can reduce carbon emissions by up to 169 kg when 40%of MSW pulverized products are inject 1:1 instead of pulverized coal.Based on the calculation of material balance and heat balance,the maximum volume of blast furnace injection of municipal solid waste instead of pulverized coal is 83 kg,which is close to the waste plastics injection rate of foreign blast furnaces.After the injection of municipal solid waste,the raceway adiabatic flame temperature of blast furnace remains within the range of empirical values in China,and the proportion of reducing gas in the bosh gas increases,the bosh gas index decreases,the utilization coefficient of the blast furnace increases,and the carbon emission decreases.The research results of can provide a theoretical basis for the development of pollution and carbon reduction technology by co-disposal of municipal solid waste in blast furnace ironmaking process.