天然矿物添加剂对高炉喷吹煤粉燃烧特性的影响

Effects of natural minerals on the combustion characteristics of pulverized coal

利用热分析法研究了大贵白云石、荣富镁石、东燃镁石、里领石灰石和方解石五种天然矿物添加剂对无烟煤燃烧过程的影响.考察了着火温度、最大燃烧速率、挥发分释放特性指数和燃尽特征指数等燃烧特征参数,求出了反应动力学参数活化能Ea和指前因子A.实验结果表明:大贵白云石、荣富镁石和东燃镁石能够显著促进煤粉的燃烧过程,降低着火温度,增大煤粉的挥发分释放特征指数D和煤粉的燃尽特性指数Cb,使最大燃烧速率前移至挥发分着火燃烧阶段;里领石灰石和方解石则相反.同时,动力学计算表明:大贵白云石、荣富镁石和东燃镁石使煤粉的活化能分别降低10.4%、14.5%和10.7%,对煤粉燃烧有助燃作用;里领石灰石和方解石使煤粉的活化能分别提高2.0%和4.3%,对煤粉燃烧没有助燃作用.

The effects of five natural-mineral additives on the combustion characteristics of anthracite were investigated with a synthetical thermal analyzer. The five natural-mineral additives are DG-dolomite, RF-humite, DR-humite, LL-limestone and calcite. Combustion characteristic parameters such as ignition temperature, maximum combustion rate, release property index and burn-out characteristic index were studied by thermo-gravimetric analysis, and the kinetics parameters of samples such as activation energy and frequency factor were also calculated. Experimental results show that DG-dolomite, RF-humite and DR-humite can promote the combustion of anthracite, decrease the ignition temperature, increase the release property index and burn-out characteristic index, and make the maximum rate of combustion move ahead the volatile matter combustion contemporaneously; nevertheless, LL-limestone and calcite have the opposite effect. Kinetics calculation results reveal that the addition of DG-dolomite, RF-humite and DR-humite decreases the activation energy by 10.4% , 14.5% and 10.7% respectively, and the decrease has a combustion-supporting effect in the combustion of blends. Adding LL-limestone and calcite increases the activation energy by 2.0% and 4.3% respectively, and the increase exhibits a fire-retardant effect in the combustion of blends.