【摘要】 从鞍钢九号高炉和首钢二号高炉风口前回旋区取出了经过部分燃烧的煤粉试样进行研究。结果表明:煤粉离开喷枪刚进入直吹管就开始了挥发份的挥发和燃烧反应;直吹管可能是煤粉预热和预燃烧的一个重要空间。但是煤粉在风口前回旋区仍不能完全燃烧尽,其半焦仍有20—30％是在回旋区外滴落带中焦炭层内气化的,但不影响高炉正常操作。为了进一步扩大喷煤量、节约冶金焦,必须增加能加快风口前煤粉燃烧速度的措施。试验室模拟高炉风口前燃烧条件的燃烧动力学试验表明:对于两厂所用的无烟煤,进一步磨细到小于目前60—80％为-200mesh的水平(亦不宜小于40μm左右),以及增加鼓风含氧到30—40％,进一步提高风温,改进煤粉在直吹管内的分布,在全部风口中同时均匀喷煤,选用烟煤代替目前的无烟煤是有效的。对喷吹前和部分燃烧后的煤粉试样进行煤岩相鉴定表明:烟煤燃烧不仅在表面而且在其内部同时剧烈进行,无烟煤粒的内部燃烧所占比重较表面燃烧要小,特别是首钢京西无烟煤。这和烟煤具有较好的燃烧性一致。根据传热和传质原理推导出一组煤粉燃烧的数字模型,将本文中两座高炉和试验室燃烧炉条件代入数字模型用计算机求解得到与实际近似的结果。更多还原

【Abstract】 The combustion efficiency study was made of the partially burnt Purverizeb coal, sampled from the raceway before the tuyere of blast furnace either No.9 of AISC or No.2 of SISC. Results showed that the injected coal started to volatilize and burn just it has entered the blowpipe where seems to be an important preheating and precombustion space before the raceway, however, it could not be completely burnt out there in front of tuyere. In order to replace more coke by injecting more coal, the laboratory simulation test on the combustion kinetics of the pulverized coal used by the above-mentioned two blast furnaces under conditions prior to tuyeres indicated technically possible by: pulverizing the coal down to 40 μm; enriching the blast with oxygen up to 30-40%; further raising the blast temperature; improving the injected coal distribution early in blowpipe; consistently injecting the coal at all tuyeres and selecting the variaty of coal of better combustibility, e.g., bituminous coal being superior to anthracite. Petrographic observation on coal samples prior to injection and after being partially burnt revealed that the bituminous coal burns violently and simultaneously not only on the surface but also in the interior of its particles, while the anthracite, especially, of SISC, mostly on the surface. Based on the theory of heat-transfer and mass-transfer, a set of mathematical model for combustion of pulverized coal has been derived. By substituting the combustion conditions of both above-mentioned two blast furnaces and laboratory test furnace into the model and with the aid of computer, a close approximation to the practice was obtained.更多还原