烟气自循环在高炉制粉系统的应用

Application of Gas Circulation on Pulverizing System of Blast Furnace

在上海某钢铁厂COREX制粉系统的设计过程中,在理论分析和充分调研的基础上,对烟气自循环系统中各参数的选择及设备的选型进行分析。结果表明:COREX高炉制粉系统所用煤气的热值远高于普通高炉煤气的,在温度为80℃,磨煤机的出口温度不变的情况下,自循环烟气量比常规高炉制粉系统的少;系统配备了保安N2气系统,烟气中O2的体积分数大于12%,CO的体积分数大于0.03%时,自动充入N2,确保了系统的安全运行;与直排式工艺相比,自循环风可增加磨机的动力,有利于煤粉载出,烟气温度也得到利用,节约了能源,并且避免了外界因素对系统的干扰,系统运行更加稳定。

In the design process of the pulverizing system of COREX blast furnace in a certain iron and steel company in Shanghai, the choice of parameters and the type of equipment in the gas circulation were analyzed on the basis of theoretic calculation and enough investigation. The results show that the calorific value of gas in pulverizing system of COREX blast furnace is far higher than that of common blast furnace gas. In the cases that the temperature is 80 ℃ , and the outlet temperature of the coal pulverizer is invariant, the gas amount of circulation is less than that of the pulverized coal injection system of blast furnace. Security N2 gas system is equipped in the system. When the volume fraction of O2 in gas is larger than 12% and volume fraction of CO is larger than 0.03% , N2 gas is introduced automatically to ensure safe operation of the system. Comparing with the straight-line process, circulate wind can increase power of the mill, which is in favor of carrying out pulverized coal and utilizing gas temperature, The energy is saved and the interference of external factors on the system is avoided, so that the system runs more stable.