沙钢2500m^3高炉风口小套磨损的原因及对策

Causes Analysis and Solutions for Tuyere Small Sleeve Wear in Shasteel’s 2500m^3 Blast Furnace

沙钢2500m^3高炉二代炉役初期,部分风口小套内壁下部出现严重磨损,磨损处呈沟壑状;同时发现对应的煤枪出现了弯曲变形,煤枪出口向下偏离风口中心线。使用数值模拟方法,对比分析了煤枪出口与风口中心线重合、向下偏离两种工况下煤粉的运动。研究结果表明:煤枪出口偏离风口中心线时,煤枪出口处煤粉与风口内壁下部接触是导致风口磨损的主要原因。进一步研究煤枪弯曲变形的原因发现,该高炉经大修后,煤枪直径增大了1倍,但载气流量没有相应增加。采用数值模拟计算了不同载气流量下煤枪的冷却强度,发现载气流量偏小,煤枪冷却强度不足,从而导致了煤枪的弯曲变形。据此采取了增加煤枪载气流量的措施,煤枪变形和风口小套磨损得到了有效控制。

In the initial stage of the second campaign life of Shasteel’s 2 500 m^3 blast furnace, heavy wear was occurred in the lower part of the inner wall of some tuyere small sleeves, which appeared as ravine shape abrasion. It was analyzed that the abrasion was formed by coal particle friction. At the same time, it was found that the coal lance was deformed on abrasive tuyere, and that the outlet of coal lance was deviated from the center line of tuyere. By using numerical simulation method, the movement of pulverized coal under two working conditions, i.e., coincidence of the outlet of coal lance with the center line of tuyere or deviation downward, was compared and analyzed. Research results showed that when the outlet of coal lance deviated from the center line of tuyere, the contact between pulverized coal at the outlet of coal lance and the lower part of tuyere inner wall was the main cause of tuyere wear. From further study on the causes of coal lance deformation it was found out that after overhauling of the blast furnace, the diameter of the coal lance doubled, but the flow rate of carrier gas did not increase correspondingly. From the numerical calculation of cooling intensity of the coal lance under different carrier gas flow rates it was found that the carrier gas flow rate was relatively small, so the cooling intensity of the coal lance was insufficient, which led to the deformation of the coal lance. Accordingly, after adoption of the measures of increasing flow rate of carrier gas, the coal lance deformation and the tuyere small sleeve abrasion were effectively controlled.