化肥生产中直转炉鼓风机突然断电的安全隐患分析及解决方法

在化肥生产中,直转炉鼓风机突然断电可能引起燃烧或爆炸,生产安全无法得到保障。采用变频器将后备直流电逆变成交流电,在突然断电时继续给鼓风机供电运行90 s,就可排尽炉内的可燃性气体,从而避免燃烧或爆炸事故的发生。改造后,不仅排除了安全隐患,而且鼓风机的节电效益远远超过了设备改造总投资,设备磨损和维护费用亦相应减少。

Influence of furnace temperature and non-uniform heat flux density on direct reduction process of newly designed carbon containing pellet

In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere pellets.In addition,furnace temperature and uneven heat flux density effects on the pellet direct reduction process were also studied.The results show that ellipsoid pellet is better than that of spherical pellet on metallization ratio.However,under the condition of non-uniform heat flow,the ellipsoid pellet final metallization rate and zinc removal rate were lower.Although the heat transfer effect of ellipsoid pellet with craters was not improved significantly,the metallization rate and zinc removal rate were found improved,which will have a cumulative effect on the pellets direct reduction process in rotary hearth furnace.Under varying furnace temperature conditions,the pellet temperature was higher than that of the constant furnace temperature.After 1200 s,pellet Fe concentration increased to 123.6%,metallization rate and zinc removal rate increased to 113.7%and 102.2%,respectively.These results can provide references for the carbon-containing pellet design used in rotary hearth furnace.

230 mm厚板坯表面纵裂成因分析及改进措施

某钢厂1台230 mm×1 410 mm双流板坯连铸机采用转炉直上工艺浇铸Q235B钢时,板坯出现表面纵裂纹。针对该钢厂的铸坯质量缺陷进行现场工艺追踪,对比和分析转炉工艺、钢水成分控制、结晶器水冷工艺、结晶器保护渣等关键工艺控制点,并采取了相关的针对性工艺改进措施,表面纵裂纹综合发生率成功从16.52%降低至1.25%、纵裂纹超深改判率从4.16%降低至0.18%。