预分解窑窑内通风量的优化

Optimization of air volume rate in PC kiln

对预分解窑窑内通风量的控制应把握好:在头煤用量波动范围内始终有足量的O_2供燃料燃烧,保证窑内不出现还原气氛,而且使窑内O_2适度偏大控制;窑尾缩口等部位的风速足以保证日常运行中不塌料,而分配给三次风管的通风量能满足炉煤燃烧对新鲜空气量的要求;烧成系统低能耗运行。三次风量在不同生产线存在差异很大,这种差异必然反映到窑内通风量上来,也说明这一领域需要继续研究。现阶段,预分解技术已经相当成熟,但二、三次风风量的比例优化问题明显落后。三次风闸板阀改筑缩口后,窑尾结皮大大减少,通风阻力不高、且相对稳定,窑尾排风的单位产量电耗下降;烧成带窑皮伸长3 m左右,总长接近20 m,且相当稳定;分解炉下锥塌料入窑的现象消失,窑头用煤量稳定。但所筑缩口不能调节风量。

Attention should be paid to air volume rate control trough the PC kiln in following three aspects:firstly,sufficient O_2 ought to be supplied for combustion in the fluctuation range of original coal consuming to ensure that no reducing atmosphere will be occur within the kiln,and even more O_2 can be properly controlled in the kiln;secondly,air velocity at the location of kiln inlet shrinkage etc.should ensure that no collapse will be occur in daily operation,and the air rate distributed to tertiary air duct can meet the requirement of coal combustion for fresh air in the precalciner;and thirdly, whole pyroprocessing system can be operated in low energy consumption status.Different production lines differ greatly in tertiary air volume rate,which will be inevitably reflected to air rate within the kiln.More research works should be done in this field.Nowadays,precalcining technique becomes fairly matured,but study on optimization for proportion rate between secondary air and tertiary air is still lag behind need. After the gate flap for tertiary air was replaced by making shrinkage,accretion in preheaters has reduced greatly,air resistance is not high but stable relatively,and power consumption for unit capacity for process air volume rate is also reduced;the coating length in clinkering zone will extend for about 3 meters with total length closed to 20 m,and the coating layer is fairly stable;the phenomenon of collapse material from precalciner down cone into kiln has been disappeared,and coal consumption at kiln outlet is also becoming stable.But of cause,the shrinkage can not regulate air volume rate at all.