新型悬浮预热器窑旋风筒的新设计

低压损旋风筒作为水泥生产过程中的一种节能方法,已经研制成功。按比例将各种普通旋风筒缩小加工成有机玻璃模型,并在相同条件下进行对比试验表明:压损的降低一般会使收尘效率降低。在经济上,收尘效率降低1％相当于9mm水柱压损,所以要求新旋风筒只降低压损而不降低收尘效率。考虑到旋风筒内部空气的流动情况,新型低压损旋风筒的设计思想应为: 1.为保证收尘效率不降低气体的圆周速度。 2.一般认为强制涡流是在涡流导向器下面的空间形成的,在此损耗大量能量,所以应减少流进这部分空间的气流量。 3.由于自由涡流是在涡流导向器外部形成的,能量损失小,而且减小的静压会转化成动压,所以这个区域的动压也应象静压一样有效回收。根据以上设想,我们制造出一种新的旋风筒模型,同时还改造了一个普通旋风筒,并分别进行了试验。试验结果表明;新型旋风筒性能良好,压损大约只有普通旋风筒的一半,而收尘效率并不降低。由于这种旋风筒涡流导向器下面装有导向叶片,只能用作顶部旋风筒,如作为其他旋风筒使用时,在更高温度下的使用帮助则有问题。因此我们计划研制另一种能在更高温度使用的新型旋风筒。

REDESIGN OF CYCLONES FOR NSP KILNS

As a measure to save energy in cement production processes, low pressure loss cyclones have been devel- oped. Scaled down perspex models of variors conventional cyclones were manufactured and compared to each other at the same condition. In general, reduction of pressure loss resulted in the decrease of dedusting effi- dency. As the reduction of dedusting efficiency by 1% is economically equivalent to the increase in pressure loss by 9 mmAq. it is necessary to reduce only its pressure loss without reducing dedusting efficiency. Consid- ering the air current in cyclones, the following three items were adopted as the desgn concepts for the new cy- clone. 1.To. maintain dust collecting efficiency, circumferential gas velocity should not be reduced. 2.As the forced swirl is thought to be formed in the room under the vortex finder, resulting a larger ener- gy loss, the air current into this part should be reduced. 3.As free swirl is thought to be formed at the outside of the vortex finder diameter, energy loss is small and the reduced static pressure is changed to dynamic pressure. In this part, the dynamic pressure should be efficiently recorered as static pressure. According to the above concept, a new cyclone model was manufactured and a commercial cyclone was modified, and both cold model cyclone tests and commercial cyclone tests were, performed. As the result of the above tests, this cyclone was confirmed as having excellent performance witht low pressure loss reduced to about half of the pressure loss of the conventional cyclone without reducing its dedusting efficiency. As this cyclone has guide vanes under the vortex finder, its durability in the higher temperature cyclones other than the top cyclone must be further investigated. We will try to develop another new cyclone which can be used at higher temperatures however it can be also recommended to USe a larger cyclone which needs somewhat higher initial investment, until the completion of our new cyclone.