OCR Text |
Show (5) Estimate of NOx generation by means of multiple regression analysis The results of the multiple regression analysis performed to estimate the volume of NOx generation with NUx control operation conditions as factors, were as follows: NOx = 56.0-31.73x[water spraying volume]***+0.00522xlCDF]*** +0.0195x[FDF in upstream of No.2 drying grate]*+0.00451 x[FDF in upstream of burning grate]**+0.000834 x[air volume for rotaly kiln]-454.9x[FDF air ratio to drying grate] F level; *** less than 1%, ** 1 - 5%, without asterisk, 10 - 20% The contribution factor of this function showed relatively high va I ue, i. e. 92.9%. 5) Conclusion In the case where NUx conlrol is carried oul by combuslion, the following items may be considered important: (1) (2) Generate as much reduction gas as possible in the drying zone. bJt(1 Ol~ 4t Let the reduction gas flAS? t peugh the after burning zone away from the main combustion zone, in which process utili ze the reduction gas for self-denitrification of a part of ~Ox. (3) Prevent unburnt gas from discharging, the shape of furnace should be made such that the exhaust gas can be mixed thoroughly in the after burning chamber. In consideration of the above points, NOx discharge can be controlled to lower than 100ppm by adopting the NOx control combustion method. 7 |