摘要
For the reduction of the operation cost,pulverised coal injection ( PCI) has become a standard practice in most steelworks worldwide.To aid improving the practical performance of blast furnace,coal combustion behaviours in the raceway of the blast furnace with different lance configurations and oxygen enrichment patterns were simulated in this research.Three lance configurations including single lance,double air- cooled coaxial lance and oxy-coal lance,in which the enriched oxygen flowed through the annulus of the lance as cooling gas,were examined.From the calculated temperature contours,early ignition is found when the double lance is operated due to better dispersion of coal particles in hot blast.Consequently,the coal combustion efficiency in the raceway could be improved.On the other hand,the ignition position for the oxy-coal lance injection is shifted away from the tuyere exit as a result of cooling effect by the enriched oxygen.As indicated by the calculated pressure drop within the combustion region,late ignition provides an advantage in lowering the pressure resistance across the raceway.Moreover,the coal combustion efficiency for the oxy-coal lance injection is not affected since the coal plume is surrounded by the enriched oxygen,which could intensify the combustion as long as the reactions are trigged in the raceway.