Research and application of low NOx control technology for vertical annealing furnace
The correlation between the NOx emission concentration and the strip gauge and the heat load in the heating section was analyzed by data analysis method.The results show that when the heat load is less than 41％,the NOx emission is less than 150 mg/m3.With the further increase of heat load output,the NOx emission showed a linear increase.In order to reduce the NOx e-mission concentration under high heat load,low NOx control research based on the formation mechanisms of NOx was carried out.First of all,the relationship between the residual oxygen in the flue gas of the burner with different rated power and the a-mount of NOx production was determined through the test,and the control range of residual oxygen in the flue gas of the burner was determined to be 2.5％-4.4％.Through further quantitative analysis of the impact of residual oxygen on burner power,it was found that not only NOx generation decreased with the residual oxygen,but also the heating capacity of the annealing furnace was im-proved.When the residual oxygen content decreased from 6.0％to 3.5％,the NOx generation of 80.0,120.0 and 160.0 kW burners decreased by 41.53,28.51 and 26.96 mg/m3,respectively,while the burner power increased by 14.7,22.3 and 29.3 kW,respectively.Secondly,the relationship between residual oxygen,combustion air pressure difference,and flue gas tempera-ture was studied,and the"Z"method of adjusting the residual oxygen in the flue gas of the burner was formulated,which effectively solved the problem of the residual oxygen in the flue gas of the burner exceeded the control upper limit.Finally,the influence of different diameter of bell mouth from heat exchanger on NOx generation and annealing furnace heating capacity was studied.The results show that reducing the diameter of bell mouth from φ29.5 mm to φ27.5 mm can reduce the NOx generation by 44.78％without affecting the heating capacity of annealing furnace.With the application of low nitrogen control technology,the average NOx emission con-centration decreased from 149.22 mg/m3 to 111.57 mg/m3.
万方数据
维普
