Effects of Fuel Type and Operation Parameters on Combustion and NOx Emission of the Iron Ore Sintering Process

Abstract

A transient two-dimensional mathematical model is developed to study the influence of fuel type and operation parameters on combustion and NOx emission during the iron ore sintering process. The model was validated by comparing the model predictions with sintering pot test data. The predictions show reasonable agreement with the averaged values of the test data. In addition to the conventional sintering process, this model can also predict new processes such as flue gas recirculation, gas fuel injection, and fuel layered distribution. The simulation results show that the fuel NOx is the main part of the NOx emission during sintering, and thermal NOx forms a very little part. The produced NOx can be reduced not only by coke but also by CO around coke particles, with reduction proportions of 50% and 10%, respectively. Two types of coke A and B were compared. With Coke A as solid fuel and consumption of 3.8%, the NOx emission was 320 ppm. Increasing the replacement of Coke A with Coke B, the NOx emission was decreased, being decreased by 28.13% to 230 ppm with the replacement proportion of 50%. When only Coke B was used, the NOx emissions could be lowered by 53.13% to 150 ppm. Decreasing the particle size from 1.6 mm to 1.2 mm led the NOx emission to be increased by 10.93% from 320 ppm to 355 ppm. With Coke A as the only solid fuel, increasing the fuel ratio to 4.2% led the NOx emission to be increased by 9.38% to 350 ppm; increasing the oxygen content of inlet air from 21% to 30% led the NOx emission to be increased by 15.00% from 320 ppm to 368 ppm.