No 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.

Coke oven gas (COG) injection is believed to improve the quality and yield of sinter in iron ore sintering process. A mathematical model is developed to simulate the sintering process with COG injection, particularly focusing on predicting the quality and yield of sinter. The model is validated by comparing the model predictions with sintering pot test data. Numerical simulations are carried out to investigate the influences of location, quantity and covering area of COG injection on the sintering process. The results show that the location of COG injection has a little influence on its effectiveness on sintering, with that the sinter yield decreases slightly with the delay of COG injection while the mean melt quantity index (MQI) and cooling rate (CR) hardly change. The quantity of COG injection has a great influence on sintering. With a typical COG injection area of 40% and injection location of 60 s after ignition, the sinter yield increases by 33.3%, the mean MQI increases by 9.5% and the mean CR decreases by 37.6% when COG injection is 0.5%. The injection area of COG has some interesting influence on its effectiveness on sintering. Under the condition of 0.5% COG injection from 60 s after ignition, with the increase of injection area, the sinter yield increases prominently first and then decrease significantly, attaining its maximum at 40% of injection area. At the same time, the mean MQI and CR attain their extrema also at 40% of injection area.

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/srin.202100823.