Large-eddy simulation (LES) is applied to a multi-burner pulverized coal combustion furnace in which three advanced low-NOx burners, each with a coal combustion capacity of approximately 100 kg/h, are vertically installed. The effects of an in-furnace blending method, in which different types of coal (high-fuel-ratio coal and low-fuel-ratio coal) are injected at each burner stage, on NO emission and unburned carbon fraction in fly ash are investigated. Pulverized Newlands coal and Tanito Harum coal that are classified as high-fuel-ratio coal and low-fuel-ratio coal, respectively, are used as fuels. The results indicate that oxygen is consumed rapidly and NO decreases near the burner from which the high-fuel-ratio coal is injected because the reducing atmosphere becomes dominant owing to the lack of oxygen. Further, the unburned carbon fraction decreases when low-fuel-ratio coal is injected from the upper burner because the residence time is longer for the combustion of high-fuel-ratio coal than when low-fuel-ratio coal is injected from the lower burner.
All Science Journal Classification (ASJC) codes
- General Chemical Engineering
- Mechanics of Materials