NUMERICAL SIMULATION OF COMBUSTION PROCESS IN A 200MW TANGENTIALLY FIRED FURNACE TO STUDY FURNACE RECONSTRUCTION

Coal reburning is a new technique to reduce nitrogen oxides (NOx) emission. Numerical simulation of combustion process in a 200 MW tangentially fired furnace is performed on CFD (Computational Fluid Dynamics)software platform. Air staging technique is applied in reconstruction project 1 and coal reburning is applied in project 2. Results show that after furnace reconstruction, at 5.26m furnace height, temperature drops to a low lever and so does oxygen concentration but carbon monoxide concentration is the highest. Deoxidization zone is formed. Micronized coal reburning can reduce NOx emission up to 48.9%. Coal burnout ratio reduces after reconstruction that decreases furnace economy. Coal particle movements in furnace are random. Averagely, particles residence time is longer if they are injected from a higher height position.