Numerical Study of the Effects of Burner Tilt and Coal Optimization on Combustion Characteristics of 350 MWe Tangentially Fired Pulverized Coal Boiler

Pelabuhan Ratu coal-fired power plant is a tangentially fired pulverized coal boiler type designed to use 4500–4700 kcal/kg HHV of coal. To optimize fuel costs, the coal specification was changed to 3500–4200 kcal/kg HHV. The decrease in coal quality consumed by the boiler is hereinafter referred to as coal optimization. The coal calorific value used in this coal optimization is 4080 kcal/kg HHV. However, even though it looks economically profitable, coal optimization will certainly have impacts on the operation and maintenance of the boiler. One of the combustion facilities that can be optimized during this coal optimization is the burner tilting. The study was carried out numerically using computational fluid dynamics (CFD) by varying the burner tilt angle −30°, −20°, −10°, 0°, and +5°. The amount of coal and combustion air for each variation of the burner tilt angle is the same. The most optimum tilting angle when coal optimization is −30° with consideration of (1) the lowest FEGT, which is 1237.01 °C, (2) the lowest average temperature deviation between the simulation results with design coal and worst coal in the convection area is 36.12 °C and 27.26 °C, respectively, (3) the least O₂ content at the boiler outletis 3.27%, and (4) the highest CO₂ content at the boiler outlet is 17.60%. However, burner tilting as much as −30° is not applicable, because the range of burner tilt angle is only ±20°, so that the most optimum tilting angle that can be applied in the actual condition is −20°.