CFD study of temperature distribution in full scale boiler adopting in-furnace coal blending

Numerical analysis of flow and combustion of Coal-Ammonia blend in coal-fired furnace

“…Combustion for the 10%, 20%, and 30% CR appeared to settle down only toward the upper elevations, where a semblance of a fireball started forming. Conversely, for the pure Adaro and 50% CR case, the temperature distribution became more uniform, and the once distinct fireball was no longer observed as the flue gases ascended to higher elevations [3]. Additionally, it was noted that the ignition of the coal-NH 3 blend occurred further away from the burners with an increase in the CR of NH 3 .…”

“…Conversely, only a minimal quantity of flue gases was detected in the pit hopper attributable to the characteristic tendency of cooler particles to descend due to their lower buoyancy. As the exhaust gases progressed from the furnace into the convective pass, their velocity experienced a decrement in magnitude, primarily ascribed to a substantial dissipation of kinetic energy from the flue gases to the furnace waterwalls, thereby decelerating the movement of the gases [3,19]. Flue gas velocity magnitude was observed to spike again as it progressed into the narrower convective pass attributable to the decrease in available cross-sectional area.…”

“…Only a minimal quantity of lower-temperature flue gases shifted to the pit hopper as cool particles tend to travel in a downward direction due to their lower buoyancy. As the exhaust gases travelled from the furnace windbox into the rear pass and outlet, their temperature decreased in line with the loss of thermal energy from the gases to the furnace waterwalls [3,19]. The flame became thinner and longer as the NH 3 CR increased, attributed to the heightened velocity of NH 3 jets from the burners [20].…”

“…The standard Reynolds Averaged Navier-Stokes equation is employed to solve the conservation equations for energy, mass, momentum, and gas species equations. Given the turbulent nature of the coal combustion process resulting from rapid changes in the furnace's pressure and velocity, the realizable k-ò method is chosen to close the turbulent model [3,14]. The transport equations for turbulent kinetic energy, k, and dissipation rate, ò are expressed in equations (1) and (2) respectively [15].…”

“…On a global scale, most coal power plants utilize pulverized coal for electricity generation due to its ability to enhance the economic capacity of the plant [3]. When a coal plant is initially commissioned, it is typically designed to combust a specific type of coal with defined characteristics, referred to as the plant's design coal.…”