Three-dimensional spray combustion simulation in a practical boiler

A three-dimensional computer model of a swirling fired-type furnace in which pulverized petroleum coke and ASTM No. 6 heavy oil are fed from two opposite side walls is presented. The predicted results are compared with measurements of exhaust NO concentration in an operating 125 MW (e) boiler with and without air introduced tangentially from the bottom of the furnace (below the lower burners) to convert H₂S to SO₂ effectively. Agreement between predicted and experimental data is quite satisfactory. Both show that the unburned ratio decreases with an increase in the fraction of the flow of tangential air to that of secondary air and with an increase of NO concentration. Our prediction also shows that when the tangential air is introduced from the bottom, a reduction in the H₂S formation rate is successfully effected in low-grade high-sulfur-content fuels such as heavy oil and petroleum coke.