Numerical Study and Hydrodynamic Calculation of the Feasibility of Retrofitting Tangentially Fired Boilers into Slag-Tap Boilers

Abstract

Retrofitting a tangentially fired boiler into a slag-tap boiler offers a solution for fully burning high-alkali coal in power plant boilers. Numerical simulation and hydrodynamic calculation of such a retrofit scheme were performed in this study. The maximum temperature in the furnace after retrofitting is 2306.8 K, surpassing the pre-retrofit temperature of 2095.8 K. The average temperature in the combustion chamber of the slag-tap boiler is 2080.3 K, which ensures that the slag can be discharged in a molten state. When the coal consumption is halved relative to the working condition of the boiler maximum continuous rating (BMCR) in the slag-tap boiler, the maximum temperature in the combustion chamber decreases from 2306.8 to 2220.3 K. However, the temperature distribution remains relatively uniform, ensuring that the slag discharge is not disrupted. In both of the working conditions calculated in this study, the fluid flow rates in the water-cold wall are positively correlated with the wall heat fluxes. The maximum wall temperatures under the two working conditions are 653.9 and 590.6 K, respectively, both of which are well within the safe limits for the wall material. The results illustrate the feasibility of the retrofit scheme.