A NUMERICAL STUDY ON CHARACTERISTICS OF OXY- PULVERIZED COAL COMBUSTION IN A CORNER-FIRING BOILER OF 125 MWth SCALE

摘要

Characteristics of oxy-PC(Pulverized coal) combustion are one of the key parameters for design of a PC boiler. In this study, a conventional comer-firing boiler for a 125 MWth PC power plant was numerically simulated under the conditions of air-PC and oxy-PC combustion, using FLUENT 6.3. We used discrete phase model for simulating behavior of coal particles, and drying, pyrolysis, char combustion, char gasification and volatile combustion were considered for pulverized coal combustion. Parametric studies were performed for various design conditions of an oxy-PC corner-firing burner such as flue gas recirculation ratio, velocities, temperatures and oxygen concentrations of the primary/secondary oxidizer. Simulation results of oxy-PC combustion were also compared with conventional air-PC conditions, and optimum operating conditions under the view of combustion, NOx emission and radiative heat transfer were discussed.