Thermal radiation characteristics in dilute phase region of the oxy-fuel combustion pressurized fluidized bed

Abstract

The thermal radiation transfer was complex due to high pressure, complicated flue gas components and abundant particles in the dilute phase region of oxy-fuel combustion pressurized fluidized bed. To carry out the radiation heat transfer, numerical simulations were done based on weighted sum of gray gases model (WSGG) and Mie theory. The Radiation Transfer Equations (RTE) of bubbling fluidized bed and circulating fluidized bed was solved by discrete ordinate method (DOM). The radiation heat transfer of fluidized bed under air combustion was verified and then the simulations were accomplished under pressurized oxy-fuel combustion hypothesis. The results revealed that the particle radiation was still dominant under pressurized oxy-fuel combustion. The change of total pressure and gas composition had slight effects on the radiation heat transfer in the fluidized bed. The gas radiation described by the new pressurized WSGG model and RTE solving by body-fitted coordinate system were much accurate to simulate radiation heat transfer. All the results were significant to provide theoretical basis of designing and building an oxy-fuel combustion pressurized fluidized bed.