Numerical simulation on gas-solid flow during circulating fluidized roasting of bauxite by a computational particle fluid dynamics method

Abstract

A full-cycle numerical simulation of a circulating fluidized bed (CFB) by the use of the computational particle fluid dynamics (CPFD) method has been developed. The effects of the presence or absence of the secondary air, different secondary air positions, and different secondary air ratios on the gas–solid flow characteristics were explored. The results show that the presence of the secondary air makes a core-annular structure of the velocity distribution of particles in the fluidized bed, which enhances the uniformity of particles’ distribution and the stability of fluidization. The position and the ratio of the secondary air have a significant impact on the particle distribution, particle flow rate, and gas flow rate in the fluidized bed. When the secondary air position and ratio are optimal, the particles, particle flow rate, and air flow rate in the CFB are evenly distributed, the gas–solid flow state is good, and the CFB can operate stably.