Numerical modeling of a bubbling fluidized bed coal gasifier by kinetic theory of rough spheres

Flow behavior and coal gasification are simulated using the kinetic theory of rough spheres with the coal reaction models in a steam-assisted bubbling fluidized bed coal gasifier. The collisions of inelastic rough spheres are modeled based on the kinetic theory of rough spheres with gas-solid interactions. The fluctuation kinetic energy of particles is introduced to characterize the random motion of particles as a measure of the translational and rotational velocities fluctuations. The coal gasification models compose of devolatilization model, char gasification model and gas phase reaction model. Simulations are carried out in a steam-assisted fluidized bed coal gasifier with a height of 2.0 m and a diameter of 0.22 m. The gasification performance has been predicted, and the distributions of concentrations, velocities, temperatures of gas and solids phases and gas compositions are analyzed in a 2D model of a steam-assisted bubbling fluidized bed coal gasifier. Predicted gas species concentrations are in agreement with experiments.