THE EFFECT OF JETTING GAS VELOCITY ON PARTICLE VELOCITIES IN A TWO-DIMENSIONAL JETTING FLUIDIZED BED UNDER PRESSURE

摘要

An optic fiber probe system was employed to investigate the profiles of vertical particle velocities in the outer regions close to the wall of a pressurized jetting fluidized bed.The influence of jetting gas velocity on the particle behavior has been systematically studied.A two-dimensional cold mode of a jetting fluidized bed coal gasifier, of 300 mm × 30 mm cross section was operated at pressures both 0.7 and 1.6 MPa and at high excess fluidizing gas velocity in the range of 0.20 to 0.40 m/s.The bed material was polystyrene with a mean particle diameter of 1.32 mm.The vertical local particle velocity (Vp) gradually accelerates with jetting gas velocity at high bed level.However, at low bed height level, Vp first increases and then is nearly constant at 0.7 MPa and gradually increases (maximum value about 0.63 m/s) at 1.6 MPa.