Particle velocity in exit zone of combination of constraint riser in'zero-bed' operation mode

According to 'zero-bed' operation mode of combination of constraint riser reactor in commercial unit, in a largescale cold mode experiment device, we have studied the distribution of particle velocity in exit zone of riser in 'zero-bed'operation mode and the effects of superficial gas velocity, particle circulation strength and other conditions. The results were compared with the one of riser-bed coupled operation mode. Affected by the distributor, particle velocity has a decreasing trend and the length of the constraint effect decreases with the increase of the superficial gas velocity as the gassolid flow approaches to the exit of the riser. With the particle circulation strength increasing, the exit zone section particle velocity increases in core region and decreases in wall region. The amplitude of variation is greater than the other axial positions. With the superficial gas velocity increasing, the exit zone section local particle velocity increment is less than other axial positions under low gas velocity operation and is larger than other axial positions under high gas velocity operation. Compared with the riser-bed coupled operation, in the 'zero-bed' operation mode, the exit zone particle velocity is large in core region, but small in wall region. Radial distribution of particle velocity uniformity is poor.