Fluidization Characterization of Coal Powder in a Novel Fluidized Bed with the Inner Cyclone

A novel fluidized bed with the inner cyclone was developed to realize pulverized coal self-sustained preheating in this study. The temperature of the coal can be heated up to 850 ^oC-950 ^oC by the coal partial combustion in the novel inner fluidized bed combustor (IFBC). The hot pulverized coal is fed into the furnace of pulverized coal (PC) boiler. The integrated PC boiler combined IFBC will lead to the easer ignition and reduce the NOx emission for the low-rank coal. In order to investigate the operating performance and gas-solid flow characteristics in the IFBC , the cold experiments were carried out in a small-scale IFBC installation of 0.15m in diameter and 1m in height, continuous feeding using Geldart Group A particles. The influences of the superficial gas velocity on the pressure profile and particle balance were studied. The experimental results showed that the IFBC can be operated stably, and the hot coal output rate is steady when the superficial gas velocity is in the range of 1.5-2.25m/s, while the hot coal output is nearly equal to the cold coal input in the condition of continuous feeding. Based on the cold test, the hot inner fluidized bed combustor was designed which thermal input is 2MW. The hot experimental results showed that the temperatures along the riser are distributed uniformly that verifies the good fluidization in the IFBC.