Experimental study on circulating fluidized bed with annular furnace and six cyclones

WANG Xiaofang; SHUAI Daping; LYU Qinggang; SUN Yunkai; WANG Fajun; SONG Guoliang

doi:10.13226/j.issn.1006-6772.2015.02.007

Abstract：In order to improve secondary air penetration and optimize heating surface disposition,a circulating fluidized bed( CFB)with annular furnace and six cyclones was proposed which was suitable for 600 MW or larger supercritical CFB boilers. The cold experiments were conducted to investigate gas-solid flow in the annular furnace and distribution of circulating rate among six cyclones. The results showed that the distribution of particles in annular furnace was similar to that in single loop CFB with conventional furnace. The concentra-tion of particle decreased along with the increase of furnace height and the distribution presented exponential type. The concentration of particle in the bottom of furnace decreased with the increase of superficial gas velocity,while the concentration of particle in the middle and top as well as outlet changed in the opposite trend. The circulating rate of each cyclone increased obviously. With the increase of static ma-terial layer height,the concentration of particles in the whole furnace rose,while the increase rate of concentration reduced in a higher height. When the superficial gas velocity was lower,the circulating rate didn’t vary with the increase of static material layer height. When the superficial gas velocity was higher,the circulating rate presented a slight increase with the rise of static material layer height. The distri-bution of circulating rates among six cyclones was almost uniform. The deviation of six circulating rates was 4. 5% under design condition. The inserted heat exchanger panels had little influence on the distribution of circulating rate.