摘要
根据空气 - FCC颗粒在 16 m高循环床提升管内的压力梯度实验数据 ,对提升管颗粒加速区的平均颗粒浓度、颗粒加速区长度以及操作条件的影响进行了系统的分析研究。颗粒的加速导致了颗粒表观浓度沿提升管轴向的不均匀分布 ,加速区截面上颗粒表观浓度随操作参数的变化明显不同于充分发展段 ;颗粒加速区长度受操作条件影响非常显著 ,增加颗粒循环量或减小表观气速 ,都将延长颗粒加速过程 ,颗粒表观浓度也随之增加 ;特别地 ,当提升管底部有大量颗粒聚集和絮状物形成时 ,颗粒加速区将显著增长 。
Systematic work was carried out to investigate the averaged solids holdup and the length of solids acceleration region in a riser, based on the experimental data of pressure gradients of air-FCC particles in a 16m high CFB riser. It was experimentally shown that solids acceleration results in the nonuniform axial distribution of solids holdups in the riser. In the acceleration region, the variation of apparent solids holdups with operation conditions was quite different from that in the fully developed region. The length of solids acceleration region was experimentally found strongly dependent on the operation conditions and varying the trends quite different form the reported in previous work. Increasing solids circulating rate and decreasing superficial gas velocity both lead to prolonged solids acceleration region and, therefore, higher solids holdups. Especially, with the accumulation of particles and the formation of particle clusters on the bottom of the riser, solids acceleration region could be e xtend rapidly, even taking up the whole height of the riser.
出处
《化学反应工程与工艺》
EI
CAS
CSCD
北大核心
2001年第2期101-106,共6页
Chemical Reaction Engineering and Technology
基金
国家自然科学基金-海外青年学者合作基金资助 !(No.2 992 80 0 5 )
