摘要
采用提升管冷模实验装置,对40mm/20mm和24mm/12mm两种变径提升管和一种20mm单一直径提升管内的颗粒流动特性进行实验。考察了颗粒循环速率(Gs)和气速对变径提升管平均固含率(εs)和截面平均颗粒速度(Up)的影响。实验结果表明,采用变径提升管可改变固含率(εs)和Up分布;40mm/20mm变径提升管扩径段εs保持在0.1～0.3之间;提高Gs或降低气速,截面径向各点的εs都增大。提高Gs会导致Up增大。增大气速对扩径段Up的影响不明显,但会明显提高缩径段的Up。40mm/20mm提升管扩径段εs达到0.20以上,比24mm/12mm提升管扩径段的εs提高30%。相同气速和Gs下,40mm/20mm提升管扩径段底部的εs达到0.25,是20mm提升管的2～3倍。
In a fluidized bed with air-FCC catalyst circulating system solid flow patterns through two different changing-diameter risers 40 mm/20mm and 24 mm/12 mm and a simple 20 mm diameter riser were studied and compared. Effects of solid circulation rate and gas velocity on solid holdup and solid velocity distribution were investigated. Distributions of solid holdup and velocity were improved by changing-diameter risers. Solid holdup in 40 mm/20 mm changing-diameter riser is kept between 0.1 and 0.3. Higher solid circulation rate or lower gas velocity will bring forth higher solid holdup at different elevation heights. Solid velocity will increase accordingly to higher solid circulation rate. When gas velocity increases, the increase of solid velocity in expanding-diameter section is not obvious, while solid velocity rises clearly in shrinking-diameter section. Solid holdup in the 40 mm/ 20 mm riser is 0.20 and 30% higher than that in the 24 mm/12 mm riser. Solid holdup at bottom of expanding-diameter section of 40 mm/20 mm riser is 0.25 and 2 - 3 times of that in simple 20 mm diameter riser when gas velocity and solid circulating rate keep same.
出处
《石油化工》
CAS
CSCD
北大核心
2009年第1期40-45,共6页
Petrochemical Technology
基金
国家自然科学基金重大项目子课题资助(20490200)
关键词
催化裂解
低碳烯烃
提升管
变径结构
颗粒流动
catalytic pyrolysis
light olefins
riser
changing-diameter structure
solid flow
