摘要
5在矩形移动床内考察了颗粒下移速度、颗粒堆积状态及空腔生成和长大发展过程等因素对压降的影响.在错流气体速度为0.09～1.35m/s、颗粒下移速度为0.95～9.68cm/min的较大变化范围内进行了实验研究.结果表明,颗粒下移速度对压降几乎没有影响;当错流气速足够大时移动床内将出现“空腔”和“贴壁”等现象,空腔的发展过程造成压降随时间出现稳定、微波脉动和大幅波动3种变化;欧根公式适用于低错流气速时的移动床压降;高错流气速下空腔出现了“生成-长大-塌落-流化”的循环变化过程.在实验基础上建立了有空腔时的移动床压降模型,并对空腔尺寸进行了无因次关联,其床层压降的计算结果与实验值相符.
The pressure drop of gas flowing through the cross-flow moving-bed was investigated in a two-dimension rectangular apparatus. The effects of particles flow rate, superficial gas velocity, formation and development of cavity/raceway and voidage of particles on the pressure drop were investigated experimentally with the operation conditions of 0-1.35 m/s of superficial gas velocity and 0.95-9.68 cm/min of particle velocity. The experimental results show that the particle velocity has little influence on the pressure drop; the phenomena of cavity and pinning occur when the cross-flow velocity is high enough, The development of a cavity or a raceway can cause three types of pressure drop with time, which are stabilization, slight fluctuation and severe fluctuation. The pressure drop of moving-bed can be calculated by Ergun＇s equation at low velocity of cross-flow gas. Cavity appears in a process cycle of ＂formation-growing up-coUapsing-fluidization＂ at high gas velocity. On the basis of experimental results, a model for calculating the pressure drop when a cavity occurs and a dimensionless relationship of cavity size is conduced, which agree with the experimental data.
出处
《过程工程学报》
CAS
CSCD
北大核心
2006年第5期697-702,共6页
The Chinese Journal of Process Engineering
关键词
错流移动床
空腔
压降
cross-flow moving bed
cavity
pressure drop
