高长径比三相内环流反应器中相含率的分布研究

Studies on distribution of phase holdup in three-phase internal-loop airlift reactor with big ratio of height to diameter

在长径比为22的三相内环流反应器中,常温常压下,以空气-水-石英砂为物系,根据无因次准数建立了气含率、固含率的预测模型,考察了在不同粒径下上升区气含率、下降区气含率和上升区固含率、下降区固含率随表观气速的变化规律和不同固体体积分数下轴向固含率的分布情况。结果表明:不同粒径下上升区和下降区气含率均随表观气速的增大而增大;当粒径(ds)≤0.3mm时,上升区固含率随表观气速的增加呈平缓趋势,下降区固含率随表观气速的增加而增加,当0.3mm<ds≤1.2mm时,上升区固含率随表观气速的增加而呈先下降后增加的趋势,下降区固含率随表观气速的增加而下降;不同固体体积分数下的固体颗粒的固含率随着轴向高度的增大而变化平缓,能够均匀的分布在反应器中;气含率和固含率的计算值和实验值吻合较好,其平均相对误差分别为6.32%、4.56%。

Based on the dimensionless numeral to establish gas holdup and solid holdup model of the air-water-quartz sand three-phase on three-phase internal-loop airlift reactor with the big ratio（height/ inner diameter= 22）of height to diameter, under normal temperature and atmosphere, at different par- ticle size,the effects of superficial gas velocity on gas holdup in riser,gas holdup in downcomer and solid holdup in riser, solid holdup in downcomer were investigated for the system, and the effects of vari- ous position of the riser on solid holdup were researched. The results showed that the gas holdup in riser and in downcomer increased with the increase of the superficial gas velocity at different particle size; the solid hold- up in riser gentle with the increase of superficial gas velocity at sands particles ≤0. 3 mm, the solid holdup in downcomer increased with the increasing of superficial gas velocity, when the solid holdup increased after the first drop with the increase of superficial gas velocity at sands particles 〉0. 3 mm while ≤1.2 mm, and the solid holdup in downcomer decreased with the increasing of superficial gas velocity; Solids holdup of the different volume fractions of solid particles with the increase of the axial height rather gently changes,can be uniformly distributed in the reactor;Gas holdup and solid holdup of the calculated and experimental values are in agreement, the average relative errors of gas holdup and solid holdup between calculated and experimental values were 6.32%,4. 56 %.