循环曝气生物反应器的流体力学和传质特性

循环曝气生物反应器是一种具有曝气筒的用于废水处理的生物反应器,曝气筒外为下降区,常常填充填料作为微生物生长的载体。从循环液量(Vl)、环流液速(Uld)以及停留时间分布函数的量纲1方差(σ2θ)等方面研究了循环曝气生物反应器的流体力学性能和传质特性。研究表明,在下降区内有或无填料以及不同曝气筒截面积与反应器截面积比值(Ar/Are)的情况下,循环曝气生物反应器内的循环液量与气体流量之间均符合幂函数关系,Ar/Are对循环液量或循环液速的影响是先增后减,极值点为0.11。下降区放置填料降低了循环液量、循环液速,但提高了σ2θ,改善了液相传质性能。当Ar/Are为0.11时,在液体进料为0.1m3.h-1、气体流为量0.5～3.1m3.h-1的情况下,循环曝气生物反应器内的液相循环量是液相进料的9～28倍、σ2θ为0.9以上,循环曝气生物反应器具有较好的液相混合和稀释能力,可直接处理高浓度废水。

Study on the Holdup and Mass Transfer Performances for Gas-Liquid-Liquid System in a Screen Plate Column

The gas and dispersed phase holdups and mass transfer coefficients of liquid-iquid were determined for gas-liquid-liquid three phase system in a screen plate column. The flow pattern of gas-liquid-liquid three phase system was studied under different gas velocities. The shape factors showed the geometric properties of screen plates and the corrected drop characteristic velocities were introduced. The phase holdup in two phases was correlated. The research results indicated that mass transfer coefficient for liquid-liquid system in a column with screen plates and gas agitation was found to increase apparently.