摘要
在直径为100mm,高3000mm 并有内径为2mm 单喷嘴的气升式外循环生物反应器内,以藻酸钠溶液为高粘度模拟介质,在较广泛的操作条件下,实验测定了反应器内液体的循环时间、平均气含率、局部气含率及氧的体积传质系数随介质粘度、表观气体速度的变化。并对实验结果进行了经验关联。
Experimental studies on mass transfer in an airlift bioreactor with highly viscous media were carried out.The airlift bioreactor with external loop used in this work consisted of a upflow column (Ф100 mm,3 m high),a downcomer(70 mm in diameter)and a single nozzle(Ф2 mm internal diameter).The solutions with varied concentration of sodium alginate were employed as highly viscous media.Under various operating conditions the measured liquid circulation time, mean gas holdup,local gas holdup and mass transfer coefficient of oxygen from gas to liquid proved dependent upon the liquid viscosity and superfacial gas velocity.Experimental results indicate that the liquid circulation time,t,decreases with increasing superfacial gas velocity and that the mean gas holdup,e,and local gas holdup,∈,increase as superfacial gas velocity is increased but decrease slightly with increase of liquid viscosity.The volumetric mass transfer coefficient,k_Lα,is observed to increase linearly with the increase of superfacial gas velocity and drops drastically as the medium becomes more viscous.In the range of experimental conditions,those parameters mentioned above can be approximately expressed as follows: t=12.6u_g^(-0.178)(s) for water system ε=4.71u_^(1.33)μ^(-0.075) k_Lα=4.42u_g^(1.66)μ^(-0.063)(s^(-1)) forμ<100 MPa·s k_Lα=4.69u_g^(0.194)μ^(-1.38)(s^(-1)) forμ≥100 MPa·s where u_g is the superfacial gas velocity in m/s and μ is the liquid viscosity in MPa·s.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
1991年第2期136-142,共7页
Chemical Reaction Engineering and Technology
关键词
气升式
生物反应器
气液传质
Gas-liquid mass transfer
Airlift bioreactor
Highly viscous fluid
Loop reactor
