Gas holdup, liquid circulating velocity and mass transfer properties in a mini-scale external loop airlift bubble column
Gas holdup, liquid circulating velocity and mass transfer properties in a mini-scale external loop airlift bubble column
复制标题
微型外循环气升泡罩塔中的含气率、液体循环速度和传质特性
DOI：
10.1016/s0009-2509(03)00207-0
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发表时间：
2003
影响因子：
4.7
通讯作者：
K. Nakao
中科院分区：
文献类型：
--
作者：
Shaoqing Wang;Y. Arimatsu;Kenichi Koumatsu;Keiji Furumoto;M. Yoshimoto;K. Fukunaga;K. Nakao
由于上升管和下降管之间存在液体循环流动，外循环气升式泡罩塔被认为是一种有前途的气液或气液固生物反应器。微型色谱柱对于高度专业化的材料（例如在两相或三相系统中使用的精细化学品、先进生物产品和生物催化剂）的工艺研究和开发非常有用且高效。在这项工作中，设计并表征了体积为 20 ml 的微型玻璃柱。通过用数码相机拍摄的照片测量体积膨胀来获得立管中的含气率εG。通过分析摄像机拍摄的图像，观察示踪粒子在降液管中行进固定距离（3.5cm）所需的时间，从而测量液体循环速度UL。气液体积氧传递系数kLa和液固氧传递系数kS采用我们之前的方法测定，其中悬浮在柱中的固定化葡萄糖氧化酶凝胶珠催化葡萄糖的空气氧化，获得溶解氧的伪稳态浓度和相应的葡萄糖消耗恒定速率。结果表明，即使是这样的小型外循环泡罩塔，也可以根据我们之前为实验室到中试规模塔提出的相关性，在含气量、液体循环速度和传质特性方面进行表征。
The external loop airlift bubble column has been regarded as a promising type of gas–liquid or gas–liquid–solid biooreactor because of the liquid circulating flow between the riser and downcomer. A mini-scale column is useful and efficient in the process research and development for highly specialized materials such as fine chemicals, advanced bioproducts and biocatalysts utilized in two or three phase system. In this work, a mini-scale glass column of 20 ml in volume was designed and characterized. The gas holdup εGin the riser was obtained by measuring the volume expansion through photographs taken with a digital camera. The liquid circulating velocity ULwas measured by observing the time required for a tracer particle to travel a fixed distance (3.5 cm ) in the downcomer through analysis of the images taken by a video camera. The gas–liquid volumetric oxygen transfer coefficient kLa and liquid–solid oxygen transfer coefficient kSwere determined by our previous method in which the air oxidation of glucose was catalysed by the immobilized glucose oxidase gel beads suspended in the column to obtain a pseudo steady state concentration of the dissolved oxygen and the corresponding constant rate of glucose consumption. It was shown that even such a mini-scale external loop bubble column could be characterized in terms of gas holdup, liquid circulating velocity and mass transfer properties according to our previous correlations proposed for the bench to pilot scale column.