DESCRIPTION

Technical Description

In the airlift reactor, air bubbles mix the reactor contents. At the same time, the air bubbles serve to supply oxygen to the microorganisms.

Compressed air enters the reactor at the bottom and ascends as small air bubbles. Part of the oxygen contained in the air is dissolved into the water in this process. The water moves upwards due to the lower density of the air/water mixture. The air bubbles leave the water at the head of the reactor. Due to the higher density, the water with the dissolved oxygen sinks again in the outer part of the reactor. The speed is adjusted via the flow rate of the air. Nitrogen can be used to remove oxygen from the water. This is required in order to be able to determine the mass transfer coefficient of oxygen in water.

Learning Objectives / Experiments

Influence of the superficial gas velocity on:
* gas content
* mass transfer coefficient
* mixing time and superficial fluid velocity