Bubble Column

A bioreactor, which is in the shape of column, where the reaction medium is kept mixed and aerated by introducing of an air into the bottom is called bubble column. The bubble column is principally and predominantly used for the continuous operations, and it has no moving parts in contrast to the stirred tank reactor. The bubble column unit consists of an unpacked column section except the top short packed section which is used to remove foam. Via gas manifold, gas is introduced at the bottom of the column or by using the Garg gas mixing valve, if required the gas may be recycled. By means of external heat exchanger, the liquid can also be recycled. By fitting the lights around the columns the photochemical reactions can be carried out. This form of column has similar retention times when compared to continuous stirred tank reactor.  By adding up the short packed sections I the column, it is possible to enhance the retention time of the liquid phase, even though this leads to an increase in back mixing and a reduced gas loading.

The visually spectacular bubble columns feature watercourses of brightly coloured bubbles are rising up inside the water filled column. To create the soft mood, gentle light for the room and a focus point in the room, the glowing, gently changing colors from the bubble column is used. By mounting the angled mirrors at the rear of the unit the multi reflections are created and due to this, effect of the column is dramatically increased. And bubble columns can be changed to various colors by changing display mode that suits your sensory environment.

Multistage Bubble Column

For the purpose of slow gas-liquid reactions, multistage bubble column are very frequently used in the chemical industry. This allows the greater variation of the retention time of the liquid phase. This enables a cascade mode of operations to be used with well defined flow path but of no remixing with stages.  Multi stage bubble column can also be supplied with the constant or variable bubble formation layer heights. The constant bubble formation height in the column is based on the filter plate column which is fixed with the overflow heights and external liquid transfer lines. The liquid outlets are completely flooded and provided with restrictions, in case of the column with the variable bubble layer height.  The heat exchange coils can be fitted in the column and the temperature profile if required.

Questions:

• What is bubble column?
• What is multistage bubble column?