Three Illustrations Of The Bubble Column

As it can be seen in the previous figure, the Bubble Column PBR is a simple conceptual design. The figure simply illustrates the basic flow in the column. The gas enters the bottom of the column through a diffuser causing the gas to break into thousands of small bubbles making it easier for the algae to absorb the carbon dioxide in the gas. Once the algae have consumed as much carbon dioxide as it can, it releases oxygen in the form of gas, which leaves the column through the opening in the top and returns to the atmosphere [7]. The three illustrations following the Bubble Column show the other three types of Vertical Column PBRs. Illustration "B" is an example of an "Internal Loop Airlift" PBR [7]. The "Internal Loop Airlift" PBR works similarly to the Bubble Column as the gas enters the column through the bottom and leaves through the …show more content…
However, unlike any other type of photo-bioreactor, it uses an internal column to house the upward gas flow. As the gas leaves the center column, it causes an upward flow in the algae and water that fills the column allowing it to over-flow the center column and return to the bottom to be circulated again as more gas enters the center column [7]. Illustration "C" shows an example of a "Split-Column Airlift" PBR [7]. This PBR works in the same way that the Internal Loop Airlift PBR does except that the vertical flow is on one side of the column, divided by a flat wall of the column [7]. Illustration "D" is an example of an "External-Loop Airlift" PBR [7]. Like the "It also works the same way as the Internal Loop Airlift in respect to the flow. However, the flow back down to the bottom of the column takes place in an external tube connecting from the top to the bottom of the