Question

Explain how CO₂ stripping works (you may draw a picture to help you explain it, but it is not required). Why is removing CO₂ important?

Answer 1

Stripping is physical seperation process where one or more components are removed from a liquid stream by a vapour stream.The liquid and vapour streams can have co-current and counter current flows.

Stripping is conducted in trayed columns which consist of a vertical column with liquid flowing in the top and out the bottom.The vapour phase enters in the bottom of the column and exists out of the top.Inside of the columns are trays or plates.These trays force the liquid to flow back and forth horizontally while the vapour bubbles up through holes in the trays.The purpose of these trays is to increase the amount of contact area between the liquid and vapour phases.

Co2 stripping is based on the difference in concentration gradient between bulk dissolved Co2 concentration and the saturation dissolved Co2 concentration.

The influent water from the culture tank with the high Co2 enters at the top of the column and is distributed for uniform loading.The column internal may have water breakup of some sort like plastic packing.As the water passes through the column air is blown through the column and it exists having picked up Co2 from the water.

Co2 is to be removed because it can be toxic,i t can be used in other process such as in methanol plants,it can be used as downstream in urea production,it also acts as compression loop hence increasing the compression cost.