Lesson 11 - Carbon Dioxide Recovery Technology SAQ
This lesson allows you to test yourself on the material covered in the CO2 Recovery Technology lesson and to determine the level to which you have met the learning outcomes.
Suggested Response - Q7
**Describe the means by which a CO2 condenser purifies the CO2.
Response:
Any incondensable gases present with the CO2, such as oxygen and nitrogen, will not condense at the typical temperatures (-30 °C) used in the condenser. Instead, they will remain as gases when the CO2 condenses as a liquid and can be vented out of the condenser. If we think about this, it is a simple form of phase separation, i.e. within the condenser, we separate the incondensable (O2/N2) gas phase from the CO2 liquid phase. The liquid CO2 stream must be leaner in O2/N2 than the incoming CO2 gas stream – purification. Have a look at the diagram below.
Figure: Condenser schematic showing the purification of the liquid CO2 stream
To make this even simpler, we can consider something we are more familiar with – a glass of beer. As CO2 disengages or leaves the glass of beer in the form of nucleated bubbles (perhaps better known to us as beading), the concentration of CO2 in the beer must reduce. The beer becomes flat, i.e. the beer is becoming purer with respect to CO2 the longer we take to drink it.