In the past few weeks, we’ve been learning about absorption and stripping processes in my mass transfer class. Absorption and stripping processes are both used to separate mixtures. However, there are some big similarities and difference between the two.
- Used to separate gas mixtures
- materials transferred from gas to liquid
- remove impurities, contaminants, pollutants, or catalyst poisons from a gas
- recover valuable chemicals
- Used to separate liquid mixtures
- coupled with absorption to recover materials back after a absorption process
- materials transferred from liquid to gas
A good everyday example for stripping is the purification process of ground water to drinkable water. Ground water would flow into the stripper containing volatile organic compounds, and it will be stripped in a trayed tower with air to produce drinking water that will meet United States Environmental Protection Agency.
Below are some common representative, commercial application of absorption. Solute the substance that is transferred from the gas phase to the liquid phase. The absorbent is the solvent that is used to absorb the target gas from gas into the liquid. Physical absorption means that there’s no reaction taking place. It is merely a mass transfer between the two substance. On the other hand, chemical absorption means that there’s a reaction happening when mass transfer takes place.
For both absorption and stripping processes, it’s important to pay attention to the amount of stages used. Because it will determine the economical cost. Money is always the number one thing you want to consider whenever you are building a absorption column or stripper. Your company will be happy if you can minimize the cost for them.