What is Gas Stripping?

Gas stripping is a physical separation process where one or more volatile components are removed from a liquid stream by a gas stream. This mass transfer process relies on the concentration gradient between the liquid phase and the gas phase. In water treatment, this is most commonly used to remove Volatile Organic Compounds (VOCs), dissolved gases like oxygen or carbon dioxide, and ammonia from wastewater.

How to Use This Calculator

To calculate the stripping efficiency, you need to provide four primary inputs:

• Henry's Law Constant (H'): This is the dimensionless ratio of the concentration of a compound in air to its concentration in water at equilibrium.
• Gas Flow Rate (Qg): The volume of air or gas introduced into the system per unit of time.
• Liquid Flow Rate (Ql): The volume of water or liquid being treated per unit of time.
• Transfer Units (Nt): A measure of the size/capability of the stripping tower or contactor.

Understanding the Stripping Factor (S)

The Stripping Factor is defined as S = H' * (Qg / Ql). For effective removal, the Stripping Factor should typically be greater than 1.0. If S is less than 1.0, the removal efficiency is limited by the thermodynamic equilibrium, and complete removal becomes impossible regardless of the tower height.

Frequently Asked Questions (FAQs)

Does temperature affect gas stripping?

Yes, significantly. Henry's Constant increases with temperature, meaning volatile compounds are easier to strip from water when the water is warmer.

What is the difference between stripping and aeration?

While aeration introduces air into water, gas stripping specifically refers to the intentional removal of solutes using a controlled gas flow, often inside a packed tower or column to maximize the surface area for mass transfer.