What is the essence of gas-liquid mass transfer? Could some expert explain this in detail?
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For example: In the process of methanol absorbing carbon dioxide from gas, how does carbon dioxide enter the methanol? And how is the partial pressure of carbon dioxide in the solution defined? What is the difference between the partial pressure of carbon dioxide in a solution and its partial pressure in the gas phase, and how does mass transfer occur between them? Is the rate at which methanol absorbs carbon dioxide solely dependent on the partial pressure of carbon dioxide? But there are other molecules in the gas as well, and there are many forces acting between these molecules; doesn’t that affect the dissolution of carbon dioxide? I really can’t figure it out; could some expert please explain it?
To understand this, you first need to grasp two concepts: the basic principles of mass transfer; the absorption process
“”What is the difference between the partial pressure of carbon dioxide in the solution and its partial pressure in the gas phase? “For this type of physical absorption, the difference between the two lies in the driving force for mass transfer.”
There is a limit to the concentration of solute that can be absorbed by a solution; as long as it is not saturated, it can theoretically continue to absorb solute until it reaches the saturation level possible under those temperature and pressure conditions. Here, it can be understood as a difference between the carbon dioxide partial pressure in the solution and that in the gas phase.
So, when the partial pressure of carbon dioxide in the gas phase is greater than that in the solution, do the carbon dioxide molecules in the solution transfer to the gas phase?