in a fractionation column or contactor when the gas upwards extract the gas downwards and the liquid downwards extract the liquid upwards, what is this phenomenon calle?
First, provide more detail on your question. Notice my first response is a question, because I am uncertain of your question. There are two other responses that are different, so I must not be the only one who has doubts.
ok, for example in the stabilizer column, the gas produced in the re-boiler enters in the middle of the stabilizer to extract any gases which could be with the downwards condensate, and the same with condensate to extract any condensate which could be with gas upwards.
You've given a very elementary explanation of a separation tower. Yes liquid goes down vapor goes up they equilibrate and continue up and down.
What is the question?
Basic transfer phenomenon. There is heat and mass transfer occurring at each contact stage as determined by equilibrium between components in your streams.
What is the purpose of your question? Are you working in the petrol industry?
Ideally, vapor rises from the stage below, where it mixes with the liquid from the stage above. The vapor from the stage below supplies the heat to vaporize the light components in the equilibrium mixture and the liquid from the stage above supplies the heat sink or cooling to condense the heavy components in the equilibrium mixture.
I'm sure there are textbooks and internet sites that explain it better than me, but that's how I think of it.
Any system doing what nevine asks about refers to mass transfer, sometimes accompanied by heat and momentum transfer. There are many processes that deal with mass transfer in gas-liquid, liquid-liquid, etc., without chemical interaction. I recommend Perry's Chemical Engineers' Handbook for a review of the subject.