Because liquid is heavier than vapours so gravity pull them back.
A fractionating column works by heating a mixture to its boiling point, causing the components with lower boiling points to vaporize first. As the vapor rises through the column, it condenses on cooler surfaces and collects at different levels based on their boiling points. This separation process allows for the collection of different components from the mixture.
This is an installation used for separation by distillation.
numerator
The top of an oil fractionating column is where the lighter hydrocarbon fractions, such as gases and light liquids, are collected and removed from the column. This process separates the different components of crude oil based on their boiling points.
why does temprature fall down toward the end of the fractional column
A tall fractionating column has 2 main parts 1- tall :usualy mean high pressure 2-fractionating column: means sepration of a componant usualy you will find something like propane fractionation means removing propane I hope I have cleared some of the meaning
The fractionating column takes advantage of the fact that the different parts (fractions), which form the mixture known as crude oil, boil (or evaporate) at different temperatures. The fractionating column is effectively an advanced distillation process. The bottom part of the column is the hottest part where heavy fractions such as tar do not evaporate, but lighter fractions will boil off and travel upwards through the column. The top part of the column is the coolest part where only the lightest fractions form a vapour. At various points between the top and bottom, the different fractions condense into liquids at different temperatures and can be drawn off in purified liquid form.
and why?
The outer jacket on a fractionating column is used to insulate against heat loss from the inner jacket during distillation.
The boiling point is lower.
They are denser.
Duncan XYZ oil would be tapped off closer to the top of a fractionating column because it is viscous (runny)