Mammoth Memory

Fractionating column for crude oil: condensing points and temperature

 

Within the fractionating column, it’s hot at the bottom of the column and gets gradually cooler towards the top. Smaller molecules require less energy (heat) than larger molecules to change them from liquid to vapour. The smaller molecules condense (change back to liquid) further up the column. This is how the different sized molecules (fractions) are separated.

Big hydrocarbons are found at the bottom where it is hot and small hydrocarbons where it is cooler at the top

 

From the top to the bottom, the hydrocarbon molecules get bigger as the temperature of the column gets hotter.

 

For more information on hydrocarbons and to see what small C1 and larger hydrocarbon molecules look like, follow the link to our hydrocarbons page.

But as a quick summary, see the following:

Methane CH4: Boiling point -162⁰C (-259⁰F)

Methane has a boiling point of minus 162⁰C and is gathered at the top off the chamber

Ethane C2H6 – Boiling point -89⁰C (-127⁰F)

Ethane has a boiling point of -89⁰C and is siphoned off in the chamber

 

Propane C3H8: Boiling point -42⁰C (-44⁰F)

Propane has a boiling point of -42⁰C and is siphoned off in the chamber

Normal butane C4H10: Boiling point -0.51⁰C (31⁰F)

Butane has a boiling point of -0.51⁰C and is siphoned off in the chamber

 

Isobutane C4H10: Boiling point -12⁰C (11⁰F)

Isobutane has a boiling point of -12⁰C and is a mixture of propane and butane

 

Heneicosane C21H44: Boiling point 100⁰C (212⁰F)

Heneicosane has a boiling point of 100⁰C

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