Fractional Distillation of Crude Oil
Crude oil is separated into fractions by boiling point range.
Crude oil is separated into fractions by boiling point range.
Crude oil is a mixture of hydrocarbons that is separated in a refinery by fractional distillation. The oil is heated until most of it vaporizes and is fed into a tall column that is hot at the bottom and cooler at the top. As vapours rise they condense on trays at the level where their boiling point is reached, forming fractions such as refinery gas, petrol, kerosene, diesel, fuel oil and bitumen. Heavier fractions with longer chains boil at higher temperatures and are collected lower in the column.
Key ideas: Crude oil is heated to about 400 C and fed into a column hotter at the bottom and cooler at the top. Fractions by boiling range: refinery gas below 40 C, naphtha and petrol 40 to 200, kerosene 175 to 275, diesel 250 to 350, then residue. Larger molecules have stronger London forces, higher boiling points, higher viscosity and lower flammability.
Common mistakes and connections: Students say crude oil is separated into pure compounds; each fraction is still a mixture. Another error is saying molecules crack in the column. The higher up a fraction is collected, the shorter the chains. Links to cracking to meet demand for petrol, intermolecular forces and petrochemicals.
Fractions leave the column at different heights: lighter, lower-boiling fractions rise highest and heavy residues stay at the bottom. The interactive lesson shows this as a live animation or chart.
Bitumen is collected at the bottom of the column, while liquefied petroleum gas is collected at the top.
Crude oil is separated into fractions by boiling point range.
Fractional Distillation of Crude Oil is a beginner topic in Organic Chemistry. It needs no earlier chemistry lessons and is a good starting point.
Study these earlier topics in Organic Chemistry first: Free Radical Halogenation, Combustion of Hydrocarbons, Cracking.
The next topics in Organic Chemistry are Octane Number and Electrophilic Addition.
Yes. The interactive lesson includes a self-check question on Fractional Distillation of Crude Oil, and the Organic Chemistry quiz draws on every topic in this area.
Fractional Distillation of Crude Oil is topic 45 of 148 in Organic Chemistry.