Heating is usually done with high pressure steam to a temperature of 600 degrees Celsius. .
2. The mixture then boils, forming vapour. .
3. The vapour enters the bottom of the fractional distillation column which is filled with trays or plates (the trays contain bubble caps to allow vapour to pass through and they also increase the contact time between the vapour and the liquids in the column).
4. The vapour rises in the column.
5. Rising through the column, the vapour cools.
6. When a substance in the vapour reaches a height where the temperature of the column is equal to that substance's boiling point, it will condense to form a liquid (The substance with the lowest boiling point will condense at the highest point in the column; substances with higher boiling points will condense lower in the column.). .
7. The trays collect the various liquid fractions.
8. The trays are then stowed away and undergo further processing.
Very little components come out of the fractional distillation column ready for to be sold. Only 40% of distilled crude oil is gasoline; however, gasoline is one of the main products produced by oil companies. Rather than continually distilling large quantities of crude oil, oil companies chemically process some other fractions from the distillation column to turn into gasoline; this processing increases the amount of gasoline obtained from each barrel of crude oil.
One fraction may be changed into another by any one of three methods, these being cracking, unification and alteration. Cracking involves breaking large hydrocarbons into smaller pieces. Cracking can be achieved using one of three techniques: thermal cracking, catalytic cracking, or hydrocracking. Thermal cracking uses heat/pressure to break down the molecules. Catalytic cracking uses a catalyst, heat and and pressure and hydrocracking uses hydrogen and a catalyst and very high pressure and temperature to break down large molecules into the gasoline and diesel fuel range.
