What is Refinery and how it works ?

Generally, crude petroleum is heated and changed into a gas. The hot gases are passed into the bottom of a distillation column and become cooler as they move up the height of the column. As the gases cool below their boiling point, they condense into a liquid.

The liquids are then drawn off the distilling column at specific heights, ranging from heavy resids at the bottom, raw diesel fuels in the mid-sections, and raw gasoline at the top. These raw fractions are then processed further to make several different finished products.

Although all fractions of petroleum find uses, the greatest demand is for gasoline. One barrel of crude petroleum contains only 30-40% gasoline. Transportation demands require that over 50% of the crude oil be "converted" into gasoline. To meet this demand some petroleum fractions must be converted to gasoline. This may be done by cracking — breaking down large molecules of heavy heating oil and resids; reforming — changing molecular structures of low quality gasoline molecules; and isomerization — rearranging the atoms in a molecule so that the product has the same chemical formula but has a different structure, such as converting normal butane to isobutene.

The word "petroleum" literally translates as "rock oil." It stems from the Greek word "petra," meaning rock, and the Latin word "oleum," meaning oil.

Crude oil is considered the "mother of all commodities" because of its use in the manufacturing of numerous products, including gasoline, synthetic fabrics, plastics and pharmaceuticals