After crude oil is extracted from the earth, it undergoes a process called fractional distillation in a refinery. This process separates crude oil into different hydrocarbon fractions based on their boiling points. Here’s a breakdown of what happens:
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Heating: The crude oil is heated in a distillation tower, causing it to vaporize.
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Fractionation: As the vapors rise up the distillation column, they cool and condense at different heights based on their boiling points. The column is designed so that the temperature decreases gradually from bottom to top.
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Separation: Each fraction corresponds to a specific range of boiling points and is collected at different levels of the column. These fractions include:
- Gases (like propane and butane) at the top.
- Naphtha (used for gasoline) slightly lower.
- Kerosene (used as aviation fuel and in lamps).
- Diesel fuel further down.
- Heavy oils and residual oils at the bottom, which may be used for lubricants and asphalt.
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Further Processing: Each of these fractions can undergo additional processing, such as cracking, reforming, and treating, to produce various petroleum products.
By this method, crude oil is effectively transformed into valuable products used in transportation, heating, and as raw materials in the petrochemical industry.