Fractional Distillation of Crude Oil

A crude oil sample is heated and liquid fractions are collected as temperature rises, modeling how refineries separate petroleum by boiling range.

1. Gather a distillation setup (heat source, round-bottom flask, fractionating column, thermometer at the vapor takeoff, condenser, receiver), crude oil sample, balance, graduated cylinders or pipets, timers, and data sheets.
2. Measure and record the crude oil volume placed in the distillation flask; weigh the crude-filled flask to determine the crude mass and calculate the crude density.
3. Assemble the apparatus securely with clamps; ensure the thermometer bulb sits at the level of the side arm so it reads vapor temperature, not liquid temperature.
4. Begin gentle heating to produce a steady distillation drip rate; keep the column insulated if available so separation improves.
5. Collect the first fraction over a defined temperature window; record start and end temperatures for the cut and label the receiver with the fraction number.
6. Increase heat gradually to obtain subsequent fractions, defining each by its boiling range; avoid overheating or bumping and maintain a moderate distillation rate.
7. Continue until no more distillate is obtained or the maximum target temperature is reached; allow heavy residue to cool before handling.

The Distillation of Crude Oil - Science Skool:

Crude Oil Distillation: A Billion-Dollar Lab Experiment - Wheeler Scientific:

📄 Oil Distillation - Jim Lokken: https://www.tsfx.edu.au/resources/P_-_Fract_Dist_-_Prince_William_Sound_RCAC_-_Track_2_9-10_-_Oil_distillation.pdf?srsltid=AfmBOopKYZqoGEq-UjJpkMI77di9lPy6B7Ilh9cVpp67fHaucqRjYjgd

• Add a proper fractionating column and insulation to compare simple vs fractional distillation performance.
• Characterize fractions further using simple flammability tests by a trained instructor with micro-quantities in a fume hood.

• Wear splash goggles, lab coat, and nitrile gloves; tie back hair and secure loose clothing.
• Conduct all work in a fume hood or very well ventilated space; crude oil contains volatile, toxic, and odorous compounds including sulfur species.
• Use an electric heating mantle or regulated hot plate; avoid open flames due to flammable vapors.
• Verify all joints are secure; use Keck clips and support stands to prevent collapse or tipping.
• Keep the distillation rate moderate to prevent flooding of the column and bumping; use boiling chips unless using a spinning band or similar system that prohibits them.
• Ensure cooling water flows before heating; check that the condenser outlet is directed into a secured receiver.
• Do not distill to complete dryness; leave residue to avoid overheating heavy ends that can decompose.
• Label and cap all collected fractions promptly; keep away from ignition sources.
• Dispose of crude residues and fractions as hazardous waste according to local regulations; never pour hydrocarbons down the drain.

• What condition must be met for two substances to be separated by fractional distillation? (They must have different boiling points under the same pressure.)
• How does molecular size generally relate to volatility in petroleum fractions? (Lower molecular weight fractions are more volatile and boil at lower temperatures.)
• How can heavy gas oils be converted into gasoline-range products industrially? (By cracking and reforming, often with catalysts and sometimes with hydrogen, to make smaller, higher-octane molecules.)
• What observations might indicate sulfur compounds in a crude or fraction? (Pungent or rotten-egg odors, darker color, heavier character; analytical tests would confirm.)