# Fractional Distillation

19 de Dec de 2017
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### Fractional Distillation

• 1. ALL INDIA SENIOR SCHOOL CERTIFCATE EXAMINATION (2017-2018) DIVINE CHILD SCHOOL MEHSANA PROJECT TITLE : Fractional Distillation SUBMITTED BY: NAME:RAHILPARSANA CLASS:XIISCI.A
• 3. Certificate This is to certify that Rahil Parsana, a student of class XII, Divine child school has successfully completed the project titled FRACTIONAL DISTILLATION during the academic year 2017-2018 towards partial fulfillment of chemistry practical examination conducted by CBSE.
• 5. Acknowledgement Primarily I would thank god for being able to complete this project with success.Then I would like to thank my chemistry teachers Mr. Sanjeeb Sinha & Mr. Anand Tripathi, whose valuable guidance has been the ones that helped me patch this project and make if full proof success their suggestions and their instructions had served as the major contributor towards the completion of the project. Then I would like to thank my parents and friends who have helped me with their valuable suggestions and guidance has been helpful in various phases of the completion of the project. Last but not the least I would like to thank my classmates who have helped me a lot.
• 6. Table of Content  Introduction to Fractional Distillation  Mechanism  Uses and Application  Acknowledgement , Bibliography and References
• 7. Introductionto Fractional Distillation Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize. Generally the component parts have boiling points that differ by less than 25°C from each other under a pressure of one atmosphere. If the difference in boiling points is greater than 25°C, a simple distillation is used.
• 8. Mechanism The steps of fractional distillationare as follows: 1. You heat the mixture of two or more substances(liquids) with different boilingpointsto a high temperature. Heating is usually done with high pressure steam to temperatures of about 1112 degrees Fahrenheit / 600 degrees Celsius. 2. The mixture boils, forming vapour(gases); most substances go into the vapourphase. 3. The vapourenters the bottom of a long column (fractional distillation column)that is filled with trays or plates. The trays have many holes or bubblecaps(like a loosened cap on a soda bottle) in them to allow the vapourto pass through. They increase the contact time between the vapourand the liquidsin the column and help to collect liquidsthat form at variousheights in the column. There is a temperature difference across the column (hot at the bottom, cool at the top). 4. The vapourrises in the column. 5. As the vapourrises through the trays in the column, it cools. 6. When a substance in the vapourreaches a height where the temperature of the column is equal to that substance's boilingpoint, it will condense to form a liquid.(Thesubstance with the lowest boilingpoint will condense at the highest
• 9. point in the column; substances with higher boilingpoints will condense lower in the column.) 7. The trays collect the variousliquidfractions. 8. The collected liquidfractions may pass to condensers, which cool them further, and then go to storage tanks, or they may go to other areas for further chemical processing Fractionaldistillationis useful for separating a mixture of substances with narrow differences in boilingpoints, and is the most important step in the refining process.
• 10. Uses and Applications  Fractional distillation of Air Air is filtered to remove dust, and then cooled in stages until it reaches 200o C. At this temperature it is a liquid. We say that the airhas been liquefied. Here's what happensas the air liquefies (note that you do not need to recall the boilingpointsof the different gases):  Water vapourcondenses, and is removed using absorbent filters  Carbon dioxide freezes at -79o C, and is removed  Oxygen liquefies at -183o C  Nitrogen at -196o C. The liquidnitrogen and oxygen are then separated by fractional distillation. The liquefiedair is passed into the bottom of a fractionating column. Just as in the columns used to separate oil fractions, the column is warmer at the bottom than it is at the top. The liquidnitrogen boilsat the bottom of the column. Gaseous nitrogen rises to the top, where it is piped off
• 11. and stored. Liquid oxygen collects at the bottom of the column. The boiling pointof argon the noblegas that forms 0.9 percent of the air is close to the boilingpoint of oxygen, so a second fractionatingcolumn is often used to separate the argon from the oxygen.
• 12. (Typical industrial fractional distillation columns.) (Diagram of a typical, large-scale industrial distillation tower.)
• 14. Crude oil is a mixture of hydrocarbons. The crude oil is evaporated and its vapour condense at different temperature in the fractionating column. Each fraction contains hydrocarbon molecules with similar number of carbon atom and a similar range of boiling points. The diagram above summarizes the main fractions from crude oil and their uses, and the trends in properties. Note that the gases leave at the top of the column, the liquids condense in the middle and the solids stay at the bottom. As you go up the fractionating column, the hydrocarbons have:  Lower boiling points.  Lower viscosity.  Higher flammability. The oil refining process starts with a fractional distillation column. Very few of the components come out of the fractional distillation column ready for market. Many of them must be chemically processed to make other fractions. For example, only40% of distilled crude oil is gasoline; however, gasoline is one of the major products made by oil companies. Rather than continually distilling large quantities of crude oil, oil companies chemically
• 15. process some other fractions from the distillation column to make gasoline; this processing increases the yield of gasoline from each barrel of crude oil.
• 19. Bibliography  https://en.m.wikipedia.org/wiki/Fractional_distillation  https://en.m.wikipedia.org/wiki/Distillation  NCERT 11th Chemistry part II  http://www.bbc.co.uk/schools/gcsebitesize/science/aqa /earth/earthsatmosphererev6.shtml  http://science.howstuffworks.com/environment/energy /oil-refining4.htm