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Fractional Distillation is the separation of a mixture into its component parts, or fractions, such as in separating Chemical_compoundby their Boiling_pointby heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of Distillation. Generally the component parts boil at less than 25 °C from each other under a pressure of one atmosphere (Atmosphere_(unit)). If the difference in boiling points is greater than 25 °C, a Distillationis used. File:Fractional_distillation_lab_apparatus.svgFractional distillation apparatus using a Liebig_condenser. A Conical_flaskis used as a receiving flask. Here the distillation head and Fractionating_columnare combined in one piece.Answers.com

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As an example, consider the distillation of a mixture of Waterand Ethanol. Ethanol boils at 78.4 °C while water boils at 100 °C. So, by gently heating the mixture, the most volatile component will concentrate to a greater degree in the vapor leaving the liquid. Some mixtures form Azeotrope, where the mixture boils at a lower temperature than either component. In this example, a mixture of 96% ethanol and 4% water boils at 78.2 °C, being more Volatility_(chemistry) than pure ethanol. For this reason, ethanol cannot be completely purified by direct fractional distillation of ethanol-water mixtures.

The apparatus is assembled as in the diagram. (The diagram represents a batch apparatus, as opposed to a continuous apparatus.) The mixture is put into the round bottomed flask along with a few Boiling_chip(or a Teflon coated magnetic stirrer bar if using magnetic stirring), and the fractionating column is fitted into the top. As the mixture boils, vapor rises up the column. The vapor Condensationon the glass platforms, known as Theoretical_tray, inside the column, and runs back down into the liquid below, Refluxdistillate. The column is heated from the bottom. The efficiency in terms of the amount of heating and time required to get fractionation can be improved by insulating the outside of the column in an insulator such as wool, aluminum foil or preferably a vacuum jacket. The hottest tray is at the bottom and the coolest is at the top. At steady state conditions, the vapor and liquid on each tray are at Vapor-liquid_equilibrium. Only the most volatile of the vapors stays in Gasform all the way to the top. The vapor at the top of the column, then passes into the condenser, which cools it down until it liquefies. The separation is more pure with the addition of more trays (to a practical limitation of heat, flow, etc.) The condensate that was initially very close to the azeotrope composition becomes gradually richer in water. The process continues until all the ethanol boils out of the mixture. This point can be recognized by the sharp rise in temperature shown on the Thermometer.

Typically the example above now only reflects the theoretical way fractionation works. Normal laboratory fractionation columns will be simple glass tubes (often vacuum jacketed, and sometimes internally Silvering) filled with a packing, often small glass helices of 4 to 7 mm diameter. Such a column can be calibrated by the distillation of a known mixture system to quantify the column in terms of number of theoretical plates. To improve fractionation the apparatus is set up to return condensate to the column by the use of some sort of reflux splitter (reflux wire, McIntire Head, Magnetic swinging bucket, etc.) - a typical careful fractionation would employ a reflux ratio of around 10:1 (10 parts returned condensate to 1 part condensate take off).

In laboratory distillation, several types of condensers are commonly found. The Liebig_condenseris simply a straight tube within a Water_jacket, and is the simplest (and relatively least expensive) form of condenser. The Graham_condenseris a spiral tube within a water jacket, and the Allihn_condenserhas a series of large and small constrictions on the inside tube, each increasing the surface area upon which the vapor constituents may condense.

Alternate set-ups may utilize a "cow" or "pig" which is connected to three or four receiving flasks. By turning the "cow" or "pig", the distillates can be channeled into the appropriate receiver. A Perkin_triangleis versatile piece of apparatus that can also be used to collect distillation fractions which does not require a "cow" or "pig" adapter. A Perkin_triangleis most often used where the distillates are Air-sensitiveor where the fractions distill and are collected under reduced pressure, but can be used for a simple and fractional distillation.

Vacuum_distillationsystems operate at reduced pressure, thereby lowering the boiling points of the materials. Note that the use of Boiling_chipwill not work at reduced pressures.

Industrial distillationFile:Colonne_distillazione.jpgImage 2: Typical industrial fractional distillation columns

Distillation is the most common form of separation technology used in Oil_refinery, Petrochemicaland Chemical_plantand Natural_gas_processingplants.Answers.comAnswers.comIn most cases, the distillation is operated at a Continuous_distillationSteady_state. New feed is always being added to the distillation column and products are always being removed. Unless the process is disturbed due to changes in feed, heat, ambient temperature, or condensing, the amount of feed being added and the amount of product being removed are normally equal. This is known as continuous, steady-state fractional distillation.

Industrial distillation is typically performed in large, vertical cylindrical columns known as "distillation or fractionation towers" or "distillation columns" with diameters ranging from about 65 centimetres to 6 metres and heights ranging from about 6 metres to 60 metres or more. The distillation towers have liquid outlets at intervals up the column which allow for the withdrawal of different fractions or products having different Boiling_pointsor boiling ranges. By increasing the temperature of the product inside the columns, the different hydrocarbons are separated. The "lightest" products (those with the lowest boiling point) exit from the top of the columns and the "heaviest" products (those with the highest boiling point) exit from the bottom of the column.

For example, fractional distillation is used in Oil_refineryto separate Crude_oilinto useful substances (or fractions) having different Hydrocarbonsof different boiling points. The crude oil fractions with higher boiling points:

File:Distillation_Column.pngFigure1: Diagram of a typical industrial distillation tower

Large-scale industrial towers use Refluxto achieve a more complete separation of products. Reflux refers to the portion of the condensed overhead liquid product from a distillation or fractionation tower that is returned to the upper part of the tower as shown in the schematic diagram of a typical, large-scale industrial distillation tower. Inside the tower, the reflux liquid flowing downwards provides the cooling needed to condense the vapors flowing upwards, thereby increasing the effectiveness of the distillation tower. The more reflux is provided for a given number of Theoretical_plate, the better the tower's separation of lower boiling materials from higher boiling materials. Alternatively, the more reflux provided for a given desired separation, the fewer theoretical plates are required.

Fractional distillation is also used in air separation, producing Liquid_oxygen, Liquid_nitrogen, and highly concentrated Argon. Distillation of Chlorosilanealso enable the production of high-purity Siliconfor use as a Semiconductor.

In industrial uses, sometimes a packing material is used in the column instead of trays, especially when low pressure drops across the column are required, as when operating under vacuum. This packing material can either be random dumped packing (1-3" wide) such as Raschig_ringor Structured_packing. Typical manufacturers are Koch, Sulzer and other companies. Liquids tend to wet the surface of the packing and the vapors pass across this wetted surface, where Mass_transfertakes place. Unlike conventional tray distillation in which every tray represents a separate point of Vapor_liquid_equilibriumthe vapor liquid equilibrium curve in a packed column is continuous. However, when modeling packed columns it is useful to compute a number of Theoretical_plateto denote the separation efficiency of the packed column with respect to more traditional trays. Differently shaped packings have different surface areas and void space between packings. Both of these factors affect packing performance.

Design of industrial distillation columnsApparatus
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How do you separate kerosene from crude oil?

Kerosene can be separated from crude oil through a process known as fractional distillation. During this process, crude oil is heated in a fractional distillation column, and the different components of the oil vaporize at different temperatures. Kerosene has a boiling point that is lower than most other components in crude oil, allowing it to be collected and separated from the other fractions.


Is oil refining same as fractional distillation?

Oil refining is a process that involves multiple steps to separate and process crude oil into different petroleum products like gasoline, diesel, and jet fuel. Fractional distillation is a key technique within the overall oil refining process, where the crude oil is heated to separate its components based on their boiling points. So, while oil refining encompasses various processes beyond just fractional distillation, fractional distillation is a crucial part of oil refining.


How do you process oil?

It is heated through a furnace which is connected to a large tube. The different hydrocarbons in the Crude Oil will condense at different temeratures. The distilling tube is made so that there are different sections for the different temperatures that the crude oil will condense at. It then catches each different hydrocarbon.


What are the main steps needed to obtain pure ethanol from the mixture produced after three days?

To obtain pure ethanol from a fermentation mixture, first, perform a distillation process to separate the ethanol from water and other components based on their boiling points. This involves heating the mixture to vaporize the ethanol, then cooling the vapor to collect it as a liquid. Following distillation, further purification may be achieved through techniques like fractional distillation or azeotropic distillation to remove residual water and impurities. Finally, drying agents or molecular sieves can be used to achieve the desired purity level of ethanol.


How will you separte the mixture containing petrol and kerosene which are miscible with each other?

The mixture can be separated using fractional distillation, as petrol and kerosene have different boiling points (petrol has a lower boiling point than kerosene). By heating the mixture, the components will vaporize at different temperatures and can be collected separately as they condense back into liquids.

Related Questions

How do you separate kerosene from crude oil?

Kerosene can be separated from crude oil through a process known as fractional distillation. During this process, crude oil is heated in a fractional distillation column, and the different components of the oil vaporize at different temperatures. Kerosene has a boiling point that is lower than most other components in crude oil, allowing it to be collected and separated from the other fractions.


Is oil refining same as fractional distillation?

Oil refining is a process that involves multiple steps to separate and process crude oil into different petroleum products like gasoline, diesel, and jet fuel. Fractional distillation is a key technique within the overall oil refining process, where the crude oil is heated to separate its components based on their boiling points. So, while oil refining encompasses various processes beyond just fractional distillation, fractional distillation is a crucial part of oil refining.


Why cant you separate crude oil by using simple distillation?

Crude oil is a complex mixture of hydrocarbons with varying boiling points. Simple distillation can only separate compounds with significantly different boiling points, while the components of crude oil have boiling points that are too close together for effective separation. Fractional distillation, which uses repeated distillation steps, is utilized to separate the components of crude oil effectively.


What is the steps of the fractional distillation of crude oil?

The major steps include:Desalting - removing salt, water, dirt and other impuritiesCrude and vacuum distillation - start separating the crude oil into separate productsConversion - modifying the composition of the productsBlending - putting together measure amounts of products to make something that does a specific job


What is crude condensate?

this can be your first fraction of distillation. In general crude means that the half fabricate isn't pure enough and more purification steps are required


What is the difference between simple distillation and fractional distillation?

Simple distillation refers to the "simple" separation of a solid and a liquid by evaporating the liquid and collecting it after it passes through a condenser to be changed into a liquid state. Fractional distillation refers to the more complex way of separation, usually involving a liquid/liquid mixture (eg. ethanol and water). these can be separated since they both have different boiling points. When this mixture is heated the ethanol having the lowest boiling point boils off first, followed by the water. However the fractional coulomb condenses both gases back into liquid, and fall back in the flask, with time the ethanol gains enough energy to over come the fractional coulomb (this happen before the water does this since ethanol has a LOWER boiling point) and pass through the condenser, changes into a liquid and is collected.


What are the steps in the process of obtaining pure petrol from crude oil?

The process of obtaining pure petrol from crude oil involves distillation in a refinery. Crude oil is heated in a distillation tower, separating it into different components based on their boiling points. Petrol, which has a lower boiling point, is collected as a separate fraction and further processed to remove impurities, resulting in pure petrol.


What steps involve the process of distillation?

In distillation, a liquid is heated to create vapor, which is then collected and cooled to condense back into a liquid. The condensed liquid is collected as the distillate. The process separates components based on differences in boiling points.


How do you use the word crude in a sentence?

"Charles take your hands out of your trousers, that is a very crude thing to do in public."The steps were crude, made from cinder blocks and boards.


How do you process oil?

It is heated through a furnace which is connected to a large tube. The different hydrocarbons in the Crude Oil will condense at different temeratures. The distilling tube is made so that there are different sections for the different temperatures that the crude oil will condense at. It then catches each different hydrocarbon.


What are the steps involved in variety reduction?

steps involved in the variety reduction?


What are steps involved in variety reduction?

steps involved in the variety reduction?