Tray In The Fractionating Column example essay topic

EXTRACTION OF USEFUL PRODUCTS FROM PETROLEUM Petroleum or crude oil contains many useful liquids that can be extracted from it such as kerosene, diesel, petrol and other things. The various components of crude oil have different sizes, weights and boiling points; so, these components are separated according to differences in boiling point. The process used for separating petroleum is called fractional distillation Distillation is carried out in a fractionating tower. In here one can find a number of horizontal trays at different intervals along the height of the column. Petroleum is heated in a furnace and is passed into the lower part of the fractionating column.

The column is very hot at the base, but its temperature gradually drops the higher up the column. It is for this reason that each tray is cooler than the tray below it. There is a hole in each tray in the fractionating column. These are called bubble caps.

There is some metal covering this hole, which prevents gases being forced up to the next tray without a liquid being condensed in the tray below it. When liquid is condensed gases can flow into the next tray, through small holes in the bubble cap. The majority of the components in the oil are already in a gaseous state when they go through the fractionating column. The components rise up the column until they reach the tray to which the temperature the slightly below its boiling point.

It is here where the components of petroleum are separated when they condense and become different liquids. The substance with the lowest boiling point will condense at the highest point in the column; substances with higher boiling points will condense lower in the column the fractions are then separated and different liquids obtained. Pipes draw out the liquids from their particular trays. This is a continuous process as hotter crude oil keeps flowing into the base of the column. The most volatile fractions.

(Those with lowest boiling point) come out of the top of the column and are gases, as these have very low molecular masses (e.g. Methane). The heaviest compounds fall to the bottom of the column. These compounds have the highest molecular masses and are the least volatile. There is residue left over and this flows out of the bottom of the column.

The collected liquid fractions may: pass to condensers, which cool them further, and then go to storage tanks or go to other areas for further chemical processing After the fractions have been treated, they are cooled and then blended together to make various products, such as: . Gasoline of various grades, with or without additives. Lubricating oils of various weights and grades (e.g. 10 W-40, 5 W-30). Kerosene of various grades. Jet fuel. Diesel fuel.

Heating oil. Chemicals of various grades for making plastics and other polymers. Bitumen. Fuel oil. Aviation oil. Gases e.g. LPG Each fraction has its own use.

In the case of crude oil no fraction is wasted. Here are their various uses. Fraction Boiling Point (Celsius) Carbon Atoms per molecule Uses Gases: Below 40 C 1-4 Domestic fuel (Bottled gas), motor fuel (LPG) Petrol: 40 C-160 C 4-11 Petrol, Kerosene: 160 C-250 C 12-16 Mainly for jet fuel Other oils: 250 C-350 C 17-25 Diesel oil, heating oil, Residue & lubricants: Above 350 C Above 25 Lubricants, waxes, greases, for road surfacing, Safety Issues There are many safety issues involved in the distillation of petroleum. Products obtained from petrol are highly flammable. Even though the fractionating tower may be closed, it could still provide a source of ignition, and the potential for a fire or a explosive chemical reaction to occur should a leak take place. Before the oil is even put into the fractionating tower, the fractions are treated to remove contaminants such as organic compounds containing sulfur, nitrogen, oxygen, water, dissolved metals and various salts.

Passing each of the fractions through the following processes usually does treating... A column of sulfuric acid - gets rid of unsaturated hydrocarbons (those with carbon-carbon double-bonds), nitrogen and oxygen compounds... An absorption column filled with drying agents, removes water... Sulfur treatment and hydrogen sulfide scrubbers any other sulfur compounds. If the fractionating tower contains some water in suspension this should be separated during the start of the distillation process.

If it isn't separated, this water will then settle in the bottom of the tower. The water will then be heated and can create an explosion as the water vapour can react with the oil in the rest of the fractional tower. This is why water is removed from the fractions before distillation. Other compounds must be removed from the fractions as the heat in the tower may produce some unwanted gases and this could also cause violent reactions in the tower spoiling the entire distillation process. If unsaturated hydrocarbons are present in petroleum, the fractions may not function properly as these hydrocarbons could have different boiling points altogether, the extraction of the various liquids and mixtures with no fixed boiling points will contaminate the final products. There are several other safety practices taken out in the oil refinery.

Fire drills are regular events in the oil refinery, to prepare for any fire outbreak. There are fire extinguishers everywhere in the oil refinery and many different chemicals and instruments to combat if anything were to arise. A large petroleum company may contain as many as one hundred safety coordinators. They work in a very hazardous environment and do whatever possible to prevent any person from being hurt.

Training programs are also put in place on a variety of subjects such as in the handling of the crude oil, the measurements of crude oil bring poured into the tower, and the operation of electrical equipment involve din the fractional distillation of petroleum. Some companies put in regularly new equipment just to be safe. This equipment is usually certified before put into production to ensure that the right materials are used for the job. Many everyday chemicals such as kitchen cleaners and after-shave are usually banned, as they can be a fire hazard within the refinery. Overall, the all refinery does good job in separating the components useful products from petroleum. These products are very influential to our society, without them our means of driving, flying and means of keeping warm would unattainable.

Many reliable safety practices are put into followed to ensure the safety of the oil refinery workers and to make certain products will not be contaminated. For these value resources sometimes referred to as 'liquid gold', which mean so much, the oil refinery is taking good responsibility of the oil and its colleagues.

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