Name | Nguyen Minh Quan (Anthony) |
Roll Class | 11.5 |
Teacher | Mrs. Pham |
Date | 17/03/2010 |
???Petroleum??™ comes from the Greek word Petra, meaning ???rock??™, and the Latin word oleum, meaning ???oil??™. Petrol or ???gasoline??™ as it is called in North America is made from petroleum. Petroleum is the name given to the natural gas and crude oil that are drilled from underground or from under the sea floor. Petroleum can also be found in solid form as asphalt or tar. Most petroleum fuels are made from crude oil, the liquid part of petroleum. The gas part of petroleum, natural gas, has recently become a useful transport fuel, mainly for city buses. Petroleum is from the lithosphere, it was formed millions of years ago. The sticky black crude oil and the natural gas, drilled from under the ground or from under the sea floor, were formed from the bodies of ancient aquatic animals and plants. Crude oil, the liquid part of petroleum is not suitable for use as a fuel. It??™s too thick, and it has impurities that would clog up an engine. Before it can be used, crude oil must be refined. Refining means separating the crude oil into useful petroleum fuels and other petroleum products. Crude oil is a mixture of up to 330 different types of compounds called hydrocarbons- chemicals that contain hydrogen and carbon. Different hydrocarbons boil at different temperatures. Separating crude oil into its different hydrocarbons or ???fractions??™, depends on their different boiling temperatures. Petrol is a mixture of more than 200 kinds of hydrocarbons that boil below 1800C. Therefore Fractional Distillation is the best process to refine Petroleum. Fractional distillation is based on the principle that different fractions have different boiling points. As crude oil is heated, each fraction vaporises (turns into a gas or vapour) at its boiling point. As a vaporised fraction??™s temperature falls below its boiling point, it condenses (turns into a liquid)
Figure [ 1 ].fractionating tower
In fractional distillation, crude oil is pumped through pipes inside a boiler and heated to temperatures of 3430C. The resulting mixture of hot gases and liquids then passes into a vertical steel cylinder called a fractionating tower. A fractionating tower is divided into several different levels. The bottom level of the tower is hottest. Each level above the bottom is slightly cooler than the one below. As vaporise petroleum rise through the tower, fractions condense when the temperature drops below their boiling point. Heavy fuels oil condenses in the lower sections. Lighter fractions condense in the middle and upper sections. At each level, condensing fractions collect in trays and are drawn off by pipes along the sides of the tower. Some fractions do not cool enough to condense. They pass out of the top of the fractionating tower into a collection tank called the vapour recovery unit. Other fractions, which vaporise at temperatures higher than those in the furnace, remain as liquids or semisolids. These residues are recovered from the bottom of the tower and refined into such products as asphalt and lubricating oils. Fractional produced by fractional distillation are called straight-run products. Almost all must undergo conversion and chemical treatment before they can be used.
After all the process, the final products from petroleum are lubricating oil, paraffin wax, asphalt (at the highest temperature), Diesel oil, Kerosene, Gasoline, Naphtha, and Gases. All these products are very useful, especially Gasoline or Petrol. Petrol is an excellent fuel for transport. It has a very high energy content, which means that a small amount will drive a car for many kilometres. It is also easy to store. Diesel is used in the engines of most trucks, buses and ships, and some trains. Diesel fuel is a mixture of hydrocarbons that boil at temperatures between 1500C and 4000C. Diesel fuel is less refined than petrol so it is cheaper to produce than petrol. Kerosene is widely used to power jet-engine aircraft (jet fuel) and rockets, but is also commonly used as a heating fuel and for fire toys such as poi. Asphalt and lubricating oil remain on the bottom of the tower are still used for other purpose. Lubricating oil is used to reduce friction in a machine or engine, to transmit power, stop the risk of smoke and fire of objects, transfer heat.etc. And asphalt is used in road construction, where it is used as the glue of binder. The road surfacing is also called ???asphaltic concrete??™. The next one is naphtha. Naphtha is used as feedstock for producing high octane gasoline. It is also used in petrochemical industry for producing olefins in steam crackers and in the chemical industry for solvent application. The products made up from naphtha are lighter fluid, fuel for camp stoves, and some cleaning solvents.
Although nearly all petroleum can be refined into useful products, some fractions are much more valuable than others. The fact that from petroleum??™s fraction, gasoline is the most useful, but it just only makes up a small percentage of the straight-run products. Many less valuable fractions make up a higher percentage of crude oil. Therefore, scientists have developed several methods to convert less useful fractions into more valuable fractions to eliminate the wasting in the source. These methods are classified into three main groups: cracking processes, combining processes, reforming process. Conversion allows refiners to produce about half a barrel from a barrel of crude oil. Even petroleum is a useful fuel for transport industry.etc. On the other hand, it is considered the most damage reason cause the Air pollution and Global warming. Because the burning of petroleum fuels generates exhaust gases and particles that pollute the air.
The world??™s petroleum supply will not last forever. A limited amount of petroleum exists beneath the ground, and Petroleum companies cannot extract all of those are there. At current rates of consumption, the world recoverable crude oil reserves could run out in the mid ??“ 2000??™s. So Petroleum must not be wasted and it has to be used in the right purposes with the reasonable amount to reduce the pollution from its burning gases.
Mercer, I. 2003. Oils and the Environment. Franklins Watts. London.
2007. The World Book Encyclopaedia. World Book, Inc. USA
Date retrieved: 16/3/10
Date retrieved : 14/3/10