Petroleum. What is petroleum used for?
Petroleum is one of our most important fuels, and the petroleum industry is one of the largest in the world. The United States, Russia and Venezuela are the largest producers. Countries in the Middle East also produce large quantities, and they have the greatest known reserves of petroleum, too.
What is petroleum used for? When petroleum is released from impurity, its various chemical parts are separated and some become lubricants, some asphalt, some gasoline, and other interesting materials for rubber, plastics and other. Petroleum may be used for many things, for example: natural gas, crude oil, viscous etc. More details about it are possible to read below.
By refining crude petroleum in various ways, we obtain gasoline, or gas, for our automobiles; fuel oils for heating and producing power in ships, industry and diesel engines; kerosene (paraffin) for jet and rocket engines and for home heating; and all kinds of oil and greases to lubricate machinery. In addition, we obtain a host of useful chemicals, called petrochemicals, by processing petroleum.
Petroleum, often simply called oil, is a complicated mixture of substances called hydrocarbons, which are compounds of hydrogen and carbon only. It was formed millions of years ago from the remains of animals and plants, which lived in the seas.
The remains decayed and were buried by layer upon layer of mud
and sand, which turned into rock. Heat, pressure and decay changed
the remains into drops of oil and also natural gas.
In a fault trap, oil has accumulated behind a wedge of non-porous rock which has slipped down into the oil-bearing rock layer. Oil may also be trapped in the top of a rock fold or where an oil-bearing layer tapers to a wedge. It may also collect on top of huge domes of salt thrust up from deep underground.
Prospecting, or looking for petroleum, is a skilled job and petroleum engineering training is the important work which should be spent with all workers. Oil geologists do not look for oil directly but they try to find traps in which oil may lie. They use a variety of instruments to help them, including magnetometers and gravity meters. But their most useful instrument is the seismograph. The oil prospector sets off an explosion and records the vibrations at various distances by seismograph. This will tell him the shape and depth of underlying rocks.
When the oilmen decide to drill for oil, they set up a tall derrick to hoist equipment into the drill hole. Most oil wells are bored by rotary drilling. The drill consists of lengths of pipe joined together, with a sharp cutting bit at the bottom. A steel turntable on the derrick floor grips and turns the pipe. A liquid drilling mud is pumped through the pipe to cool the bit and to flush out rock cuttings. The well is lined with casing as it is drilled.
When oil is found, it usually flows to the surface naturally. Water below, or compressed gas above, pushes the oil out of the well. The crude oil is taken from the wells to oil refineries, often in different countries, to be processed. Pipelines and tankers are means of transporting the oil.
What is petroleum used for? At the refinery, the first step in processing is distillation, or fractionating, which separates the crude oil into its constituents, or fractions. The oil is heated in a furnace and passed into a fractionating column. The fractions separate into different trays in the column according to their boiling points. Gasoline and light oils condense at the top, heavy fuel oils at the bottom.
The heavy oils can be cracked, or broken down, into useful products such as gasoline. In thermal cracking, they are broken down by heat and pressure. In catalytic cracking, they are heated with a catalyst - a substance which helps the reaction but does not itself change.
The gaseous fractions from the column and from cracking can be
'built up' into gasoline. Polymerization and alkylation are
processes in which the small gas molecules combine to form larger
ones. These gases are also used as a starting point to make
petrochemicals. They are converted into plastics and synthetic
rubber, solvents for paints, antifreeze mixtures, and man-made
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