Crude Density Oil
Crude Density Oil
Petroleum (L. petroleum , from Greek πετρέλαιον , lit. "rock oil" ) or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights, and other organic compounds, that are found in geologic formations beneath the earth's surface.
The term "petroleum" was first used in the treatise De Natura Fossilium , published in 1546 by the German mineralogist Georg Bauer, also known as Georgius Agricola.
Composition
In its strictest sense, petroleum includes only crude oil, but in common usage it includes both crude oil and natural gas. Both crude oil and natural gas are predominantly a mixture of hydrocarbons. Under surface pressure and temperature conditions, the lighter hydrocarbons methane, ethane, propane and butane occur as gases, while the heavier ones from pentane and up are in the form of liquids or solids. However, in the underground oil reservoir the proportion which is gas or liquid varies depending on the subsurface conditions, and on the phase diagram of the petroleum mixture.
An oil well produces predominantly crude oil, with some natural gas dissolved in it. Because the pressure is lower at the surface than underground, some of the gas will come out of solution and be recovered (or burned) as associated gas or solution gas . A gas well produces predominately natural gas. However, because the underground temperature and pressure are higher than at the surface, the gas may contain heavier hydrocarbons such as pentane, hexane, and heptane in the gaseous state. Under surface conditions these will condense out of the gas and form natural gas condensate, often shortened to condensate . Condensate resembles gasoline in appearance and is similar in composition to some volatile light crude oils.
The proportion of hydrocarbons in the petroleum mixture is highly variable between different oil fields and ranges from as much as 97% by weight in the lighter oils to as little as 50% in the heavier oils and bitumens.
The hydrocarbons in crude oil are mostly alkanes, cycloalkanes and various aromatic hydrocarbons while the other organic compounds contain nitrogen, oxygen and sulfur, and trace amounts of metals such as iron, nickel, copper and vanadium. The exact molecular composition varies widely from formation to formation but the proportion of chemical elements vary over fairly narrow limits as follows:
Four different types of hydrocarbon molecules appear in crude oil. The relative percentage of each varies from oil to oil, determining the properties of each oil.
Crude oil varies greatly in appearance depending on its composition. It is usually black or dark brown (although it may be yellowish or even greenish). In the reservoir it is usually found in association with natural gas, which being lighter forms a gas cap over the petroleum, and saline water which, being heavier than most forms of crude oil, generally sinks beneath it. Crude oil may also be found in semi-solid form mixed with sand and water, as in the Athabasca oil sands in Canada, where it is usually referred to as crude bitumen. In Canada, bitumen is considered a sticky, tar-like form of crude oil which is so thick and heavy that it must be heated or diluted before it will flow. Venezuela also has large amounts of oil in the Orinoco oil sands, although the hydrocarbons trapped in them are more fluid than in Canada and are usually called extra heavy oil. These oil sands resources are called unconventional oil to distinguish them from oil which can be extracted using traditional oil well methods. Between them, Canada and Venezuela contain an estimated 3.6 trillion barrels (570
×
10
^
9
m
3
) of bitumen and extra-heavy oil, about twice the volume of the world's reserves of conventional oil.
Petroleum is used mostly, by volume, for producing fuel oil and gasoline (petrol), both important "primary energy" sources. 84% by volume of the hydrocarbons present in petroleum is converted into energy-rich fuels (petroleum-based fuels), including gasoline, diesel, jet, heating, and other fuel oils, and liquefied petroleum gas. The lighter grades of crude oil produce the best yields of these products, but as the world's reserves of light and medium oil are depleted, oil refineries are increasingly having to process heavy oil and bitumen, and use more complex and expensive methods to produce the products required. Because heavier crude oils have too much carbon and not enough hydrogen, these processes generally involve removing carbon from or adding hydrogen to the molecules, and using fluid catalytic cracking to convert the longer, more complex molecules in the oil to the shorter, simpler ones in the fuels.
Due to its high energy density, easy transportability and relative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics; the 16% not used for energy production is converted into these other materials. Petroleum is found in porous rock formations in the upper strata of some areas of the Earth's crust. There is also petroleum in oil sands (tar sands). Known reserves of petroleum are typically estimated at around 190 km
3
(1.2 trillion (short scale) barrels) without oil sands, or 595 km
3
(3.74 trillion barrels) with oil sands. Consumption is currently around 84 million barrels (13.4
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10
^
6
m
3
) per day, or 4.9 km
3
per year.
Chemistry
Petroleum is a mixture of a very large number of different hydrocarbons; the most commonly found molecules are alkanes (linear or branched), cycloalkanes, aromatic hydrocarbons, or more complicated chemicals like asphaltenes. Each petroleum variety has a unique mix of molecules, which define its physical and chemical properties, like color and viscosity.
The alkanes , also known as paraffins , are saturated hydrocarbons with straight or branched chains which contain only carbon and hydrogen and have the general formula C n H 2n+2 They generally have from 5 to 40 carbon atoms per molecule, although trace amounts of shorter or longer molecules may be present in the mixture.
The alkanes from pentane (C 5 H 12 ) to octane (C 8 H 18 ) are refined into gasoline (petrol), the ones from nonane (C 9 H 20 ) to hexadecane (C 16 H 34 ) into diesel fuel and kerosene (primary component of many types of jet fuel), and the ones from hexadecane upwards into fuel oil and lubricating oil. At the heavier end of the range, paraffin wax is an alkane with approximately 25 carbon atoms, while asphalt has 35 and up, although these are usually cracked by modern refineries into more valuable products. The shortest molecules, those with four or fewer carbon atoms, are in a gaseous state at room temperature. They are the petroleum gases. Depending on demand and the cost of recovery, these gases are either flared off, sold as liquified petroleum gas under pressure, or used to power the refinery's own burners. During the winter, Butane (C 4 H 10 ), is blended into the gasoline pool at high rates, because butane's high vapor pressure assists with cold starts. Liquified under pressure slightly above atmospheric, it is best known for powering cigarette lighters, but it is also a main fuel source for many developing countries. Propane can be liquified under modest pressure, and is consumed for just about every application relying on petroleum for energy, from cooking to heating to transportation.
The cycloalkanes , also known as naphthenes , are saturated hydrocarbons which have one or more carbon rings to which hydrogen atoms are attached according to the formula C n H 2n . Cycloalkanes have similar properties to alkanes but have higher boiling points.
The aromatic hydrocarbons are unsaturated hydrocarbons which have one or more planar six-carbon rings called benzene rings, to which hydrogen atoms are attached with the formula C n H n . They tend to burn with a sooty flame, and many have a sweet aroma. Some are carcinogenic.
These different molecules are separated by fractional distillation at an oil refinery to produce gasoline, jet fuel, kerosene, and other hydrocarbons. For example 2,2,4-trimethylpentane (isooctane), widely used in gasoline, has a chemical formula of C 8 H 18 and it reacts with oxygen exothermically:
The amount of various molecules in an oil sample can be determined in laboratory. The molecules are typically extracted in a solvent, then separated in a gas chromatograph, and finally determined with a suitable detector, such as a flame ionization detector or a mass spectrometer.
Incomplete combustion of petroleum or gasoline results in production of toxic byproducts. Too l
What is Crude Oil?
Crude oil is considered light if the level of hydrocarbons relative to organics and metals is high, making its density low, and it is considered heavy if the level of hydrocarbons ...
Crude oil blending
The crude oil feed-stocks used for blending often vary in quality and for this reason crude oil blenders normally use viscosity | or density trim | control systems.
crude oil - OnlineConversion Forums
Also crude oil has a range of densities. There is certainly crude in the range of density you used, but you need to know the density of a particular lot.
Light crude oil - Wikipedia, the free encyclopedia
Light crude oil is liquid petroleum that has a low density and flows freely at room temperature. [1] It has a low viscosity, low specific gravity and high API gravity due to the presence ...
Heavy crude oil - Wikipedia, the free encyclopedia
Heavy crude oil or extra heavy crude oil is any type of crude oil which does not flow easily. It is referred to as "heavy" because its density or specific gravity is higher than ...
WikiAnswers - What is the density of crude oil
Physics question: What is the density of crude oil? The density of crude oil is between 0,75-1,05g/cm3. Anderson Aggrey
crude oil@Everything2.com
The carbon atom number determines the oil's "weight" or density. Gases such as natural gas ... Someday we will all be crude oil and diamonds: Oil depletion: Oil drilling platform
crude oil [Archive] - OnlineConversion Forums
Also crude oil has a range of densities. There is certainly crude in the range of density you used, but you need to know the density of a particular lot.
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Key Phrase page for crude oil density: Books containing the phrase crude oil density
Live Crude Oil Density Characterisation
In view of the major economic impact of any errors in determination of crude oil volumes, there is an urgent requirement to check the validity of generic expansion coefficients ...
