Petroleum

Petroleum (L. petroleum, from Greek: petra (rock) + Latin: oleum (oil)) or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling. This latter stage comes after the studies of structural geology (at the reservoir scale), sedimentary basin analysis, reservoir characterization (mainly in terms of porosity and permeable structures). It is refined and separated, most easily by boiling point, into a large number of consumer products, from petrol and kerosene to asphalt and chemical  reagents used to make plastics  and pharmaceuticals. Petroleum is used in manufacturing a wide variety of materials.

FORMED AND EXPLORATION

The crude oil we use today was formed millions of years ago. Oil is formed deep under the surface. Petroleum is formed from organic materials. This organic material comes from the remains of dead organisms. The organic material becomes a part of layers of sedimentary rocks. More layers form on the top of these layers and the organic material changes into petroleum, and is contained into a source rock. This causes the petroleum to turn into oil.

petroleum are often found on the seabed near the loose beach so constructed offshore oil platforms and the mainland not far from the beach. This is due the movement of the earth's crust that cause a shift in the lining rocks, such as earthquakes and volcanic eruptions. There are illustration of how the ptroleum formed.

To determine the source of the petroleum needed knowledge geology and experience. This work is a duty and responsibility responsible mining and geological engineers.

The first stage of oil exploration is to find clues in the earth's surface like the folds of rock. The folds was due to pressure oil and gas that seeps into the rocks porous so that oil can rise to the surface, but not reaching the earth's surface because it was blocked by layers of other rocks. Based on observations and surface structure clues earth, the next area investigated using the beam wave seismic. The radiation of seismic waves are used to determine rock structures in the skin layer of the earth.

Seismic waves are created using a small explosion. Explosion This will generate a wave and sends it to the depth certain. If there is a bubbling rock structures (anti Cline), wave will be reflected back. These reflections can be detected by sensor so that it can be seen to accurately position the petroleum To remove the oil and natural gas from rock layers layer of earth drilling required to reach the bottom layer of rock containing petroleum. Depth can reach hundreds of meters. Once drilled,  the oil initially will  radiateits own due layers of earth pressure is high, but the more upward pressure is increasing weak so that  the required pressure from the outside. This is done by using water or air pump until oil can pumped out. Transportation of crude oil can be done with using tankers.

COMPOSITION OF CRUDE OIL

Crude oil is a very complex mixture, which is about 50-95% are hydrocarbons, especially the alkanes with molecular weight above 100's; cycloalkanes; aromatic compounds; Compound micro, such as organic acids, and inorganic elements such as sulfur. Hydrocarbons in crude oil consists of saturated hydrocarbons, aliphatic, and alicyclic. Most of the components of crude oil is saturated hydrocarbons, ie alkanes and cycloalkanes.

1. Alkane

Alkane compounds contained in any oil that has a chain carbon straight as n-butane  and n heptane, there also have carbon chain branch such as 2,2,4 trimetilpentan (isooktana). Alkane compound structural formula is:

In the petroleum compounds are most commonly found compounds straight chain  hydrocarbons.

2.Cycloalkanes 

Cycloalkanes are found in petroleum for example metilsiklopentana and  etilsikloheksana with the following structural formula is:

3. Aromatic hydrocarbons

The simplest aromatic hydrocarbon compounds found in petroleum is benzene  (C6H6) and metilbenzena with the structural formula is: 

4. Other compounds

Composition of petroleum out varies from area to area. There  are saturated hydrocarbons, unsaturated  hydrocarbons, sulfur and oxygen compounds, and organ metallic. The number of content or levels of these compounds to determine the quality of petroleum. The results of  refining   the oil and gas in Indonesia has better quality than those produced byother countries.

PROCES TO MAKE PETROLEUM CAN BE USES

Crude oil is a very complex mixture of the  need to be further processed to be used.

1. Distillation

Crude oil needs to be processed in refineries through stratified by fractionating  distillation techniques. The basic principle of distillation boiling point rise is the difference in between crude oil fractions. Hydrocarbons which has the lowest boiling point will separate first, followed by a hydrocarbon having a boiling point over high. So, gradually, hydrocarbons can be separated from mixture of crude oil.

The first fraction of crude oil out of the refinery is hydrocarbon compounds with low molecular mass, less than 70 sma. This fraction is packaged in a pressurized tube until melted. Outcome processing in this fraction is known as LPG (liquid  petroleum gas). After all factions teruapkan, which came out the next fraction is gasoline fraction. Temperature is applied to remove this fraction ranged between 40  -200 ° C.

At these temperatures, hydrocarbons ranging from pentane to octane removed from the distillation (see the boiling point of pentane to octane).

At room temperature, form of this fraction was a colorless liquid until slightly yellow and volatile. And so on until all the fractions can be separated incrementally based on differences in their boiling points. The results of the fractionation leaving a residue called black-colored asphalt.
2. Cracking

To meet the needs of a particular product, hydrocarbon long-chain can be broken down into shorter through the process cracking (cracking). Conversely, short chain hydrocarbons can be combined into a longer chain (reforming). To increase the gasoline fraction can be done in a way break down long chain hydrocarbons into fractions (C5-C9) through thermal cracking. Cracking process is carried out at a temperature of 500 ° C. and a pressure of 25 atm. Saturated straightchain hydrocarbons such as kerosene (C12H26) can be crack into  two shorter fragments there are hexane  (C6H14) and hexene (C6H12).

    

The presence of hexene (alkenes) from the thermal cracking can be increase the octane number of 10 units. However, the product of the process This cracking is generally less stable when stored for a long time. Therefore the thermal cracking  products are generally less stable then the thermal cracking technique is replaced by catalytic cracking conducted using a catalyst at high temperature and pressure.

Catalytic cracking,  for example long-chain alkanes is reacted with mixture of silicon (SiO2) and alumina (Al2O3), plus a hydrogen gas or a specific catalyst.
In reforming, small molecules are combined into molecules is greater. This is done to improve petrol products. For example, butane and propane are reacted to form heptane. Reaction equation:

3. Reforming

Small molecules are combined into greater molecules. This is done to improve
petrol products, change shape/structure of  gasoline’s molecule from bad quality  (straight carbon chain) to good quality (branch carbon chain). For  example, butane and propane are reacted to form heptane. Reaction equation:

4.  Octane number

Octane number is the number ratio of value gasoline knock and value hydrocarbon mixture standar knock The function is for distrution burning of gasoline to avoid knocking a result of the shock wave when burning gasoline straight chain are uneven in high pressure engine.

Three methode for measure octane number:

1)      measurements at  velocity and high temperatures, the results are expressed as the engine octane numbers;

2)      measurements on medium speed, the result is called the research octane number;

3)      pure hydrocarbon measurement,  called octane numbers road index.

Because 2,2,4trimetilpentana has the highest  octane  number (100) and n-heptane lowest(0) then the mixture of two compounds used as standards to measure the octane number. Octane  number for mixture of 87%  isooktana and 13%  n-heptane is set at 87 units.

ANOTHER PRODUCT FROM PETROLEUM 

ENVIROMENT IMPACT

1.  Hydrocarbon (CnHx)

                It is formed by the impaired combustion that cause global warming. Some hydrocarbon is stink dan the other role in photochemical. Some aromatics and its derivative causes cancer, while olefins in high concentration can inhibit plant growth. In the air, hydrocarbon make the ozon concentration increase, form the organic compound likes peroxyacetyl nitrate (PAN), peroxybenzoil nitrate (PBzN) and nitric acid. That compound together then form fog called photochemical fog (causes the fog formed from photochemial reaction).

2. Carbon monoxide

It is caused by the impaired combustion of gasoline. It is toxic so that causes headache. if in the air contain much CO gas, hemoglobin will  bind CO gas than O2 gas. So people who breath the gas continued will be die.

                The symptomps of being poisened by CO:

                Step 1: sick headache and weak.

                Step 2: hard to breath, heart attack, dan collaps.

                Step 3: death and lips look pale.

3.  Nitrogenoxide

                It can causes acid rain and effect the engine to heat-up quickly.

4. Soft lead particles

               soft lead particles come from incomplate combustion in vehicle engine. It causes brain damage, especially for kids.

5. Smoke

                It is formed by carbon particles which are not burned. These particles can cause lungs inflammation.

6. Sulphuric oxide

                SO2 derived cause of gasoline still contain sulfur, it can form be SO3. in dampness its very corosive. Over 0.20 ppm for 24 hours in the air its causes respiratory system disorders, cancer and acute bronchitis. That occur becase SO2 breathed react with water in respiratory sistem form sulfit acid. The reaction is:

7. Greenhouse Effect       

When the fossil fuels burned in cars and a power, CO2 gas is released as residual gas is removed. Actually there is a gas naturally in the earth's atmosphere to trap solar heat that the earth is becoming warm. However, the presence of CO2 in the atmosphere become redundant due to combustion engines and power generation, so that the trapped solar heat more and more. As a result, there was a significant increase in temperature in earth. That is why the earth is getting warmer. When the earth is hotter, weather changes are striking.  Some countries will be more moist, and others are more dry.

8. Acid Rain

Combustion of coal on power plants produce waste gas which combines with water in the atmosphere to form sulfuric acid clouds and nitric acid. The clouds come down as acid rain. acid rain causes damage to the leaves of plants and fish kills in freshwater lakes.