Understanding Oil: From Exploration to Refining and Fuel Properties
1. What is Oil?
Oil is a viscous liquid, ranging in color from yellow to dark brown to black, sometimes with green reflections. It has a characteristic odor and floats in water. Oil is primarily composed of hydrogen and carbon, with smaller amounts of oxygen, sulfur, nitrogen, and metals like vanadium, nickel, aluminum, iron, copper, sodium, calcium, and uranium.
2. What is the Composition of Oil?
Oil is a complex mixture of hydrocarbons, including:
- Aromatic Compounds: n-C5-C44 alkanes, branched alkanes, cycloalkanes, saturated simple rings, and condensed rings.
- Asphaltenes: Containing compounds with oxygen, nitrogen, and sulfur.
3. Main Derivatives from Oil Distillation
Fuel Derivatives:
- 93 Octane Gasoline
- 95 Octane Gasoline
- 97 Octane Gasoline
- 100/130 Aviation Gasoline
- Domestic Kerosene
Petrochemical Derivatives:
- Ethylene
- Polyethylene
- Low Density Polyethylene
- Propylene
- Polypropylene
- High Density Polypropylene
Industrial Derivatives:
- White Petrol
- Mineral Turpentine
- Industrial Xylene
- Solvent Mining
- Solvent 4
- Solvent 10
4. What is a Refinery?
A refinery is an industrial facility that transforms crude oil into usable products through various processes, including:
- Cleaning with water to remove impurities
- Desalting for separation by boiling points (distillation)
- Refining through conversion reactions to change molecular structures
- Mixing components to achieve desired commercial properties
Process Flow: RAW -> DESAL -> REFINED -> REFORMED -> MIXED
5. Stages of Oil Refining
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6. What is Prospecting?
Prospecting involves finding oil underground. Geologists search for sedimentary basins containing organic-rich shales that have been buried long enough for oil to form.
7. Surface Prospecting Methods for Oil Exploration
Gravity Method:
Detects gravity anomalies caused by density variations in the subsoil, indicating potential oil deposits.
Magnetic Prospecting:
Identifies anomalies in the Earth’s magnetic field caused by the presence of ferromagnetic, diamagnetic, and paramagnetic minerals, which can be associated with oil reservoirs.
Seismographic Prospecting:
Uses explosions or vibrations to create seismic waves that travel through the Earth and are reflected back to the surface. Analyzing these waves helps map underground geological structures and identify potential oil traps.
8. Procedures for Drilling and Extracting Oil
Percussion Drilling:
A heavy cutting tool is repeatedly dropped into the ground to break up the rock and create a borehole.
Rotary Drilling:
A rotating drill bit cuts through the rock, and new sections of pipe are added as the borehole deepens.
9. Oil Extraction Methods
- Primary Extraction: Utilizes natural reservoir pressure or pumping to extract oil.
- Secondary Extraction: Involves injecting water or gas into the reservoir to increase pressure and displace oil towards production wells.
Secondary Extraction by Gas Injection or Water Circulation: Used when natural pressure is insufficient, injecting water or gas to force oil out.
10. API Gravity Classification of Crude Oil
The oil industry classifies crude oil based on its API gravity, a measure of its density compared to water. Lighter oils have higher API gravity.
11. Characteristics of Common Fuels
Naphtha:
Highly volatile and flammable, used primarily as a fuel for combustion engines. Calorific value: 11,000 cal/kg.
Kerosene:
Less volatile and flammable than naphtha, used in heating and jet engines. Calorific value: 10,500 cal/kg.
Gas Oil:
Heavy and less volatile than kerosene, used in heating and industrial furnaces. Calorific value: 10,250 cal/kg.
Diesel Oil:
Heavier than gas oil, burns more slowly, used in diesel engines. Calorific value: 11,000 cal/kg.
Fuel Oil:
Heaviest and least volatile, burns with difficulty. Calorific value: 10,000 cal/kg.
12. Classification of Reformation Processes
- Simple Distillation: Separates petroleum products based on boiling points without changing their molecular structure.
- Thermal Cracking: Breaks down long hydrocarbon chains into smaller molecules, often producing gasoline components.
- Alkylation and Catalytic Cracking: Use catalysts to rearrange and combine molecules, improving the octane rating of gasoline.
13. Basic Concepts of Fuel Properties
Oxidizer:
A substance that provides oxygen or another element needed for combustion.
Combustible:
A substance that can ignite and burn.
Combustion:
Rapid oxidation of a substance with the evolution of heat and usually light, gas, or smoke.
Detonation:
An uncontrolled explosion in a combustion chamber, causing damage to the engine.
Deflagration:
A rapid combustion that propagates through a gas or along the surface of an explosive material at subsonic speeds.
Flash Point:
The lowest temperature at which a liquid releases enough vapor to ignite in the presence of an ignition source.
Ignition Temperature (Autoignition Temperature):
The minimum temperature at which a substance will spontaneously ignite without an external ignition source.
Pour Point:
The lowest temperature at which a liquid can flow under specific conditions.
Dew Point:
The temperature at which water vapor in the air begins to condense.
Solidification Point:
The temperature at which a liquid changes into a solid state.
Adiabatic Compression:
Compression of a gas without any heat exchange with the surroundings.
Boiling Point:
The temperature at which a liquid changes into a vapor.
Volatilization:
The process of a liquid changing into a vapor.
Imperfect Combustion:
Combustion where not all of the fuel is completely oxidized.
Complete Combustion:
Combustion where all of the fuel is completely oxidized.
Octane Index:
A measure of a fuel’s resistance to knocking or detonation in a spark-ignition engine.
Cetane Index:
A measure of a fuel’s ignition quality in a diesel engine.
Density:
The mass of a substance per unit volume.
Turbidity Point (Cloud Point):
The temperature at which wax crystals begin to form in a fuel, causing it to become cloudy.
Reid Vapor Pressure (RVP):
A measure of the volatility of a liquid fuel.
Sulfur Content:
The amount of sulfur present in a fuel.
Viscosity:
A measure of a fluid’s resistance to flow.
Water and Sediment Content:
The amount of water and sediment present in a fuel.
Sublimation:
The process of a solid changing directly into a gas without passing through the liquid state.
14. Definitions of Basic Terms
Chemical Process:
A set of operations that transform raw materials into desired products through chemical or physical changes.
Atom:
The smallest unit of an element that retains the chemical properties of that element.
Molecule:
Two or more atoms held together by chemical bonds.
Analysis:
The process of breaking down a complex substance into its constituent parts.
Synthesis:
The process of combining simpler substances to form a more complex substance.
Oxidation:
A chemical reaction involving the loss of electrons or an increase in oxidation state.
Reduction:
A chemical reaction involving the gain of electrons or a decrease in oxidation state.
Fundamental Physical Concepts:
Basic principles that govern the behavior of matter and energy.
Physical Phenomena:
Observable events that occur in the natural world.
States of Matter:
Solid, liquid, and gas.
Thermal Conductivity:
The ability of a material to transfer heat.
Mass:
A measure of the amount of matter in an object.
Density:
Mass per unit volume.
Force:
An influence that can change the motion of an object.
Cohesion:
The attraction between molecules of the same substance.