Petro

INTRODUCTION TO PETROLEUM REFINING AND PETROCHEMICAL INDUSTRIES

• Dr. Ozge YUKSEL ORHAN
• Hacettepe University Chemical Engineering Department
• February, 2025

TÜRKİYE PETROL RAFİNERİLERİ HARİTASI (TURKEY PETROLEUM REFINERY MAP)

• Lists various cities and regions including Istanbul, Izmit, Ankara, and Adana.
• Identifies locations of petroleum refineries such as İzmit Rafinerisi, Aliağa Star Rafinerisi, Kırıkkale Rafinerisi, and Batman Rafinerisi.
• Shows petroleum pipelines including:
  • Irak-Türkiye Petrol Boru Hattı (Iraq-Turkey Oil Pipeline) - 1
  • Baku - Tiflis - Ceyhan Petrol Boru Hattı (Baku-Tbilisi-Ceyhan Oil Pipeline) - 2
  • Ceyhan Kırıkkale Petrol Boru Hattı (Ceyhan-Kirikkale Oil Pipeline) - 3
  • Batman - Dörtyol Petrol Boru Hattı (Batman-Dortyol Oil Pipeline) - 4

PETROLEUM: A VITAL NATURAL RESOURCE

• Petroleum is a natural fossil fuel, a liquid hydrocarbon mixture extracted from rock formations beneath the Earth's crust.
• The word has Latin origins, derived from "Petra" (rock) and "Oleum" (oil).
• Historically referred to as "rock oil."

WHAT IS CRUDE OIL?

• Crude oil is a natural hydrocarbon mixture stored within porous rocks, formed over millions of years through the chemical transformation of organic materials deep within the Earth's crust.
• The term "crude" indicates that the oil is in its unrefined, raw form, serving as a primary raw material.
• Crude oil cannot be used directly; instead, it undergoes distillation and separation processes in refineries to produce essential products such as gasoline, diesel, kerosene, and plastics, which are widely used in daily life.
• Properties of Crude Oil
  • Physical Appearance: Typically black or dark brown in color; its consistency can range from fluid to viscous, depending on its composition.
  • Chemical Composition: Mainly consists of hydrocarbons, composed of carbon (C) and hydrogen (H) atoms. It may also contain small amounts of sulfur, nitrogen, oxygen, and metals.
  • Flammability: Has a high energy content, making it widely used as a fuel source.

NATURAL GAS

• Natural gas is a fossil energy source formed through geological processes over millions of years deep within the Earth's crust.
• Its primary component is methane ($CH₄$), a molecule consisting of one carbon and four hydrogen atoms.
• Composition of Natural Gas:
  • Methane ($CH₄$): The main component of natural gas.
  • Natural Gas Liquids (NGLs): Contains hydrocarbon gas liquids.
  • Other Gases: May include small amounts of carbon dioxide ($CO₂$), water vapor ($H₂O$), and nitrogen ($N₂$).
• Uses of Natural Gas:
  • As a Fuel: Used in electricity generation, heating, and industrial applications.
  • In Chemical and Industrial Sectors: Essential for the production of plastics, fertilizers, paints, and various chemicals.
• Natural gas is a widely used energy source due to its clean-burning nature and high energy efficiency.

PETROLEUM and NATURAL GAS FORMATION

• Tiny marine plants and animals died and were buried on the ocean floor.
• Over time, the marine plants and animals were covered by layers of silt and sand.
• Over millions of years, the remains were buried deeper and deeper.
• The enormous heat and pressure turned the remains into oil and natural gas.
• Today, we drill down through layers of sand, silt, and rock to reach the rock formations that contain oil and natural gas deposits.

FORMATION of PETROLEUM and NATURAL GAS

• Millions of years ago
• Thousands of years ago
• At present

WHAT IS KEROGEN?

• Kerogen is an insoluble organic material found within rocks and serves as the primary source for the formation of petroleum and natural gas.
• It mainly consists of remnants of plant and animal organisms that were buried and transformed over millions of years.
• Under high temperature and pressure, kerogen undergoes thermal decomposition, breaking down into hydrocarbons such as crude oil and natural gas.
• The type and composition of kerogen determine the quality and type of hydrocarbons produced.
• How is Kerogen Formed?
  • Accumulation of Organic Matter
    • In aquatic environments like seas and lakes, plankton, plants, and animal remains settle and accumulate in sediment layers.
  • Diagenesis (Early Transformation)
    • As organic material is buried under sediment, low temperature and pressure conditions cause initial chemical and physical changes, leading to kerogen formation.
  • Catagenesis (Maturation Process)
    • With increasing temperature and pressure, kerogen undergoes pyrolysis, breaking down into petroleum and natural gas.
  • Metagenesis (Late Transformation)
    • At even higher temperatures, petroleum molecules continue to crack, leading to increased natural gas production.
  • This gradual transformation process is essential for the formation of fossil fuels over millions of years.

TYPES OF KEROGEN AND THEIR PETROLEUM POTENTIAL

• Type I and Type II kerogens are the most valuable for petroleum production.
• Type III kerogen primarily produces natural gas.
• Type IV kerogen has low economic potential for hydrocarbon production.

WHY IS KEROGEN IMPORTANT?

• Primary raw material for petroleum and natural gas.
• Fundamental component of fossil fuel formation.
• Analyzed to determine the petroleum potential of rocks.

CATAGENESIS PROCESS

• Catagenesis is the stage in which kerogen undergoes thermal decomposition due to increased temperature and pressure, leading to the formation of petroleum and natural gas.
• Stages of Catagenesis:
  • Low-Temperature Transformation:
    • Kerogen starts breaking down into liquid hydrocarbons.
    • Mainly results in the formation of crude oil.
  • Peak Oil Generation:
    • Occurs at temperatures between 60–150°C.
    • The highest amount of oil is produced in this phase.
  • Gas Formation (Metagenesis Transition):
    • At higher temperatures (above 150°C), oil molecules further break down into natural gas (methane).
    • If the temperature continues rising, most hydrocarbons decompose into gas and carbon residues.

IMPORTANCE OF THE CATAGENESIS PROCESS

• Primary process for petroleum formation.
• Enables hydrocarbon synthesis through the thermal breakdown of organic matter.
• Determines the density and composition of crude oil.
• WHAT HAPPENS AFTER CATAGENESIS?
  • If the temperature exceeds 120°C, catagenesis transitions into metagenesis, where lighter hydrocarbons continue to break down.
  • In this phase, natural gas production becomes dominant as heavier hydrocarbons decompose further.
  • Thus, catagenesis is a crucial stage in petroleum formation, making it possible for the fossil fuels we use today to exist.

HISTORY OF PETROLEUM PRODUCTION

• Crude oil, in its raw form, has limited value. However, its significance has evolved dramatically over time.
• Before 1859, oil that naturally seeped from the ground or was manually extracted had various uses:
  • Waterproofing ships
  • As an adhesive in construction
  • For flaming projectiles
  • In medicinal ointments
• After 1859, petroleum became a driving force in the global economy. Today, the world heavily depends on a continuous oil supply—without it, most human activities would come to a standstill.
  • Petroleum accounts for 60% of global shipping (by tonnage).
  • It fuels and lubricates trucks, trains, airplanes, and automobiles.
  • Ships run on fuel oil, while roads are paved with petroleum-based materials.
  • The steel industry relies on petroleum-derived coke.
  • Natural gas, extracted alongside petroleum, is another key energy source.
  • Petrochemical industries use petroleum derivatives as raw materials for countless products.
• From a simple natural resource to an economic powerhouse, petroleum has shaped modern civilization and continues to be an essential part of our daily lives.

THE SHIFT FROM WHALE OIL TO PETROLEUM

• In the 1850s, most households relied on whale oil or animal fats for lighting. However, over-hunting caused whale oil prices to skyrocket, peaking in the mid-1850s.
  • Whale oil (1845-1855): $1.77 per gallon
  • Lard oil (a cheaper but smoky alternative): $0.90 per gallon
• As whale oil became scarce and expensive, alternatives were urgently needed.
• The Invention of the Kerosene Lamp
  • 1857: Michael Dietz invented the flat-wick kerosene lamp, providing a cleaner-burning alternative to animal fats.

THE BIRTH OF THE PETROLEUM INDUSTRY

• August 27, 1859: Edwin L. Drake struck oil near Titusville, Pennsylvania, drilling a 69-foot (21 m) deep well that produced 35 barrels per day.
  • Drake’s oil price: $20 per barrel (cheaper than whale oil)
  • Daily earnings in 1861: $700 (~$5 million per year in 2002 dollars)
• Although the Chinese had drilled for oil 2,200 years earlier, Drake’s success sparked the Pennsylvania oil rush, transforming the energy industry.
• This milestone marked the shift from whale oil to petroleum, laying the foundation for modern oil production.

COMPOSITION OF CRUDE OIL

• Crude oil is a complex mixture of hydrocarbons, primarily composed of:
  • Carbon (83-87%)
  • Hydrogen (12-14%)
• It contains various hydrocarbon types, including:
  • Paraffins
  • Naphthenes
  • Aromatic hydrocarbons
  • Gaseous hydrocarbons ($CH₄$ to $C₄H₁₀$)
• Non-hydrocarbon components (in smaller amounts):
  • Sulfur, nitrogen, and oxygen compounds
  • Minerals (Heavier crude oils contain more sulfur)

Composition of crude-oil

• The (H/C) ratios affect the physical properties of crude oil.
• As the hydrogen to carbon ratio decreases, the gravity and boiling point of the hydrocarbon compounds increases.
• Moreover, the higher the hydrogen to carbon ratio of the feedstock, the higher its value is to a refinery because less hydrogen is required.

Crude Oil Classification

• Light Crude Oil
  • Liquid petroleum with low density and free-flowing at room temperature.
  • Low viscosity, low specific gravity, and high API gravity due to high proportion of light hydrocarbon fractions.
  • Generally has a low wax content.
• Heavy Crude Oil
  • Any type of crude oil that does not flow easily.
  • High density or specific gravity compared to light crude oil.
• Pricing
  • Light crude oil receives a higher price due to a higher percentage of gasoline and diesel fuel production.
• Environmental Impact
  • Heavy crude oil has more negative impact as its refinement requires advanced techniques and contaminants.
• Benchmark
  • The sweet light crude oil Western Texas Intermediate (WTI) is used as a benchmark in oil pricing.
• Additional classifications
  • Based on physical characteristics and chemical composition, described with terms such as “sweet,” “sour,” “light,” and “heavy.”

Hydrocarbon Classification

• Hydrocarbons are classified into three main types based on their carbon– carbon bonds:
  • Saturated hydrocarbons: Contain only single bonds.
    • Alkanes (paraffins): Acyclic (linear or branched).
    • Cycloalkanes (naphthenes): Cyclic structures.
  • Unsaturated hydrocarbons: Contain double or triple bonds.
    • Alkenes (olefins): Have double bonds.
    • Alkynes: Have triple bonds.
  • Aromatic hydrocarbons: A special class of cyclic compounds, related to benzene.
• These classifications determine the chemical reactivity and uses of hydrocarbons in petroleum processing

Simple hydrocarbons and their variations

BASIC PETROCHEMICALS

• C1 group
  • Methane, CO – H2 synthesis, synthesis gas derivatives
• C2 group
  • Ethane, ethylene, ethylene derivatives, acetylene
• C3 group
  • Propane, propylene and propylene derivatives
• C4, C5 group
  • Butadiene, Butanes, Butenes, Pentane, Pentene, Isoprene, Cyclopentadiene
• Aromatic
  • Benzene, Toluene , Xylenes Naphthalene, BTX derivatives

PONA: Paraffins, Olefins, Naphthenes, and Aromatics

• The hydrocarbons present in crude petroleum are classified into three general types:
  • 1-paraffins,
  • 2-naphthenes,
  • 3-and aromatics.
• In addition, there is a fourth type, olefins, that is formed during processing by the dehydrogenation of paraffins and naphthenes.
• Hydrocarbons are classified as:

Detailed Composition of crude-oil

Detailed Composition of crude-oil

Chemical Structure Examples of Crude Chemistry

• Paraffins
  • Paraffins refer to alkanes such as methane, ethane, propane, n- and iso-butane, and n- and iso-pentane.
  • These saturated hydrocarbons are primarily obtained as a gas fraction from the crude distillation unit and are widely used as fuel gases, feedstocks for petrochemical processes, and key components in liquefied petroleum gas (LPG).
• Olefins (Alkenes)
  • Alkenes, such as ethylene, propylene, and butylenes, are highly reactive hydrocarbons due to the presence of carbon–carbon double bonds.
  • Unlike paraffins and naphthenes, they are not naturally abundant in crude oil.
  • However, they are produced in significant quantities during various refining processes, including catalytic cracking, alkylation, and steam cracking.
  • These processes break down larger hydrocarbons into smaller, more valuable compounds.
  • Alkenes serve as key building blocks in the petrochemical industry, playing a crucial role in the production of plastics, synthetic fibers, and numerous chemical intermediates.
• Naphthenes
  • Naphthenes, also known as cycloalkanes, include compounds such as cyclopropane and methylcyclohexane, which are naturally present in crude oil.
  • Unlike aromatics, naphthenes do not significantly contribute to the octane number of fuels.
  • As a result, in refinery processes like catalytic reforming, these compounds are often converted into aromatics, which possess higher octane numbers and enhance the quality of gasoline.
• Aromatics
  • Aromatics, including benzene, toluene, and o/m/p-xylene, are naturally present in crude oil.
  • These compounds play a crucial role in enhancing the octane number of fuels, making them valuable for gasoline production.
  • In refinery processes, the goal is to maximize the yield of aromatics to improve fuel quality and meet performance requirements.

Petrolün Kimyasal Özellikleri (Chemical Properties of Petroleum)

• Petrol ,alifatik (parafinler, olefinler, naftenler) ve aromatik hidrokarbonlardan oluşmaktadır.
• Parafinler (Alkan): $C<em>nH</em>{2n+2}$
• Olefinler (Alken): $C<em>nH</em>{2n}$
• Asetilen (Alkin): $C<em>nH</em>{2n-2}$
• Aromatik (Benzen): $C<em>nH</em>{2n-6}$

PRODUCTS COMPOSITION

• Number of Carbon Atoms and Boiling Ranges

PRODUCT COMPOSITION

• Liquefied Petroleum Gas (LPG)
  • Liquified petroleum gas is a group of hydrocarbon-based gases derived from crude oil refining or natural gas fractionation.
  • They include ethane, ethylene, propane, propylene, normal butane, butylene, isobutane and isobutylene.
  • For convenience of transportation, these gases are liquefied through pressurization.
• Gasoline
  • Gasoline is classified by octane ratings (conventional, oxygenated and reformulated) into three grades: Regular, Midgrade and Premium.
• Kerosene
  • Kerosene is a light petroleum distillate that is used in space heaters, cook stoves and water heaters and which is suitable for use as a light source.
• Jet Fuel
  • This category comprises both gasoline and kerosene and meets specifications for use in aviation turbine power units
• Diesel Fuel
  • The quality of diesel fuels can be expressed as cetane number or cetane index.
  • The cetane number (CN) is expressed in terms of the volume percent of cetane ($C<em>{16}H</em>{34}$) which has high ignition (CN = 100) in a mixture with alpha-methyl-naphthalene ($C<em>{11}H</em>{10}$) which has low ignition quality (CN = 0).
• Fuel Oil
  • The fuel oils are mainly used in space heating and thus the market is quite high specially in cold climates.
  • No. 1 fuel oil is similar to kerosene and No. 2 fuel oil is very similar to diesel fuel.
  • Heavier grades of No. 3 and 4 are also available.
• Residual Fuel Oil
  • It is mainly composed of vacuum residue.
  • Critical specifications are viscosity and sulphur content.
  • Low sulphur residues are in more demand in the market.
• Lube Oil
  • Lubricants are based on the viscosity index.
  • Paraffinic and naphthenic lubricants have a finished viscosity index of more than 75.
• Asphalt
  • Asphalt is an important product in the construction industry and comprises upto 20% of products.
  • It can be produced only from crude containing asphaltenic material.
• Petroleum Coke
  • Carbon compounds formed from thermal conversion of petroleum containing resins and asphaltenes are called petroleum cokes.
  • Fuel grade coke contains about 85% carbon and 4% hydrogen. The balance is made up of sulphur, nitrogen, oxygen, vanadium and nickel.

Petroleum Fractions: Boiling Points and Uses

Important characterization properties

• Numerous important feed and product characterization properties in refinery engineering include
• Physical Property Characterization Data
  • API gravity
  • Watson Characterization factor
  • Viscosity
  • Sulfur content
  • True boiling point (TBP) curve
  • Pour point
  • Flash and fire point
  • ASTM distillation curve
  • Octane number
  • Refractive Index

API Gravity

• API gravity of petroleum fractions is a measure of density of the stream.
• The gravity of crude oil determines its price commercially. It is generally expressed as API gravity defined as:

$API = (141.5/SG) - 131.5$

• where SG is the specific gravity defined as the density of the crude oil relative to the density of water both at 15.6 C (60 F).
• The API gravity can range from 8.5 for very heavy crudes to 44 for light crudes.
• Crude oils can generally be classified according to gravity as shown in Table.
• BRENT CRUDE OIL
  • Brent blend is a light crude oil (LCO), though not as light as West Texas Intermediate (WTI).
  • It contains approximately 0.37% of sulphur, classifying it as sweet crude, yet not as sweet as WTI.
  • Brent Crude has a density of approximately 835 kg/$m^3$, being equivalent to a specific gravity of 0.835 or an API gravity of 38.06.
• BRENT CRUDE OIL PRICE
  • The benchmark crude, used as a reference price for buyers and sellers is also known as London Brent, Brent Blend and Brent Petroleum.
  • 1 Barrel Brent Petrol ~94.5 USD (15.02.22)
  • 1 Barrel Brent Petrol ~83.6 USD (04.03.24)
• The measurement of an "oil barrel" originated in the early Pennsylvania oil fields.
  • The Drake Well, the first oil well in the US, was drilled in Pennsylvania in 1859, and an oil boom followed in the 1860s.
  • When oil production began, there was no standard container for oil, so oil and petroleum products were stored and transported in barrels of different shapes and sizes.
  • Some of these barrels, such as the 42-US-gallon (159 L) barrels (based on the old English wine measure), were used for other products.
  • Barrel (unit) bbl for “blue barrel.”

Viscosity

• The resistance to flow or the pumpability of the crude oil or petroleum fraction is indicated by the viscosity.
• More viscous oils create a greater pressure drop when they flow in pipes.
• Viscosity is a very important property for the heavy products obtained from the crude oil.
• The viscosity acts as an important characterization property in the blending units associated to heavy products such as bunker fuel.
• Typically, viscosity of these products is specified to be within a specified range and this is achieved by adjusting the viscosities of the streams entering the blending unit.

Flash and fire point

• Flash and fire point are important properties that are relevant to the safety and transmission of refinery products.
• Flash point is the temperature above which the product flashes forming a mixture capable of inducing ignition with air.
• Fire point is the temperature well above the flash point where the product could catch fire.
• These two important properties are always taken care in the day to day operation of a refinery.

Differences Between Flash Point and Fire Point

Cloud Point & Pour point

• When a petroleum product is cooled, first a cloudy appearance of the product occurs at a certain temperature. This temperature is termed as the cloud point.
• Upon further cooling, the product will ceases to flow at a temperature. This temperature is termed as the pour point.
• The pour point is defined as the lowest temperature at which the sample will flow. It indicates how easy or difficult it is to pump the oil, especially in cold weather.
• It also indicates the aromaticity or the paraffinity of the crude oil or the fraction.
• A lower pour point means that the paraffin content is low.

Key Points:

• ✅ Cloud Point < Pour Point → The cloud point is always higher than the pour point.
• ✅ Low Cloud Point & Pour Point → Ensures better fluidity in cold weather conditions.
• ✅ Fuel Quality & Filter Clogging → Particularly crucial for diesel fuels.

Watson characterization factor

• The Watson characterization factor is usually expressed as

$K = (T_B)^{1/3} / specific gravity$

• Where $T_B$ is the average boiling point in degrees R taken from five temperatures corresponding to 10, 30, 50, 70 and 90 volume % vaporized.
• Typically Watson characterization factor varies between 10.5 and 13 for various crude streams. A highly paraffinic crude typically possesses a K factor of 13. On the other hand, a highly naphthenic crude possesses a K factor of 10.5.
• Therefore, Watson characterization factor can be used to judge upon the quality of the crude oil in terms of the dominance of the paraffinic or naphthenic components.

Key Points:

• ✅ Watson factor ranges between 10.5 - 13.
• ✅ High paraffin content crude oil → K ≈ 13
• ✅ High naphthene content crude oil → K ≈ 10.5
• ✅ The K-factor is a crucial indicator for predicting the behavior of crude oil during the refining process.
• 📌 Higher K value → Lighter & more paraffinic structure → Advantageous for high-yield fuels.
• 📌 Lower K value → Heavier & more naphthenic structure → Preferred for lubricants and specialized products.
• 📌 Critical parameter for crude oil processability and refinery operations.

TBP (True Boiling Point)/ASTM (American Society for Testing and Materials) distillation curves

• TBP (True Boiling Point) Distillation Curve
  • Used for detailed analysis of crude oil fractions.
  • Conducted under highly controlled laboratory conditions with low reflux ratios.
  • The boiling curve illustrates how different hydrocarbon components in crude oil separate based on temperature.
  • A critical analytical method for refining processes and determining the economic value of fractions.
  • Advantage: Provides precise determination of true boiling points.
  • Disadvantage: Time-consuming and expensive.
• ASTM (American Society for Testing and Materials) Distillation Curve
  • A faster and more practical method commonly used in the industry.
  • Analyzes how fractions separate at specific temperatures based on standard test procedures.
  • Primarily used for quality assessment of commercial petroleum products such as gasoline and diesel.
  • Advantage: Fast and easy to apply.
  • Disadvantage: Less precise than TBP, especially for heavy fractions.
• Using a crude TBP curve, cut points are defined as the temperatures that represent the limits of a distillate fraction.
• Cut Points Table

Octane number (gasoline)

• An octane number is a measure of the knocking tendency of