Petroleum refining (1 of 3)

Chemical Engineering Guy
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1. Introduction
2. Overview of the Petroleum Refining
3. Crude Oils
4. Products
5. Crude Oil Distillation (ATM/Vacuum)
6. Hydrotreatment
7. Gas Processing
8. Polymerization Unit
9. Isomerization Unit
10. Alkylation Unit
11. Catalytic Reforming
12. Fluid Catalytic Reformers (FCC)
13. Hydrocracking
14. Thermal Cracking & Coking
15. Secondary Processes
16. Conclusion

 Refining 
 Petrochemical 

Petrochemicals
5% are converted to
petrochemicals

 Typical Products in Petroleum Refining
 Mostly Fuels
 Asphalts & Coke

 Refining 
 Petrochemical 
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 Give an overall Overview of the Industry & Refineries
 Get to know the Products of a Petroleum Refinery
 Understand Unit Operations & Process conditions
 Atmospheric Distillation & Vacuum Distillation
 Crackers, Cokers, Alkylation Units, Reforming Units, etc…
 Pathways of several cuts
 Hydrotreatment, Desulfurization, Cracking, etc…
 Common terminology
 Reformate
 Cuts
 Alkylate
 Blending Pool, etc….

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 Crude oil is a multicomponent mixture
consisting of more than 108 compounds.
 Petroleum refining refers to the separation as
well as reactive processes to yield various
valuable products.
 Therefore, a key issue in the petroleum refining
is to deal with multicomponent feed streams
and multicomponent product streams.
See more in “Crude Oil” Section

 Usually, in chemical plants, we encounter
streams not possessing more than 10
components, which is not the case in petroleum
refining.
 Therefore, characterization of both crudes:
 Intermediate product
 final product streams
 is very important to understand the processing
operations effectively.
See more in “Crude Oil” Section
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 Will a Gasoline Engine run with Crude Oil?
 Will a Gas engine run on Crude Oil? Let's try it!
 https://www.youtube.com/watch?v=L99EybPORKk

 Petroleum refineries have goal to convert as
much of the barrel of crude oil into
transportation fuels which is economically
practical.
 These transportation fuels have boiling
points between 25 and 350°C.
 Refineries produce many profitable products
(petrochemicals) however, the high-volume
profitable products are the transportation
fuel gasoline, diesel and turbine (jet) fuels,
and the light heating oils.

 Although products such as lubricating oils,
refrigeration and transformer oils, and
petrochemical feedstocks are profitable.
 They amount to less than 5% of the total crude
oil charged to refineries.
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 The processing equipment indicated is for
processing crude oils of average gravities and
sulfur contents.
 Crude oils with low API gravities (high specific
gravities) and high sulfur contents require
additional hydrotreating equipment.
 The quality of crude oils processed by
worldwide refineries is expected to worsen
slowly in the future with the sulfur contents
and densities to increase.

 This will then make refineries require processing
the entire barrel of crude rather than just the
material boiling below (550°C).
 Sulfur restrictions on fuels, coke and heavy fuel oils
affects the bottom-of-the-barrel processing as well.
 These factors requires extensive refinery additions
modernization the shift in market requirements
among gasolines and reformulated fuels for
transportation challenges.

 Primary crude oil cuts in a typical refinery include:
 gases, light/heavy naphtha, kerosene, light gas oil, heavy gas oil and residue.
 From these intermediate refinery product streams several final product streams
such as:
 fuel gas, liquefied petroleum gas (LPG), gasoline, jet fuel, kerosene, auto diesel,
lubricants, bunker oil, asphalt and coke are obtained.

 Conceptually, a process refinery can be viewed upon as
a combination of both:
 physical and chemical processes
 Typically, the dominant physical process in a refinery is
the distillation process
 It enables the removal of:
 lighter components
 heavier components.
 Chemical processes such as alkylation and isomerisation
are equally important in the refinery engineering
 These processes enable the reactive transformation of
various functional groups to desired functional groups in
the product streams.
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 Typical Product distribution (from Barrel)
www.ChemicalEngineeringGuy.com 1 bbl = 158.99 L

 Resources:
 https://www.bp.com/content/dam/bp/en/corporate/pdf/energy-economics/statistical-
review/bp-stats-review-2018-full-report.pdf
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 Facts
 Reserves
 Production
 Consumption
 Prices & Markets
 Trading

 Energy developments:
 Primary energy consumption growth averaged 2.2% in 2017,
up from 1.2% last year and the fastest since 2013.
 This compares with the 10-year average of 1.7% per year.
 By fuel, natural gas accounted for the largest increment in
energy consumption, followed by renewables and then oil.
 Energy consumption rose by 3.1% in China.
 China was the largest growth market for energy for the 17th
consecutive year.

 The oil price (Dated Brent) averaged $54.19 per barrel, up
from $43.73/barrel in 2016.
 This was the first annual increase since 2012.
 Global oil consumption growth averaged 1.8%, or 1.7
million barrels per day (b/d), above its 10-year average of
1.2% for the third consecutive year.
 China (500,000 b/d) and the US (190,000 b/d) were the single
largest contributors to growth.
 Global oil production rose by 0.6 million b/d, below
average for the second consecutive year.
 qUS (690,000 b/d) and Libya (440,000 b/d) posted the largest
increases in output
 Saudi Arabia (-450,000 b/d) and Venezuela (-280,000 b/d) saw
the largest declines.
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 Relevant:
 North America  22%
 Middle East  34%
 China is not a big producer!
 OPEC  43%

 TASK:
 Play from 1980 to 2017
 https://www.eia.gov/beta/international/

 Raw Material:
 Crude Oil
 Water/salts/sediments
 Gas
 Slag, slurry, dust
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 Crude distillation unit (CDU)
 Vacuum distillation unit (VDU)
 Thermal cracker & Cokers
 Hydrotreaters
 Fluidized catalytic cracker
 Naphtha splitter
 Reformer
 Alkylation and isomerisation
 Gas treating units
 Blending pools
www.ChemicalEngineeringGuy.com See more in the respective “Process” Section

 SEPARATION PROCESSES
 Distillation & Absorption
 Extraction
 Crystallization
 Adsorption
 PRIMARY DISTILATION (Atmospheric Distillation)
 Refinery gases, LPG , Gasolines or naphtha (light/heavy), Kerosene, Jet fuel, Diesel oil,
domestic heating oils, Heavy Industrial fuels
 SECONDARY DISLLATION (Vacuum Distillation)
 Light Distillate
 Middle distillate
 Heavy distillate
 Asphalt/bitumen
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 Process for Improvement of Properties
 Catalytic reforming
 Isomerisation
 Alkylation
 Thermal processes:
 Visbreaking
 Coking
 Catalytic Processes
 Catalytic cracking (FCC)
 Hydrocracking
 Steam reforming (Nat. Gas)
 Hydroconversion

 Hydrotreatment/hydrogenation
 Sweetening

 Acid gas processing
 Stack gas processing
 Waste water treatment process

 Typical Petroelum Refining Scheme
 Only a pre-heating
 Several Side-draws of Products
 Single Column
http://what-when-how.com/petroleum-
refining/upgrading-of-distillates/ Figure 1.6. Typical process scheme of a petroleum refinery.
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 LPG: Liquified Petroleum Gases
 LSRGO/HSRGO
 Light-Straight Run Gas Oil
 Heavy Run Gas Oil
 FCC: Fluid Catalytic Cracking
 HDT: Hydrotreatment
 DAO: De-asphalted Oil
 SDA: Solvent De-Asphalting Unit
http://what-when-how.com/petroleum-
refining/upgrading-of-distillates/ Figure 1.6. Typical process scheme of a petroleum refinery.

 Catalytic Reforming Unit
Figure 1.7. Typical process scheme of a catalytic reforming unit.
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Figure 1.8. Typical process scheme of an isomerization unit.

Figure 1.9. Typical process scheme of an alkylation unit.
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Figure 1.10. Typical process scheme of a polymerization unit.

 Visit  https://www.voestalpine.com/welding/downstream-app/PETROLEUM-REFINING
 Identify the several plants inside the refinery complex.
 Visbreaking Unit, Coker Plant, Alkylation Palnt, Isomerization Unit, Hydrocracking Unit, FCC
Unit, Hydrotreating Unit, CDU
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Fuel Gas
Sulfur
C3 LPG
C4 LPG
Kerosene
Premium Gasoline
Regular Gasoline
Auto Diesel
Heating Oil
Haring Diesel
Heavy Fuel Oil
Bunker Oil

 The unit has several sub-units
 Atmospheric distillation column
 Side strippers
 Heat exchanger network
 Feed de-salter
 Furnace
 Raw Materials:
 Crude Oil
 Five products are generated from the CDU
 Gas + Naphtha (to HDS Naphtha Unit)
 Kerosene(to HDS Light Gas Oil Unit)
 Light gas oil (LGO) (to HDS Light Gas Oil Unit)
 Heavy gas oil (HGO) (to HDS Heavy Gas Oil Unit)
 Atmospheric residue (to VDU)
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 Amongst the crude distillation products:
 naphtha, kerosene have higher product values
 Vs. gas oil and residue.
 Reactive transformations (chemical processes) are
inevitable to convert the heavy intermediate
refinery streams into lighter streams.
 Operating Conditions
 The temperature at the entrance of the furnace
where the crude enters is 200 – 280°C.
 It is then further heated to about 330 – 370°C inside
the furnace.
 The pressure maintained is about 1 barg.

 The VDU consists of:
 Main vacuum distillation column
 Side strippers
 VDU is also a physical process to obtain the desired
products.
 The pressure maintained is about 25 – 40 mm Hg.
 The temperature is kept at around 380 – 420°C.

 VDU Feedstock:
 Atmospheric Residue (from CDU)
 VDU Products:
 Light Vacuum Gas Oil (LVGO) (to HDS Light Gas Oil Unit)
 Heavy Vacuum Gas Oil (HVGO) (to HDS Light Gas Oil Unit)
 Vacuum residue (to Thermal Cracking / Coking Unit)
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 Thermal cracker involves a chemical cracking
process followed by the separation using
physical principles (boiling point differences)
to yield the desired products.
 Feedstock:
 Vacuum Residue (from VDU)
 Products
 Cracked Naphtha + Gas (to HDS Naphtha Unit)
 Cracked Gasoil (to HDS Light Gas Oil Unit)
 Thermal cracked residue (to Fuel Oil Blending)

 In some petroleum refinery configurations,
thermal cracking process is replaced with:
 Delayed coking process to yield coke as one of
the petroleum refinery products.
 The temperature should be kept at around 450 –
500°C
 larger hydrocarbons to become unstable and break
spontaneously.
 A 2-3 bar pressure must be maintained.

Fuel Gas
Sulfur
C3 LPG
C4 LPG
Kerosene
Premium Gasoline
Regular Gasoline
Auto Diesel
Heating Oil
Haring Diesel
Heavy Fuel Oil
Bunker Oil
HDS = Hydro De-sulfurization Units

 Sulfur content in the crude is significantly high.
 Products from CDU and VDU consist of
significant amount of sulfur.
 Sulfur removal is accomplished to remove
sulfur as H2S using Hydrogen.
 The H2 required for the hydrotreaters is
obtained from the reformer unit
 Here, heavy naphtha is subjected to reforming
to yield:
 High octane number reformer product
 Reformer H2 gas
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 Various hydrotreaters are used.
 Naphtha
 Diesel (Distillate)
 Heavy
 LVGO/HVGO hydrotreater:
 desulfurization occurs in two blocked operations
 Feedstock:
 Gas + Naphtha, Kerosene, LGO, HGO (from CDU)
 LVGO, HVGO (from VDU)
 Products:
 Desulfurized naphtha fraction (to C4 Separator)
 Desulfurized gas oil main product (to Kerosene Separator)
 LGO hydrotreating case, along with diesel main product, naphtha and gas to C5 fraction are
obtained as other products

 Only for kerosene hydrotreater
 no lighter product is produced in the hydrotreating operation.
 The operating conditions of a hydrotreater varies with the type of feed.
 Naphtha feed:
 the temperature may be kept at around 280-425°C
 the pressure be maintained at 200 – 800 psig.

 Typical Process
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 The unit is one of the most important units of the
modern refinery.
 Feedstock:
 Hydrotreated Heavy Vacuum Gas Oils (from Heavy Gas
Oil Hydrodesulfurization Unit)
 Products
 Gaseous FCC Products (to Gas Treating Unit)
 Unsaturated light ends (to Alkylation Unit)
 Light cracked naphtha (to Gasoline Blending Pool)
 Heavy cracked naphtha (to Gasoline Blending Pool)
 Cycle oil (to Gas Oil Blending Pool)
 Slurry (to Fuel Oil Blending Pool)

 Thereby, the unit is useful to
generate more lighter products
from a heavier lower value
intermediate product stream.
 Conceptually, the unit can be
regarded as a combination of
chemical and physical processes.
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 The gas fractions from various units need
consolidated separation
 This require stage-wise separation of the
gas fraction.
 All these units are conceptually regarded
as physical processes.
 Most oil and gas separators operate in the
pressure range of 20 – 1500 psi.

 Feedstock:
 C4-Separator
 HDS Naphtha (from HDS Naphtha Unit)
 C3-Separator
 Top Product (from C4-Separator)
 Cracked Light-Ends (from Reformer)
 C2-Separator
 Top Product (from C3-Separator)
 Products
 C4-Separator
 Top: C4+ Cut (to C3-Separator)
 Bottom  Desulfurized Light & Heavy Naphtha (to Naphtha
Splitter)
 C3-Separator
 Top: Saturated Light Ends (C3+) (to C2-Separator)
 Bottoms: C4 iso/n butanes * (to Butane Splitter)
 C2-Separator
 Fuel Gas + H2S (to Gas Treating Unit)
 C3s (propane) ** (to LPG blending pool)
*isomerization reactions, LPG and gasoline product generation.
** required for LPG product generation
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 The naphtha splitter unit consisting of a series of distillation
columns. These are Physical process
 Feedstock:
 Consolidated naphtha stream obtained (from several sub-units of
the refinery complex)
 Products (separation of)
 Desulfurized light naphtha (to Gasoline Blending Pool)
 Desulfurized heavy naphtha (to Reformer)
 The pressure is to be maintained between 1 kg/cm2 to 4.5 kg/cm2
 The operating temperature range should be 167 – 250°C

 Unlike naphtha splitter, these splitters
facilitate stream distribution and do not
have any separation processes built
within them
 Several Splitters are required:
 Butane
 Kerosene
 LVGO
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 The kerosene splitter is used to split:
 Kerosene to (kerosene blending pool)
 Kerosene to (Gas Oil blending pool )
 Butane splitter splits
 N-Butane to (LPG blending pool)
 N-Butane to (Gasoline blending pool)
 N-Butane to (Isomerization unit)
 LVGO
 Desulfurized LVGO to (Kerosene blending pool)
 Desulfurized LVGO to (Gas Oil blending pool)

 Heavy naphtha which does not have high octane
number is subjected to reforming in the reformer unit
 Feedstock:
 Desulfurized Heavy Naphtha (from Naphtha Splitter)
 Produces:
 Light ends (to C3 Separator)
 Reformer Gas H2 (to HDS Naphtha)
 Reformate with high octane number (to gasoline blending
pool)

 This unit produces high octane number
product that is essential to produce
premium grade gasoline as one of the
major refinery products.
 A reformer is regarded as a combination
of chemical and physical processes.
 The initial liquid feed should be pumped
at a reaction pressure of 5 – 45 atm
 the preheated feed mixture should be
heated to a reaction temperature of 495 –
520°C.

 Isomerization reaction is carried out in the
isomerization unit
 Feedstock:
 N-butane (from Butane Splitter)
 Products:
 Iso-butane (iC4) make-up (to Alkylation Unit)
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 The unsaturated light ends generated from the FCC process
are stabilized by alkylation process
 Feedstock
 Unsaturated Light-Ends (form FCC)
 Iso-butane (iC4) make-up (from isomerization unit)
 Product:
 C3s (to LPG blending)
 C4s (to LPG blending)
 Alkylate (to gasoline blending)
 The process yields alkylate product which has higher octane
number
 As isobutane generated from the separator is enough to meet
the demand in the alkylation unit
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 Alkylation:

 The otherwise not useful fuel gas and H2S stream generated
from the C2 separator has significant amount of sulfur.
 In the gas treating process, H2S is successfully transformed
into sulfur along with the generation of fuel gas
 Eventually, in many refineries, some fuel gas is used for
furnace applications within the refinery along with fuel oil
 Pressure from 150 psig to 3000 psig
 Feedstock:
 Gaseous FCC products (from FCC)
 Fuel gas + H2S (from C2-Separator)
 Products
 Clean Fuel Gas (a.k.a. sweet gas) (final product)
 Hydrogen Sulfide  Sulfur (final product)
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 All refineries need to meet tight product
specifications in the form of:
 ASTM temperatures
 Viscosities
 octane numbers
 flash point
 pour point.
 To achieve desired products with minimum
specifications of these important parameters,
blending is carried out.
 There are four blending pools in a typical
refinery.
 LPG
 Gasoline (Premium + Regular)
 Gas Oil
 Fuel Oil

 LPG pool allows blending of saturated C3s and C4s to generate:
 C3 LPG and C4 LPG

 The most important blending pool in the refinery complex is
the gasoline pool:
 Premium and Regular gasoline products are prepared by blending
appropriate amounts of:
 n-butane, reformate, light naphtha, alkylate and light cracked naphtha
 These two products are by far the most profit making products
of the modern refinery
 An emphasis is there to maximize their total products while
meeting the product specifications.

 The gasoil pool produces automotive diesel and
heating oil from kerosene (from CDU), LGO,
LVGO and slurry.
 In the fuel oil pool, haring diesel, heavy fuel oil
and bunker oil are produced from LVGO, slurry
and cracked residue.

 Crude Oils
 Crude Oil Content
 Hydrocarbons
 Paraffins
 Olefins
 Naphthenes
 Aromatics
 Asphaltenes
 Non-HC
 Sulfur, Nitrogen, Oxygen, Metals
 Characterization of Crude Oils
 API Gravity, Viscosity, TBP, Pour Point, etc…
 Crude Oils around the World
 WTI
 Brent
 Dubai

 Petroleum (also called crude oil) is a mixture of gaseous,
liquid , and solid hydrocarbon compounds.
 Petroleum is flammable and contains certain volatile
material
 Petroleum occurs in sedimentary rock deposits throughout
the world and also contains small quantities of nitrogen
oxygen and sulfur-containing compounds as well as trace
amounts of metallic constituents.

 Crude oil is a complex liquid mixture made up of a vast
number of hydrocarbon compounds that consist mainly
of carbon and hydrogen in differing proportions
 In addition, small amounts of organic compounds
containing:
 sulphur, oxygen, nitrogen
 Also, metals such as:
 vanadium, nickel, iron and copper are also present.
Element
Composition
(wt%)
Carbon 83.0–87.0
Hydrogen 10.0–14.0
Sulphur 0.05–6.0
Nitrogen 0.1–0.2
Oxygen 0.05–2.0
Ni <120 ppm
V <1200 ppm

 Color: Light brown to dark brown
 Sp.gr: 0.81—0.985
 Boiling range : 25 – 400oC
 Hydrocarbons C1- C70 (4000 compounds)
 Metals: V, Fe, Ni
 Sulfur componenets:
 H2S, Thiols (mercaptans), sulfides, di sulfides, poly sulfides and thiophenes

 Crude oils are classified as:
 Paraffin base:
 The presence of paraffin wax in residue is reflected in the paraffin nature of the constituent.
 Olefin Base
 Naphthene base
 Aromatic Base
 Asphalt base
 high asphaltic content corresponds
with the naphthene properties of the fractions.
 Mixed base
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 The U.S. Bureau of Mines has developed a system which
classifies the crude according to two key fractions
obtained in distillation:
 No. 1 from 250 to 275 oC at atmospheric pressure
 No. 2 from 275 to 300 oC at 40 mmHg pressure.
 The API gravity of these fractions varies depending
upon paraffinic and naphthenic grade of the crude
 Paraffin : API 40 for No. 1 and 30 for No. 2
 Naphthene : API < 30 for No. 1 oil and <=20 for No. 2 oil

 Hydrocarbons
 Paraffins
 Olefins
 Naphthenes
 Aromatics
 Asphaltenes
 Non-HC
 Sulfur
 Nitrogen
 Oxygen
 Metals
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 Paraffins, also known as alkanes, are saturated
compounds that have the general formula CnH²n+2,
where n is the number of carbon atoms.
 Paraffins refer to alkanes such as methane, ethane,
propane, n and iso butane, n and iso pentane.
 The simplest alkane is methane (CH4), which is also
represented as C¹.

 Normal paraffins (n-paraffins or n-alkanes) are unbranched straight-chain
molecules.
 These compounds are primarily obtained as a gas fraction from the crude
distillation unit.
 The paraffin series of hydrocarbons is characterized by the rule that the
carbon atoms are connected by a single bond and the other bonds are
saturated with hydrogen atoms.
 Crude oil contains molecules with up to 70 carbon atoms, and the number
of possible paraffinic hydrocarbons is very high .

 Isoparaffins (or isoalkanes)
 are branched-type hydrocarbons that exhibit structural isomerization.
 In other words, the molecules have the same formulas but different arrangements of
atoms, known as isomers.
 Butane and all succeeding alkanes can exist as straight-chain molecules (n-
paraffins) or with a branched- chain structure (isoparaffins).
 For example, butane and pentane have the following structural isomers:

 The general formula is CnH2n.
 Olefins are generally not present in crude oil, however these are formed during
processing by the dehydrogenation of paraffins and naphthenes.
 They are very similar in structure to paraffins but at least two of the carbon atoms are
joined by double bonds.
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 Olefins are generally undesirable in finished products:
 double bonds are reactive
 compounds are more easily oxidized and polymerized to form gums and varnishes.
 Olefins containing five carbon atoms have high reaction rates with compounds in the
atmosphere
 They form pollutants and, even though they have high research octane numbers, are
considered generally undesirable.

 Diolefins are very undesirable in products:
 they are so reactive
 Will polymerize  plugging compounds.
 Some diolefins (containing two double bonds) are also formed during processing, but
they react very rapidly with olefins to form high-molecular-weight polymers
consisting of many simple unsaturated molecules joined together.

 Cycloparaffins (CnH2n)(naphthenes):
 saturated hydrocarbons containing one or more rings
 each of which may have one or more paraffin side-chains
 AKA alicyclic hydrocarbons
 There are many types of naphthenes present in crude oil, but except for the lower-
molecular-weight such as cyclopentane and cyclohexane, are generally not handled as
individual compounds.
 They are classified according to boiling range and their properties determined with the
help of correlation factors:
 Characterization (Kw) factor
 Correlation index (CI) .
 The cyclic hydrocarbons, both naphthenic and aromatic, can add paraffin side chains in
place of some of the hydrogen attached to the ring carbons and form a mixed structure.

 Aromatics (CnH2n-6) hydrocarbons containing one or more aromatic
nuclei such as:
 benzene, toluene, xylene
 Contain ring systems that may be linked up with (substituted)
naphthalene rings or paraffin side-chains.
 They are unsaturated cyclic compounds composed of one or more
benzene rings
 Light petroleum fractions contain mono-aromatics, which have one
benzene ring with one or more of the hydrogen atoms substituted by
another atom or alkyl groups.
 Their presence in gasoline increases the octane number.

 Asphaltenes are:
 Dark brown friable solids
 Do not have definite melting point
 Usually leave carbonaceous residue on heating
 The physical properties of crude oils, such as the specific gravity (or API),
are considerably influenced by high-boiling constituents
 Most heteroatoms (sulphur, nitrogen and metals) concentrate here
 It is therefore important to characterize the heaviest fractions of crude
oils in order to determine their properties and ease of processing.
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 They are made up of condensed polynuclear aromatic layers
linked by saturated links.
 These layers are folded, creating a solid structure known as a
micelle.
 Their molecular weights span a wide range, from a few
hundred to several million.
 Asphaltenes are separated from petroleum in the laboratory
using non-polar solvents such as pentane and n-heptane.
 Liquefied petroleum fractions (propane and butane) are used
commercially in de-asphalting residues and lube stock oils.
 Asphaltenes will:
 tend to precipitate inside the pores of rock formations, well heads
and surface processing equipments.

 In refinery operations, asphaltenes have markedly adverse effects on
the processability of crude oils.
 They will:
 lead to coke formation
 metal deposition on the catalyst surface (catalyst deactivation)
 Asphaletenes will be related to the Carbon residue
 It is mostly determined by distillation to a coke residue in the absence
of air.
 The carbon residue is roughly related to the asphalt content of the
crude and to the quantity of the lubricating oil fraction that can be
recovered.
 In most cases the lower the carbon residue, the more valuable the
crude.
 This is expressed in terms of the weight percent carbon residue by
either the Ramsbottom (RCR) or Conradson (CCR) .

 Resins are polar molecules in the molecular weight
range of 500–1000
 These are insoluble in liquid propane but soluble in
n-heptane.
 It is believed that the resins are responsible for
dissolving and stabilizing the solid asphaltene
molecules in petroleum.
 The resin molecules surround the asphaltene
clusters (micelles) and suspend them in liquid oil.
 Because each asphaltene is surrounded by a
number of resin molecules, the content of resins in
crude oils is higher than that of the asphaltenes.

 Paraffins: Paraffins refer to alkanes such as methane, ethane, propane, n and iso butane, n and iso pentane. These
compounds are primarily obtained as a gas fraction from the crude distillation unit.
 Olefins: Alkenes such as ethylene, propylene and butylenes are highly chemically reactive. They are not found in
mentionable quantities in crude oil but are encountered in some refinery processes such as alkylation.
 Naphthenes: Naphthenes or cycloalkanes such as cyclopropane, methyl cyclohexane are also present in the crude oil.
These compounds are not aromatic and hence do not contribute much to the octane number. Therefore, in the
reforming reaction, these compounds are targeted to generate aromatics which have higher octane numbers than the
naphthenes.
 Aromatics: Aromatics such as benzene, toluene o/m/p-xylene are also available in the crude oil. These contribute
towards higher octane number products and the target is to maximize their quantity in a refinery process.
 Napthalenes: Polynuclear aromatics such as naphthalenes consist of two or three or more aromatic rings. Their
molecular weight is usually between 150 – 500.
 Resins: Resins are polynuclear aromatic structures supported with side chains of paraffins and small ring aromatics.
Their molecular weights vary between 500 – 1500. These compounds also contain sulphur, nitrogen, oxygen, vanadium
and nickel.
 Asphaltenes: Asphaltenes are polynuclear aromatic structures consisting of 20 or more aromatic rings along with
paraffinic and naphthenic chains. A crude with high quantities of resins and asphaltenes (heavy crude) is usually targeted
for coke production.

 Sulfur
 Nitrogen
 Oxygen
 Metals

 Usually, crude oil has both organic and inorganic sulphur in
which the inorganic sulphur dominates the composition.
 Sulfur content & API gravity are two properties which have the
greatest influence on the value of crude oi
 Crude oil sulphur content consists of 0.5 – 5 wt % of sulphur
 Organic sulphur compounds such as thiophene, pyridine also
exist in the crude oil.
 Solid Sulfur will be produced form Hydrogen Sulfide in the Claus
Process

 Crudes with greater than 0.5% sulfur generally require more
extensive processing than those with lower sulfur content.
 High sulphur content are termed as sour crude.
 Low sulphur content are termed as sweet crude.
 It is estimated that about 80 % of world crude oil reserves are sour.
 Removal will require additional hydrogen requirements in the
hydrotreaters
 Operating conditions of the hydrotreaters is significantly intense
when compared to those of light crude oils
 Continuous growing environmental legislations indicate
technology and process development/improvement on the
processing of organic sulphur compounds.
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 These compounds do not exceed 2 % by weight in the crude
oil.
 Examples of Oxygen Containing Compounds
 Alcohols
 Phenols
 Ethers
 Acetic and benzoic acids
 Esters
 Anhydrides
 These compounds cause corrosion and therefore needs to be
effectively handled.
 A phenomenally high oxygen content indicates that the oil has
suffered prolonged exposure to the atmosphere.

 Most produced water contains salts that can cause problems in
production and refining, when solids precipitate to form scale on
process equipment.
 Mostly Calcium, Magnesium, Sodium and Potassium Chlorides
 The salts also accelerate corrosion in piping and equipment.
 The salt content of crude oil almost always consists of salt dissolved
in small droplets of water that are dispersed in the crude.
 Sometimes the produced oil contains crystalline salt, which forms
because of pressure and temperature changes and because of
stripping of water vapor as the fluid flows up the wellbore and
through the production equipment.
 Desalting is required if salt content of the crude
 is greater than 10 lb/ 1000 bbl

 High nitrogen content is undesirable in crude oils
because organic nitrogen compounds:
 poisoning of catalysts used in processing
 corrosion problems
 gum formation in finished products
 Crudes containing nitrogen more than 0.25% by weight
require special processing to remove the nitrogen
 More denser/viscous/asphaltic the oil:
 the higher its nitrogen content.

 Nitrogen compounds are more stable than sulphur compounds and therefore are
harder to remove.
 The nitrogen compounds in crude oils may be classified as basic or non-basic.
 Basic nitrogen compounds consist of pyridines.
 Non-basic nitrogen compounds, which are generally of pyrrole types.

 Typical content:
 nickel, vanadium, and copper
 Measured in ppm
 From a few parts per million to more than 1000
ppm.
 Small quantities of some of these metals can
severely affect the activities of catalysts
 Vanadium > 2 ppm in fuel oils:
 leads to severe corrosion to turbine blades
 deterioration of refractory furnace linings and stacks.
 The metallic content may be reduced by solvent
extraction with propane or similar solvents as the
organometallic compounds are precipitated with
the asphaltenes and resins.

 Trading: Density, API Gravity
 Transportation: RVP, Pour Point, KV, Wax content
 Contamination: Salt content, BS&W*
 Processability: Sulfur, Nitrogen, TAN*, Asphaltene, MCR*
 Cracking Point: ASTM Distillation
 LPG Potential: Light hydrocarbons (GC)
 Classification: Characterization factor
*Reid Vapor Pressure
*Basic sediment and water (BS&W)
*Total Acid Number (TAN)
*Micro Carbon Resirue (MCR)

 Density/API gravity
 Viscosity
 Sulfur content
 True boiling point (TBP) curve/assay
 Cloud/Pour point
 Flash and fire point
 ASTM distillation curve
 Correlation Index
 Watson Characterization factor
 Cetane & Octane
number
 C:H Ratio Test
 Diesel Index
 Redi Vapor Pressure
 Aniline Point
 Flash/Fire Point
 Smoke Point
 Acidity
 Salt Content
 Gum Content
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 API gravity of petroleum fractions is a measure of density
of the stream.
 Usually measured at 60 oF, the API gravity is expressed as
 Where specific gravity is measured at 60 oF.
 According to the above expression
 10 oAPI gravity indicates a specific gravity of 1 equivalent to
water specific gravity

 Lighter API gravity value is desired:
 More amount of gas fraction, naphtha and gas oils can
be produced from the lighter crude oil than with the
heavier crude oil.
 Typical Range of API Gravity:
 10oAPI - 50oAPI
 Most crudes fall in the
 20o API - 45o API range.

 API gravity always refers to the liquid sample at 60 oF (15.6 oC).
 API gravities are not linear and, therefore, cannot be averaged.
 For example, a gallon of 20o API gravity hydrocarbons when
mixed with a gallon of 30oAPI hydrocarbons will not yield two
gallons of 25o API hydrocarbons
 On the other hand Specific gravities of different oils can be
averaged

 Viscosity is a measure of the flow properties of the refinery stream.
 Typically in the refining industry, viscosity is measured in terms of:
 centistokes (termed as cst)
 saybolt seconds
 redwood seconds.
 Usually, the viscosity measurements are carried out at 100°F and
210°F.
 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.

 Materials having viscosity less than 10,000 centipoises (cp) are conventional
petroleum and heavy oil.
 Tar sand bitumen has a viscosity greater than 10,000 cp.
 In order to classify petroleum, heavy oil, and bitumen the use of a single parameter
such as viscoity is not enough.

 The boiling range of the crude gives an
indication of the quantities of the various
products present.
 The most useful type of distillation is known
as a true boiling point (TBP) distillation
 Common test  ASTM D-285 distillations
 Typical Conditions: 15:5 distillation (D- 2892)
 The 15:5 distillation is carried out using 15
theoretical plates at a reflux ratio of 5:1
 Both these distillation curves are measured at 1
atm pressure.

 Difference in method:
 TBP curve is measured using:
 batch distillation
 no less than 100 trays
 very high reflux ratio
 ASTM distillation is measured:
 in a single stage apparatus without any reflux.
 does not indicate a good separation of various
components
 indicates the operation of the laboratory setup far
away from the equilibrium.

 Simulation software will calculate TBP and cuts

 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.

 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.
 Both pour and cloud points are important properties of
the product streams as far as heavier products are
concerned.

 Pour point is the lowest temperature at which oil will move, pour ,
or flow when it is chilled without disturbance under definite
conditions*
 The pour point of the crude oil, in oF or oC, is a rough indicator of
the relative paraffinicity and aromaticity of the crude.
 The lower the pour point:
 the lower the paraffin content
 the greater the content of aromatics.
 Tar sand bitumen is a naturally occurring material that is immobile
in the deposit
www.ChemicalEngineeringGuy.com (ASTM D97)*

 More direct chemical information is desirable and can be supplied
by means of the correlation index (CI).
 The CI, developed by the U.S. Bureau of Mines, is based on.:
 Plot of specific gravity vs. the reciprocal of the boiling point in Kelvin .
 Common values:
 For pure hydrocarbons, the normal paraffin series is given value of CI=0
 For benzene CI = 100. CI= 473.7d - 456.8 + 48,640/T(K)
 Where,
 TK for a petroleum fraction is the average boiling point (K)
 ‘d’ is the specific gravity

 CI Values
 between 0 and 15 : indicates a predominance of paraffin hydrocarbons in the fraction.
 CI Values 15 to 50 : indicates predominance of either naphthenes or of mixtures of
paraffins, naphthenes, and aromatics.
 CI values more than 50 : indicates a predominance of aromatic species.

 Characterization factors are useful because they remain
reasonably constant for chemically similar hydrocarbons.
 It is a quick ratio between mean average boiling point and
specific gravity
 A characterization factor of
 12.5 or greater  paraffinic in nature.
 10-12.5  more naphthenic or aromatic components.
 10 or less  Highly aromatic hydrocarbons

 Examples of Waston Factor

 There are plenty of crude oil sources…
 Brent
 North Sea Area
 Dubai-Oman
 Middle East Reference
 Tapis
 South-East Asia Reference
 West Texas Intermediate
 USA/America Reference

 Sulfur – API Ratio
 Brent: North Sea Area
 Dubai-Oman: Middle East Reference
 Tapis: South-East Asia Reference
 West Texas Intermediate: USA/America Reference
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 West Texas Intermediate (WTI)
 also known as Texas light sweet
 is a grade of crude oil used as a benchmark in oil
pricing.
 This grade is described as Medium crude oi:
 low density
 low sulfur content.
 It is the underlying commodity of New York
Mercantile Exchange's oil futures contracts.

 WTI is a medium crude oil:
 API gravity of around 39.6
 Specific gravity of about 0.827
 This is lighter than Brent crude.
 The API rates Light oil as 41 Degrees API.
 WTI contains about 0.24% sulfur thus is rated as a sweet
crude oil (having less than 0.5% sulfur), sweeter than
Brent which has 0.37% sulfur.
 WTI is refined mostly in the Midwest and Gulf Coast
regions in the United States.

 Verify the typical conditions of crude oil in your country
 Click in following link:
 https://en.wikipedia.org/wiki/List_of_crude_oil_products
 Mexico:
Isthmus 33.4° 1.25%
Maya 21.8° 3.33%
Olmeca 37.3° 0.84%

 Crude Oil Cut
 Light Gases
 Naphtha (L/H)
 Gas Oils
 (L/H) Straight Run Gas oil
 Residues (Atm/Vaccum)
 Intermediate
 Reformate
 Alkylate
 Isomerate
 Polymer Gasoline
 (L/H) VGO
 Aromatics
 Product Specification
 Octane Rating
 Cetane Number
 Blended Product
 LNG
 LPG (P/B/Mix)
 Gasoline (R/P)
 Jet Fuel (A-1, Kerosene)
 Diesel
 Fuel Oils
 Waxes
 Lubes
 Asphalts
 Coke

 Identify:
 Raw Materials
 Atmospheric Products / Cuts
 Vacuum Products
 Blended Products
 Intermediates
 Gases
 Liquids
 Solids

Fuel Gas
Sulfur
C3 LPG
C4 LPG
Kerosene
Premium Gasoline
Regular Gasoline
Auto Diesel
Heating Oil
Haring Diesel
Heavy Fuel Oil
Bunker Oil
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 Generally, the products which dictate refinery design
are relatively few in number, and the basic refinery
processes are based on the large-quantity products:
 LPG, gasoline, diesel, jet fuel, home heating oils,
industrial fuels, cokes, etc…
 Storage and waste disposal are expensive!
 It is common to sell/use all of the items produced
from crude oil

 Typically, high-sulfur heavy fuel oil and fuel-grade coke,
must be sold at prices less than the cost of fuel oil.
 Economic balances are required:
 Determine whether certain crude oil fractions should be sold as
it is (i.e., straight-run)
 Or if further processed to produce products having greater value
 Usually the lowest value of a hydrocarbon product is its
heating value or fuel oil equivalent (FOE).
 Pricing depends on:
 location, demand, availability, combustion characteristics, sulfur
content, and competing fuels.

 ATM:
 Gas
 Naphtha (L/H)
 Jet Fuel
 (L/H) SRGO
 Residue (ATM)
 Vacuum:
 VGO (L/H)
 Residue (Vacuum)

 Straight Run
 2) Lt C.O. Distillate
 3) Lt S.R. Naphtha
 4) Hvy S.R. Naphtha
 5) S.R. Kerosene
 6) S.R. Middle Distillate
 7) S.R. Gas Oil
 8) Atm. Residue
 Vacuum X
 19) Lt. Vc. Distillate
 20) Hvy. Vc. Distillate
 21) Vc. Reside

 Fuel Gas
 Propane/Butane Gas
 C4 Feed  Alkyl Feed  Alkylate
 C5/C6 Isomerization Feed  Isomerate
 Hydrotreated Cuts
(Gasoline/Naphtha/Kerosene/Gas Oil)
 FCC Slurry
 FCC Light/Heavy Gas Oil
 FCC Cracked Gasoline
 Cracked Gas Oil
 Reformate
 Vacuum Gas Oil 1 & 2
 Atmospheric Residue
 Vacuum Residue
 Raffinates / Aromatic Extracts
 Dewaxed Oils
 Coker (Gasoline, l/h Gas Oil, Coke)
 Asphalt
 DAO (De-asphalted Oil)

 09) Polymerization Feed
 10) Polymerization Naphtha/Gasoline
 11) Alkyl Feed
 12) n-Butane
 13) Alkylate
 14) Isomerate
 15) Reformate
 16) Light ends (C3)
 17) Asphalt
 18) Lt HC Naphtha
 19) Coke
 20) Hvy V. Distillate / Lube Feedback
(14)
(18)
(16)
(17) (19)
(22)
(23)
(25)
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 21) V. Residue
 22) Dewaxed Oil (Raffinate)
 23) De-Oiled Wax
 24) Lt. FCC Distillate
 25) Extract
 26) Hvy. FCC Distillate
 27) FCC Clarified Oil
 28) N/A
 29) N/A
 30) Lt TC Distillate
 31) TC Residue
 32) N/A
 33) Raffinate
(14)
(18)
(16)
(17) (19)
(22)
(23)
(25)

 Sulfur Content
 Lead/Unleaded
 Oxygenates
 Antiknocking Agents
 Octane Rating
 Cetane Index
 Smokepoint

 It means low sulfur diesel fuel that meets
ASTM D 975 standards
 Grade Low Sulfur No. 1-D
 Grade Low Sulfur No. 2-D
 Diesel fuel containing higher amounts of
sulfur for off-road use is defined by EPA
regulations

 Any gasoline or gasoline-oxygenate blend which contains more
than 0.013 gram of lead per liter (0.05 g lead per U.S. gal).
 EPA defines leaded fuel as one which contains more than 0.0013
gram of phosphorus per liter (0.005 g per U.S. gal), or any fuel to
which lead or phosphorus is intentionally added.
 Main agent  Tetraethyllead
 First being mixed with gasoline (petrol) beginning in the 1920s as
a patented octane rating booster that allowed engine
compression to be raised substantially.
 Increased vehicle performance and fuel economy.

 EPA-registered gasoline additive suitable, when added in
small amounts to fuel, to reduce or prevent exhaust valve
recession (or seat wear) in automotive spark-ignition
internal combustion engines designed to operate on
leaded fuel.
 Gasoline or gasoline-oxygenate blend that contains a lead
substitute.

 In conjunction with "engine fuel" or
"gasoline" means any gasoline or gasoline-
oxygenate blend to which no lead or
phosphorus compounds have been
intentionally added
 It contains not more than 0.013 gram of
lead per liter (0.05 g lead per U.S. gal) and
not more than 0.0013 gram of phosphorus
per liter (0.005 g phosphorus per U.S. gal)
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 Oxygenates are usually employed as gasoline additives to reduce carbon monoxide and soot that is
created during the burning of the fuel.
 Compounds related to soot, like polyaromatic hydrocarbons (PAHs) and nitrated PAHs, are reduced also
 Alcohols:
 Methanol (MeOH)
 Ethanol (EtOH)
 Isopropyl alcohol (IPA)
 n-butanol (BuOH)
 Gasoline grade t-butanol (GTBA)
 Ethers:
 Methyl tert-butyl ether (MTBE)
 Tert-amyl methyl ether (TAME)
 Tert-hexyl methyl ether (THEME)
 Ethyl tert-butyl ether (ETBE)
 Tert-amyl ethyl ether (TAEE)
 Diisopropyl ether (DIPE)

 Oxygen Content of Gasoline
 % of oxygen by mass contained in a gasoline.
 Oxygenate
 It means an oxygen-containing, ash less, organic compound, such as an alcohol or ether,
which can be used as a fuel or fuel supplement.
 Total Oxygenate
 It means the aggregate total in volume percent of all oxygenates contained in any fuel

 Occurs when combustion of some of the air/fuel
mixture in the cylinder does not result from
propagation of the flame front ignited by the spark
plug
 One or more pockets of air/fuel mixture explode
outside the envelope of the normal combustion
front.
 The fuel-air charge is meant to be ignited by the
spark plug only, and at a precise point in the
piston's stroke.

 Knock occurs when the peak of the combustion
process no longer occurs at the optimum moment
for the four-stroke cycle.
 The shock wave creates the characteristic metallic
"pinging" sound, and cylinder pressure increases
dramatically.
 Effects of engine knocking range from
inconsequential to completely destructive.
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 Check out this video!
 A Knocked Engine
 https://www.youtube.com/watch?v=9X9qCH0VfCk
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 AKI:
 It means the arithmetic average of the Research Octane Number
(RON) and Motor Octane Number (MON)
 AKI = (RON + MON)/2.
 This value is called by a variety of names like
 octane rating
 posted octane
 (R + M)/2 octane
 Minimum Antiknock Index (AKI)
 The AKI shall not be less than the AKI posted on the product
dispenser or as certified on the invoice, bill of lading, shipping
paper, or other documentation

 Though irrelevant to the crude oil stream, the octane
number is an important property for many intermediate
streams that undergo blending later on to produce:
 Automotive gasoline
 Diesel
 Other fuels
 Typically gasoline tends to knock the engines.
 The knocking tendency of the gasoline is defined in terms
of the maximum compression ratio of the engine at which
the knock occurs.
 Therefore, high quality gasoline will tend to knock at
higher compression ratios and vice versa.
2,2,4-Trimethylpentane (iso-octane) (upper) has an octane
rating of 100 whereas n-heptane has an octane rating of 0.

 However, for comparative purpose, still one needs to have a
pure component whose compression ratio is known for
knocking.
 Iso-octane is eventually considered as the barometer for
octane number comparison.
 iso-octane was given an octane number of 100
 n-heptane is given a scale of 0.
 Therefore, the octane number of a fuel is equivalent to a
mixture of a iso-octane and n-heptane that provides the
same compression ratio in a fuel engine.

 Thus an octane number of 80 indicates:
 Fuel is equivalent to a mix of 80 vol % of isooctane and 20 % of n-heptane.
 Octane numbers are very relevant in the:
 Reforming
 Isomerization
 Alkylation processes
 The feed constituents do not consist of high quantities of constituents:
 straight chain paraffins
 non-aromatics (naphthenes).
 These processes enable the successful reactive transformations to
yield:
 long side chain paraffins (iso-)
 aromatics that possess higher octane numbers

 Motor Octane Number (MON)
 Numerical indication of a spark-ignition engine fuel's
resistance to knock obtained by comparison with reference
fuels in a standardized:
 ASTM D2700 Motor Method engine test.
 Minimum Motor Octane Number
 The minimum motor octane number shall not be less than
82 for gasoline with an AKI of 87 or greater.
 Research Octane Number (RON)
 Numerical indication of a spark-ignition engine fuel's
resistance to knock obtained by comparison with reference
fuels in a standardized:
 ASTM D2699 Research Method Engine Test.
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 What:
 A laboratory test method covering the quantitative
determination of the knock rating of liquid spark-ignition
engine fuel in terms of Research O.N., except that this test
method may not be applicable to fuel and fuel components
that are primarily oxygenates.
 The sample fuel is tested using:
 standardized single cylinder, four-stroke cycle
 variable compression ratio, carbureted
 RON Range:
 40 to 120 octane
 Typical commercial fuels RONS
 88 to 101

 Why:
 RON correlates with commercial automotive spark-ignition
engine antiknock performance under mild conditions of
operation.
 RON is used for measuring the antiknock performance of
spark-ignition engine fuels that contain oxygenates.

 How:
ASTM D2699 Standard Test Method for Research Octane Number of Spark-Ignition
Engine Fuel:
 The Research O.N. of a spark-ignition engine fuel is determined using a standard test
engine and operating conditions to compare its knock characteristic with those of PRF
blends of known O.N.
 Compression ratio and fuel-air ratio are adjusted to produce standard K.I. for the sample
fuel, as measured by a specific electronic detonation meter instrument system.
 A standard K.I. guide table relates engine C.R. to O.N. level for this specific method.
 The Engine Speed is set to run with 600 rpm.
 Typical specifications:
 Gasoline: Min 91 - 98
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 Cetane Number
 It means a numerical measure of the ignition performance of a diesel
fuel obtained by comparing it to reference fuels in a standardized
engine test
 Cetane Rating:
 Cetane number (cetane rating) is an indicator of the combustion
speed of diesel fuel and compression needed for ignition.
 It is an inverse of the similar octane rating for gasoline.
 The CN is an important factor in determining the quality of diesel
fuel, but not the only one; other measurements of diesel's quality
include:
 energy content, density, lubricity, cold-flow properties and sulphur
content.

 Cetane Index
 It means an approximation of the cetane number of distillate diesel
fuel
 It does not contain a cetane improver additive, calculated from the
density and distillation measurements.
 Cetane index is used as a substitute for the cetane number of
diesel fuel.
 Cetane index in some crude oil assays is often referred to as
Cetane calcule, while the cetane number is referred to as Cetane
measure.
 The cetane index is calculated based on the fuel's density and
distillation range (ASTM D86).

 Min. Cetane Number
 A minimum cetane number of 47.0 as determined by ASTM Standard Test
Method D 613.
 Generally, diesel engines operate well with a CN from 48 to 50.
 Fuels with lower cetane number have longer ignition delays, requiring more
time for the fuel combustion process to be completed.
 Hence, higher speed diesel engines operate more effectively with higher
cetane number fuels.
 The following increase CI
 Alkyl nitrates (principally 2-ethylhexyl nitrate)
 di-tert-butyl peroxide

 Methods: ASTM D976 and D4737.
 The older D976, or "two-variable equation" is outdated and should
no longer be used for cetane number estimation.
 still required by the United States Environmental Protection
Agency (EPA) as an alternative method for satisfying its
aromaticity requirement for diesel fuel.
 D4737 is the newest method and is sometimes referred to as
"the four-variable equation".
 D4737 is the same method as ISO4264.
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 The smoke point is a test measures the burning
qualities of kerosene and jet fuel.
 It is defined as the maximum height in mm, of a
smokeless flame of fuel.
 One of the standard tests is ASTM D1322.

 What:
 Determination of the smoke point of
kerosine and aviation turbine fuel.
 Smoke point
 The maximum height, in mm, of a
smokeless flame of fuel burned in a
wick-fed lamp of specified design.

 Why:
 The smoke point is related to the hydrocarbon type
composition of aviation fuels
 Aromatic fuel  smokier the flame.
 high smoke point  Low smoke fuel tendency
 The smoke point relates to 
 radiant heat transfer from the combustion products of the fuel.
 The smoke point provides a basis for correlation of fuel
characteristics with the life of the components:
 Radiant heat transfer exerts a strong influence on:
 the metal temperature of combustor liners
 other hot section parts of gas turbines

 How:
 ASTM D1322 Standard Test Method for Smoke Point of Kerosine and
Aviation Turbine Fuel:
 The sample is burned in an enclosed wick-fed lamp that is calibrated
daily against pure hydrocarbon blends of known smoke point.
 The maximum height of flame that can be achieved with the test fuel
without smoking is determined to the nearest 0.5 mm.
 Alternative test methods: IP 57
 Jet kerosene
 Min 18.00 - 25.00 mm

 Check out this video:
 https://www.youtube.com/watch?v=f-PRqAO22T8
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 LNG
 LPG (P/B/Mix)
 Gasoline (R/P)
 Jet Fuel (A-1, Kerosene)
 Diesel
 Fuel Oils
 Waxes
 Lubes
 Asphalts
 Coke

 Go to :
 https://www.bp.com/en_au/australia/products-services/fuels.htmlwww.ChemicalEngineeringGuy.com

 Liquefied Natural Gas (LNG)
 It means natural gas that has been liquefied at -126.1 EC ( 259 EF) and stored in
insulated cryogenic tanks for use as an engine fuel.
 Liquefied Petroleum Gas (LPG)
 It means a mixture of normally gaseous hydrocarbons, predominantly propane,
or butane, or both, that has been liquefied by compression or cooling, or both
to facilitate storage, transport, and handling
 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, n-butane, butylene,
i-butane and iso-butylene.
 For convenience of transportation, these gases are liquefied through
pressurization.

 Specifications
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 Petroleum naphtha is an intermediate hydrocarbon
liquid stream derived from the refining of crude oil
with CAS-no 64742-48-9.
 It is most usually desulfurized
 It is typically catalytically reformed
 this re-arranges or re-structures
the hydrocarbon molecules in the naphtha as well as
breaking some of the molecules into smaller molecules
to produce a high octane component
of gasoline (or petrol).

 There are hundreds of different petroleum crude
oil sources worldwide and each crude oil has its
own unique composition or assay.
 There are also hundreds of petroleum refineries
worldwide and each of them is designed to process
either a specific crude oil or specific types of
crude oils.
 Naphtha is a general term as each refinery
produces its own naphthas with their own unique
initial and final boiling points and other physical
and compositional characteristics.
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SOURCE:
https://en.wikipedia.org/wiki/Petroleum_naphtha

 The first unit operation in a petroleum refinery is the crude oil
distillation unit.
 The overhead liquid distillate from that unit is
called virgin or straight-run naphtha
 the distillate is the largest source of naphtha in most petroleum
refineries.
 It has:
 initial boiling point (IBP) of about 35 °C
 final boiling point (FBP) of about 200 °C
 it contains:
 paraffins, naphthenes (cyclic paraffins) and aromatic hydrocarbons ranging
 from those containing 4 carbon atoms to those containing about 10 or 11 carbon
atoms.

 The virgin naphtha is often further distilled into two
streams:
 a virgin light naphtha with an IBP of about 30 °C and a FBP of
about 145 °C containing most (but not all) of the
hydrocarbons with 6 or less carbon atoms
 a virgin heavy naphtha containing most (but not all) of the
hydrocarbons with more than 6 carbon atoms.
 The heavy naphtha has an IBP of about 140 °C and a FBP of
about 205 °C.

 The virgin heavy naphtha is usually processed in a catalytic
reformer
 light naphtha has molecules with 6 or fewer carbon atoms
 When reformed  crack into butane (C4) and lower
molecular weight hydrocarbons
 are not useful as high-octane gasoline blending components.
 Molecules with six carbon atoms (C6) tend to form aromatics
 undesirable due to the environmental regulations of a number of
countries limit the amount of aromatics (most
particularly benzene) in gasoline.
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 Gasoline is a volatile mixture of liquid hydrocarbons generally
containing small amounts of additives suitable for use as a
fuel in a spark-ignition internal combustion engine.
 Gasoline is classified by octane ratings (conventional,
oxygenated and reformulated) into three grades

 Regular gasoline
 Gasoline having an antiknock index, i.e. octane rating, greater
than or equal to 85 and less than 88.
 Mid-grade gasoline
 Gasoline having octane rating, greater than or equal to 88 and
less than or equal to 90.
 Premium gasoline
 Gasoline having octane rating greater than 90. Premium and
regular grade motor gasoline are used depending on the octane
rating.
Some of the main components of gasoline: isooctane, butane, 3-ethyltoluene, and the octane enhancer MTBE

 The various refinery streams blended to make gasoline have different
characteristics.
 Some important streams include
 straight-run gasoline
 Reformate
 catalytic cracked gasoline, or catalytic cracked naphtha
 Hydrocrackate
 Alkylate
 Isomerate
 Butane
 Additives

 Straight-run gasoline
 Referred to as naphtha, which is distilled directly from crude oil.
 Once the leading source of fuel, its low octane rating required lead
additives.
 It is low in aromatics
 cycloalkanes (naphthenes)
 no olefins (alkenes).
 Between 0 and 20 percent of this stream is pooled into the finished gasoline,
 RON, Research Octane Number is too low
 RON and (RVP) Reid Vapor Pressure are improved via:
 reforming
 isomerisation.
 However, before feeding those units, the naphtha needs to be split into light
and heavy naphtha.
 Straight-run gasoline can be also used as a feedstock into steam-crackers to
produce olefins*
www.ChemicalEngineeringGuy.com *Further Studied in Petrochemicals Course
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 Reformate
 Produced in a catalytic reformer
 Has a high octane rating:
 high aromatic content
 low olefin content.
 (BTX) are removed to some extent.
 FCC Gasoline
 catalytic cracked gasoline, or catalytic cracked naphtha
 produced with a catalytic cracker
 has a moderate octane rating
 high olefin content
 moderate aromatic content.
 Butane
 is usually blended in the gasoline pool
 the quantity of this stream is limited by the RVP specification.

 Hydrocrackate (heavy, mid and light)
 produced with a hydrocracker
 has a medium to low octane rating
 contains moderate aromatic levels.
 Alkylate
 is produced in an alkylation unit
 Feedstock are isobutane and olefins as feedstocks.
 Contains no aromatics or olefins and has a high MON
 Isomerate
 is obtained by isomerizing low-octane straight-run
gasoline into iso-paraffins
 non-chain alkanes, such as isooctane
 Has a medium RON and MON
 Does not has aromatics or olefins.

 Antiknock additives & Oxygenates
 TEL (triethyl lead)
 MTBE, ETBE, TAME
 Used to increase Octane Rating
 Fuel stabilizers (antioxidants and metal deactivators)
 Avoids gummy, sticky resin deposits result from oxidative
degradation of gasoline during long-term storage
 Deactivators: compounds that sequester (deactivate) metal
salts that otherwise accelerate the formation of gummy
residues

 Detergents
 additives that reduce internal engine carbon buildups
 improves combustion
 allows easier starting in cold climates
 Dyes
 Though gasoline is a naturally colorless liquid, many gasolines
are dyed in various colors to indicate their composition and
acceptable uses.
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 Product name : BP Premium Unleaded Petrol

 Kerosene is a light petroleum distillate that is used in:
 space heaters
 cook stoves
 water heaters
 Kerosene has:
 maximum distillation temperature of 204 °C (400 °F) at the 10% recovery
point
 final boiling point of 300 °C (572 °F)
 minimum flash point of 37.8 °C (100 °F).
 A kerosene-type jet fuel-based product will have (ASTM Specification
D1655:
 maximum distillation temperature of 204 °C (400 °F) at the 10% recovery
point
 a final maximum boiling point of 300 °C (572 °F)

 The two grades are recognized by ASTM
Specification D3699.
 Refined middle distillate suitable for use as a
fuel for heating or illuminating, the
classification of which shall be defined by ASTM
D3699
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 Aviation Gasoline (AvGas)
 It means a type of gasoline suitable to use as a fuel in
an aviation spark-ignition internal combustion engine.
 Aviation Turbine Fuel (JetFuel)
 It means a refined middle distillate suitable for to as a
fuel in an aviation gas turbine internal combustion
engine.

 ASTM Specification D1655  Jet Fuel

 The DEF STAN 91-91 (UK) and ASTM D1655 (international)
specifications allow for certain additives to be added to jet
fuel, including
 Antioxidants  to prevent gumming, usually based on alkylated
phenols
 Antistatic agents  to dissipate static electricity and prevent
sparking; Stadis 450, with dinonylnaphthylsulfonic acid (DINNSA)
 Corrosion inhibitors  DCI-4A used for civilian and military fuels

 Fuel system icing inhibitor (FSII) agents  Di-EGME
 Biocides are to remediate microbial (i.e., bacterial and fungal) growth present in aircraft fuel
systems.
 Examples are Kathon FP1.5 Microbiocide and Biobor JF.
 Metal deactivator  remediates the deleterious effects of trace metals on the thermal stability
of the fuel.

 Check out the difference between
Diesel and Gasoline Engines:
 https://www.youtube.com/watch?v=bZUoLo5t7kg
 https://www.youtube.com/watch?v=rlK7JIAz9WY
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 Liquid fuel used in diesel engines, whose fuel ignition
takes place, without any spark, as a result of
compression of the inlet air mixture and then injection of
fuel.
 Diesel engines have found broad use as a result of higher
thermodynamic efficiency and thus fuel efficiency.
 Petroleum diesel, also called petrodiesel, or fossil diesel
is the most common type of diesel fuel.
 It is produced from the fractional distillation of crude oil
between 200 °C (392 °F) and 350 °C (662 °F) at
atmospheric pressure
 The mixture of carbon chains that typically contain
between 8 and 21 carbon atoms per molecule.

 The quality of diesel fuels can be expressed as
cetane number or cetane index.
 Cetane  (C¹⁶H³⁴) which has high ignition (CN = 100)
 alpha-methylnaphthalene  (C¹¹H¹⁰) which has low
ignition quality (CN = 0).
 Diesel fuel includes:
 No.1 diesel (Super-diesel)
 cetane number of 45
 it is used in high speed engines, trucks and buses.
 No. 2 diesel
 40 cetane number
 Railroad diesel fuels
 are similar to the heavier automotive diesel fuels
 have higher boiling ranges up to 400 °C (750 °F)
 lower cetane numbers (CN = 30).

 Metal Deactivators
 Stabilizers
 Corrosion Inhibitors
 Cetane Improvers
 Cold flow Improvers
 Detergents
 Lubricity Improvers
 Dyers
 Demulsifiers
 De-icers

 What:
Gravimetric determination by filtration of particulate
contaminant in a sample of aviation turbine fuel (D5452)
and middle distillate fuel (D6217) delivered to a laboratory.
 The mass change difference during filtration identifies the
contaminant level per unit volume.
 Method D6217 using less quantities of fuel than D5452, and thus,
is a faster method to perform.

 Why:
 These test methods provides a gravimetric
measurement of the particulate matter present in a
sample of:
 aviation turbine fuels
 diesel fuels delivered
 The objective is to minimize these contaminants to
avoid filter plugging and other operational problems.
 Although tolerable levels of particulate contaminants
have not yet been established for all points in fuel
distribution systems, the total contaminant
measurement is normally of most interest.

 The mass of particulates present in a fuel is a significant factor,
along with the size and nature of the individual particles, in the
rapidity with which fuel system filters and other small orifices in
fuel systems can become plugged.
 The test methods can be used in specifications and purchase
documents as a means of controlling particulate contamination
levels in the fuels purchased.
 Maximum particulate levels are specified in several military fuel
specifications.

 How:
ASTM D5452 Standard Test Method for Particulate Contamination in Aviation Fuels
by Laboratory Filtration
 ASTM D6217 Standard Test Method for Particulate Contamination in Middle
Distillate Fuels by Laboratory Filtration

 ASTM D5452 (AVIATION FUELS)
 A known volume of fuel is filtered through a preweighed test membrane filter and the
increase in membrane filter mass is weight determined after washing and drying.
 The change in weight of a control membrane located immediately below the test
membrane filter is also determined.
 The objective of using a control membrane is to assess whether the fuel itself influences
the weight of a membrane.
 The particulate contaminant is determined from the increase in mass of the test
membrane relative to the control membrane filter.
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 ASTM D6217 (DIESEL)
 A measured volume of about 1 L of fuel is vacuum filtered through one or more sets of 0.8
µm membranes.
 Each membrane set consists of a tared nylon test membrane and a tared nylon control
membrane.
 After the filtration has been completed, the membranes are washed with solvent, dried,
and weighed.
 The particulate contamination level is determined from the increase in the mass of the
test membranes relative to the control membranes, and is reported in units of g/m3 or its
equivalent mg/L

 Alternative test methods: ASTM D7321 (diesel with FAME), EN 12662
Gasoline: Max 1 mg/l (D5452)
Jet kerosine: Max 1 mg/l (D5452)
Diesel: Max 10 mg/l (D6217)

 Refined oil middle distillates, heavy distillates, or residues of refining,
or blends of these, suitable for use as a fuel for heating or power
generation, the classification of which shall be defined by ASTM D396
 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
 No. 2 fuel oil is very similar to No. 2 diesel fuel.
 No. 3 and 4 are Heavier grades of Oils
 It is mainly composed of vacuum residue.
 Critical specifications are viscosity and sulphur content.
 Low sulphur residues are in more demand in the market.

 In the maritime field another type of classification is
used for fuel oils:
 MGO (Marine gas oil) - roughly equivalent to No. 2 fuel oil,
made from distillate only
 MDO (Marine diesel oil) - A blend of heavy gasoil that may
contain very small amounts of black refinery feed stocks,
but has a low viscosity up to 12 cSt so it need not be heated
for use in internal combustion engines
 IFO (Intermediate fuel oil) A blend of gasoil and heavy fuel
oil, with less gasoil than marine diesel oil
 MFO (Marine fuel oil) - same as HFO (just another "naming")
 HFO (Heavy fuel oil) - Pure or nearly pure residual oil,
roughly equivalent to No. 6 fuel oil

 Bunker Oil
 Grades of Bunker fuel Bunker A
 Gasoil range bunker fuel, typically called marine diesel or marine
gasoil
 Bunker B
 Low-viscosity vac-resid range bunker fuel.
 Typically cut with some lighter material (VGO) to reduce viscosity
to the point that it will flow without heating
 Bunker C
 The most common form of bunker.
 Composed primarily of vac-resid range material
 High viscosity that requires heating in order to pump.
 Typically sold at several viscosity specifications:
 180 centistoke, 380 centistoke, or 460 centistoke

 Check out why Bunker Fuel/Oil is an
environment problem:
 https://www.youtube.com/watch?v=FkopqYgZldQ
 https://www.youtube.com/watch?v=NsAYXryC3dw
 https://www.youtube.com/watch?v=TqBQExjMlCk

 Lubricants are based on the viscosity index.
 Paraffinic and naphthenic lubricants have a
finished viscosity index of more than 75.

 The lube oil base stocks are prepared from selected crude oils
by distillation and special processing to meet the desired
qualifications.
 The additives are chemicals used to give the base stocks
desirable characteristics which they lack or to enhance and
improve existing properties.
 The properties considered are:
 Viscosity
 Viscosity change with temperature (vicosity index)
 Pour point
 Oxidation resistance
 Flash point
 Boiling temperature
 Acidity (neutralization number)
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 Viscosity index is the most important characterisitics of a
lube oil.
 It is defined as the rate of change of viscosity with
temperature is expressed by the viscosity index (VI) of the
oil.
 The higher the VI, the smaller its change in viscosity for a
given change in temperature.
 The VIs of natural oils range from negative values for oils
from naphthenic crudes to about 100 for paraffinic
crudes.
 Specially processed oils and chemical additives can have
Vis of 130 and higher.

 Additives, such as polyisobutylenes and
polymethacrylic acid esters, are frequently mixed
with lube blending stocks to improve the
viscosity–temperature properties of the finished
oils.
 Lube oil blending stocks from paraffinic crude oils
have excellent thermal and oxidation stability
and exhibit lower acidities than do oils from
naphthenic crude oils.
 The neutralization number is used as the measure
of the organic acidity of an oil; the higher the
number, the greater the acidity.

 Go to: https://www.airport-suppliers.com/supplier/shell-aviation/
 Verify types of product and main content.

 is a sticky, black, and highly viscous liquid or semi-solid
form of petroleum.
 natural deposits
 refined product
 The primary use (70%) of asphalt is:
 in road construction
 glue or binder  reate asphalt concrete.
 bituminous waterproofing products
 Roofing felt and for sealing flat roofs

 The components of asphalt include four main classes of
compounds:
 Naphthene aromatics (naphthalene)
 partially hydrogenated polycyclic aromatic compounds
 Polar aromatics
 high molecular weight phenols
 carboxylic acids produced by partial oxidation of the material
 Saturated hydrocarbons
 percentage of saturated  softening point
 Asphaltenes
 high molecular weight phenols
 heterocyclic compounds

 Viscosity Grade Bitumen (Asphalt) is a Bitumen grade
mostly used as a Paving Grade and it’s suitable for road
construction and for the asphalt pavements producing
with premier attributes.
 VG Bitumen is usually used in the production of hot mix
asphalt.
 Asphalt is an important product in the construction
industry and comprises up to 20% of products.
 It can be produced only from crude containing
asphaltenic material.

 Softening point
 is the temperature at which a material softens
beyond some arbitrary softness.
 It can be determined, for example, by the Vicat
method, Heat Deflection Test or a ring and ball
method
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 Penetration 
 Penetration value test on bitumen is a measure of hardness or
consistency of bituminous material.
 A 80/100 grade bitumen indicates that its penetration value lies
between 80 & 100.

 Check out this penetration test of Asphalt:
 https://www.youtube.com/watch?v=aGIwl6h4SaU
 https://www.youtube.com/watch?v=HQH5Wf07tRk

 Carbon compounds formed from thermal conversion of
petroleum containing resins and asphaltenes are called
petroleum cokes.
 There are at least four basic types of petroleum coke,
namely
 needle coke
 honeycomb coke
 sponge coke
 shot coke.
 Fuel grade coke contains about 85% carbon and 4%
hydrogen.
 The balance is made up of sulphur, nitrogen, oxygen,
vanadium and nickel.

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