CRUDE CLASSIFICATION

&

PRODUCT SPECIFICATIONS

CRUDE CLASSIFICATION & PRODUCT SPECS

OVERVIEW OF PRESENTATION

CRUDE OIL

CLASSIFCATION OF CRUDE

SIGNIFICANCE OF ‘TESTS’

PRODUCT SPECIFICATION

CRUDE OIL

Petroleum : Petra – Rock, Oleum – Oil. Black Gold Crude oil is a substance, generally

liquid, occurring naturally in the earth and composed mainly of mixtures of chemical compounds of Carbon and Hydrogen with or without other nonmetallic elements such as Sulfur, Oxygen, and Nitrogen

Crude OilComplex mixture of thousands of chemical compounds that are mostly composed of Carbon and Hydrogen (called Hydrocarbons) ranging from one to 90 carbon atoms

Contains small amount of Sulphur (upto 5 %)Oxygen (upto 5 %)Nitrogen (upto 1 %)Metals (upto 0.1 %)

Most of the above are chemically combined with carbon and hydrogen and treated as impurities and contaminant

CRUDE OIL

COMPOSITION :-

Parafinic NapthenicAromatic

AVERAGE OF CRUDE OIL COMPOSITION :-

Carbon : 84%Hydrogen : 14%Sulfur : 1 - 3%Remaining : 1%(Nitrogen, Oxygen& Metal salts)

Source: BP Stats 2006

CLASSIFCATION OF CRUDE OILS

Sulfur• Sweet : S < 0.5%•Intermediate : 0.5% < S < 1.0%•Sour : 1.0% < S < 2.0%•Highly Sour : S >2.0% ACIDITY

Low Acidicty : TAN < 0.5High Acidity : TAN > 1.0

CRUDE OIL CHARACTERISTICS

Crude density is commonly measured by API gravityAPI gravity provides a relative measure of crude oil density …

the higher the API number, the lighter the crude.

Classified as light, medium or heavy Light crude are easier to process Heavy crude are more difficult to process

Sulfur content measures if a crude is sweet ( low sulfur) or sour ( higher sulfur)

Less than 0.5% sulfur content = sweet

Greater than 1.0% sulfur content = sour

High sulfur crude require additional processing to meet regulatory specs.

Acid content measured by Total Acid Number (TAN)

Acidic crude highly corrosive to refinery equipment.

High acid crude are those with TAN > 0.7

BENCH MARK CRUDES

• BRENT : North Sea

• West Texas Intermediate : North America

• Dubai : Middle East flowing to Asia Pacific region

• Tapis : Malaysian - Lt. Far East Oils

•Minas : Indonesian – Hy. Far East oils

• OPEC Reference Basket : A weighted average of oil blends of various OPEC countries.

API GRAVITY

Definition:- It is a measure of the weight of hydrocarbons according to a scale established by the American Petroleum Institute.

141.5API gravity = ---------------------------- - 131.5

Specific gravity at 600F

Significance :- This is used widely to classify the type of crude.

The Total Acid Number is the amount of Potassium Hydroxide in milligrams that is needed to neutralize the acids in one gram of oil. It is an important quality measurement of Crude oil.

Significance :

The TAN value indicates to the crude oil refinery the potential of corrosion problems.

 

TOTAL ACID NUMBER

Factors affecting crude selectionChoice of crude oil for a refinery depends

on many factors: Product mix Product quality Refinery configuration Product treatment facilities Refinery design spec- Metallurgy, desalter etc Environment stipulation for pollution control

For inland refinery, even pipeline design plays a role

PRODUCT SPECIFICATIONS

WHAT IS PRODUCT SPECIFICATION?THE REQUIREMENT THAT THE PRODUCT HAS TO MEET

MAY BE TECHNICAL (FUNCTIONAL / HANDLING

REQUIREMENT) OR ECOLOGICAL.

THE REQUIREMENT IS SPECIFIED AS A ‘STANDARD’ SET OF

QUALITY PARAMETERS WITH SPECIFIC QUANTITATIVE

VALUE.

THE SET OF QUANTIFIABLE QUALITY PARAMETERS IS

TERMED AS ‘SPECIFICATION’

PRODUCT IS SUBJECTED TO ‘TESTS’ TO CHECK ITS

COMPLIANCE TO THE QUALITY SPECS

EXAMPLES OF QUALITY PARAMETERS ARE DENSITY,

SMOKE POINT, OCTANE NUMBER, CETANE NUMBER

WHY SPECIFICATIONS?EACH QUALITY PARAMETER IN A SPECIFICATION HAS A SIGNIFICANCE

IT EITHER IMPROVES PERFORMANCE (OF ENGINE AS IN OCTANE & CETANE NUMBER) OR ENHANCES SAFETY (AS IN FLASH POINT), HANDLYING (AS IN POUR POINT) OR REDUCES POLLUTION (AS IN SULPHUR CONTENT, BENZENE CONTENT)

SPECIFICATION BECOMES MORE STRINGENT WITH ADVANCEMENT OF TIME, TECHNOLOGY & CUSTOMER / SOCIAL DEMANDS.

STANDARD QUALITY CONTROL PARAMETERS

FOLLOWING ARE SOME PROMINENT QUALITY CONTROL PARAMETERS:

DENSITY DISTILLATION RANGE FLASH POINT FIRE POINT OCTANE NUMBER CETANE NUMBER DIESEL INDEX SULFUR CONTENT SMOKE POINT POUR POINT

PRODUCT BLENDING IS CONTROLED TO ENSURE COMPLIANCE TO PRODUCT SPECIFICATION.

FLASH POINT

Definition :- The flash point of a fuel is the lowest temperature at which the application of a flame causes the vapour above the sample to ignite.

Significance

It is important primarily from a fuel-handling standpoint. Too low a flash point will cause fuel to be a fire hazard. A low-flash point may indicate contamination by more volatile and explosive fuels / fractions. Flash point (BIS) requirements for some petroleum products are:

S.K.O - 350 C U.L.S.H.S.D. - 350 CH.S.D - 350 CF.O. - 660C A.T.F - 380 C

FIRE POINT

Definition :-  Fire point is the lowest temperature, corrected to one atmosphere pressure at which the application of a test flame to the oil sample surface causes the vapour of the oil to ignite and burn for 5 secs. Significance :-

Low fire point petroleum products are potential fire hazards.  

SMOKE POINT

Definition :-  It is defined as the maximum height of flame in millimeters at which the given oil will burn without giving smoke in a standard lamp under specified conditions.  Significance :-  Smoke point is an indication of clean burning quality of kerosene.

In India, marketable kerosene should possess a smoke point of 18mm. 

ANILINE POINT

Definition :- Aniline point is the lowest temperature at which oil is completely miscible with an equal volume of Aniline.  Significance:- High aniline point indicates that the fuel is highly paraffinic and hence has a high Diesel index and very good ignition quality. In case of aromatics the aniline point is low and the ignition quality is poor. This test is useful for calculating Diesel Index.

 

DIESEL INDEX

Definition :- Diesel index is a measure of ignition quality of fuel. Diesel Index = (Aniline Point in oF X oAPI) -----------------------------

100Significance :- High Diesel index indicates better ignition quality. Used as a guide in the absence of an engine for testing Cetane No.

CETANE NUMBER

Definition :-

This is a measure of the tendency of diesel fuels to knock in a diesel engine.

It is determined  in a single cylinder CFR engine by comparing the ignition delay characteristics of the fuel with that of the reference blends of known Cetane no.

Reference fuels : Normal Cetane – 100 Heptamethyle nonane 15

Significance :- It is the index of ignition quality of a fuel. High cetane number fuel will enhance easy starting of compression ignition engines and lessen engine roughness.

OCTANE NUMBER

 Definition :- 

It is defined as percentage volume of Iso-octane in a mixture of Iso-octane and n-heptane that gives the same knocking characteristic as the fuel under consideration.

Reference fuel : iso –Octane – 100 n-Heptane - 0

Significance :-  High Octane number reduces knocking in a petrol engine and improves engine life.

OXYGENATES IN GASOLINE

Definition :-

Motor gasoline, having oxygen content of 2.7 percent or higher by weight is known as Oxygenated Gasoline.  Significance :- Oxygenated gasoline helps engines run leaner, which helps engines, particularly older engines, produce less carbon monoxide. Common oxygenates are MTBE (Methyl Tertiary Butyl Ether) & Ethanol.

CLOUD POINT

Definition :- Cloud point is the temperature at which a cloud or haze of wax crystals appears at the bottom of the test jar when the oil is cooled under the prescribed conditions.  

Significance :- It indicates the temperature above which oil can be safely handled without any fear of congealing or filter clogging.

POUR POINT

Definition :- Pour point is the lowest temperature in multiples of 3 Deg. C at which the oil will just flow when cooled under prescribed conditions.  Significance :- It indicates the pumpability of the fuel and it indicates the waxy nature of the fuel.

  Unit Value

Total volatile sulfur ppmwt 200 max.

Evaporation temperature for 95 vol%

°C 2 max.

Vapor pressure @ 40 °C kPa 1050 max.

Mercaptan sulfur ppmwt 50-150

Hydrogen sulfide ppmwt Nil

Free water ppmwt Nil

LPG

  Unit Value

Paraffins vol% 65 min.

Aromatics vol% 10 max.

Olefins vol% 1 max.

Density kg/m³ Free

IBP °C 34 min.

FBP °C 160 max.

Sulfur wt% 0.15 max.

RVP @ 38 °C psi 10 max.

NAPHTHA

    EURO III EURO IV

    Premium Regular Premium Regular

  Unit Value Value Value Value

RON unleaded - 95 min. 91 min. 95 min. 91 min.

MON unleaded - 85 min. 81 min. 85 min. 81 min.

Density kg/m³ 720-775 720-775 720-775 720-775

Evaporation at 70 °C

vol% 10-45 10-45 10-45 10-45

Motor Spirit

 

  

    EURO III EURO IV

    Premium Domestic Premium Domestic

Evaporation at 100 °C

vol% 40-70 40-70 40-70 40-70

Evaporation at 150 °C

vol% 75 min. 75 min. 75 min. 75 min.

Final Boiling Point

°C 210 max. 210 max. 210 max. 210 max.

Sulfur wt% 0.015 max.

0.015 max.

0.005 max.

0.005 max.

 

Motor Spirit

    EURO III EURO IV

    Premium Domestic Premium Domestic

RVP @ 38°C kPa 60 max. 60 max. 60 max. 60 max.

Benzene vol% 1 max. 1 max. 1 max. 1 max.

Aromatics vol% 42 max. 42 max. 35 max. 35 max.

Oxygen content

wt% 2.7 max. 2.7 max. 2.7 max. 2.7 max.

Oxidation stability

mints 360 min. 360 min. 360 min. 360 min.

Olefin content vol% 18 max. 21 max. 18 max. 21 max.

Motor Spirit

  Unit Value

Density @ 15 °C kg/m³ 775-840

Smoke point mm 19 min.

Freezing point °C - 47 max.

Color Saybolt - +10 min.

Distillation, 10 vol% °C 205 max.

Distillation, FBP °C 300 max.

Copper Strip Corrosion, 3 hrs @ 50 °C - Not worse than No.1

JET FUEL

 

  Unit Value

Sulfur wt% 0.25 max.

Flash point °C 38 min.

Viscosity @ -20 °C mm2/s 8.0 max

Naphthalene content vol% 3.0 max.

Silver Strip Corrosion, 16 hrs @ 45 °C - 0 max.

Thermal stability (JFTOT) mm Hg 25 max.

Water Separation Index Modified (WSIM)

- 70 min.

JET FUEL

    EURO III EURO IV

  Unit Value Value

Density @ 15 °C kg/m³ 820-845 820-845

Cetane Index min. 46 48

Cetane Number (Note 1) min. 51 51

CFPP, Winter / Summer °C, max. 6 / 18 6 / 18

Water content vol%max

0.02 0.02

Distillation, 85 vol% °C max 350 350

DIESEL

Distillation, 95 vol% °C 360 max. 360 max.

Viscosity @ 40 °C cSt 2 – 4.5 2 – 4.5

Sulfur ppm max.

350 50

Flash point °C min. 35 35

Polycyclic Aromatic Hydrocarbons (PAH)

wt% max. 11 11

Lubricity @ 60 °C microns max.

460 460

Copper Strip Corrosion, 3 hrs @ 50 °C

- No. 1 No. 1

DIESEL

    Regular Fuel Oil

Plant Fuel Oil

  Unit Value Value

Density @ 15 °C kg/m³ free free

Flash point °C min.

66 66

Pour point (Note 1) °Cmax.

27 -

Kinematic Viscosity @ 50 °C cStmax.

180 8,500-50,000

Sulfur wt%max.

4.0 1.8

FUEL OIL

CRUDE OIL CLASSIFICATION

Definition :-

Based on the predominant proportion of similar Hydrocarbon molecules, crude oils are classified based on API gravity / density and sulfur content. Crude oils are also classified based on quality of Hydrocarbon Sulfur and other reactive Sulfur components.

Crude oil with less Sulfur is called “SWEET”

Crude oil with more Sulfur is called “SOUR”

India - Oil & Gas Resources

Crude Oil Reserves: 786 mtoe/5.9 bln bbl (end 2005)Production: 36.2 mln ton/816 tbpd (2005)

Natural GasReserves: 1101 bcm (end 2005)Production: 30.4 bcm (2005)

Source: BP Stats 2006

WHAT IS A PETROLEUM PRODUCT ?

A PRODUCT IS SOMETHING THAT SATISFIES A NEED & CONSEQUENTLY HAS ECONOMIC VALUE

PETROLEUM PRODUCT IS AN ENGINEERED MATERIAL THAT MEETS THE REQUIREMENT

A PETROLEUM PRODUCT EX. GASOLINE, DIESEL, LPG IS A HOMOGENEOUS MIXTURE OF PETROLEUM FRACTIONS THAT IS BLENDED IN A CONTROLLED MANNER TO MEET THE REQUIREMENT

HISTORY OF REFINING

Year

Process name

Purpose

By-products, etc.

1862 Atmospheric distillation Produce kerosene Naphtha, tar, etc.

1870 Vacuum distillation Lubricants (original) Cracking feedstocks (1930's)

Asphalt, residual coker feedstocks

1913 Thermal cracking Increase gasoline Residual, bunker fuel

1916 Sweetening reduce sulfur & odor Sulfur

1930 Thermal reforming Improve octane number Residual

1932 Hydrogenation Remove sulfur Sulfur

1932 Coking Produce gasoline basestocks Coke

1933 Solvent extraction Improve lubricant viscosity index

Aromatics

1935 Solvent dewaxing Improve pour point Waxes

1935 Cat. Polymerization Improve gasoline yield & octane number

Petrochemical feedstocks

1937 Catalytic cracking Higher octane gasoline Petrochemical feedstocks

1939 Visbreaking reduce viscosity Increased distillate,tar

HISTORY OF REFINING

Year

Process name

Purpose

By-products, etc.

1940 Alkylation Increase gasoline octane & yield

High-octane aviation gasoline

1940 Isomerization Produce alkylation feedstock Naphtha

1942 Fluid catalytic cracking Increase gasoline yield & octane

Petrochemical feedstocks

1950 Deasphalting Increase cracking feedstock Asphalt

1952 Catalytic reforming Convert low-quality naphtha Aromatics

1954 Hydrodesulfurization Remove sulfur Sulfur

1956 Inhibitor sweetening Remove mercaptan Disulfides

1957 Catalytic isomerisation Convert to molecules with high octane number

Alkylation feedstocks

1960 Hydrocracking Improve quality and reduce sulfur

Alkylation feedstocks

1974 Catalytic dewaxing Improve pour point Wax

1975 Residual hydrocracking Increase gasoline yield from residual

Heavy residuals

TYPICAL APPROXIMATE CHARACTERISTICS AND PROPERTIES AND GASOLINE POTENTIAL OF VARIOUS CRUDES

(Representative average numbers)

Crude source

Paraffins (% vol)

Aromatics (% vol)

Naphthenes (% vol)

Sulfur (% wt)

API gravity

(approx.)

Napht. yield (% vol)

Octane no

(typical)

Nigerian -Light

37 9 54 0.2 36 28 60

Saudi -Light

63 19 18 2 34 22 40

Saudi -Heavy

60 15 25 2.1 28 23 35

Venezuela -Heavy

35 12 53 2.3 30 2 60

Venezuela -Light

52 14 34 1.5 24 18 50

USA -Midcont. Sweet

- - - 0.4 40 - -

USA -W. Texas Sour

46 22 32 1.9 32 33 55

North Sea -Brent

50 16 34 0.4 37 31 50

TYPICAL ALKENES.

Simplest Alkene (C2H4):

Typical Alkenes with the same chemical formula (C4H8) but different molecular structures:

ETHYLENE (C2H4) 1-BUTENE (C4H8) ISOBUTENE (C4H8)

TYPICAL APPROXIMATE CHARACTERISTICS AND PROPERTIES AND GASOLINE POTENTIAL OF VARIOUS CRUDES

(Representative average numbers)

Crude source

Paraffins (% vol)

Aromatics (% vol)

Naphthenes (% vol)

Sulfur (% wt)

API gravity

(approx.)

Napht. yield

(% vol)

Octane no

(typical)

Nigerian Light 37 9 54 0.2 36 28 60

Saudi Light 63 19 18 2 34 22 40

Saudi Heavy 60 15 25 2.1 28 23 35

Venezuela Heavy 35 12 53 2.3 30 2 60

Venezuela Light 52 14 34 1.5 24 18 50

USA Midcont. Sweet

- - - 0.4 40 - -

USA-W. Texas Sour

46 22 32 1.9 32 33 55

North Sea Brent 50 16 34 0.4 37 31 50

CRUDE INPUT CONSISTS OF

INDIGENOUS CRUDE ASSAM & NORTH /SOUTH GUJRAT ARE MAIN

ONSHORE CRUDES. BOMBAY HIGH, RAVVA, PANNA MUKTA ARE MAIN

OFF-SHORE CRUDE. SUPPLY IS LOWER THAN REQUIREMENT CHEAPER COMPARED TO IMPORTED CRUDE DUE

TO DUTY/TAX AND FREIGHT ADVANTAGE .

IMPORTED CRUDE HIGH SULPHUR LOW SULPHUR

TYPICAL AROMATICS. Example of simple aromatic compound: Examples of simple double-ring aromatic

compound:

BENZENE (C6H6) NAPTHALENE (C10H8)

SOURCING OF CRUDE OIL

• INDIGENOUS CRUDE• MAINLY BASED ON GOVT.,

ALLOCATION

• IMPORTED CRUDE• TERM CONTRACT

• TERM TENDER

• SPOT TENDER

CRUDE OILGRADATION OF CRUDE OIL

BASED ON PRODUCTION CAPABILITY OF PARTICULAR PRODUCT

BITUMENIOUS (BASRA, KUWAIT, AM) NON-BITUMENIOUS HIGH SULFUR (INDIAN,

MALAYSIAN, OMAN) LUBE (AM, BASRA,MURBAN) NON LUBE (KUWAIT,MASILA) ATF NON-ATF

Key features with indigenous crude

LPG, Naphtha will be on spec

SKO ex-Assam crude would need de-aromatisation / hydro treatment for improvement of smoke point

Diesel ex-Assam crude requires hydrotreating or addition of cetane improver.

Mostly non-ATF (excepting Gujarat crudes)

Non-Bituminous, therefore all residue converted to LSHS

CRUDE OIL

GRADATION OF CRUDE OIL BASED ON SULFUR CONTENT

LOW SULFUR ,Sulfur , <0.5 %wt ( INDIAN, MALAYSIAN, WAF) HIGH SULFUR , Sulfur , >0.5 %wt (LATIN AMERICAN, PG)

BASED ON API GRAVITY LIGHER, API>30( INDIAN, MALAYSIAN, WAF) HEAVIER API<30 (LATIN AMERICAN, PG)

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