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Petroleum RefiningChapter 5: Refinery Feeds and Products
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Refinery Feeds and Products
Refinery Feeds
1. Kuwait crude mix: (To all refineries)
Crude % API Sulfur, wt%
Kuwait Export Crude
Ratawi
Brugan
95
4.24
0.76
31.4
23.5
23.4
2.56
3.77
3.32
Total 100 31 2.62
From the divided area between Kuwait and Saudi Arabia.
2. Eocene: (To MAA Refinery)
3. Natural Gas: (To all refineries)
Destination Source Description Flow Rate
MAA KOC west fields Sour gas
Sour condensate
210 MMSCFD
40 MBPSD
SHB Burgan gas Sour gas 48.7 MMSCFD
MAB 39 MMSCFD
Refinery Products
There are 2000 products (Refineries & Petrochemical plants)
Storage is expensive & limited products must be sold or used.
The price of refinery products is influenced by
1. Location
2.
Demand
3. Availability
4.
Combustion characteristics
5. API
6.
Sulfur content
7.
Prices of competing fuels Usually the lowest value of a HC product is determined by its heating value or fuel oil
equivalent (FOE).
Combustion characteristics are determined by octane number for gasoline and cetane
number for Diesel.
Example of refinery products are shown below
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Table 5.1. Refinery Main Products and their uses.
Products Main Use
1. Fuel Gas (mainly C1 & C2) Used within the refinery for to fuel heaters, boilers,
etc.
2. LPG (mainly C3 & C4) For export and local consumption
3. Gasoline Motor, Aviation, tractor, marine4. KNG (Kuwait Natural Gasoline) Motor
5. Kerosene Aviation Turbine Kerosene (ATK)
Illuminating Kerosene (IK)
Dual Purpose Kerosene (DPK)
Gas turbine or jet fuel (JP5/8/9)
6. Diesel HSD (Auto Engines)
Marine Diesel Oil (Slow Engines)
Low Pour Point Diesel
7. EGO (Export GO) (Heavier than diesel) used for fuel or further
processing
8. Heating oil Heating
9. Fuel oil LSFOlow sulfur fuel oil (for water desalination
& power and plants)
HSFO - High sulfur fuel (Bitumen)
LFO (Bunker/Cargo)
14. Sulfur Sulfuric acid, matches, etc.
15.
16.
Coke (carbon)
Asphalts
Aluminum and other industries
Roads
17. Oils and waxes Lubricating oils
White oils
Transformer & cable oilsGreases
Waxes
18. Chemicals, Solvents, misc. Many industries
Table 5.2. Applicable ASTM Specifications for Petroleum Products
Specification for Specification Number
1. LPG D1835
2. Automotive Gasoline D439
3. Aviation Gasoline D910
4. Aviation Turbine Fuels D16555. Fuel Oil no. 1 to 6 D396
6. Diesel Fuel Oil D975
7. Gas Turbine Fuel Oil D2880
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Table 5.3. Kuwait Refineries Feeds and Products.
MAA refinery
(400 MBPD)
SHB refinery
(200 MBPD)
MAB refinery
(265 MPD)
Product BPD Product BPD Product BPD
Propane
ButanePentane
LPG LPG
KNG (Kuwait Natural
Gasoline)
MoGas (96 unleaded,
90, 95 , 98 Leaded)
Gasoline
light Naphtha
Naphtha
PCN
Naphtha
PCN
lt Naphtha
Hvy Naphtha
PCN
Alkylate
ATK
DPK
JP8
Kerosene
Kerosene ATK
ILL Kerosene
High Speed Diesel (HSD)
Marine Diesel Oil
Diesel
Marine Diesel
Low Pour Point
Diesel
HSD 20P/30P
Marine Diesel
Oil
Export GO EGO (Export
GO)
VGOCGO
LSFO
LFO (Bunker)
HFO (Bunker/Cargo)
Bitumen
Fuel Oil Fuel Oil
Sulfur Sulfur Sulfur 228.3
Bitumen Coke 710.6M tons/yr
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Physical and Chemical Properties of Refinery Products
Low Boiling Products
Compounds that are in gas phase at ambient T & P.
Examples; methane, ethane, propane, butane, and their olefins.
Require a gas plant in the refinery Gas quantity is expressed in
1. Weight basis: (lb or kg)
2. Volumetric basis: scf (standard cubic feet) or Nm (normal cubic meters)
3. Heating Value: (bbls FOE based on a lower heating value LHV of 6.05 MMBtu
or 6.38X106KJ).
Standard conditions 60 F & 14.7 psia
Example 5.1:Calculate the mass flow rate and the fuel oil equivalent (FOE) for a gas stream flowing at
10 MMSCFH. The laboratory analysis of the gas is given below,
Vol %C1 70
C2 25
C3 5
Solution:For a gas at standard conditions (ideal), the volume percent is equal to the mole percent.
mole % MW heating value (Btu/scf)
C1 70 16 909.4
C2 25 30 1618.7
C3 5 44 2314.9
PV = nRT
n = PV/RT = (14.71E+7)/(10.73(60+460)) = 26,346 lbmol/hror simply divide by 379.5 such that 1E+7/379.5 = 26,350 lbmole/hr
Mole average the MW of gas = 0.716 + 0.2530 + 0.0544
= 20.9 lbm/lbmol
gas mass flow = 26,35020.9 = 550,712 lbm/hr
Vol. average heating value = 0.7909.4 + 0.251618.7 + 0.052314.9
= 1157 Btu/scf
Gas heating value = (1E+7) SCFH (1157) Btu/scf = 1.157E+10 Btu/hr
FOE = (1.157E+10) Btu/hr / (6 MMBtu/bbl) = 1930 bbl/hr = 46,300 BPD
Table 5.4: Properties of Hydrocarbons and common gases1
Compound MW
Heating Value
60F, 1 atm (Btu/scf)
Net Gross
Methane
Ethane
Propane
i-Butane
n-Butane
i-Pentane
n-Pentane
n-Hexane
16.043
30.070
44.097
58.123
58.123
72.150
72.150
86.177
909.4
1618.7
2314.9
3000.4
3010.8
3699.0
3706.9
4403.8
1010.0
1769.6
2516.1
3251.9
3262.3
4000.9
4008.9
4755.9
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n-Heptane
n-Octane
n-Decane
Hydrogen sulfide
Nitrogen
OxygenCarbon Dioxide
Water
Air
100.204
114.231
142.285
34.080
28.013
31.99944.010
18.0153
28.9625
5100.8
5796.1
7189.6
586.8
-
--
-
-
5502.5
6248.9
7742.9
637.1
-
--
-
-1Source GPSA Engineering Data Book, 10thed., 1987.
1. Methane (C1)
Use: - Refinery fuel (burned in heaters).
- Feedstock to the H2production unit.
2. Ethane (C2)
Use: - Refinery fuel.
-
Feedstock to H2production unit.
- Feedstock to produce ethylene (petrochemical plant).
3. Propane (C3)
Use: - Refinery fuel
- Sold as LPG
- Propylene is sometimes separated for sale to petrochemical plants for
polypropylene manufacture.
4. n-Butane (n-C4):
Use: - Sold as LPG
- Feedstock to isomerization units producing isobutane.
-
Blending into Gasoline (increase octane number1
). Price of gasoline > LPG
It is better to blend n-C4 into gasoline than sell it as LPG
It has high Octane Number (in the 90s)
VP (n-C4) < VP (i-C4)
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5. Iso-butane (i-C4)
i-C4can also be blended into gasoline, but its relatively higher RVP permits a lesser
amount to be incorporated into gasoline than n-butane.
Has greatest value when used as feedstock to alkylation unit.
i-C4 +
Propene
ButenesPentenes
alkylation iso-paraffins (high octane)in the gasoline boiling range
LPG
Liquefied petroleum gas contains mostly C3and C4with various ratios.
Produced from almost all processing units with naphtha stabilizers or debutanizers.
Gasoline
Motor gasoline is the principal product of refineries.
It consists of a complex mixture of HCs with typical ASTM BP range from 100 to
400 F. API survey shows
- 40 types of gasoline exist
(variations in octane number, API, IBP, FBP, ).
- 90 % of gasoline in US used as motor fuel.
Gasoline Types: - leaded - unleaded
Grades
Kuwait UAE KSA USA
Regular
Premium
Super Premium
Utra
-
91
95
98
-
99
87
89
92/93
Regular Leaded Gasoline in US is now used only for:
- Farm equipment. - Pre 1972 automobiles.
The difference is inAntiknock performance
Octane Number
Is a measure of the degree of knocking of (gasoline).
It compares the degree of combustion of gasoline to that of a mixture of n-heptane
(zero octane) and iso-octane (100 octane) expressed as V% iso-octane (2,2,4-
trimethylpentane) .
Most common lab tests for determination of octane number:(a)Motor method (MON)
Represent performance on the highway or heavy load conditions (high speed).
(b)Research method (RON)
Represent performance during city driving (low speed and acceleration is
relatively frequent)
Both use same test engine but operate under different conditions. MON at high
engine speed and RON at low engine speed.
(c)
Posted octane number (PON)2
RON MONPON
Sensitivity of the fuelSensitivity = (RONMON)
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The sensitivity of the performance of the fuel to the two types of driving conditions
(Low Sensitivity fuels are better; equal performance is all conditions is desirable).
For all gasoline, octane numbers average about two numbers lower for the higherelevations of the rocky-mountain states
Less n-C4 can be blended because of the lower pressure at high elevations (so the
final RVP of the blend is constant). Gasoline blending streams
1. Light straight run (LSR) gasoline (C5180/190/200 F).
2.
Reformate (Catalytic Reformer gasoline).
3. Alkylate (Alkylation unit gasoline)
4.
Catalytic Cracker gasoline.
5. Hydrocracker gasoline.
6.
Polymer gasoline. (polymerizing olefins to produce higher MW olefins in the
gasoline boiling range)
7. n-C4 RVP & ON
Octane Improvers (oxygenates)1.
TEL (Tetra ethyl lead ) (pollutant)
2. MTBE (methyl tertiary butyl ether)
3. ETBE (ethyl tertiary butyl ether)
4. TAME (tertiary amyl methyl ether)
5. Ethanol
Table 5.1: Oxygenates and octane improvers of gasoline.
Methanol
Ethanol
(ethyl alcohol)
TBA
(t-Butyl Alcohol)
tert-Butanol
MTBE
(tert-butyl methyl ether)
ETBE
ethyl tert-butyl ether
TAME
tert-amyl methyl ether
TEL
(Tetraethyl lead)
Motor Gasoline Blending
1. Promote high antiknock quality (high ON).
2. Ease at starting.
3. Quick warm up.
4. Reduce vapor-lock.
5. Reduce engine deposits.
Other additives (antiknock chemicals)
1. Antioxidants.
2. Metal deactivators.3. Anti-stall agents.
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Environmental restrictions
Limit sulfur & total aromatics content of diesel.
On gasoline limit.
1. Sulfur (< 300 ppm or .03 wt %)
2.
Total aromatics
3.
Olefins24. RVP
5. Min. O2content (for areas of CO2problem)
6. Specific compounds (e.g. Benzene, xylenes)
This lead to the concept ofReformulated gasoline(a fuel for spark ignition engines
which is at least as clean burning as high methanol content fuels).
Gasoline Specifications
Properties of gasoline that have the greatest effect on engine performance:
1. RVP (govern ease of starting an engine).
2. BP. Range (IBP govern ease of starting).
3.
Anti Knock Characteristics (Octane number).
The boiling range governs
- Ease of starting
- Rate of acceleration
- Mileage economy
- Tendency toward vapor lock
- Engine warm-up time3
Warm-up time is expressed in terms the distance operated to develop full power
without excessive use of the choke (3-7 km warm-up is considered satisfactory).
Reid Vapor Pressure Vapor lock is directly related to RVP of the gasoline
The RVP should not exceed the following limits.
Ambient temp (F) Max allowable RVP (psia)
60
70
80
90
12.7
11.0
9.4
8.0
As T increases, max allowable RVP is decreased. Why?
Effect of Altitude on Gasoline
1.
Losses by evaporation.
2. Octane requirement. ( 3 units lower per 1000 ft of elevation)
In practice; the spark is advanced at higher elevation to improve engine
performance (2 units lower per 5000 ft elevation)
2React with compounds in the atmosphere producing visual pollutants.
3Controlled by the vol. % distilled @ 158 F and the 90% ASTM distillation temperature.
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Effect of hydrotreating on gasoline
Hydrotreating the FCC Naphtha (gasoline) saturates the olefins and lowers ON by 2-
3).
Table 5.5. Effects of variables on octane requirements1.
Variable Effect on Octane RequirementAltitude
Humidity
Engine speed
Air temperature
Spark advance
Coolant temperature
Combustion chamber deposits
-3 RON per 1,000 ft increase in altitude.
-1 RON per 20% increase in relative humidity @ 70 F
-1 RON per 300 rpm increase
+1 RON per 20 F rise
+1.5 RON per 1 advance
+1 RON per 10 F
+1 to 2 RON per 1,000 miles up to 6,000 miles1 Source 'Petroleum Refining Engineering', Gary & Handwerk, 1991.
Distillate Fuels
Divided into Three types:
- Jet (turbine) fuels
-
Diesel fuels
- Heating Oils (fuels)
They are blended from a variety of refinery steams to meet the desired spec.
Heating oils rank second after gasoline in refinery production
However, recently restricted by:
1. Environmental regulations on fuel emissions which caused some users to
convert to natural gas & LPG.
2.
Expansion of air & truck travel, which increased diesel & jet fuel demands.
1. Jet Fuels (Turbine Fuels)
In the kerosene boiling range
Must be clean burning.
- Commercial aviation
- Military air crafts
Limiting specifications for jet fuels in general are:
-
Freezing point (- 40 C)
- Flash point (110-150 F)
- Distillation
-
Smoke point- Aromatics content
Main difference is in freezing point - 40 to -50 C max.
Naphtha Jet Fuel
Produced primarily for the military
Wide-boiling-range stock (extends through the gasoline & kerosene boiling ranges)
More volatile & has more safety problems in handling.
Used in national emergency when kerosene type is not enough.
Kerosene Jet Fuel More safe in handling
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Commercial aviation
Narrow-boiling-range stock (350-550 F) kerosene range.
Table 5.6. US military jet fuel and related specifications.1
Specification First
Issued
Grade Type Use
AN-F-32
MIL-F-5616AN-F-34AN-F-58MIL-F-5624MIL-T-5624MIL-T-5624MIL-F-25524MIL-F-25656MIL-T-38219
MIL-T-83133
MIL-F-5161MIL-F-5572MIL-I-25017MIL-F-25558
MIL-P-25576MIL-I-27686MIL-F-81912MIL-F-82522
MIL-I-85470MIL-P-87107MIL-P-87107
1944
195019451947195019501950
19561965
1976
JP-1
JP-2JP-3
JP-4JP-5
JP-TSJP-6JP-7
JP-8
Avgas
RJ-1
RP-1FSII
RJ-4RJ-5
RJ-6FSIIJP-9JP-10
Very low-freeze kerosene
Wide cut (RVP max 2 psi)Wide cut (RVP 3 to 7 psi)
Wide cut RVP 2 to 3 psi)High-flash keroseneThermally stable keroseneLight kerosene(thermally stable)Low-volatility kerosene(special properties)
kerosene (Jet A-1 type)
RELATED SPECIFICATIONS
Referee JP-4 and JP-5Aviation gasoline(several grades)Chemical materialsHigh-density kerosene
Narrow-cut keroseneEthylene glycol mono-methyl etherhigh flash, narrow-cut keroseneT-H, dimethyl cyclopentadienesT-H Norbornadiene dimer
63% RJ-5, 37% JP-10di-EGMEblend of MCH, JP-10, and RJ-5T-H dicyclopentadiene
Obsolete
ObsoleteObsolete
Air force standardNaval carrier aircraftFlight test fuel supersonic bombers(obsolete)Very high performance aircraft
Air force standard
Ground test fuels (obsolete)Military standard (see Table 1)Fuel soluble corrosion inhibitorAir force ramjet fuel
Rocket fuelFuel system icing inhibitorMissile fuel (navy)Ramjet fuel (navy)Missile fuel
Missile fuel system icing inhibitorMissile fuelPropellant/fuel component
1Source 'ASTM manual on significance of tests on for petroleum refining' George V. Dyroff.
2. Diesel Fuels
2.1. Automotive Diesel Fuels
Types
No.1 Diesel Fuel (Super-diesel)
-
Used in high speed in automobiles (trucks, busses)
- Usually made from virgin (CDU) stocks
-
Have cetane number (45-50 min)
- BP range 360600 F
No.2 Diesel Fuel
- Lower cetane number (40 min)
- Has a wider BP range 360650 F
- Usually contains cracked stocks
Important Properties
1.
Ignition quality (cetane number or index)2. Volatility (Flash point)
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3.
Viscosity
4. Sulfur content
5. % Aromatics
6. Cloud point
Diesel Ignition Properties (Cetane number)- Very similar to the octane number.
- Compares the degree of combustion of diesel fuel to that of a mixture of
cetane (C16H34, high-ignition quality) and alpha-methyl-naphthalene (C11
H10, low ignition quality) expressed as V% cetane.
Cetane -methylnaphthalene
Lower S & aromatics content, lowers the particulate emissions from diesel engines.
2.2. Railroad Diesel Fuels
Used for railroads
Similar to the heavier automotive diesel fuels, except,
- Have higher BP ranges (up to 750 F end point)
- Lower cetane numbers (30 min.)
3. Heating oils
Its consumption ranks very high from Petroleum product, but has recently decreased
in favor of LPG.
Types:No.1 Fuel Oil: (V. similar to Kerosene, with higher pour and end points)
No.2 Fuel Oils: (Similar to No.2 diesel fuel).
Limiting Specs are: 1. Distillation2. Pour point
3. Flash point
4. Sulfur content
4. Residual Fuel Oils
Composed of the heaviest parts of the crude, generally, the vacuum unit fractionating
tower bottoms.
Types:
HSFO: Sells for very low price (70% of the crude oil).
LSFO: Heavy fuels oils with very low sulfur (price of crude).
Critical Specs are
1. Viscosity
2. Sulfur Content (Generally governed by the locality in which it is burned, i.e.
Africa, America).
No. 16 fuel oils
.
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The heaviest part of petroleum; Tar, pitch, asphalt and bitumenare often used
interchangeably although they are different
1. Tar
A viscous black liquid Derived from the destructive distillation of organic matter.
Tar is predominantly composed of bitumen (Contains less bitumen than asphalt
does).
Is considered toxic and carcinogenic because of its high benzene contents.
Coal and petroleum tar has pungent or repulsive odor
Tar is used in treatment of the
skin-disease psoriasis. It is also a
general disinfectant. Petroleum
tar was also used in ancient
Egyptian mummification. Tar wasa vital component of the first
sealed roads. It was also used as
seal for roofing shingles and to
seal the hulls of ships and boats.
Tar
2. Asphalt
Asphalt is composed almost entirely of bitumen (Contains more bitumen than Tar
does).
Asphalt is a sticky, black and highly viscous liquid or semi-solid that is present in
most crude petroleum.
Asphalt can be separated from the other components in crude oil by processing of theVacuum Residue in a deasphalting unit, which uses either propane or butane in a
supercritical extraction. Further processing is possible by "blowing" the product:
namely reacting it with oxygen. This makes the product harder and more viscous.
The structure is most commonly modeled as a colloid, with asphaltenes as thedispersed phase and maltenes as the continuous phase.
Uses; There are two forms commonly used in construction: rolled asphalt and mastic
asphalt.
In the ancient times used for mortar between bricks and stones, ship caulking,
waterproofing, and mummification.
Rolled asphalt concrete; The largest use of asphalt is for making asphalt concrete forroad surfaces and accounts for approximately 80% of the asphalt consumed in the
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United States. Roofing shingles account for most of the remaining 20% asphalt
consumption. Other uses include cattle sprays, fence post treatments, and
waterproofing for fabrics.
Mastic asphalt; Mastic asphalt is a type of asphalt which differs from dense graded
asphalt (asphalt concrete) in that it has a higher bitumen (binder) content, usually
around 7-10% of the whole aggregate mix, as opposed to roller asphalt, which hasonly around 5% added bitumen.
Base layer of asphalt concrete in a road under
construction.
3. Bitumen
Bitumen is sometimes referred to as Asphalt
A mixture of organic liquids that are highly viscous, black, sticky, and composedprimarily of highly condensed polycyclic aromatic hydrocarbons.
The residual (bottom) fraction obtained by fractional distillation of crude oil; It is the
heaviest fraction and the one with the highest boiling point.
Bitumen is primarily used for paving roads and waterproofing products, including theuse of bitumen in the production of roofing felt, sealing flat roofs, waterproof boats,
and even as a coating for buildings.
4. Pitch
Is a highly viscous liquid which appears solid
Can be shattered with a hard impact
Flows at room temperature but extremely slowly
Uses: Pitch was traditionally used to help caulk the seams of wooden sailing
vessels
5. Coke
The heaviest refinery product
Is a solid with little volatile HC amount
The volatile matter is removed by calcination