chapter05 - feeds & products

7/24/2019 Chapter05 - Feeds & Products

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Petroleum RefiningChapter 5: Refinery Feeds and Products

5-1

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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Copyrights 2001-2015, Dr. Tareq Albahri, Chem. Eng. Dept., Kuwait University

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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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5-4

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

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