Petroleum Refining 101

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Petroleum Refining 101

• RMAUPG
• Binder / Mixture Subcommittee Meeting
• Boise, ID
• October 4, 2005

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Definition . . . .

• Petroleum Refining -
• Process by which impurities are removed from
  crude oil to produce asphalt.
• (Warning The remainder of this presentation
  will primarily focus on the processing of crude
  oil impurities / contaminants)

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OVERVIEW

• History of Refining
• What Is Crude Oil?
• Characteristics of the money makers
• - Gasoline Diesel
• Chemical Processes
• - Catalysts
• Propane Deasphalting (PDA)

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• Modern History of Petroleum Refining

• 1859 Drakes Oil Well Discovery
• 1860 First Refinery (80 Barrels per Day)
• 1900 Electricity and the Auto
• 1920 Thermal Cracking Lubric
  ants First Continuous Distillation
  Process
• 1940 WWII Catalytic Cracking,
  Alkylation
• 1950 Reforming
• 1960 Hydrocracking
• 1970 Fluidized Cat Cracking
• 1980 Environmental Improvements
• Present Refinement Optimization of
  Process Energy Recovery

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• What is a barrel of Crude?

• One Barrel 42 Gallons
• Hydrocarbons found in crude can be broken down
  into three general categories
• Paraffins - saturated hydrocarbons
• Naphthenes - cycloparaffins
• Aromatics - containing one or more benzene rings
• Boiling Range
• 70 deg F to 1200 deg F
• Olefins - not naturally occurring in crude,
  formed during processing

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• What is a barrel of Crude?

• Primary atomic building blocks
• Carbon 84 to 87 wt
• Hydrogen 11 to 14 wt
• Sulfur 0 to 6 wt
• Nitrogen 0 to 0.5 wt
• Impurities
• Water
• Sediment
• Salts
• Metals
• Nitrogen
• General Characteristics
• Density (API Gravity)
• Light 38 to 45 Degrees API Gravity
• Medium 28 to 38 Degrees API
• Heavy 12 to 28 Degrees API
• Sulfur
• Sweet 0.1 to 0.5 wt
• Semi-Sweet 0.5 to 0.8wt

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Paraffins in Crude Oil
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Naphthenes in Crude Oil
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Aromatics in Crude Oil
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Product Specification - Gasoline

• Specification

Purpose
Octane Number (RON, MON,Road ON)
Road Performance/Knock Ping
Vapor Pressure (RVP)
Easy Starting, vapor lock, environmental
Distillation Curve
Road performance (mileage, warm-up, acceleration
etc.)
Sulfur
Environmental
Aromatics, oxygen
Environmental
Gum
Storage stability, engine performance
Increased Octane paraffins olefins
branched chains cyclics aromatics
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Octane Number

• The power obtained from a conventional
  reciprocating gasoline engine is limited by two
  distinct types of abnormal combustion known as
  knock and rumble. When the fuel-air mixture in
  the cylinder of a spark-ignition engine burns
  spontaneously in localized areas instead of
  progressing from the spark, this explosive
  decomposition pro-duces a characteristic noise or
  knock. Rumble, on the other hand, is caused by
  multiple pre-ignitions of the fuel-air mixture
  during the compression stroke and is also
  recognized by a characteristic noise sometimes
  referred to as wild ping. In both cases, the
  accompanying pressure surge cannot be converted
  into mechanical work by the piston, which must
  move in a fixed time / position relationship, and
  is lost as heat to the engine cooling system and
  exhaust gas. In addition to loss of power and
  fuel economy, knocking can result in engine
  damage and may burn a hole in the piston. For
  these reasons, the antiknock quality of gasoline
  is one of their most important properties.
• The antiknock quality of motor gasoline is
  normally expressed in terms of octane number.
  The test fuel is compared to blends of two pure
  hydrocarbons, n-heptane and isooctane. N-heptane
  is quite low in its resistance to knock and has
  been arbitrarily assigned an octane value of
  zero. Isooctane has good antiknock properties
  and has therefore been assigned a value of 100.
  The octane number of a fuel is defined as the
  volume percentage of n-heptane and isooctane
  which matches the test fuel in knock intensity
  under standard conditions.

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• Product Specifications-Diesel

Specification
Purpose
Flash Point
Safety
Cetane No. 90 point and RCR (Carbon residue)
Engine Performance
Viscosity Cloud and Pour Points
Fuel Handling
Sulfur Content
Environment
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Purpose of Refineries
65 Octane
90 Octane
Hi Sulfur
Hi Pour Point
Waxy
Very Low Sulfur
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Five Basic Refinery Processes

• Separation by Boiling Range
• Distillation
• Crude Tower and Vacuum Crude Distillation
• All Fractionation towers (in most units)
• Cracking (Breaking Molecular Structures)
• Fluid Cat Cracker (FCC)
• Thermal Cracking
• Coking
• Hydrocracking
• Modifying Molecular Structures
• Isomerization
• Catalytic Reformer
• Combining Molecular Structures
• Alkylation
• Catalytic Polymerization
• Treating (Removing poisons and impurities)
• Hydrodesulfurization

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(No Transcript)
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Crude Distillation Unit
90 - 200 F
Light Straight Run
90 - 220 F
Naphtha
Naphtha
180 - 400 F
Crude Oil
Kerosene
330 - 540 F
Kerosene
Diesel
420 - 640 F
Diesel
Atmos. Gas Oil
550 - 830 F
Vacuum Gas Oil
Atmos. Resid 800F
800 - 1150 F
800 F
Vacuum Resid (Asphalt)
1150 F
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The Challenge!
Text Book Reaction R1R2R3.
P1P2P3
Temp, Pressure
Catalyst
Real World Reaction R1R2R3.Poisons
P1P2P3Side ReactionsCarbon
Temp, Pressure, Time
Catalyst
Heat
Heat
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• Cracking
• Fluidized Catalytic Cracking

• Purpose
• To convert heavy oils into gasoline and lighter
  products
• Feed
• 650 deg to 1100 deg crude cut heavy oils from
  other processes
• Products
• 20 C3/C4, 60 gasoline, 20 diesel
• By products Methane/Ethane, Very heavy and
  aromatic fuel oil
• Variables
• Temperature 980 to 1000 deg F
• Reaction time 2 to 3 seconds
• Catalyst Weight Ratio 7 lbs cat/1 lb oil
• Catalyst activity
• Carbon on catalyst
• Catalyst poisons

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FCC Catalyst

• Early Catalysts
• Naturally occurring clays
• Todays Catalysts - High Tech!
• Average particle size - 75 micron
• Zeolites (crystalline silica aluminates)
• Cell Size - 25 angstroms
• Number of Ion sites (promotes cracking reactions)
• Pore diameter and volume 80 A dia, 0.3cc/gm
• Matrix (binder)
• Usually active alumina and clay
• Enhances overall surface area - 150meters/gram!
• Rare Earth Oxides
• Enhances zeolite stability - 3.8 wt

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• Modification
• Isomerization

• Purpose
• To produce a higher octane gasoline blending
  components
• Feed
• Primarisly LSR Gasoline (Butane, Pentane and
  Hexane)
• Hydrogen
• Products
• High percentage of isoheptane and isohexane
  gasoline blending stock or isobutane used for
  feedstock to alkylation unit
• Catalyst
• Platinum (0.4wt) and chloride (1 wt) on a
  silica or silica alumina base
• Typically 1/16 in dia by 1/4 in long
• Process variables
• Reactor temperature 250 to 400 deg F
• Pressure 400 psig

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Isomerization Reactions Examples
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• Modification
• Catalytic Reforming

• Purpose
• To produce a high octane gasoline blending stock
• Hydrogen is produced as an important by-product
• Feed
• Gasoline boiling range naphtha 200 deg F to 400
  deg F
• Products
• High octane gasoline blending stock 85 wt
• Hydrogen 9 wt
• Fuel Gas 1 wt
• Propane and Butane 5 wt
• Catalyst
• Platinum (0.6wt), Rhenium (0.3wt ) and
  chloride (1 wt) on an alumina base
• Typically1/16 in dia by 1/4 in long
• Variables
• Temperature 950 deg F
• Pressure 150 psig
• Hydrogen partial pressure, needed to reduce
  carbon deactivation
• Catalyst activity

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Reformer Reaction Examples
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Reformer Reaction Examples (contd)
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• Combination
• Alkylation

• Purpose
• Convert low molecular weight olefins and
  isoparaffins to higher molecular weight
  isoparaffins(Gasoline)
• Feed
• Isobutane and butylene or propylene
• Products
• 100 Octane Gasoline blending stock (alkylate)
• gases, (n-butane, propane)
• tar (from side reactions)
• Catalyst
• Strong Acid, either Hydrofluoric or Sulfuric
• Process variables
• Temperature 60 to 100 deg F
• Acid strength Over 90
• Isobutane/Olefin ratio Over 14 to 1

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Alkylation Reaction Example
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• Combination
• Catalytic Polymerization

• Purpose
• To convert propylene and butylene to a gasoline
  blending stock
• Feed
• Propylene and butylene
• Products
• 90 Octane Gasoline blending stock, propane,
  butane and fuel gas
• Catalyst
• HFD (Phosphoric acid on a clay base)
• Process variables
• Temperature 420 deg F
• Pressure 500 psig
• Catalyst activity

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Catalytic Polymerization Reaction Example
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• Treating
• Hydrodesulfurization/Hydrotreating

• Purpose
• To remove sulfur, nitrogen and metal compounds
  from various feedstocks
• Feed
• A wide range of feed stocks
• Reformer Feed requires less than 1ppm sulfur
• Diesel product must be less than 500 ppm(going
  to 50ppm in next 7 years)
• Treat FCC feed to reduce Sulfur emissions and
  remove metal catalyst poisons
• Hydrogen
• Products
• A stabilized poison-free feedstock
• H2S and NH3
• Catalysts
• Cobalt-Molybdenum on bauxite base (better Sulfur
  Removal)
• Nickel-Molybdenum on bauxite base (better
  Nitrogen removal)
• Variables
• Temperature 600 to 800 deg F.
• Pressure 400 to 4000 psig

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HydroDesulfurization
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TreatingSulfur Production

• Purpose
• Convert dangerous H2S to elemental Sulfur
• Feed
• H2S gas
• Product
• Elemental Sulfur, liquid or solid
• Catalyst
• Activated Alumina
• Variables
• Reaction Furnace 2200 deg F
• Converter Beds 500 deg F
• Pressure 10 psig

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TreatingSulfur Recovery Claus Process
Temp
H2S 1.5O2 SO2 H2O
3H2S
Catalyst
2H2S SO2 3/n Sn 2H2O
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Propane Deasphalting (PDA)

• Purpose
• to separate gas oils from residual materials.
• Feed
• reduced crude from atmos or vacuum tower.
• Product
• hard pen product used as road oil or bunker (6)
• Variables
• propane to charge stock ratio 71 to 81
• temperature distribution bottom tower 120F,
  top tower 155F

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• Simple Refinery Flow Diagram

Sulfur Recovery
Refinery Fuel Gas
Amine Unit
Gas Plant
Off Gas
Natural Gas Liquids
LSR Gasoline to Blending
Isom
Cat Reformer
Naphtha
Gasoline Blending
Crude Unit
Crude
Kerosene/Jet
Kerosene/Jet Blending
Hydrotreater
Distillate
Distillate Blending
Hydrotreater
Atmos. Gas Oil
Cat Cracker (FCC)
Gasoline Blending
Vacuum Unit
Alky
VGO
P-B's
VGO
Cat Poly
Atmos. Resid
Gasoline Blending
Gasoline
Coker
Jet/Kerosene
Vac. Resid
Distillate
Coke Sales