composition of oil - cybernetics
TRANSCRIPT
Crude oil
- composition and processing
2.9.2013
Tiina Komulainen
Based on Morten Holmager (2010), Offshore book – an introduction to the offshore industry, Offshore center Danmark.
Contents
• What is crude oil?
• Parameters
– Crude oil API-density
– sulfur content
– GOR
– WOR
• Design of oil separation
(topsides) process
• HSE
What is oil?
• Reservoir: mixture of – Gas components
– Oil components (light, heavy)
– Water
– Sand
• Separation – from multi-phase mixture to
crude oil (mixture of mainly oil components)
• Refining – From crude oil to products
like gasoline
Source: www.oilgaspath.blogspot.com
What is crude oil?
• Multi-phase flow from
reservoir typically a
mixture of:
– gas (C1 – C4)
– light oil /naptha (C5 – C9)
– paraffin oil (C10 – C16)
– diesel oils (C14 – C20)
– heavier oils(C20 – C70)
– asphaltene, bitume (C70+)
– sulphur
– water
– sand
Some important properties of oil components
Density ρ [kg/m3]
Viscosity μ [kg/ms], [cP]
Molecular weight M [g/mol]
Critical temperature TC [K]
Critical pressure PC [Pa]
Interaction with other components
ai [-]
CR
UD
E O
IL
What is crude oil?
• Mixture of hundreds of oil compounds
• Reservoir multi-phase flow -> separation & stabilization -
> crude oil, produced water, gas (,sand)
• Crude oil -> refinery -> products
TRANSPORT TO REFINERY
What is oil – crude oil separation
• Separation of multi-phase fluid (emulsion) of oil, gas,
water and sand
• Three-phase separator with different internal
equipment
• Typically requires multi-stage separation for acceptable
crude oil quality
– Does not gasify under export conditions (T,P)
– Low water content
– No sand
Crude oil density: API gravity
• Density of separated oil,
«crude oil»
• American Petroleum
Institute (API)
• Density of crude oil
(@15.6 ºC) compared to
density of water
(~1000kg/m3)
– light crude: API >32
– medium crude 22<API<32
– heavy crude: API<22
Source: http://nesteoil.com/default.asp?path=1,41,538,2035,5196,5197,5199
5.131
60,60,
5.141
5.1315.141
API
2
FOHFcrude
spg
Crude oil sulfur content
• High temperature at refinery -> sulfur components form sulfur dioxide (SO2) -> exhaust gas -> acid rain (H2SO4)
• Sweet crude (Sulfur <0.5%)
• Sour crude (Sulfur> 0.5%)
• Examples – Brent Blend is a light, sweet North Sea
crude with a sulfur content of approximately 0.4%
– Russian Export Blend is a medium, sour crude oil with a sulfur content of approximately 1.2%
Source: http://nesteoil.com/default.asp?path=1,41,538,2035,5196,5197,5199
Exercise 1 – light/heavy, sweet/sour?
Crude source
Paraffins vol%
Aromatics vol%
Naphtenes wt%
Sulfur %
API Naphta yield
Nigerian-1
37 9 54 0,2 36 28
Saudi-1 63 19 18 2 34 22
Saudi-2 60 15 25 2,1 28 23
Venezuela-1
35 12 53 2,3 30 2
Venezuela – 2
52 14 34 1,5 24 18
USA-Mid.
- - - 0,4 40 -
USA, Texas
46 22 32 1,9 32 33
North Sea- Brent
50 16 34 0,4 37 31
Source: Offshore book, 2010, p.9
Crude oil quality: impact on refining
• The quality of crude oil => level of processing and conversion for optimal mix of products
• Light, sweet crude is more expensive than heavier, sourer crude
– requires less processing
– More value-added products, such as gasoline, diesel, and aviation fuel.
• Heavier, sourer crude
– Additional pumping & diluting costs
– Lower percentage value-added products with simple distillation
– Requires additional processing (=requires more energy) to produce lighter products.
Source: http://nesteoil.com/default.asp?path=1,41,538,2035,5196,5197,5199 Offshore book
Petroleum production - separation
• Gas/oil/condensate/water separation
• High to low pressure
• Many process units – oil separation (gravity
separator) and treatment
– water treatment
– gas compression
• Products – Stabilized crude oil (to
refinery)
– Gas
– Condensate
– (Prod. water, sand)
Sources: www.offshorecenter.dk www.iet-engineering.com
Separation train - design
• Oil composion – Heavy components hard to
separate
– Emulsion with water
– Gas entrainment
• Reservoir pressure & temperature
• GOR and WOR developement over the life time of the field – Gas to Oil Ratio increases
– Water to Oil ratio increases
Separation train - design
• Separation of
components between gas
and liquid: vapor – liquid
equilibrium (VLE)
– Component properties
– Surface between V-L
• Separation of liquid
components between oil
and water phase:
gravitation
– Settling time -> separator
length
Separation train - design
• Vapor-liquid equilibrium
– Temperature, pressure
– Properties of the components
– Simple calculation: Sandler’s
equation
Some important properties of oil components
Density ρ [kg/m3]
Viscosity μ [kg/ms], [cP]
Molecular weight M [g/mol]
Critical temperature TC [K]
Critical pressure PC [Pa]
Interaction with other components
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Separation train - design
• Settling time
– Geometry of the separator
– Density of the different
components -> gravity
– Breaking of the emulsion
(water-sand-oil)
Some important properties of oil components
Density ρ [kg/m3]
Viscosity μ [kg/ms], [cP]
Molecular weight M [g/mol]
Critical temperature TC [K]
Critical pressure PC [Pa]
Interaction with other components
ai [-]
Separation train - design
• Number of separation
stages
– Desired crude oil composition
– Inlet pressure, temperature
– Typically 3 stages
• High Pressure (50 - 125 atm)
• Medium/ Intermediate Pressure
• Low Pressure (1- 10 atm)
• (coalescer 1atm)
• Goal: Maximal amount of
stabilized crude oil
– Minimal amount of water and
gas
– Condensate from scrubbers
Petroleum production - refining
• Crude oil processing at
an oil refinery
– Distillation, cracking,
separation,…
– Energy consumption!
– Amount of products
– Depends on the crude
quality and processing
options available
Source: www.energyinst.org.uk
What is oil – gasoline?
— Crude oil processed at
a refinery => various
products
— Most valuable products:
— Gasoline, diesel,
kerosene
— Gasoline is a blend of
alkanes.
— Mainly C5-C10
— Single bindings between
C-atoms
— Formula CnH2n+2
18
Name (CnH2n+2)
Methane CH4
Ethane C2H6
Propane C3H8
Butane C4H10
Pentane C5H12
Heksane C6H14
Heptane C7H16
Octane C8H18
Nonane C9H20
Decane C10H22
Exercise 2 – separation of crude oil
Presentasjonens tittel 02.09.2013
• Why reservoir fluid needs
to be processed before
refining?
• Which factors determine
the sizing of the
separator?
• Which factors determine
price of the crude oil
(compared to Brent)
Petroleum production - HSE
• Sustainable development
– responsible energy
production
– environmental protection
• Health
• Safety
• Environment
• Regulations
– ISO
– API (USA)
– Norsok (Norway)
Source: blog.cifor.org/
Petroleum production - health
• Crude oil – Mixture of over 200 different
hydrocarbon compounds
– Extremely flammable
– Toxic, carsinogenic
– Major damage to health & environment
• Work environment – safety precautions
• gloves, safety glasses, jacket, laboratory fume hood, explosion proof equipment,…
– avoid heat, sparks, open flames
– tightly closed container, ventilated area
Source: www.sciencephoto.com
Petroleum production – safety
• Temperature, pressure at
different parts of the
production chain
– Quality of materials, safety
and automation system,
operators, all employees,
local communities
(pipelines, transport)
• Danger of explosion
– Material damages
• Case examples drilling
rigs, refineries, etc
Petroleum production - environment
• Preserving the environment
– improve air quality (flaring)
– preserve water resources (spills)
– protect biodiversity
• By
– responsible waste management
– prevention and manage of accidental
pollution
– Improving energy efficiency
– Development of renewable energy
sources
Source: www.greenpacks.org
Petroleum production HSE
• What kind of experiences on
HSE policies do you have?
• Why Health Safety and
Environmental requirements
are important in petroleum
production plants?
• How can HSE awareness be
improved by education /
internal courses?
Oil producers
Verdens største oljeprodusenter 2012 (kilde: Forbes):
1. Saudi Aramco - 12,5 Mbpd
2. Gazprom (Russia) 9,7- Mbpd
3. National Iranian Oil Co. - 6.4 Mbpd
4. ExxonMobil - 5.3 Mbpd
5. PetroChina - 4.4 Mbpd
6. British Petroleum - 4.1Mbpd
7. Royal Dutch Shell - 3.9Mbpd
8. Pemex (Mexico) - 3.6Mbpd
9. Chevron - 3.5Mbpd
10. Kuwait Petroleum Corp. - 3.2Mbpd
11. Abu Dhabi National Oil Co. - 2.9Mbpd
12. Sonatrach (Algeria) - 2.7Mbpd
13. Total (France) - 2.7Mbpd
14. Petrobras (Brazil) - 2.6Mbpd
15. Rosneft (Russia) - 2.6Mbpd
16. Iraqi Oil Ministry - 2.3Mbpd
17. Qatar Petroleum - 2.3Mbpd
18. Lukoil (Russia) - 2.2Mbpd
19. Eni (Italy) - 2.2Mbpd
20. Statoil - 2.1Mbpd
21. ConocoPhillips – 2.0Mbpd
22. Petroleos de Venezuela - 1.9Mbpd
23. Sinopec (China)- 1.6Mbpd
24. Nigerian National Petroleum - 1.4Mbpd
25. Petronas (Malaysia) - 1.4Mbpd
Petroleum production
• Landbased petroleum exploration and refining: http://www.youtube.com/watch?v=8W8SW98-sXQ
• Production in Texas http://www.youtube.com/watch?v=9Py8-Xy9MKo
• Subsea production: http://www.youtube.com/watch?v=apUgpNU-pC0
• Ormen Lange (gas production): http://www.youtube.com/watch?v=gz45mP7trmU&list=PL3D2FA93D808614CC&index=1
Source: www.oilgaspath.blogspot.com