A CATALOGUE OF CRUDE
OIL AND OIL PRODUCT PROPERTIES
P. Jokuty 1, S. Whiticar
2, Z. Wang 1, M. Fingas 1,
P. Lambert 1, B. Fieldhouse 1, and J. Mullin 3
1 Emergencies Science
Division, Environment Canada, Ottawa, Ontario
2 Whiticar Scientific, Ottawa, Ontario
3 United States Minerals Management Service, Department of the
Interior, Herndon, Virginia
This report has not undergone
detailed technical review by the Environmental Protection Directorate and
the content does not necessarily reflect the views and policies of Environment
Canada. Mention of trade names or commercial products does not constitute
endorsement for use. This unedited version is undergoing a limited distribution
to transfer the information to people working in related areas. This distribution
is not intended to signify publication and, if the report is referenced,
it should be cited as a manuscript report of the Directorate indicated
below. Any comments concerning its content should be directed to:
Environmental Technology Advancement
Emergencies Science Division
Environmental Technology Centre
This catalogue provides data on
various physical-chemical properties of crude oils and petroleum products.
The properties that are reported are those which will likely determine
the environmental behaviour and effects of spilled oil. The oils are arranged
in alphabetical order.
This project was co-funded by
the United States Minerals Management Service and the Emergencies Science
Division of Environment Canada. The authors thank all those who supplied
samples and technical data.
TABLE OF CONTENTS
of Oils (Alphabetical by Oil Name)
of Tests and Methods
Limits of Vapour in Air
Viscosity/Emulsion Water Content
Tension and Interfacial Tension
Oxygen Demand (BOD)
During any oil spill incident,
the properties of the spilled oil must be known immediately. Unfortunately,
the properties routinely measured by oil producers and refiners are not
the ones that on-scene commanders need to know most urgently. Oil producers
and refiners typically do not know to what extent their oils will evaporate
and how quickly; to what extent dispersibility will occur naturally, or
be enhanced with dispersants; whether emulsions will form; if the oil is
likely to sink or submerge; the viscosity of the oil, at ambient temperatures,
as it evaporates; the health hazard to on-site personnel from volatile
organic compounds; and the toxicity to marine or aquatic organisms.
The Emergencies Science Division
(ESD), also known as the Environmental Emergencies Technology Division
(EETD) prior to 1990, of Environment Canada, (the Canadian counterpart
of the U.S. Environmental Protection Agency), is an organization that has
been dedicated to performing oil and chemical spill research since 1973.
Since 1984, Environment Canada has been analyzing crude oils and oil products
to determine not only basic physical properties, but also how oil behaves
when spilled in the environment. A catalogue of oil properties, containing
both data produced in-house and data from other sources, was first prepared
by Environment Canada in 1984. Subsequent updates were produced in 1986,
1988, 1989, 1990, and 1992. A Catalogue of Crude Oil and Oil Product Properties
has been so popular that interagency committees have requested that data
collection for, and updating of the catalogue, be an ongoing operation.
This work has been continuously co-funded by the U.S. Minerals Management
Service since 1989. The oil properties database presently contains information
on over 350 different oils.
For each oil in the catalogue,
the properties listed are those that indicate a spilled oil's environmental
behaviour and effects. Where available, data is included for both fresh
and evaporated oils. Environment Canada is the largest single source of
data for the oil catalogue. Whenever possible, Environment Canada has used
standard test methods, such as those of the American Society for Testing
and Materials (ASTM). In addition, many oil analytical methods have been
developed by ESD specifically for determining the environmentally significant
properties and behaviours that oil producers and refiners do not measure.
These include methods for emulsion formation and characterization, measuring
chemical dispersibility, determining specific and generalized evaporation
equations for oils, measuring volatile organic compounds, and determining
acute aquatic toxicity. Because evaporative loss results in significant
changes in the physical properties and chemical composition of spilled
oils, which in turn influence choices made relating to oil spill countermeasures,
ESD measures most properties not only for fresh oils, but also for evaporated
oils prepared in the laboratory to represent various degrees of evaporation
(see the Appendix of Methods, Bulk Evaporation of Oils). The information
collected is maintained in an electronic database and also used to produce,
at intervals, A Catalogue of Crude Oil and Oil Product Properties.
Most of the oil analytical
methods used by ESD are described in the Appendix of Methods. Some ESD
methods have been previously described in detail in the literature and
the reader is referred to these sources to avoid unnecessary repetition.
Since data from many other
sources are also included in the catalogue, differences in reported values
may be due to the variance of samples and inherent differences in measurement
techniques. The reader who wishes to make use of such data should refer
directly to the original source to obtain specific details on the techniques
and parameters used.
The crude oils and oil products
are arranged in alphabetical order. Oil products are listed according to
their most commonly used names. All synonyms are cross referenced in the
Table of Contents. In addition to a complete alphabetical listing, a listing
by geographic origin has also been included. The names used to identify
the oils in this catalogue are those used by the authors of the original
data or by the suppliers of the samples. Common synonyms are included where
The reader should be aware
of the following points when searching for information on a specific oil.
Crude oils from the same region are often given the same name even though
oils from different wells can have markedly different properties. Oils
that are transported are often blends of different crude oils, and the
relative proportions of component oils frequently change. Therefore, the
physical and chemical properties will vary. Similarly, the properties of
oil taken from an individual well can vary with the depth of the well and
the year of production. Also, different authors may refer to the same crude
oil by different names, or to different crude oils by the same name.
DESCRIPTION OF TESTS AND METHODS
Some of the oils analyzed by ESD
contain substantial amounts of water. Because any process that would separate
the oil and water would also change the composition of the oil, most properties
were determined on the oils as received. Exceptions are noted in the individual
data tables. Therefore, for those oils with significant water contents,
(>5%), many of the properties measured do not represent the properties
of the "dry" oil.
At ESD, water contents were
determined by Karl Fischer titration using a Metrohm 701 KF Automatic Titrator.
A slightly modified version of ASTM method D 4377 was used (ASTM, 1996a).
For more details, see the Appendix of Methods.
Evaporation is a major process
which contributes to the weathering of spilled oil. While pure compounds
evaporate at constant rates, oils, which are composed of thousands of compounds,
do not. Rapid initial loss of the more volatile fractions is followed by
progressively slower loss of less volatile components. It is not uncommon
for 25% of the total volume of an oil spill to evaporate within one day
of the spill (Fingas et al., 1979).
Using a simple pan evaporation
technique, evaporation rate equations have been developed for approximately
60 oils. For more details, see the Appendix of Methods, Pan Evaporation
The flash point of a fuel is the
temperature to which the fuel must be heated to produce a vapour/air mixture
above the liquid fuel that is ignitable when exposed to an open flame under
specified test conditions. In North America, flash point is used as an
index of fire hazard. As such, shipping regulations use flash point as
a criterion to establish labelling requirements.
Flash point is an extremely
important factor in relation to the safety of spill cleanup operations.
Gasolines and other light fuels can be ignited under most ambient conditions
and therefore pose a serious hazard when spilled. Many freshly spilled
crude oils also have low flash points until the lighter components have
evaporated or dispersed.
There are several ASTM methods
for measuring flash points. Methods D 93/IP 34 - Standard Test Methods
for Flash Point by Pensky-Martens Closed Tester and D 56 - Standard Test
Method for Flash Point by Tag Closed Tester are among the most commonly
used (ASTM, 1996a). The Pensky-Martens tester has an integral stirrer,
but no cooling bath. The minimum flash point that can be determined by
method D93/IP34 is 10 'C. The Tag closed tester has an integral cooling
bath, but no stirring mechanism. Method D 56 is intended for liquids with
a viscosity less than 9.5 cSt at 25 'C. The flash points and fire points
(see below) of lubricating oils can be determined by ASTM method D 92/IP
36 - Standard Test Method for Flash and Fire Points by Cleveland Open Cup
Many fresh crude oils have
flash points below 10 /C and/or viscosities above 9.5 cSt at 25 'C. For
this reason, at ESD a SUR BERLIN TAG 2 automatic flash point tester, which
has been modified by adding a stirring mechanism, is used to determine
flash points. The mechanism operates in a similar fashion to a Pensky-Martens
tester, but is of a more efficient design. The stirrer aids in producing
more uniform heat transfer to oils that exceed the design viscosity, and
in no way interferes with the test mechanism. Flash points measured by
this instrument are generally repeatable to +/- 4 'C. For more details,
see the Appendix of Methods.
In the data section, flash
points taken from the literature, and determined by open-cup or closed-cup
testers are designated by '(O.C.)' and '(C.C.)', respectively. No designation
is provided if the testing method is not known.
Fire point is the lowest temperature,
corrected to one atmosphere pressure (101.3 kPa), at which the application
of a test flame to the oil sample surface causes the vapour of the oil
to ignite and burn for at least five seconds. For ordinary commercial lubricating
oils, the fire point usually runs about 30 /C above the flash point (Esso
Petroleum Canada, 1990). The flash points (see above) and fire points of
lubricating oils can be determined by ASTM method D 92/IP 36 - Standard
Test Method for Flash and Fire Points by Cleveland Open Cup (ASTM, 1996a).
Flammability Limits of Vapour
The percent concentration in air
(by volume) is given for the lower and upper limit. These values give an
indication of relative flammability. The limits are sometimes referred
to as "lower explosive limit" (LEL) and "upper explosive limit" (UEL).
Sometimes called "autoignition
temperature", this is the minimum temperature at which the material will
ignite without a spark or flame being present. The method of measurement
is given in ASTM method E 659 - Standard Test Method for Autoignition Temperature
of Liquid Chemicals (ASTM, 1996b).
Reid Vapour Pressure
Vapour pressure is an important
physical property of volatile liquids. It is the pressure that a vapour
exerts on its surroundings. Its units are kilopascals, corrected to one
atmosphere (101.3 kPa). For volatile petroleum products, vapour pressure
is used as an indirect measure of evaporation rate. Vapour pressure can
be measured by a variety of methods including Reid, dynamic, static, isoteniscopic,
vapour pressure balance, and gas saturation. The most commonly used method
for crude oils has been the Reid vapour pressure, as determined by ASTM
method D 323 - Standard Test Method for Vapor Pressure of Petroleum Products
(Reid Method), (ASTM, 1996a). This test method determines vapour pressure
at 37.8 'C (100 'F) of petroleum products and crude oils with initial boiling
point above 0 'C (32 'F). It is measured by saturating a known volume of
oil in an air chamber of known volume and measuring the equilibrium pressure
which is then corrected to one atmosphere (101.3 kPa).
Unlike other sulphur compounds
in crude oils, which tend to accumulate in the distillation residue, hydrogen
sulphide is evolved during distillation or other heating processes. During
an oil spill, this makes it a safety concern, as hydrogen sulphide is a
toxic gas with a time-weighted average (TWA) exposure limit of 10 ppm and
a short-term exposure limit (STEL) of 15 ppm (ACGIH, 1996).
This is the lowest concentration
in air that most humans can detect by smell. The value cannot be relied
on to prevent overexposure because human sensitivity to odours varies over
wide limits, some chemicals cannot be smelled at toxic concentrations,
odours can be masked by other odours, and some compounds rapidly deaden
the sense of smell (CHRIS, 1991).
Density is defined as the mass
per unit volume of a substance. It is most often reported for oils in units
of g/mL or g/cm3, and less often in units of kg/m3.
Density is temperature-dependent. The figure below shows how the density
of water changes with both salinity and temperature. Oil will float on
water if the density of the oil is less than that of the water.
This will be true of all fresh
crude oils, and most fuel oils, for both salt and fresh water. Bitumens
and certain residual fuel oils may have densities greater than 1.0 g/mL
and their buoyancy behaviour will vary depending on the salinity and temperature
of the water. The density of spilled oil will also increase with time,
as the more volatile (and less dense) components are lost. After considerable
evaporation, the density of some crude oils may increase enough for the
oils to sink below the water surface.
Two density-related properties
of oils are often used: specific gravity and American Petroleum Institute
(API) gravity. Specific gravity (or relative density) is the ratio, at
a specified temperature, of the oil density to the density of pure water.
The API gravity scale arbitrarily
assigns an API gravity of 10/ to pure water. API gravity is calculated
Oils with low densities, and
hence low specific gravities, have high API gravities. The price of a crude
oil is usually based on its API gravity, with high gravity oils commanding
higher prices. API gravity, and density or specific gravity at 15 /C, can
be interconverted using Petroleum Measurement Table 3 (American Petroleum
At ESD, density is measured
using an Anton Parr DMA 48 digital density meter, and following ASTM method
D 5002 - Density and Relative Density of Crude Oils by Digital Density
Analyzer (ASTM, 1996a). In this way, densities can be measured to 0.0001
g/mL with a repeatability of "0.0005 g/mL. For more details, see the Appendix
The pour point of an oil is the
lowest temperature at which the oil will just flow, under standard test
conditions. The failure to flow at the pour point is usually attributed
to the separation of waxes from the oil, but can also be due to the effect
of viscosity in the case of very viscous oils. Also, particularly in the
case of residual fuel oils, pour points may be influenced by the thermal
history of the sample, that is, the degree and duration of heating and
cooling to which the sample has been exposed.
From a spill response point
of view, it must be emphasized that the tendency of the oil to flow will
be influenced by the size and shape of the container, the head of the oil,
and the physical structure of the solidified oil. The pour point of the
oils is therefore an indication, and not an exact measure, of the temperature
at which flow ceases (Dyroff, 1993).
ESD uses a modified version
of ASTM method D 97 - Standard Test Method for Pour Point of Petroleum
Oils (ASTM, 1996a) for pour point determinations. For more details, see
the Appendix of Methods.
Viscosity is a measure
of a fluid's resistance to flow; the lower the viscosity of a fluid, the
more easily it flows. Like density, viscosity is affected by temperature.
As temperature decreases, viscosity increases. The SI unit of dynamic viscosity
is the millipascal-second (mPa.s). This is equivalent to the
former unit of centipoise (cP).
Viscosity is a very
important property of oils because it affects the rate at which spilled
oil will spread, the degree to which it will penetrate shoreline substrates,
and the selection of mechanical spill countermeasures equipment.
Viscosity measurements may
be absolute or relative (sometimes called 'apparent'). Absolute viscosities
are those measured by a standard method, with the results traceable to
fundamental units. "Absolute viscosities are distinguished from relative
measurements made with instruments that measure viscous drag in a fluid,
without known and/or uniform applied shear rates." (Schramm, 1992). An
important benefit of absolute viscometry is that the test results are independent
of the particular type or make of viscometer used. Absolute viscosity data
can be compared easily between laboratories worldwide.
Modern rotational viscometers
are capable of making absolute viscosity measurements for both Newtonian
and non-Newtonian fluids at a variety of well controlled, known, and/or
uniform shear rates. Unfortunately, no ASTM standard method exists that
makes use of these viscometers. Nonetheless, these instruments are in widespread
use in many industries.
Prior to 1989, the dynamic
viscosity results reported by EETD were measured using a Brookfield LVT
viscometer. For non-Newtonian oils, the viscosity measurements were usually
performed at shear rates of 1/s and 10/s. Dynamic viscosity data referenced
as 'EETD 89' or 'ESD xx' were determined using a HAAKE RV20 Rotovisco with
the M5 measuring system, SV1 and NV sensors, and HAAKE RC20 Rheocontroller.
The Rheocontroller, which is connected to a personal computer, allows the
shear rates to be controlled with great accuracy and precision. A dedicated
software package performs automatic dynamic viscosity measurements and
outputs the stored data in table and graphical formats. In general, the
viscosity values obtained using this system will be repeatable to +/-5%
of the mean. For more details, see the Appendix of Methods.
There are several
ASTM Standard Methods for measuring the viscosity of oils. Of these, only
methods D 445 - Standard Test Method for Kinematic Viscosity of Transparent
and Opaque Liquids (the Calculation of Dynamic Viscosity) and D 4486 -
Standard Test Method for Kinematic Viscosity of Volatile and Reactive Liquids,
will yield absolute viscosity measurements (ASTM, 1996a). Both of these
methods make use of glass capillary kinematic viscometers and will produce
absolute measurements in units of centistokes (cSt) only for oils that
exhibit Newtonian flow behaviour (viscosity independent of the rate of
The kinematic viscosity
results reported by EETD were measured using Zeitfuchs cross-arm capillary
viscometers and following ASTM method D 445.
Although now obsolete,
at one time the petroleum industry relied on measuring kinematic viscosity
with the Saybolt viscometer and expressing kinematic viscosity in Saybolt
Universal Seconds (SUS) or Saybolt Furol Seconds (SFS). Occasionally, Saybolt
viscosities are still reported in the literature. ASTM practice D 2161
- Standard Practice for Conversion of Kinematic Viscosity to Saybolt Universal
Viscosity or to Saybolt Furol Viscosity (ASTM, 1996a) establishes the official
equations relating SUS and SFS to the SI kinematic viscosity units, mm2/s.
A water-in-oil emulsion is a stable
dispersion of small droplets of water in oil. When formed from crude oils
spilled at sea, these emulsions can have very different characteristics
from their parent crude oils. This has important implications for the fate
and behaviour of the oil and its subsequent cleanup. It is desirable, therefore,
to determine if an oil is likely to form an emulsion, and if so, whether
that emulsion is stable, and what its physical characteristics are.
At ESD, prior to 1994,
the tendency for a crude oil to form a water-in-oil emulsion was measured
using a method based on the rotating flask apparatus of Mackay and Zagorski
(1982). All numerical values (mostly ones or zeroes) based on this method
have subsequently been reduced to 'yes' or 'no', respectively, and indicate
the formation (or not) of an emulsion that remained stable 24 hours after
In 1994, a new method was developed
for the formation of water-in-oil emulsions. This method uses commercially
available equipment. The apparatus uses the same end-over-end type of rotation
as used by Mackay and Zagorski (1982), but the reproducibility is considerably
improved. The water-to-oil ratio, the fill volume, and the orientation
of the vessels were found to be important parameters affecting emulsion
formation. For more details, see the Appendix of Methods. Again, emulsion
formation tendency is reported as 'yes' or 'no'. Again, 'yes' indicates
that the emulsion remains stable after a period of at least 24 hours. The
term 'stability' implies a significant persistence of structure over time.
After examining the influence of many factors, it was found that water
content and emulsion viscosity are the two properties that can best be
used to define emulsion stability. Emulsions that had decreases of less
than 5% in water content, concurrent with viscosity increases to values
greater than 100,000 cP, were stable.
Emulsion Viscosity/Emulsion Water
These properties are
measured in substantially the same way as for oils. For more details, see
the Appendix of Methods.
In some oil spill situations and
under appropriate conditions, dispersants may be an effective countermeasure
for minimizing contamination of shorelines, or birds and mammals.
The Swirling Flask Test (SFT)
was developed for determining the effectiveness of various dispersants
with different oils. Oil and dispersant are pre-mixed in a ratio of 25:1
and applied to salt water (3.3%) in a ratio of 1:1200. Prior to 1994 quantitation
was done by ultraviolet/visible spectrometry of solvent extracts of the
dispersed oil. Details of the apparatus and procedures used are given in
the literature (Fingas et al., 1989a). Studies have also been done to determine
the effects of oil-to-water ratios and settling times (Fingas et al., 1989b)
and energy (Fingas et al., 1991; Fingas et al.,1992; Fingas et al., 1993).
In 1994 the SFT was modified to use quantitation by gas chromatograph with
flame ionization detection (GC/FID) (Fingas et al., 1995b).
The behaviour of crude oils at
sea is dominated by their chemistry. The main constituents of crude oils
can be grouped into several broad classes of compounds: saturates (including
waxes), aromatics, resins, and asphaltenes.
Saturates are alkanes with
structures of CnH2n+2 (aliphatics) or CnH2n
in the case of cyclic saturates (alicyclics). Small saturates (<C18)
are the most dispersible components of oils. Large saturates (waxes) can
produce anomalous evaporation, dispersion, emulsification, and flow behaviours.
Aromatics are compounds that
have at least one benzene ring as part of their chemical structure. The
small aromatics (one and two rings) are fairly soluble in water, but also
evaporate rapidly from spilled crude oil. Larger aromatics show neither
of these behaviours to any extent.
Resins and asphaltenes are
similar in many ways. Asphaltenes can be thought of as large resins. Both
groups are thought to be composed of condensed aromatic nuclei which may
carry alkyl and alicyclic systems containing heteroatoms such as nitrogen,
sulphur, and oxygen. Metals such as nickel, vanadium, and iron are also
associated with asphaltenes. Both groups do not appreciably evaporate,
disperse or degrade, and both groups stabilize water-in-oil emulsions when
they are present in quantities greater than 3% (Fingas, 1994).
Waxes are predominantly straight-chain
saturates with melting points above 20 oC.
The preceding definitions may
be overly simplistic given the complex chemical composition of petroleum.
A greater appreciation of oil chemistry and of how petroleum can be chemically
fractionated can be obtained from more detailed texts such as the one by
Speight (Speight, 1991).
Saturate, aromatic, and polar
contents can be determined using various techniques such as open column
chromatography, high pressure liquid chromatography (HPLC), or thin layer
chromatography with flame ionization detection (TLC/FID; also known by
the trade name Iatroscan). TLC/FID is usually restricted to determinations
on weathered oils, as significant losses of low boiling component are likely
with fresh oils. It should be noted that each technique will likely yield
Prior to 1989, EETD used hexane
for the precipitation of asphaltenes. Since then, ESD has used n-pentane
as the precipitation medium. Since 1994, at ESD hydrocarbon groups in fresh
and evaporated crude oils have been determined by using a combination of
old and new methods. Asphaltenes are precipitated from n-pentane. Waxes
can then be precipitated from a mixture of methyl ethyl ketone and dichloromethane
at -32oC. To separate saturates, aromatics, and resins, deasphaltened
oil (maltenes) is placed on an open silica column, and eluted sequentially
with solvents of increasing polarity. For more details, see the Appendix
of Methods. If the oil used has an initial boiling point (IBP) above 250
oC (determined by simulated distillation), a good mass balance
can be obtained (>95%). However, most fresh crude oils will have an IBP
well below 250 oC, and the loss of light ends during solvent
recovery results in a poor mass balance. Fortunately, by making the reasonable
assumptions that a) resin and asphaltene contents are not affected by evaporative
losses, and b) the aromatic portion of the lost light ends can be equated
to the BTEX plus C3-benzenes content (see Volatile Organic Compounds),
it is possible to calculate the distribution of hydrocarbon groups.
It has long been recognized that
different oils tend to adhere to surfaces to a greater or lesser degree.
A test was developed, using a standard surface, that gives a semi-quantitative
measure of this adhesive property.
For the purposes of this test,
oil adhesion is defined as the mass of oil per unit area that will remain
on a standard test surface, after 'dunking and draining' for 30 minutes,
under prescribed conditions. For more details, see the Appendix of Methods.
The standard procedure was developed using both fresh and evaporated oils
with a wide range of viscosities. Test parameters that were evaluated included
temperature, oil viscosity, time, and test-surface area. A recent study
has also determined that the relative adhesiveness of different oils is
independent of the type of surface material used (Jokuty et al., 1996).
Volatile Organic Compounds
Benzene, toluene, ethylbenzene,
and xylenes (BTEX), and substituted benzenes are the most common aromatic
compounds in petroleum, making up to a few percent of the total mass of
some crude oils. They are the most soluble and mobile fraction of crude
oil and many petroleum products, and as such, frequently enter soil, sediments,
and ground water because of accidental spills, leakage of petroleum fuels
from storage tanks and pipelines, and improper oil waste disposal practices.
BTEX are hazardous carcinogenic and neurotoxic compounds and are classified
as priority pollutants regulated by Environment Canada and the US Environmental
A rapid, reliable, and effective
method for direct determination of BTEX plus C3-substituted
benzenes has been developed using gas chromatography with mass spectrometric
detection (GC/MS). Details of the method are given in a paper by Wang et
Detailed compositional analysis
of petroleum can be obtained using gas chromatography with flame ionization
detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). A
method developed at ESD can provide distributions of n-alkanes, polyaromatic
hydrocarbons, and important biomarker compounds such as hopanes (Wang et
Surface Tension and Interfacial
Interfacial tension is the force
of attraction between the molecules at the interface of two fluids. At
the air/liquid interface, this force is often referred to as surface tension.
The SI units for interfacial tension are millinewtons per metre (mN/m).
These are equivalent to the former units of dynes per centimetre (dyne/cm).
The surface tension of an oil,
together with its viscosity, affects the rate at which an oil spill spreads.
Air/oil and oil/water interfacial tensions can be used to calculate a spreading
coefficient which gives an indication of the tendency for the oil to spread.
It is defined as:
Spreading Coefficient =
SWA - SOA - SWO
where SWA is water/air
interfacial tension, SOA is oil/air interfacial tension, and
SWO is water/oil interfacial tension.
Spreading to a thin slick is
likely if the spreading coefficient of an oil is greater than zero, and
the higher the spreading coefficient, the faster the spreading will occur
Unlike density and viscosity,
which show systematic variations with temperature and degree of evaporation,
interfacial tensions of crude oils and oil products show no such correlations.
Nor is there any correlation to viscosity (Jokuty et al., 1995).
A single ASTM method, D 971
- Standard Test Method for Interfacial Tension of Oil Against Water by
the Ring Method (ASTM, 1996a), is applicable to the measurement of oil/water
interfacial tensions. At EETD, measurements were taken using a Fisher Surface
Tensiometer Model 21. ESD measurements made prior to 1993 used a CSC Du
Nouy Tensiometer #70545. Since 1993, ESD has made interfacial and surface
tension measurements using a Kruss Digital Tensiometer K10ST. This instrument
uses the Du Nouy principle for measuring interfacial tension, as recommended
in the ASTM method. Unlike manually operated ring tensiometers, the maximum
deformation of the lamella is detected electronically, and occurs before
the ring pulls completely through the interface. This results in interfacial
tensions that are slightly lower than those measured manually. Repeatability
is +/-2% of the mean. For more details, see the Appendix of Methods.
Boiling Point Distributions
In the oil refining industry,
boiling range distribution data are used to evaluate new crudes, to confirm
crude quality before purchase, to monitor crude quality during transportation,
and to provide information for the optimization of refinery processes.
From the point of view of oil analysis for environmental purposes, boiling
range distributions provide an indication of volatility and component distribution.
In addition, this data can be used as input to some oil spill modelling
programs. Boiling range distribution data may also prove to be useful in
the development of equations for predicting evaporative loss.
Traditionally, boiling range
distributions have been determined by distillation. 'Yield on crude' data
are still widely reported in the oil assay literature, providing information
on the yield of specific fractions obtained from a crude oil. Although
by no means universal, the following is a commonly used set of petroleum
fractions and their corresponding true boiling point (TBP) cut points:
||TBP Cut Points, C
||TBP Cut Points, F
|Light straight-run gasoline
|Atmospheric gas oil
|Vacuum gas oil
Atmospheric and vacuum distillation
techniques have largely been replaced by 'simulated' distillation methods.
These methods use low resolution gas chromatography and correlate retention
times to hydrocarbon boiling points. ASTM methods D 2887 - Standard Test
Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
and D 3710 - Standard Test Method for Boiling Range Distribution of Gasoline
and Gasoline Fractions by Gas Chromatography use external standards composed
of n-alkanes (ASTM, 1996a). ASTM method D 5307 - Standard Test Method for
Determination of Boiling Range Distribution of Crude Petroleum by Gas Chromatography
is very similar to D 2887, but requires two runs to be made with each sample,
one of which uses an internal standard (ASTM, 1996a). The amount of material
boiling above 538 oC (reported as residue) is calculated from
the differences between the two runs.
At ESD, boiling point distributions
are determined by simulated distillation with an AC Analytical Controls
SIMDIS analyzer, comprised of a Hewlett Packard 5290 Series II gas chromatograph
with an Analytical Controls Programmable Temperature Vaporizer (PTV) injector.
The system uses a special high-temperature column and is capable of determining
boiling point distributions between 35 oC and 750 oC.
For more details, see the Appendix of Methods.
Metal content in crude oils can
provide valuable information about the origin of those oils, potentially
aiding in identifying the source of oil spills. Crude oil assays often
include nickel and vanadium contents due to the detrimental effects of
these metals on catalysts used in cracking and desulphurization processes.
In lubricating oils, metal contents can provide information on both the
types of additives used in the oil and on the wear history of the equipment
being lubricated. ASTM method D 5185 - Standard Test Method for Determination
of Additive Elements, Wear Metals, and Contaminants in Used Lubricating
Oils and Determination of Selected Elements in Base Oils by Inductively
Coupled Plasma Atomic Emission Spectrometry (ICP-AES), (ASTM, 1996a) can
be used to determine over 20 different metals in a variety of petroleum
To overcome problems inherent
in the direct analysis of xylene solutions by ICP/AES, a method was developed
at ESD using microwave digestion of oils with nitric acid (Cao, 1992; Fingas
et al., 1995).
The sulphur content of a crude
oil is important for a number of reasons. Downstream processes such as
catalytic cracking and refining will be adversely affected by high sulphur
contents. During an oil spill, the sulphur content becomes a health and
safety concern for cleanup personnel. In addition, if high sulphur oils
are burning, they can produce dangerous levels of sulphur dioxide.
The total sulphur content of
oil can be determined by numerous standard techniques. ASTM method D 129
- Standard Test Method for Sulfur in Petroleum Products (General Bomb Method)
(ASTM, 1996a) is applicable to petroleum products of low volatility and
containing at least 0.1 mass percent sulphur (ASTM, 1996a). Sulphur contents
from EETD and ESD were determined using a Horiba MESA 200 sulphur and chlorine
analyzer, in accordance with ASTM method D 4294 - Standard Test Method
for Sulfur in Petroleum Products by Energy-Dispersive X-Ray Fluorescence
Spectroscopy (ASTM, 1996a). This method is applicable to both volatile
and non-volatile petroleum products with sulphur concentrations ranging
from 0.05 to 5 mass percent.
The solubility of oil in water
can be determined by bringing to equilibrium a volume of oil and water,
and then analyzing the water phase. This analysis can be done by purging
and trapping the dissolved hydrocarbons or, alternatively, directly analyzing
the headspace above the water.
Since oil is a complex mixture
of components and each component has a different solubility in water, an
oil's aqueous solubility is expressed as the cumulative concentration of
the individually dissolved components. The composition and concentration
of the solubilized mixture will depend upon conditions used during equilibration.
The term 'solubility' as applied to oils is being replaced by the technically
more precise term 'water-soluble fraction'. The values reported in this
catalogue were taken from those studies where an excess of oil was used
(oil-to-water volume ratios of at least 1:20) and where the processes of
evaporation and oil-in-water emulsification were prevented. Results reported
by ESD were obtained as described in the Appendix of Methods.
Toxicity values in this catalogue
may be reported as:
Median lethal concentration is
the estimated concentration of a compound that will cause death to 50 percent
of the test population in a specified time after exposure. In most instances,
LC50 is statistically derived by analysis of mortalities in
various test concentrations after a fixed period of exposure.
Median effective concentration
is used when an effect other than death is the observed endpoint. EC50
is the estimated concentration of the compound in water that will have
a specific effect on 50 percent of the test population in a specified time
after exposure. As with LC50, the EC50 is generally
Median tolerance limit; a term
sometimes used instead of EC50.
Biological Oxygen Demand (BOD)
Also called 'biochemical oxygen
demand', this is the standard way of describing how much oxygen, dissolved
in water, is consumed by biological oxidation of the chemical during the
stated period of time. The unit lb/lb indicates the pounds of oxygen consumed
by each pound of chemical during the time stated. When given in percent,
the values indicate the pounds of oxygen consumed by each 100 pounds of
chemical during the time stated (CHRIS, 1991).
ACGIH, 1996 Threshold Limit Values
for Chemical Substances and Physical Agents; Biological Exposure Indices,
American Conference of Governmental Industrial Hygienists ACGIH, Cincinnati,
American Petroleum Institute,
Petroleum Measurement Tables - Volume XI/XII, American Society for Testing
and Materials, Philadelphia, Pennsylvania, 1982.
ASTM, 1996 Annual Book of ASTM
Standards - Section 5 Petroleum Products, Lubricants, and Fossil Fuels,,
American Society for Testing and Materials, West Conshohocken, Pennsylvania,
ASTM, 1996 Annual Book of ASTM
Standards - Section 14, American Society for Testing and Materials, West
Conshohocken, Pennsylvania, 1996b.
Cao, J.R., Microwave Digestion
of Crude Oils and Oil Products for the Determination of Trace Metals and
Sulphur by Inductively-Coupled Plasma Atomic Emission Spectroscopy, Environment
Canada Manuscript Report Number EE-140, Ottawa, Ontario, 82 pp., 1992.
CHRIS, Chemical Hazards Response
Information System (CHRIS), United States Coast Guard, Department of Transportation,
Washington, D.C., 1991.
Dyroff, George V. (ed.), Manual
on Significance of Tests for Petroleum Products: 6th Edition, American
Society for Testing and Materials, Philadelphia, Pennsylvania, 1993.
Esso Petroleum Canada, Product
Information - Lubricants and Specialties (7th edition), 1990.
Fingas, M.F., "Chemistry of
Oil and Modelling of Spills", Journal of Advances in Marine Technology
Conference, vol. 11, pp. 41-63, 1994.
Fingas, M.F., AThe Evaporation
of Oil Spills@, Proceedings of the 18th Arctic and Marine Oil Spill Program
Technical Seminar, Environment Canada, Ottawa, Ontario, pp. 43-60, 1995.
Fingas, M.F., W.S. Duval, and
G B. Stevenson, The Basics of Oil Spill Cleanup, Environment Canada, Ottawa,
Fingas, M.F., V.M. Dufort,
K.A. Hughes, M.A. Bobra, and L.V. Duggan, "Laboratory Studies on Oil Spill
Dispersants", Chemical Dispersants - New Ecological Approaches, M. Flaherty,
(ed.), ASTM STP 1084, American Society for Testing and Materials, Philadelphia,
Pennsylvania, pp. 207-219, 1989.
Fingas, M.F., D.L. Munn, B.
White, R.G. Stoodley, and I.D. Crerar, "Laboratory Testing of Dispersant
Effectiveness", Proceedings of the 1989 Oil Spill Conference, American
Petroleum Institute, Washington, D.C., pp. 365-373, 1989.
Fingas, M.F., D.A. Kyle, I.E.
Bier, A. Lukose, and E.J. Tennyson, "Physical and Chemical Studies on Oil
Spill Dispersants: The Effect of Energy", Proceedings of the 14th Arctic
and Marine Oil Spill Program Technical Seminar, Environment Canada, Ottawa,
Ontario, pp. 87-106. 1991.
Fingas, M.F., D.A. Kyle, and
E.J. Tennyson, "Physical and Chemical Studies on Oil Spill Dispersants:
Effectiveness Variation with Energy", Proceedings of the 15th Arctic and
Marine Oil Spill Program Technical Seminar, Environment Canada, Ottawa,
Ontario, pp. 135-142, 1992.
Fingas, M.F., D.A. Kyle, and
E.J. Tennyson, "Physical and Chemical Studies on Dispersants: The Effect
of Dispersant Amount on Energy", Proceedings of the 16th Arctic and Marine
Oil Spill Program Technical Seminar, Environment Canada, Ottawa, Ontario,
pp. 861-876, 1993.
Fingas, M.F., B. Fieldhouse,
L. Gamble, and J. Mullin, AStudies of Water-in-Oil Emulsions: Stability
Classes and Measurement@, Proceedings of the 18th Arctic and Marine Oil
Spill Program Technical Seminar, Environment Canada, Ottawa, Ontario, pp.
Fingas, M.F., D.A. Kyle, P.
Lambert, Z. Wang, and J. Mulling, AAnalytical Procedures for Measureing
Oil Spill Dispersant Effectiveness in the Laboratory@, Proceedings of the
18th Arctic and Marine Oil Spill Program Technical Seminar, Environment
Canada, Ottawa, Ontario, pp. 339-354, 1995b.
Fingas, M.F., F. Ackerman,
P. Lambert, K. Li, Z. Wang, J. Mullin, L. Hannon, D. Wang, A. Steenkammer,
R. Hiltabrand, R. Turpin, and P. Campagna, AThe Newfoundland Offshore Burn
Experiment: Further Results of Emissions Measurement@, Proceedings of the
18th Arctic and Marine Oil Spill Program Technical Seminar, Environment
Canada, Ottawa, Ontario, pp. 915-995, 1995c.
Jokuty, P., M.F. Fingas, S.
Whiticar, and B. Fieldhouse, A Study of Viscosity and Interfacial Tension
of Oils and Emulsions, Environment Canada Manuscript Report Number EE-153,
50 pp., Ottawa, Ontario, 1995.
Jokuty, P., S. Whiticar, K.
McRoberts, and J. Mullin, AOil Adhesion Testing - Recent Results@, Proceedings
of the 19th Arctic and Marine Oil Spill Program Technical Seminar, Environment
Canada, Ottawa, Ontario, pp. 9-27, 1996.
Mackay, D. and W. Zagorski,
Studies of Water-in-Oil Emulsions, Environment Canada Manuscript Report
Number EE-34, Ottawa, Ontario, 100 pp., 1982.
Schramm, L.L. (ed.), Emulsions.
Fundamentals and Applications in the Petroleum Industry, American Chemical
Society, Washington, D.C., p. 386, 1992.
Speight, J.G., The Chemistry
and Technology of Petroleum, Marcel Dekker, Inc., New York, New York, 1991.
Twardus, E.M., A Study to Evaluate
the Combustibility and Other Physical and Chemical Properties of Aged Oils
and Emulsions, Environment Canada Manuscript Report Number EE-5, Ottawa,
Wang, Z., M. Fingas, and K.
Li, "Fractionation of ASMB Oil and Identification and Quantitation of Aliphatic,
Aromatic and Biomarker Compounds by GC/FID and GC/MS", Proceedings of the
16th Arctic and Marine Oil Spill Program Technical Seminar, Environment
Canada, Ottawa, Ontario, pp. 11-44, 1993.
Wang, Z., M. Fingas, M. Landriault,
L. Sigouin, and N. Xu, AIdentification of Alkyl Benzenes and Direct Determination
of BTEX and (BTEX + C3-Benzenes) in Oils by GC/MS@, Proceedings of the
18th Arctic and Marine Oil Spill Program Technical Seminar, Environment
Canada, Ottawa, Ontario, pp. 141-164, 1995.