Crude oil quality control

Ihab Shokry - (A/G - Lab)

Khalda Petroleum Company

01200005910 &01011114408

11/1/2019
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Introduction to crude oil

➢ What is petroleum?
• Petroleum is a complex mixture of hydrocarbons that occur in the
sedimentary rocks in the form of gases (natural gas), liquids (crude
oil), semisolids (bitumen), or solids (wax or asphaltine).
• An underground reservoir that contains hydrocarbons is called
petroleum reservoir and its hydrocarbon contents that can be
recovered through a producing well is called reservoir fluid.

➢ What is crude oil?

• Is a naturally mixture of hydrocarbons (different sized), generally in
the liquid state.

• It may also include compounds of sulfur, nitrogen, oxygen and

metals.

• Inorganic sediment and water may also be present.

• The exact composition depends upon where the oil comes from but
typically, it contains many big molecules.
• Crude oil is composed of the following groups:
• Hydrocarbon compounds.
• Non-hydrocarbon compounds.
• Organometallic compound and inorganic salt (metallic
compound).
• It is refined into diesel, gasoline, heating oil, jet fuel, kerosene, and
literally thousands of other products called petrochemicals.
• Crude oils are named according to their contents and origins,
and classified according to their per unit weight (specific gravity)
• Heavier crudes yield more heat upon burning, but have lower API
GRAVITY and market price in comparison to light (or sweet) crudes.
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• Where did crude oil come from:

• Crude oil is a mixture of hydrocarbons that formed from plants and
animals that lived millions of years ago.
• Crude oil is a fossil fuel, and it exists in liquid form in underground
pools or reservoirs, in tiny spaces within sedimentary rocks, and near
the surface in tar (or oil) sands.
• Crude oil history:
• According to Herodotus, more than four thousand years ago
natural asphalt was employed in the construction of the walls and
towers of Babylon, great quantities of it were found on the banks of
the river Issus.
• In China, petroleum was used more than 2000 years ago. In I Ching,
one of the earliest Chinese writings cites the use of oil in its raw state
without refining was first discovered, extracted, and used in China in
the first century BCE.
• The earliest known oil wells were drilled in China in 347 AD or
earlier. They had depths of up to about 800 feet (240 m) and were
drilled using bits attached to bamboo poles.
• The oil was burned to evaporate brine and produce salt.
• Petroleum was known as burning water in Japan in the 7th century.
• The first streets of Baghdad were paved with tar, derived from
petroleum that became accessible from natural fields in the region. In
the 9th century, oil fields were exploited in the area
• In 1710 or 1711 (sources vary) the Russian-born Swiss physician and
Greek teacher Eirini d'Eyrinys discovered asphaltum.
• In 1745 under the Empress Elizabeth of Russia the first oil well and
refinery were built.
• Pechelbronn oil field was active until 1970, and was the birthplace of
companies like Antar and Schlumberger. The first modern refinery
was built there in 1857.
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• The modern history of petroleum began in the 19th century with the
refining of paraffin from crude oil. The Scottish chemist James
Young in 1847 noticed a natural petroleum .
• In 1875, crude oil was discovered by David Beatty at his home in
Warren, Pennsylvania.
• This led to the opening of the Bradford oil field, which, by the 1880s,
produced 77 percent of the global oil supply.

Petroleum origin:
• Crude oil discovery include two hypotheses :

• Inorganic Hypotheses.
• Organic Hypotheses.
Inorganic Hypotheses
Berthelot theory
• Berthelot assumed that acetylene and many hydrocarbons are formed
due to reaction of carbonic acid and carbonates with alkaline metals,
all this occurs in presence of underground water.
Carbide theory
• Crude oil is formed due to chemical reaction of many metal types of
carbide with underground water in presence of high temperature and
pressure.
• Carbide theory had an experimental evidence include experimental
preparation of many hydrocarbons over chemical lab under the same
condition due to the following:
• Many underground metals react with coal( carbon) at high
temperatures due to the following equations :

4 Al + 3 C Al4C 3 (Aluminum carbide)

Ca + 2 C CaC 2 (Calcium carbide)

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• Carbides then react with water vapors at high temperature , which

result in the formation of hydrocarbons as follows:

Al4C 3 + 12 H2O 4 Al(OH)3 + 3 CH4

Methane

CaC 2 + 2 H2O Ca(OH)2 + C 2 H2

Acetylene
• Reduction of unsaturated hydrocarbons in the presence of catalyst
at high temperature lead to the formation of saturated
hydrocarbons (alkanes) as follows :

Polymerization
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Organic Hypotheses
• Organic hypotheses assumed that crude oil is formed due to
accumulation of hydrocarbons. Hydrocarbons accumulate
naturally, thousands of feet below the surface of the Earth, from
the decomposition of organic materials like plants and marine
animals which died, decomposed and Trapped beneath the ground
under enormous pressure and high temperatures, these
hydrocarbons were compressed and eventually transformed into
crude oil after millions of years.
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Crude oil chemical composition:

• The elementary composition of crude oil usually falls within
the following ranges:
• Carbon 83.0 to 87.0%.
• Hydrogen 10.0 to 14.0 %.
• Sulfur 0.05 to 6.0 %.
• Nitrogen 0.1 to 2.0 %.
• Oxygen 0.05 to 1.5 %.
• Metals 0.00 to 0.14 %.

Hydrocarbons
• Straight chain and branched chain alkanes:

CH3 (CH2 )n CH3 CH3CH2CH2 (CH2 )m CH2CHCH3

CH3

Straight-chain paraffin Branched-chain paraffin

• Alkanes physical state(C1-C4 (Gases), C5-C15 (Liquids) and

C15-C27(Solids)

• Cyclo alkanes

Cyclopentane Cyclohexane Alkylcyclohexane

•
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Unsaturated compounds
CH3 CH3

CH3

Benzene Toluene Xylene

Naphthalene Anthracene

Non hydrocarbons
• Sulfur compounds
RSH RSR RSSR
S
Thiols(Mercaptans) Sulfides Cylclic Sulfide Disulfides

S S S

Thiophene Benzothiophene Dibenzothiophene

• Nitrogen compounds:

N N N N N
H H H
Pyrrol Indol Carbazole Pyridine Quinoline
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• OXYGEN COMPOUNDS:
OH OH
OH

CH3

Phenol Creasols
Naphthols

METTALIC COMPOUNDS
N N

NH N X N
HN

N N

Petroporophyrin Metallic Petroporophyrin

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Types of crude oil

• Crude oil classification: Three types of crude oil are involved as
the following:
Paraffinic
• The ratio of paraffinic hydrocarbons is high compared to aromatics
and naphthenic.
• Crude oil containing a relatively high percentage (by volume) of
linear and branched paraffins.
• Paraffinic crude oils are rich in straight-chain and branched paraffin
hydrocarbons, whereas naphthenic crude oils contain mainly
naphthenic and aromatic hydrocarbons.
• The composition and classification of many crude oils are obtained
by ring analysis and by determination of the other constituents.

Naphthenic
• The ratios of naphthenic and aromatic hydrocarbons are relatively
higher than paraffinic hydrocarbons.
• Naphthenic crude contain relatively little wax. Naphthenic crude
oils contain mainly (by volume) napthenes and other aromatic
hydrocarbons.
• They generally have a lower API gravity, e.g., they are the heavier.
• A crude oil containing less than 50% saturated hydrocarbons and over
40% naphthenic hydrocarbons.
• Cycloalkanes (or Cyclo paraffins), also called napthenes in the
petroleum industry, are saturated hydrocarbons containing structures
with carbon atoms linked in a ring.
• The cycloalkane composition in crude oil worldwide typically varies
from 30% to 60%.
• The predominant monocycloalkanes in crude oil are in the
cyclopentane series, having five carbon atoms in the ring, and in the
cyclohexanes, having a six-membered ring.
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• Paraffin wax produced from crude oil consists primarily of long chain,
saturated hydrocarbons (linear alkanes/ n-paraffins) with carbon
chain lengths of C18 to C75+, having individual melting points from
40 to 70°C.
• This wax material is referred to as “microcrystalline wax.”

Comparison between paraffinic and naphthenic crude

Asphaltic
• Contains large amount of polynuclear aromatics, high asphaltene
content and relatively less paraffin's than paraffinic crude.
• Asphaltene are molecular substances that are found in crude oil, along
with resins, aromatic hydrocarbons, and saturates (i.e. saturated
hydrocarbons such as alkanes).
• The word "asphaltene" was coined by Boussingault in 1837 when he
noticed that the distillation residue of some bitumen had asphalt-like
properties.
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• Asphaltene consist primarily of carbon, hydrogen, nitrogen, oxygen,

and sulfur, as well as trace amounts of vanadium and nickel.
• The C: H ratio is approximately 1:1.2, depending on the asphaltene
source.
• Asphaltene are defined operationally as the n-heptane (C
insoluble, toluene soluble component of a carbonaceous material such
as crude oil.

Crude oil quality parameters

Standard code
S/N TEST
ASTM
1 API Gravity of crude oil @ 60 º F D 1298 & d287
2 BS&W % volume D4007
3 Water content % volume D4006
4 Salt content @ crude oil PTB D3230
5 Pour point ºC D 97
6 Flash point test closed cup D93
7 Viscosity kinematics D445
8 Reid vapor pressure (R.V.P) D323
9 Saybolt Universal Second(SSU)
10 Water Content in pet products KARL FISCHER
11 Oil in water AMOCO
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Test NO (1)
API Gravity of crude oil @ 60 º F

Standard code
ASTM D 1298 & d287

• The American Petroleum Institute gravity, or API gravity, is a measure

of how heavy or light a petroleum liquid is compared to water: if its
API gravity is greater than 10, it is lighter and floats on water; if less
than 10, it is heavier and sinks.
• API gravity is thus an inverse measure of a petroleum
liquid's density relative to that of water (also known as specific
gravity).
• It is used to compare densities of petroleum liquids. For example, if
one petroleum liquid is less dense than another, it has a greater API
gravity.
• API gravity values of most petroleum liquids fall between 10 and 70
degrees.
• DENSITY is the mass per unit volume at 15C and 14.696 PSI.
• Relative density is the Density of petroleum Fraction / density of
water at the same temperature.
• Relative density is the mass of a given volume of liquid at specific
temperature to the mass of equal volume of pure water at the same or
different temperature; both reference temperatures shall be stated.

API gravity formulas

• API gravity is calculated using the specific gravity of oil, which is
nothing more than the ratio of its density to that of water.
• Specific gravity for API calculations is always determined at 60
degrees Fahrenheit (crude oil from 15 to 45 API).
• The formula to calculate API gravity from Specific Gravity (SG) is:
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• Conversely, the specific gravity of petroleum liquids can be derived

from their API gravity value as:

• Using API gravity to calculate barrels of crude oil per metric ton
• Barrels of crude oil per metric ton = API gravity +131.5 /(141.5*0.159)

• API gravity affects crude oil pricing, storage conditions and oil
custody transfer.

• Classification of Crude Oil API Gravity

• Light crude oil has an API gravity higher than 31.1° (less than
870 kg/m3)
• Medium oil has an API gravity between 22.3 and 31.1° (i.e., 870 to
920 kg/m3)
• Heavy crude oil has API gravity below 22.3° (i.e., 920 to 1000 kg/m3).
• Extra heavy oil has an API gravity below 10.0° (i.e., greater than
1000 kg/m3).
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API GRAVITY ASTM (D1298)

Scope of work:

• To determine relative density (specific gravity) & density or API

gravity of crude petroleum, petroleum products or mixture of
petroleum and non-petroleum products normally handled as liquids
with R.V.P= 14.6 psi or less by means of glass hydrometer.
• Measured values on hydrometer either at the reference temperature
or@ another convenient temperature and readings corrected to
reference temperature by means of petroleum measurement tables.
• Values obtained at other than the reference temperature being
hydrometer readings not density measurement.
Terminology:

• Pour point: lowest temperature at which test portion of crude oil or

petroleum product will continue to flow when cooled under specific
conditions.
• Cloud point: temperature at which cloud of wax crystals first appears
in a liquid when it cools under specific conditions.
• Wax appearance temperature: temperature at which wax solids form
when crude oil or petroleum product cools under specific conditions.
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• Summary of test method :

• Sample is brought (cooled) to specified temperature.
• Tested sample is transferred to hydrometer cylinder (both tested
sample and hydrometer brought to the same temperature).
• Hydrometer is lowered into the tested sample and allowed to settle.
• After temperature equilibrium has been reached, hydrometer scale is
read and temperature of the tested sample is observed.
• Observed hydrometer reading is reduced to the reference T by means
of petroleum measurement tables.
• If necessary hydrometer cylinder and its contents are placed in a
constant temperature bath to avoid excessive temperature variation
during test.
• Test significance :
• API gravity is a factor governing the quality and pricing of crude
petroleum.
• Storage condition.
• Accurate determination of relative density (specific gravity), or API
gravity of petroleum and its products necessary for the conversion of
measured volumes to volumes or masses, or both, at the standard
reference temperatures during custody transfer.
• (APPARATUS)
• Hydrometer: Glass hydrometer graduated in units of
• *Density * Relative density *API gravity
• Thermometer: having range, graduation intervals and maximum
permitted Scale error (as reference in petroleum tables).
• Hydrometer cylinder : clear glass, plastic or metal but the inside
diameter of cylinder shall be at least 25mm greater than outside
diameter of the hydrometer , height should be the such that the
appropriate hydrometer floats in the tested sample with at least 25
mm clearance between the bottom of the hydrometer and the bottom
of cylinder.
• Hydrometer cylinder shall not affect the sample being tested.
• Constant temperature Bath: for temperature control system.
• Stirring rod (glass & plastic) (400 ml in length)
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• Sampling
• Samples of volatile crude petroleum or petroleum products are
preferably taken by Practice D 4177, using a variable volume (floating
piston) sample receiver to minimize any loss of light components
which may affect the accuracy of the density measurement. In the
absence of this facility, extreme care shall be taken to minimize these
losses, including the transfer of the sample to a chilled container
immediately after sampling.
• Sample Mixing—may be necessary to obtain a test portion
representative of the bulk sample to be tested, but precautions shall
be taken to maintain the integrity of the sample during this operation.
Mixing of volatile crude petroleum or petroleum products containing
water or sediments, or both, or the heating of waxy volatile crude
petroleum or petroleum products may result in the loss of light
components.
• Volatile Crude Petroleum and Petroleum Products Having an RVP
Greater than 50 kPa—Mix the sample in its original closed container
in order to minimize the loss of light components.
• Mixing volatile samples in open containers will lead to loss of light
components and consequently affect the value of the density
obtained.
• Waxy Crude Petroleum—If the petroleum has a pour point above
10°C, or a cloud point or WAT above 15°C, warm the sample to 9°C
above the pour point, or 3°C above the cloud point or WAT, prior to
mixing. Whenever possible, mix the sample in its original closed
container in order to minimize the loss of light components.
• (Procedure)
• Bring the hydrometer cylinder and thermometer.
• Transfer the sample to hydrometer cylinder without splashing to
avoid formation of air bubbles and minimize vaporization of lower
boiling components of more volatile samples.
• Remove any air bubbles formed and located on the surface of the
tested sample by touching with a piece of clean filter paper before
inserting hydrometer.
• Place the cylinder containing the tested sample in vertical position in
allocation where the temperature of the surroundings does not change
more than 2C during the taken time to complete the test.
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• Use a constant temperature bath to maintain constant T through test

operation where T of the surroundings differs by more than 2C.
• insert appropriate thermometer or T measurement device and stir the
tested sample with stirring rod to keep uniform T through test
• Record the temperature of the sample to the nearest 0.1 and remove
the thermometer and stirring rod from hydrometer cylinder.
• Lower the hydrometer into the liquid and release when apposition of
equilibrium is reached (make sure that hydrometer floats freely).
• Allow sufficient time for hydrometer to come to rest and for all air
bubbles to come to surface (remove any air bubbles before reading)
• 10-When the hydrometer has come to rest floating freely away from
the walls of the cylinder read the hydrometer scale reading.
• Immediately after recording the hydrometer scale reading, carefully
lift the hydrometer out of the liquid then insert thermometer or T
measurement device and stir the sample with glass rod & if you could
not obtain constant T maintain temperature bath.
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• Calculation
• Apply temperature correction of the thermometer.
• Record the corrected hydrometer scale readings to nearest 0.1 kg/m3 in
density or relative density or 0.1API.
• To convert density from KG/m3 to kg/L divide by 1000.
• Use petroleum tables to obtain API.

• Precision and Bias

• Precision—The precision of the method as determined by statistical
examination of interlaboratory results is as follows:
• Repeatability—The difference between two test results, obtained by
the same operator with the same apparatus under constant operating
conditions on identical test material, would in the long run, in the
normal and correct operation of the test method, exceed the values in
Table 1 only in one case in twenty.
• Reproducibility—the difference between two single and independent
results obtained by different operators working in different
laboratories on identical test material would, in the long run, in the
normal and correct operation of the test method, exceed the following
values in table 1 only in one case in twenty.
• Bias for this test method has not been determined. However, there
should be no bias from absolute measurements, if the calibration of
the hydrometer and the thermometer is traceable to International
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Standards, such as supplied by the National Institute of Standards

and Technology.
Table 1
R=Repeatability In the normal and correct Operation of the test
method, exceed 0.2° API only in one case in twenty.
Z=Reproducibility In the normal and correct operation of the test
method, exceed 0.5° API only in one case in twenty.

Statistical bias is a feature of a statistical technique or of its results

whereby the expected value of the results differs from the true
underlying quantitative parameter being estimated.

API
‫ هي مقياس للتعبير عن كثافة الزيت النسبية عموما في صورة‬API ‫وذلك الن كثافة الزيت النسبية عموما‬
‫ لذلك إلظهار القيمة بشكل اوضح او لتكبيرها‬0.797‫ و‬0.741‫ و‬0.732 ‫الفرق بينها يكون ضئيل جدا مثال‬
.‫تكون في صورة‬API
• We also need volume correction for example 1000 bbl. @60F when
transferred to another place @90F.
• SO the amount decreases because of vaporization of oil light
component and vice versa from 60F to 40F. AMOUNT WILL
INCREASE SO WE NEED VOLUME CORRECTION
***Any increase in API gravity corresponds to decrease in SP.GR.

Test NO (2)
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BS&W % volume (By centrifuge method)

Standard code
D4007

• Basic sediment and water (BS&W) is a technical specification of

certain impurities in crude oil.
• When extracted from an oil reservoir, the crude oil will contain some
amount of water and suspended solids from the reservoir formation.
• The particulate matter is known as sediment or mud.
• The water content can vary greatly from field to field, and may be
present in large quantities for older fields, or if oil extraction is
enhanced using water injection technology.
• The bulk of the water and sediment is usually separated at the field
to minimize the quantity that needs to be transported further.
• The residual content of these unwanted impurities is measured as
BS&W.
• Oil refineries may either buy crude to a certain BS&W specification
or may alternatively have initial crude oil dehydration
and desalting process units that reduce the BS&W to acceptable limits
• The BS&W of a fluid hydrocarbon measures free water, sediment, and
oil emulsion as a volume percentage.
• Water cut meter measures the water content (cut) of crude oil and
hydrocarbons as they flow through a pipeline. While the title "Water
cut" has been traditionally used, the current API naming is OWD or
On-Line Water Determination. The API and ISO committees have not
yet come out with an international standard for these devices but
there are however standards in place for fiscal automatic sampling of
crude oil namely API 8.2 and ISO 3171.
• Water cut meters are typically used in the petroleum industry to
measure the water cut of oil flowing from a well, produced oil from a
separator, crude oil transfer in pipelines and in loading tankers.
• There are several technologies used. The main technologies are
dielectric measurements using radio or microwave frequency and NIR
measurements and less common are gamma ray based instruments.
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• The water cut is the ratio of water produced compared to the volume
of total liquids produced from an oil well. The water cut in water
drive reservoirs can reach very high values.

• Oil with significant water content >5% do not represent the properties
of dry oil.

• Crude oils entering transmission pipelines contain <0.5% Basic

Sediments & Water (BS&W).

• Scope of work:
• To determine water and sediment in crude oil by means of
centrifuge procedure.
• This centrifuge method is not satisfactory because the amount of
water detected is almost lower than actual water content.
• When highly accurate value is required, the revised procedures for
water by distillation (D4006) and sediment by extraction (D473) is
used.
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• Significance and use:

• It can cause corrosion of equipment.
• It can cause problems in processing.
• Determination of water and sediments is required to measure
accurately net volumes of actual oil.
• Summary of test method:
• Equal volumes of crude oil and water-saturated tolouene (tolouene
–xylene- kerosene) are placed in a cone or pear shaped centrifuge
tube.
• After centrifugation, volume of higher gravity water and sediments
layer at the bottom of the tube a read.
• Apparatus &Chemicals:
• Centrifuge:
• A centrifuge capable of spinning two or more filled cone-shaped,
203-mm (8-in.) centrifuge tubes at a speed that can be controlled to
give a relative centrifugal force (rcf) of minimum of 600 at the tip of
the tubes shall be used.
• All equipment’s shall be soundly constructed to withstand the
maximum centrifugal force capable of being delivered by the
power source.
• The centrifuge shall be enclosed by a metal shield or case strong
enough to eliminate danger if any breakage occurs.

• The centrifuge shall be heated and should be controlled

thermostatically to avoid unsafe conditions.

• It should be capable of maintaining the sample temperature

during the entire run at 60 6 3°C (140 6 5°F).
• Electric powered and heated centrifuges must meet all safety
requirements for use in hazardous areas.
• Calculate the speed of the rotating head in revolutions per minute
(r/min) as follows:
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• Centrifuge Tubes—each centrifuge tube shall be a 203-mm (8-in.)

cone-shaped tube, conforming to dimension given in Fig. 1 and
made of thoroughly annealed glass.
• The graduations, numbered as shown in Fig. 1, shall be clear and
distinct, and the mouth shall be constricted in shape for closure
with a cork.
• Scale error tolerances and the smallest graduations between
various calibration marks are given in Table 1 and apply to
calibrations made with air-free water at 20°C (68°F), when reading
the bottom of the shaded meniscus.
• Bath—the bath shall be either a solid metal block bath or a liquid
bath of sufficient depth for immersing the centrifuge tube in the
vertical position to the 100-mL mark.

• Means shall be provided for maintaining the temperature at 60 6

3°C (1406 5°F).
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• Chemical reagents
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• Tolouene (water saturated) or xylene.

• Kerosene. (More than one chemical structure ranges from C12H26 to
C15 H32).
• Demulsifier: for making water separation more easily.
• The recommended Stock solution is 25 % Demulsifier to 75 % toluene.
For some crude oils a different ratio of Demulsifier to toluene may be
required.
• Demulsifier used in the concentration and quantity recommended
will not add to the water and sediment volume determined.
• Sampling
• Sampling is defined as all steps required to obtain analiquot of the
contents of any pipe, tank, or other system and to place the sample
into the laboratory test container.
• Procedure
• Fill each of two centrifuge tubes to 50-ml mark with sample directly
from sample container.
• Add 50ml of tolouene- xylene or kerosene.
• Add 0.2ml of Demulsifier solution to each tube using 0.2ml pipet.
• In case of viscous oil, (mixing of oil with solvent should be very
difficult so solvent may be added to centrifuge tube first to facilitate
mixing).
• Loosen the stoppers slightly and immerse the tubes to 100 ml mark
for at least 15 min in a bath maintained @60C + or –3.
• Secure the stoppers and invert tubes ten times to ensure uniform
mixing of oil and solvent.
• Place the tubes in the cups on opposite sides of centrifuge tubes to
establish balanced conditions.
• Immediately after centrifuge tubes come to rest read and records the
combined volume of water and sediments at the bottom of each tube.
• Return the tubes without agitation to the centrifuge and spin for
another 10 mins at the same rate.
• Repeat this operation until the combined volume of water +
sediments remains constant for two consecutive readings.
• (Same temperature be maintained)Avoid danger of tubes breaking in
the cups.
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• Calculation
• Record final volume of water and sediments in each time after
readings are constant (fixed).
• If difference between two readings repeat again.
• Multiply final constant volume *2 to obtain total water and sediment
percentage in each sample as %
• For example:
• If final recorded volume on tube is 3% so final B.S&W %= 3*2=6%

• REPEATABILITY &REPRODUCIBILITY

R= Repeatability in the long run, in the normal and correct operation of the test method,
exceed the following value in only one case in twenty:
From 0.0 % to 0.3 % water, see Fig3
From 0.3 % to 1.0 % water, repeatability is constant at 0.12.
Z= Reproducibility in the normal and correct operation of the test method, exceed the
following value in only one case in twenty:
From 0.0 % to 0.3 % water, see Fig. 3.
From 0.3 % to 1.0 % water, reproducibility is constant at 0.28.

Measuring emulsified water procedure

• Shake the bottle and take 100 ml sample in A B.S & W% centrifuge
tube.
• Put the centrifuge tube on a stand for about 10 sec and observe result.
• Put the tube inside the centrifuge for 30 sec ( time may be variated
depending on retention time of process vessels ) ( result 1)
• Take the centrifuge tube and add 2-3 drops from demulsisifer and
shake.
• Put the tube inside the water bath for 15 minutes then the centrifuge
for 10 mins and record result (result 2).

Emulsified water = Result 2-Result 1

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Test NO (3)
Salt content of crude oil

Standard code
D3230

Scope of work:
1. To determine approximate chloride salts concentration in crude oil.
2. Range of concentration covered is (0-500) mg/Kg or (0-150) lbs.
/1000bbls as chloride concentration / volume of crude oil.
3. This test method measures conductivity in the crude oil due to the
presence of common chlorides such as: NaCl 70%&CaCl2 10% and
MgCl2 20% other conductive materials may be also present.
Values stated in SI units (international system units) regarded as
standard (acceptable solution concentrations) g/m3 or P.T.B.

• The salt content of crude oil almost always consists of salt dissolved
in small droplets of water that are dispersed in the crude.
• Salts in crude oil: commonly chlorides of sodium, calcium and
magnesium are present in crude oil; other inorganic chlorides may be
also present.
• **P.T.B=1bs/1000bbls
• **1m3 crude=6.237 bbl.

Significance and use:

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** Knowledge of chloride salts content is important in deciding whether

the crude oil needs desalting.

**Excessive chloride in crude can cause:

• Higher corrosion rates in refining units.

• Effect on catalysts used in these units.
• Effect on general specs and crude oil price.

• Apparatus:

1. Test beaker.
2. Pipet 10ml.
3. Cylinder 100 ml, stoppered.
4. Other volumetric and graduated pipets and volumetric flasks should
be available.
5. Control unit: salt analyzer Capable of producing and displaying
several voltage levels for applying stress to a set of electrodes
suspended in a beaker containing a test solution.

Reagent & Materials

• Purity of reagents: all reagents shall confirm to the specifications of
the American chemical society.
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• Type II grade of reagent water shall be prepared by

distillation using a still designed to produce a distillate
having a conductivity of less than 1.0 μS/cm at 298 K (25°C).
Ion exchange, distillation, or reverse osmosis and organic
adsorption may be required prior to distillation if the purity
cannot be attained by single distillation.
• Mixed alcohol solvent: mix 63-volumes of 1-butanol and 37- volumes
of absolute methyl alcohol (anhydrous) to each liter of this mix add
3ml of water.
• Xylene.

Calibration process required the following

• Magnesium &calcium and sodium chlorides.
• Refined or neutral oil (chloride free oil).
• Salts (mixed solution) concentrated and diluted solution.
• Purity of water is also important.

Sampling
• Ensure that the sample completely homogenized with a suitable
mixer.
• Sample of very viscous material may warmed until they are
reasonably fluid before they sampled.
• No sample shall be heated more than is necessary to lower the
viscosity.
• Presence of water and sediment will influence the conductivity of the
sample.
Apparatus preparation
• Support apparatus on a level, steady surface (keep stable).
• Prepare apparatus for operation in accordance with instructions for
calibrating, checking and operating the equipment.
 30

• Clean and dry all parts of test beaker, the electrode and its accessories
before starting the test, being sure to remove any solvent that had
used to clean the apparatus.
Procedure
• Add 15 ml of xylene to dry 100 ml graduated, glass stoppered cylinder.
• Pippet 10ml of the crude oil sample.
• Rinse the pipet with xylene until free of oil.
• Make up to 50 ml with xylene, stopper and shake the cylinder very
well for approx. 60 secs.
• Dilute to 100ml with mixed alcohol solvent and again shake
vigorously for approx. 30secs.
• Allow the solution to stand for approx.5mins, pour it into the dry test
beaker.
• Obtain voltage and current readings (place electrodes into the solution
in the beaker, making sure that the upper edge of the electrode plates
are below the surface of the solution.(adjust the indicated electrode
voltage to a series of values for examples 25,50,125,200 and 250, at each
voltage note the current reading and record the voltage displayed and
current.
• Remove the electrodes from the solution, rinse with xylene followed
by naphtha and then allow drying.
• Clean the apparatus.

Calculations
• Subtract the values obtained for blank measurement from the values
obtained from the sample measurement to obtain the net current
reading of the sample.
• Read the indicated salt concentration correspond to net current (ma
reading of sample from calibration tables).

Blank sample measurement

 31

1. For measuring blank sample, we can use either (10ml neutral oil
+40ml xylene +50 ml alcohol) or we can use (50ml xylene+50 ml mixed
alcohol)
2. This to help in reading accurately salts in our crude and to make sure
that mixed alcohol solvent free of high water content.
3. Conducting of mixed alcohol >0.25Ma @125V so high water content in
alcohols we should eliminate.

4. Blank measured when preparing alcohols.

Report
• Report concentrations directly in mg/m3 or 1bs/1000bbls

Salt in crude calibration (ASTM D3230)

Reagent & Materials
• Purity of reagents: all reagents shall confirm to the
specifications of the American chemical society.
• Mixed alcohol solvent: mix 63-volumes of 1-butanol and 37-
volumes of absolute methyl alcohol (anhydrous) to each liter
of this mix add 3ml of water.
• Xylene.
Calibration process required the following
• Magnesium &calcium and sodium chlorides
• Refined or neutral oil (chloride free oil)
• Salts(mixed solution) concentrated and diluted solution
• Purity of water is also important.
PROCEDURE
Calibration
 32

Required chemicals
1CaCl2&MgCl2 and NaCl(10g/l): transfer 1(+or-0.01)gm. of each
one OR equivalent weight of hydrated salt into 100ml
volumetric flask and dissolve in 25ml of water then dilute to
mark with mixed alcohol solvent.
2. Any refined crude-free oil of approximately 10ml (neutral
oil).
3. Combine 10ml of CaCl2 solution, 20ml of MgCl2 solution and
70ml of NaCl solution and mix all thoroughly so we obtain
concentrated solution (mixed solution conc).

4. Transfer 10ml of the concentrated mixed solution into 1000ml

volumetric flask and dilute to mark with mixed alcohol solvent.

5. Solution conductivity affected by temperature so T of the

tested sample at the time of measurement should be within 3C
of the temperature at which calibration curves made.
6. Blank measurement when exceeding 0.25 m/a so water or
another conductive impurity is present and its source must
found and eliminated before calibration.
7. Determine blank measurement at each time fresh xylene or
mixed solvent is used.
 33

Mixed salt solution (concentrated)

Transfer 10ml of the concentrated mixed solution into
volumetric flask 1000 ml and dilute to mark with mixed alcohol.
 34

Mixed salt solution (diluted)

• 1-In a dry 100-ml graduated, glass stoppered mixing cylinder:

1- Add 15ml of xylene+10 ml of neutral oil.
2- Rinse pipet with xylene until free of oil then make up to
50 ml with xylene.
3-Stopper and shake vigorously for 60 secs to affect
solution.
4- Add quantity of dilute mixed salt solution (appropriate
to the salt content measured).
5-Dilute to 100 ml with mixed alcohol solvent.
6-Shake cylinder for 30 secs and allow to stand for 5mins,
pour solution into dry test beaker.
7-Place electrodes into solution in beaker (upper edge of
the electrode plates are below the surface of the solution).
8- Adjust indicated electrode voltage to series of values for
ex 25, 50,125,200 V &and at each voltage note current
reading and record voltage displayed and current to nearest
0.01ma.
9-Repeat again using other volumes of mixed salt solution.
10-Substract obtained values for the blank measurement
from the indicated current and plot chloride content against
the net current for each voltage.
 35

• A desalter is a process unit that removes salt from the crude oil. The
salt is dissolved in the water in the crude oil, not in the crude oil itself.
The salt content after the desalter is usually measured in PTB pounds
of salt per thousand barrels of crude oil.
• Desalting also removes suspended solids such as sand, dirt, and rust
particles picked up in transport. In the desalter, the crude oil is heated
and then mixed with 5-15% volume of fresh water so that the water
can dilute the dissolved salts.
• The oil-water mix is put into a settling tank to allow the salt-
containing water to separate and be drawn off. Frequently, an electric
field is used to encourage water separation. Demulsifying chemicals
are also used. For high levels of salt and/or to achieve very low final
concentrations, two- or three-stage desalting may be used.

• After primary oil/water separation, there is often a small amount of

unwanted salts in residual water in the crude oil that needs to be
reduced to a concentration around 5-10 PTB (Pounds per Thousand
Barrels) salt. This salt needs to be removed. Crude Oil Desalting
technology is utilized to remove residual salt.
 36

• . Depending on the downstream process, a limit of between 1- 10 PTB

of salt is usually specified which can require additional treatment
beyond dehydration. A Desalter unit can perform this. Clean dilution
or wash water is injected into the crude oil feed to the Desalter
through a mixing device to dilute the brine to a level where the target
salt content can be achieved by the downstream Dehydration unit. In
difficult applications, this wash water can be recovered and recycled
in a 2-stage dehydration and desalting process.
R= Repeatability In the normal and correct operation of the test method, exceed the
following values in one case in twenty.
r (mg/kg) = 0.3401 X 0.75
r (lbs./1000) bbls= 0.2531 Y0.75
where:
X = the average of two test results in mg/kg, and
Y = the average of two test results in lbs. /1000 bbls (PTB).
Z= Reproducibility In the long run, exceed the following values in only one case in twenty.
R =(mg/kg) =2.7803 X0.75
R =(lbs./1000 bbls) = 2.069 Y0.75
where:
X 5 the average of two test results in mg/kg, and
Y 5 the average of two test results in lbs. /1000 bbls (PTB).

Test NO (4)
 37

Pour point OF CRUDE OIL ºC

Standard code
ASTM D97
Scope of work:
• This test method is used for any petroleum products (especially
designed for crude oil).
• Procedure is suitable for black specimens, non-distillate fuel oil.
• Used for fluidity of residual fuel at specified temperature.

Pour point significance:

• Pour point specially designed for crude oils.
• Helps to determine least limit of flow and in transportation.
• The maximum and minimum pour point temperature provide
temperature window where crude oil might appear in the liquid state
as well as the solid state (depending on its thermal history).
• Monitor the flow behavior of crude oil (for certain applications).
• It is especially useful for the screening of the effect of wax
interaction modifiers on the flow behavior of crude oils.
Terminology:
Pour point: the least temperature at which liquid becomes semi solid
and lose its flow characteristic, higher pour point associated with a
high paraffin wax content( this factor affects pour point).
• It is the lowest temperature at which the oil will pour or flow when it
is cooled, without stirring, under standard cooling conditions. Pour
point represents the lowest temperature at which oil is capable of
flowing under gravity.
• When the temperature is less than the pour point of a petroleum
product, it cannot be stored or transferred through a pipeline.
• High crude oil pour point reflects bad need to PPD injection and bad
need of heater- treater of high temperature to avoid crude oil plugging
in pipelines or shipping tanks.

Summary of test method:

 38

• After primary heating, the sample is cooled at specified rate and

examined at intervals of 3C for flow characteristics.
• The lowest temperature at which movement of sample is observed is
recorded as the pour point.

Apparatus:
• Test jar: cylindrical, made of clear glass, flat bottom (33.2-34.8 mm
outside diameter and 115-125mm in height). Inside diameter of jar can
range from 30-32.4 mm.
• Thermometer: Have definite ranges of temperature.
• Cork (‫)فلين‬: to fit the test jar, bored centrally for the test thermometer.
• Jacket: cylindrical, metal, flat bottomed 115+ or-3 mm depth with
inside diameter 44.2 to 45.8 mm (vertical position in the cooling bath).
• Disk or cork: to fit loosely inside the jacket.
• Gasket: may be made of leather, rubber to fit around the outside of
the test jar and loosely inside the jacket.
• Bath or baths: (maintained @prescribed temperatures).

‫ كلوريد كالسيوم)أو ثالجة قياس نقطة االنسكاب‬, ‫ كلوريد صوديوم‬, ‫حوض التبريد (يستخدم ثلج‬
Reagent &materials: different solvent may be used for low T bath
Pour Point refrigerator
media such as acetone, alcohol and so only.

Procedure
 39

• Heat the sample into water bath until it is just sufficiently fluid to
pour into the test jar.
• Pour the tested sample into the test jar to the level mark when
necessary.
• Immediately close the jar with the cork carrying cloud, pour
thermometer.
• In case of high pour points >36C use higher range thermometer.
(adjust position of cork& thermometer)
• Thermometer is immersed (capillary being 3mm below the surface of
the sample).
• Reheat the sample to 45-48˚C (113-118˚F). As soon as the test specimen
has reached the required temperature, remove the cork carrying the
thermometer and stir the test specimen gently with a spatula or
thermometer.
• Remove the test jar from the water bath and dry the test jar.
• Place the gasket on the test jar.
• Let it stand until reach 90˚F.
• Insert the jar into the cooling jacket 0˚C.
• Examine the sample every 5˚F interval as follow:
• Remove the test jar from the jacket.
• Tilt the jar just enough to ascertain whether there is movement of the
test specimen in the jar or not.
• When the movement observed, immediately return the test jar into the
jacket.
• The complete operation of removal and replacement shall require not
more 3 seconds.
• If the test specimen showed any movement, replace the test jar into
the jacket and repeat the test for flow at the next reading.
• If the sample reaches 45˚F, transfer the jar in to another cooling jacket
-18˚C.
• Continue in this manner until the point reached at which the test
specimen shows no movement when the test jar is held in a horizontal
position for 5 seconds.
• Record the observed reading.
• The Pour point is above this reading with +5˚F.
• Experimental precautions to be considered:
 40

• Make sure that disk, gasket and inside of the jacket are clean and dry.
• Place the disk in the bottom of the jacket.
• Place the gasket around the test jar, 25mm from the bottom.
• Insert the test jar in the jacket (never place a jar directly into the
cooling medium).
• After the tested sample has cooled to allow paraffin wax crystals
formation take care:
• Do not disturb the mass of the tested sample.
• Do not permit the thermometer to shift in the sample. (Any disturb
will affect network of wax crystals and lead to wrong results).
• Pour point are expressed in integers that are positive or negative
multiples of 3C or 5F so:
• Begin to examine the appearance of the tested sample when the
temperature is 9C above the expected pour point.
• At each thermometer reading (multiple of 3C below the starting
temperature) remove the test jar from jacket.
• Tilt the test jar enough to ascertain whether there is movement of the
sample in the test jar.
• Important note: the complete operation of removal and replacement
shall require not more than 3 secs.
• If the sample has not ceased or stop flowing when its temperature 27C
transfer the test jar to the next lower temperature bath.
• As soon as the sample in the test jar does not flow when tilted, hold
the jar in a horizontal position for 5secs (noted accurate timing
device).
• samples of residual fuels, black oil which have been heated to T
higher than 45C during preceding 24 hours shall kept at room
temperature for 24h before testing( ‫في حالة عدم تأثر العينة بتغير درجة الحرارة ال يتم‬
)‫ ساعة‬24 ‫تركها لمدة‬
• Cooling jacket should be dry, flat bottomed, and has the dry disk fit
loosely inside it. If the disk is wet, it should be dried then placed in
the jacket for at least 10-15 minutes before using it in the test.

Sampling precautions:
 41

• The samples contains volatile material, hence loss by evaporation can

occur.
• The samples contain water and sediment tends to separate in the test
jar.
• If the crude samples are to be tested for API, RVP or other tests can
lose light ends, subsample for these tests shall be taken first.
• Sample container should be heated to complete melting for high
melting point paraffin stick on the inner wall and to be
homogenously suspended in the sample.
• If the crude sample stored at low temperature below their cloud point
for 6 hours, it will show wax deposited on the inner wall of the
sample. The wax deposited is the high melting point wax and it will
affect pour point. So heating to re-dissolve and disperse this wax is
crucial for obtaining reliable PPT.
• In order to achieve complete solubility of the wax, heat the sample but
not above 60˚C.
• The proper means and effectiveness of mixing in order to achieve
homogeneity depend on the capacity and shape if sample container.
• Plastic container is not recommended because during heating, it may
rapture and response for heating is weaker than metal cans. Also, it
will not retain gases or light material and cannot be heated without
deformation.
• Sampling:
Sampling: is defined, as all steps required obtaining a portion of the
contents of any pipe, tanks, or other system into a laboratory test
container.
• It is essential that the sample received is representative.

Calculation and report:

Add 3C or 5F to the thermometer recorded in the previous step and
report the result as the pour point.
Repeatability & reproducibility
• 3C (5F) in one case in twenty&6C (10 F) IN ONE CASE IN TWENTY.
 42

• Manual pipeline sampling:

• Procedure:
• Adjust the valve from the sampling probe so that a steady stream is
drawn from the probe.
• Whenever possible, the rate of sample withdrawal should be such that
the velocity of liquid flowing through the probe is approximately
equal to the average linear velocity of the stream flowing through the
pipeline.
• Install cap over sample container.
• Label the sample and transfer it to laboratory.
• spot sample technique:
• It is used for storage tanks has RVP less than 14.7psi
• Procedure:
• Inspect the jar sample container for cleanness, and use only clean and
dry equipment.
• Insert the cork in the sampling bottle.
• Lower the sampling jar to the required location.
• At the required location, pull out the stopper with sharp jerk of the
sampling line.
• Allow sufficient time for the bottle/beaker to completely fill in the
required location.
• Withdraw the jar assembly.
• Verify that the jar is completely filled. If not, discard the jar and start
over again.
• The above steps are for spot sample.
• For composite sample, pour the jar in ¼ of the sample container.
• Repeat the above steps for another depth (location).
• Install cap over sample container.
• Label the sample and transfer it to laboratory.
• Check the refrigerator status and all its connections & methanol level
before allowing test procedure.
• Specimens Having Pour Points Above − 33°C—Heat The specimen
without stirring to 9°C above the expected pour point, but to at least
 43

45°C, in a bath maintained at 12°C above the expected pour point, but
at least 48°C.
• Specimens Having Pour Points of − 33°C and Below—Heat the
specimen without stirring to 45°C in a bath maintained at 48°C and
cool to 15°C in a water bath maintained at 6°C.

• Test NO (5)
Water in crude oil by distillation

Standard code
ASTM D4006

• Scope of work:
• This test method covers the determination of water in crude oil by
distillation.
• Summary of test method :
• The sample is heated under reflux conditions with a water immiscible
solvent which co-distills with the water in the sample. Condensed
solvent and water are continuously separated in a trap—the water
settles in the graduated section of the trap, and the solvent returns to
the distillation flask.
• Significance and Use
• Knowledge of the water content of crude oil is important in the
refining, purchase, sale, or transfer of crude oils.

Apparatus
• Glass distillation flask 1000 ml round bottom flask fitted with a 24/40
female taper joint shall be used..
 44

• Condenser a 400-mL Liebig condenser. A drying tube filled with

desiccant (to prevent entrance of atmospheric moisture) is placed on
top of the condenser.
• Graduated glass trap (24/40 female taper joint).
• Heater. Any suitable gas or electric heater that can uniformly
distribute heat to the entire lower half of the flask may be used. An
electric heating mantle is preferred for safety reasons.
Procedure
1- The sample size shall be selected based on the expected water content
as the following table:
Expected water content volume % Approximate sample size ml

50.1 -100 5
25.1-50 10
10.1-25 20
5.1-10 50
1.1-5 100
0.5-1 200
Less than 0.5 200
2- Add sufficient volume of xylene to the flask to make the total volume
400 ml.
3- Stir well with magnetic stirrer.
4- Assemble the apparatus as shown in figure 1.
5- Apply heat slowly during the initial stage of distillation (approx. half
an hour to one hour) to prevent bumping and then raise the rate of
heating slowly.
6- Continue distillation until no water is visible at any part of the
apparatus except in the trap and the volume of water in the trap
remains constant for 5 min.
7- Let it cool to room temperature. And record the volume to the nearest
0.025 ml.

Important precautions:
 45

• Take care to pour the sample slowly into the graduated cylinder to
avoid entrapment of air and to adjust the level as closely as possible to
the appropriate graduation.
• The precision of this method can be affected by water droplets
adhering to surfaces in the apparatus and therefore not settling into
the water trap to be measured. To minimize the problem, all apparatus
must be chemically cleaned at least daily to remove surface films and
debris which hinder free drainage of water in the test apparatus.
 46

• Distillation is the process of separating the components or substances

from a liquid mixture by using selective boiling and condensation.
Distillation may result in essentially complete separation.
• Distillation is a widely used method for separating mixtures based on
differences in the conditions required to change the phase of
components of the mixture. To separate a mixture of liquids, the
liquid can be heated to force components, which have different
boiling points, into the gas phase. The gas is then condensed back
into liquid form and collected.
 47

• Lab simple distillation:

• The condenser is located at the top of the distillation column and

removes energy from the distillation column. The purpose of the
condenser is to condense the vapor leaving the top tray of the column.
• All apparatus must be chemically cleaned to remove any
contamination or films, which may inhibit drain of water to the trap.
• Check no leakage in all joints in the apparatus.
• Drying tube should fill with desiccant to prevent entrance of
atmospheric moisture.
• Water cooled condenser: exchange heat by removing heat from one
fluid and transferring it to another fluid. A water-cooled condenser is
a heat exchanger that removes heat from refrigerant vapor and
transfers it to the water running through it.
 48

• Test NO (6)
Reid vapor pressure

Standard code
ASTM D323&D5190

➢ Reid vapor pressure (RVP) is a common measure of the volatility of

gasoline. It is defined as the absolute vapor pressure exerted by a
liquid at 100 °F (37.8 °C) as determined by the test method ASTM-D-
323.
➢ The test method applies to vapor pressure of gasoline, volatile crude
oil, and other volatile petroleum products, except liquefied petroleum
gases.
➢ RVP stated in units of psi but would be more correct to state as psig as
ASTM-D-323 is measuring the gauge pressure of the sample in a non-
evacuated chamber.
➢ Pounds per square in gauge, or psig, is a measure of pressure,
specifically it is a gauge pressure.
➢ The proper testing of crude oil vapor pressure is critical for meeting
Hazardous Material Regulations and in determining the requirements
for safe transport.
➢ The risk of pressure build up inside a rail car and crude oil boil
increases significantly if the crude oil includes volatile components.
The term volatile components is used for crude oil components with a
high tendency to evaporate, such as dissolved hydrocarbon gases, air
or liquid components that begin to evaporate at a low temperature.
Scope of work
➢ To determine vapor pressure of gasoline, volatile crude oil and other
petroleum products.
➢ Method is suitable for testing samples with boiling point above 32F
that exert vapor pressure between (1-25PSI) @37.8C(100F)(at vapor to
liquid ratio 4:1).
➢ Values stated in SI units are to be regarded as the standard.
 49

Summary of Test Method

D323
➢ The liquid chamber of the vapor pressure apparatus is filled with the
chilled sample and connected to the vapor chamber that has been
heated to 37.8°C (100°F) in a bath.
➢ The assembled apparatus is immersed in a bath at 37.8°C (100°F) until
a constant pressure is observed. The reading, suitably corrected, is
reported as the Reid vapor pressure.
Significance and use
➢ Vapor pressure is an important physical property of volatile liquids.
➢ Vapor pressure of crude oils is of importance to the crude producer
and the refiner for general handling and initial refinery treatment.
➢ Vapor pressure is also used as an indirect measure of the evaporation
rate of volatile petroleum solvents.
➢ Apparatus
➢ Reid Vapor Pressure Apparatus, consisting of two Chambers:
➢ A vapor chamber (upper section).
➢ A liquid chamber (lower section).
➢ Constant temperature bath (100‫؛‬F).
Sampling precautions
➢ Perform the vapor pressure determination on the first test specimen
withdrawn from sample container (do not use remaining sample in
the container for a second vapor determination (for it obtain new one).
➢ Protect the sample from excessive temperature (storage in appropriate
ice bath or refrigerator).
➢ Do not test samples stored in leaky containers, if leaks are detected,
discard and obtain new sample.
 50

Sampling handling temperature

• Cool the sample container and contents in an ice bath or refrigerator
to between zero and 1 C prior to opening sample container.
• Discard the sample if the sample container is filled to less than 70%
volume of container capacity.
• If the container is more than 80% volume full, pour out enough
samples to bring container contents within 70 to 80% volume range.
• Reseal the container if necessary and return the sample container to
the cooling bath or refrigerator.
• PROCEDURE
• The sample is placed in a liquid chamber (cylinder) which is filled to
the tip then coupled to a vapor chamber as quickly as possible. (This
is done in such a way that vaporization losses are avoided).
• The sample is drained from the liquid to the vapor chamber and the
whole assembly is immersed in constant temperature bath (100ºF) for
5 minutes.
• The reading is observed after taping the pressure gage lightly.
• The apparatus is withdrawn from the bath and the procedure is
repeated as needed. The (uncorrected) RVP reading is recorded when
the difference between two readings is 0.05psi.
• Reid vapor pressure (RVP) is the pressure of the vapor above the fuel
when the fuel is at 100°F (38°C).
• Cold temperatures reduce the normal vaporization of gasoline;
therefore, winter blended gasoline is specially formulated to vaporize
at lower temperatures for proper starting and drivability at low
ambient temperatures.
• Reid vapor pressure. ... It is defined as the absolute vapor pressure
exerted by the vapor of the liquid and any dissolved gases/moisture at
37.8 °C (100 °F).

•
 51

R= Repeatability in the normal and correct operation of the test method, exceed
the following value only in one case in twenty:
2.48 kPa (0.36 psi)
Z= Reproducibility in the long run, exceed the following value only in one
case in twenty: 3.45 kPa (0.50 psi)
 52

• Test NO (7)
Oil in water determination

• To determine total amount of oil in ppm that are present in water due
to safety considerations.
• Main sources of UMB fields include UMB, KHP process API Water
and separator outlet.
• Oil in water can be determined by using either UV-VIS spectroscopy
or fluorescent spectroscopy.
• Oil in water determination by TURNER TD-500 depends on
fluorescent spectroscopy.
• What is fluorescence?
• Photon emission process.
• Fluorescence is the emission of light by a substance that has absorbed
light or other electromagnetic radiation.
• The emitted light has a longer wavelength, and therefore lower
energy, than the absorbed radiation.
• What is Fluorescence Spectroscopy?
• Fluorescence is the phenomenon where a molecule absorbs light
within its absorption band and then emits this light at longer
wavelengths within its emission band. This phenomenon can be used
to identify, quantify, and observe chemical activity, and it is a popular
method due to its high levels of sensitivity, simplicity, and specificity.

• Fluorescence spectroscopy is a spectroscopy method used to analyze

the fluorescence properties of a sample by determining the
concentration of an analyte in a sample. This technique is widely used
for measuring compounds in a solution, and it is a relatively easy
method to perform.
 53

• Fluorescence Spectroscopy Configuration

• In fluorescence spectroscopy, a light of a specific wavelength band is

passed through a solution, which emits the light towards a filter and
into a detector for measurement.

• The amount of light that is absorbed by the sample (excitation

spectrum) and the amount of light that is emitted by the sample
(emission spectrum) can be quantified.
• The concentration levels of the analyte compound within the solution
can be determined as these levels are directly proportional to the
emission spectrum.
• The most striking example of fluorescence occurs when the absorbed
radiation is in the ultraviolet region of the spectrum, and thus
invisible to the human eye.
• While the emitted light is in the visible region, which gives the
fluorescent substance a distinct color that can be seen only when
exposed to UV light.

• When light impinges upon matter, two things can happen. It can pass
through the matter with no absorption taking place, or it can be
absorbed either entirely or in part.
• Later, the energy is transferred to the molecule in the absorption
process. The quanta energy relationship can be expressed by the
equation = hν = hc/λ
• Where h, ν, c and λ are respectively, Planck’s constant, the frequency
of radiation, the velocity of light and the wavelength.
• The excess energy of an excited molecule is invariably lost, with an
ultimate return to the lowest vibrational level of the ground state.
Several mechanisms may be involved in this process.
 54

• From this point, the molecule may return to the ground state by
emission of photon (fluorescence), or by generation of heat (internal
conversion), or may change to an excited triplet state (intersystem
crossing) and then return to the ground state by emission of photon
(phosphorescence), or may undergo chemical change. The processes
that occur between the absorption and emission of light are usually
illustrated by the Jablonski diagram.

• Fluorescence is almost always the result of a transition between the

lowest energy level of the first excited state (S1) and some of the
ground state (S0).
• The lifetime of an excited singlet state, and therefore the decay time of
fluorescence is in the range 10-9 to 10-8 seconds.

• The fluorescence of a molecule is dependent upon the structure of the

molecule and upon the environment in which it is situated. Many
organic molecules are fluorescent.
 55

• In relation to organic compounds, fluorescence is restricted to

compounds possessing a fairly large conjugated system, in which
electrons less strongly bound than σ electrons, can be promoted to π*
antibonding orbitals by absorption of photon energy without
extensive disruption of bonding.

• Basic instrumentation:
• It contains a light source, two monochromators, a sample holder and a
detector.
• There are two monochromators, one for selection of the excitation
wavelength, another for analysis of the emitted light.
• The detector is at 90 degrees to the excitation beam.
• Upon excitation of the sample molecules, the fluorescence is emitted
in all directions and is detected by photocell at right angles to the
excitation light beam.
• The lamp source used is a xenon arc lamp that emits radiation in the
UV, visible and near-infrared regions.
• The exciting light then passes into the sample chamber which
contains fluorescence cuvette
• A special fluorescent cuvette with four translucent quartz or glass
sides is used.
• When the excited light impinges on the sample cell, molecules in the
solution are excited and some will emit light.
• Light emitted at right angles to the incoming beam is analyzed by the
emission monochromator.
• The wavelength analysis of emitted light is carried out by measuring
the intensity of fluorescence at preselected wavelength.
 56

• The analyzer monochromator directs emitted light of the preselected

wavelength to the detector.
• Detector to measure the intensity of the light.
• The output current from the detector is fed to some measuring device
that indicates the extent of fluorescence.
 57

• TD 500 operation principle:

• The TD-500D responds to the fluorescent aromatic compounds in the
target hydrocarbon.
• The instrument must be calibrated by measuring the intensity of
fluorescent light that is generated by a known concentration of
hydrocarbon. Once calibrated, the instrument converts the fluorescent
light intensity from an unknown sample into units of concentration.

• Every hydrocarbon will have a detection limit and a linearity limit.

The detection limit is the lowest concentration that the instrument
can detect.
• The linearity limit varies with each type of hydrocarbon. The
linear range is defined by the concentration span from the
detection limit to the linearity limit. As concentration increases
beyond the linearity limit, the slope of the line begins to reduce.
• At very high concentrations, the slope may become negative. For
most crude oils the linearity limit is well beyond 1000ppm.
• The TD-500D must be operating in the linear range to display
accurate results.
 58

Equipment
• Graduated bottles 125 ml.
• HCL solution.
• Suitable solvent chloroform (n-hexane).
• Fluorescent device (turner TD-500)
• Graduated cylinder 100 ml.
• Photocell tube.

Procedure

• Collect 100 ml from sample in clean glass bottle.

• Take 50 ml of tested sample.
• Add 2 or 3 drops of HCL (1:1).
• Add 50 ml of organic solvent (n-hexane).
• Shake vigorously for about 1 min.
• Let the dispersed oil to be extracted by n-hexane (wait
suitable time). Avoid formation of any air bubbles.
• Fill the cuvette cell by plastic dropper Pippet then insert to
the device then press read.
• Obtain & record your oil in water reading.
 59

For calibration follow the instructor manual procedure as

follows:
 60

Test NO (8)
Flash point test closed cup

Standard code
ASTM D93

Flash point by pensky-martens closed cup tester

• Scope of work:
• Determination of flash point of petroleum product in the temperature
range from 40 to 360C by a manual pensky martens closed cup
apparatus or an automated pensky martens closed cup apparatus.
• Two procedures are involved
• (Procedure A): for distillate fuel (diesel, kerosene, heating oil,
turbine fuels and new lubricating oil).
• Procedure B: residual fuel petroleum liquids with solids.
• Flash point determination as above 250°C can be performed; however,
the precisions have not been determined above this temperature.
• For residual fuels, precisions have not been determined for flash
points above 100°C.
• Terminology
• Flash point: the lowest corrected temperature at which application of
an ignition source causes the vapors of a specimen of the sample to
ignite under specified conditions of test.
• The test specimen is deemed to have flashed when a flame appears
and instantaneously propagates itself over the entire surface of the
test specimen.
• When the ignition source is a test flame, the application of the test
flame may cause a blue halo or an enlarged flame prior to the actual
flash point. This is not a flash point and shall be ignored.
 61

Summary of the test method

➢ Brass test cup of specified dimensions filled to the inside mark with
test specimen and fitted with a cover of specified dimensions is
heated and specimen stirred at specified rates.
➢ An ignition source is directed into the test cup at regular intervals
with simulation interruption of stirring until a flash is detected and
flash point is reported.

Significance and use

• One of number of properties, which should be considered for overall
flammability, hazards of material.
• Used in shipping and safety regulations to define flammable and
combustible material.
• Used to measure and describe the properties of materials, product
assemblies in response to heat and an ignition source under lab
conditions.

Apparatus

• Pensky martins closed cup apparatus (manual) consist of:

• Test cup
• Test cover, shutter
• Stirring device, heating source and ignition source device
• Air bath and top plate.
• Pensky martens closed cup apparatus (automated):
• An automated flash point instrument that is capable of performing
test in accordance with specified procedure.
• Temperature measuring device.
• Ignition source (natural gas flame, bottle gas flame and electric
igniters (hot wire) are acceptable.
 62

Reagent and materials

• For cleaning out the specimen from the test cup and drying the test
cup and cover.
• Toluene, acetone, and many solvents are flammable and a health
hazard. Dispose of solvents and waste material in accordance with
local regulations.
Sampling process
• Obtain sample at least 75ml of sample is required for each test.
• The sample container shall be at least 85 % full.
• Do not open cup unnecessarily to prevent loss of volatile materials or
possible introduction of moisture, or both.
• Avoid storage of samples at temperatures in excess of 35°C or 95°F.
• Samples for storage shall be capped tightly with inner seals.
• Do not make a transfer unless the sample temperature is at least the
equivalent of 18°C or 32°F below the expected flash point.
• Do not store samples in gas permeable containers; such volatile
materials may diffuse through the wall of enclosure.
• Samples of very viscous materials shall be heated in their containers
at the lowest temperature to liquefy any solids, not exceeding 28C or
50F below the expected flash point for 30mins (let it cool as no sample
shall be heated and transferred unless its temperatures is more than
18C or 32F BELOW its expected flash point before transfer.
• Samples containing dissolved or free water may be dehydrated with
calcium chloride or qualitative filter paper.
• Volatile vapors can escape during heating when the sample container
is not properly sealed.

Apparatus preparation
 63

➢ Support the manual or automated apparatus on a level steady surface

such as a table.
➢ Tests are to be performed in a draft free room or compartment tests
made in lab hood.
➢ Prepare the manual apparatus or the automated apparatus for
operation in accordance with the manufacturer’s instructions for
calibrating, checking and operating the equipment.

Apparatus verification
➢ Adjust the automated flash point detection system in accordance with
the manufacturer’s instructions.
➢ Verify that the temperature measuring device in accordance with
acceptable limits.
➢ Verify the performance of the manual apparatus or automated
apparatus at least once per year by determining the flash point of a
certified reference material (CRM).
➢ Once apparatus performance has been, verified flash point of
secondary working standard can be determined along with their
control limits.
➢ When flash point obtained is not within the limits stated, check in the
condition and operation of the apparatus to ensure apparatus
verification for test.

Procedure
• Fill the test cup with the test specimen to the filling mark inside of the
test cup.
• The thermometer of the test cup and test specimen shall be at least
18C OR 32F below the expected flash point, if too much test specimen
has been added to the test cup remove excess using a syringe or
similar device for withdrawal of fluid.
• Light the test flame or switch on the electric igniter and adjust
intensity in accordance with the manufacturer’s instruction.
 64

• Ignition source application( if the sample is expected to have a flash

point of 110C or 230F or below apply the ignition source when the
temperature of the test specimen is 23 (+or-5)C or 41(+OR-9)F below
the expected flash point.
• Discontinue the stirring of the tested sample and apply ignition
source by operating mechanism on the test cover which controls the
shutter so that ignition source is lowered into the vapor space of the
test cup in 0.5 sec, left in its lowered position for 1sec and quickly
raised to its upward position.
• If the tested sample is expected to have a flash point above, 110C or
230F apply the ignition source at each T increase of 2C or 5F beginning
at T of 23(+or-5C) or 41(+or-9) below expected flash point.
• When testing materials where the expected flash point temperature is
not known bring the material to be tested and the tester to a
temperature of (15C) or (60F).
• When the material is known to be very viscous at this temperature,
heat the specimen to starting temperature then apply ignition source.
• Record as the observed flash point the reading on the temperature-
measuring device at the time ignition source application cause a
distinct flash in the interior of the test cup.
• When ignition source is attest flame the application of the test flame
may cause blue halo this is not flash point and should be ignored.
• When flash point is detected on the first application, the test shall be
discontinued the result discarded and the test repeated with a fresh
test specimen (shall be 23 (+or-5) C or 41(+or-10) F below temperature
at which flash point was detected on the first application.
• When the apparatus has cooled down to a safe handling temperature
less than 55C (130F) remove the test cover, test cup, and clean the
apparatus as recommended by manufacturer.

Procedure (b)
 65

• Fill the cup with tested sample to the filling mark inside of the test
cup.
• Temperature of the test cup and tested sample shall be at least 18C or
32F below expected flash point.
• Remove too much specimen by using syringe or similar device for
liquid withdrawal.
• Place test cover on the test cup and place into the apparatus.
• Be sure that locating or looking device is properly connected.
• Insert the temperature-measuring device into its holder.
• Light test flame and adjust or switch electric igniter and adjust the
intensity in accordance with the manufacturer’s instructions.
• Turn stirring device apply the heat and record T.

Calculation

• Observe and record ambient barometric pressure at test time when p

differ from 760mm Hg correct as follows:
• Corrected F POINT= C+0.25(101.3-K)

=F+0.06(760-P)

=C+0.033(760-P)

WHERE

C= observed flash point @C

F= Observed flash point @F

P= ambient barometric pressure mmhg

K= ambient barometric pressure KPA.

Very important to revise this procedure

 66

About flash point

• The flash point is the lowest temperature at atmospheric pressure (760
mmHg, 101.3 kPa) at which application of a test flame will cause the
vapor of a sample to ignite under specified test conditions.
• Mechanism: Every liquid has a vapor pressure, which is a function of
that liquid's temperature. As the temperature increases, the vapor
pressure increases. As the vapor pressure increases, the concentration
of vapor of the flammable liquid in the air increases. Hence,
temperature determines the concentration of vapor of the flammable
liquid in the air.
• A certain concentration of vapor in the air is necessary to sustain
combustion, and that concentration is different for each flammable
liquid. The flash point of a flammable liquid is the lowest
temperature at which there will be enough flammable vapor to ignite
when an ignition source is applied.
• Fire Point: The temperature at which continuous flame is seen.
• Indication of fire risk.

• Test NO (8)
 67

Saybolt Universal Second(SSU)

➢ Viscosity: is the physical property of a fluid that offers internal

resistance to flow.
➢ There are various instruments for measuring viscosity called
viscometers.
➢ The most widely used viscometers in the United States are kinematic
and the Saybolt universal.
➢ The Engler viscometer is used in continental Europe and the redwood
viscometers are used in England.
➢ Because of these differences, interchange of technical information
makes it necessary to provide tables for converting viscosities from
one type to another.
The Saybolt universal second (SUS or SSU)
➢ It is a measure of kinematic viscosity used in classical mechanics.
➢ It is the time that 60 cm3 of oil takes to flow through a calibrated tube
at a controlled temperature, 38°C.
➢ The SUS is used for oils with low to medium viscosity such as
machine oils.
➢ Saybolt Furol seconds is measured with a controlled temperature of 50
deg C.
➢ The tube diameter in the two scales is such that the Furol viscosity is
one-tenth of the universal viscosity.

Apparatus
 68

• The saybolt viscometer consists essentially of cylindrically brass cup

in the bottom of which an orifice of specified dimensions
(surrounding the brass cup is a constant temperature bath).

Procedure
• Fill in the sample into its specified place.
• Measure sample temperature (T) by using thermometer.
• Adjust bath t to 40C.
• Put; adjust viscometer into its specified place.
• Loose cork, let oil flow, and calculates time.
• Express viscosity in sus unit.(When the sample in the cup reaches test
temperature, the time required for 60 ml of the liquid to run through
the orifice is measured. A calibrated standard flask collects the liquid
sample.)
Reporting
• The unit of measurement is time in seconds it is reported as saybolt
universal second, for example it is reported as 350 SUS @100F.

TEMPERATURE EFFECT ON VISCOSITY

 69

(So we keep T constant)

• The saybolt Furol viscometer is the same in principle as the universal

viscometer with the exception that it is designed with a larger orifice
to accommodate fluids that are more viscous.
• The unit of measure is also time in seconds required for 60 ml of fluid
to flow through the orifice at a given temperature.
• Stokes (symbol: St) this is the cgs unit, equivalent to square
centimeter per second. One stokes is equal to the viscosity in poise
divided by the density of the fluid in g cm–3. It is most usually
encountered as the centistokes (CST) (= 0.01 stokes).
• Apparatus figuration
 ‫‪70‬‬

‫بعض التعليمات الواجب اخذها في االعتبار اثناء التجربة‬

‫‪-1‬التأكد من سالمة الجهاز مع ظبط زاوية ميل الجهاز وبالتالي البد من ظبط الجهاز أوال‪.‬‬

‫‪-2‬ظبط درجة الحرارة عند ‪ 40‬درجة سلزيوس مع تشغيل وحدات الجهاز‬

‫‪-3‬التأكد من منسوب ومستوي الزيت داخل الجهاز‪.‬‬

‫‪-4‬شروط البد من توافرها في الزيت المستخدم‪.‬‬

‫يغلي عند مدي من درجات الحرارة أكبر من الزيت المراد قياسه‬

‫ال يحدث له تكسير حراري أي غير قابل للتفكك لذلك أحيانا يتم إضافة كيماويات اخري للزيت المستخدم‪.‬‬

‫ال تتغير خواص الكيميائية مع ضرورة تغير الزيت عند تغير خواصه او أصبح معتم اللون او تغير الوسط‪.‬‬

‫للحفاظ على درجة الحرارة ممثلة وثابتة لدقة النتائج)‪.‬‬

‫)‪Mixer‬‬
 71

Test NO (9)
WATER CONTENT IN PET PRODUCTS

KARL FISCHER
• Standard test method for determination of water in
petroleum product, lubricating oil, and additives by
coulometric Karl Fischer titration (D6304).
SCOPE
• This method covers direct determination of water in the range of 10 to
25000mg/KG entrained water in petroleum products and
hydrocarbons using instrumentation (water determination of water in
additives, lube oil, base oil).
Summary of test method
• Sample is injected into the titration vessel of coulometric Karl Fischer
apparatus in which Iodine for the Karl Fischer. Reaction is generated
at the anode when all of water has been titrated, excess iodine is
detected by an electrometric end point detector and titration is
terminated.
• Note one mole of iodine reacts with one mole of water
I2+H2O===== OI- +2H+ +I-

Quantity of water is proportional to the total integrated current

according faraday’s law

‫كتلة المادة المتفاعلة في قطب كهربائي أثناء التحليل الكهربي تتناسب طرديا مع كمية الكهرباء المنقولة‬
‫في هذا القطب‬

‫لكمية معينة من الكهرباء فان كتلة عنصر ما متفاعل عند قطب كهربائي تتناسب طرديا مع الوزن المكافئ‬
‫لهذا العنصر‬

• Sample injection can be done by either mas or volume (special

procedure for viscous samples)
 72

• Significance & use

• Knowledge of water content is very important in manufacturing, sale
or transfer of such petroleum products to help in predicting their
quality and performance characteristics.
• Interference
• In petroleum products, the most common interference is mercaptans
and sulfides at levels of less than 500mg/kg the sulfur interfere as
sulfides.
• For water concentrations >0.02 mass interference is not significant.
• Apparatus
• Coulometric Karl Fischer apparatus consists of:
• Titration cell.
• Platinum electrodes.
• Magnetic stirrer.
• Control unit available in the market (instructions are provided by the
manufacturer.
• Syringe for adding samples to titration vessel.
• Karl Fischer reagent commercially available.
• Anode solution (mix parts of commercial Karl Fischer).
**Sampling**

➢ Sampling here is defined, as all steps required obtaining an

aliquot representative of all contents of any pipe, tank or
other system and place into container for analysis.
Expected water conc Sample size in g or Mg water titrated
ml
10-100 (mg/kg) 3 30-300
10-500(mg/kg) 2 200-1000
0.02 to 0.1% 1 200-1000
0.1 to 0.5 % 0.5 500-2500
0.5 to 2.5% 0.25 1250-6250
 73

Apparatus & preparation

• Follow manufacturer directions for preparation and

operation for titration apparatus.
• Seal all joints and connections to vessel and prevent
atmospheric moisture from entering the apparatus.
• Add Karl Fischer anode solution to the anode (outer
compartment) add the solution to level recommended by
manufacturer.
• Add Karl Fischer cathode solution to the cathode inner
compartment (add solution to level 2 to 3 mm below the
level of solution in the anode compartment.
• Turn on the apparatus and start the magnetic stirrer for a
smooth stirring action , allow residual moisture in the
titration vessel to be titrated until end point is reached In
general standardization is not necessary since the water
titrated is a direct function of the coulombs of electricity
consumed.
Procedure (by mass)

• Add petroleum product test specimen to the titration

vessel using the following method:
• Start with clean, dry syringe of suitable capacity.
• Withdraw portion of the sample, clean the needle with a
paper tissue and weigh the syringe and contents to the
nearest0.1mg.
• Insert the needle through inlet port septum start the
titration.
 74

• Withdraw the syringe, wipe clean with a paper tissue and

reweigh the syringe to the nearest 0.1mg.
• After the end is reached record micrograms of, water
titrated.
Calculation

• Water mass%= W1/10000*W2

• Where W1 mass of sample titrated mMg
• W2 mass of sample used in g