ASTM D5002-99(2005)
(Test Method)Standard Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer
Standard Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer
SIGNIFICANCE AND USE
Density is a fundamental physical property that can be used in conjunction with other properties to characterize the quality of crude oils.
The density or relative density of crude oils is used for the conversion of measured volumes to volumes at the standard temperatures of 15°C or 60°F and for the conversion of crude mass measurements into volume units.
The application of the density result obtained from this test method, for fiscal or custody transfer accounting calculations, can require measurements of the water and sediment contents obtained on similar specimens of the crude oil parcel.
SCOPE
1.1 This test method covers the determination of the density or relative density of crude oils that can be handled in a normal fashion as liquids at test temperatures between 15 and 35C. This test method applies to crude oils with high vapor pressures provided appropriate precautions are taken to prevent vapor loss during transfer of the sample to the density analyzer.
1.2 This test method was evaluated in round robin testing using crude oils in the 0.75 to 0.95 g/mL range. Lighter crude oil can require special handling to prevent vapor losses. Heavier crudes can require measurements at higher temperatures to eliminate air bubbles in the sample.
1.3 The values stated in SI units are to be regarded as the standard. The accepted units of measurement of density are grams per millilitre and kilograms per cubic metre.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific warning statements are given in 7.4, 7.5, and 7.6.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5002–99 (Reapproved 2005)
Standard Test Method for
Density and Relative Density of Crude Oils by Digital
Density Analyzer
This standard is issued under the fixed designation D5002; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D4052 Test Method for Density and Relative Density of
Liquids by Digital Density Meter
1.1 This test method covers the determination of the density
D4057 Practice for Manual Sampling of Petroleum and
or relative density of crude oils that can be handled in a normal
Petroleum Products
fashion as liquids at test temperatures between 15 and 35°C.
D4177 Practice for Automatic Sampling of Petroleum and
Thistestmethodappliestocrudeoilswithhighvaporpressures
Petroleum Products
provided appropriate precautions are taken to prevent vapor
D4377 Test Method for Water in Crude Oils by Potentio-
loss during transfer of the sample to the density analyzer.
metric Karl Fischer Titration
1.2 This test method was evaluated in round robin testing
using crude oils in the 0.75 to 0.95 g/mL range. Lighter crude
3. Terminology
oil can require special handling to prevent vapor losses.
3.1 Definitions:
Heavier crudes can require measurements at higher tempera-
3.1.1 density—mass per unit volume at a specified tempera-
tures to eliminate air bubbles in the sample.
ture.
1.3 The values stated in SI units are to be regarded as the
3.1.2 relative density—the ratio of the density of a material
standard. The accepted units of measurement of density are
at a stated temperature to the density of water at a stated
grams per millilitre and kilograms per cubic metre.
temperature.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 Approximately 0.7 mLof crude oil sample is introduced
priate safety and health practices and determine the applica-
into an oscillating sample tube and the change in oscillating
bility of regulatory limitations prior to use. Specific warning
frequency caused by the change in the mass of the tube is used
statements are given in 7.4, 7.5, and 7.6.
in conjunction with calibration data to determine the density of
the sample.
2. Referenced Documents
2.1 ASTM Standards:
5. Significance and Use
D941 Test Method for Density and Relative Density (Spe-
5.1 Density is a fundamental physical property that can be
cific Gravity) of Liquids by Lipkin Bicapillary Pycnom-
3 used in conjunction with other properties to characterize the
eter
quality of crude oils.
D1193 Specification for Reagent Water
5.2 The density or relative density of crude oils is used for
D1217 Test Method for Density and Relative Density (Spe-
theconversionofmeasuredvolumestovolumesatthestandard
cific Gravity) of Liquids by Bingham Pycnometer
temperatures of 15°C or 60°F and for the conversion of crude
D1250 GuideforUseofthePetroleumMeasurementTables
mass measurements into volume units.
5.3 The application of the density result obtained from this
test method, for fiscal or custody transfer accounting calcula-
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
tions, can require measurements of the water and sediment
D02.04 on Hydrocarbon Analysis.
contents obtained on similar specimens of the crude oil parcel.
Current edition approved Nov. 1, 2005. Published November 2005. Originally
approved in 1989. Last previous edition approved in 1999 as D5002 – 99. DOI:
6. Apparatus
10.1520/D5002-99R05.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.1 Digital Density Analyzer—Adigital analyzer consisting
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
of a U-shaped, oscillating sample tube and a system for
Standards volume information, refer to the standard’s Document Summary page on
electronic excitation, frequency counting, and display. The
the ASTM website.
Withdrawn. analyzer must accommodate the accurate measurement of the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5002–99 (2005)
sample temperature during measurement or must control the place the sample into the laboratory test container. The
sampletemperatureasdescribedin6.2and6.5.Theinstrument laboratory test container and sample volume shall be of
shall be capable of meeting the precision requirements de- sufficient dimensions to allow mixing as described in 8.3.1.
scribed in Test Method D4052. Mixing is required to obtain a homogeneous sample for
6.2 Circulating Constant-Temperature Bath, capable of analysis.
maintaining the temperature of the circulating liquid constant 8.2 Laboratory Sample—Use only representative samples
to 60.05°C in the desired range. Temperature control can be obtained as specified in Practices D4057 or D4177 for this test
maintained as part of the density analyzer instrument package. method.
6.3 Syringes, at least 2 mL in volume with a tip or an 8.3 Test Specimen—The aliquot of sample obtained from
adapter tip that will fit the inlet of the density analyzer. the laboratory sample and delivered to the density analyzer
6.4 Flow-Through or Pressure Adapter, for use as an sample tube. The test specimen is obtained as follows:
alternative means of introducing the sample into the density 8.3.1 Mix the sample of crude oil to homogenize any
meter. sediment and water present. The mixing may be accomplished
6.5 Thermometer, calibrated and graduated to 0.1°C, and a as described in Practice D4177 or Test Method D4377. Mixing
thermometer holder that can be attached to the instrument for at room temperature in an open container can result in the loss
setting and observing the test temperature. In calibrating the of light ends, so mixing in closed, pressurized containers or at
thermometer, the ice point and bore corrections should be sub-ambient temperatures is recommended.
estimated to the nearest 0.05°C. Precise setting and control of 8.3.2 Draw the test specimen from a properly mixed labo-
the test temperature in the sample tube is extremely important. ratorysampleusinganappropriatesyringe.Alternatively,ifthe
Anerrorof0.1°Ccanresultinachangeindensityofoneinthe proper density analyzer attachments and connecting tubes are
fourth significant figure. used then the test specimen can be delivered directly to the
analyzer’s sample tube from the mixing container.
7. Reagents and Materials
9. Preparation of Apparatus
7.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated it is intended that 9.1 Set up the density analyzer and constant temperature
all reagents shall conform to the specifications of the Commit- bath following the manufacturer’s instructions.Adjust the bath
tee onAnalytical Reagents of theAmerican Chemical Society, or internal temperature control so that the desired test tempera-
where such specifications are available. Other grades may be ture is established and maintained in the sample compartment
used, provided it is first ascertained that the reagent is of of the analyzer. Calibrate the instrument at the same tempera-
sufficiently high purity to permit its use without lessening the ture at which the density of the sample is to be measured.
accuracy of the determination.
10. Calibration of Apparatus
7.2 Purity of Water—Unless otherwise indicated, references
10.1 Calibrate the instrument when first setting up and
to water shall be understood to mean reagent water as defined
whenever the test temperature is changed. Thereafter, conduct
by Type II of Specification D1193.
calibration checks at least weekly during routine operation or
7.3 Water, redistilled, freshly boiled and cooled reagent
more frequently as may be dictated by the nature of the crude
water for use as a primary calibration standard.
oils being measured (see 10.3).
7.4 Acetone, for flushing and drying the sample tube.
10.2 Initial calibration, or calibration after a change in test
(Warning—Extremely flammable.)
temperature, necessitates calculation of the values of the
7.5 Petroleum Naphtha, for flushing viscous petroleum
Constants A and B from the periods of oscillation, (T),
samples from the sample tube. (Warning—Extremely flam-
observed when the sample cell contains certified reference
mable.)
liquids such as air and double-distilled boiled water. Other
NOTE 1—Suitable solvent naphthas are marketed under various desig-
calibrating materials such as n-nonane, n-tridecane, cyclohex-
nations such as “petroleum ether,” “ligroine,” or “precipitation naphtha.”
ane, and n-hexadecane (for high temperature applications) can
7.6 n-Nonane, n-tridecane or cyclohexane, 99 % purity or
also be used as appropriate.
better, or similar pure material for which the density is known
10.2.1 While monitoring the oscillator period, T, flush the
precisely from literature references or by direct determination
sample tube with petroleum naphtha, followed with an acetone
in accordance with Test Method D941 or D1217.(Warning—
flush and dry with dry air. Continue drying until the display
Extremely flammable.)
exhibits a steady reading. In cases where saline components
can be deposited in the cell, flush with distilled water followed
8. Sampling, Test Specimens, and Test Units
by acetone and dry air. Contaminated or humid air can affect
8.1 Sampling is defined as all the steps required to obtain an
the calibration. When these conditions exist in the laboratory,
aliquot of the contents of any pipe, tank or other system, and to
pass the air used for calibration through a suitable purification
and drying train. In addition, the inlet and outlet ports for the
U-tube must be plugged during measurement of the calibration
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
air to prevent ingress of moist air.
listed by the American Chemical Society, see Analar Standards for Laboratory
10.2.2 Allow the dry air in the U-tube to come to thermal
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
equilibrium with the test temperature and record the T-value
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. for air.
D5002–99 (2005)
10.2.3 Introduce about 0.7 mL of freshly boiled and cooled 10.2.11 To calibrate the instrument to determine relative
double-distilled water into the sample tube from the bottom density,thatis,thedensityofthesampleatagiventemperature
opening using a suitable syringe. The water must be free of referred to the density of water at the same temperature, follow
even the smallest air or gas bubbles. The sample tube shall be 10.2.1-10.2.9, but substitute 1.000 for d in performing the
w
completely full. Allow the water to reach thermal equilibrium calculations described in 10.2.8.
at the test temperature and record the T-value for water and the 10.3 Since some crude oils can be difficult to remove from
test temperature. the sample tube, frequent calibration checks are recommended.
10.2.4 Alternatively introduce one of the hydrocarbon cali- These checks and any subsequent adjustments to Constants A
bration standards and measure the T-value as in 10.2.3. and B can be made if required, without repeating the calcula-
10.2.5 Calculate the density of air at the temperature of test tion procedure.
using the following equation:
NOTE 2—The need for a change in calibration is generally attributable
d 5 0.001293[273/T]@P/760] g/mL (1) to deposits in the sample tube that are not removed by the routine flushing
a
procedure.Although this condition can be compensated for by adjustingA
where:
and B, as described below, it is good practice to clean the tube with warm
T = temperature, K, and chromic acid solution (Warning—Causes severe burns. A recognized
P = barometric pressure, torr. carcinogen.) whenever a major adjustment is required. Chromic acid
solution is the most effective cleaning agent; however, surfactant-type
10.2.6 Determine the density of water at the temperature of
cleaning fluids have also been used successfully.
test by reference to Table 1.
10.2.7 Alternatively record the density at the test tempera- 10.3.1 Flush and dry the sample tube as described in 10.2.1
ture for the hydrocarbon calibrant used in 10.2.4 as obtained and allow the display to reach a steady reading. If the display
from an appropriate reference source or from direct determi- does not exhibit the correct T-value or density for air at the
nation (see 7.6). temperature of test, repeat the cleaning procedure or adjust the
10.2.8 Usingtheobserved T-valuesandthereferencevalues value of Constant B commencing with the last decimal place
for water and air, calculate the values of the ConstantsAand B
until the correct density is displayed.
using the following equations: 10.3.2 If adjustment to Constant B was necessary in 10.3.1
then continue the recalibration by introducing freshly boiled
2 2
A 5 [T 2 T #/[d 2 d # (2)
w a w a
and cooled double-distilled water into the sample tube as
B 5 T 2 ~A 3 d ! (3)
a a described in 10.2.3 and allowing the display to reach a steady
reading. If the instrument has been calibrated to display the
where:
density, adjust the reading to the correct value for water at the
T = observed period of oscillation for cell containing
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test temperature (see Table 1) by changing the value of
water,
Constant A, commencing with the last decimal place. If the
T = observed period of oscillation for cell containing air,
a
instrument has been calibrated to display the relative density,
d = density of water at test temperature, and
w
adjust the reading to the value 1.0000.
d = density of air at test temperature.
a
Alternatively, use the T and d values for the other reference
NOTE 3—In applying this periodic calibration procedure, it has been
liquid if one is used.
found that more than one value each for A and B, differing in the fourth
10.2.9 If the instrument is equipped to calculate density decimal place, will yield the correct reading for the density of air and
water. The setting chosen would then be dependent upon whether it was
from the ConstantsAand B and the observed T-value from the
approached from a higher or lower value. The setting selected by this
sample, then enter the constants in the instrument memory in
method could have the effec
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