ASTM D4007-02(2006)
(Test Method)Standard Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure)
Standard Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure)
SIGNIFICANCE AND USE
The water and sediment content of crude oil is significant because it can cause corrosion of equipment and problems in processing. A determination of water and sediment content is required to measure accurately net volumes of actual oil in sales, taxation, exchanges, and custody transfers.
SCOPE
1.1 This test method describes the laboratory determination of water and sediment in crude oils by means of the centrifuge procedure. This centrifuge method for determining water and sediment in crude oils is not entirely satisfactory. The amount of water detected is almost always lower than the actual water content. When a highly accurate value is required, the revised procedures for water by distillation, Test Method D 4006 (API MPMS Chapter 10.2) (), and sediment by extraction, Test Method D 473 (API MPMS Chapter 10.1), shall be used. Note 1Test Method D 4006 (API MPMS Chapter 10.2) has been determined to be the preferred and most accurate method for the determination of water.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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. For specific precautionary statements, see 6.1.
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An American National Standard
Designation:D4007–02 (Reapproved 2006)
Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 10.3
Standard Test Method for
Water and Sediment in Crude Oil by the Centrifuge Method
(Laboratory Procedure)
This standard is issued under the fixed designation D4007; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D473 Test Method for Sediment in Crude Oils and Fuel
Oils by the Extraction Method (API MPMS Chapter 10.1)
1.1 This test method describes the laboratory determination
D665 Test Method for Rust-Preventing Characteristics of
of water and sediment in crude oils by means of the centrifuge
Inhibited Mineral Oil in the Presence of Water
procedure. This centrifuge method for determining water and
D1796 TestMethodforWaterandSedimentinFuelOilsby
sediment in crude oils is not entirely satisfactory. The amount
the Centrifuge Method (Laboratory Procedure) (API
of water detected is almost always lower than the actual water
MPMS Chapter 10.6)
content. When a highly accurate value is required, the revised
D4006 Test Method for Water in Crude Oil by Distillation
procedures for water by distillation,Test Method D4006 (API
(API MPMS Chapter 10.2)
MPMS Chapter 10.2) (Note 1), and sediment by extraction,
D4057 Practice for Manual Sampling of Petroleum and
Test Method D473 (API MPMS Chapter 10.1), shall be used.
Petroleum Products (API MPMS Chapter 8.1)
NOTE 1—Test Method D4006 (API MPMS Chapter 10.2) has been
D4177 Practice for Automatic Sampling of Petroleum and
determined to be the preferred and most accurate method for the
Petroleum Products (API MPMS Chapter 8.2)
determination of water.
D 5854 Practice for Mixing and Handling of Liquid
1.2 The values stated in SI units are to be regarded as the
Samples of Petroleum and Petroleum Products (API
standard. The values given in parentheses are for information
MPMS Chapter 8.3)
only.
E969 Specification for Glass Volumetric (Transfer) Pipets
1.3 This standard does not purport to address all of the
2.2 API Standards:
safety concerns, if any, associated with its use. It is the
MPMS Chapter 8.1 Manual Sampling of Petroleum and
responsibility of the user of this standard to establish appro-
Petroleum Products (ASTM Practice D4057)
priate safety and health practices and determine the applica-
MPMS Chapter 8.2 Automatic Sampling of Petroleum and
bility of regulatory limitations prior to use. For specific
Petroleum Products (ASTM Practice D4177)
precautionary statements, see 6.1.
MPMSChapter8.3 MixingandHandlingofLiquidSamples
of Petroleum and Petroleum Products (ASTM Practice
2. Referenced Documents
D5854)
2.1 ASTM Standards:
MPMS Chapter 10.1 Determination of Sediment in Crude
D95 Test Method for Water in Petroleum Products and
Oils and Fuel Oils by the Extraction Method (ASTMTest
Bituminous Materials by Distillation (API MPMS Chapter
Method D473)
10.5)
MPMS Chapter 10.2 Determination of Water in Crude Oil
by Distillation (ASTM Test Method D4006)
MPMS Chapter 10.4 Determination of Sediment and Water
This test method is under the jurisdiction of ASTM Committee D02 on
in Crude Oil by the Centrifuge Method (Field Procedure)
Petroleum Products and Lubricants and theAPI Committee on Petroleum Measure-
MPMS Chapter 10.5 Determination of Water in Petroleum
ment,andisthedirectresponsibilityofSubcommitteeD02.02.0B/COMQ,thejoint
Products and Bituminous Materials by Distillation
ASTM-API Committee on Sampling, Sediment, Water.
Current edition approved Nov. 1, 2006. Published December 2006. Originally
(ASTM Test MethodD95)
approved in 1981. Last previous edition approved in 2002 as D4007–02.
MPMS Chapter 10.6 Determination of Water and Sediment
This test method has been approved by the sponsoring committees and accepted
in Fuel Oils by the Centrifuge Method (Laboratory Pro-
by the Cooperating Societies in accordance with established procedures. This
method was issued as a joint ASTM-API-IP standard in 1981. cedures) (ASTM Test Method D1796)
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American Petroleum Institute (API), 1220 L. St., NW, Wash-
the ASTM website. ington, DC 20005-4070, http://api-ec.api.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4007–02 (2006)
2.3 IP Standard:
d = diameter of swing measured between tips of opposite
Methods Book, Appendix B Specification for Methylben-
tubes when in rotating position, in.
zenes (Toluenes)
5.1.6 Calculate the relative centrifugal force from a mea-
2.4 ISO Standard:
sured speed (r/min) as follows:
ISO 5272:1979 Toluene for Industrial Use—Specifications
r/min
rcf 5 d (3)
S D
3. Summary of Test Method
where:
3.1 Equal volumes of crude oil and water-saturated toluene
d = diameter of swing measured between tips of opposite
are placed into a cone-shaped centrifuge tube. After centrifu-
tubes when in rotating position, mm, or
gation, the volume of the higher density water and sediment
layer at the bottom of the tube is read. r/min
rcf 5 d (4)
S D
4. Significance and Use
where:
4.1 The water and sediment content of crude oil is signifi-
d = diameter of swing measured between tips of opposite
cantbecauseitcancausecorrosionofequipmentandproblems
tubes when in rotating position, in.
inprocessing.Adeterminationofwaterandsedimentcontentis
5.2 Centrifuge Tubes—Each centrifuge tube shall be a
required to measure accurately net volumes of actual oil in
203-mm (8-in.) cone-shaped tube, conforming to dimensions
sales, taxation, exchanges, and custody transfers.
given in Fig. 1 and made of thoroughly annealed glass. The
graduations, numbered as shown in Fig. 1, shall be clear and
5. Apparatus
distinct,andthemouthshallbeconstrictedinshapeforclosure
5.1 Centrifuge:
withacork.Scaleerrortolerancesandthesmallestgraduations
5.1.1 A centrifuge capable of spinning two or more filled
between various calibration marks are given in Table 1 and
cone-shaped, 203-mm (8-in.) centrifuge tubes at a speed that
apply to calibrations made with air-free water at 20°C (68°F),
can be controlled to give a relative centrifugal force (rcf) of a
whenreadingthebottomoftheshadedmeniscus.Theaccuracy
minimumof600atthetipofthetubesshallbeused(see5.1.6).
of the graduations on the centrifuge tube shall be volumetri-
5.1.2 Therevolvinghead,trunnionrings,andtrunnioncups,
cally verified, before use of the tube. The verification shall
including the cushions, shall be soundly constructed to with-
include calibration at each mark up to the 0.25 mL mark (as
stand the maximum centrifugal force capable of being deliv-
eredbythepowersource.Thetrunnioncupsandcushionsshall
firmly support the tubes when the centrifuge is in motion. The
centrifuge shall be enclosed by a metal shield or case strong
enough to eliminate danger if any breakage occurs.
5.1.3 The centrifuge shall be heated and controlled thermo-
statically to avoid unsafe conditions. It shall be capable of
maintaining the sample temperature during the entire run at 60
6 3°C (140 6 5°F). The thermostatic control shall be capable
of maintaining the temperature within these limits and operate
safely if there is a flammable atmosphere.
5.1.4 Electricpoweredandheatedcentrifugesmustmeetall
safety requirements for use in hazardous areas.
5.1.5 Calculate the necessary minimum speed of the rotat-
ing head in revolutions per minute (r/min) as follows:
r/min 51335 rcf/d (1)
=
where:
rcf = relative centrifugal force and
d = diameter of swing measured between tips of opposite
tubes when in rotating position, mm, or
r/min 5265 rcf/d (2)
=
where:
rcf = relative centrifugal force and
Available from the Institute of Petroleum, 61 New Cavendish Street, London,
W1G 7AR, U.K.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. FIG. 1 Eight-Inch (203-mm) Centrifuge Tube
D4007–02 (2006)
TABLE 1 Centrifuge Tube Calibration Tolerances
7. Sampling
for 203-mm (8-in.) Tube
7.1 Sampling is defined as all steps required to obtain an
Range, mL Subdivision, mL Volume Tolerance, mL
aliquotofthecontentsofanypipe,tank,orothersystemandto
0to0.1 0.05 60.02
place the sample into the laboratory test container.
Above 0.1 to 0.3 0.05 60.03
Above 0.3 to 0.5 0.05 60.05
7.2 Only representative samples obtained as specified in
Above 0.5 to 1.0 0.10 60.05
Practices D4057 (API MPMS Chapter 8.1) and Practice
Above 1.0 to 2.0 0.10 60.10
D4177 (API MPMS Chapter 8.2) shall be used for this test
Above 2.0 to 3.0 0.20 60.10
Above 3.0 to 5.0 0.5 60.20
method.
Above 5.0 to 10 1.0 60.50
7.3 Sample Mixing—is typically required to obtain a test
Above 10 to 25 5.0 61.00
Above 25 to 100 25.0 61.00 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 petro-
leum containing water or sediments, or both, may result in the
showninFig.2),andatthe0.5,1.0,1.5,2.0,50.0,and100mL lossoflightcomponents.Additionalinformationonthemixing
marks.Thetubeshallnotbeusedifthescaleerroratanymark
andhandlingofliquidsamplescanbefoundinPracticeD5854
exceeds the applicable tolerance from Table 1. (API MPMS Chapter 8.3).
5.3 Bath—The bath shall be either a solid metal block bath
8. Procedure
oraliquidbathofsufficientdepthforimmersingthecentrifuge
tube in the vertical position to the 100-mL mark. Means shall
8.1 Fill each of two centrifuge tubes (5.2) to the 50-mL
be provided for maintaining the temperature at 60 6 3°C (140
mark with sample directly from the sample container. Using a
65°F).Forsomecrudeoils,temperaturesof71 63°C(160 6
pipet or other suitable volume transfer device (see 5.4), add 50
5°F) may be required to melt wax crystals in crude oils. For
6 0.05 mLof toluene, which has been water saturated at 60°C
these crude oils, the test temperature shall be maintained high
(140°F) or 71°C (160°F) (see 5.3). Read the top of the
enough to ensure the absence of wax crystals.
meniscus at both the 50 and 100-mL marks. Add 0.2 mL of
5.4 50 mL Pipet, ClassA, or equivalent volume dispensing demulsifiersolution(6.2)toeachtube,usinga0.2-mLpipetor
other suitable volume transfer device, such as an automatic
device, capable of delivering a volume of 50 6 0.05 mL (see
pipettor. Stopper the tube tightly and invert the tubes ten times
Specification E969) for use in the test.
to ensure that the oil and solvent are uniformly mixed.
6. Solvent 8.2 In the case where the crude oil is very viscous and
mixingofthesolventwiththeoilwouldbedifficult,thesolvent
6.1 Toluene—conforming to the IP Specification for Meth-
may be added to the centrifuge tube first to facilitate mixing.
ylbenzenes (Toluenes) or to ISO 5272. (Warning—
Take care to not fill the centrifuge tube past the 100-mL mark
Flammable. Keep away from heat, sparks, and open flame.
with the sample.
Vapor harmful. Toluene is toxic. Particular care must be taken
8.3 Loosen the stoppers slightly and immerse the tubes to
to avoid breathing the vapor and to protect the eyes. Keep
the 100-mLmark for at least 15 min in the bath maintained at
container closed. Use with adequate ventilation. Avoid pro-
60 63°C(140 65°F)(see5.3).Securethestoppersandagain
longed or repeated contact with the skin.)
invert the tubes ten times to ensure uniform mixing of oil and
6.1.1 Typical characteristics for this reagent are:
solvent. (Warning—The vapor pressure at 60°C (140°F) is
Molecular weight C H CH 92.14
6 5 3
approximately double that at 40°C (104°F).)
Color (APHA) 10
A
Boiling range (initial to dry point) 2.0°C (3.6°F) 8.4 Placethetubesinthetrunnioncupsonoppositesidesof
Residue after evaporation 0.001 %
the centrifuge to establish a balanced condition. (If the tubes
Substances darkened by H SO passes ACS test
2 4
cannot be counter-balanced by eye, place them, in their
Sulfur compounds (as S) 0.003 %
_______ trunnion cups, on either side of a balance and equalize their
A
Recorded boiling point 110.6°C
masses by the addition of water to the trunnion cups.) Re-
tighten the corks and spin for 10 min at a minimum relative
centrifugal force of 600 calculated from the equation given in
6.1.2 Thesolventshallbewater-saturatedat60 63°C(140
6 5°F) (see 5.3) but shall be free of suspended water. See 5.1.6.
Annex A1 for the solvent-water saturation procedure.
8.5 Immediatelyafterthecentrifugecomestorestfollowing
6.2 Demulsifier—A demulsifier should be used to promote the spin, read and record the combined volume of water and
sediment at the bottom of each tube, to the nearest 0.05 mL
the separation of water from the sample and to prevent its
from0.1to1-mLgraduations,andtothenearest0.1-mLabove
clinging to the walls of the centrifuge tube.The recommended
1-mL graduations. Below 0.1 mL, estimate to the nearest
stock solution is 25% demulsifier to 75% toluene. For some
0.025mL(refertoFig.2).Returnthetubeswithoutagitationto
crude oils a different ratio of demulsifier to toluene may be
the centrifuge and spin for another 10 min at the same rate.
required. Demulsifiers used in the concentration and quantity
recommended will not add to the water and sediment volume 8.6 Repeat this operation until the combined volume of
determined.The solution must be stored in a dark bottle that is
water and sediment remains constant for two consecutive
tightly closed. readings.Ingeneral,notmorethantwospinningsarerequired.
D4007–02 (2006)
FIG. 2 Procedure for Reading Water and Sediment When Using an ASTM 100-mm Cone-Shaped Centrifuge Tube
D4007–02 (2006)
TABLE 2 Expression of Results, mL
Total Percent Water and
Tube 1 Tube 2
Sediment, % (V/V)
No visible water and No visible water and 0.00
sediment sediment
No visible water and 0.025 0.025
sediment
0.025 0.025 0.05
0.025 0.05 0.075
0.05 0.05 0.10
0.05 0.075 0.125
0.075 0.075 0.15
0.075 0.10 0.175
0.10 0.10 0.20
0.10 0.15 0.25
10.1.1 Repeatability—The difference between two test re-
sults, 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
thetestmethod,exceedthefollowingvalueinonlyonecasein
FIG. 3 Basic Sedimen
...
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