ASTM D6749-02(2012)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6749 − 02 (Reapproved 2012)
Standard Test Method for
Pour Point of Petroleum Products (Automatic Air Pressure
Method)
This standard is issued under the fixed designation D6749; 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 (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method covers an alternative procedure for the determination of pour point of petroleum
products using an automatic apparatus.
1. Scope D4057Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers the determination of pour point
D4177Practice for Automatic Sampling of Petroleum and
of petroleum products by an automatic apparatus that applies a
Petroleum Products
slightly positive air pressure onto the specimen surface while
2.2 Energy Institute Standard:
the specimen is being cooled.
IP 15Test Method for Pour Point of Petroleum Products
1.2 This test method is designed to cover the range of
temperatures from −57 to +51°C; however, the range of
3. Terminology
temperatures included in the (1998) interlaboratory test pro-
3.1 Definitions:
gram only covered the temperature range from −51 to −11°C.
3.1.1 pour point, n—in petroleum products,lowesttempera-
1.3 Test results from this test method can be determined at
tureatwhichmovementofthetestspecimenisobservedunder
either 1 or 3°C testing intervals.
prescribed conditions of test.
1.4 This test method is not intended for use with crude oils.
3.2 Definitions of Terms Specific to This Standard:
NOTE 1—The applicability of this test method on residual fuel samples
3.2.1 air pressure, n—regulated slightly positive air pres-
has not been verified. For further information on the applicability, refer to
sure gently applied onto the specimen surface in the airtight
13.4.
test jar that causes upward movement of the specimen in the
1.5 The values stated in SI units are to be regarded as
communicating tube, which has one end inserted into the test
standard. No other units of measurement are included in this
specimen and the other end at atmospheric pressure.
standard.
3.2.2 no-flow point, n—in petroleum products, temperature
1.6 This standard does not purport to address all of the
ofthetestspecimenatwhichawaxcrystalstructureofthetest
safety concerns, if any, associated with its use. It is the
specimen or viscosity increase, or both, impedes movement of
responsibility of the user of this standard to establish appro-
thesurfaceofthetestspecimenundertheconditionsofthetest.
priate safety and health practices and determine the applica-
3.2.2.1 Discussion—The no-flow point occurs when, upon
bility of regulatory limitations prior to use.
cooling, the formation of wax crystal structures or viscosity
increase,orboth,hasprogressedtothepointwheretheapplied
2. Referenced Documents
observation device no longer detects movement under the
2.1 ASTM Standards:
conditions of the test. The preceding observation temperature,
D97Test Method for Pour Point of Petroleum Products
at which flow of the test specimen is last observed, is the pour
point.
This test method is under the jurisdiction of ASTM Committee D02 on
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
4. Summary of Test Method
D02.07 on Flow Properties.
Current edition approved Nov. 1, 2012. Published November 2012. Originally 4.1 After inserting the test jar containing the specimen into
approved in 2002. Last previous edition approved in 2007 as D6749–02 (2007).
the automatic pour point apparatus and initiating the test
DOI: 10.1520/D6749-02R12.
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 Energy Institute, 61 New Cavendish St., London, WIG 7AR,
the ASTM website. U.K., http://www.energyinst.org.uk.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6749 − 02 (2012)
program, the specimen is automatically heated to the desig- ing and reporting the pour point (see Fig. 1). The detail is
nated temperature and then cooled at a controlled rate. At described in Annex A1.
temperature intervals of 1 or 3°C, depending on the selection
6.2 Test Jar, clear cylindrical glass with a flat bottom with
made by the user prior to the test, a slightly positive air
an approximate capacity of 12 mL. Approximately 4.5 mL of
pressure is gently applied onto the surface of the specimen
sample specimen is contained when filled to the scribed line.
which is contained in an airtight test jar equipped with a
The test jar is fitted with a test jar cap assembly on its top to
communicatingtube.Sinceoneendofthecommunicatingtube
form an air chamber over the test specimen.
is inserted into the specimen while the other end is maintained
6.3 Test Jar Cap Assembly—Aplasticcapisinstalledontop
at atmospheric pressure, a small amount of downward move-
ofthetestjarwiththeprovisionofsealingair.Aglasstubewith
ment or deformation of the specimen surface, as a result of the
a metallic tip shall be inserted from underneath the plastic cap
application of air pressure, is observed by means of upward
intotheroundholeinthecenterofthetestjarcap.Thetopend
movement of the specimen in the communicating tube. This
oftheroundholeisconnectedtoanairpressuresensorbyway
upward movement of the specimen is detected by a pressure
of a vinyl tube. To supply air pressure to the specimen’s
sensor which is installed at the atmospheric end of the
surface, a vinyl tube connected to an air syringe is located
communicating tube. The lowest temperature at which defor-
adjacent to the glass tube through an orifice in the plastic cap.
mation of the specimen is observed upon application of air
When a specimen is to be tested, the test jar cap assembly is
pressure is recorded as the pour point in accordance with Test
installed on the test jar with the lower end of the glass tube
Method D6749.
insertedintothespecimeninthetestjar.Theglasstubeandthe
test jar form a communicating tube.Atemperature sensor in a
5. Significance and Use
smalldiametermetallicsheathshallbeinstalledinthecenterof
5.1 Thepourpointofapetroleumproductisanindexofthe
the glass tube.
lowest temperature of its utility for certain applications. Flow
6.4 Metallic Block Bath, a metallic block with a cylindrical
characteristics, like pour point, can be critical for the correct
hole to fit the test jar. The metallic block assembly shall have
operation of lubricating systems, fuel systems, and pipeline
operations.
5.2 Petroleum blending operations require precise measure-
ment of the pour point.
5.3 Test results from this test method can be determined at
either 1 or 3°C intervals.
5.4 This test method yields a pour point in a format similar
to Test Method D97/IP 15 when the 3°C interval results are
reported. However, when specification requires Test Method
D97/IP 15, do not substitute this test method.
NOTE 2—Since some users may wish to report their results in a format
similar to Test Method D97/IP 15 (in 3°C intervals), the precision data
were derived for the 3°C intervals. For statements on bias relative to Test
Method D97/IP 15, see 13.3.1.
5.5 This test method has better repeatability and reproduc-
ibility relative to Test Method D97/IP 15 as measured in the
1998 interlaboratory test program (see Section 13).
6. Apparatus
4,5
6.1 Automatic Apparatus —The automatic pour point ap-
paratus described in this test method is a microprocessor
controlled apparatus that is capable of heating and cooling a
specimen, applying air pressure onto the specimen’s surface,
detecting the specimen’s surface movement, and then comput-
Thesolesourceofsupplyoftheapparatusknowntothecommitteeatthistime
isTanaka model MPC series Pour PointAnalyzers available fromTanaka Scientific
Limited,Adachiku, Tokyo, Japan. Various models included in this model series are
differentiatedbytheircoolingcapacitiesornumberoftestheads,orboth.Ifyouare
aware of alternative suppliers, please provide this information to ASTM Interna-
tional Headquarters.Your comments will receive careful consideration at a meeting
of the responsible technical committee, which you may attend.
This pour point analyzer is covered by a patent. If you are aware of an
alternative(s) to the patented item, please attach to your ballot return a description
of the alternatives. All the suggestions will be considered by the committee. FIG. 1 Automatic Apparatus
D6749 − 02 (2012)
a provision for cooling/heating. A temperature sensor is em- thenentertheexpectedpourpoint(EPP).Whenthe3°Ctesting
bedded in the metallic block to monitor its temperature. interval is chosen, the EPP needs to be a multiple of 3°C.
11.4 Start the test program. The sample is automatically
7. Reagents and Materials
preheatedbytheautomaticapparatusto45°CortoEPP+9°C,
7.1 Cleaning Agents,capableofcleaninganddryingthetest
whichever is higher, but no higher than 70°C, by maintaining
jar,temperaturesensor,andglasstubeaftereachtest.Chemical
the bath temperature at 48°C or EPP + 12°C, whichever is
agents such as alcohol, petroleum-based solvents, and acetone
higher.
have been found suitable to use. ( Warning—Flammable.)
11.5 After the preheating is completed, the specimen is
(Warning—May be harmful by itself or when evaporated.)
cooled down automatically.
11.5.1 The metallic block bath is cooled down at a rate of 3
8. Sampling
to 4°C/min, to the EPP + 40°C.
8.1 Obtain a sample in accordance with Practice D4057 or
11.5.2 From the EPP + 40°C to the no-flow point, the
by Practice D4177.
metallic block bath is cooled at a rate of 0.8 to 1.1°C/min.
8.2 Samples of very viscous materials may be warmed until
11.6 As the specimen temperature reaches a predetermined
they are reasonably fluid before they are transferred; however,
temperature, which is dependent on the EPP, the automatic
no sample shall be heated more than is absolutely necessary.
apparatus starts testing for no-flow state by applying air
The sample shall not be heated and transferred into the test jar
pressure to the specimen surface at the programmed testing
unless its temperature is 70°C or lower.
interval. When the specimen is still in a fluid state, the
NOTE 3—In the event the sample has been heated above this
specimen level moves up in the glass tube as air pressure is
temp
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