ASTM D4928-11
(Test Method)Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration
Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration
SIGNIFICANCE AND USE
A knowledge of the water content of crude oil is important in the refining, purchase, sale, or transfer of crude oils.
SCOPE
1.1 This test method covers the determination of water in the range from 0.02 to 5 mass or volume % in crude oils. Mercaptan (RSH) and sulfide (S− or H2S) as sulfur are known to interfere with this test method, but at levels of less than 500 μg/g (ppm), the interference from these compounds is insignificant (see Section 5).
1.2 This test method can be used to determine water in the 0.005 to 0.02 mass % range, but the effects of the mercaptan and sulfide interference at these levels has not been determined.
1.3 This test method is intended for use with standard commercially available coulometric Karl Fischer reagent.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 hazard statements, see Section 7.
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Designation: D4928 − 11
Manualof Petroleum Measurement Standards (MPMS), Chapter 10.9
Designation: 386/99
Standard Test Method for
1
Water in Crude Oils by Coulometric Karl Fischer Titration
This standard is issued under the fixed designation D4928; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope* D4057Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers the determination of water in
D4177Practice for Automatic Sampling of Petroleum and
the range from 0.02 to 5 mass or volume % in crude oils.
− Petroleum Products
Mercaptan (RSH) and sulfide (S or H S) as sulfur are known
2
D5854Practice for Mixing and Handling of Liquid Samples
to interfere with this test method, but at levels of less than
of Petroleum and Petroleum Products
500µg/g (ppm), the interference from these compounds is
E203Test Method for Water Using Volumetric Karl Fischer
insignificant (see Section 5).
Titration
1.2 This test method can be used to determine water in the
3
2.2 API Standards:
0.005 to 0.02 mass % range, but the effects of the mercaptan
MPMS Chapter 8.1Practice for Manual Sampling of Petro-
and sulfide interference at these levels has not been deter-
leum and Petroleum Products (ASTM Practice D4057)
mined.
MPMS Chapter 8.2Practice for Automatic Sampling of
1.3 This test method is intended for use with standard
Petroleum and Petroleum Products (ASTM Practice
commercially available coulometric Karl Fischer reagent.
D4177)
MPMS Chapter 8.3Practice for Mixing and Handling of
1.4 The values stated in SI units are to be regarded as
Liquid Samples of Petroleum and Petroleum Products
standard. No other units of measurement are included in this
(ASTM Practice D5854)
standard.
1.5 This standard does not purport to address all of the
3. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1 After homogenizing the crude oil with a mixer, an
aliquot is injected into the titration vessel of a Karl Fischer
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific hazard apparatus in which iodine for the Karl Fischer reaction is
generatedcoulometricallyattheanode.Whenallthewaterhas
statements, see Section 7.
been titrated, excess iodine is detected by an electrometric
2. Referenced Documents end-point detector and the titration is terminated. Based on the
2 stoichiometry of the reaction, one mole of iodine reacts with
2.1 ASTM Standards:
one mole of water, thus the quantity of water is proportional to
D1193Specification for Reagent Water
the total integrated current according to Faraday’s Law.
3.2 The precision of this test method is critically dependent
1
This test method is under the jurisdiction of ASTM Committee D02 on
ontheeffectivenessofthehomogenizationstep.Theefficiency
Petroleum Products and Lubricants and theAPI Committee on Petroleum Measure-
of the mixer used to achieve a homogeneous sample is
ment and is the direct responsibility of Subcommittee D02.02 /COMQ on Hydro-
determined by the procedure given in Practice D5854 (API
carbon Measurement for Custody Transfer (Joint ASTM-API).
Current edition approved June 1, 2011. Published August 2011. Originally MPMS Chapter 8.3).
approved in 1989. Last previous edition approved in 2010 as D4928–00 (2010).
DOI: 10.1520/D4928-11.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Published as Manual of Petroleum Standards. Available from American
Standards volume information, refer to the standard’s Document Summary page on Petroleum Institute (API), 1220 L. St., NW, Washington, DC 20005-4070, http://
the ASTM website. www.api.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D4928 − 11
3.3 Two procedures are provided for the determination of inserted through the inlet port septum. This syringe is used in
water in crude oils. In one procedure, a weighed aliquot of the calibration step (Section 10). It should be of suitable
sample is injected into the titration vessel and the mass % of graduations for readings to the nearest 0.1 µL or better.
water is determined. The other procedure provides for the 6.3.1.2 Syringes,
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D4928–00 (Reapproved 2010) Designation:D4928–11
Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 10.9
Designation: 386/99
Standard Test Method for
1
Water in Crude Oils by Coulometric Karl Fischer Titration
This standard is issued under the fixed designation D4928; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope*
1.1 This test method covers the determination of water in the range from 0.02 to 5 mass or volume % in crude oils. Mercaptan
−
(RSH) and sulfide (S or H S) as sulfur are known to interfere with this test method, but at levels of less than 500µg/g (ppm),
2
the interference from these compounds is insignificant (see Section 5).
1.2 This test method can be used to determine water in the 0.005 to 0.02 mass % range, but the effects of the mercaptan and
sulfide interference at these levels has not been determined.
1.3 This test method is intended for use with standard commercially available coulometric Karl Fischer reagent.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 hazard statements, see Section 7.
2. Referenced Documents
2
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
E203 Test Method for Water Using Volumetric Karl Fischer Titration
3
2.2 API Standards:
MPMS Chapter 8.1 Practice for Manual Sampling of Petroleum and Petroleum Products (ASTM Practice D4057)
MPMS Chapter 8.2 Practice for Automatic Sampling of Petroleum and Petroleum Products (ASTM Practice D4177)
MPMSChapter8.3 PracticeforMixingandHandlingofLiquidSamplesofPetroleumandPetroleumProducts(ASTMPractice
D5854)
3. Summary of Test Method
3.1 After homogenizing the crude oil with a mixer, an aliquot is injected into the titration vessel of a Karl Fischer apparatus
inwhichiodinefortheKarlFischerreactionisgeneratedcoulometricallyattheanode.Whenallthewaterhasbeentitrated,excess
iodineisdetectedbyanelectrometricend-pointdetectorandthetitrationisterminated.Basedonthestoichiometryofthereaction,
onemoleofiodinereactswithonemoleofwater,thusthequantityofwaterisproportionaltothetotalintegratedcurrentaccording
to Faraday’s Law.
1
This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products and Lubricants and theAPI Committee on Petroleum Measurement, and is
the direct responsibility of Subcommittee D02.02.10 on Sediment and Water (API MPMS Chapter 10.0).
Current edition approved June 1, 2010.2011. Published July 2010.August 2011. Originally approved in 1989. Last previous edition approved in 20052010 as D4928–00
(2005).(2010). DOI: 10.1520/D4928-00R10.10.1520/D4928-11.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Published as Manual of Petroleum Standards.Available fromAmerican Petroleum Institute (API), 1220 L. St., NW, Washington, DC 20005-4070, http://www.api.org.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D4928–11
3.2 The precision of this test method is critically dependent on the effectiveness of the homogenization step. The efficiency of
the mixer used to achieve a homogeneous sample is determined by the procedure given in Practice D5854 (API MPMS Chapter
8.3).
3.3 Two procedures are provided for the determination of water in crude oils. In one procedure, a weighed aliquot of sample
isinjectedintothetitrationvesselandthemass%ofwa
...
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