ASTM D7756-11

Standard Test Method for Residues in Liquefied Petroleum (LP) Gases by Gas Chromatography with Liquid, On-Column Injection

SIGNIFICANCE AND USE
Control over the residue content as specified in Specification D1835 is of considerable importance in end-use applications of LPG. Oily residue in LPG is contamination which can occur during production, transportation, or storage.
This test method is quicker and much more sensitive than manual methods, such as Test Method D2158, which is based on evaporation of large sample volumes followed by visual or gravimetric estimation of residue content.
This test method provides enhanced sensitivity in measurements of heavier (oily) residues, with a quantification limit of 10 mg/kg total residue.
This test method gives both quantitative results and information about contaminant composition such as boiling point range and fingerprint, which can be very useful in tracing the source of a particular contaminant.
SCOPE
1.1 This test method covers the determination, by gas chromatography, of soluble hydrocarbon materials, sometimes called “oily residue,” which can be present in Liquefied Petroleum (LP) Gases and which are substantially less volatile than the LPG product.
1.2 This test method quantifies, in the range of 10 to 600 mg/kg (ppm mass), the residue with a boiling point between 174°C and 522°C (C10 to C40) in LPG. Higher boiling materials, or materials that adhere permanently to the chromatographic column, will not be detected.
1.3 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
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.

General Information

• Status: Historical
• Publication Date: 30-Sep-2011
• ICS: 75.160.30 - Gaseous fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.H0 - Liquefied Petroleum Gas

Relations

• Referred By: ASTM D2158-21 - Standard Test Method for Residues in Liquefied Petroleum (LP) Gases
• Effective Date: 01-Oct-2011
• Referred By: ASTM D7901-20 - Standard Specification for Dimethyl Ether for Fuel Purposes
• Effective Date: 01-Oct-2011
• Referred By: ASTM D1835-22 - Standard Specification for Liquefied Petroleum (LP) Gases
• Effective Date: 01-Oct-2011

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7756 −11
StandardTest Method for
Residues in Liquefied Petroleum (LP) Gases by Gas
1
Chromatography with Liquid, On-Column Injection
This standard is issued under the fixed designation D7756; 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 D2598 Practice for Calculation of Certain Physical Proper-
ties of Liquefied Petroleum (LP) Gases from Composi-
1.1 This test method covers the determination, by gas
tional Analysis
chromatography, of soluble hydrocarbon materials, sometimes
D3700 Practice for Obtaining LPG Samples Using a Float-
called “oily residue,” which can be present in Liquefied
ing Piston Cylinder
Petroleum (LP) Gases and which are substantially less volatile
D6299 Practice for Applying Statistical Quality Assurance
than the LPG product.
and Control Charting Techniques to Evaluate Analytical
1.2 This test method quantifies, in the range of 10 to 600
Measurement System Performance
mg/kg (ppm mass), the residue with a boiling point between
D6667 Test Method for Determination of Total Volatile
174°C and 522°C (C to C ) in LPG. Higher boiling
10 40
Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum
materials, or materials that adhere permanently to the chro-
Gases by Ultraviolet Fluorescence
matographic column, will not be detected.
E355 Practice for Gas ChromatographyTerms and Relation-
1.3 Units—The values stated in SI units are to be regarded ships
E594 Practice for Testing Flame Ionization Detectors Used
as standard. The values given in parentheses are for informa-
tion only. in Gas or Supercritical Fluid Chromatography
1.4 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1 Definitions of Terms Concerning Chromatography—
priate safety and health practices and determine the applica-
This test method makes reference to many common gas
bility of regulatory limitations prior to use.
chromatographicprocedures,terms,andrelationships.Detailed
definitions of these can be found in Practices E355 and E594.
2. Referenced Documents
2
3.2 Definitions of Terms Concerning Liquefied Petroleum
2.1 ASTM Standards:
Gases—This test method makes reference to the definitions of
D1265 Practice for Sampling Liquefied Petroleum (LP)
liquefied petroleum gases as described in Specification D1835.
Gases, Manual Method
D1835 Specification for Liquefied Petroleum (LP) Gases 3.3 Definitions of Terms Specific to This Standard:
D2158 Test Method for Residues in Liquefied Petroleum
3.3.1 high pressure liquefied gas injector, n—Sample intro-
(LP) Gases
duction device which injects liquefied gas samples under
D2163 Test Method for Analysis of Liquefied Petroleum
pressure and at room temperature directly onto the chromato-
(LP) Gases and Propene Concentrates by Gas Chromatog-
graphic column thereby maintaining the sample in liquid phase
raphy
during the injection process.
D2421 Practice for Interconversion of Analysis of C and
5
3.3.2 pressure station, n—Device that supplies high pres-
Lighter Hydrocarbons to Gas-Volume, Liquid-Volume, or
sure nitrogen to a suitable sample cylinder and therefore
Mass Basis
maintains sample in the liquid phase during the injection
procedure.
1
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
4. Summary of Test Method
D02.H0 on Liquefied Petroleum Gas.
Current edition approved Oct. 1, 2011. Published November 2011. DOI:10.1520/
4.1 A sample cylinder of LPG is pressurized to 2500 kPa
D7756-11
2
(363 psi) using nitrogen or helium.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4.2 TheinjectionsystemisflushedwithLPGinliquidphase
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. at room temperature.
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D7756 − 11
4.3 After flushing, the injection device is routed to the GC 6. Apparatus
injector port and LPG (25 milliseconds activation time equiva-
6.1 Gas Chromatograph (GC)—Gas chromatographic in-
lent to 30 µL) is introduced via a high pressure valve and
strument equipped with a Large Volume Cold on-Column
needle which is inserted into a large volume cold on-column
Injector (LVOCI), a linear temperature programmable column
injector.
oven
...