Significance and Use

The component distribution of hydrocarbon liquid mixtures is often required as a specification analysis for these materials. Wide use of these hydrocarbon mixtures as chemical feedstocks or as fuel require precise compositional data to ensure uniform quality of the reaction product. In addition, custody transfer of these products is often made on the basis of component analyses of liquid mixtures.

The component distribution data of hydrocarbon mixtures can be used to calculate physical properties, such as specific gravity, vapor pressure, molecular weight, and other important properties. Precision and accuracy of compositional data are extremely important when these data are used to calculate physical properties of these products.

Note 3Specifications for some hydrocarbon liquid mixtures, such as LPG, may be based on composition measured by Test Method . Nitrogen and carbon dioxide determinations are not within the scope of Test Method .

1. Scope

1.1 This test method covers the analysis of demethanized liquid hydrocarbon streams containing nitrogen/air and carbon dioxide, and purity products, such as an ethane/propane mix that fall within the compositional ranges listed in Table 1. This test method is limited to mixtures containing less than 5 mol % of heptanes and heavier fractions.

1.2 The heptanes and heavier fractions, when present in the sample, are analyzed by either ( 1 ) reverse flow of carrier gas after n -hexane and peak grouping or ( 2 ) precut column to elute heptanes and heavier first as a single peak. For purity mixes without heptanes and heavier, no reverse of carrier flow is required. ( Caution In the case of samples with a relatively large C ₆₊ or C ₇₊ fraction and where precise results are important, it is desirable to determine the molecular weight (or other pertinent physical properties) of these fractions. Since this test method makes no provision for determining physical properties, the physical properties needed can be determined by an extended analysis or agreed to by the contracting parties.)

1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

Note 1Annex A2 states values in manometric units, which are to be regarded as the standard in that section. Approximate SI units (from conversion) are given in parentheses.

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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1265 Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method

D2163 Test Method for Analysis of Liquefied Petroleum (LP) Gases and Propene Concentrates by Gas Chromatography

D3700 Practice for Obtaining LPG Samples Using a Floating Piston Cylinder

D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance

D6849 Practice for Storage and Use of Liquefied Petroleum Gases (LPG) in Sample Cylinders for LPG Test Methods

GPA Standard

Keywords

carbon dioxide; chromatography; demethanized hydrocarbons; hydrocarbon composition; liquefied petroleum gases; natural gas liquids; nitrogen; Carbon dioxide; Chemical analysis--petroleum products; Composition analysis--petroleum products; Demethanized hydrocarbons; Gas chromatography (GC)--petroleum products; Hydrocarbons; LPG (liquefied petroleum gases); Natural gas-liquid (NGL) mixtures; Nitrogen content--petroleum products;

ICS Code

ICS Number Code 75.080 (Petroleum products in general)

DOI: 10.1520/D2597-10

ASTM International is a member of CrossRef.

ASTM D2597