ASTM D2598-21 - 1.4.2021
 
Significance and Use

4.1?Vapor pressure is an important specification property of commercial propane, special duty propane, propane/butane mixtures, and commercial butane that assures adequate vaporization, safety, and compatibility with commercial appliances. Relative density, while not a specification criterion, is necessary for determination of filling densities and custody transfer. The motor octane number (MON) is useful in determining the products' suitability as a fuel for internal combustion engines.

 
1. Scope

1.1?This practice covers, by compositional analysis, the approximate determination of the following physical characteristics of commercial propane, special-duty propane, commercial propane/butane mixtures, and commercial butane (covered by Specification D1835): vapor pressure, relative density, and motor octane number (MON).

1.1.1?This practice is not applicable to any product exceeding specifications for nonvolatile residues. (See Test Method D2158.)

1.1.2?For calculating motor octane number, this practice is applicable only to mixtures containing 20 % or less of propene.

1.1.3?For calculated motor octane number, this practice is based on mixtures containing only components shown in Table 1.

1.2?The values stated in SI units are to be regarded as standard.

1.2.1?Exceptions:?

1.2.1.1?Non-SI units in parentheses are given for information only.

1.2.1.2?Motor octane number and relative density are given in MON numbers and dimensionless units, respectively.

1.3?This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

 
2. Referenced Documents

D1267-23

Standard Test Method for Gauge Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method)

D1657-22e1

Standard Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Hydrometer (Includes all amendments and changes 3/14/2023).

D1835-22

Standard Specification for Liquefied Petroleum (LP) Gases

D2163-23e1

Standard Test Method for Determination of Hydrocarbons in Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by Gas Chromatography (Includes all amendments and changes 4/27/2023).

D2421-21e1

Standard Practice for Interconversion of Analysis of C5 and Lighter Hydrocarbons to Gas-Volume, Liquid-Volume, or Mass Basis (Includes all amendments and changes 6/16/2021).

GPSA Engineering Data Book, 12th Edition, 2004

D2158-21

Standard Test Method for Residues in Liquefied Petroleum (LP) Gases