ASTM D8221-18
(Practice)Standard Practice for Determining the Calculated Methane Number (MNC) of Gaseous Fuels Used in Internal Combustion Engines
Standard Practice for Determining the Calculated Methane Number (MN<inf>C</inf>) of Gaseous Fuels Used in Internal Combustion Engines
SIGNIFICANCE AND USE
5.1 The methane number (MN) is a measure of the resistance of the gaseous fuel to autoignition (knock) when used in an internal combustion engine. The relative merits of gaseous fuels from different sources and having different compositions can be compared readily on the basis of their methane numbers. Therefore, the calculated methane number (MNC) is used as a parameter for determining the suitability of a gaseous fuel for internal combustion engines in both mobile and stationary applications.
SCOPE
1.1 This practice covers the method to determine the calculated methane number (MNC) of a gaseous fuel used in internal combustion engines. The basis for the method is a dynamic link library (DLL) suitable for running on computers with Microsoft Windows operating systems.
1.2 This practice pertains to commercially available natural gas products that have been processed and are suitable for use in internal combustion engines. These fuels can be from traditional geological or renewable sources and include pipeline gas, compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG), and renewable natural gas (RNG) as defined in Section 3.
1.3 The calculation method within this practice is based on the MWM Method as defined in EN 16726, Annex A.2 The calculation method is an optimization algorithm that uses varying sequences of ternary and binary gas component tables generated from the composition of a gaseous fuel sample.3 Both the source code and a Microsoft Excel-based calculator are available for this method.
1.4 This calculation method applies to gaseous fuels comprising of hydrocarbons from methane to hexane and greater (C6+); carbon monoxide; hydrogen; hydrogen sulfide; nitrogen; and carbon dioxide. The calculation method addresses pentanes (C5) and higher hydrocarbons and limits the individual volume fraction of C5 and C6+ to 3 % each and a combined total of 5 %. (See EN 16726, Annex A.) The calculation method is performed on a dry, oxygen-free basis.
1.5 Units—The values stated in SI units are to be regarded as standard. Other units of measurement included in this standard practice are for reference only.
1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 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.
General Information
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Standards Content (Sample)
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Designation: D8221 − 18
Standard Practice for
Determining the Calculated Methane Number (MN )of
C
1
Gaseous Fuels Used in Internal Combustion Engines
This standard is issued under the fixed designation D8221; 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 1.5 Units—The values stated in SI units are to be regarded
as standard. Other units of measurement included in this
1.1 This practice covers the method to determine the calcu-
standard practice are for reference only.
latedmethanenumber(MN )ofagaseousfuelusedininternal
C
1.6 This standard does not purport to address all of the
combustion engines. The basis for the method is a dynamic
safety concerns, if any, associated with its use. It is the
link library (DLL) suitable for running on computers with
responsibility of the user of this standard to establish appro-
Microsoft Windows operating systems.
priate safety, health, and environmental practices and deter-
1.2 This practice pertains to commercially available natural
mine the applicability of regulatory limitations prior to use.
gas products that have been processed and are suitable for use
1.7 This international standard was developed in accor-
in internal combustion engines. These fuels can be from
dance with internationally recognized principles on standard-
traditional geological or renewable sources and include pipe-
ization established in the Decision on Principles for the
line gas, compressed natural gas (CNG), liquefied natural gas
Development of International Standards, Guides and Recom-
(LNG), liquefied petroleum gas (LPG), and renewable natural
mendations issued by the World Trade Organization Technical
gas (RNG) as defined in Section 3.
Barriers to Trade (TBT) Committee.
1.3 The calculation method within this practice is based on
2. Referenced Documents
2
the MWM Method as defined in EN 16726, Annex A. The
4
2.1 ASTM Standards:
calculation method is an optimization algorithm that uses
E29 Practice for Using Significant Digits in Test Data to
varying sequences of ternary and binary gas component tables
3
Determine Conformance with Specifications
generated from the composition of a gaseous fuel sample.
5
Both the source code and a Microsoft Excel-based calculator 2.2 CEN Standard:
EN 16726 Gas infrastructure—Quality of gas—Group H,
are available for this method.
Annex A—Calculation of methane number of gaseous
1.4 This calculation method applies to gaseous fuels com-
fuels for engines
prising of hydrocarbons from methane to hexane and greater
6
2.3 ISO Standard:
(C6+); carbon monoxide; hydrogen; hydrogen sulfide; nitro-
ISO 14912 Gas analysis—Conversion of gas mixture com-
gen; and carbon dioxide. The calculation method addresses
position data
pentanes (C5) and higher hydrocarbons and limits the indi-
2.4 ASTM Adjuncts:
vidual volume fraction of C5 and C6+ to 3 % each and a
7
ASTM_D8221_mzdll_ver2.32.0.dll
combined total of 5 %. (See EN 16726, Annex A.) The
7
ASTM_D8221_MNc_Method_ver1.32.0.xlsb
calculation method is performed on a dry, oxygen-free basis.
3. Terminology
3.1 Definitions:
1
This practice is under the jurisdiction of ASTM Committee D03 on Gaseous
Fuels and is the direct responsibility of Subcommittee D03.03 on Determination of
Heating Value and Relative Density of Gaseous Fuels.
4
Current edition approved Sept. 1, 2018. Published October 2018. DOI: 10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D8221-18. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
European Standards (ENs) are documents that have been ratified by one of the Standards volume information, refer to the standard’s Document Summary page on
three European Standardization Organizations (ESOs), CEN, CENELEC or ETSI; the ASTM website.
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recognized as competent in the area of voluntary technical standardization as for the Available from European Committee for Standardization (CEN), Avenue
EU Regulation 1025/2012. EN16726 was developed by the Technical Committee Marnix 17, B-1000, Brussels, Belgium, http://www.cen.eu.
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CEN/TC 234. Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
3
Leiker,M.,Christoph,K.,Rankl,M.,Cartellieri,W.,Pfeifer,U.,“Evaluationof 4th Floor, New York, NY 10036, http://www.ansi.org.
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Antiknocking Property of Gaseous Fuels by Means of Methane Number and its Available from ASTM International Headquarters. Order Adjunct No.
Practical Application to Gas Engines,” ASME, 72-DGP-4, 1972. ADJD822118-EA. Original adjunct produced in 2018.
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