EN ISO 12213-2:2005
(Main)Natural gas - Calculation of compression factor - Part 2: Calculation using molar-composition analysis (ISO 12213-2:1997)
Natural gas - Calculation of compression factor - Part 2: Calculation using molar-composition analysis (ISO 12213-2:1997)
Erdgas - Berechnung von Realgasfaktoren - Teil 2: Berechnungen basierend auf einer molaren Gasanalyse als Eingangsgröße (ISO 12213-2:1997)
Gaz naturel - Calcul du facteur de compression - Partie 2: Calcul à partir de l'analyse de la composition molaire (ISO 12213-2:1997)
Zemeljski plin – Izračun kompresijskega faktorja – 2. del: Izračun na podlagi molarnih-kompozicijskih analiz (ISO 12213-2:1997)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2005
=HPHOMVNLSOLQ±,]UDþXQNRPSUHVLMVNHJDIDNWRUMD±GHO ,]UDþXQQDSRGODJL
PRODUQLKNRPSR]LFLMVNLKDQDOL] ,62
Natural gas - Calculation of compression factor - Part 2: Calculation using molar-
composition analysis (ISO 12213-2:1997)
Erdgas - Berechnung von Realgasfaktoren - Teil 2: Berechnungen basierend auf einer
molaren Gasanalyse als Eingangsgröße (ISO 12213-2:1997)
Gaz naturel - Calcul du facteur de compression - Partie 2: Calcul a partir de l'analyse de
la composition molaire (ISO 12213-2:1997)
Ta slovenski standard je istoveten z: EN ISO 12213-2:2005
ICS:
75.060 Zemeljski plin Natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 12213-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2005
ICS 75.060
English version
Natural gas - Calculation of compression factor - Part 2:
Calculation using molar-composition analysis (ISO 12213-
2:1997)
Gaz naturel - Calcul du facteur de compression - Partie 2: Erdgas - Berechnung von Realgasfaktoren - Teil 2:
Calcul à partir de l'analyse de la composition molaire (ISO Berechnungen basierend auf einer molaren Gasanalyse als
12213-2:1997) Eingangsgröße (ISO 12213-2:1997)
This European Standard was approved by CEN on 17 April 2005.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
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Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12213-2:2005: E
worldwide for CEN national Members.
Foreword
The text of ISO 12213-2:1997 has been prepared by Technical Committee ISO/TC 193 "Natural
gas” of the International Organization for Standardization (ISO) and has been taken over as EN
ISO 12213-2:2005 by CMC.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by November 2005, and conflicting national
standards shall be withdrawn at the latest by November 2005.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 12213-2:1997 has been approved by CEN as EN ISO 12213-2:2005 without any
modifications.
INTERNATIONAL ISO
STANDARD 12213-2
First edition
1997-12-01
Natural gas — Calculation of compression
factor —
Part 2:
Calculation using molar-composition analysis
Gaz naturel — Calcul du facteur de compression —
Partie 2: Calcul par analyse de la composition molaire
A
Reference number
ISO 12213-2:1997(E)
ISO 12213-2:1997(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Definitions . 1
4 Method of calculation . 2
4.1 Principle . 2
4.2 The AGA8-92DC equation . 2
4.3 Input variables . 3
4.4 Ranges of application . 3
4.5 Uncertainty . 4
5 Suppliers of computer programmes . 6
Annexes
A Symbols and units . 7
B Description of the AGA8-92DC method . 9
C Example calculations . 15
D Pressure and temperature conversion factors . 16
E Performance over wider ranges of application . 17
F Subroutines in Fortran for the AGA8-92DC method . 21
G Bibliography . 28
© ISO 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet central@iso.ch
X.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
ii
©
ISO ISO 12213-2:1997(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national standards bodies (ISO member bodies). The work of
preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be represented
on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 12213-2 was prepared by Technical Committee
ISO/TC 193, Natural gas, Subcommittee SC 1, Analysis of natural gas.
ISO 12213 consists of the following parts, under the general title Natural
gas — Calculation of compression factor:
— Part 1: Introduction and guidelines
— Part 2: Calculation using molar-composition analysis
— Part 3: Calculation using physical properties
Annexes A to D form an integral part of this part of ISO 12213. Annexes E
to G are for information only.
iii
©
INTERNATIONAL STANDARD ISO ISO 12213-2:1997(E)
Natural gas — Calculation of compression factor —
Part 2:
Calculation using molar-composition analysis
1 Scope
This International Standard specifies methods for the calculation of compression factors of natural gases, natural
gases containing a synthetic admixture and similar mixtures at conditions under which the mixture can exist only as
a gas.
This part of ISO 12213 specifies a method for the calculation of compression factors when the detailed composition
of the gas by mole fractions is known, together with the relevant pressures and temperatures.
The method is applicable to pipeline quality gases within the ranges of pressure p and temperature T at which
transmission and distribution operations normally take place, with an uncertainty of about – 0,1 %. It can be applied,
with greater uncertainty, to wider ranges of gas composition, pressure and temperature (see annex E).
More detail concerning the scope and field of application of the method is given in part 1 of this International
Standard.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
ISO 12213. At the time of publication, the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of ISO 12213 are encouraged to investigate the possibility of applying the
most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid
International Standards.
ISO 31-3:1992, Quantities and units — Part 3: Mechanics.
ISO 31-4:1992, Quantities and units — Part 4: Heat.
ISO 6976:1995, Natural gas — Calculation of calorific values, density, relative density and Wobbe index from
composition.
ISO 12213-1:1997, Natural gas — Calculation of compression factor — Part 1: Introduction and guidelines.
3 Definitions
All definitions relevant to the use of this part of ISO 12213 are given in part 1.
©
ISO
ISO 12213-2:1997(E)
4 Method of calculation
4.1 Principle
The method recommended uses an equation based on the concept that pipeline quality natural gas may be
uniquely characterized for calculation of its volumetric properties by component analysis. This analysis, together
with the pressure and temperature, are used as input data for the method.
The method uses a detailed molar-composition analysis in which all constituents present in amounts exceeding a
mole fraction of 0,000 05 should be represented. Typically, this includes all alkane hydrocarbons up to about C or
C together with nitrogen, carbon dioxide and helium.
For other gases, additional components such as water vapour, hydrogen sulfide and ethylene need to be taken into
consideration (see reference [1] in annex G).
For manufactured gases, hydrogen and carbon monoxide are also likely to be significant components.
4.2 The AGA8-92DC equation
The compression factor is determined using the AGA8 detailed characterization equation (denoted hereafter as the
[1]
AGA8-92DC equation). This is an extended virial-type equation. The equation is described in AGA Report No. 8 . It
may be written as
18 58
kb k
nn n
* *
ZB=+1 rr− C + Cb −ckr r exp−cr . . . (1)
mr∑∑n n()nnnr r( nr)
nn==13 13
where
Z is the compression factor;
B is the second virial coefficient;
r is the molar density (moles per unit volume);
m
r is the reduced density;
r
b , c , k are constants (see table B.1);
n n n
*
are coefficients which are functions of temperature and composition.
C
n
The reduced density r is related to the molar density r by the equation
r m
rr=K . . . (2)
rm
where K is a mixture size parameter.
The molar density can be written as
r =pZRT . . . (3)
()
m
where
p is the absolute pressure;
R is the universal gas constant;
T is the absolute temperature.
*
Z is calculated as follows: first the values of B and C (n = 13 to 58) are calculated, using relationships given in
n
annex B. Equations (1) and (3) are then solved simultaneously for r and Z by a suitable numerical method (see
m
figure B.1).
©
ISO
ISO 12213-2:1997(E)
4.3 Input variables
The input variables required for use with the AGA8-92DC equation are the absolute pressure, absolute temperature
and molar composition.
The composition is required, by mole fraction, of the following components: nitrogen, carbon dioxide, argon,
methane, ethane, propane, n-butane, methyl-2-propane (iso-butane), n-pentane, methyl-2-butane (iso-pentane),
hexanes, heptanes, octanes, nonanes, decanes, hydrogen, carbon monoxide, hydrogen sulfide, helium, oxygen
and water.
NOTE — If the mole fractions of the heptanes, octanes, nonanes and decanes are unknown, then use of a composite C
6+
fraction may be acceptable. The user should carry out a sensitivity analysis in order to test whether a particular approximation
of this type degrades the result.
All components with mole fractions greater than 0,000 05 shall be accounted for. Trace components (such as
ethylene) shall be treated as given in table 1.
If the composition is known by volume fractions, these shall be converted to mole fractions using the method given
in ISO 6976. The sum of all mole fractions shall be unity to within 0,000 1.
4.4 Ranges of application
4.4.1 Pipeline quality gas
The ranges of application for pipeline quality gas are as defined below:
absolute pressure 0 MPa < p < 12 MPa
temperature 263 K < T < 338 K
3 3
superior calorific value 30 MJ�m < H < 45 MJ�m
S
relative density 0,55 < d < 0,80
The mole fractions of the natural-gas components shall be within the following ranges:
methane 0,7 < x < 1,00
CH
nitrogen 0 < x < 0,20
N
carbon dioxide 0 < x < 0,20
CO
ethane 0 < x < 0,10
C H
2 6
propane 0 < x < 0,035
C H
3 8
butanes 0 < x < 0,015
C4H10
pentanes 0 < x < 0,005
C H
5 12
hexanes 0 < x < 0,001
C
heptanes 0 < x < 0,000 5
C
octanes plus 0 < x < 0,000 5
C
8+
higher hydrocarbons
hydrogen 0 < x < 0,10
H
carbon monoxide 0 < x < 0,03
CO
helium 0 < x < 0,005
He
water 0 < x < 0,000 15
H O
Any component for which x is less than 0,000 05 can be neglected.
i
Minor and trace components are listed in table 1.
©
ISO
ISO 12213-2:1997(E)
Table 1 — Minor and trace components
Minor or trace component Assigned component
Oxygen oxygen
Argon argon
Hydrogen sulfide hydrogen sulfide
Ethylene, acetylene carbon dioxide
Propylene, propadiene propane
Butenes, butadienes n-butane
Neo-pentane, pentenes, benzene, cyclopentane n-pentane
All C -isomers, cyclohexane, ethylbenzene, xylenes n
...
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