SIST EN ISO 18453:2006
(Main)Natural gas - Correlation between water content and water dew point (ISO 18453:2004)
Natural gas - Correlation between water content and water dew point (ISO 18453:2004)
ISO 18453:2004 specifies a method to provide users with a reliable mathematical relationship between water content and water dew point in natural gas when one of the two is known. The calculation method, developed by GERG; is applicable to both the calculation of the water content and the water dew point.
ISO 18453:2004 gives the uncertainty for the correlation but makes no attempt to quantify the measurement uncertainties.
Erdgas - Beziehung zwischen Wassergehalt und Taupunkt (ISO 18453:2004)
Diese Internationale Norm legt ein mathematisches Verfahren fest, mit dem der Anwender den Wassergehalt oder den Wasser-Taupunkt eines Erdgases ermitteln kann, wenn der jeweils andere Wert bekannt ist.
Diese Internationale Norm beschreibt die Unsicherheit der Beziehung, macht aber keinen Versuch zur Quantifizierung der Messunsicherheiten.
Gaz naturel - Corrélation entre la teneur en eau et le point de rosée eau (ISO 18453:2004)
L'ISO 18453:2004 spécifie une méthode pour fournir à l'utilisateur une relation mathématique fiable entre la teneur en eau et le point de rosée eau du gaz naturel, lorsque l'une des deux valeurs est connue. La méthode de calcul, mise au point par le GERG, est applicable aussi bien pour calculer la teneur en eau que le point de rosée eau.
L'ISO 18453:2004 donne l'incertitude pour la corrélation, mais n'a pas pour but de quantifier les incertitudes de mesure.
Zemeljski plin – Korelacija med deležem vode in vodnim rosiščem (ISO 18453:2004)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2006
=HPHOMVNLSOLQ±.RUHODFLMDPHGGHOHåHPYRGHLQYRGQLPURVLãþHP ,62
Natural gas - Correlation between water content and water dew point (ISO 18453:2004)
Erdgas - Beziehung zwischen Wassergehalt und Taupunkt (ISO 18453:2004)
Gaz naturel - Corrélation entre la teneur en eau et le point de rosée eau (ISO
18453:2004)
Ta slovenski standard je istoveten z: EN ISO 18453:2005
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 18453
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2005
ICS 75.060
English Version
Natural gas - Correlation between water content and water dew
point (ISO 18453:2004)
Gaz naturel - Corrélation entre la teneur en eau et le point Erdgas - Beziehung zwischen Wassergehalt und Taupunkt
de rosée eau (ISO 18453:2004) (ISO 18453:2004)
This European Standard was approved by CEN on 7 October 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,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
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 18453:2005: E
worldwide for CEN national Members.
Foreword
The text of ISO 18453:2004 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 18453:2005 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 May 2006, and conflicting national standards
shall be withdrawn at the latest by May 2006.
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 18453:2004 has been approved by CEN as EN ISO 18453:2005 without any
modifications.
INTERNATIONAL ISO
STANDARD 18453
First edition
2004-07-01
Natural gas — Correlation between water
content and water dew point
Gaz naturel — Corrélation entre la teneur en eau et le point de rosée
de l'eau
Reference number
ISO 18453:2004(E)
©
ISO 2004
ISO 18453:2004(E)
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ii © ISO 2004 – All rights reserved
ISO 18453:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Terms and definitions. 1
3 Development of the correlation . 2
4 Range of application and uncertainty of the correlation . 3
5 Correlation . 4
Annex A (normative) Thermodynamic principles . 8
Annex B (informative) Traceability . 15
Annex C (informative) Examples of calculations . 17
Annex D (informative) Subscripts, symbols, units, conversion factors and abbreviations . 19
Bibliography . 21
ISO 18453:2004(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18453 was prepared by Technical Committee ISO/TC 193, Natural gas, Subcommittee SC 1, Analysis of
natural gas.
iv © ISO 2004 – All rights reserved
ISO 18453:2004(E)
Introduction
ISO/TC 193, Natural gas, was established in May 1989, with the task of creating new standards, and updating
existing standards relevant to natural gas. This includes gas analysis, direct measurement of properties,
quality designation and traceability.
This document provides a reliable mathematical relationship between water content and water dew point in
natural gas. The calculation method was developed by GERG; it is applicable in both ways, i.e. either to
calculate the water content or to calculate the water dew point. Information relating to the thermodynamic
principles is given in Annex A; information relating to the traceability, applications and uncertainties associated
with this work is given in Annex B.
Some of the operational problems in the natural gas industry can be traced back to water content in natural
gases. Even with low water vapour content in the gas, changing operating pressure and temperature
conditions can cause water to condense and thus lead to corrosion problems, hydrates or ice formation. To
avoid these problems, expensive dehydration units have been installed by natural gas companies. The design
and cost of these installations depend on the exact knowledge of the water content at the dew point and the
(contractually) required water content.
The instruments resulting from the improvements of moisture measurement equipment during the last
decades focus on the determination of water content rather than on water dew point. Therefore, if the water
content is measured, a correlation is needed for the expression of water dew point.
1)
The GERG Group identified a need to build a comprehensive and accurate database of measured water
content and corresponding water dew point values for a number of representative natural gases in the range
of interest before validating the existing correlations between water content and water dew point.
It was subsequently shown that the uncertainty range of the existing correlations could be improved.
Therefore, as a result, a more accurate, composition-dependent correlation was successfully developed on
the basis of the new database.
The aim of this International Standard is to standardize the calculation procedure developed by GERG
concerning the relationship between water content and water dew point (and vice versa) in the field of natural
gas typically for custody transfer.
1) GERG is an abbreviation of Groupe Européen de Recherche Gazière.
INTERNATIONAL STANDARD ISO 18453:2004(E)
Natural gas — Correlation between water content and water
dew point
1 Scope
This International Standard specifies a method to provide users with a reliable mathematical relationship
between water content and water dew point in natural gas when one of the two is known. The calculation
method, developed by GERG; is applicable to both the calculation of the water content and the water dew
point.
This International Standard gives the uncertainty for the correlation but makes no attempt to quantify the
measurement uncertainties.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
correlation
relationship between two or several random variables within a distribution of two or more random variables
[ISO 3534-1]
NOTE The indication of the range of temperature, pressure and composition for which the correlation was validated
is given in Clause 3.
2.2
working range
range of parameters for which the correlation has been validated
2.3
extended working range
range of parameters for which the correlation has been developed, but outside the range for which the
correlation has been validated
2.4
uncertainty of the correlation
absolute deviation of calculated value from the experimental database
NOTE This does not include any measurement uncertainty in the field.
2.5
acentric factor
parameter to characterize the acentricity or non-sphericity of a molecule
NOTE This definition was taken from reference [1] in the Bibliography.
ISO 18453:2004(E)
2.6
normal reference conditions
reference conditions of pressure, temperature and humidity (state of saturation) equal to 101,325 kPa and
273,15 K for the real, dry gas
[ISO 14532:2001]
2.6
traceability
property of the result of a measurement or the value of a standard whereby it can be related to stated
references, usually national or international standards, through an unbroken chain of comparisons all having
stated uncertainties
[ISO 14532:2001]
3 Development of the correlation
In the past, GERG has identified the necessity for an accurate conversion between the water content and the
water dew point for natural gases with sales gas characteristics. To achieve this goal, the GERG defined a
research program. In the first phase of the project, reliable data on water content together with data on water
dew point were collected for several natural gases for the dew-point temperature range of interest: −15 °C to
+5 °C and for the (absolute) pressure range of interest: 0,5 MPa to 10 MPa. In addition to the measurements
on the seven representative natural gases, measurements were also carried out on the key binary system
methane/water. The procedure used for gathering the measured data was the saturation method.
Taking the determined values for the repeatability and reproducibility of the Karl Fischer instrument as
consistency criteria for all measured water contents, only a few inconsistent valu
...
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