ISO/TR 14749:2016
(Main)Natural gas — Online gas chromatograph for upstream area
Natural gas — Online gas chromatograph for upstream area
ISO/TS 14749:2016 concerns the determination of hydrocarbon components up to C7+ in natural gas in upstream petroleum industry, which describes the principle of operation of GC and provides guidelines for selection, evaluation, and factors impacting upon its performance such as sample probe, sample conditioning, installation, operation and troubleshooting.
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TECHNICAL ISO/TR
REPORT 14749
First edition
2016-05-15
Natural gas — Online gas
chromatograph for upstream area
Gaz naturels — Chromatographe en phase gazeuse en ligne pour
zone amont
Reference number
ISO/TR 14749:2016(E)
©
ISO 2016
---------------------- Page: 1 ----------------------
ISO/TR 14749:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 14749:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Principle of measurement . 1
2.1 General . 1
2.2 Gas composition . 1
3 Sampling and conditioning . 3
4 Online gas chromatograph selection guideline . 6
5 Calibration guidelines . 7
5.1 Calibration procedure . 7
5.1.1 General. 7
5.1.2 Calibration . 7
5.1.3 Calibration frequency . 7
5.2 Calibration gases . 8
5.3 Chromatogram verification . 8
5.3.1 Response Factor (RF) . 8
5.3.2 Retention Time (RT) . 8
6 Verification procedure . 8
6.1 General . 8
6.2 Visual inspection of Sample system . 9
6.3 Visual inspection of analyser . 9
6.4 Carrier Gas . 9
6.5 Calibration Gas . 9
6.6 GC verification . 9
7 Maintenance and Corrective maintenance .10
7.1 Preventive maintenance .10
7.2 Corrective maintenance .10
8 Alarm and diagnostic .10
9 Repeatability and Reproducibility .12
9.1 Repeatability .12
9.2 Reproducibility .12
10 Data handling during GC failure .12
11 Quality Control of analysis data .13
Annex A (informative) Example, comparison between duty and backup GC .14
Annex B (informative) Example, Typical chromatogram .16
Annex C (informative) Example: Analysis result .18
Bibliography .19
© ISO 2016 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TR 14749:2016(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 193, Natural gas, Subcommittee SC 3,
Upstream area.
iv © ISO 2016 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 14749:2016(E)
Introduction
Online Gas Chromatograph (GC) is widely used to determine hydrocarbon components in natural gas
because of its “Real time” measurement and ease of use. It has become a powerful tool for both custody
transfer and upstream process gas monitoring. Especially for the custody transfer which the calorific
value and others gas properties such as, relative density, compressibility factor, etc. are needed for
energy determination. Therefore, accuracy and reliability of the equipment are crucial.
With proper maintenance and handling, GC can provide an accurate result with a minimum manpower
as it analyzes and provides results continuously. With technology today, the unit can do auto-calibration,
alarm setting, diagnostic, troubleshooting and configuring through Human Machine Interface (HMI).
Its outputs can be linked directly with Flow computer, Distributed Control System (DCS) or any remote
personal computer (PC).
The Natural Gas in upstream petroleum industry is normally wet. Then this Technical Report provides
recommended application to handling GC focus on design, selection, operation, maintenance and
verification of GC and its peripheral. The purpose is to provide the whole process to proper handling
the GC until getting the accurate and reliable results. It is also included the sampling system to get the
representative sample, data verification, alarm, diagnostic and troubleshooting including how to deal
with the data in case of being used for custody transfer purpose. Some acceptance criteria are also
identified in this paper based on our historical record and performance of the equipment.
© ISO 2016 – All rights reserved v
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 14749:2016(E)
Natural gas — Online gas chromatograph for upstream area
1 Scope
This Technical Report concerns the determination of hydrocarbon components up to C7+ in natural
gas in upstream petroleum industry, which describes the principle of operation of GC and provides
guidelines for selection, evaluation, and factors impacting upon its performance such as sample probe,
sample conditioning, installation, operation and troubleshooting.
2 Principle of measurement
2.1 General
The GC is a technique for separating and analysing compounds that can be vaporized without
decomposition in a continuous and automatic manner of sample injection, separation, data integration
and reporting. A precise volume of sample gas is injected into the column which contains a stationary
phase (packing) that is either an active solid (adsorption partition) or an inert solid support that is
coated with a liquid phase (absorption partitioning). The gas is moved through the column by means
of a mobile phase (carrier gas). Selective retention of the components of the sample takes place in
the column and causes each component to move through the column at a different rate. This action
separates the sample into its gaseous constituents.
A detector detects the elution of component from the column and produces electrical outputs
proportional to the concentration of each component. Output from the detector are amplified in the
electronics, then transmitted to the controller for further processing.
2.2 Gas composition
Natural gas is composed primarily of methane with smaller amounts of higher hydrocarbons and of
non combustible gases. Major, minor and trace components are as indicated in Tables 1, 2 and 3:
Table 1 — Major components
Component Units
Methane mole %
Ethane mole %
Propane mole %
Butanes mole %
Pentanes mole %
Hexanes mole %
Heptanes plus mole %
Nitrogen mole %
Carbon dioxide mole %
© ISO 2016 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/TR 14749:2016(E)
Table 2 — Minor component
Component Units
Hydrogen mole %
Oxygen mole %
Carbon monoxide mole %
Helium mole %
Table 3 — Trace component
Component Units
3
Hydrogen sulfide mg/m
3
Mercaptan sulfur mg/m
3
Dialkyl (di) sulfide mg/m
3
Carbonyl sulfide mg/m
3
Total sulfur mg/m
Figure 1 — Online Gas Chromatograph Functional Block Diagram
2 © ISO 2016 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 14749:2016(E)
Figure 2 — Online Gas Chromatograph Equipment Diagram
Output from the controller is normally linked to flow computer, DCS, remote personal computer (PC) or
a printer. Connection between the GC Controller and others can be accomplished via a direct serial link
or Ethernet link.
The GC today has features to report alarm and ignore any fault (report last good value) and also
provides good diagnostic and troubleshooting data. To verify the GC performance, repeatability check
with Standard gas and baseline check are recommended.
3 Sampling and conditioning
The nature of gas processing in upstream petroleum industry is relied on gas separation and gas
dehydration units. There is potential of small liquid droplets in Natural Gas which are able to get into
GC causing lots of problems such as incorrect data, failure of GC, etc.
Sample probes and sample conditioning unit have to be properly designed and installed to address
liquid carry over and condensing issues. A well designed, installed and maintained sampling system is
vital to ensure the provision of a representative sample for GC analysis.
The purpose of the sample handling system is not to transfer an exact sample of the process fluid to the
GC. Rather, the purpose is to transfer a representative sample of the fluid after it has been conditioned
that is compatible with GC sample requirements.
The sampling system consists of sample probes, pressure regulators and sample line.
The sample probe design should take into account the possibility of resonant vibration being induced
by high flow velocities in the pipeline. The probe construction can be either a straight tube probe
or a regulated probe. An extraction probe should be considered for maintenance purpose without
depressurizing shutdown.
Referring to ISO 10715, sample probe should be located directly in the gas stream in such a way that
problems induced by aerosols and dust are eliminated. It is recommended that the probe be located
a minimum of 20 pipe diameters downstream from any flow-disturbing elements such as elbows,
© ISO 2016 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/TR 14749:2016(E)
headers, valves and tees. However, due to retriction in the upstream petroleum industry, a distance of
at least 5 pipe diameters downstream of custody metering is accepted.
The location of the probe should be on the top of a horizontal part of the pipe. The sample probe tip
insertion should be located between one-third and centre of the pipeline diameter.
The sampling pressure, especially in upstream petroleum industry is relatively high (more than
4,137 kPa, or 600 psi) but the GC inlet pressure is designed at very low level (less than 138 kPa, or
20 psi), then pressure reduction is relatively important to prevent the liquid into GC. Two different
methods are considered:
— Regulated probe with pressure regulator.
— Heated pressure regulator.
The sample should be heated before reducing the pressure and the regulated probe should be equipped
with fin in order to reduce liquid droplet from Joule-Thomson effect.
Sampling accessories such as aerosol and/or dust trap, coalescer filter are considered to ensure that
liquid droplets are eliminated. The maintenance on the liquid eliminating system should be performed
as frequently as practically possible.
The sampling line should be short and have a small diameter to shorten residence time. A bypass or
fast-loop line should be considered to reduce residence time. The sampling vent should comply with
hazardous area classification.
Whenever ambient temperature is below the hydrocarbon dew point of the stream, heat tracing on the
sample line should be used to keep the sample line temperature 10 °C above the gas dew point. This is
in order to avoid condensation problems and to provide a representative sample to the GC. The heat
tracing should be either electric or steam, however the electrical parts should comply with hazardous
area classification.
NOTE Typically any stream over about 38.73MJ/SCM, or 1 040 btu/scf, will need heat tracing and insulation.
If neccessary a pressure safety relief valve can be installed downstream of the pressure reducer in
order to protect the GC from pressure regulator failure.
Materials being used in sampling are dependent on gas composition, in most cases stainless steel is
recommended, however in some areas where high amount of H2S are present (more than 50ppm) the
duplex stainless steel tubing should be considered. Seats and seals should be made of (elastic) material
appropriate for the intended service.
4 © ISO 2016 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/TR 14749:2016(E)
Figure 3 — Online Gas Chromatograph Sampling System Components
A Sample Conditioning System (SCS) is located between the process stream and the analyser inlet. The
standard configuration SCS should be as represented in Figure 4.
© ISO 2016 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO/TR 14749:2016(E)
Key
V-1 inlet valve (sample in)
V-2 outlet valve (sample to GC)
V-3 outlet valve (bypass)
PRV-1 pressure reducing valve
PSV-1 pressure safety valve
F-1 dust filter
F-2 membrane filter
FI-1 flow indicator
Figure 4 — Online Gas Chromatograph Sample Conditioning System (typical)
4 Online gas chromatograph selection guideline
The GC selection guideline is described below.
— Gas composition: number of gas components of interest as agreed with concerned parties. The
typical available analyzers can analyse hydrocarbon up to C6+ and C7+.
— Analysis method: any system providing adequate peak separation and analytical performance
should be accepted, typical detectors used are TCD, FID and FPD. In case the trace level (ppm order
of magnitude) specific equipment may be considered.
— Electrical equipment should comply with hazardous area classification.
— Instrument system should be equipped with
— Temperature controller should be monitored and adjustable.
— Column with tag to indicate the column information (material, length). The column should be
capable of separating each gas component completely.
6 © ISO 2016 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/TR 14749:2016(E)
— Carrier gas should be equipped with pressure switch to shut off the analyser when pressure is
too low.
— Controller should
— Be equipped with HMI display.
— Have a diagnostic program connected to controller.
— Have the output signal which can be either an analog communication via serial data or
ethernet data.
— Provide chromatograp
...
TECHNICAL ISO/TR
REPORT 14749
First edition
Natural gas — Online gas
chromatograph for upstream area
Gaz naturels — Chromatographe en phase gazeuse en ligne pour
zone amont
PROOF/ÉPREUVE
Reference number
ISO/TR 14749:2016(E)
©
ISO 2016
---------------------- Page: 1 ----------------------
ISO/TR 14749:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TR 14749:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Principle of measurement . 1
2.1 General . 1
2.2 Gas composition . 1
3 Sampling and conditioning . 3
4 Online gas chromatograph selection guideline . 6
5 Calibration guidelines . 7
5.1 Calibration procedure . 7
5.1.1 General. 7
5.1.2 Calibration . 7
5.1.3 Calibration frequency . 7
5.2 Calibration gases . 8
5.3 Chromatogram verification . 8
5.3.1 Response Factor (RF) . 8
5.3.2 Retention Time (RT) . 8
6 Verification procedure . 8
6.1 General . 8
6.2 Visual inspection of Sample system . 9
6.3 Visual inspection of analyser . 9
6.4 Carrier Gas . 9
6.5 Calibration Gas . 9
6.6 GC verification . 9
7 Maintenance and Corrective maintenance .10
7.1 Preventive maintenance .10
7.2 Corrective maintenance .10
8 Alarm and diagnostic .10
9 Repeatability and Reproducibility .12
9.1 Repeatability .12
9.2 Reproducibility .12
10 Data handling during GC failure .12
11 Quality Control of analysis data .13
Annex A (informative) Example, comparison between duty and backup GC .14
Annex B (informative) Example, Typical chromatogram .16
Annex C (informative) Example: Analysis result .19
Bibliography .20
© ISO 2016 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO/TR 14749:2016(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 193, Natural gas, Subcommittee SC 3,
Upstream area.
iv PROOF/ÉPREUVE © ISO 2016 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TR 14749:2016(E)
Introduction
Online Gas Chromatograph (GC) is widely used to determine hydrocarbon components in natural gas
because of its “Real time” measurement and ease of use. It has become a powerful tool for both custody
transfer and upstream process gas monitoring. Especially for the custody transfer which the calorific
value and others gas properties such as, relative density, compressibility factor, etc. are needed for
energy determination. Therefore, accuracy and reliability of the equipment are crucial.
With proper maintenance and handling, GC can provide an accurate result with a minimum manpower
as it analyzes and provides results continuously. With technology today, the unit can do auto-calibration,
alarm setting, diagnostic, troubleshooting and configuring through Human Machine Interface (HMI).
Its outputs can be linked directly with Flow computer, Distributed Control System (DCS) or any remote
personal computer (PC).
The Natural Gas in upstream petroleum industry is normally wet. Then this Technical Report provides
recommended application to handling GC focus on design, selection, operation, maintenance and
verification of GC and its peripheral. The purpose is to provide the whole process to proper handling
the GC until getting the accurate and reliable results. It is also included the sampling system to get the
representative sample, data verification, alarm, diagnostic and troubleshooting including how to deal
with the data in case of being used for custody transfer purpose. Some acceptance criteria are also
identified in this paper based on our historical record and performance of the equipment.
© ISO 2016 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
TECHNICAL REPORT ISO/TR 14749:2016(E)
Natural gas — Online gas chromatograph for upstream area
1 Scope
This Technical Report concerns the determination of hydrocarbon components up to C7+ in natural
gas in upstream petroleum industry, which describes the principle of operation of GC and provides
guidelines for selection, evaluation, and factors impacting upon its performance such as sample probe,
sample conditioning, installation, operation and troubleshooting.
2 Principle of measurement
2.1 General
The GC is a technique for separating and analysing compounds that can be vaporized without
decomposition in a continuous and automatic manner of sample injection, separation, data integration
and reporting. A precise volume of sample gas is injected into the column which contains a stationary
phase (packing) that is either an active solid (adsorption partition) or an inert solid support that is
coated with a liquid phase (absorption partitioning). The gas is moved through the column by means
of a mobile phase (carrier gas). Selective retention of the components of the sample takes place in
the column and causes each component to move through the column at a different rate. This action
separates the sample into its gaseous constituents.
A detector detects the elution of component from the column and produces electrical outputs
proportional to the concentration of each component. Output from the detector are amplified in the
electronics, then transmitted to the controller for further processing.
2.2 Gas composition
Natural gas is composed primarily of methane with smaller amounts of higher hydrocarbons and of
non combustible gases. Major, minor and trace components are as indicated in Tables 1, 2 and 3:
Table 1 — Major components
Component Units
Methane mole %
Ethane mole %
Propane mole %
Butanes mole %
Pentanes mole %
Hexanes mole %
Heptanes plus mole %
Nitrogen mole %
Carbon dioxide mole %
© ISO 2016 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 6 ----------------------
ISO/TR 14749:2016(E)
Table 2 — Minor component
Component Units
Hydrogen mole %
Oxygen mole %
Carbon monoxide mole %
Helium mole %
Table 3 — Trace component
Component Units
3
Hydrogen sulfide mg/m
3
Mercaptan sulfur mg/m
3
Dialkyl (di) sulfide mg/m
3
Carbonyl sulfide mg/m
3
Total sulfur mg/m
Figure 1 — Online Gas Chromatograph Functional Block Diagram
2 PROOF/ÉPREUVE © ISO 2016 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TR 14749:2016(E)
Figure 2 — Online Gas Chromatograph Functional Block Diagram
Output from the controller is normally linked to flow computer, DCS, remote personal computer (PC) or
a printer. Connection between the GC Controller and others can be accomplished via a direct serial link
or Ethernet link.
The GC today has features to report alarm and ignore any fault (report last good value) and also
provides good diagnostic and troubleshooting data. To verify the GC performance, repeatability check
with Standard gas and baseline check are recommended.
3 Sampling and conditioning
The nature of gas processing in upstream petroleum industry is relied on gas separation and gas
dehydration units. There is potential of small liquid droplets in Natural Gas which are able to get into
GC causing lots of problems such as incorrect data, failure of GC, etc.
Sample probes and sample conditioning unit have to be properly designed and installed to address
liquid carry over and condensing issues. A well designed, installed and maintained sampling system is
vital to ensure the provision of a representative sample for GC analysis.
The purpose of the sample handling system is not to transfer an exact sample of the process fluid to the
GC. Rather, the purpose is to transfer a representative sample of the fluid after it has been conditioned
that is compatible with GC sample requirements.
The sampling system consists of sample probes, pressure regulators and sample line.
The sample probe design should take into account the possibility of resonant vibration being induced
by high flow velocities in the pipeline. The probe construction can be either a straight tube probe
or a regulated probe. An extraction probe should be considered for maintenance purpose without
depressurizing shutdown.
Referring to ISO 10715, sample probe should be located directly in the gas stream in such a way that
problems induced by aerosols and dust are eliminated. It is recommended that the probe be located
a minimum of 20 pipe diameters downstream from any flow-disturbing elements such as elbows,
© ISO 2016 – All rights reserved PROOF/ÉPREUVE 3
---------------------- Page: 8 ----------------------
ISO/TR 14749:2016(E)
headers, valves and tees. However, due to retriction in the upstream petroleum industry, a distance of
at least 5 pipe diameters downstream of custody metering is accepted.
The location of the probe should be on the top of a horizontal part of the pipe. The sample probe tip
insertion should be located between one-third and centre of the pipeline diameter.
The sampling pressure, especially in upstream petroleum industry is relatively high (more than
4,137 kPa, or 600 psi) but the GC inlet pressure is designed at very low level (less than 138 kPa, or
20 psi), then pressure reduction is relatively important to prevent the liquid into GC. Two different
methods are considered:
— Regulated probe with pressure regulator.
— Heated pressure regulator.
The sample should be heated before reducing the pressure and the regulated probe should be equipped
with fin in order to reduce liquid droplet from Peng-Robinson effect.
Sampling accessories such as aerosol and/or dust trap, coalescer filter are considered to ensure that
liquid droplets are eliminated. The maintenance on the liquid eliminating system should be performed
as frequently as practically possible.
The sampling line should be short and have a small diameter to shorten residence time. A bypass or
fast-loop line should be considered to reduce residence time. The sampling vent should comply with
hazardous area classification.
Whenever ambient temperature is below the hydrocarbon dew point of the stream, heat tracing on the
sample line should be used to keep the sample line temperature 10 °C above the gas dew point. This is
in order to avoid condensation problems and to provide a representative sample to the GC. The heat
tracing should be either electric or steam, however the electrical parts should comply with hazardous
area classification.
NOTE Typically any stream over about 38.73MJ/SCM, or 1 040 btu/scf, will need heat tracing and insulation.
If neccessary a pressure safety relief valve can be installed downstream of the pressure reducer in
order to protect the GC from pressure regulator failure.
Materials being used in sampling are dependent on gas composition, in most cases stainless steel is
recommended, however in some areas where high amount of H2S are present (more than 50ppm) the
duplex stainless steel tubing should be considered. Seats and seals should be made of (elastic) material
appropriate for the intended service.
4 PROOF/ÉPREUVE © ISO 2016 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/TR 14749:2016(E)
Figure 3 — Online Gas Chromatograph Functional Block Diagram
A Sample Conditioning System (SCS) is located between the process stream and the analyser inlet. The
standard configuration SCS should be as represented in Figure 4.
© ISO 2016 – All rights reserved PROOF/ÉPREUVE 5
---------------------- Page: 10 ----------------------
ISO/TR 14749:2016(E)
Key
V-1 inlet valve (sample in)
V-2 outlet valve (sample to GC)
V-3 outlet valve (bypass)
PRV-1 pressure reducing valve
PSV-1 pressure safety valve
F-1 dust filter
F-2 membrane filter
FI-1 flow indicator
Figure 4 — Online Gas Chromatograph Sample Conditioning System (typical)
4 Online gas chromatograph selection guideline
The GC selection guideline is described below.
— Gas composition: number of gas components of interest as agreed with concerned parties. The
typical available analyzers can analyse hydrocarbon up to C6+ and C7+.
— Analysis method: any system providing adequate peak separation and analytical performance
should be accepted, typical detectors used are TCD, FID and FPD. In case the trace level (ppm order
of magnitude) specific equipment may be considered.
— Electrical equipment should comply with hazardous area classification.
— Instrument system should be equipped with
— Temperature controller should be monitored and adjustable.
— Column with tag to indicate the column information (material, length). The column should be
capable of separating each gas component completely.
6 PROOF/ÉPREUVE © ISO 2016 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/TR 14749:2016(E)
— Carrier gas should be equipped with pressure switch to shut off the analyser when pressure is
too low.
— Controller should
— Be equipped with HMI display.
— Have a diagnostic program connected to controller.
— Have the output signal which can be either an analog communication via serial data or
ethernet data.
— Provide chromatograph of calibration and analysis.
— Keep calibration and analysis result.
— Keep alarm and event l
...
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