ASTM D7165-22

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7165 − 10 (Reapproved 2015) D7165 − 22
Standard Practice for
Gas Chromatograph Based On-line/At-line Analysis for
Sulfur Content of Gaseous Fuels
This standard is issued under the fixed designation D7165; 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
1.1 This practice is for the determination of volatile gas phase sulfur-containing compounds in high methane content gaseous fuels
such as natural gas using on-line/at-line instrumentation, and continuous fuel monitors (CFMS). It has been successfully applied
to other types of gaseous samples including air, digester, landfill, and refinery fuel gas. The detection range for sulfur compounds,
reported as picograms sulfur, based upon the analysis of a 1 cc 1 mL sample, is one hundred (100) to one million
(1,000,000).(1 000 000). This is equivalent to 0.1 to 1,000 mg/m3.1000 mg/m .
1.2 This practice does not purport to measure all sulfur species in a sample. Only volatile gas phase compounds that are
transported to an instrument under the measurement conditions selected are measured.
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.4 This practicestandard 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 practicestandard to establish appropriate safety safety, health, and healthenvironmental practices
and determine the applicability of regulatory limitations prior to use.
1.5 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
2.1 ASTM Standards:
D1072 Test Method for Total Sulfur in Fuel Gases by Combustion and Barium Chloride Titration
D1945 Test Method for Analysis of Natural Gas by Gas Chromatography
D3606D3609 Test Method for Determination of Benzene and Toluene in Spark Ignition Fuels by Gas ChromatographyPractice
for Calibration Techniques Using Permeation Tubes
D3764 Practice for Validation of the Performance of Process Stream Analyzer Systems
D4084 Test Method for Analysis of Hydrogen Sulfide in Gaseous Fuels (Lead Acetate Reaction Rate Method)
D4150 Terminology Relating to Gaseous Fuels
D4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Colorimetry
This practice is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line Analysis
of Gaseous Fuels.
Current edition approved June 1, 2015Nov. 1, 2022. Published July 2015November 2022. Originally approved in 2006. Last previous edition approved in 20102015 as
D7165D7165 – 10–10.(2015). DOI: 10.1520/D7165-10R15.10.1520/D7165-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7165 − 22
D4626 Practice for Calculation of Gas Chromatographic Response Factors
D4810 Test Method for Hydrogen Sulfide in Natural Gas Using Length-of-Stain Detector Tubes
D5504 Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and
Chemiluminescence
D6621 Practice for Performance Testing of Process Analyzers for Aromatic Hydrocarbon Materials
D6122 Practice for Validation of the Performance of Multivariate Online, At-Line, Field and Laboratory Infrared
Spectrophotometer, and Raman Spectrometer Based Analyzer Systems
D6228 Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and
Flame Photometric Detection
D7493 Test Method for Online Measurement of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatograph
and Electrochemical Detection
D7551 Test Method for Determination of Total Volatile Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum Gases and
Natural Gas by Ultraviolet Fluorescence
D7833 Test Method for Determination of Hydrocarbons and Non-Hydrocarbon Gases in Gaseous Mixtures by Gas
Chromatography
E594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
2.2 ISO StandardsStandards:
ISO 7504 Gas Analysis-Vocabulary
3. Terminology
3.1 For definitions of general terms used in D03 Gaseous Fuels standards, refer to Terminology D4150.
3.2 Definitions:Definitions of Terms Specific to This Standard:
3.1.1 calibration gas mixture, n—a certified gas mixture with known composition used for the calibration of a measuring
instrument or for the validation of a measurement or gas analytical method.
3.1.1.1 Discussion—
Calibration Gas Mixtures are the analogues of measurement standards in physical metrology (reference ISO 7504 paragraph 4.1).
3.1.2 direct sampling—Sampling where there is no direct connection between the medium to be sampled and the analytical unit.
3.1.3 in-line instrument—Instrument whose active element is installed in the pipeline and measures at pipeline conditions.
3.1.4 on-line instrument—Automated instrument that samples gas directly from the pipeline, but is installed externally.
3.1.5 at-line instrument—instrument requiring operator interaction to sample gas directly from the pipeline.
3.1.6 continuous fuel monitor (CFM)—Instrument that samples gas directly from the pipeline on a continuous or semi-continuous
basis.
3.1.7 total reduced sulfur (TRS)—Summation of sulfur species where the sulfur oxidation number is –2, excluding sulfur dioxide,
sulfones, and other inorganic sulfur compounds. This includes but is not limited to mercaptans, sulfides, and disulfides.
3.2.1 near-real time monitoring systems—systems, n—Monitoringmonitoring system where measurement occurs soon after sample
flow through the system or soon after sample extraction. The definition of a near real time monitoring system can be application
specific.
3.2.1.1 Discussion—
The definition of a near real time monitoring system can be application specific.
3.2 reference gas mixture, n—a certified gas mixture with known composition used as a reference standard from which other
compositional data are derived.
3.2.1 Discussion—
Reference Gas Mixtures are the analogues of measurement standards of reference standards (reference ISO 7504 paragraph 4.1.1).
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.
D7165 − 22
3.3 Abbreviations:
3.3.1 CFM—continuous fuel monitor
3.3.2 SRM—standard reference material
4. Summary of Practice
4.1 A representative sample of the gaseous fuel is extracted from a process pipe or pipeline and is transferred in a timely manner
to an analyzer inlet system. The sample is conditioned with minimum impact on sulfur content. A precisely measured volume of
sample is injected into the analyzer. Excess process or pipeline sample is vented or is returned to the process stream dependant
upon application and regulatory requirements.
4.2 Sample containing carrier gas is fed to a gas chromatograph where the components are separated using either a packed or
capillary column. Measurement is performed using a suitable sulfur detection system.
4.3 Calibration, precision, calibration error, performance audit tests, maintenance methodology and miscellaneous quality
assurance procedures are conducted to determine analyzer performance characteristics and validate both the operation and the
quality of generated results.
5. Significance and Use
5.1 On-line, at-line, in-line, CFMS, and other near-real time monitoring systems that measure fuel gas characteristics, such as the
sulfur content, are prevalent in the natural gas and fuel gas industries. The installation and operation of particular systems vary on
the specific objectives, contractual obligations, process type, regulatory requirements, and internal performance requirements
needed by the user. This standard is intended to provide guidelines for standardized start-up procedures, operating procedures, and
quality assurance practices for on-line, at-line, in-line, CFMS, and other near-real time gas chromatographic based sulfur
monitoring systems used to determine fuel gas sulfur content. For measurement of gaseous fuel properties using laboratory based
methods, the user is referred to Test Methods D1072, D1945, D4084, D4468, D4810, D7833, and Practices D4626, E594.
6. Apparatus
6.1 Instrument—Any gas chromatographic based instrument of standard manufacture, with hardware necessary for interfacing to
a natural gas or other fuel gas pipeline and containing all features necessary for the intended application(s) can be used.
6.1.1 The chromatographic parameters must be capable of obtaining retention time repeatability of 0.05 min. (3 sec.). 0.05 min
(3 s). Instrumentation must meet the performance characteristics for repeatability and precision without encountering unacceptable
interference or bias. The components coming in contact with sample, such as tubing and valving, must be passivated or constructed
of inert materials to ensure an accurate sulfur gas measurement.
6.2 Sample Inlet System—A sample inlet system capable of operating continuously above the maximum column temperature is
necessary. A variety of sample inlet configurations can be used including, but not limited to, on-column systems and split/splitless
injection system capable of splitless operation and split control from 10:1 up to 50:1. An automated gas sampling valve is required
for many applications. The inlet system must be constructed of inert material and evaluated frequently for compatibility with
reactive sulfur compounds. The sampling inlet system is heated as necessary so as to prevent condensation. All wetted sampling
system components must be constructed of inert or passivated materials. Sample delivered to the inlet system should be in the gas
phase free of particulate or fluidic matter.
6.2.1 Carrier and Detector Gas Control—Constant flow control of carrier and detector gases is critical for optimum and consistent
analytical performance. Control is achieved by use of pressure regulators and fixed flow restrictors. The gas flow is measured by
appropriate means and adjusted, as required, to the desired value. Mass flow controllers, capable of maintaining a gas flow constant
to within 6 1 % at the flow rates necessary for optimal instrument performance can be used.
6.2.2 Detector—Sulfur compounds can be measured using a variety of detectors including, but not limited to: sulfur
chemiluminescence, flame photometric, electrochemical cell, oxidative cell and reductive cells. In selecting a detector, the user
D7165 − 22
should consider the linearity, sensitivity, and selectivity of particular detection systems prior to installation. The user should also
consider interference from substances in the gas stream that could result in inaccurate sulfur gas measurement due to effects such
as quenching.
6.3 Columns—A variety of columns can be used to separate the sulfur compounds in the sample. Typically, a 60 m × 0.53 mm
60 m × 0.53 mm ID fused silica open tubular column containing a 5 μm film thickness of bonded methyl silicone liquid phase is
used. The selected column must provide retention and resolution characteristics that satisfy the intended application. The column
must be inert towards sulfur compounds. The column must also demonstrate a sufficiently low liquid phase bleed at high
temperature such that a loss of the instrument response is not encountered while operating the column at elevated temperatures.
6.4 Data Acquisition—Data acquisition and storage can be accomplished using a number of devices and media. Following are
some examples.
6.4.1 Recorder—As an example, a 0 to 1 mV 1 mV range recording potentiometer or equivalent, with a full-scale response time
of 2 s 2 s or less can be used. A 4-20 mA 4-20 mA range recorder can also be used.
6.4.2 Integrator—An electronic integrating device or computer can be used. For GC based systems, it is suggested that the device
and software have the following capabilities:
6.4.2.1 Graphic presentation of chromatograms.
6.4.2.2 Digital display of chromatographic peak areas.
6.4.2.3 Identification of peaks by retention time or relative retention time, or both.
6.4.2.4 Calculation and use of response factors.
6.4.2.5 External standard calculation and data presentation.
6.4.3 Distributed Control Systems (DCS)—Depending on the site requirements, the analytical results are sometimes fed to a
distributed control system. The information is then used to make the appropriate adjustments to the process. Signal isolation
between the analyzer and the distributed control network is most often required. Communications protocols with the DCS will
dictate the required signal output requirements for the analyzer.
6.4.4 Data Management Systems—Data management systems or other data and data processing repositories are sometimes used
to collect and process the results from a wide variety of instrumentation at a single facility. The information is then available for
rapid dissemination within the organization of the operating facility. Communications protocols with the data management system
will dictate the required signal output requirements for the analyzer.
7. Reagents and Materials
NOTE 1—Warning: Sulfur compounds contained in permeation tubes or compressed gas cylinders may be flammable and harmful or fatal if ingested or
inhaled. Permeation tubes, which emit their contents continuously, and compressed gas standards should only be handled in well ventilated locations away
from sparks and flames. Improper handling of compressed gas cylinders containing air, hydrogen, argon, nitrogen, or helium can result in an explosion
or in creating oxygen deficient atmospheres. Rapid release of argon, nitrogen, or helium can result in asphyxiation. Compressed air supports combustion.
7.1 Sulfur Standards—Accurate sulfur standards are required for the quantitation of the sulfur content of natural gas. in natural
gas and other fuel type gases. Permeation and compressed gas standards should be stable, and of the highest available accuracy
and purity.
7.1.1 Permeation Devices—Sulfur standards can be produced on demand using permeation tubes, one for each selected sulfur
species, gravimetrically calibrated and certified at a convenient operating temperature. With constant temperature, calibration gases
covering a wide range of concentration can be generated by varying and accurately measuring the flow rate of diluent gas passing
over the tubes. Permeation devices delivering calibrant at a known high purity must be used since contaminants will adversely
impact the calculation of analyte concentration due to error in permeation rate calculated from differential weight measurements
of these devices. It is suggested that certified permeation devices be used whenever available. Detailed guidance on calibration
using permeation tubes can be found in Practice D3609.
D7165 − 22
7.1.1.1 Permeation System Temperature Control—Permeation devices are maintained at the calibration temperature within 0.1 °C.
0.1 °C.
7.1.1.2 Permeation System Flow Control—The permeation flow system measures diluent gas flow over the permeation tubes
within 62 percent.
7.1.1.3 Permeation tube emission rates are expressed in units of mass of the emitted sulfur compound contained inside per unit
time, i.e. that is, nanograms of methyl mercaptan analyte per minute. The sulfur emission rate is calculated knowing the molecular
formula of the sulfur compound used in the permeation tube.
7.1.1.4 Permeation tubes are inspected and weighed to the nearest 0.01 mg on at least a monthly basis using a balance calibrated
against NIST traceable “S” class weights or the equivalent. Analyte concentration is calculated by weight loss and dilution gas flow
rate as per Practice D3606D3609. These devices are discarded when the liquid contents are reduced to less than ten (10) percent
of the initial volume or when the permeation surface is unusually discolored or otherwise compromised.
7.1.1.5 Permeation tubes must be stored in accordance with the manufacturer’s recommendation. Improper storage can result in
damage and/oror a change in the characteristics of the permeation membrane. membrane, or both. Such damage and/or
characteristic change or characteristic change, or both, results in an actual permeation rate that differs from the certified permeation
rate.
7.2 Compressed Gas Standards—Alternatively, blended gaseous sulfur standards in nitrogen, helium, or methane base gas may be
used. Care must be exercised in the use of compressed gas standards since they can introduce errors in measurement due to lack
of uniformity in their manufacture or instability in their storage and use. Standards should be blended such that components will
not condense under storage or while the standard is in use. The protocol for compressed gas standards contained in the appendix
can be used to ensure uniformity in compressed gas standard manufacture and provide for traceability to a NIST or NMi
(N
...