ASTM D7166-10(2015)
(Practice)Standard Practice for Total Sulfur Analyzer Based On-line/At-line for Sulfur Content of Gaseous Fuels
Standard Practice for Total Sulfur Analyzer Based On-line/At-line for Sulfur Content of Gaseous Fuels
SIGNIFICANCE AND USE
5.1 On-line, at-line, in-line and other near-real time monitoring systems that measure fuel gas characteristics such as the total 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 protocol is intended to provide guidelines for standardized start-up procedures, operating procedures, and quality assurance practices for on-line, at-line, in-line and other near-real time total sulfur monitoring systems.
SCOPE
1.1 This practice is for the determination of total sulfur from volatile sulfur-containing compounds in high methane or hydrogen content gaseous fuels using on-line/at-line instrumentation.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Designation: D7166 − 10 (Reapproved 2015)
Standard Practice for
Total Sulfur Analyzer Based On-line/At-line for Sulfur
Content of Gaseous Fuels
This standard is issued under the fixed designation D7166; 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 Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
D5503 Practice for Natural Gas Sample-Handling and Con-
1.1 This practice is for the determination of total sulfur from
ditioning Systems for Pipeline Instrumentation
volatile sulfur-containing compounds in high methane or
D5504 Test Method for Determination of Sulfur Compounds
hydrogen content gaseous fuels using on-line/at-line instru-
in Natural Gas and Gaseous Fuels by Gas Chromatogra-
mentation.
phy and Chemiluminescence
1.2 The values stated in SI units are to be regarded as
D6122 Practice for Validation of the Performance of Multi-
standard. No other units of measurement are included in this
variate Online, At-Line, and Laboratory Infrared Spectro-
standard.
photometer Based Analyzer Systems
1.3 This standard does not purport to address all of the
D6299 Practice for Applying Statistical Quality Assurance
safety concerns, if any, associated with its use. It is the and Control Charting Techniques to Evaluate Analytical
responsibility of the user of this standard to establish appro-
Measurement System Performance
priate safety and health practices and determine the applica- D6621 Practice for Performance Testing of Process Analyz-
bility of regulatory limitations prior to use.
ers for Aromatic Hydrocarbon Materials
D6667 Test Method for Determination of Total Volatile
2. Referenced Documents
Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum
Gases by Ultraviolet Fluorescence
2.1 ASTM Standards:
D6920 Test Method for Total Sulfur in Naphthas, Distillates,
D1070 Test Methods for Relative Density of Gaseous Fuels
Reformulated Gasolines, Diesels, Biodiesels, and Motor
D1072 Test Method for Total Sulfur in Fuel Gases by
Fuels by Oxidative Combustion and Electrochemical De-
Combustion and Barium Chloride Titration
tection
D3246 Test Method for Sulfur in Petroleum Gas by Oxida-
2.2 ISO Standards
tive Microcoulometry
D3609 Practice for Calibration Techniques Using Perme- ISO 7504 Gas Analysis-Vocabulary
ation Tubes
3. Terminology
D3764 Practice for Validation of the Performance of Process
Stream Analyzer Systems
3.1 Definitions:
D4298 Guide for Intercomparing Permeation Tubes to Es-
3.1.1 at-line instrument—instrumentation requiring operator
tablish Traceability
interaction that samples gas directly from the pipeline.
D4468 Test Method for Total Sulfur in Gaseous Fuels by
3.1.2 calibration gas mixture, n—a certified gas mixture
Hydrogenolysis and Rateometric Colorimetry
with known composition used for the calibration of a measur-
D5287 Practice for Automatic Sampling of Gaseous Fuels
ing instrument or for the validation of a measurement or gas
D5453 Test Method for Determination of Total Sulfur in
analytical method.
Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel
3.1.2.1 Discussion—Calibration Gas Mixtures are the ana-
logues of measurement standards in physical metrology (ref-
erence ISO 7504 paragraph 4.1).
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
3.1.3 continuous fuel monitor—instrument that samples gas
Analysis of Gaseous Fuels.
directly from the pipeline on a continuous or semi-continuous
Current edition approved June 1, 2015. Published July 2015 Originally approved
basis.
in 2005. Last previous edition approved in 2010 as D7166–10. DOI: 10.1520/
D7166-10R15.
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 Available from International Organization for Standardization (ISO), 1, ch. de
Standards volume information, refer to the standard’s Document Summary page on la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://
the ASTM website. www.iso.ch.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7166 − 10 (2015)
3.1.4 direct sampling—sampling where there is no direct vary on the specific objectives, contractual obligations, process
connection between the medium to be sampled and the type, regulatory requirements, and internal performance re-
analytical unit. quirements needed by the user. This protocol is intended to
provide guidelines for standardized start-up procedures, oper-
3.1.5 in-line instrument—instrument with an active element
ating procedures, and quality assurance practices for on-line,
installed in a pipeline, which is used to measure pipeline
at-line, in-line and other near-real time total sulfur monitoring
contents or conditions.
systems.
3.1.6 on-line instrument—instrument that samples gas di-
rectly from a pipeline, but is installed externally.
6. Apparatus
3.1.7 reference gas mixture, n—a certified gas mixture with
6.1 Instrument—Any instrument of standard manufacture,
known composition used as a reference standard from which
with hardware necessary for interfacing to a natural gas,
other compositional data are derived.
hydrogen or other fuel gas pipeline and containing all the
3.1.7.1 Discussion—Reference Gas Mixtures are the ana-
features necessary for the intended application(s) can be used.
logues of measurement standards of reference standards (ref-
6.1.1 Specific Sulfur Specie Detection Systems—The oper-
erence ISO 7504 paragraph 4.1.1).
ating parameters employed generally must be capable of
3.1.8 total reduced sulfur (TRS)—concentration summation
converting all of the volatile sulfur species in the sample into
of all volatile sulfur species with a −2 sulfur oxidation number,
a single detectable species such as sulfur dioxide or hydrogen
excluding sulfur dioxide, sulfones and other inorganic sulfur
sulfide. Instrumentation must satisfy or exceed other analytic
compounds.
performance characteristics for accuracy and precision for the
intended application without encountering unacceptable inter-
3.1.9 total sulfur—concentration summation of all volatile
ference or bias. In addition, components in contact with sample
sulfur species in a sample.
streams such as tubing and valving must be constructed of
3.1.10 volatile—molecular characteristic wherein the sulfur
suitable inert, or passivated, materials to ensure constituents in
specie exists in the gas phase at the operating conditions of the
the fuel stream do not degrade these components or alter the
process or pipeline.
composition of the sampled gas.
4. Summary of Practice
6.2 Sample Probes/Sample Extraction—The location and
orientation of sampling components are critical for ensuring
4.1 A representative sample of the gaseous fuel is extracted
that a representative sample is analyzed. The locations and
from a process pipe or pipeline and is transferred in a timely
orientation of sampling components should be selected based
manner through an appropriately designed sampling system to
upon sound analytic and engineering considerations. Sampling
the inlet of a total sulfur analyzer. The sample is conditioned
practices for gaseous fuels can be found in Practice D5287.
with a minimum, preferably negligible, impact on the sulfur
content. A precisely measured volume of sample is either
6.3 Sample Inlet System—The siting and installation of an
injected, or allowed to flow continuously, either directly into
at-line or on-line monitor is critical for collecting representa-
the analyzer or into a carrier gas, as required by the analyzer.
tive information on sulfur content. Factors that should be
Some total sulfur analyzer systems are configured such that
considered in siting an instrument include ease of calibration,
sample gas flows directly into the analyzer detection system.
ease of access for repair or maintenance, sample uniformity at
Excess process or pipeline sample is vented to atmosphere, to
the sampling point, appropriateness of samples from a sam-
flare or to the process stream dependant upon application and
pling location, ambient conditions, and of course safety issues.
regulatory requirements.
An automated gas sampling valve is required in many appli-
cations. All sampling system components in contact with the
4.2 Sample containing carrier gas is fed to a furnace
fuel stream must be constructed of inert or passivated materi-
operating at an elevated temperature where sulfur compounds
als. Care should be taken to ensure that the extracted sample is
are converted into detectable species. The conversion reaction
maintained as a particulate and condensate free gas. Heating at
may be oxidative or reductive and may require the introduction
the point of pressure reduction or along the sample line to the
of additional carrier or other supply gases.
analyzer and the use of a filter may be required to ensure that
4.3 Furnace exit gasses are conditioned as required with
the sample is maintained in the gas phase. The need for heat
respect to temperature and water content and are introduced
tracing and the extent to which it is required will be site and
into the detector where quantification of the total sulfur content
application specific. In general, considerations impacting heat
occurs.
tracing decisions include sample compositions and the ex-
4.4 Calibration, maintenance, quality assurance and perfor-
pected variations, ambient temperature fluctuations, operating
mance protocols provide a means to validate the analyzer
pressures, anticipated pressure differentials in sample system
operation and the generated results.
components, and safety considerations. Sample filtration
should be utilized as required to remove particulate matter
5. Significance and Use
from the extracted sample. The sampling frequency relative to
5.1 On-line, at-line, in-line and other near-real time moni- the process bandwidth is critical to ensuring that the reported
toring systems that measure fuel gas characteristics such as the analytical results adequately represent the process being moni-
total sulfur content are prevalent in the natural gas and fuel gas tored. The Nyquist-Shannon sampling criterion of a sampling
industries. The installation and operation of particular systems frequency that exceeds twice the process bandwidth can be
D7166 − 10 (2015)
used to establish a minimum analytical cycle time. Sample tration , such as an alarm limit, can be used to identlify the
handling and conditioning system practices can be found in desired total sulfur concentration of the standard. Using a
Practice D5503. sulfur specie that differs from what the detector sees allows for
6.3.1 Carrier and Detector Gas Control—Constant flow a total analyzer system performance check. Standards must be
control of carrier and detector gases is critical for optimum and maintained within the temperature range specified by the
consistent analytical performance. Control is achieved by use manufacturer to ensure accuracy and stability.
of pressure regulators and fixed flow restrictors as well as
7.3 Permeation Devices—Permeation devices contain an
rotameters. Temperature control is generally vital for ensuring
aliquot of a specific compound that continuously diffuses at a
consistent operation of these devices. The gas flow is measured
determined rate through a permeable medium. A dry inert
by appropriate means and adjusted as necessary. Mass flow
carrier gas flows at a constant rate across the medium at a
controllers, capable of maintaining a gas flow constant to
constant temperature consistent with the manufacturer’s rec-
within 61 % at the flow rates necessary for optimal instrument
ommendations to create a calibration gas that then flows to the
performance are typically used.
analyzer. Proper storage, in accordance with the manufactur-
6.3.2 Detectors—Common detectors used for total sulfur
er’s recommendations, is required to prevent damage to the
determinations include chemiluminescence (Test Method
membrane. A sufficiently long equilibration time is required
D5504), microcoulometry (Test Method D3246), electrochemi-
when the permeation device temperature is changed to ensure
cal (Test Method D6920), lead acetate (Test Method D4468),
the reestablishment of a constant permeation rate. Calibration
titration, such as barium chloride (Test Method D1072),
devices using permeation tubes contain a temperature con-
ultra-violet fluorescence (Test Methods D5453 and D6667),
trolled oven and employ flow control to maintain a constant
both continuous and pulsed. Other detectors can be used
diluent flow rate. Practice D3609 and Guide D4298 contain
provided they have appropriate linearity, sensitivity, and selec-
additional information on permeation tubes.
tivity for the selected application. In selecting a detector, the
user should consider the linearity, sensitivity, and selectivity of
8. Equipment Siting and Installation
particular detection systems prior to installation. The user
8.1 A sample inlet system capable of operating continuously
should also consider interference from substances in the gas
and delivering a gas phase sample to the analyzer is necessary.
stream that could result in inaccurate sulfur gas measurement
The location of the sample inlet to the analyzer relative to the
due to effects such as quenching.
sample extraction point is critical to obtaining timely analytical
6.4 Data Acquisition—Data acquisition and storage can be
results. Ideally, the analyzer is close coupled to the sample
accomplished using a number of devices and media. Following
extraction point and there is an insignificant sampling lag time.
are some examples.
Normally, the analyzer is mounted at some distance away from
6.4.1 Recorder—A 0 to 1 mV range recording potentiometer
the sample extraction point. This increased distance represents
or equivalent can be used.
increased lag time between when a sample is extracted from a
6.4.2 Communications—Efficient communications between
process and when an analytical result is reported. The maxi-
the analyzer and the host depend on resolving any and all
mum allowable lag time depends on the specifics of the
interface issues. Signals to and from the host are typically
sampling location relative to the process being sampled. A fast
optically isolated from each other.
loop sweep can be used to minimize the lag time by creating a
b
...
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: D7166 − 10 D7166 − 10 (Reapproved 2015)
Standard Practice for
Total Sulfur Analyzer Based On-line/At-line for Sulfur
Content of Gaseous Fuels
This standard is issued under the fixed designation D7166; 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 total sulfur from volatile sulfur-containing compounds in high methane or hydrogen
content gaseous fuels using on-line/at-line instrumentation.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D1070 Test Methods for Relative Density of Gaseous Fuels
D1072 Test Method for Total Sulfur in Fuel Gases by Combustion and Barium Chloride Titration
D3246 Test Method for Sulfur in Petroleum Gas by Oxidative Microcoulometry
D3609 Practice for Calibration Techniques Using Permeation Tubes
D3764 Practice for Validation of the Performance of Process Stream Analyzer Systems
D4298 Guide for Intercomparing Permeation Tubes to Establish Traceability
D4468 Test Method for Total Sulfur in Gaseous Fuels by Hydrogenolysis and Rateometric Colorimetry
D5287 Practice for Automatic Sampling of Gaseous Fuels
D5453 Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel,
and Engine Oil by Ultraviolet Fluorescence
D5503 Practice for Natural Gas Sample-Handling and Conditioning Systems for Pipeline Instrumentation
D5504 Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and
Chemiluminescence
D6122 Practice for Validation of the Performance of Multivariate Online, At-Line, and Laboratory Infrared Spectrophotometer
Based Analyzer Systems
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6621 Practice for Performance Testing of Process Analyzers for Aromatic Hydrocarbon Materials
D6667 Test Method for Determination of Total Volatile Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum Gases by
Ultraviolet Fluorescence
D6920 Test Method for Total Sulfur in Naphthas, Distillates, Reformulated Gasolines, Diesels, Biodiesels, and Motor Fuels by
Oxidative Combustion and Electrochemical Detection
2.2 ISO Standards
ISO 7504 Gas Analysis-Vocabulary
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 Jan. 1, 2010June 1, 2015. Published February 2010July 2015 Originally approved in 2005. Last previous edition approved in 20052010 as
D7166D7166–05.–10. DOI: 10.1520/D7166-10.10.1520/D7166-10R15.
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.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7166 − 10 (2015)
3. Terminology
3.1 Definitions:
3.1.1 at-line instrument—instrumentation requiring operator interaction that samples gas directly from the pipeline.
3.1.2 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.
3.1.2.1 Discussion—
Calibration Gas Mixtures are the analogues of measurement standards in physical metrology (reference ISO 7504 paragraph 4.1).
3.1.3 continuous fuel monitor—instrument that samples gas directly from the pipeline on a continuous or semi-continuous basis.
3.1.4 direct sampling—sampling where there is no direct connection between the medium to be sampled and the analytical unit.
3.1.5 in-line instrument—instrument with an active element installed in a pipeline, which is used to measure pipeline contents
or conditions.
3.1.6 on-line instrument—instrument that samples gas directly from a pipeline, but is installed externally.
3.1.7 reference gas mixture, n—a certified gas mixture with known composition used as a reference standard from which other
compositional data are derived.
3.1.7.1 Discussion—
Reference Gas Mixtures are the analogues of measurement standards of reference standards (reference ISO 7504 paragraph 4.1.1).
3.1.8 total reduced sulfur (TRS)—concentration summation of all volatile sulfur species with a −2 sulfur oxidation number,
excluding sulfur dioxide, sulfones and other inorganic sulfur compounds.
3.1.9 total sulfur—concentration summation of all volatile sulfur species in a sample.
3.1.10 volatile—molecular characteristic wherein the sulfur specie exists in the gas phase at the operating conditions of the
process or pipeline.
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
through an appropriately designed sampling system to the inlet of a total sulfur analyzer. The sample is conditioned with a
minimum, preferably negligible, impact on the sulfur content. A precisely measured volume of sample is either injected, or allowed
to flow continuously, either directly into the analyzer or into a carrier gas, as required by the analyzer. Some total sulfur analyzer
systems are configured such that sample gas flows directly into the analyzer detection system. Excess process or pipeline sample
is vented to atmosphere, to flare or to the process stream dependant upon application and regulatory requirements.
4.2 Sample containing carrier gas is fed to a furnace operating at an elevated temperature where sulfur compounds are converted
into detectable species. The conversion reaction may be oxidative or reductive and may require the introduction of additional
carrier or other supply gases.
4.3 Furnace exit gasses are conditioned as required with respect to temperature and water content and are introduced into the
detector where quantification of the total sulfur content occurs.
4.4 Calibration, maintenance, quality assurance and performance protocols provide a means to validate the analyzer operation
and the generated results.
5. Significance and Use
5.1 On-line, at-line, in-line and other near-real time monitoring systems that measure fuel gas characteristics such as the total
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 protocol is intended to provide guidelines for standardized start-up procedures, operating procedures, and
quality assurance practices for on-line, at-line, in-line and other near-real time total sulfur monitoring systems.
6. Apparatus
6.1 Instrument—Any instrument of standard manufacture, with hardware necessary for interfacing to a natural gas, hydrogen
or other fuel gas pipeline and containing all the features necessary for the intended application(s) can be used.
6.1.1 Specific Sulfur Specie Detection Systems—The operating parameters employed generally must be capable of converting
all of the volatile sulfur species in the sample into a single detectable species such as sulfur dioxide or hydrogen sulfide.
Instrumentation must satisfy or exceed other analytic performance characteristics for accuracy and precision for the intended
D7166 − 10 (2015)
application without encountering unacceptable interference or bias. In addition, components in contact with sample streams such
as tubing and valving must be constructed of suitable inert, or passivated, materials to ensure constituents in the fuel stream do
not degrade these components or alter the composition of the sampled gas.
6.2 Sample Probes/Sample Extraction—The location and orientation of sampling components are critical for ensuring that a
representative sample is analyzed. The locations and orientation of sampling components should be selected based upon sound
analytic and engineering considerations. Sampling practices for gaseous fuels can be found in Practice D5287.
6.3 Sample Inlet System—The siting and installation of an at-line or on-line monitor is critical for collecting representative
information on sulfur content. Factors that should be considered in siting an instrument include ease of calibration, ease of access
for repair or maintenance, sample uniformity at the sampling point, appropriateness of samples from a sampling location, ambient
conditions, and of course safety issues. An automated gas sampling valve is required in many applications. All sampling system
components in contact with the fuel stream must be constructed of inert or passivated materials. Care should be taken to ensure
that the extracted sample is maintained as a particulate and condensate free gas. Heating at the point of pressure reduction or along
the sample line to the analyzer and the use of a filter may be required to ensure that the sample is maintained in the gas phase.
The need for heat tracing and the extent to which it is required will be site and application specific. In general, considerations
impacting heat tracing decisions include sample compositions and the expected variations, ambient temperature fluctuations,
operating pressures, anticipated pressure differentials in sample system components, and safety considerations. Sample filtration
should be utilized as required to remove particulate matter from the extracted sample. The sampling frequency relative to the
process bandwidth is critical to ensuring that the reported analytical results adequately represent the process being monitored. The
Nyquist-Shannon sampling criterion of a sampling frequency that exceeds twice the process bandwidth can be used to establish
a minimum analytical cycle time. Sample handling and conditioning system practices can be found in Practice D5503.
6.3.1 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 as well as rotameters.
Temperature control is generally vital for ensuring consistent operation of these devices. The gas flow is measured by appropriate
means and adjusted as necessary. Mass flow controllers, capable of maintaining a gas flow constant to within 61 % at the flow
rates necessary for optimal instrument performance are typically used.
6.3.2 Detectors—Common detectors used for total sulfur determinations include chemiluminescence (Test Method D5504),
microcoulometry (Test Method D3246), electrochemical (Test Method D6920), lead acetate (Test Method D4468), titration, such
as barium chloride (Test Method D1072), ultra-violet fluorescence (Test Methods D5453 and D6667), both continuous and pulsed.
Other detectors can be used provided they have appropriate linearity, sensitivity, and selectivity for the selected application. In
selecting a detector, the user 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.
6.4 Data Acquisition—Data acquisition and storage can be accomplished using a number of devices and media. Following are
some examples.
6.4.1 Recorder—A 0 to 1 mV range recording potentiometer or equivalent can be used.
6.4.2 Communications—Efficient communications between the analyzer and the host depend on resolving any and all interface
issues. Signals to and from the host are typically optically isolated from each other.
7. Reagents and Materials
NOTE 1—Warning: Compressed gas standards should only be handled in well ventilated locations away from sparks and flames. Improper handling
of compressed gas cylinders containing calibration standards, air, nitrogen, hydrogen, argon or helium can result in explosion. Rapid release of nitrogen
or helium can result in asphyxiation. Compressed air supports combustion. Sulfur species and radiation sources can be toxic.
7.1 Standards—Accurate sulfur standards are required for the determination of total sulfur. Standards are available as prepared
standards in the form of a compressed gas or as a preparable standard in the form of a permeation tube calibration device.
7.2 Prepared Standards—Compressed gas standards should be stable, of the highest available accuracy and purity and used in
accordance with the manufacturer’s recommendations. The matrix components in the reference standard can be representative of
the monitored gas. Alternatively, a simplified matrix can be used if the analyzer can be calibrated in accordance with the
manufacturer’s specifications. Sulfur concentrations are dependent on the detector linearity and are typically selected between one
half and twice their expected concentration in the monitored gas. Alternatively, a critical value of sulfur concentration , such as
an alarm limit, can be used to identlify the desired total sulfur concentration of the standard. Using a sulfur specie that differs from
what the detector sees allows for a total analyzer system performance check. Standards must be maintained within the temperature
range specified by the manufacturer to ensure accuracy and stability.
7.3 Permeation Devices—Permeation devices contain an aliquot of a specific compound that continuously diffuses at a
determined rate through a permeable medium. A dry
...
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