ASTM D7166-05
(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
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 standard. Values stated in other units are for information only.
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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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information.
Designation:D7166–05
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.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D5503 PracticeforNaturalGasSample-HandlingandCon-
ditioning Systems for Pipeline Instrumentation
1.1 Thispracticeisforthedeterminationoftotalsulfurfrom
D5504 Test Method for Determination of Sulfur Com-
volatile sulfur-containing compounds in high methane or
pounds in Natural Gas and Gaseous Fuels by Gas Chro-
hydrogen content gaseous fuels using on-line/at-line instru-
matography and Chemiluminescence
mentation.
D6122 Practice for Validation of the Performance of Mul-
1.2 The values stated in SI units are standard. Values stated
tivariate Process Infrared Spectrophotometer Based Ana-
in other units are for information only.
lyzer 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 PracticeforPerformanceTestingofProcessAnalyz-
bility of regulatory limitations prior to use.
ers for Aromatic Hydrocarbon Materials
2. Referenced Documents D6667 Test Method for Determination of Total Volatile
Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum
2.1 ASTM Standards:
Gases by Ultraviolet Fluorescence
D1070 TestMethodsforRelativeDensityofGaseousFuels
D6920 Test Method for Total Sulfur in Naphthas, Distil-
D1072 Test Method for Total Sulfur in Fuel Gases by
lates, Reformulated Gasolines, Diesels, Biodiesels, and
Combustion and Barium Chloride Titration
Motor Fuels by Oxidative Combustion and Electrochemi-
D3246 Test Method for Sulfur in Petroleum Gas by Oxida-
cal Detection
tive Microcoulometry
D3609 Practice for Calibration Techniques Using Perme-
3. Terminology
ation Tubes
3.1 Definitions:
D3764 Practice for Validation of the Performance of Pro-
3.1.1 direct sampling—sampling where there is no direct
cess Stream Analyzer Systems
connection between the medium to be sampled and the
D4298 Guide for Intercomparing Permeation Tubes to Es-
analytical unit.
tablish Traceability
3.1.2 in-line instrument—instrumentwithanactiveelement
D4468 Test Method for Total Sulfur in Gaseous Fuels by
installed in a pipeline, which is used to measure pipeline
Hydrogenolysis and Rateometric Colorimetry
contents or conditions.
D5287 Practice for Automatic Sampling of Gaseous Fuels
3.1.3 on-line instrument—instrument that samples gas di-
D5453 Test Method for Determination of Total Sulfur in
rectly from a pipeline, but is installed externally.
Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel
3.1.4 at-line instrument—instrumentation requiring opera-
Engine Fuel, and Engine Oil by Ultraviolet Fluorescence
tor interaction that samples gas directly from the pipeline.
3.1.5 continuous fuel monitor—instrument that samples gas
directly from the pipeline on a continuous or semi-continuous
This practice is under the jurisdiction of ASTM Committee D03 on Gaseous
basis.
Fuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-Line
3.1.6 total reduced sulfur (TRS)—concentration summation
Analysis of Gaseous Fuels.
ofallvolatilesulfurspecieswitha−2sulfuroxidationnumber,
Current edition approved June 15, 2005. Published June 2005. DOI: 10.1520/
D7166-05.
excluding sulfur dioxide, sulfones and other inorganic sulfur
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
compounds.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.1.7 total sulfur—concentration summation of all volatile
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sulfur species in a sample.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7166–05
3.1.8 volatile—molecular characteristic wherein the sulfur suitable inert, or passivated, materials to ensure constituents in
specieexistsinthegasphaseattheoperatingconditionsofthe the fuel stream do not degrade these components or alter the
process or pipeline. composition of the sampled gas.
6.2 Sample Probes/Sample Extraction—The location and
4. Summary of Practice
orientation of sampling components are critical for ensuring
that a representative sample is analyzed. The locations and
4.1 Arepresentative sample of the gaseous fuel is extracted
from a process pipe or pipeline and is transferred in a timely orientation of sampling components should be selected based
upon sound analytic and engineering considerations. Sampling
manner through an appropriately designed sampling system to
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
6.3 Sample Inlet System— The siting and installation of an
content. A precisely measured volume of sample is either
at-line or on-line monitor is critical for collecting representa-
injected, or allowed to flow continuously, either directly into
tive information on sulfur content. Factors that should be
the analyzer or into a carrier gas, as required by the analyzer.
considered in siting an instrument include ease of calibration,
Some total sulfur analyzer systems are configured such that
ease of access for repair or maintenance, sample uniformity at
sample gas flows directly into the analyzer detection system.
the sampling point, appropriateness of samples from a sam-
Excess process or pipeline sample is vented to atmosphere, to
pling location, ambient conditions, and of course safety issues.
flare or to the process stream dependant upon application and
An automated gas sampling valve is required in many appli-
regulatory requirements.
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
maintainedasaparticulateandcondensatefreegas.Heatingat
maybeoxidativeorreductiveandmayrequiretheintroduction
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
intothedetectorwherequantificationofthetotalsulfurcontent
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
the process bandwidth is critical to ensuring that the reported
5.1 On-line, at-line, in-line and other near-real time moni-
toringsystemsthatmeasurefuelgascharacteristicssuchasthe analytical results adequately represent the process being moni-
tored. The Nyquist-Shannon sampling criterion of a sampling
totalsulfurcontentareprevalentinthenaturalgasandfuelgas
industries. The installation and operation of particular systems frequency that exceeds twice the process bandwidth can be
used to establish a minimum analytical cycle time. Sample
varyonthespecificobjectives,contractualobligations,process
type, regulatory requirements, and internal performance re- handling and conditioning system practices can be found in
Practice D5503.
quirements needed by the user. This protocol is intended to
provide guidelines for standardized start-up procedures, oper-
6.3.1 Carrier and Detector Gas Control—Constant flow
ating procedures, and quality assurance practices for on-line,
controlofcarrieranddetectorgasesiscriticalforoptimumand
at-line, in-line and other near-real time total sulfur monitoring
consistent analytical performance. Control is achieved by use
systems.
of pressure regulators and fixed flow restrictors as well as
rotameters. Temperature control is generally vital for ensuring
6. Apparatus
consistentoperationofthesedevices.Thegasflowismeasured
by appropriate means and adjusted as necessary. Mass flow
6.1 Instrument—Any instrument of standard manufacture,
controllers, capable of maintaining a gas flow constant to
with hardware necessary for interfacing to a natural gas,
within 61%attheflowratesnecessaryforoptimalinstrument
hydrogen or other fuel gas pipeline and containing all the
performance are typically used.
features necessary for the intended application(s) can be used.
6.1.1 Specific Sulfur Specie Detection Systems—The oper- 6.3.2 Detectors—Common detectors used for total sulfur
ating parameters employed generally must be capable of determinations include chemiluminescence (Test Method
converting all of the volatile sulfur species in the sample into D5504),microcoulometry(TestMethodD3246),electrochemi-
a single detectable species such as sulfur dioxide or hydrogen cal (Test Method D6920), lead acetate (Test Method D4468),
sulfide. Instrumentation must satisfy or exceed other analytic titration, such as barium chloride (Test Method D1072),
performance characteristics for accuracy and precision for the ultra-violet fluorescence (Test Methods D5453 and D6667),
intended application without encountering unacceptable inter- both continuous and pulsed. Other detectors can be used
ferenceorbias.Inaddition,componentsincontactwithsample provided they have appropriate linearity, sensitivity, and selec-
streams such as tubing and valving must be constructed of tivity for the selected application. In selecting a detector, the
D7166–05
usershouldconsiderthelinearity,sensitivity,andselectivityof 8. Equipment Siting and Installation
particular detection systems prior to installation. The user
8.1 Asampleinletsystemcapableofoperatin
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