ASTM_D_7607_-_D_7607M_-_19.pdf

Designation:D7607/D7607M19Standard Test Method forAnalysis of Oxygen in Gaseous Fuels(ElectrochemicalSensor Method)1This standard is issued under the fixed designation D7607/D7607M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method is for the determination of oxygen(O2)in gaseous fuels and fuel type gases.It is applicable to themeasurement of oxygen in natural gas and other gaseous fuels.This method can be used to measure oxygen in helium,hydrogen,nitrogen,argon,carbon dioxide,mixed gases,pro-cess gases,and ambient air.The applicable range is 0.1 ppm(v)to 25%by volume.1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard.Thevalues stated in each system are not necessarily exact equiva-lents;therefore,to ensure conformance with the standard,eachsystem shall be used independently of the other,and valuesfrom the two systems shall not be combined.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D4150 Terminology Relating to Gaseous FuelsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 For general terminology,see Terminology D4150.3.2 Definitions:3.2.1 electrochemical sensor,na chemical sensor thatquantitatively measures an analyte by the electrical outputproduced by the sensor.3.2.2 span calibration,nthe adjustment of the transmitterelectronics to the sensors signal output for a given oxygenstandard.3.2.3 zero calibration,nthe adjustment of the transmitterelectronics to the sensors signal output for a sample gascontaining less than 0.1 ppm(v)oxygen.4.Summary of Test Method4.1 Measurement of oxygen is accomplished by comparingthe electrical signal produced by an unknown sample with thatof a known standard using an oxygen specific electrochemicalsensor.A gaseous sample at constant flow and temperature ispassed over the electrochemical cell.Oxygen diffuses into thesensor and reacts chemically at the sensing electrode toproduce an electrical current output proportional to the oxygenconcentration in the gas phase.Experience has shown that thetypes of sensors supplied with equipment used in this standardtypically have a linear response over the ranges of applicationwhich remains stable during the sensors useful life.Theanalyzer consists of a sensor,a sample flow system,and theelectronics to accurately determine the sensor signal.5.Significance and Use5.1 This test method is primarily used to monitor theconcentration of oxygen in gases to verify gas quality foroperational needs and contractual obligations.Oxygen contentis a major factor influencing internal corrosion,fuel quality,gasquality,and user and operator safety.6.Interferences6.1 Interfering gases such as oxides of sulfur,oxides ofnitrogen,and hydrogen sulfide can produce false readings andreduce the expected life of the sensor.Scrubbers are used to1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.12 on On-Line/At-LineAnalysis of Gaseous Fuels.Current edition approved Nov.15,2019.Published January 2020.Originallyapproved in 2011.Last previous edition approved in 2011 as D7607/D7607M111.DOI:10.1520/D7607_D7607M-19.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.remove these compounds.Special sensors suitable for gascontaining high fractions of carbon dioxide are available frommanufacturers.7.Apparatus7.1 SensorThe sealed sensor is co