ASTM D6021-2012(2017) 4375 Standard Test Method for Measurement of Total Hydrogen Sulfide in Residual Fuels by Multiple Headspace Extraction and Sulfur Specific Detection《用复式顶端空间萃取.pdf

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1、Designation: D6021 12 (Reapproved 2017)Standard Test Method forMeasurement of Total Hydrogen Sulfide in Residual Fuelsby Multiple Headspace Extraction and Sulfur SpecificDetection1This standard is issued under the fixed designation D6021; the number immediately following the designation indicates th

2、e year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a method suitable for meas

3、uringthe total amount of hydrogen sulfide (H2S) in heavy distillates,heavy distillate/residual fuel blends, or residual fuels as definedin Specification D396 Grade 4, 5 (Light), 5 (Heavy), and 6,when the H2S concentration in the fuel is in the 0.01 gg(ppmw) to 100 gg (ppmw) range.1.2 The values stat

4、ed in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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, he

5、alth, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific warning statements, see 7.5, 8.2, 9.2, 10.1.4, and11.1.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization es

6、tablished 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:2D396 Specification for Fuel OilsD1193 Specification for Reag

7、ent WaterD2420 Test Method for Hydrogen Sulfide in LiquefiedPetroleum (LP) Gases (Lead Acetate Method)D3609 Practice for Calibration Techniques Using Perme-ation TubesD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4084 Test Method for Analysis of Hydrogen Sulfide inGaseous Fue

8、ls (Lead Acetate Reaction Rate Method)D4323 Test Method for Hydrogen Sulfide in theAtmosphereby Rate of Change of ReflectanceD5504 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and ChemiluminescenceD5705 Test Method for Measurement of Hydrog

9、en Sulfidein the Vapor Phase Above Residual Fuel OilsD7621 Test Method for Determination of Hydrogen Sulfidein Fuel Oils by Rapid Liquid Phase Extraction3. Terminology3.1 Definitions:3.1.1 heavy distillate, na fuel produced from the distilla-tion of crude oil which has a kinematic viscosity at 40 Cb

10、etween 5.5 mm2/s and 24.0 mm2/s, inclusive.3.1.2 heavy distillate/residual fuel blend, na blend ofheavy distillate and residual fuel oil having a viscosity at 40 Cbetween 5.5 mm2/s and 24.0 mm2/s, inclusive.3.1.3 multiple headspace extraction, na technique to de-termine the total concentration of a

11、gas trapped in a liquid byanalysis of successive gas extractions from the vapor space ofa closed vessel containing a known amount of the sample.3.1.4 residual fuel oil, nany liquid or liquefiable petro-leum product having a kinematic viscosity at 100 C between5.0 mm2/s and 50.0 mm2/s, inclusive, bur

12、ned for the generationof heat in a furnace or firebox or for the generation of power inan engine.4. Summary of Test Method4.1 A representative sample of residual fuel oil is obtainedin sufficient quantity to completely fill the sample container.The sample is taken to the laboratory preferably within

13、 one to4 h, within 24 h maximum and placed in a refrigerator until thehydrogen sulfide analysis can be run. At that time, the sample1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02

14、.14 on on Stability, Cleanliness and Compatibility of LiquidFuels.Current edition approved Oct. 1, 2017. Published November 2017. Originallyapproved in 1996. Last previous edition approved in 2012 as D602112. DOI:10.1520/D6021-12R17.2For referenced ASTM standards, visit the ASTM website, www.astm.or

15、g, 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 internatio

16、nal 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) Committe

17、e.1is removed from the refrigerator and allowed to sit at ambienttemperature until it flows freely.4.2 A 0.05 g to 5.0 g test specimen (aliquot) is placed in aheadspace vial and heated in an oven at 60 C for more thanfive but less than 15 min. The headspace gas is sampled andinjected into either of

18、two types of apparatus capable ofmeasuring the hydrogen sulfide concentration in the gaseoussample.3The two types of apparatus are those using thereaction of lead acetate with H2S (see Test Method D4084 orTest Method D4323) and those based on chemiluminescence(see Test Method D5504).4.3 The remainin

19、g contents of the headspace vial are cooledfor 5 min, then again heated in the oven. The headspacecontents are again transferred to the hydrogen sulfide measur-ing instrument. The procedure is repeated for a third time. Thisis known as multiple headspace extraction procedure (MHE).4.4 Alinear plot o

20、f the natural logarithm of the area or peakheight difference of the instrument reading against the numberof injections is indicative of the correctness of the extractionprocedure. The difference in area or peak height of the first twoinjections is used to calculate a total area or total peak heightd

21、ifference. The total area or total peak height difference ismultiplied by a response factor determined from a direct gascalibration mixture and divided by the weight of the testspecimen to determine the concentration of H2S in the residualfuel in g/g (ppmw).5. Significance and Use5.1 Residual fuel o

22、ils can contain H2S in the liquid phase,and this can result in hazardous vapor phase levels of H2Sinstorage tank headspaces. The vapor phase levels can varysignificantly according to the headspace volume, fueltemperature, and agitation. Measurement of H2S levels in theliquid phase provides a useful

23、indication of the residual fueloils propensity to form high vapor phase levels, and lowerlevels in the residual fuel oil will directly reduce risk of H2Sexposure. It is critical, however, that anyone involved inhandling fuel oil, such as vessel owners and operators, continueto maintain appropriate s

24、afety practices designed to protect thecrew, tank farm operators and others who can be exposed toH2S.5.1.1 The measurement of H2S in the liquid phase isappropriate for product quality control, while the measurementof H2S in the vapor phase is appropriate for health and safetypurposes.5.2 This test m

25、ethod was developed so refiners, fuel termi-nal operators and independent testing laboratory personnel cananalytically measure the amount of H2S in the liquid phase ofresidual fuel oils.NOTE 1Test Method D6021 is one of three test methods forquantitatively measuring H2S in residual fuels:1) Test Met

26、hod D5705 is a simple field test method for determining H2Slevels in the vapor phase.2) Test Method D7621 is a rapid test method to determine H2S levels inthe liquid phase.5.3 H2S concentrations in the liquid and vapor phase at-tempt to reach equilibrium in a static system. However, thisequilibrium

27、and the related liquid and vapor concentrations canvary greatly depending on temperature and the chemicalcomposition of the liquid phase. A concentration of 1 mg/kg(g/g) (ppmw) of H2S in the liquid phase of a residual fuel cantypically generate an actual gas concentration of50 LL(ppmv) to 100 L/L(pp

28、mv) of H2S in the vaporphase, but the equilibrium of the vapor phase is disrupted themoment a vent or access point is opened to collect a sample.NOTE 2Because of the reactivity, absorptivity, and volatility of H2Sany measurement method only provides an H2S concentration at a givenmoment in time.6. A

29、pparatus6.1 A schematic of the headspace sampling system requiredfor this analysis is shown in Fig. 1. It consists of:6.1.1 Sampling On/Off Valve, with 3.2 mm o.d. connector(Valve 1).6.1.2 Six-Port External Loop Injection Valve, made with316 stainless steel, resistant to attack by sulfur compounds a

30、ndhaving 3.2 mm o.d. tubing from each port (Valve 2).6.1.3 Polytetrafluoroethylene (PTFE) Sample Loops, of0.5 mL, 2.5 mL, and 10 mL are used for H2S content of1 ppmw to 100 ppmw, 0.1 ppmw to 50 ppmw, and 0.01 ppmwto 10 ppmw, respectively.6.1.4 Pressure/Vacuum Gauge, 6.3 mm diameter dial typewith ran

31、ge of 100 kPag to 200 kPag, 5 kPa divisions from100 kPag to 0 kPag and 10 kPa divisions from 0 kPag to200 kPag.6.1.5 Vacuum On/Off Valve, 3.2 mm o.d. connector (Valve3).6.1.6 Sulfur Selective Detector, any H2S specific detectorcapable of measuring H2S in the gas from 1 ppmv to10 000 ppmv with a repe

32、atability of 62 % of full scale.NOTE 3Good performance has been obtained with a lead acetate tapedetector and a sulfur chemiluminescence detector.6.1.7 Fluorocarbon Tubing, 0.6 m long by 3.2 mm o.d. toconnect components together.6.2 Vacuum pump, 3.2 mm o.d. outlet, capable of achievinga 0.2 kPa vacu

33、um and with a capacity of 100 mL/min.6.3 Headspace Oven, capable of operating at 60 C 60.5 C with internal dimensions of 30 cm by 30 cm by 30 cm.An optional vent line is recommended in case a vial leaks.6.4 Analytical Balance, sensitivity of 0.01 mg, maximumweight of 250 g.6.5 Data Handling System,

34、such as electronic integrator orany computer unit that can work with a chromatographicsignal.6.6 If sulfur specific detectors are used instead of an H2Sanalyzer then a chromatographic system equipped with asuitable column and oven is required to separate H2S fromother sulfur compounds (see Test Meth

35、od D5504).3Determination of H2S in Residual Fuel Oils by Multiple Headspace Extraction:A Critical Evaluation of Available Analytical Methods. Silva, B., Carvajal, N.,Gonzalez, A., Eastern Analytical Symposium, sponsored by American ChemicalSociety and the American Microchemical Society, November 162

36、0, 1992,Somerset, N.J.D6021 12 (2017)26.7 Hand Crimper, to crimp 20 mm diameter aluminumseals.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee o

37、nAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Acetic Acid SolutionAdd 50 m

38、L of glacial acetic acid(CH3COOH) toa1Lvolumetric flask and then add Type IIdistilled water, as specified in Specification D1193,tothe1Lmark to make a 5 % acetic acid solution.7.3 Aluminum Seals, 20 mm diameter to seal septas toheadspace sample vials.7.4 Headspace Vials, 30 mL, 60 mL, or 120 mLboros

39、ilicateglass vials with 20 mm mouth diameter.7.5 Hydrogen Sulfide Gas Calibration Standard, 1 LL,10 LL, and 100 L/LH2S in helium or nitrogen high pressurecylinders (obtain from gas supply company). (WarningHydrogen sulfide is an extremely toxic gas.)7.6 Gases, helium or nitrogen (H2S free), chemical

40、ly puregrade or purified, as carrier gas to sweep sample into thedetector.7.7 Lead Acetate Sensing PaperPrepare in accordancewith Test Method D2420, using appropriate size strips anddrying in an H2S-free environment. Commercially availabletest paper has been found satisfactory.NOTE 4Reagents from 7.

41、2 and 7.7 are only needed if using an H2Slead acetate tape detector.7.8 Nuts and Ferrules, Polytetrafluoroethylene (PTFE) andstainless steel (3.2 mm).7.9 Septas, 20 mm diameter PTFE silicone/fluorocarbon toseal headspace sample vials.7.10 Side Port Needles, for pressure lock,A-gas series (withreduct

42、ion union 3.2 mm to 1.6 mm).7.11 Syringe Needles, common dischargeable (dosingneedle).8. Sampling8.1 Using a suitable H2S inert container of 250 mL to500 mL, collect a representative sample by Practice D4057.Suitable containers can be made of borosilicate glass or4Reagent Chemicals, American Chemica

43、l Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharm

44、acopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Schematic of Headspace Analysis SystemD6021 12 (2017)3aluminum. If the sample temperature is below 60 C then ahigh density polyethylene bottle can be used.8.2 Fill the container completely to the top so that there isno headspace in the container.

45、 Cap immediately. (WarningAt no time should the container temperature be allowed toexceed the temperature of the sample at the time.)8.3 Take the samples to the laboratory preferably within oneto four hours, within 24 h maximum. Place the samples inrefrigerated storage. Store samples until analysis

46、time but notmore than three days.9. Preparation of Apparatus9.1 Assemble the headspace sampling system as shown inFig. 1.9.2 Because of the chemical activity and adsorptive proper-ties of H2S, it is highly desirable to connect the components ofthe test apparatus together using minimum lengths of alu

47、mi-num or fluorocarbon sample lines. (WarningTo preclude theformation of mercaptide gels and to reduce problems associ-ated with corrosion do not use brass or copper flow systemparts.)10. Calibration and Standardization10.1 Filling Head Space Vial With Gas Calibration Stan-dard:10.1.1 Depending on t

48、he expected concentration use, a1LL (0.1 g/g) in a 120-mL headspace vial, 10 LL(;1 gg) in a 60 mL headspace vial, or 100 LL (;10 gg)in a 30 mL headspace vial, H2S gas standard to calibrate theheadspace sampling system.NOTE 5Parts per million by volume units (L/L), equivalent to micromoles per mole,

49、are used because of the convenience in use of volumemeasurements rather than weight for a gas standard.10.1.2 Insert a silicone/fluorocarbon septum, with the PTFEside pointing inwards, into the headspace vial, cover it with analuminum seal, and crimp the aluminum seal with the handcrimper.10.1.3 Insert the inlet needle attached to the H2S calibrationcylinder (see Fig. 2) through the septum with the flow controlset to zero. Also insert an open syringe needle into the septumas an outlet vent.10.1.4 Set the pressure of the H2S cali