1、Designation: D 6021 06An American National StandardStandard Test Method forMeasurement of Total Hydrogen Sulfide in Residual Fuelsby Multiple Headspace Extraction and Sulfur SpecificDetection1This standard is issued under the fixed designation D 6021; the number immediately following the designation
2、 indicates the 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a method su
3、itable for measuringthe total amount of hydrogen sulfide (H2S) in heavy distillates,heavy distillate/residual fuel blends, or residual fuels as definedin Specification D 396 Grade 4, 5 (Light), 5 (Heavy), and 6,when the H2S concentration in the fuel is in the 0.01 to 100g/g (ppmw) range.1.2 The valu
4、es stated 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 saf
5、ety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificwarning statements, see 5.1, 7.5, 8.2, 9.2, 10.1.4, and 11.1.2. Referenced Documents2.1 ASTM Standards:2D 396 Specification for Fuel OilsD 1193 Specification for Reagent WaterD 2420 Test Met
6、hod for Hydrogen Sulfide In LiquefiedPetroleum (LP) Gases (Lead Acetate Method)D 3609 Practice for Calibration Techniques Using Perme-ation TubesD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4084 Test Method for Analysis of Hydrogen Sulfide inGaseous Fuels (Lead Acetate Rea
7、ction Rate Method)D 4323 Test Method for Hydrogen Sulfide in the Atmo-sphere by Rate of Change of ReflectanceD 5504 Test Method for Determination of Sulfur Com-pounds in Natural Gas and Gaseous Fuels by Gas Chro-matography and ChemiluminescenceD 5705 Test Method for Measurement of Hydrogen Sulfidein
8、 the Vapor Phase Above Residual Fuel Oils3. Terminology3.1 Definitions:3.1.1 heavy distillate, na fuel produced from the distilla-tion of crude oil which has a kinematic viscosity at 40Cbetween 5.5 and 24.0 mm2/s, inclusive.3.1.2 heavy distillate/residual fuel blend, na blend ofheavy distillate and
9、residual fuel oil having a viscosity at 40Cbetween 5.5 and 24.0 mm2/s, inclusive.3.1.3 multiple headspace extraction, na technique to de-termine the total concentration of a gas trapped in a liquid byanalysis of successive gas extractions from the vapor space ofa closed vessel containing a known amo
10、unt of the sample.3.1.4 residual fuel oil, nany liquid or liquefiable petro-leum product having a kinematic viscosity at 100C between5.0 and 50.0 mm2/s, inclusive, burned for the generation ofheat in a furnace or firebox or for the generation of power in anengine.4. Summary of Test Method4.1 A repre
11、sentative sample of residual fuel oil is obtainedin sufficient quantity to completely fill the sample container.The sample is taken to the laboratory preferably within one to4 h, within 24 h maximum and placed in a refrigerator until thehydrogen sulfide analysis can be run. At that time, the samplei
12、s removed from the refrigerator and allowed to sit at ambienttemperature until it flows freely.4.2 A 0.05 to 5.0 g test specimen (aliquot) is placed in aheadspace vial and heated in an oven at 60C for more than fivebut less than 15 min. The headspace gas is sampled andinjected into either of two typ
13、es of apparatus capable ofmeasuring the hydrogen sulfide concentration in the gaseoussample.3The two types of apparatus are those using the1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.E0 on B
14、urner, Diesel, Non-Aviation Gas Turbine, and Marine Fuels.Current edition approved Aug. 1, 2006. Published September 2006. Originallyapproved in 1996. Last previous edition approved in 2001 as D 602196(2001)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custo
15、mer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Determination of H2S in Residual Fuel Oils by Multiple Headspace Extraction:A Critical Evaluation of Available Analytical Methods. Silva, B., Carvajal
16、, N.,Gonzalez, A., Eastern Analytical Symposium, sponsored by American ChemicalSociety and the American Microchemical Society, November 1620, 1992, Somer-set, N.J.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
17、 Conshohocken, PA 19428-2959, United States.reaction of lead acetate with H2S (see Test Method D 4084 orTest Method D 4323) and those based on chemiluminescence(see Test Method D 5504).4.3 The remaining contents of the headspace vial are cooledfor 5 min, then again heated in the oven. The headspacec
18、ontents 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 of the natural logarithm of the area or peakheight difference of the instrument reading against the
19、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 heightdifference. The total area or total peak height difference ismultiplied by a response factor determi
20、ned 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 Excessive levels of hydrogen sulfide in the vapor phaseabove residual fuel oils in storage tanks may result in hea
21、lthhazard, OSHA limits violation, and public complaint. Anadditional concern is corrosion that can be caused by thepresence of H2S during refining and other production activities.Control measures to maintain safe levels of H2S require aconsistent method for the assessment of potentially hazardouslev
22、els of H2S in fuel oils. (WarningH2S is a highly toxicsubstance. Extreme care must be used in the sampling andhandling of samples that are suspected of containing highlevels of H2S.)5.2 Aconcentration of 0.1 g/g (ppmw) of H2S in the liquidphase of a No. 4, 5, or 6 residual fuel oil can generate an a
23、ctualgas concentration of 10 to 100 L/L(ppmv) of H2S in the vaporphase; therefore an accurate analytical method is required todetermine the total H2S concentration of these residual fueloils. This test method was developed so refiners, fuel terminaloperators, and independent testing laboratory perso
24、nnel cananalytically measure the amount of H2S in residual fuel oils.5.3 Test Method D 5705 provides a simple and consistentfield test method for the rapid determination of H2Sintheresidual fuel oils storage tank vapor phase. However, it doesnot necessarily simulate the vapor phase H2S concentration
25、 ofa fuel storage tank nor does it provide any indication of theliquid phase H2S concentration. This test method provides aquantitative measure of a residual fuel oils liquid phase H2Sconcentration. It requires a laboratory and a skilled operator toperform the test but gives a more quantitative indi
26、cation ofpotential H2S exposure than Test Method D 5705.NOTE 1Because of the reactivity, absorptivity, and volatility of H2Sany measurement method only provides an H2S concentration at a givenmoment in time.6. Apparatus6.1 A schematic of the headspace sampling system requiredfor this analysis is sho
27、wn in Fig. 1. It consists of:FIG. 1 Schematic of Headspace Analysis SystemD60210626.1.1 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 andhaving 3.2 mm o.d. tubing from eac
28、h port (Valve 2).6.1.3 Polytetrafluoroethylene (PTFE) Sample Loops, of 0.5,2.5, and 10 mL are used for H2S content of 1 to 100, 0.1 to 50,and 0.01 to 10 ppmw, respectively.6.1.4 Pressure/Vacuum Gage, 6.3 mm diameter dial typewith range of 100 to 200 kPag, 5 kPa divisions from 100 to0 and 10 kPa divi
29、sions from 0 to 200 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 to 10 000 ppmvwith a repeatability of 62 % of full scale.NOTE 2Good performance has been obtained with a lead acetat
30、e 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 vacuum and with a capacity of 100 mL/min.6.3 Headspace Oven, capable of operating at 60 6 0.5Cw
31、ith internal dimensions of 30 by 30 by 30 cm. An optionalvent 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, such as electronic integrator orany computer unit that can work with a chromatographicsignal.6.6 If
32、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 Method D 5504).6.7 Hand Crimper, to crimp 20 mm diameter aluminumseals.7. Reagents and Materials7.1 Puri
33、ty of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided
34、 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 mL of glacial acetic acid(CH3COOH) to a 1-L volumetric flask and then add Type IIdistilled water, as specified in Specification
35、D 1193, to the 1-Lmark 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-, 60-, or 120-mL borosilicate glassvials with 20 mm mouth diameter.7.5 Hydrogen Sulfide Gas Calibration Standard , 1, 10, and100 L/L H2S in hel
36、ium or nitrogen high pressure cylinders(obtain from gas supply company). (WarningHydrogensulfide is an extremely toxic gas.)7.6 Gases, helium or nitrogen (H2S free), chemically puregrade or purified, as carrier gas to sweep sample into thedetector.7.7 Lead Acetate Sensing PaperPrepare in accordancew
37、ith Test Method D 2420, using appropriate size strips anddrying in an H2S-free environment. Commercially availabletest paper has been found satisfactory.NOTE 3Reagents from 7.2 and 7.7 are only needed if using an H2Slead acetate tape detector.7.8 Nuts and Ferrules, Polytetrafluoroethylene (PTFE) and
38、stainless 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 (withreduction union 3.2 mm to 1.6 mm).7.11 Syringe Needles, common dischargeable (dosingneedle).8. Sampling8.1 Using a suitable H2S ine
39、rt container of 250 to 500 mL,collect a representative sample by Practice D 4057. Suitablecontainers can be made of borosilicate glass or aluminum. Ifthe sample temperature is below 60C then a high densitypolyethylene bottle can be used.8.2 Fill the container completely to the top so that there isno
40、 headspace in the container. Cap immediately.(WarningAt no time should the container temperature beallowed to exceed 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. St
41、ore samples until analysis 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 u
42、sing minimum lengths of alumi-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
43、-dard:10.1.1 Depending on the expected concentration use, a 1L/L (#0.1 g/g) in a 120-mL headspace vial, 10 L/L (;1g/g) in a 60-mL headspace vial, or 100 L/L (;10 g/g) in a30-mL headspace vial, H2S gas standard to calibrate theheadspace sampling system.4Reagent Chemicals, American Chemical Society Sp
44、ecifications, 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. Pharmacopeial Con
45、vention, Inc. (USPC), Rockville,MD.D6021063NOTE 4Parts per million by volume units (L/L), equivalent to micromoles per mole, 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
46、 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 sept
47、umas an outlet vent.10.1.4 Set the pressure of the H2S calibration cylinder to105 kPa, and open the flow control to purge the vial as follows:(WarningBecause of the toxicity of H2S the vial should bein a hood during the purging operation.)30-mL vialpurge for 3 min at a flow of 100 mL/min.60-mL vialp
48、urge for 6 min at a flow of 100 mL/min.120-mL vialpurge for 10 min at a flow of 120 mL/min.10.1.5 Turn the flow control to zero flow and remove theinlet needle, leaving the outlet vent in the vial.10.1.6 Allow the vial to equilibrate to atmospheric pressurefor 1.0 min, then remove the outlet vent.10
49、.1.7 Record the laboratory ambient temperature in C andthe laboratory barometric pressure in kPa.10.1.8 Immediately after preparing a calibration standardobtain its analyzer response as shown in 10.2.1-10.2.7.NOTE 5Alternative methods for preparing a calibration standardinclude: heating a solid to generate H2S and then using a permeation tubeas discussed in Practice D 3609 or using pure H2S and a movable pistonas discussed in Test Method D 4084.10.2 Calibration of Analyzer:10.2.1 Place the headspace vial in a 60C oven for at least5 min but fo
