1、Designation: D7041 16Standard Test Method forDetermination of Total Sulfur in Liquid Hydrocarbons andHydrocarbon-Oxygenate Blends by Gas Chromatographywith Flame Photometric Detection1This standard is issued under the fixed designation D7041; the number immediately following the designation indicate
2、s 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 () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of
3、total sulfurin liquid hydrocarbons with a final boiling point less than450 C by gas chromatography using a flame photometricdetector.1.2 This test method is applicable for total sulfur levels from0.5 mg S/kg to 100 mg S/kg.NOTE 1The pooled limit of quantification (PLOQ) derived from the2002 interlab
4、oratory cooperative test program was determined to be1 mgS kg.NOTE 2Samples can also be tested at other total sulfur levels, but theprecision statements may not apply.1.3 The values stated in SI units are to be regarded asstandard.1.4 This standard does not purport to address all of thesafety concer
5、ns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements see Section 7.2. Referenced Documents2.1 ASTM Standar
6、ds:2D1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD4057 Practice for Manual Sampling of Petroleum andPetroleum Pro
7、ductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsE840 Practice for Using Flame Photometric Detectors in GasChromatography3. Summary of Test Method3.1 The sample is analyzed by gas chromatography with aflame photometric detector. A fixed amount of sample isinjected into th
8、e gas chromatograph where it is vaporized. Theair carrier stream carries the vaporized sample into a hightemperature zone (900 C) where the compounds present inthe sample are oxidized. Sulfur compounds are converted tosulfur dioxide (SO2). The carrier stream carries the oxidationcomponents onto a ch
9、romatographic column where they areseparated and the SO2is quantified by the flame photometricdetector. Calibration of the detector is achieved by the use of anappropriate external standard.4. Significance and Use4.1 This test method can be used to determine total sulfurlevels in process feeds and f
10、inished products that fall within thescope of this test method.4.2 Low levels of sulfur in process feed stocks can poisonexpensive catalysts used in petroleum refining processes. Thistest method can be used to monitor sulfur levels in thesefeedstocks.5. Apparatus5.1 Gas Chromatograph, equipped with
11、automatically con-trolled valves, capable of automatic calibration with an exter-nal standard and having a flame photometric detector with anoverall sensitivity to detect at least 0.5 mg/kg of SO2. It mustbe able to automatically control all valve switching times.Although originally developed with o
12、nline analytical measure-ment equipment in an offline mode of operation, suitable onlineor laboratory gas chromatographs may apply this test methodas described. Typical instrument parameters are listed in Table1.5.1.1 Carrier and Detector Gas ControlThe chromato-graph must be equipped with flow cont
13、rollers or pressurecontrollers capable of maintaining a constant supply of carriergas and detector supply gases. Electronic pressure or flowcontrol is highly recommended.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the di
14、rect responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved April 1, 2016. Published April 2016. Originallyapproved in 2004. Last previous edition approved in 2010 as D7041 04 (2010)1.DOI: 10.1520/D7041-16.2For referenced ASTM standards, visit the ASTM website, www.astm.
15、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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C
16、700, West Conshohocken, PA 19428-2959. United States15.1.2 Sample Injection SystemAn automatic sample injec-tion device is required. The injector must allow the introduc-tion of small sample sizes (0.1 Lto 1 L). The sample must beaccurately and repeatably injected into the gas chromatograph.Rotary o
17、r stem type liquid injection valves or auto injectors arerecommended. The valve or injector must be equipped with aheated vaporizer section capable of being heated to at least285 C.5.2 Pyrolysis FurnaceA furnace capable of maintaining asufficient temperature (900 C) to pyrolyze the entire sampleand
18、oxidize the sulfur compounds to SO2.5.3 Quartz Combustion TubeQuartz tube capable of with-standing temperatures up to 1200 C. The oxidation sectionshall be large enough to ensure complete oxidation of thesample.5.4 ColumnA column that can provide complete separa-tion of SO2from the CO2quench and the
19、 other oxidizedcomponents such as H2O.5.5 DetectorAny flame photometric detector (FPD) canbe used, provided it can detect a minimum peak height twicethat of the baseline noise for a 1 L injection of a 0.5 mg S/kgstandard. Detector linearity shall be at least equal to or greaterthan 103. The user is
20、referred to Practice E840 for assistance inoptimizing the operation and performance of the FPD.5.6 Data Acquisition SystemUse any integrator or com-puterized data acquisition system for peak area integration, aswell as for recording the chromatographic trace. The deviceand software must have the fol
21、lowing capabilities:5.6.1 Identification of peak by retention time.5.6.2 Calculation and use of response factors.5.6.3 External standard calibration calculation.5.6.4 Graphic presentation of the chromatogram.5.7 Analytical BalanceAny balance capable of accuratelyweighing materials to the nearest 0.0
22、1 mg.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications a
23、re available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Carrier-GasZero grade air is recommended.(WarningCompressed air is a gas under high pressure thatsupports co
24、mbustion.)6.3 HydrogenChromatographic grade recommended,minimum purity 99.995 %. (WarningHydrogen is an ex-tremely flammable gas under high pressure.)6.4 Solvent (Reagent Grade)the solvent chosen should becapable of dissolving the sulfur-containing compound used toprepare the standard. The solvent o
25、f choice should have adensity similar to the samples being analyzed and it shouldhave sulfur concentrations less than the instrument detectionlimit. Mixed solvents such as an isooctane / toluene mixturecan be used to reach the desired density. (WarningSolventsused as reagents such as toluene and iso
26、 octane are flammableand may be harmful or fatal if ingested or inhaled.)6.5 Standards for Calibration and Peak IdentificationStandards are used for peak identification and retention timedetermination. Also standards of known concentrations arerequired for external standard calibration of the gas ch
27、romato-graph.6.5.1 Preparation of Stock Solution (mass/volume), 100 gS/mL (see Notes 3 and 4). Accurately weigh to the nearest0.1 mg, 0.0456 g of butyl sulfide into a suitable container suchas a 100 mL volumetric flask. Dilute to volume with theselected solvent. This stock solution can be further di
28、luted tothe desired sulfur concentration. Other sulfur containing com-pounds such as thiophene or thianaphthene can be substitutedfor n-butyl sulfide if desired. The concentration of the stocksolution can be calculated as follows:g S/mL 5 M 332.06! 3 1 3106!g/g!/100 mL 3 FW! (1)where:M = exact mass
29、of sulfur reference compound (g), andFW = formula weight of sulfur reference compound.NOTE 3Commercial standards can be used provided they are checkedfor accuracy.NOTE 4Stock solutions will have a shelf life of approximately 2 to 3months and should be remixed accordingly.6.5.2 Preparation of Stock S
30、olution: (mass/mass), 100 gS/g (see Notes 3 and 4). Accurately weigh to the nearest0.1 mg, 0.0456 g of butyl sulfide into a suitable container. Add100 g (accurately weighed to the nearest 0.1 g) of the selectedsolvent. This stock solution can be further diluted to the desiredsulfur concentration. Ot
31、her sulfur containing compounds suchas thiophene or thianaphthene can be substituted for butylsulfide if desired. The concentration of the stock solution canbe calculated as follows:3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestion
32、s 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 Pharmacopoeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.TABLE 1 Typical Instrument Paramet
33、ersCarrier gas Zero airCarrier flow rate 30 mL/minHydrogen flow rate 60 mL/minDetector Flame photometric detectorDetector temperature 120 CInjector temperature 285 CFurnace temperature 1000 CColumn 40 ft by18 in. stainless steeltubing,12 % polyphenyl ether/1.5 %H3PO4on 40/60 Chromosorb TColumn tempe
34、rature 115 CD7041 162mgS/kg 5 M 332.06! 3 1 3106!mg/kg!/100 g 3 FW! (2)6.6 Butyl SulfideFW 146.29, 21.92 % (m/m) S.6.7 ThiopheneFW 84.14, 38.1 % (m m) S.6.8 ThianaphtheneFW 134.20, 23.89 % (m/m) S.7. Hazards7.1 Consult current Occupational Safety HealthAdministra-tion (OSHA) regulations, supplier Ma
35、terial Safety Data Sheets,and local regulations for all materials used in this test method.7.2 High temperatures are used in this method; extra pre-caution should be exercised when working with flammablematerials near the pyrolysis furnace.8. Sampling8.1 General Requirements:8.1.1 Collect samples in
36、 accordance with Practice D4057 orD4177.8.1.2 To prevent the loss of volatile components, which maybe present in some samples, protect samples from excesstemperatures prior to testing. This can be done by storage in anice bath or refrigerator.8.1.3 Analyze samples as soon as possible to prevent loss
37、 ofsulfur components or contamination.8.1.4 Do not store samples in plastic containers, sincevolatile materials may diffuse through the walls of the con-tainer.8.1.5 Do not test samples stored in leaky containers. Discardand obtain a new sample if leaks in the containers are detected.9. Preparation
38、of Apparatus9.1 Place in service in accordance with the manufacturersinstructions. Typical instrument parameters are listed in Table1.9.2 Set gas flows and temperatures to the desired operatingconditions, in accordance with the manufacturers instructions.9.3 Ignite the flame photometric detector acc
39、ording to themanufacturers procedure.9.4 Prepare the sample introduction accessories, if required,according to the manufacturers instructions.9.5 Load a sulfur standard (see 6.5) into the injection valveor auto injector and inject into the gas chromatograph. Deter-mine the retention time of the SO2p
40、eak.9.6 Set-up a chromatographic analysis method according tothe manufacturers instructions.10. Calibration10.1 Choose which type of calibration method is required(mass/volume or mass/mass) and prepare a calibration standardfrom the stock solution (see 6.5.1 or 6.5.2) by volumetricdilution or mass d
41、ilution (see Note 3). The concentration of thecalibration standard should be approximately 50 % of thefull-scale concentration range of the test samples to be ana-lyzed.10.1.1 Load calibration standard into injection valve or autoinjector.10.1.2 Inject the calibration standard into the gas chromato-
42、graph. See Table 2 for recommended injection volumes.10.1.3 Analyze the calibration standard and obtain a chro-matogram. Calculate the relative response factor for the SO2peak:RFS5 Cn/AS! (3)where:RFS= relative response factor of SO2,Cn= sulfur concentration (mgS/kg) of the compound in thecalibratio
43、n mixture, andAS= peak area of the SO2component.11. Procedure11.1 Obtain a test sample using the procedure outlined inSection 8.11.2 Sample injection volumes can range from 0.1 L to1 L. Experience dictates the best sample volume. The injec-tion volume must be the same as used in the calibrationproce
44、dure. Typical injection volumes are listed in Table 2.11.3 Load the sample into the injection valve or autoinjector according to the manufacturers recommended proce-dure.11.4 Inject the sample into the chromatograph by startingthe chromatographic method, in accordance with the manufac-turers instruc
45、tions.11.5 Record concentration reading from gas chromatograph.See Fig. 1 for a typical chromatogram.11.6 Density values needed for the calculations are to betested using Test Methods D1298, D4052, or equivalent, at thetemperature at which the sample specimen was taken foranalysis by this test metho
46、d.12. Calculation12.1 If the analyzer was calibrated on a mass/volume basisthen calculate the sulfur content of the test sample in parts permillion by mass (mg/kg) as follows:sulfur, ppm g/g, mg/kg! 5 CSv/DS(4)where:CSv= concentration reading from analyzer (g/mL), andDS= density of sample (g/mL).12.
47、1.1 If the analyzer was calibrated on a mass/mass basisthen calculate the sulfur content of the test sample in parts permillion by mass (mg/kg) as follows:sulfur, ppm mg/g, mg/kg! 5 CSm!DC!/DS(5)TABLE 2 Suggested Injection VolumeSulfur, mg/kg Sample Size, LLess than 1 0.5 to 11 to 100 up to 0.5Great
48、er than 100 0.1 to 0.25D7041 163where:CSm= concentration reading from analyzer (mg/kg),DC= density of calibration standard (g/mL), andDS= density of sample (g/mL).13. Report13.1 Report the total sulfur concentration in parts permillion by mass (mg/kg) to the nearest 0.1 mgS/kg.14. Precision and Bias
49、4,514.1 PrecisionThe precision of this test method as deter-mined by statistical examination of interlaboratory test resultsare as follows:NOTE 5The following precision data were developed in a 2002interlaboratory cooperative test program. Nine participants analyzedsample sets of blind duplicates of 16 types of hydrocarbons andhydrocarbon-oxygenate blends. The sample set consisted of eight gasolinesamples and eight diesel samples. For the gasoline sample set, theconcentration range was approximately from 3 to 10
