1、Designation: D7620 10Standard Test Method forDetermination of Total Sulfur in Liquid Hydrocarbon BasedFuels by Continuous Injection, Air Oxidation and UltravioletFluorescence Detection1This standard is issued under the fixed designation D7620; the number immediately following the designation indicat
2、es 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. Scope1.1 This test method covers the determination of
3、total sulfurin liquid hydrocarbon based fuel with a final boiling point of upto 450C. It is applicable to analysis of natural, processed andfinal product materials containing sulfur in the range of 4.0 to830 mg/kg (see Note 1).NOTE 1 For liquid hydrocarbons containing less than 4.0 mg/kg totalsulfur
4、 or more than 830 mg/kg total sulfur, Test Method D5453 may bemore appropriate.1.2 This test method is applicable for total sulfur determi-nation in liquid hydrocarbons containing less than 0.35%(m/m) halogen(s).1.3 The values stated in SI units are to be regarded asstandard. No other units of measu
5、rement are included in thisstandard.1.4 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 and health practices and determine the applica-bility of regulatory limi
6、tations prior to use. For specific hazardstatements, see 4.1, 8.3, and Section 9.2. Referenced Documents2.1 ASTM Standards:2D1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer MethodD4052 Test Method for Dens
7、ity, Relative Density, and APIGravity of Liquids by Digital Density MeterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology Relating to Petroleum, PetroleumProducts, and LubricantsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD5453 Test M
8、ethod for Determination of Total Sulfur inLight Hydrocarbons, Spark Ignition Engine Fuel, DieselEngine Fuel, and Engine Oil by Ultraviolet FluorescenceD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6300 Pr
9、actice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories3. Terminology3.1 Definitions:3.1.1 See Terminology D4175 for definitions of other termsused in thi
10、s test method.3.1.2 oxidative pyrolysis, nprocess in which a sampleundergoes complete combustion in an appropriate oxygencontaining environment at a sufficiently elevated temperature.3.1.2.1 DiscussionOrganic compounds pyrolytically oxi-dize to carbon dioxide and water and oxides of other elementsth
11、at are in the sample.4. Summary of Test Method4.1 A small, very controlled flow of hydrocarbon sample iscontinuously injected during measurement. It is introduced viaa syringe into a high temperature combustion tube containingair where sulfur is oxidized to sulfur dioxide (SO2). Waterproduced during
12、 the sample combustion is removed, as re-quired, and the sample combustion gases are next exposed toultraviolet (UV) light. The SO2absorbs the energy from theUV light and is converted to excited sulfur dioxide (SO2*).Fluorescence emitted from the excited SO2* as it returns to a1This test method is u
13、nder the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Sept. 1, 2010. Published September 2010.DOI:10.1520/D762010.2For referenced ASTM standards, visit the ASTM website, ww
14、w.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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.stab
15、le state SO2is detected by a photomultiplier tube and theresulting signal is a measure of the sulfur contained in thesample. (WarningExposure to excessive quantities of ultra-violet light is injurious to health. The operator shall avoidexposing their body, especially their eyes, not only to directUV
16、 light but also to secondary or scattered radiation that ispresent.)4.2 Fig. 1 illustrates a basic block diagram describing sulfurdetermination. Sample collection and conditioning, sampleintroduction, detection system and data handling are depicted.5. Significance and Use5.1 Some process catalysts u
17、sed in refining can be poisonedwhen trace amounts of sulfur bearing materials are contained inthe feedstocks. There are also government regulations as tohow much sulfur is permitted to be present in commercialtransportation fuels. This test method can be used to determinesulfur in process and downst
18、ream distribution streams. It canalso be used for purposes of screening and quality control offinished hydrocarbon fuel products.6. Interferences6.1 Halogens above 0.35 % (mass/mass) will interfere withaccurate sulfur determination.6.2 Bound nitrogen at concentration greater than 150 mgN/kg can caus
19、ea1mgS/kg positive bias.6.3 Excessive moisture produced during the combustionstep will interfere if not removed prior to the detector.7. Apparatus7.1 FurnaceAn electric furnace held at a temperaturesufficient to pyrolyze the entire sample (typically 1050 625C) and oxidize sulfur to SO2.7.2 Combustio
20、n TubeA quartz combustion tube con-structed to allow the direct injection of a continuous flow ofsample into the heated oxidation zone of the furnace. Theoxidation section shall be large enough to ensure completecombustion of the sample. Fig. 2 illustrates a typical combus-tion tube (Note 2).NOTE 2O
21、ther combustion tube configurations are acceptable if pre-cision and accuracy are not degraded.7.3 Flow ControlThe apparatus shall be equipped withsuitable flow control apparatus capable of maintaining aconstant supply of air.7.4 Drier TubeThe apparatus shall be equipped with amechanism for the remo
22、val of excessive water vapor. Theoxidation reaction produces water vapor which must be elimi-nated prior to measurement by the detector. This may beaccomplished with a membrane drying tube, or a permeationdryer, that utilizes a selective capillary action for waterremoval.FIG. 1 Basic Block Diagram D
23、escribing Sulfur DeterminationFIG. 2 Typical Combustion TubeD7620 1027.5 UV Fluorescence DetectorA quantitative detector ca-pable of measuring the energy emitted from the fluorescence ofsulfur dioxide by UV light.7.6 Millilitre SyringeA disposable 1 mL syringe capableof accurately delivering a contr
24、olled and constant flow ofcalibration and sample materials. The syringe shall accommo-date a disposable tip to aid the filling of the syringe and adisposable septum seal to accommodate penetration andsample flow.7.7 Sample Inlet SystemAn automatic sample injectiondevice that is compatible with a dis
25、posable 1 mL syringe isrequired. The injector shall allow the introduction of anappropriate continuous flow of sample into a combustion tubecarrier stream, which directs the sample into the oxidation zoneat a controlled and repeatable rate.7.8 Strip Chart RecorderEquivalent electronic data log-ger,
26、integrator or recorder (optional).7.9 BalanceWith a precision of 6 0.01 mg (optional).8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committeeon Analy
27、tical Reagents of the American Chemical Society,where such specifications are 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.8.2 AirFiltered (witha2mfilter).8.3
28、Iso-octane, Toluene, XylenesReagent grade.(WarningOrganic solvents are flammable.)8.4 ThiopheneFW84.14, Sulfur content 38.10 % (m/m).8.4.1 Other sources of sulfur and diluent materials may beused if precision and accuracy are not degraded.8.4.2 Apply the appropriate correction for chemical impu-rity
29、.8.5 Sulfur Stock Solution1000 g S/mL. Prepare a stocksolution by accurately weighing 0.2624 6 0.013 g of thiopheneinto a tared 100 mL volumetric flask. Dilute to volume withselected solvent. This stock may be further diluted to desiredsulfur concentration.8.5.1 Working standards should be reblended
30、 on a regularbasis depending upon frequency of use and age.NOTE 3Typically, stock solutions have a useful life of about 3months.8.6 Quality Control (QC) SamplesPreferably, these areportions of one or more hydrocarbon materials that are stableand representative of the samples of interest. These QCsam
31、ples may be used to check the validity of the testingprocess as described in Section 16.9. Hazards9.1 Consult current OSHA regulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.9.2 High temperature is employed in this test method.Exercise
32、extra care when using flammable materials near theoxidative pyrolysis furnace.9.3 Due to the types of samples analyzed in this test method,chemical resistant gloves should be worn when performing thistest method.10. Sampling10.1 Collect the samples in accordance with Practice D4057or Practice D4177.
33、 To preserve volatile components which arein some samples, do not uncover samples any longer thannecessary.11. Preparation of Apparatus11.1 Place the analyzer in service in accordance with themanufacturers instructions.11.2 Typical instrument parameters are listed in Table 1.11.3 Prepare the sample
34、introduction accessories, if re-quired, according to the manufacturers instructions.11.4 Adjust the instrument sensitivity and baseline stabilityand perform instrument blanking procedure following manu-facturers guidelines.12. Calibration12.1 Choose which type of calibration method is required(mass/
35、volume or mass/mass), and prepare a calibration stan-dard from the stock solution (8.5) by volume or mass dilution.12.2 If a mass/mass analysis is being done with a calibrationstandard in a different matrix than the sample, the calibration isset for the product derived from the weight/weight concent
36、ra-tion estimate (see Eq 1 in 14.1 and Note 4).NOTE 4Apparatus capable of accepting a fixed or variable densityinput and utilizing an automatic density compensation and result calcu-lation are acceptable if precision and accuracy are not degraded.12.3 Based on anticipated sulfur concentration carefu
37、llyprepare a series of calibration standards that bracket theconcentrations of the samples being analyzed. Table 2 liststypical calibration curves. The calibration curve shall containat least three points, otherwise the number of standards usedper curve can vary.12.3.1 Prepare the instrument for cal
38、ibration and fill themillilitre syringe to approximately the 0.75 mL mark withsample prior to analysis. Eliminate any bubbles that are presentin the liquid column and cap the syringe with a septum seal.12.3.2 Install the millilitre syringe, enter the density of thecalibration standard and inject the
39、 standard into the analyzeraccording to the manufacturers instructions.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChe
40、micals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 Typical Operating ConditionsFurnace Temperature 1050CFurnace Pressure 28 kPaPhoto Multiplier Tube (PMT) Temperature 40CPMT Voltage 900 VOp
41、tics Purge Flow 80 to 100 mL/minD7620 10312.3.3 Continue instrument calibration (by repeating 12.3.1through 12.3.2) to construct a calibration curve. The calibrationcurve shall be linear and system performance shall be checkedeach day of use. See Section 16.13. Procedure13.1 Obtain a test specimen u
42、sing the procedure describedin Section 10. The sulfur concentration in the test specimenshall be less than the concentration of the highest standard andgreater than the concentration of the lowest standard used inthe calibration. If required, a dilution may be performed oneither a weight or volume b
43、asis.13.1.1 Gravimetric Dilution (mass/mass)Record the massof the test specimen and the total mass of the test specimen andsolvent.13.1.2 Volumetric Dilution (mass/volume)Record themass of the test specimen and the total volume of the testspecimen and solvent.13.2 The injection rate shall be consist
44、ent with that used inthe calibration procedure (See Section 12).13.3 Measure the response for the test specimen solutionusing the procedures described in 12.3.13.4 Determine sulfur concentration in accordance with themanufacturers instructions.13.5 Cleaning and RecalibrationClean any coked orsooted
45、parts per the manufacturers instructions. After anycleaning or adjustment, assemble and verify operation byanalyzing a calibration check standard (see Section 16).13.6 Density values needed for the calculations are to beobtained using the Test Methods D1298, D4052, or equivalent,at the temperature a
46、t which the sample specimen was taken foranalysis by this test method.14. Calculations14.1g Sulfurg Solvent3Density of solventDensity of Sample5g Sulfurg Solvent(1)RFS5 Cn/ An(2)Cu5 RFS3 Au(3)where:RFS= response factor for sulfur,Cn= sulfur concentration in mg/kg in the calibrationmixture,An= counts
47、 from the detector from calibration mixture,Cu= sulfur concentration in mg/kg of the sample, andAu= counts from the detector from the sample.15. Report15.1 For results equal to or greater than 10 mg/kg, report thesulfur result to the nearest mg/kg. For results less than 10mg/kg, report the sulfur re
48、sults to the nearest tenth of a mg/kg.State that the results were obtained according to this TestMethod D7620.16. Quality Control16.1 Confirm the performance of the instrument or the testprocedure by analyzing a quality control (QC) sample (8.6)after each calibration and at a frequency in accordance
49、 withlocal site requirements.16.1.1 When QC/Quality Assurance (QA) protocols arealready established in the testing facility, these may be usedwhen they confirm the reliability of the test result.16.1.2 When there is no QC/QA protocol established in thetesting facility, Appendix X1 may be used as the QC/QAsystem.17. Precision and Bias417.1 PrecisionThe precision of this test method as deter-mined by statistical examination of interlaboratory test resultsusing Practice D6300 is as follows.NOTE 5The following precision data were developed in
