1、Designation: D7620 10 (Reapproved 2015)Standard 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 d
2、esignation 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the
3、 determination of total sulfurin liquid hydrocarbon based fuel with a final boiling point of upto 450 C. It is applicable to analysis of natural, processed andfinal product materials containing sulfur in the range of4.0 mg kg to 830 mg kg (see Note 1).NOTE 1For liquid hydrocarbons containing less th
4、an 4.0 mg kg totalsulfur 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
5、. No other units of measurement 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-
6、bility of regulatory limitations 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, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD4052 Test Method
7、for Density, 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 ProductsD545
8、3 Test Method 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 Performance
9、D6300 Practice 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 termsuse
10、d in this 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 el
11、ementsthat 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). Waterproduce
12、d during the sample combustion is removed, asrequired, 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 astable state SO2
13、is 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 avoid1This test method is under the jurisdiction of ASTM Committee D02 onPetroleu
14、m Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved July 1, 2015. Published July 2015. Originally approvedin 2010. Last previous edition approved in 2010 as D7620 10. DOI:10.1520/D7620-10R15.2For referenced AS
15、TM 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 Conshoho
16、cken, PA 19428-2959. United States1exposing their body, especially their eyes, not only to directUV 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,
17、detection system and data handling are depicted.5. Significance and Use5.1 Some process catalysts used 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 co
18、mmercialtransportation fuels. This test method can be used to determinesulfur in process and downstream 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 wit
19、haccurate sulfur determination.6.2 Bound nitrogen at concentration greater than 150 mgN/kg can cause a 1 mg S/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 temperatur
20、esufficient to pyrolyze the entire sample (typically 1050 C 625 C) and oxidize sulfur to SO2.7.2 Combustion 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
21、to ensure completecombustion of the sample. Fig. 2 illustrates a typical combus-tion tube (Note 2).NOTE 2Other combustion tube configurations are acceptable ifprecision and accuracy are not degraded.7.3 Flow ControlThe apparatus shall be equipped withsuitable flow control apparatus capable of mainta
22、ining aconstant supply of air.7.4 Drier TubeThe apparatus shall be equipped with amechanism for the removal 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 p
23、ermeationdryer, that utilizes a selective capillary action for waterremoval.FIG. 1 Basic Block Diagram Describing Sulfur DeterminationFIG. 2 Typical Combustion TubeD7620 10 (2015)27.5 UV Fluorescence DetectorA quantitative detector ca-pable of measuring the energy emitted from the fluorescence ofsul
24、fur dioxide by UV light.7.6 Millilitre SyringeA disposable 1 mL syringe capableof accurately delivering a controlled 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 pene
25、tration andsample flow.7.7 Sample Inlet SystemAn automatic sample injectiondevice that is compatible with a disposable 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
26、 oxidation zoneat a controlled and repeatable rate.7.8 Strip Chart RecorderEquivalent electronic datalogger, integrator or recorder (optional).7.9 BalanceWith a precision of 60.01 mg (optional).8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in tests. Unless other
27、wise indicated, it is intended that allreagents shall conform to the specifications of the Committeeon Analytical 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 puri
28、ty to permit its use without lessening theaccuracy of the determination.8.2 AirFiltered (with a 2 m filter).8.3 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
29、 beused if precision and accuracy are not degraded.8.4.2 Apply the appropriate correction for chemical impu-rity.8.5 Sulfur Stock Solution1000 g S/mL. Prepare a stocksolution by accurately weighing 0.2624 g 6 0.013 g of thio-phene into a tared 100 mL volumetric flask. Dilute to volumewith selected s
30、olvent. This stock may be further diluted todesired sulfur concentration.8.5.1 Working standards should be reblended on a regularbasis depending upon frequency of use and age.NOTE 3Typically, stock solutions have a useful life of about 3 months.8.6 Quality Control (QC) SamplesPreferably, these arepo
31、rtions of one or more hydrocarbon materials that are stableand representative of the samples of interest. These QCsamples 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
32、 regulations for all materials usedin this test method.9.2 High temperature is employed in this test method.Exercise 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 whe
33、n performing thistest method.10. Sampling10.1 Collect the samples in accordance with Practice D4057or Practice D4177. 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
34、 with themanufacturers instructions.11.2 Typical instrument parameters are listed in Table 1.11.3 Prepare the sample introduction accessories, ifrequired, according to the manufacturers instructions.11.4 Adjust the instrument sensitivity and baseline stabilityand perform instrument blanking procedur
35、e following manu-facturers guidelines.12. Calibration12.1 Choose which type of calibration method is required(mass/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
36、in a different matrix than the sample, the calibration isset for the product derived from the weight/weight concentra-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-lat
37、ion are acceptable if precision and accuracy are not degraded.12.3 Based on anticipated sulfur concentration carefullyprepare a series of calibration standards that bracket theconcentrations of the samples being analyzed. Table 2 liststypical calibration curves. The calibration curve shall containat
38、 least three points, otherwise the number of standards usedper curve can vary.12.3.1 Prepare the instrument for calibration 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 wi
39、th a septum seal.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 LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United
40、States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 Typical Operating ConditionsFurnace Temperature 1050 CFurnace Pressure 28 kPaPhoto Multiplier Tube (PMT)Temperature40 CPMT Voltage 900 VOptics Purge Flow 80 mL min to 100 mL minD7620 10 (2015)
41、312.3.2 Install the millilitre syringe, enter the density of thecalibration standard and inject the standard into the analyzeraccording to the manufacturers instructions.12.3.3 Continue instrument calibration (by repeating 12.3.1through 12.3.2) to construct a calibration curve. The calibrationcurve
42、shall be linear and system performance shall be checkedeach day of use. See Section 16.13. Procedure13.1 Obtain a test specimen using the procedure describedin Section 10. The sulfur concentration in the test specimenshall be less than the concentration of the highest standard andgreater than the co
43、ncentration of the lowest standard used inthe calibration. If required, a dilution may be performed oneither a weight or volume basis.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)
44、Record themass of the test specimen and the total volume of the testspecimen and solvent.13.2 The injection rate shall be consistent 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 Determi
45、ne sulfur concentration in accordance with themanufacturers instructions.13.5 Cleaning and RecalibrationClean any coked orsooted parts per the manufacturers instructions. After anycleaning or adjustment, assemble and verify operation byanalyzing a calibration check standard (see Section 16).13.6 Den
46、sity values needed for the calculations are to beobtained using the Test Methods D1298, D4052, or equivalent,at the temperature at 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
47、/An(2)Cu5 RFS3 Au(3)where:RFS= response factor for sulfur,Cn= sulfur concentration in mg/kg in the calibrationmixture,An= counts 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 equa
48、l to or greater than 10 mg kg, reportthe sulfur result to the nearest mg/kg. For results less than10 mg kg, report the sulfur results to the nearest tenth of amg/kg. State that the results were obtained according to thisTest Method D7620.16. Quality Control16.1 Confirm the performance of the instrum
49、ent or the testprocedure by analyzing a quality control (QC) sample (8.6)after each calibration and at a frequency in accordance 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 sta
