1、Designation: D 3701 01 (Reapproved 2006)Designation: 338/98An American National StandardStandard Test Method forHydrogen Content of Aviation Turbine Fuels by LowResolution Nuclear Magnetic Resonance Spectrometry1This standard is issued under the fixed designation D 3701; the number immediately follo
2、wing the designation 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.This standard has been appro
3、ved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the determination of the hydro-gen content of aviation turbine fuels.1.2 Use Test Methods D 4808 for the determination ofhydrogen in other petroleum liquids.1.3 The values stated in SI units are to be regarded
4、asstandard. The preferred units are mass percent hydrogen.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-bil
5、ity of regulatory limitations prior to use. For a specificprecautionary statement, see 6.1.2. Referenced Documents2.1 ASTM Standards:2D 1322 Test Method for Smoke Point of Kerosine andAviation Turbine FuelD 1740 Test Method for Luminometer Numbers of AviationTurbine FuelsD 4057 Practice for Manual S
6、ampling of Petroleum andPetroleum ProductsD 4808 Test Methods for Hydrogen Content of Light Dis-tillates, Middle Distillates, Gas Oils, and Residua byLow-Resolution Nuclear Magnetic Resonance Spectros-copy3. Summary of Test Method3.1 A sample of the material is compared in a continuouswave, low-reso
7、lution, nuclear magnetic resonance spectrom-eter with a reference standard sample of a pure hydrocarbon.The results from the integrator on the instrument are used as ameans of comparing the theoretical hydrogen content of thestandard with that of the sample, the result being expressed asthe hydrogen
8、 content (percent mass basis) in the sample.4. Significance and Use4.1 The combustion quality of aviation turbine fuel hastraditionally been controlled in specifications by such tests assmoke point (see Test Method D 1322), smoke volatility index,aromatic content of luminometer number (see Test Meth
9、odD 1740). Evidence is accumulating that a better control of thequality may be obtained by limiting the minimum hydrogencontent of the fuel.4.2 Existing methods allow the hydrogen content to becalculated from other parameters or determined by combustiontechniques. The method specified provides a qui
10、ck, simple, andmore precise alternative to these methods.5. Apparatus5.1 Nuclear Magnetic Resonance Spectrometer3A low-resolution continuous-wave instrument capable of measuring anuclear magnetic resonance of hydrogen atoms, and fitted with:5.1.1 Excitation and Detection Coil, of suitable dimensions
11、to contain the test cell.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved May 1, 2006. Published June 2006. Originallyapproved in 1978. Last prev
12、ious edition approved in 2001 as D 3701 01.2For referenced ASTM 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.3This test method
13、has been written around the Newport Analyzer Mark IIIF(Oxford Analytical Instruments, Ltd., Oxford, England) and the details of the testmethod should be read in conjunction with the manufacturers handbook.This particular instrument was the only instrument available when the precisionprogram was carr
14、ied out. Any similar instrument would be accepted into the abovemethod provided the new instrument was adequately correlated and proved to bestatistically similar. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receive
15、careful consideration at a meeting of the responsible technical committee,1whichyou may attend.The Newport Analyzer Mark IIIF is no longer in production and was replaced bythe manufacturer with the Newport 4000. The Newport 4000 model instrument hasbeen demonstrated to provide equivalent results to
16、those obtained with the Mark IIImodels which were used to generate the precision data. As of the mid-1990showever, the Newport 4000 instrument is no longer being manufactured by thevendor. No newer models are currently being manufactured as replacements for theNewport 4000 instrument.1*A Summary of
17、Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.2 Electronic Unit, to control and monitor the magnet andcoil and containing:5.1.2.1 Circuits, to control and adjust the radio freq
18、uencylevel and audio frequency gain.5.1.2.2 Integrating Counter, with variable time period inseconds.5.2 Conditioning BlockA block of aluminum alloy drilledwith holes of sufficient size to accommodate the test cells withthe mean height of the sample being at least 20 mm below thetop of the condition
19、ing block (see Fig. 1).5.3 Test CellsNessler-type tubes of approximately100-mL capacity with a nominal external diameter of 34 mmand a nominal internal diameter of 31 mm marked at a distanceof approximately 51 mm above the bottom of the tube by a ringaround the circumference. The variation between t
20、he internaldiameters of the test cells used for the sample and referencematerial should not be greater than 60.5 mm.NOTE 1To avoid potential difficulties with tightness when the test cellis introduced into the magnet coil, users are cautioned to avoid test cellsthat have nominal external diameters t
21、hat are greater than 34.2 mm.5.4 Polytetrafluoroethylene (PTFE) Plugs for Closing TestCellsPlugs as shown in Fig. 1 made from pure PTFE and atight fit in the test cells.5.5 Insertion RodA metal rod with a threaded end asshown in Fig. 1 for inserting and removing PTFE plugs fromtest cells.5.6 Analyti
22、cal BalanceTop pan type, capable of weighingthe test cells in an upright position to an accuracy of 60.01 g.6. Materials6.1 Reference StandardDodecane, 99 mass % minimumpurity (WarningFlammable).7. Sampling7.1 Take a homogenous sample in accordance with PracticeD 4057.8. Preparation of Apparatus8.1
23、Read the following instructions in conjunction with themanufacturers handbook. Preparation of the instrument is notcritical but take care to prevent rapid temperature fluctuationsof the instrument and the conditioning block, for example,avoid them from direct sunlight or from drafts.8.2 The results
24、obtained during the use of the equipment aresusceptible to error arising from changes in the magneticenvironment. Exercise care to ensure that there is a minimumof magnetic material in the immediate vicinity of the equip-ment and that this be kept constant throughout the course of aseries of determi
25、nations.8.3 Set the instrument controls to the following conditions:NOTE 2On new NMR instruments with variable gates the gate shouldbe set at 1.5 gauss to comply with nonvariable gate instruments.Radio frequency level 20 AAudio frequency gain 500 on dialIntegration time 128 s8.4 Switch on the main s
26、upply to the spectrometer and allowit to warm up for at least 1 h.8.5 Place a test cell containing sample in the coil and adjustthe tuning of the instrument until the two resonance curves onthe oscilloscope are coincident. This setting may need to bereadjusted during determinations.8.6 Remove the te
27、st cell from the coil and observe that thesignal readout is now 0 6 3 digits. This should be checkedperiodically during the series of tests to ensure that nocontamination of the coil has occurred.NOTEAll dimensions are nominal values in millimetres, unless the tolerance limit is specifiedFIG. 1 Hydr
28、ogen Content of Aviation Turbine FuelsD 3701 01 (2006)29. Preparation of Samples and Standard9.1 Take a clean, dry test cell and PTFE plug and weighthem together to the nearest 0.01 g and record the mass.Add 306 1 mL of the reference standard to the tube, taking extremecare to prevent splashing the
29、liquid above the line inscribed onthe tube. The use of a pipet is recommended for this operation.9.2 Using the insertion rod, push the PTFE plug into thetube until it is just above the liquid-surface, keeping the tubeupright. A gentle twisting of the plug as it is inserted will aidthe escape of air
30、from the test cell and normally ensure that thelip of the plug is turned up around the entire circumference.Take care to ensure that this is so, as a plug that is not properlyinserted will allow rapid sample evaporation and give rise tochange in the results obtained.NOTE 3The insertion of the PTFE p
31、lug can be facilitated by insertinga length of thin (less than 0.2 mm diameter) copper wire down the insidesurface of the disc until it is approximately 38 mm from the graduationmark and then pushing the PTFE plug down past the wire which is thenremoved.9.3 The bottom rim of the plug should be at or
32、 slightlybelow the 51-mm mark on the test cell. Unscrew the insertionrod carefully without disturbing the plug.9.4 Place the reference standard in the sample conditioningblock.9.5 Repeat the procedure outlined in 9.1-9.4 using thematerial to be tested.10. Procedure10.1 Leave the sample and reference
33、 standard in the condi-tioning block for at least 0.5 h to ensure they reach uniformtemperature, that is room temperature, before measurementsare made.10.2 Read the following instructions in conjunction with theprocedure provided in the manufacturers handbook for ana-lyzing samples. Specific steps m
34、ay vary with instrumentmanufacturer and model. In cases where the manufacturersinstructions differ from the following steps, follow the manu-facturers instructions.10.3 Take the reference standard and place it carefully in thecoil. When fully entered the top of the test cell should be justabove the
35、cover of the spectrometer unit.10.4 Check that the peaks on the oscilloscope are coincidentand if this is not so, adjust the tuning until they are.10.5 When the reference standard has been in the magnetunit for at least 3 s, push the reset button.NOTE 4It is important that a delay of this magnitude
36、be allowedbefore commencing measurement in order that the hydrogen nuclei arefully polarized in the magnetic field.10.6 After a count time of 128 s the digital display will stopat its final value. Record the integrator counts and push thereset button again and record the second reading.10.7 Weigh th
37、e cell and contents and record the total mass.10.8 Replace the reference standard in the conditioningblock and make similar duplicate readings on the sample to betested.NOTE 5Measurements will be altered by temperature variations in thesample and reference standard so these must be returned to the c
38、ondition-ing block when measurements are not being made.NOTE 6The determined hydrogen content will be affected by anyinstrument drift, slight variations in temperature between the sample andreference standard and loss of sample or reference standard, or both, dueto evaporation. Therefore when a seri
39、es of results are to be determined,sample and reference standard should be measured, weighed and calcu-lated as pairs. When the mass change of the reference standard is greaterthan 0.01 g between consecutive weighings, the cause of this should beinvestigated and corrected. Losses are usually due to
40、poor fitting of thePTFE plug while gains will probably be due to contamination of the coil.11. Calculation11.1 For each sample and reference standard, subtract themass of the test cell and PTFE plug from the total mass of thetest cell determined in 10.7.Hydrogen content, mass % 5STSR3MRMT3 15.39 (1)
41、where:ST= mean of integrator counts on sample under test,SR= mean of integrator counts on reference standard,MR= mass of reference sample, andMT= mass of sample under test12. Report12.1 Report the mass percent hydrogen content to thenearest 0.01 mass %.13. Precision and Bias413.1 The precision of th
42、e method as obtained by statisticalexamination of interlaboratory test results is as follows:13.1.1 RepeatabilityThe difference between successivetest results obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial would, in the long run, in
43、 the normal and correctoperation of the test method exceed the following value only inone case in twenty:0.09 mass % (2)13.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would,
44、inthe long run, in the normal and correct operation of the testmethod exceed the following value only in one case in twenty:0.11 mass %(3)13.2 BiasA 1977 research report indicated that the hydro-gen content determined by this test method is biased high withrespect to the expected value for pure know
45、n materials.14. Keywords14.1 aviation turbine fuel; hydrogen; nuclear magneticresonance4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D02-1186.D 3701 01 (2006)3SUMMARY OF CHANGESSubcommittee D02.03 has identified the location
46、of selected changes to this standard since the last issue,D 3701 99a, that may impact the use of this standard.(1) Updated information in Footnote 3 to reflect that theNewport 4000 instrument is no longer being manufacturedcurrently for use in the test.(2) Inserted a new paragraph 10.2 to instruct t
47、he user to followthe instructions from the vendor in the Procedure section,similar to instructions already in the method in Section 8(Preparation of Apparatus) that refers the user to the manufac-turers handbook.ASTM International takes no position respecting the validity of any patent rights assert
48、ed in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by t
49、he responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This
