1、Designation: D3701 01 (Reapproved 2012)D3701 17Standard Test Method forHydrogen Content of Aviation Turbine Fuels by LowResolution Nuclear Magnetic Resonance Spectrometry1This standard is issued under the fixed designation D3701; the number immediately following the designation indicates the year of
2、original 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.This standard has been approved for use by agencies of the U.S. Departm
3、ent of Defense.1. Scope Scope*1.1 This test method covers the determination of the hydrogen content of aviation turbine fuels.1.2 Use Test Methods D4808 or D7171 for the determination of hydrogen in other petroleum liquids.1.3 The values stated in SI units are to be regarded as standard. The preferr
4、ed units are mass percent hydrogen.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitat
5、ions prior to use. For a specific warning statement, see 6.1.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations i
6、ssuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1322 Test Method for Smoke Point of Kerosine and Aviation Turbine FuelD1740 Test Method for Luminometer Numbers of Aviation Turbine Fuels (Withdrawn 2006)3D4057 Practice for M
7、anual Sampling of Petroleum and Petroleum ProductsD4808 Test Methods for Hydrogen Content of Light Distillates, Middle Distillates, Gas Oils, and Residua by Low-ResolutionNuclear Magnetic Resonance SpectroscopyD7171 Test Method for Hydrogen Content of Middle Distillate Petroleum Products by Low-Reso
8、lution Pulsed Nuclear MagneticResonance Spectroscopy3. Summary of Test Method3.1 A sample of the material is compared in a continuous wave, low-resolution, nuclear magnetic resonance spectrometer witha reference standard sample of a pure hydrocarbon. The results from the integrator on the instrument
9、 are used as a means ofcomparing the theoretical hydrogen content of the standard with that of the sample, the result being expressed as the hydrogencontent (percent mass basis) in the sample.4. Significance and Use4.1 The combustion quality of aviation turbine fuel has traditionally been controlled
10、 in specifications by such tests as smokepoint (see Test Method D1322), smoke volatility index, aromatic content of luminometer number (see Test Method D1740).Evidence is accumulating that a better control of the quality may be obtained by limiting the minimum hydrogen content of thefuel.1 This test
11、 method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved April 15, 2012June 1, 2017. Published April 2012June 2017. Originally approved in 1978. Las
12、t previous edition approved in 20062012 asD370101(2006).D3701 01(2012). DOI: 10.1520/D3701-01R12.10.1520/D3701-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the
13、 standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous v
14、ersion. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes s
15、ection appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Existing methods allow the hydrogen content to be calculated from other parameters or determined by combustiontechniques. The method specifi
16、ed provides a quick, simple, and more precise alternative to these methods.D3701 1725. Apparatus5.1 Nuclear Magnetic Resonance Spectrometer4Alow-resolution continuous-wave instrument capable of measuring a nuclearmagnetic resonance of hydrogen atoms, and fitted with:5.1.1 Excitation and Detection Co
17、il, of suitable dimensions to contain the test cell.5.1.2 Electronic Unit, to control and monitor the magnet and coil and containing:5.1.2.1 Circuits, to control and adjust the radio frequency level and audio frequency gain.5.1.2.2 Integrating Counter, with variable time period in seconds.5.2 Condit
18、ioning BlockA block of aluminum alloy drilled with holes of sufficient size to accommodate the test cells with themean height of the sample being at least 20 mm 20 mm below the top of the conditioning block (see Fig. 1).5.3 Test CellsNessler-type tubes of approximately 100-mL100 mL capacity with a n
19、ominal external diameter of 34 mm34 mm and a nominal internal diameter of 31 mm 31 mm marked at a distance of approximately 51 mm 51 mm above the bottomof the tube by a ring around the circumference. The variation between the internal diameters of the test cells used for the sampleand reference mate
20、rial should not be greater than 60.5 mm.60.5 mm.NOTE 1To avoid potential difficulties with tightness when the test cell is introduced into the magnet coil, users are cautioned to avoid test cells thathave nominal external diameters that are greater than 34.2 mm.34.2 mm.5.4 Polytetrafluoroethylene (P
21、TFE) Plugs for Closing Test CellsPlugs as shown in Fig. 1 made from pure PTFE and a tightfit in the test cells.5.5 Insertion RodA metal rod with a threaded end as shown in Fig. 1 for inserting and removing PTFE plugs from test cells.5.6 Analytical BalanceTop pan type, capable of weighing the test ce
22、lls in an upright position to an accuracy of 60.01g.60.01 g.4 This test method has been written around the Newport Analyzer Mark IIIF (Oxford Analytical Instruments, Ltd., Oxford, England) and the details of the test methodshould be read in conjunction with the manufacturers handbook.This particular
23、 instrument was the only instrument available when the precision program was carried out.Any similar instrument would be accepted into the above methodprovided the new instrument was adequately correlated and proved to be statistically similar. If you are aware of alternative suppliers, please provi
24、de this information toASTMInternational Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which you may attend.The NewportAnalyzer Mark IIIF is no longer in production and was replaced by the manufacturer with the Newport 4000. The N
25、ewport 4000 model instrument has beendemonstrated to provide equivalent results to those obtained with the Mark III models which were used to generate the precision data. As of the mid-1990s however, theNewport 4000 instrument is no longer being manufactured by the vendor. No newer models are curren
26、tly being manufactured as replacements for the Newport 4000instrument.NOTE 1All dimensions are nominal values in millimetres, unless the tolerance limit is specified.FIG. 1 Hydrogen Content of Aviation Turbine FuelsD3701 1736. Materials6.1 Reference StandardDodecane, 99 99 % by mass % minimum purity
27、 (WarningFlammable).7. Sampling7.1 Take a homogenous sample in accordance with Practice D4057.8. Preparation of Apparatus8.1 Read the following instructions in conjunction with the manufacturers handbook. Preparation of the instrument is notcritical but take care to prevent rapid temperature fluctua
28、tions of the instrument and the conditioning block, for example, avoidthem from direct sunlight or from drafts.8.2 The results obtained during the use of the equipment are susceptible to error arising from changes in the magneticenvironment. Exercise care to ensure that there is a minimum of magneti
29、c material in the immediate vicinity of the equipment andthat this be kept constant throughout the course of a series of determinations.8.3 Set the instrument controls to the following conditions:NOTE 2On new NMR instruments with variable gates the gate should be set at 1.5 gauss to comply with nonv
30、ariable gate instruments.Radio frequency level 20 AAudio frequency gain 500 on dialIntegration time 128 s8.4 Switch on the main supply to the spectrometer and allow it to warm up for at least 1 h.1 h.8.5 Place a test cell containing sample in the coil and adjust the tuning of the instrument until th
31、e two resonance curves on theoscilloscope are coincident. This setting may need to be readjusted during determinations.8.6 Remove the test cell from the coil and observe that the signal readout is now 0 6 3 digits. This should be checkedperiodically during the series of tests to ensure that no conta
32、mination of the coil has occurred.9. Preparation of Samples and Standard9.1 Take a clean, dry test cell and PTFE plug and weigh them together to the nearest 0.01 g 0.01 g and record the mass. Add3030 mL 6 1 mL 1 mL of the reference standard to the tube, taking extreme care to prevent splashing the l
33、iquid above the lineinscribed on the tube. The use of a pipet is recommended for this operation.9.2 Using the insertion rod, push the PTFE plug into the tube until it is just above the liquid-surface, keeping the tube upright.A gentle twisting of the plug as it is inserted will aid the escape of air
34、 from the test cell and normally ensure that the lip of theplug is turned up around the entire circumference. Take care to ensure that this is so, as a plug that is not properly inserted willallow rapid sample evaporation and give rise to change in the results obtained.NOTE 3The insertion of the PTF
35、E plug can be facilitated by inserting a length of thin (less than 0.2 mm 0.2 mm diameter) copper wire down theinside surface of the disc until it is approximately 38 mm 38 mm from the graduation mark and then pushing the PTFE plug down past the wire whichis then removed.9.3 The bottom rim of the pl
36、ug should be at or slightly below the 51-mm51 mm mark on the test cell. Unscrew the insertionrod carefully without disturbing the plug.9.4 Place the reference standard in the sample conditioning block.9.5 Repeat the procedure outlined in 9.1 9.4 using the material to be tested.10. Procedure10.1 Leav
37、e the sample and reference standard in the conditioning block for at least 0.5 h 0.5 h to ensure they reach uniformtemperature, that is room temperature, before measurements are made.10.2 Read the following instructions in conjunction with the procedure provided in the manufacturers handbook for ana
38、lyzingsamples. Specific steps may vary with instrument manufacturer and model. In cases where the manufacturers instructions differfrom the following steps, follow the manufacturers instructions.10.3 Take the reference standard and place it carefully in the coil. When fully entered the top of the te
39、st cell should be just abovethe cover of the spectrometer unit.10.4 Check that the peaks on the oscilloscope are coincident and if this is not so, adjust the tuning until they are.10.5 When the reference standard has been in the magnet unit for at least 3 s, 3 s, push the reset button.NOTE 4It is im
40、portant that a delay of this magnitude be allowed before commencing measurement in order that the hydrogen nuclei are fully polarizedin the magnetic field.10.6 After a count time of 128 s 128 s the digital display will stop at its final value. Record the integrator counts and push thereset button ag
41、ain and record the second reading.D3701 17410.7 Weigh the cell and contents and record the total mass.10.8 Replace the reference standard in the conditioning block and make similar duplicate readings on the sample to be tested.NOTE 5Measurements will be altered by temperature variations in the sampl
42、e and reference standard so these must be returned to the conditioningblock when measurements are not being made.NOTE 6The determined hydrogen content will be affected by any instrument drift, slight variations in temperature between the sample and referencestandard and loss of sample or reference s
43、tandard, or both, due to evaporation. Therefore when a series of results are to be determined, sample andreference standard should be measured, weighed and calculated as pairs. When the mass change of the reference standard is greater than 0.01 g 0.01 gbetween consecutive weighings, the cause of thi
44、s should be investigated and corrected. Losses are usually due to poor fitting of the PTFE plug while gainswill probably be due to contamination of the coil.11. Calculation11.1 For each sample and reference standard, subtract the mass of the test cell and PTFE plug from the total mass of the testcel
45、l determined in 10.7.Hydrogen content,mass%5 STSR3MRMT315.39 (1)where: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
46、 to the nearest 0.01 mass %.0.01 % by mass.13. Precision and Bias513.1 The precision of the method as obtained by statistical examination of interlaboratory test results is as follows:13.1.1 RepeatabilityThe difference between successive test results obtained by the same operator with the same appar
47、atusunder constant operating conditions on identical test material would, in the long run, in the normal and correct operation of thetest method exceed the following value only in one case in twenty:0.09 mass% (2)13.1.2 ReproducibilityThe difference between two single and independent results obtaine
48、d by different operators working indifferent laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceedthe following value only in one case in twenty:0.11 mass% (3)13.2 BiasA 1977 research report indicated that the hydrogen content d
49、etermined by this test method is biased high withrespect to the expected value for pure known materials.14. Keywords14.1 aviation turbine fuel; hydrogen; nuclear magnetic resonanceSUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes to this standard since the last issue(D3701 01 (2012) that may impact the use of this standard. (Approved June 1, 2017.)(1) An alternative method for this analysis is given in subsection 1.2; added Test Method D7171 to Referenced Documents.5 Supporting data have been filed at ASTM Inte
