ASTM D4808-2001(2012) Standard Test Methods for Hydrogen Content of Light Distillates Middle Distillates Gas Oils and Residua by Low-Resolution Nuclear Magnetic Resonance Spectrosc.pdf

1、Designation: D4808 01 (Reapproved 2012)Standard Test Methods forHydrogen Content of Light Distillates, Middle Distillates,Gas Oils, and Residua by Low-Resolution Nuclear MagneticResonance Spectroscopy1This standard is issued under the fixed designation D4808; the number immediately following the des

2、ignation 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.This standard has been approved for use b

3、y agencies of the Department of Defense.1. Scope1.1 These test methods cover the determination of thehydrogen content of petroleum products ranging from atmo-spheric distillates to vacuum residua using a continuous wave,low-resolution nuclear magnetic resonance spectrometer. (TestMethod D3701 is the

4、 preferred method for determining thehydrogen content of aviation turbine fuels using nuclearmagnetic resonance spectroscopy.)1.2 Three test methods are included here that account for thespecial characteristics of different petroleum products andapply to the following distillation ranges:Test Method

5、 Petroleum Products Boiling Range, C (F)(approximate)A Light Distillates 15260 (60500)B Middle Distillates 200370 (400700)Gas Oils 370510 (700950)C Residua 510+ (950+ )1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard. The pre

6、ferred units are mass %.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 limitations prio

7、r to use. For specificwarning statements, see Sections 6.2 and 6.4.2. Referenced Documents2.1 ASTM Standards:2D3701 Test Method for Hydrogen Content of AviationTurbine Fuels by Low Resolution Nuclear Magnetic Reso-nance SpectrometryD4057 Practice for Manual Sampling of Petroleum andPetroleum Product

8、sD5291 Test Methods for Instrumental Determination ofCarbon, Hydrogen, and Nitrogen in Petroleum Productsand Lubricants3. Summary of Test Methods3.1 A test specimen is compared in a continuous wave,low-resolution nuclear magnetic resonance (NMR) spectrom-eter with a reference standard sample. The sp

9、ectrometerrecords in a nondestructive fashion the absolute concentrationof hydrogen atoms in the reference standard and test sample.The absolute hydrogen concentrations reported by the integra-tor on the NMR instrument for the standard and test specimensare used as a means of comparing the theoretic

10、al hydrogencontent of the standard with that of the sample, the result beingexpressed as the hydrogen content (on a mass % basis) of thesample.3.2 To ensure an accurate measure of the absolute hydrogencontent of the reference standard and sample, it is necessary toensure that the measured hydrogen i

11、ntegrator counts are alwaysdirectly proportional to the absolute hydrogen content of thestandard and sample.3.3 Undercounting of the reference standard with respect tothe sample is avoided in Test Methods B and C by dilution ofthe standard with a relaxation reagent solution. Undercountingof highly v

12、iscous or solid test samples is avoided by dissolvingthe sample in a non-hydrogen containing solvent, whichensures that all of the weighed sample is in a fluid andhomogeneous solution at the time of measurement.An elevatedsample temperature at the time of measurement also ensures ahomogeneous liquid

13、-phase sample.4. Significance and Use4.1 The hydrogen content represents a fundamental qualityof a petroleum product that has been correlated with many ofthe performance characteristics of that product.4.2 This test method provides a simple and more precisealternative to existing test methods, speci

14、fically combustiontechniques (Test Methods D5291) for determining the hydro-gen content on a range of petroleum products.1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and are the direct responsibility of Subcommit-tee D02.03 on Elemental Ana

15、lysis.Current edition approved April 15, 2012. Published May 2012. Originallyapproved in 1988. Last previous edition approved in 2006 as D480801(2006).DOI: 10.1520/D4808-01R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. Fo

16、r 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.5. ApparatusNOTE 1This test method has been written around the Newport

17、Analyzer Mark IIIF or its replacement version, the Newport 4000 (OxfordAnalytical Instruments, Ltd., Oxford, England), and the details of the testmethod are to be read in conjunction with the manufacturers handbook.These instruments have demonstrated statistically indistinguishable per-formance in t

18、hese standard test methods and in Test Method D3701. Anysimilar instrument is acceptable, provided that the new instrument isadequately correlated and proved to be statistically similar. As of themid-1990s, however, the Newport 4000 instrument is no longer beingmanufactured by the vendor. No newer m

19、odels are currently beingmanufactured as replacements for the Newport 4000 instrument.5.1 Nuclear Magnetic Resonance Spectrometer:5.1.1 Alow-resolution, continuous wave instrument capableof measuring a nuclear magnetic resonance signal due tohydrogen atoms in the sample and includes an excitation an

20、ddetection coil of suitable dimensions to contain the test cell; anelectronic unit, to control and monitor the magnet and coil, andcontaining: circuits, to control and adjust the radio-frequencylevel and audio-frequency gain; and integrating counter, withvariable time period in seconds.5.1.2 Test Me

21、thods B and C also require that the instrumenthas the ability to equilibrate samples within the probe at anelevated temperature (50C).5.2 Conditioning BlockAblock of aluminum alloy drilledwith holes of sufficient size to accommodate the test cells withthe mean height of the sample being at least 20

22、mm below thetop of the conditioning block, capable of holding the sample atthe given test temperature (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 51 mm above the

23、 bottom of the tube by a ring around thecircumference. The variation between the internal diameters ofthe test cells used for the sample and reference material shouldnot be greater than 60.5 mm.NOTE 2To avoid potential difficulties with tightness when the test cellis introduced into the magnet coil,

24、 users are cautioned to avoid test cellsthat have nominal external diameters that are greater than 34.2 mm.5.4 Polytetrafluoroethylene (PTFE) Plugs, for closing thetest cells and made from pure PTFE.5.5 Insertion RodA metal rod with a threaded end usedfor inserting and removing the PTFE plugs from t

25、he test cells(see Fig. 1).5.6 Analytical BalanceAtop pan-type balance, capable ofweighing the test cells in an upright position to an accuracy ofat least 0.001 g.5.7 Beakers, 150 mL and 50 mL with pour spouts.5.8 Glass Stirring Rod, approximately 250-mm length.6. Reagents and Materials6.1 Purity of

26、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 are available.3Other grades may beused, provi

27、ded it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Reference Standardn-Dodecane.(WarningFlammable.)6.3 Relaxation Reagent Solution, prepared from ferricacetylacetonate (Fe(C5H7O2)3 MW = 353.16, reagentgr

28、ade)Prepare a fresh 0.02 M Fe(C5H7O2)3solution bydissolving 1.77 g of Fe(C5H7O2)3in 250 mL TCE. If any ofthe Fe(C5H7O2) remains undissolved, filter the solution, anduse the filtrate in subsequent steps.6.4 Tetrachloroethylene (TCE).(WarningCancer-suspectagent.)7. Sampling7.1 Take a homogeneous sampl

29、e in accordance with Prac-tice D4057. Mix the sample prior to taking a representativealiquot as the test specimen. Middle distillates, gas oils, and3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notli

30、sted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Conditioning Block and Insertion RodD4808 01 (2012)2residue ca

31、n require heating to facilitate mixing to obtain ahomogeneous test specimen, as described in 8.2.2.2 and 8.3.2.8. Preparation of Test Specimen and Standard8.1 Test Method ALight Distillates8.1.1 Take a clean and dry test cell and PTFE plug, andweigh them together to the nearest 0.001 g and record th

32、eweight. Add 30 6 1 mL of the reference standard or testspecimen to the tube, taking extreme care to prevent splashingthe liquid above the line inscribed on the tube. Use a pipet forthis operation.8.1.2 Using the insertion rod, push the PTFE plug into thetube until it is about 3 cm above the liquid

33、surface, beingcareful to keep the tube upright.Agentle twisting or rocking ofthe plug as it is inserted usually aids the escape of air from thetest cell and ensures that the lip of the PTFE plug is turned uparound the entire circumference. Take care to ensure that this isso, since a plug that is not

34、 properly inserted allows sampleevaporation and gives rise to erroneous results.NOTE 3If difficulties are encountered in the insertion of the PTFEplug, this operation is facilitated by inserting a length of thin (less than0.2-mm diameter) and clean copper wire down the inside surface of thetest cell

35、 until it is approximately 4 cm from the graduation mark, and thenpushing the PTFE plug down past the wire which is then removed.8.1.3 Unscrew the insertion rod carefully and remove with-out disturbing the plug and without contacting the liquid withthe under surface of the plug.8.1.4 Weigh the test

36、cell containing the test specimen orstandard and plug. Record this mass as MSor MR, respectively,to the nearest 0.001 g.8.1.5 Place the test cell in the sample conditioning block toequilibrate.8.1.6 Use procedures 8.1.1 through 8.1.5 to prepare both thereference and sample test cells.8.2 Test Method

37、 BMiddle Distillates, Gas Oils8.2.1 Reference Standard Preparation:8.2.1.1 Take a clean and dry test cell with PTFE plug and a150-mL beaker with glass rod. Weigh the test cell with plugand beaker with glass rod to the nearest 0.001 g and record astare masses.8.2.1.2 Add 20 g of the reference standar

38、d, n-dodecane, tothe beaker. Record this mass to the nearest 0.001 g as SM.8.2.1.3 To the beaker add 8.6 g TCE and 4.7 g of relaxationreagent solution, as described in 6.3, consisting of TCE andFe(C5H7O2)3(40 % dilution of reference standard with 1 mgrelaxation reagent/mL). Mix thoroughly using the

39、glass stirringrod.NOTE 4Burets can also be used to aid the addition of TCE andrelaxation reagent solutions.8.2.1.4 Transfer this solution from the beaker to the test cell,using the glass rod to prevent splashing the liquid above theline inscribed on the test cell. Fill the test cell to the prescribe

40、dlevel, just below this mark.8.2.1.5 Continue as in 8.1.2 and 8.1.3.8.2.1.6 Weigh the test cell containing the reference solutionand plug. Record the mass of the reference solution to thenearest 0.001 g as M1.8.2.1.7 Weigh the beaker and glass rod containing theunused solution, and record the mass o

41、f the remaining solutionto the nearest 0.001 g as M2.8.2.1.8 Place the test cell containing reference solution intothe conditioning block to equilibrate.8.2.2 Test Specimen Preparation:8.2.2.1 Take a clean and dry test cell with PTFE plug and a150-mL beaker with glass stirring rod. Weigh the test ce

42、ll withplug and the beaker with glass rod to the nearest mg, andrecord as tare masses.8.2.2.2 Add 20 g of the test specimen to the beaker. Recordthis mass to the nearest 0.001 g as SM. All samples shall behomogeneous prior to sampling. If the sample is viscous orcontains waxy materials, heat the sam

43、ple in its container toapproximately 60C and mix with a high-speed shear mixerprior to sampling.8.2.2.3 To the beaker containing sample, add 13.3 g of TCE(40 % dilution of the test sample with TCE). Mix the solutionthoroughly, using the glass rod.NOTE 5For some samples, it is necessary to heat and s

44、tir until thesample is completely homogeneous. Maintain the liquid level withadditional TCE during heating if necessary.8.2.2.4 Continue as in 8.2.1.4 through 8.2.1.8.8.3 Test Method CResidue8.3.1 Take a clean and dry test cell with PTFE plug, a150-mL beaker, and a glass rod. Weigh each of them to t

45、henearest 0.001 g, and record as tare weights.8.3.2 Add 15 g of reference standard or test specimen to thebeaker. Record this mass to the nearest 0.001 g as SM. Allsamples shall be homogeneous prior to sampling. If the sampleis viscous or contains waxy materials, heat the sample in itscontainer to a

46、pproximately 60C and mix with a high-speedshear mixer prior to sampling.8.3.3 To the beaker, add 17.2 g of TCE and 5.3 gofrelaxation reagent solution (60 % dilution with 1 mg ofrelaxation reagent per 1 mL). Mix thoroughly using the glassstirring rod (see 6.4).8.3.4 Continue, as described in 8.2.1.4

47、through 8.2.1.8.9. Preparation of Apparatus9.1 Read and follow the manufacturers instructions forpreparing the instrument to take measurements. Take specialcare to prevent the instrument and conditioning block fromexperiencing rapid temperature fluctuations; for example,avoid direct sunlight and dra

48、fts resulting from air conditioningor fans.9.2 Adequate temperature equilibration of the instrumentprobe assembly after adjustment to an elevated temperature isessential. Due to the size of test specimen and probe assemblyspecified by these methods, adequate thermal equilibrationmay require several

49、hours.9.3 The results obtained during the use of the instrument aresusceptible to error arising from changes in the local magneticenvironment. Exercise care to ensure that there is a minimumof metallic material in the immediate vicinity of the instrumentand keep this constant throughout the course of a series ofdeterminations.9.4 Set the instrument controls to the following conditions:D4808 01 (2012)3Parameter Test MethodATest MethodBTest MethodCGate width (G) 1.5 1.5 1.5Audio-Frequency Gain (Arb.units)500 400600 400600Radio-frequency Excitation (A