ASTM D7900-2018 Standard Test Method for Determination of Light Hydrocarbons in Stabilized Crude Oils by Gas Chromatography.pdf

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1、Designation: D7900 17D7900 18Designation: 601Standard Test Method forDetermination of Light Hydrocarbons in Stabilized CrudeOils by Gas Chromatography1,2This standard is issued under the fixed designation D7900; the number immediately following the designation indicates the year oforiginal adoption

2、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. Scope*1.1 This test method specifies a method to determine the boiling range distribut

3、ion of hydrocarbons in stabilized crude oil upto and including n-nonane. A stabilized crude oil is defined as having a Reid Vapor Pressure equivalent to or less than 82.7 kPa.The results of this test method can be combined with those from Test Method D7169 and IP 545 to give a full boiling pointdist

4、ribution of a crude oil. See Test Method D7169 (IP 545) for merging of these results to give a full crude analysis.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for informationpurposes only.1.3 This standard does not purport to add

5、ress all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use.1.4 This international standard was develo

6、ped in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Document

7、s2.1 ASTM Standards:3D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD5134 Test Method for Detailed Analysis of Petroleum Naphthas thr

8、ough n-Nonane by Capillary Gas ChromatographyD6729 Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100 Metre Capillary HighResolution Gas ChromatographyD6730 Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100Metre Cap

9、illary (withPrecolumn) High-Resolution Gas ChromatographyD6733 Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 50-Metre Capillary HighResolution Gas ChromatographyD7169 Test Method for Boiling Point Distribution of Samples with Residues Such as Crude Oils and

10、 Atmospheric and VacuumResidues by High Temperature Gas ChromatographyE355 Practice for Gas Chromatography Terms and Relationships2.2 Energy Institute Standards:4IP 545 Crude Petroleum and Petroleum ProductsDetermination of Boiling Range Distribution of Crude OilIP 475 Manual Sampling1 This test met

11、hod is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.04.0L on Gas Chromatography Methods.Current edition approved Oct. 1, 2017Oct. 1, 2018. Published October 2017October 2018. Originally approved in

12、 2013. Last previous edition approved in 20132017 asD7900 13D7900 17.1. DOI: 10.1520/D7900-17.10.1520/D7900-18.2 This standard has been developed through the cooperative effort between ASTM and the Energy Institute, London. The IP and ASTM logos imply that the ASTM andIP standards are technically eq

13、uivalent, but their use does not imply that both standards are editorially identical.3 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 standards Document Summary p

14、age on the ASTM website.4 Information on Energy Institute Standards can be obtained from the Energy Institute at www.energyinst.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 version.

15、 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 section

16、appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1IP 476 Automatic Pipeline Sampling2.3 ISO Standard:5ISO 4259 Petroleum ProductsDetermination and Application of Precision Data in Relation to Methods o

17、f Test3. Terminology3.1 DefinitionsThis test method makes reference to many common gas chromatographic procedures, terms, and relationships.Detailed definitions can be found in Practice E355.4. Summary of Test Method4.1 An amount of internal standard is quantitatively added to an aliquot of the stab

18、ilized crude oil. A portion of this mixtureis injected into a pre-column in series via a splitter with a capillary analytical column.When the n-nonane has quantitatively passedto the analytical column, the pre-column is back-flushed to vent the higher boiling components. The individual components ar

19、eidentified by comparison with reference chromatograms and a database of hydrocarbon compounds (see Appendix X1). Theboiling point distribution up to and including n-nonane (n-C9) is calculated.5. Significance and Use5.1 Knowledge of the boiling point distribution of stabilized crude oils is importa

20、nt for the marketing, scheduling, andprocessing of crude oil in the petroleum industry. Test Method D7169 and IP 545 purport to give such a distribution in crude oils,but are susceptible to significant errors in the light ends portion of the distribution as well as in the mass recovery of the wholec

21、rude oil due to the interference imposed by the diluent solvent. This test method allows for more accurate determination of thefront end of the boiling point distribution curve, in addition to providing important C1 to C9 (nonane) component levelinformation, and more accurate mass recovery at C9 (no

22、nane).6. Apparatus6.1 Gas Chromatograph, with the operational characteristics given in Table 1.6.2 InletA temperature programmable vaporizing (PVT) or split/splitless inlet.6.2.1 Carrier Gas Pneumatic ControlConstant carrier gas pressure or flow control is required.6.3 ColumnA fused silica-bonded po

23、lydimethylsiloxane coated capillary column and pre-column are employed. See Table 1for suggested columns. The analytical column shall elute hydrocarbons in a boiling point order. The eluate from the injector passesthrough the pre-column before eluting onto the analytical column.6.4 Data SystemAcompu

24、ter-based chromatography data system capable of accurately and repeatedly measuring the retentiontime and areas of eluting peaks. The system shall be able to acquire data at a rate adequate to accurately measure 10 to 20 pointsaround an individual peak. For the accelerated methods (see Table 1), a s

25、ampling rate of at least 20 Hz is recommended.6.5 Sample IntroductionSample introduction by means of an automatic injection is highly recommended.5 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.TABLE 1 Typical Chromatog

26、raphic ConditionsPre-column Pre-column Analytical AcceleratedA B AnalyticalColumn Lengthmetres 1.0 m 0.075 m 50 or 100 m 40 mColumn Internal Diametermm 2 mm 2.5 mm 0.25 mm 0.10 mmPhase Loading 5 % 10 %Film Thickness 0.5 umInjection Volume 0.1 L 0.1 LInjector Split Ratio 100 : 1 600 : 1Injector Tempe

27、rature 300 C 100 CPre-column Temperature 200 C 100 CInjector Prog. Rate C/min 50 C minFinal Injector Temperature 300 CInitial Oven Temperature 35 C 35 CHold Time 30 min 2.6 minOven Program Rate C/min 2 C min 50 C min 45 C(hold time 3 min)5 C min 60 C(hold time 3 min)9.5 C min Final Oven Temperature

28、200 C (hold time 20 min) 200 C (hold time 1 min)Flame Ionization Detector 300 C 300 CD7900 1826.6 Flame Ionization Detector (FID), with sufficient sensitivity to detect 0.01 % mass n-heptane with a signal to noise of greaterthan five. When operating at this sensitivity level, detector stability shal

29、l be such that a baseline drift of not more than 1 % perhour is obtained. The detector shall be connected to the column so as to avoid any cold spots. The detector shall be capable ofoperating at a temperature equivalent to the maximum column temperature used.6.7 Pre-Column Configurations:6.7.1 Heat

30、ed Valve Switching Box ConfigurationFor the isothermal 1 m pre-column, a heated valve box is needed with its owntemperature control. The box will contain an automated six-port valve, which is used to back-flush the pre-column. The six-portvalve should be made out of material that will not be corrode

31、d by the sample (some crude oils contain high amounts of sulfurcomponents). The valve shall be situated in a heated isothermal oven and be attached to the injector, pre-column, splitter, analyticalcolumn, and the detector without any cold spots. An example configuration is given in Fig. X2.1 in Appe

32、ndix X2. Alternatively,a Dean Switch type back-flush of the petroleum may also be employed in place of a rotary valve.6.7.2 Injection Port Back-Flush ConfigurationA temperature programmable injection port capable of containing a 7.5 cmpre-column, and this injection port must be equipped with a back-

33、flush option. This injector can be connected directly to thecapillary column (Fig. X2.2, Appendix X2) or via a splitter (Fig. X2.3, Appendix X2).6.8 Analytical Balance, capable of weighing with an accuracy of 0.1 mg.7. Reagents and Materials7.1 Gas Chromatograph GasesAll of the following gases shall

34、 have a purity of 99.995 % (VV) or greater. (WarningGasesare compressed. Some are flammable, and all gases are under high pressure.)NOTE 1These specifications can be obtained by proper use of filtering devices and meeting the FID specifications in 6.6.7.1.1 Carrier GasHelium or hydrogen is required.

35、Any oxygen present shall be removed, for example, by a suitable chemicalfilter. If hydrogen is employed as a carrier gas, the user is advised to follow all manufacturers safety guidelines for its use.(WarningHydrogen is an extremely flammable gas under high pressure.)7.1.2 Detector Combustion Gases,

36、 Air, Hydrogen, and Make-up Gas (Helium or Nitrogen). (WarningHydrogen is anextremely flammable gas under high pressure.) (WarningCompressed air is a gas under high pressure and supports combustion.)7.2 Internal StandardThe internal standard shall have baseline resolution from any adjacent eluting p

37、eaks. Hexene-1 or3,3dimethylbutene-1 (99 % pure) have been found to be suitable.7.3 Valve Timing Mixture/Splitter Linearity MixAquantitative mixture of approximately 1 % mass of each normal alkane frompentane to decane in hexadecane (99+ % purity). Accurately record the mass (g) of each normal alkan

38、e as well as the hexadecanesolvent and calculate the actual mass percent of each alkane in the mixture.7.4 Viscosity Agent, Carbon disulfide, 99+ % pure, (WarningExtremely flammable and toxic liquid) is used as a viscosityreduction agent in the preparation of samples.8. Sampling8.1 Samples to be ana

39、lyzed by this test method must be obtained using the procedures outlined in Practice D4057 or PracticeD4177 (IP 475 and IP 476, respectively).8.2 The test specimen to be analyzed must be homogeneous and free of dust or undissolved material.9. Preparation of Apparatus9.1 ChromatographPlace in service

40、 according to manufacturers instructions. Typical operating conditions are given in Table1.9.2 Column PreparationCondition analytical columns in accordance with manufacturers instructions.9.3 System Performance Specification:9.3.1 SkewnessDetermine the skew of the n-hexane peak by measuring the widt

41、h of the leading part of the peak at 5 % peakheight (A) and the width of the following part of the peak at 5 % peak height (B). The ratio (B)/(A) shall be not less than 1 ormore than 4 (see Fig. 1).9.3.2 Column ResolutionDetermine the resolution between the internal standard and the nearest n-paraff

42、in peak.R523t2 2 t1!1.699w11w2! (1)where:R = the column resolution,t1 = the retention time of the first peak (peak 1),t2 = the retention time of the second peak (peak 2),w1 = the peak width at half height of peak 1, andw2 = the peak width at half height of peak 2.D7900 183For example, if Hexene-1 is

43、 used as the internal standard, the resolution is determined between Hexene-1 and n-hexane. Theresolution shall be at least 2.0.9.3.3 Detector Response Factor CalculationsCalculate the flame ionization detector response factor relative to methane,which is considered to have a response factor of unit

44、y (1), for each hydrocarbon group type of a particular carbon number usingEq 2.RRf 5Caw 3 Cn!1Haw 3 Hn!# 30.7487Caw 3 Cn!(2)where:RRf = relative response factor for a hydrocarbon type group of a particular carbon number,Caw = atomic mass of carbon, 12.011,Cn = number of carbon atoms in the hydrocarb

45、on type group, of a particular carbon number,Haw = atomic mass of hydrogen, 1.008,Hn = number of hydrogen atoms in the hydrocarbon type group of a particular carbon number, and0.7487 = factor to normalize the result to a methane response of unity, (1).9.3.4 Determination of Back-Flush TimeWith the p

46、re-column and analytical column in series, inject an aliquot of thepre-column switch test mixture (7.3) and determine the ratio of the alkanes.9.3.4.1 Non-Accelerated Analytical ColumnSet the switching time to one minute and repeat the analysis. Increase or decreasethe valve time to ensure the compl

47、ete recovery of the highest alkane required (for example, n-nonane) and partial recovery of thenext alkane (for example, decane). (See example chromatogram (Fig. 3).)9.3.4.2 Accelerated Analytical ColumnSet the switching time to 30 s and repeat the analysis. Increase or decrease the valvetime to ens

48、ure the recovery of the highest alkane required (for example, n-nonane) and partial recovery of the next alkane (forexample, n-decane). (See example chromatogram (Fig. 3).)9.3.5 Split Injection LinearityFor systems utilizing split injection, injector linearity must be established to determine proper

49、quantitative parameters and limits.9.3.5.1 Set the injector temperature and split ratio to the operating values as indicated in Table 1 for split inlets.9.3.5.2 Inject 0.1 L of the splitter linearity mixture (7.3) into the system.9.3.5.3 Calculate the normalized area % of the n-C5 through n-C9 paraffins using Eq 3:Corrected Normalized Area %Cn1003Area Cn 3 RRf Cn!TA# (3)where:Area Cn = integrated peak area of normal alkane Cn,RRf Cn = theoretical relative response factor for Cn (Eq 2), andTA = su