1、Designation: D7753 12Standard Test Method forHydrocarbon Types and Benzene in Light PetroleumDistillates by Gas Chromatography1This standard is issued under the fixed designation D7753; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 and provides for the quantita-tive determination of total saturates, total olef
3、ins, total aromat-ics and benzene in light petroleum distillates having a finalboiling point below 215C by multidimensional gas chroma-tography. Each hydrocarbon grouping as well as benzene canbe reported in both volume and mass percent.1.2 This test method is applicable to light petroleum distil-la
4、tes such as oxygenate-free motor gasoline or spark ignitionfuels, naphthas and hydrocarbon solvents over the contentranges from 1% (V/V) to 70 % (V/V) total olefins, 1 % (V/V)to 80 % (V/V) total aromatics and 0.2 to 10 % (V/V) benzene.This test method may apply to concentrations outside theseranges,
5、 but the precision has not been determined. Interlabo-ratory testing for precision used full range blending streams,such as FCC, reformates and spark ignition fuel or blendedmotor gasolines.1.3 This test method is not intended to determine oxygen-ated components. Light petroleum distillate products
6、such asmotor gasoline may contain oxygenates. Oxygenates such asmethyl tert-butyl ether (MTBE), tert-amyl methyl ether(TAME), ethyl tert-butyl ether (ETBE), ethanol and methanoletc. will coelute with specific hydrocarbon groups. If there isany suspicion the sample contains oxygenates, the absence of
7、oxygenates should be confirmed by other standard test methodssuch as Test Methods D4815, D5599,orD6839 before usingthis test method.1.4 This test method is not applicable for the determinationof individual hydrocarbon components with the exception ofbenzene. Test Method D6733 may be used to determin
8、e a largenumber of individual hydrocarbons to complement this testmethod.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its us
9、e. 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 prior to use.2. Referenced Documents2.1 ASTM Standards:2D4815 Test Method for Determination of MTBE, ETBE,TAME, DIPE, tertiary-Amyl
10、 Alcohol and C1to C4Alco-hols in Gasoline by Gas ChromatographyD5599 Test Method for Determination of Oxygenates inGasoline by Gas Chromatography and Oxygen SelectiveFlame Ionization DetectionD6733 Test Method for Determination of Individual Com-ponents in Spark Ignition Engine Fuels by 50-MetreCapi
11、llary High Resolution Gas ChromatographyD6839 Test Method for Hydrocarbon Types, OxygenatedCompounds and Benzene in Spark Ignition Engine Fuelsby Gas Chromatography3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 aromatics, nmass or volume % of monocyclicaromatics and polycycli
12、c aromatics (for example, naphtha-lenes), aromatic olefins and C8+cyclodienes compounds.3.1.2 C7+aromatics, nmass or volume % of all otheraromatics compounds (see 3.1.1) in sample not includingbenzene.3.1.3 olefins, nmass or volume % of alkenes, plus cy-cloalkenes and some di-olefins.3.1.4 olefins t
13、rap, nspecific column utilized to selectivelyretain olefins from mixture of olefins and saturates. The trapmust have good reversibility to capture and release olefins bychanging the temperature.3.2 Acronyms:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lu
14、bricants and is the direct responsibility of SubcommitteeD02.04.0L on Gas Chromatography Methods.Current edition approved Jan. 15, 2012. Published July 2012. DOI:10.1520/D7753-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org.
15、 For 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.3.2.1 BCEF- N,N-bis(a-cyanoethyl) formamidegas chro-matography stat
16、ionary phase.4. Summary of Test Method4.1 Fig. 1 shows a separation scheme of the various hydro-carbon types and benzene analysis. The instrumental configu-ration is shown in Fig. 2. The valves are actuated at predeter-mined times to direct different components to differentcolumns.As the analysis pr
17、oceeds, different hydrocarbon typesand benzene elute and are detected by a flame ionizationdetector (FID).4.2 The mass concentration of different hydrocarbon typesand benzene are determined by the application of averagerelative response factors to the areas of the detected peaksfollowed by normaliza
18、tion to 100%.4.3 The volume percent concentration of different hydrocar-bon types and benzene can be determined by the application ofaverage density factors to the calculated mass concentration ofthe detected peaks followed by normalization to 100%.4.4 This test method is not intended to determine c
19、om-pounds that contain oxygenates, such as ethanol, etc. Suchoxygenates interfere with the analysis of the hydrocarbons.4.5 Analysis time of a sample is approximately 15 min.5. Significance and Use5.1 Knowledge of the olefinic, aromatic, and benzene con-tent is very important in quality specificatio
20、ns of petroleumproducts, such as spark ignition fuels (gasoline) and hydrocar-bon solvents. Fast and accurate determination of hydrocarbontypes and benzene of petroleum distillates and products is alsoimportant in optimization of process units.5.2 This test method provides a fast standard procedure
21、fordetermination of hydrocarbon types and benzene in lightoxygenate-free petroleum distillates and products.6. Interferences6.1 C12+aliphatic hydrocarbon compounds (not includingC12) may not be fully separated from benzene in the polarcolumn, thus the determination of aromatics and benzene maybe aff
22、ected.6.2 Different types of oxygenated compounds in somepetroleum products will elute with specific hydrocarbon groupsand interfre with the analysis of the hydrocarbons.6.3 Commercial detergent, antioxidant, antiknock additivesand dyes utilized in some petroleum products have been foundnot to inter
23、fere with this test method.6.4 Dissolved water in samples has been found not tointerfere with this test method.7. Apparatus7.1 The analysis system is comprised of a gas chromato-graph with manual or automated sample injection, and specifichardware modifications. These modifications include columns,o
24、lefins trap, valves, and temperature controllers.7.2 Gas Chromatographcapable of temperature pro-grammed operation at specified temperature, equipped with avaporization inlet that can be a packed column inlet, a flameionization detector (FID), and necessary flow controllers.7.3 Sample Introduction S
25、ystemmanual or automatic in-jector, capable of injecting a 0.1 L volume of sample.Automated injector is recommended.7.4 Gas Flow or Pressure Controllerswith adequate pre-cision to provide reproducible flow rate of carrier gas to thechromatographic system, hydrogen and air for the flameionization det
26、ector. Control of air pressure for automatedvalves operation is required.7.5 Data Acquisition Systemchromatographic workstationshall meet the following specifications:7.5.1 Sampling rate of at least 10 points per second.7.5.2 Capacity for 100 peaks for each analysis.7.5.3 Normalized areas percent ca
27、lculation with responsefactors.7.5.4 Area summation of peaks that are split or of groups ofcomponents that elute at specific retention times.7.5.5 Noise and spike rejection capability.7.5.6 Manual baseline adjusting function, as required.7.6 Valvescolumn and trap switching, automated rotaryvalves ar
28、e recommended.7.7 Gas Purifiersto remove moisture and oxygen fromcarrier gas.7.8 Temperature Controllersthe independent temperaturecontrol of the polar column, olefins trap, switching valves andsample connecting lines is required. All of the system compo-nents that contact the sample should be heate
29、d to a temperaturethat will prevent condensation of any sample component. Table1 lists the system components and approximate operatingFIG. 1 Separation Scheme of Hydrocarbon Types and Benzene AnalysisD7753 122temperatures. Some of the components operate isothermally,while others require temperature
30、programming. Temperaturecontrol may be by any means that will meet the requirementslisted in Table 1.8. Reagents and Materials8.1 Gases:8.1.1 Carrier GasNitrogen or Helium. ILS precision ofthis test method was obtained using nitrogen as the carrier gas.Better than 99.999% pure. (WarningCompressed ga
31、sesunder high pressure.) Gas purifiers may be used to attain therequired purity or to ensure a stable signal baseline.8.1.2 HydrogenBetter than 99.999% pure. (WarningExtremely flammable gas under high pressure.) Gas purifiersmay be used to attain the required purity or to ensure a stablesignal basel
32、ine.NOTELegend:1injector2vaporization room3, 3Bvalve 14polar column5olefins trap6balance column7polar column oven 18olefins trap oven9valves oven10FID11data processing unitFIG. 2 Configuration of Analytical SystemTABLE 1 Temperature Control Ranges of System ComponentsComponent Typical OperatingTempe
33、rature, CHeatingModePolar Column 100120 isothermalOlefin Trap 125210 temperature programmed40C/minSwitching Valves 100140 isothermalSample Lines 100140 isothermalD7753 1238.1.3 Air, Compressed2.0. Theretention time ratio of benzene and toluene (ttoluene/tbenzene)shall be larger than 1.25, the resolu
34、tion shall be 1.1 (see Note1). A BCEF column which is 25% BCEF coated on acidwashing diatomite supporter is recommended as the polarcolumn. The length of the polar column is approximately 5 mand the inside diameter is approximately 2 mm. Other columnswhich meet the separation requirements can be use
35、d. Fig. 3 isa polar column separation performance check chromatogramwith system validation test sample.tbenzene/tundecene5 1.59Rbenzene/tundecene5 2.4ttoluene/tbenzene5 1.31Rtoluene/tbenzene5 1.25NOTE 1RS52tR2 tR1!Wb21 Wb15tR2 tR1Wb1where: tR2tR18.2.2 Olefin TrapThe olefin trap shall have excellentr
36、eversibility performance.At a lower temperature, for example,130C, the trap shall retain the olefins in the sample and passall saturates before benzene elutes from the polar column. At ahigher temperature, for example, 210C, the trap shall quanti-tatively release the retained olefins. The adsorbent
37、of olefinsusually is a silver ion based material. Any olefin trap whichsatisfies the performance requirements can be used. Theperformance of the trap can be verified first with the systemvalidation test sample (10.2) and, once established, can bemonitored either with the validation test sample or ac
38、tualproduction or consensus reference quality sample.8.3 System Gravimetric Validation Test SampleQuantitative mixtures of pure hydrocarbons are used to verifythe operating temperature, valve switching times and valida-tion of the system analysis accuracy. The validation samplecomposition and approx
39、imate component concentrations areshown in Table 2.8.4 Quality Control SamplesProduction or consensussamples, or both, used to routinely monitor validation ofanalysis system. Any production or interlaboratory or certifiedreference sample which approximates similar compositions tothe samples to be an
40、alyzed may be designated as the qualitycontrol sample. Quality control samples shall be selected suchthat they fall within the range and composition of samples to beanalyzed. The quality control samples shall be stable for aspecified period of use and storage conditions. It is preferredthat the qual
41、ity control samples be ampoulized to safeguardtheir composition integrity.9. Preparation of Apparatus9.1 The configuration of the analyzer system is shown inFig. 1. Some system modules may have independent tempera-ture controlled components. If using a commercial analyzer,consult the manufacturers i
42、nstructions or guidelines for prepa-ration of the instrument.FIG. 3 Polar Column Separation Performance Check ChromatogramD7753 1249.2 All supply gas pressure shall be adequate to ensureproper mass flow control and air or nitrogen actuated valveoperation. The approximate supplying gas pressure value
43、s arelisted in Table 3.9.3 Impurities in the carrier gas will have a detrimentaleffect on the performance of column and olefin trap. Therefore,appropriate gas purifiers shall be installed to ensure goodquality gases.9.4 The system validation test sample or quality controlsample can be used to determ
44、ine the valve switching times. Theolefins trap temperature is determined in order to meet theretention requirement for olefins. The approximate instrumentoperating conditions are listed in Table 4.10. System Checks and Standardization10.1 Instrument System Reliability CheckingThe check-ing of the an
45、alytical system is very important to ensure testresults reliability. The following gives a guideline:10.1.1 Use the system gravimetric validation test sample in8.3 to establish the quantitative performance of the system. Thestandard is used during setting up the instrument and periodi-cally afterwar
46、ds to verify its performance. The required abso-lute deviation between obtained results and blending concen-tration values as specified in Table 2 is 1.6% for total saturates,1.2% for total olefins, 1.4% for total aromatics, and 0.05% forbenzene.10.1.2 Quality Control (QC) SamplePreferably fromsimil
47、ar production, or from an interlaboratory study or equiva-lent, or a combination thereof. Such quality control samples isused to routinely monitor the operation of the chromatographicsystem and verify that reported concentrations are within theprecision of the test method. The quality sample shall b
48、eanalyzed for each batch of samples. Depending on the rangeand composition of the samples to be analyzed, more than onequality control sample may be necessary. The QC sample shallbe of sufficient volume to provide an ample supply for theintended period of use and it shall be homogeneous and stableun
49、der the anticipated storage conditions. The quality controlsample should have similar composition and hydrocarbondistribution as the sample with highest olefin concentrationroutinely analyzed to safeguard against potential olefin break-through from the olefin trap. The sample is analyzed usingprocedure described in 11.3 and monitored by SQC.10.2 Olefin Trap Performance CheckingThe olefin trap isone of the most critical parts in the test system. If the olefin trapis ineffective or cannot meet the performance requirements, thetest
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1