1、Designation: D7920 151Standard Test Method forDetermination of Fuel Methanol (M99) and Methanol FuelBlends (M10 to M99) by Gas Chromatography1This standard is issued under the fixed designation D7920; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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.1NOTESection 16 was corrected editorially in September 2015.1. Scope1.1 This test method covers the
3、determination of the metha-nol content, by gas chromatography, of M10 to M99 inmethanol fuel blends, including fuel methanol (M99).1.1.1 Methanol may be determined from 10 % to 99 % byvolume.1.2 This test method is designed to measure not onlymethanol in the blended gasoline but also the impurities
4、in fuelmethanol (M99) itself in the range of 5 mg/kg to 1000 mg/kg.However, not all impurities are measured nor detected by thistest method.1.2.1 Water cannot be determined by this test method andshall be measured by a procedure such as Test Method D1364and the result used to correct the concentrati
5、ons determined bythis test method.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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
6、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:2D1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)D4057 Practice for Manual S
7、ampling of Petroleum andPetroleum ProductsD4175 Terminology Relating to Petroleum, PetroleumProducts, and LubricantsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4814 Specification for Automotive Spark-Ignition EngineFuelD4626 Practice for Calculation of Gas Chromato
8、graphicResponse FactorsD5797 Specification for Fuel Methanol (M70-M85) for Au-tomotive Spark-Ignition EnginesD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceE29 Practice for Using Significant Digits in Test
9、Data toDetermine Conformance with SpecificationsE355 Practice for Gas Chromatography Terms and Relation-shipsE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid ChromatographyE1064 Test Method for Water in Organic Liquids by Coulo-metric Karl Fischer TitrationE1510
10、 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs3. Terminology3.1 This test method makes reference to many commonchromatographic procedures, terms, and relationships. Detaileddefinitions can be found in Terminology D4175 and PracticesD4626, E355, and E594.3.2
11、 Definitions:3.2.1 analyte, na specific compound to be measuredquantitatively in a mixture of compounds.3.2.2 analytical column, na chromatographic column usedto further separate a specific analyte from a mixture ofcompounds which can coelute in the primary column.3.2.3 analytical detector, na devic
12、e used to quantify thecompounds of interest after they elute from the analyticalcolumn.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current
13、edition approved Aug. 1, 2015. Published September 2015. DOI:10.1520/D7920-15E01.2For 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
14、 onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 fuel methanol (M99), nmethyl alcohol produced forthe purpose of blending with gasoline to make a fuel forspark-ignition internal combustion engines.3.2.4.1 Disc
15、ussionFuel methanol is typically producedwith 99 % by volume methyl alcohol.3.2.5 gasoline, na volatile mixture of liquidhydrocarbons, generally containing small amounts ofadditives, suitable for use as a fuel in spark-ignition internalcombustion engines. D48143.2.6 heart-cut, nin gas chromatography
16、, a procedure inwhich the analyte in question is transferred from one column toa different column, usually of the opposite polarity.3.2.7 internal standard (IS), na high purity compound notpresent in the sample which is added to the sample and used tocalculate quantitatively the component of interes
17、t.3.2.7.1 DiscussionThe internal standard is added in aconstant amount to all calibration standards, see 7.4.2.1.3.2.8 mass response factor (MRF), na constant of propor-tionality that converts area percent to mass percent.3.2.9 methanol, nmethyl alcohol, the chemical compoundCH3OH.3.2.10 methanol fu
18、el blend, na fuel consisting primarily ofa mixture of methanol with gasoline.3.2.10.1 DiscussionTypically methanol fuel blends are70 % to 85 % by volume, identified as M70 to M85.3.2.11 microfluidic device, na chromatographic switchingvalve constructed with micro channels, usually having fiveports a
19、nd to which the columns, restrictors and auxiliarypressure devices are connected in order to carry out a heart-cut.3.2.11.1 DiscussionAn auxiliary carrier gas is fed to thedevice which has two ports of entry such that switching thecarrier gas from one port to the other results in changing thedirecti
20、on of the flow of the primary column to either a restrictoror to the analytical column.3.2.12 monitor detector, na device used to measure theelution of the analyte from the primary column.3.2.12.1 DiscussionThe monitor detector is used to deter-mine the heart-cut time (see 6.1.1), that is, the time
21、where thepeak of interest begins and where the peak of interest ends.3.2.13 MXX, nan abbreviation that represents a fuel con-sisting primarily of methanol (methyl alcohol) and hydrocar-bons in which XXis the percent by volume of methanol in theblended fuel.3.2.14 primary column, nin chromatography,
22、a deviceused to perform a primary separation of a mixture of com-pounds.3.2.14.1 DiscussionThe primary column, also known as amonitor column, is used to separate the analyte of interest andto determine the start time and the end time of the heart-cut.4. Summary of Test Method4.1 The sample is inject
23、ed in to the gas chromatographwhere components are separated in the primary column andsubsequently are eluted through the restrictor and detected bythe monitor detector. The methanol is identified and theheart-cut window is determined. The instrument settings are setto transfer the methanol from the
24、 primary column to theanalytical column. A further separation takes place in theanalytical polar column suitable for the polarity of methanol.After elution from the secondary column, the methanol isanalyzed by the analytical detector. Fuel methanol (M99) isanalyzed by the primary column only without
25、 the execution ofa heart-cut. Analysis is made in the monitor detector. In thecase of fuel methanol (M99) the mass percent is determined bydifference.5. Significance and Use5.1 Methanol is used in blends with gasoline at levels of70 % to 85 % by volume, as specified in Specification D5797.This test
26、method provides a quantitative approach to measurethe methanol content in methanol fuel blends, from 10 % to99 % by volume. The usual concentration is 70 % to 85 % byvolume (M70 to M85). The method is also used to analyze fuelmethanol (M99) prior to blending.6. Apparatus6.1 Gas Chromatograph, capabl
27、e of operating at the condi-tions listed in Table 1 and Table 2. A heated flash vaporizinginlet, also known as a split inlet, is designed to provide a linearsample split injection (for example, 500:1). This inlet isrequired for proper sample introduction. Carrier gas controlsshall be of adequate pre
28、cision to provide reproducible columnflows and split ratios in order to maintain analytical integrity.Pressure and flow control devices used shall be designed toattain the linear velocity required for optimum operation of thecolumns. Two separate flame ionization detectors are requiredfor this test
29、method. The use of one detector alone is notpossible as the setting of the heart-cut times will be difficultand the reliability of the exact cut time determination may becompromised. Detectors should meet the sensitivity criteria ofPractice E594.6.1.1 A heart-cut is a technique which utilizes a swit
30、chingdevice to which the following five (5) components are con-nected: (1) a primary column, usually non-polar which spansfrom the inlet to the device, (2) an analytical column, usuallyTABLE 1 Conditions for Analysis of Methanol Fuel BlendCarrier HeliumValve ON interval, min 2.372.60 3.253.36Inlet t
31、emperature, C 250Split ratio 500/1Primary column pressure, kPa 259.2Primary column flow, mL/min 2Analytical column pressure, kPa 190.1Analytical column, flow, mL/min 3Oven, initial T C 50Initial hold time, min 5.5Oven temperature rate, C /min 15Final oven temperature, C 190Final hold time, min 3Anal
32、ytical FID, T C 300Hydrogen, mL/min 45Air, mL/min 450Make up, N2mL/min 25Monitor, FID, T C 300Hydrogen, mL/min 45Air, mL/min 450Make up, N2mL/min 25Volume injected, L 0.2D7920 1512a polar column, that spans from the device to the analyticaldetector, (3) a restrictor or a tubing of small diameter whi
33、chconnects from the device to a second detector whose functionis to serve as the monitor detector, (4) an external pressuredevice which controls the pressure at the point where the twocolumns coincide, and finally, (5), a solenoid that directs thepressure to the two points of the device. By switchin
34、g theapplied pressure, the components eluting from the primarycolumn can either be sent to the monitor detector or to theanalytical column where further separation occurs and thus thecompounds of interest elute at the analytical detector.6.2 Sample Introduction SystemAutomated liquid injec-tion to t
35、he split inlet is required. Devices capable of 0.2 L to2.0 L injections is suitable.6.3 ColumnsThe precision for this test method was devel-oped utilizing fused silica open tubular columns with non-polarpolydimethylsiloxane bonded (cross-linked) phase coating anda polyethylene glycol coated fused si
36、lica column.6.3.1 Primary ColumnAn open tubular column with anon-polar polydimethylsiloxane bonded (cross-linked) phasecoating, having 30 m by 0.25 mm with a 0.25 m filmthickness, is used as primary column. This column is installedfrom the split inlet to the microfluidic device. Follow PracticeE1510
37、 for column installation at the split inlet. The column isalso inserted to the proper port of the microfluidic device withan appropriate ferrule. Follow the instructions of the manufac-turer of the microfluidic device when inserting the column andsetting the ferrule to the column. Utmost care is req
38、uired whenmaking the connection of the ferrule to the device in order notto crack the fused silica column.6.3.2 Analytical ColumnA second open tubular column,30 m by 0.25 mm with a film thickness 0.25 m, containing apolyethylene glycol phase which is a polar phase. One end ofthis analytical column i
39、s inserted into the microfluidic deviceand the opposite end is connected to the analytical detector.Observe the same precautions in making the connections asdescribed in 6.3.1.6.3.3 A balance restrictor is required; composed of inertdeactivated fused silica whose dimensions provide the sameflow resi
40、stance as that of the analytical column while minimiz-ing the holdup time of peaks eluting from the primary columnto the monitor detector. A typical sized restrictor will be ofapproximately1minlength and 0.1 mm internal diameter. Itis connected from the device to the monitor detector. Thislength is
41、sufficient to accommodate the equivalent pneumaticresistance of the analytical column. The dimensions of therestrictor facilitate the fast transfer of the eluents from theprimary column so as to provide negligible delay in reachingthe monitor detector. Thus accurate cut times can be deter-mined.6.4
42、Microfluidic DeviceThe microfluidic device shall betreated to become inert in order to avoid adsorption of anycomponents in the sample. It shall be manufactured withextremely small volumes and grooves so as not to introducepeak broadening or dead volumes. These devices are availablefrom several manu
43、facturers.6.5 Electronic Pressure ControlAn electronic means ofcontrolling the auxiliary pressure is required to cause thetransfer of the components from the primary column to theanalytical column. This controller is connected to the micro-fluidic device through a solenoid. The pressure controller m
44、ustbe capable of controlling pressures to within at least 0.069 kPa.6.6 SolenoidDevice required to switch the direction of theflow from the restrictor point to the analytical column point.Typical solenoids should be capable of executing more thanone million cycles. The solenoid should be free of com
45、ponentsthat may interfere with the analysis. When the solenoid is in theoff position the flow of the primary column is sent to themonitor detector (Fig. 1(a). When the solenoid is in the onposition, the flow of the primary column is sent to theanalytical column and subsequently to the analytical det
46、ector(Fig. 1(b). A shunt restrictor is placed across the output of thesolenoid which provides a trickle of flow to the unsweptsection.6.7 The gas chromatograph requires a means to program thepressures required for the transfer of components from theprimary to the analytical column as well as to cont
47、rol the inletpressure during the analysis so as to perform backflush. It isessential that the gas chromatograph be provided with accurateand reproducible oven temperature control. Control may bethrough hardware or software of the gas chromatograph. Inaddition software is required to integrate the si
48、gnals andperform internal standard and or external standard calculationsas required.6.8 A data system is required to acquire data and to controlthe gas chromatographs operational variables.Adata system isrequired to perform calibrations and analysis in the internalstandard mode. The data systems req
49、uire that sample mass andinternal standard mass be entered. The calculation of responsefactors are described in Practice D4626.7. Reagents and Materials7.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallTABLE 2 Conditions for Analysis of Methanol Fuel BlendCarrier HydrogenValve ON interval, min 1.42-1.52 1.942.06Inlet temperature, C 250Split ratio 500/1Primary column pressure, kPa 172.6Primary column flow, mL/min 2.5Analytical column pressure, kPa 120.7Analytical
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