ASTM D7347-2015 red 6427 Standard Test Method for Determination of Olefin Content in Denatured Ethanol by Supercritical Fluid Chromatography《采用超临界流体色谱法测定变性汽油中链烯含量的标准试验方法》.pdf
《ASTM D7347-2015 red 6427 Standard Test Method for Determination of Olefin Content in Denatured Ethanol by Supercritical Fluid Chromatography《采用超临界流体色谱法测定变性汽油中链烯含量的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM D7347-2015 red 6427 Standard Test Method for Determination of Olefin Content in Denatured Ethanol by Supercritical Fluid Chromatography《采用超临界流体色谱法测定变性汽油中链烯含量的标准试验方法》.pdf(12页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: D7347 071D7347 15Standard Test Method forDetermination of Olefin Content in Denatured Ethanol bySupercritical Fluid Chromatography1This standard is issued under the fixed designation D7347; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e 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 NOTEAdded research report footnote to Section 13 editorially in October 2008.1. Scope Scope*1.1
3、This test method covers the determination of the total amount of olefins in denatured ethanol to be used as an oxygenateadditive in blended spark ignition engine fuels. The method of determination is supercritical fluid chromatography (SFC). Theapplication range is from 0.1 mass percent to 1.0 mass
4、percent total olefins. Results are expressed in terms of mass percent olefins.1.2 This test method can be used for the analysis of denatured ethanol that is intended to be used as an oxygenate additive incommercial spark ignition engine fuels.1.3 The values stated in SI units are to be regarded as t
5、he standard. The values given in parentheses are for information only.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
6、 applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density MeterD5186 Test Method for Determination of theAromatic Content and PolynuclearAromatic Content of Diesel Fue
7、ls andAviationTurbine Fuels By Supercritical Fluid ChromatographyD6550 Test Method for Determination of Olefin Content of Gasolines by Supercritical-Fluid Chromatography3. Terminology3.1 Definitions:3.1.1 critical pressure, nthat pressure needed to condense a gas at the critical temperature.3.1.2 cr
8、itical temperature, nhighest temperature at which a gaseous fluid can be converted to a liquid by means ofcompression.3.1.3 supercritical fluid, nfluid maintained in a thermodynamic state above its critical temperature and critical pressure.3.1.4 supercritical fluid chromatography, n class of chroma
9、tography that employs supercritical fluids as mobile phases.4. Summary of Test Method4.1 Asmall aliquot of the denatured alcohol sample is injected onto a set of three analytical chromatographic columns connectedin series. The sample is transported through the columns using supercritical carbon diox
10、ide (CO2) as the mobile phase. The firstcolumn is packed with polyvinyl alcohol (PVA). The second column in the series is an analytical column packed with high surfacearea silica gel particles, and the third column is packed with silica particles coated with strong cation exchange material loadedwit
11、h silver ions.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.04.0C on Liquid Chromatography.Current edition approved Aug. 1, 2007Dec. 1, 2015. Published September 2007February 2
12、016. Originally approved in 2007. Last previous edition approved in 2007 asD7347 071. DOI: 10.1520/D7347-07E01.10.1520/D7347-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information
13、, refer to the standards Document Summary page on the ASTM website.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. Becauseit may not be technically possible to adequately depict a
14、ll 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 appears at the end of this standardCopyright ASTM International,
15、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Two six-port switching valves are used to direct the different classes of components through the chromatographic systemto the detector. In a forward flow mode, saturates, aromatics, and olefins pass onto the anal
16、ytical silica gel column while the alcoholis retained on the PVA column. The saturates, aromatics, and olefins are maintained on the silica column, while the alcohol isback-flushed to the detector. This step frees the flow path of alcohol species allowing for the separation of the olefins from satur
17、atesand aromatics. The forward flow mode is resumed after the alcohol is eliminated and saturates are carried to the detector, whilethe aromatics are retained on the silica column and the olefinic species are trapped on the silver-loaded column. The next step isto back-flush the olefins from the sil
18、ver-loaded column to the detector. Finally the aromatics are carried from the silica column tothe detector in a forward flow mode, bypassing the silver-loaded column.4.3 A flame ionization detector (FID) is used for quantitation. Calibration is based on the area of the chromatographic signalfor olef
19、ins, relative to standard reference materials, which contain a known mass percent of total olefins as corrected for density.5. Significance and Use5.1 Olefinic hydrocarbons that may be present in denatured ethanol have been demonstrated to contribute to photochemicalreactions in the atmosphere, and
20、this can result in the formation of smog in susceptible urban areas.5.2 The California Air Resources Board (CARB) has specified a maximum allowable limit of total olefins in spark ignitionengine fuel. Denatured ethanol will be added at the terminals as an oxygenate additive and can contain olefinic
21、species contributingto the total olefins present in spark ignition engine fuel. An analytical method is therefore necessary to determine total olefins indenatured ethanol intended for spark ignition engine fuel use. The test method is intended to be used by both regulators andproducers.5.3 The prese
22、nt test method is automated, does not require any sample preparation, and has a relatively short analysis time ofapproximately 20 min.6. Apparatus6.1 Supercritical Fluid Chromatograph (SFC)Any SFC instrumentation can be used that has the following characteristics andmeets the performance requirement
23、s specified in Section 8.NOTE 1SFC instruments suitable for Test Method D6550 are suitable for this test method if equipped with a second column heater as described in6.1.5.1 and columns as described in 6.1.4.6.1.1 PumpThe SFC pump shall be able to operate at the required pressures (typically up to
24、about 30 MPa) 30 MPa) anddeliver a sufficiently stable flow to meet the requirements of retention time precision (better than 0.3%)0.3 %) and detectionbackground (Section 8). The characteristics of the pump largely determine the optimum column diameters. Columns with an insidediameter of 1.0-mm1.0 m
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