1、Designation: E 1746 08Standard Test Method forSampling and Analysis of Liquid Chlorine for GaseousImpurities1This standard is issued under the fixed designation E 1746; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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 covers sampling and analysis of liquidchlorine for the determination of oxygen (200 to 400 g/g),nitrog
3、en (400 to 800 g/g), and carbon dioxide (800 to 1000ppm) content at levels normally seen in liquid chlorine.Hydrogen and carbon monoxide concentrations in liquid chlo-rine are typically at or below the detection limit of this testmethod.NOTE 1The minimum detection limit of hydrogen usinga1cm3gassamp
4、le and argon carrier gas is 100 to 200 g/g.2The detection limit forthe other components is significantly lower.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 Review the current Material Safety Data Sheets (MSDS)for deta
5、iled information concerning toxicity, first aid proce-dures, and safety precautions.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
6、 determine the applica-bility of regulatory limitations prior to use. Specific hazardsstatements are given in Section 7.2. Referenced Documents2.1 Code of Federal Regulations:349 CFR 173, Code of Federal Regulations Title 49, Trans-portation: Shippers General Requirements for Shipmentsand Packaging,
7、 including the following sections:173.304 Charging of Cylinders with Liquefied CompressedGas173.314 Requirements for Compressed Gases in Tank Cars173.315 Compressed Gases in Cargo Tanks and PortableTank Containers2.2 Other Document:Chlorine Institute Pamphlet No. 77 Sampling Liquid Chlo-rine43. Summ
8、ary of Test Method3.1 Asample of liquid chlorine is trapped in a sampling tubeand vaporized into a steel bomb. The vaporized chlorine in thesteel bomb is introduced into a gas chromatograph by a gassampling loop (1 cm3) using a ten-port gas sampling andswitching valve. The separations are made on a
9、Porapakt Qcolumn and on a 5Amolecular sieve column whose lengths aresuch that the peaks do not overlap.3.2 Any component that co-elutes with the components ofinterest may interfere with this analysis.4. Significance and Use4.1 It is very difficult to exclude sample contamination byambient air during
10、 the process of sampling. The levels ofatmospheric contamination caused by poor sampling methodsare often equal to or larger than the levels of the gaseousimpurities present in the chlorine. This results in markedlyelevated levels of detected impurities. As specifications be-come tighter, it becomes
11、 more important to measure thegaseous impurity levels in liquid chlorine correctly.4.2 Additional problems are experienced in the sampling ofliquefied gases for the gaseous impurities. The gaseous impu-rities reach an equilibrium between the liquid phase and vaporphase in a sample bomb. The quantity
12、 of gases measured in anyparticular sample containing both liquid and vapor will be afunction of the amount of vapor space in the sample bomb.This test method avoids the presence of liquid in the samplebomb.5. Apparatus5.1 Gas ChromatographShimadzu GC-8AIT equipped asshown in Fig. 1, or equivalent,
13、equipped with a thermalconductivity detector.5.2 Recorder, 1 mV, 0.5 s full-scale response.5.3 Valve Sequencer and Actuator, for switching valvecontrol.1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of Subcommit
14、teeE15.02 on Product Standards.Current edition approved Dec. 15, 2008. Published January 2009. Originallyapproved in 1995. Last previous edition approved in 2001 as E 1746-95(20011.2Thompson, B., Fundamentals of Gas Chromatography, Varian InstrumentsDivision, Sunnyvale, CA, p. 73.3Available from Sta
15、ndardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.4Available from The Chlorine Institute, Inc., 2001 L Street NW, Washington, DC20036-4919.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 10
16、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Switching Valves.5.4.1 Ten-Port Switching and Sampling Valve (stainlesssteel is acceptable).5.4.2 Four-Port Switching Valve (stainless steel is accept-able).5.5 Chromatographic Columns, 3.2-mm outside diameter,316
17、stainless, as follows:5.5.1 2 m of 80/100 mesh Porapakt N,55.5.2 0.8 m of 80/100 mesh Shimalitet Q,65.5.3 1 m of 80/100 mesh Shimalitet Q,65.5.4 0.8 m of 80/100 mesh Shimalitet Q,65.5.5 3 m of 45/60 mesh molecular sieve 5A,5.5.6 2 m of 80/100 mesh Porapakt Q,55.5.7 2 m of 80/100 mesh Porapakt N,5and
18、5.5.8 1 m of 45/60 mesh molecular sieve 5A.5.6 Tantalum Tubing, 1.6-mm outside diameter, 0.57-mminside diameter.NOTE 2Nickel tubing may be substituted for tantalum.5.7 Monelt Sampling Tube, 9.5 by 140-mm long (volume5.4 cm3).75.8 Electronic Integrator, or computer integration package.5.9 TFE-Fluoroc
19、arbon Lined Flex Tubing, 6.35 mm.5.10 TFE-Fluorocarbon Tubing, 6.35 mm by 3.05 m.5Porapakt materials, or their equivalent, have been found satisfactory for thispurpose.6Shimalitet materials, or their equivalent, have been found satisfactory for thispurpose.7Monelt material, or its equivalent, has be
20、en found satisfactory for this purpose.FIG. 1 Chlorine Impurity Analysis System Flow DiagramE17460825.11 Cajont VCR Fitting.85.12 Two-Valves, 9.5 mm, Monelt.75.13 Four-Valves, 6.35-mm tubing to 6.35-mm pipe,Monelt.75.14 Hoket Sample Cylinder, 1000 cm3, Monel, nickel,tantalum, or stainless steel.95.1
21、5 Pressure Gage, 91 kg, Monelt.75.16 Four-Pipe Tee, 6.35 mm, Monelt.75.17 Vacuum Source, suitable for chlorine disposal.6. Reagents6.1 Gas Standard, 500 g/g H2, 400 g/g O2, 800 g/g N2,50 g/g CO, and 1000 g/g CO2in argon.106.2 Argon Carrier Gas, chromatographic grade.7. Hazards7.1 Safety Precautions:
22、7.1.1 Chlorine is a corrosive and toxic material. A well-ventilated fume hood should be used to house all samplehandling and to vent the test equipment when this product isanalyzed in the laboratory.7.1.2 The analysis should be attempted only by individualswho are thoroughly familiar with the handli
23、ng of chlorine, andeven an experienced person should not work alone. Theoperator must be provided with adequate eye protection andrespirator. Splashes of liquid chlorine destroy clothing and willproduce irritations and burns if such clothing is next to theskin.7.1.3 Do not allow the sample cylinder
24、to become liquid fullif liquid samples are to be taken in cylinders. In accordancewith 49 CFR 173.304, 173.314, and 173.315, a good rule is thatthe weight of the chlorine in the cylinder should not be morethan 125 % of the weight of the water that the cylinder couldcontain.7.1.4 When sampling and wo
25、rking with chlorine out ofdoors, people downwind from such an operation should bewarned of the possible release of chlorine vapors.7.1.5 In the event that chlorine is inhaled, first aid should besummoned immediately and oxygen administered withoutdelay.7.1.6 Store pressurized samples where involunta
26、ry releasewould not cause excessive risk to people or property.7.1.7 It is recommended that means be available for thedisposal of excess chlorine in an environmentally safe andacceptable manner. A chlorine absorption system should beprovided if the chlorine cannot be disposed of in a chlorineconsumi
27、ng process. When the analysis and sampling regimenrequires an initial purging of chlorine from a container, thepurged chlorine should be handled similarly. Purging to theatmosphere should be avoided.8. Sampling8.1 Assemble the sampling apparatus as shown in Fig. 2,and purge the system with argon bef
28、ore going into the field tosample.8.2 Attach the sampling apparatus to the source of liquidchlorine to be sampled and the vacuum source.8.3 Open all valves on the sample apparatus except ValveNo. 5 on the sample bomb end opposite the gage. Evacuate thesystem using the vacuum source.8.4 Close all of
29、the valves in the system. Leave theapparatus attached to the vacuum system with the vacuumsystem on.8.5 Open the valve on the source of liquid chlorine.8.6 The following describes the cleanout of the samplingtube made from the 9.5-mm Monelt tubing:8.6.1 Open Valve No. 3 from the sample bomb to theva
30、cuum source and leave open.8.6.2 Open Valve No. 1 on the end of the sampling tubeconnected to the chlorine source for approximately 15 s.8.6.3 Close Valve No. 1.8.6.4 Slowly open Valve No. 2 on the end of the samplingtube that is connected to the sample bomb, and vent thechlorine trapped in the samp
31、ling tube into the vacuum system.8.6.5 Close Valve No. 2.8.7 Repeat 8.6-8.10 two more times so that the samplingtube has been filled and emptied a total of three times.8.8 Close Valve No. 3 between the vacuum source andsample bomb, and open Valve No. 4 on the gage end of thesample bomb.8.9 Open Valv
32、e No. 1 on the end of the sampling tubeconnected to the chlorine source for approximately 15 s.8.10 Close Valve No. 1 and open Valve No. 2 slowly.8.11 Slowly open Valve No. 3 between the sample cylinderand the vacuum source.8.12 Close Valves No. 2 and No. 3.8.13 Repeat 8.11-8.15 three more times. On
33、 the fourth timepurging the sample cylinder, do not open Valve No. 3, whichconnects the sample bomb connections to the vacuum source,but close Valve No. 4 on the gage end of the sample bomb.8.14 Close the valve on the source of the liquid chlorine.8.15 Evacuate all lines that might contain liquid ch
34、lorine byopening all valves except those on the sample bomb and liquidchlorine source. Check the pressure on the sample bomb toensure that it is below the vapor pressure of liquid chlorine atroom temperature. This ensures that only vapor chlorine ispresent in the sample bomb.8.16 Disconnect the samp
35、le bomb from the sampling appa-ratus and the sampling apparatus from the source of thechlorine. The pressure in the sample bomb should be below 54kg to contain only vapor in the bomb.8.17 This chlorine sample is now ready for analysis by thefollowing method.9. Preparation of Standards for Calibratio
36、n9.1 Obtain a custom blend of 500 g/g H2, 400 g/g O2, 800g/g N2, 50 g/g CO, and 1000 g/g CO2by volume in argonfrom a supplier of custom gas standards.8Cajont fittings, or their equivalent, have been found satisfactory for thispurpose.9Hoket sample cylinders, or their equivalent, have been found sati
37、sfactory forthis purpose.10This reagent is used for calibration only.E174608310. Column Preparation and Instrumental Parameters10.1 Remove trace components from the columns by heat-ing them overnight at 175C with 20 cm3/min argon flowingthrough them. See Fig. 1 for the correct carrier flow path tocl
38、ean the gas chromatography (GC) columns.10.2 Temperatures:Column: 75CInjection port: 110CDetector: 110C10.3 Argon Carrier Gas Flows:Reference: 20 cm3/minColumn: 20 cm3/min10.3.1 Activate the ten-port valve (the dashed line flowpath), and check the flow at the thermal conductivity detector(TCD) 1 ven
39、t. Adjust the flow to 20 cm3/min with the carriergas No. 1 pressure regulator.10.3.2 Deactivate the ten-port valve (the solid line flowpath), and activate the four-port valve (the dashed line flowpath). Check the flow at the TCD 1 vent and adjust to 20cm3/min with the carrier gas No. 2 pressure regu
40、lator.10.3.3 Activate the four-port valve (the dashed line flowpath), and adjust the flow to 20 cm3/min at the TCD 1 vent withthe auxiliary pressure regulator.10.3.4 At this point, check the flow at the end of the needlevalve restrictor and before the “T” prior to the TCD 1 detector,and adjust with
41、the restrictor needle valve to 20 cm3/min.10.4 Detector Current,80ma.10.5 Sample Size,cm3gas loop.10.6 Valve Switching Time, see Note 4.10.7 Attenuation, as needed.NOTE 3Conditions are given for a Shimadzu GC-8AIT and are shownin Fig. 1. These conditions may vary for other types of instruments. Sinc
42、ethe quality of packing material (especially molecular sieve) varies greatly,the lengths given for each of the columns in Fig. 1 are only approximate.Flow rates and column lengths are varied so as to balance the system toarrive at complete separation of the components and a stable baselineduring val
43、ve switching.NOTE 4 The exact timing will depend on the specific resistances ofthe columns used, flow rates, and column efficiencies. Timing is estab-lished by careful study of the system during setup.NOTE 5 Fig. 3 shows a typical chromatogram that can be obtainedwith this system. Hydrogen and carbo
44、n monoxide concentrations in liquidchlorine are typically at or below the detection limit of this test method.Although carbon monoxide is not shown in this chromatogram, it wouldhave a retention time after nitrogen and before carbon dioxide.11. Calibration11.1 Determine the response of each componen
45、t (O2,N2,CO, CO2, and H2) by analyzinga1cm3sample of the customlaboratory blend of these gases in argon, as outlined in Section12.FIG. 2 Chlorine Sampling ApparatusE1746084NOTE 6A 1 % commercial custom blend of the above components inargon was found to change composition after sitting several months
46、.Although more time consuming, the response factors can be determinedby analyzing the individual pure gases. This approach also eliminates theshelf life problem associated with commercially prepared standard blends.11.2 Determine the area response factors (V-s/g/g-cm3)for each component as follows:F
47、i5AiCi3 Vi(1)where:Fi= area response factor for component i,Ci= concentration of component i in the standard, g/g(volume), andVi= volume of standard injected, cm3(equal to unity when1cm3is used).NOTE 7Three runs are usually made, and the average of threedeterminations is used.12. Sample Analysis12.1
48、 Allow the chromatograph to reach the conditions listedin Section 10.12.2 Adjust the flow rates to the values indicated in Section10.12.3 Turn on the valve sequencer, and set the switchingvalves to the positions shown in Fig. 1 (dashed line flow path)with the sample system in the inject position.12.
49、4 Sample Injection:12.4.1 Turn on the argon purge through the sample system.12.4.2 Connect the sample cylinder to the sample valve asshown in Fig. 1. Argon will be purging from this connection asthe bomb is attached. Tighten the nut on the bomb fitting thatattaches the bomb to the sample valve.12.4.3 With the sample system in the inject position and theargon purge still on, break the nut connection and let argonbleed out. Retighten the nut to seal the connection. Repeat thisprocess a second time. This purges inert gases out of thesample transfer line and s
