ASTM E1746-2017a Standard Test Method for Sampling and Analysis of Liquid Chlorine for Gaseous Impurities《对液态氯进行气体杂质取样和分析的标准试验方法》.pdf

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1、Designation: E1746 17E1746 17aStandard Test Method forSampling and Analysis of Liquid Chlorine for GaseousImpurities1This standard is issued under the fixed designation E1746; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea

2、r 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 covers sampling and analysis of liquid chlorine for the determination of oxygen (200 to 400 g/g

3、), nitrogen(400 to 800 g/g), and carbon dioxide (800 to 1000 ppm) content at levels normally seen in liquid chlorine. Hydrogen and carbonmonoxide concentrations in liquid chlorine are typically at or below the detection limit of this test method.NOTE 1The minimum detection limit of hydrogen using a

4、1 cm3 gas sample and argon carrier gas is 100 to 200 g/g.2 The detection limit for theother components is significantly lower.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 Review the current Safety Data Sheets (SDS)

5、for detailed information concerning toxicity, first aid procedures, and safetyprecautions.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 practic

6、es and determine the applicability of regulatorylimitations prior to use. Specific hazards statements are given in Section 7.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Deve

7、lopment of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3D6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials

8、2.2 Code of Federal Regulations:449 CFR 173, Code of Federal Regulations Title 49, Transportation: Shippers General Requirements for Shipments andPackaging, including the following sections:173.304 Charging of Cylinders with Liquefied Compressed Gas173.314 Requirements for Compressed Gases in Tank C

9、ars173.315 Compressed Gases in Cargo Tanks and Portable Tank Containers2.3 Other Document:Chlorine Institute Pamphlet No. 1 Chlorine Basics53. Summary of Test Method3.1 A sample of liquid chlorine is trapped in a sampling tube and vaporized into a steel bomb. The vaporized chlorine in thesteel bomb

10、is introduced into a gas chromatograph by a gas sampling loop (1 cm3) using a ten-port gas sampling and switchingvalve. The separations are made on a Porapak6 Q column and on a 5A molecular sieve column whose lengths are such that thepeaks do not overlap.1 This test method is under the jurisdiction

11、of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and is the directresponsibility of Subcommittee D16.16 on Industrial and Specialty Product Standards.Current edition approved March 1, 2017July 1, 2017. Published March 2017July 2017. Originally appr

12、oved in 1995. Last previous edition approved in 20082017 as E1746 08.17. DOI: 10.1520/E1746-17.10.1520/E1746-17a.2 Thompson, B., Fundamentals of Gas Chromatography, Varian Instruments Division, Sunnyvale, CA, p. 73.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM C

13、ustomer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 Available from DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA 19111-5094, http:/quicksearch.dla.mil.5 Available from Th

14、e Chlorine Institute, Inc., 1300 Wilson Blvd., Suite 525, Arlington, VA 22209.6 Porapak is a trademark of Waters Associates, Inc.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. Be

15、causeit 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 app

16、ears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Any component that co-elutes with the components of interest may interfere with this analysis.4. Significance and Use4.1 It is very difficult to exclu

17、de sample contamination by ambient air during the process of sampling. The levels of atmosphericcontamination caused by poor sampling methods are often equal to or larger than the levels of the gaseous impurities present inthe chlorine. This results in markedly elevated levels of detected impurities

18、. As specifications become tighter, it becomes moreimportant to measure the gaseous impurity levels in liquid chlorine correctly.4.2 Additional problems are experienced in the sampling of liquefied gases for the gaseous impurities. The gaseous impuritiesreach an equilibrium between the liquid phase

19、and vapor phase in a sample bomb. The quantity of gases measured in any particularsample containing both liquid and vapor will be a function of the amount of vapor space in the sample bomb. This test methodavoids the presence of liquid in the sample bomb.5. Apparatus5.1 Gas ChromatographShimadzu GC-

20、8AITequipped as shown in Fig. 1, or equivalent, equipped with a thermal conductivityFIG. 1 Chlorine Impurity Analysis System Flow DiagramE1746 17a2detector.5.2 Recorder, 1 mV, 0.5 s full-scale response.5.3 Valve Sequencer and Actuator, for switching valve control.5.4 Switching Valves.5.4.1 Ten-Port

21、Switching and Sampling Valve (stainless steel is acceptable).5.4.2 Four-Port Switching Valve (stainless steel is acceptable).5.5 Chromatographic Columns, 3.2-mm outside diameter, 316 stainless, as follows:5.5.1 2 m of 80/100 mesh Porapak N,75.5.2 0.8 m of 80/100 mesh Shimalite Q,85.5.3 1 m of 80/100

22、 mesh Shimalite Q,85.5.4 0.8 m of 80/100 mesh Shimalite Q,85.5.5 3 m of 45/60 mesh molecular sieve 5A,5.5.6 2 m of 80/100 mesh Porapak Q,75.5.7 2 m of 80/100 mesh Porapak N,7 and5.5.8 1 m of 45/60 mesh molecular sieve 5A.5.6 Tantalum Tubing, 1.6-mm outside diameter, 0.57-mm inside diameter.NOTE 2Nic

23、kel tubing may be substituted for tantalum.5.7 Monel Sampling Tube, 9.5 by 140-mm long (volume 5.4 cm3).95.8 Electronic Integrator, or computer integration package.5.9 TFE-Fluorocarbon Lined Flex Tubing, 6.35 mm.5.10 TFE-Fluorocarbon Tubing, 6.35 mm by 3.05 m.5.11 Cajon VCR Fitting. 105.12 Two-Valve

24、s, 9.5 mm, Monel.95.13 Four-Valves, 6.35-mm tubing to 6.35-mm pipe, Monel.95.14 Hoke11 Sample Cylinder, 1000 cm3, Monel,9 nickel, tantalum, or stainless steel.5.15 Pressure Gage, 91 kg, Monel.95.16 Four-Pipe Tee, 6.35 mm, Monel.95.17 Vacuum Source, suitable for chlorine disposal.6. Reagents6.1 Gas S

25、tandard, 500 g/g H2, 400 g/g O2, 800 g/g N2, 50 g/g CO, and 1000 g/g CO2 in argon.126.2 Argon Carrier Gas, chromatographic grade.7. Hazards7.1 Safety Precautions:7.1.1 Chlorine is a corrosive and toxic material. A well-ventilated fume hood should be used to house all sample handling andto vent the t

26、est equipment when this product is analyzed in the laboratory.7.1.2 The analysis should be attempted only by individuals who are thoroughly familiar with the handling of chlorine, and evenan experienced person should not work alone. The operator must be provided with adequate eye protection and resp

27、irator. Splashesof liquid chlorine destroy clothing and will produce irritations and burns if such clothing is next to the skin.7.1.3 Do not allow the sample cylinder to become liquid full if liquid samples are to be taken in cylinders. In accordance with49 CFR 173.304, 173.314, and 173.315, a good

28、rule is that the weight of the chlorine in the cylinder should not be more than 125 %of the weight of the water that the cylinder could contain.7.1.4 When sampling and working with chlorine out of doors, people downwind from such an operation should be warned ofthe possible release of chlorine vapor

29、s.7.1.5 In the event that chlorine is inhaled, first aid should be summoned immediately and oxygen administered without delay.7 Porapak materials, or their equivalent, have been found satisfactory for this purpose.8 Shimalite, a trademark of Shimadzu Seisakusho Ltd., Japan, materials or their equiva

30、lent, have been found satisfactory for this purpose.9 Monel, a trademark of Special Metals Corporation, material or its equivalent, has been found satisfactory for this purpose.10 Cajon, a trademark of Swagelok Company, fittings or their equivalent, have been found satisfactory for this purpose.11 H

31、oke, registered trademark of Hoke Inc., sample cylinders, or their equivalent, have been found satisfactory for this purpose.12 This reagent is used for calibration only.E1746 17a37.1.6 Store pressurized samples where involuntary release would not cause excessive risk to people or property.7.1.7 It

32、is recommended that means be available for the disposal of excess chlorine in an environmentally safe and acceptablemanner. A chlorine absorption system should be provided if the chlorine cannot be disposed of in a chlorine consuming process.When the analysis and sampling regimen requires an initial

33、 purging of chlorine from a container, the purged chlorine should behandled similarly. Purging to the atmosphere should be avoided.8. Sampling8.1 Assemble the sampling apparatus as shown in Fig. 2, and purge the system with argon before going into the field to sample.8.2 Attach the sampling apparatu

34、s to the source of liquid chlorine to be sampled and the vacuum source.8.3 Open all valves on the sample apparatus except Valve No. 5 on the sample bomb end opposite the gage. Evacuate the systemusing the vacuum source.8.4 Close all of the valves in the system. Leave the apparatus attached to the va

35、cuum system with the vacuum system on.8.5 Open the valve on the source of liquid chlorine.8.6 The following describes the cleanout of the sampling tube made from the 9.5-mm Monel9 tubing:8.6.1 Open Valve No. 3 from the sample bomb to the vacuum source and leave open.8.6.2 Open Valve No. 1 on the end

36、 of the sampling tube connected 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 sampling tube that is connected to the sample bomb, and vent the chlorinetrapped in the sampling tube into the vacuum system.8.6.5 Close Valve No. 2.8

37、.7 Repeat 8.6 8.10 two more times so that the sampling tube has been filled and emptied a total of three times.8.8 Close Valve No. 3 between the vacuum source and sample bomb, and open Valve No. 4 on the gage end of the sample bomb.8.9 Open Valve No. 1 on the end of the sampling tube connected to th

38、e chlorine source for approximately 15 s.FIG. 2 Chlorine Sampling ApparatusE1746 17a48.10 Close Valve No. 1 and open Valve No. 2 slowly.8.11 Slowly open Valve No. 3 between the sample cylinder and the vacuum source.8.12 Close Valves No. 2 and No. 3.8.13 Repeat 8.11 8.15 three more times. On the four

39、th time purging 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 chlorine

40、by opening all valves except those on the sample bomb and liquidchlorine source. Check the pressure on the sample bomb to ensure that it is below the vapor pressure of liquid chlorine at roomtemperature. This ensures that only vapor chlorine is present in the sample bomb.8.16 Disconnect the sample b

41、omb from the sampling apparatus and the sampling apparatus from the source of the chlorine. Thepressure in the sample bomb should be below 54 kg to contain only vapor in the bomb.8.17 This chlorine sample is now ready for analysis by the following method.9. Preparation of Standards for Calibration9.

42、1 Obtain a custom blend of 500 g/g H2, 400 g/g O2, 800 g/g N2, 50 g/g CO, and 1000 g/g CO2 by volume in argon froma supplier of custom gas standards.10. Column Preparation and Instrumental Parameters10.1 Remove trace components from the columns by heating them overnight at 175C with 20 cm3/min argon

43、 flowing throughthem. See Fig. 1 for the correct carrier flow path to clean the gas chromatography (GC) columns.10.2 Temperatures:FIG. 3 Chromatogram of the Gaseous Impurities in ChlorineE1746 17a5Column: 75CInjection port: 110CDetector: 110C10.3 Argon Carrier Gas Flows:Reference: 20 cm3/minColumn:

44、20 cm3/min10.3.1 Activate the ten-port valve (the dashed line flow path), and check the flow at the thermal conductivity detector (TCD)1 vent. Adjust the flow to 20 cm3/min with the carrier gas No. 1 pressure regulator.10.3.2 Deactivate the ten-port valve (the solid line flow path), and activate the

45、 four-port valve (the dashed line flow path). Checkthe flow at the TCD 1 vent and adjust to 20 cm3/min with the carrier gas No. 2 pressure regulator.10.3.3 Activate the four-port valve (the dashed line flow path), and adjust the flow to 20 cm3/min at the TCD 1 vent with theauxiliary pressure regulat

46、or.10.3.4 At this point, check the flow at the end of the needle valve restrictor and before the “T” prior to the TCD 1 detector, andadjust with the restrictor needle valve to 20 cm3/min.10.4 Detector Current, 80 ma.10.5 Sample Size, cm3 gas loop.10.6 Valve Switching Time, see Note 4.10.7 Attenuatio

47、n, as needed.NOTE 3Conditions are given for a Shimadzu GC-8AIT and are shown in Fig. 1. These conditions may vary for other types of instruments. Since mayvary since the quality of packing material (especially molecular sieve) varies greatly, the lengths given for each of the columns in Fig. 1 are o

48、nlyapproximate. Flow rates and column lengths are varied so as to balance the system to arrive at complete separation of the components and a stable baselineduring valve switching. Detector current and attenuation may need to be adjusted to obtain the required sensitivity.NOTE 4The exact timing will

49、 depend on the specific resistances of the columns used, flow rates, and column efficiencies. Timing is established bycareful study of the system during setup.NOTE 5Fig. 3 shows a typical chromatogram that can be obtained with this system. Hydrogen and carbon monoxide concentrations in liquid chlorineare typically at or below the detection limit of this test method. Although carbon monoxide is not shown in this chromatogram, it would have a retentiontime after nitrogen and before carbon dioxide.11. Calibration11.1 Determine the response of each co