1、Designation: E1786 08E1786 17Standard Test Method forDetermination of Low Levels of Water in Liquid Chlorine byOn-Line Infrared Spectrophotometry1This standard is issued under the fixed designation E1786; the number immediately following the designation indicates the year oforiginal adoption or, in
2、the 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. Scope*1.1 This test method is designed for the on-line determination of the content of water
3、in liquid chlorine in the concentrationrange of 0.5 to 15 mg/kg (ppm).1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.3 Review the current Material Safety Data Sheets (MSDS)(SDS) for detailed information concerning toxicity
4、, first aidprocedures, and safety precautions.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 applicability of regula
5、torylimitations prior to use. Specific hazards statements are given in Section 7 and Note 3.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE806 Test Method for Carbon Tetrachloride and Chloroform in Liquid Chlorine by Direct Injection (Gas ChromatographicProcedure)2.
6、2 Federal Standards:349 CFR 173 Code of Federal Regulations Title 49 Transportation: ShippersShippersGeneral Requirements for Shipments andPackaging, including the following sections:173.304 Charging of Cylinders with Liquefied Compressed Gas173.314 Requirements for Compressed Gases in Tank Cars173.
7、315 Compressed Gases in Cargo Tanks and Portable Tank Containers2.3 Other Document:4Chlorine Institute Pamphlet No. 771 Sampling Liquid Chlorine Chlorine Basics3. Summary of Test Method3.1 Liquid chlorine continuously flows through a special infrared cell where it is maintained as a liquid under its
8、 own pressure.A process infrared spectrometer scans from 400 to 4400 wavenumbers of the infrared transmission spectrum of liquid chlorine.This spectrum then is ratioed to one obtained from the nitrogen-filled infrared cell previously. The ratioed spectrum is convertedto absorbance, and the net absor
9、bance of water band at 1596 wavenumbers, relative to a reference at 1663 wavenumbers, isdetermined.3.2 The amount of water corresponding to this net absorbance is determined from a calibration curve prepared from the infraredabsorbencies of standards which contain concentrations of water in liquid c
10、hlorine. These standards are prepared from manual1 This test method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of SubcommitteeD16.16 on Industrial and Specialty Product Standards.Current edition approved April 1, 20
11、08March 1, 2017. Published May 2008March 2017. Originally approved in 1996. Last previous edition approved in 20022008 asE1786 02.E1786 08. DOI: 10.1520/E1786-08.10.1520/E1786-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org.
12、For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Code of Federal Regulations, availableAvailable from U.S. Government Printing Office, Washington, DC 20402.Superintendent of Documents, 732 N. Capitol St., NW,Washington, DC 20401-
13、0001, http:/www.access.gpo.gov.4 Available from The Chlorine Institute, Inc., 2001 L St. NW, Washington, DC 20036-4919.1300 Wilson Blvd., Suite 525, Arlington, VA 22209, https:/www.chlorineinstitute.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standar
14、d an indication of what changes have been made to the previous version. Becauseit 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 i
15、s to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1samples of liquid chlorine in tantalum cylinders. Sample from each cylinder is i
16、ntroduced into a calibration infrared cell andmaintained as a liquid under its own pressure.4. Significance and Use4.1 Trace amounts of water may be detrimental to the use of chlorine in some applications. The amount of water in the chlorinemust be known to prevent problems during its use.5. Apparat
17、us5.1 Process Infrared Spectrometer, capable of measurements in the 1600 wavenumber region. An FTIR with four wavenumberresolution is the instrument of choice, but dispersive instruments also may be used to achieve similar results.5.2 Special Infrared Calibration Cell (Fig. 1), as used for calibrati
18、on. Neither cell size nor pathlength are critical to the analysis,but sensitivity and limit of detection are dependent on pathlength. The concentration range reported in the Section 1 is achievablewith a 60-mm pathlength cell constructed with the following: Figs. 2-75.2.1 Hastelloy C and 316 Stainle
19、ss Steel Stock, suitable for machining,5.2.2 Silver Chloride Windows, 0.5 cm 2.5 cm, and5.2.3 Perfluoroelastomer Sheet, 0.762 mm (0.030 in.) thickness.5.3 Ball Valves, Monel 6.35 mm (14-in.) valve with pipe and 6.35 mm (14-in.) tube ends.5.4 Needle Valves, Nickel or Monel 6.35 mm (14-in.) valve with
20、 pipe and 6.35 mm (14-in.) tube ends.5.5 Sample Cylinder Assembly (Fig. 8), consisting of:5.5.1 Sample Cylinder, nickel, Monel, or tantalum, 400 to 1000-mL capacity, double-ended, with valves at each end, speciallycleaned. Cylinders with both valves at one end and with a dip tube on one valve have b
21、een found to be satisfactory.Another optionis to construct special cylinders containing a septum fitting on one end.NOTE 1A procedure for cleaning cylinders and valves, for use with liquid chlorine, is given in Test Method E806, Appendix X2 .X2.FIG. 1 Infrared Cell (Drawing Not to Scale)E1786 1725.5
22、.2 One Needle and One Ball Valve, nickel body, having packing resistant to liquid chlorine. If nickel valves are not available,monel valves may be used.5.5.3 Septum, inserted into a 6.35 mm (14-in.)-in. nut.5.5.4 Glove Bag or Dry Box, purged with dry nitrogen (less than 5 mg/kg (ppm) water vapor).5.
23、5.5 Fittings, for transferring chlorine from one cylinder to another.5.5.6 One 0 to 10 L Syringe and One 0 to 25 L Syringe, 26 gage needle.5.5.7 Dewar Flask, of sufficient size to hold a cylinder surrounded by dry ice and methylene chloride. The Dewar flask shouldbe supported by a wooden holder for
24、safety purposes.5.5.8 Hygrometer, capable of measuring moisture as low as 5 mg/kg (ppm) in glove bag or dry box.5.6 Silicone Rubber Septa.5.7 Mechanical Shaker.5.8 Drying Oven.FIG. 2 Pipe AdapterFIG. 3 Air Cap DetailE1786 1735.9 Special Infrared Process Cell (Fig. 9) for on-line analysis of water in
25、 liquid chlorine. Neither cell size nor path length iscritical to the analysis, but sensitivity and limit of detection are dependent on pathlength. The concentration range reported in thescope is achievable with a 60-mm pathlength cell constructed with:5.9.1 Hastelloy C and 316 Stainless Steel Stock
26、, suitable for machining.5.9.2 Silver Chloride Windows, two, 25-mm diameter by 2-mm thick and two 25-mm diameter by 4-mm thick.5.9.3 Eight Viton O-rings, Size 027.FIG. 4 Body DetailFIG. 5 Gasket DetailE1786 1746. Reagents6.1 Purity of WaterUnless otherwise indicated, water means Type II or III reage
27、nt water conforming to Specification D1193.6.2 Chlorine, liquid with less than 5 mg/kg (ppm) water.6.3 Methylene Chloride (CH2Cl2).NOTE 2This reagent is used for cooling purposes only.6.4 Dry Ice (CO2).6.5 Dry Nitrogen (5 mg/kg (ppm) water), to purge glove bag or dry box and test equipment.7. Hazard
28、s7.1 Safety Precautions:7.1.1 Chlorine is a corrosive and toxic material. Use a well-ventilated fume hood to house all test equipment, except the infraredspectrophotometer, when this material is analyzed in the laboratory.FIG. 6 Insert DetailFIG. 7 Flange DetailE1786 1757.1.2 Persons who are thoroug
29、hly familiar with the handling of chlorine should perform this analysis. An experienced personshould not work alone. The analyst must be provided with adequate eye protection (chemical goggles are recommended) and anapproved chlorine respirator. Splashes of liquid chlorine destroy clothing, and if s
30、uch clothing is next to the skin, will produceirritation and burns.7.1.3 When sampling and working with chlorine out of doors, warn people downwind from such operations of the possiblerelease of chlorine.7.1.4 Dispose of excess chlorine in an environmentally safe and acceptable manner. If chlorine c
31、annot be disposed of in achlorine consuming process, provide a chlorine absorption system. When the analysis and sampling regimen requires an initialpurging of chlorine from a container, the purged chlorine should be similarly handled. Avoid purging to the atmosphere.FIG. 8 Sample Cylinder AssemblyF
32、IG. 9 Special Infrared Process CellE1786 1767.1.5 In the event chlorine is inhaled, use first aid immediately.8. Sampling for Calibration Standards8.1 Carefully choose sampling points. Ensure that the sample point is associated with flowing chlorine and is not near a “deadleg” where the concentratio
33、ns of impurities in the chlorine will never change because the chlorine never moves. If samplingthrough secondary piping, purge that piping well with nitrogen or dry air before being blocked in. Otherwise, temperaturevariations can result in water vapor condensing inside the piping to contaminate th
34、e chlorine sample when it is grabbed.8.1.1 Finally, perform sampling at a sample point representative of the chlorine needing to be analyzed; that is, sample purechlorine after all purification steps, drying steps, and so forth, to ensure that the analytical results are meaningful.8.1.1.1 Sampling f
35、rom tank cars, barges, storage tanks, and large cylinders presents unique problems. Each facility, however,must be capable of delivering a liquid sample (not gas). Acceptable samples can be obtained by sampling in accordance with theSee Chlorine Institute Pamphlet No. 77.1. (See 49 CFR 173, includin
36、g Parts 173.304, 173.314, and 173.315.)8.2 Collect samples from these facilities in the sample cylinder assembly listed in 6.5. Follow proper and safe samplingtechniques. The cylinder must contain at least 75 % by volume of liquid chlorine (less than 25 % vapor space).NOTE 3Do not allow the cylinder
37、 to become liquid-full.Tare the cylinder, fill with water, and reweigh to determine the weight of water in the cylinder.Multiply this weight by 1.56 (the assumed specific gravity of liquid chlorine) and by 0.75 to obtain the weight of chlorine to fill the cylinder 75 % full.For example, the cylinder
38、 holds 1000 g of water (1000 mL, assuming a specific gravity of 1.0). The filled cylinder will hold 1560 g of chlorine, and at75 % of capacity, it will contain 1170 g of chlorine.8.3 Thoroughly dry the sample cylinders by placing them in an oven at 105C for at least 6 h or preferably overnight. Theu
39、nheated dip tubes are placed in a desiccator. Valves also are placed in the oven but not as a part of the cylinder (packings areresistant to this temperature). After this treatment, the cylinders are cooled with plant air or N2 having 5 mg/kg (ppm) moisture.The valves are removed, placed in a desicc
40、ator with a suitable drying agent, and cooled to room temperature.9. Preparation of Standards for Calibration9.1 Obtain four clean, evacuated sample cylinders. Use only cylinders that have been properly pressure-tested. Equip three witha ball valve and a needle valve, label these Cylinders No. 2 thr
41、ough No. 4, and record weight to the nearest gram. Equip the fourthcylinder with two needle valves, weigh to the nearest gram, record, and label No. 1. Once it contains chlorine, it will be used topurge the infrared cell before standards are loaded. Use caps on all valves. If dip tubes are used, att
42、ach the dip tube to the needlevalve. Check the hygrometer to make sure the atmosphere in the glove bag or dry box contains 5 mg/kg (ppm) moisture beforeperforming any transfers of chlorine.9.2 Load the four cylinders with liquid chlorine. The liquid chlorine should contain less than 5 mg/kg (ppm) wa
43、ter.All cylindersmust contain at least 75 % by volume of liquid chlorine (less than 25 % vapor space). All cylinders should be weighed to thenearest gram and recorded to determine the weight of chlorine in each cylinder (Note 3). Place the filled cylinders into the glovebag or dry box inside the hoo
44、d. Place all fittings, tools and equipment, including the purged infrared cell, in the glove bag or drybox. Wait until the hygrometer in the glove bag or dry box is reading 5 mg/kg (ppm) moisture before proceeding.9.3 Remove the cap on Valve A of Cylinder No. 1 and blow with N2 to remove any trapped
45、 moisture. Do this each time aconnection is made. Then connect the cylinder and the special infrared cell to the filling apparatus (Fig. 8) in such a way that theliquid chlorine will flow into the cell and the valves on all parts of the apparatus are closed prior to filling the cell. For the followi
46、ngoperations, refer to 7.4 on venting chlorine.9.4 Open Valve F and then Valve A. Flush the filling apparatus by partially opening Valve B for a few s and then closing it.Leave Valve A open.9.4.1 Open Valves E and C. Flush the cell by partially opening Valve D and observing flow, then close Valve C
47、and then ValveD.9.5 Fill the infrared cell by opening Valve C and observe the filling of the cell windows. Close Valve C and empty the cell byopening Valve D. Close Valve D.9.6 Fill and empty the cell once more, as described above.9.6.1 Close Valve A and open Valve B, to purge the filling apparatus,
48、 then close.9.7 Remove the cylinder. Connect Cylinder No. 2 to the filling apparatus after blowing Valve A with N2. Make sure that thecylinder is connected to the apparatus in such a way that the liquid chlorine will flow into the cell and that the valves on all partsof the apparatus are closed prio
49、r to attempting to fill the cell. For the following operations, refer to 7.47.1.4 on venting chlorine.Repeat 9.4 9.6.9.8 Fill the cell by opening Valve C. Close Valve C and invert the cell to ensure complete filling of the cell window and thenclose Valve A.E1786 1779.9 Vent the residual chlorine from the filling apparatus by opening Valve B and then open Valve C a little and dump a smallamount of chlorine from the inverted cell, then quickly close. The cell window should have about 15 vapor space when inverted.Then close Valves B and E.9.10 Allow
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