1、Designation: E 1754 95 (Reapproved 2001)e1Standard Test Method forDetermination of Low Levels of Water in Liquid Chlorine ByInfrared Spectrophotometry1This standard is issued under the fixed designation E 1754; the number immediately following the designation indicates the year oforiginal adoption o
2、r, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial changes were made in August 2001.1. Scope1.1 This test method covers the
3、determination of the contentof water in liquid chlorine in the concentration range of 0.5 to15 mg/kg (ppm).1.2 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 a
4、nd health practices and determine the applica-bility of regulatory limitations prior to use. See Section 7 forspecific hazards statements.1.3 Review the current Material Safety Data Sheets (MSDS)for detailed information concerning toxicity, first aid proce-dures, and safety precautions.2. Referenced
5、 Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemicals3E 806 Test Method for Carbon Tetrachloride and Chloro-form in Liquid Chlorine by Direct Injection (Gas Chro-matographic Pro
6、cedure)32.2 Federal Standards:449 CFR 173 Code of Federal Regulations Title 49 Trans-portation: Shippers General Requirements for Shipmentsand Packaging, including Sections:173.304 Charging of Cylinders with Liquefied CompressedGas173.314 Requirements for Compressed Gases in Tank Cars173.315 Compres
7、sed Gases in Cargo Tanks and PortableTank Containers3. Summary of Test Method3.1 A sample of liquid chlorine is introduced into a specialinfrared cell and maintained as a liquid under its own pressure.A spectrometer scans from 400 to 4400 wavenumbers of theinfrared transmission spectrum of liquid ch
8、lorine. This spec-trum is then ratioed to one obtained of the nitrogen-filledinfrared cell previously. The ratioed spectrum is converted toabsorbance, and the net absorbance of the water band at 1596wavenumbers, relative to a reference at 1663 wavenumbers, isdetermined. The amount of water correspon
9、ding to this netabsorbance is determined from a calibration curve preparedfrom the infrared absorbances of standards that contain knownconcentrations of water in liquid chlorine.4. Significance and Use4.1 Trace amounts of water may be detrimental to the use ofchlorine in some applications. The amoun
10、t of water in thechlorine must be known to prevent problems during its use.5. Apparatus5.1 Infrared Spectrometer, capable of measurements in the1600 wavenumber region. An FTIR with 4 wavenumberresolution is the instrument of choice, but dispersive instru-ments may also be used to achieve similar res
11、ults.5.2 Special Infrared Cell (see Fig. 1), neither cell size norpathlength are critical to the analysis, but sensitivity and limitof detection are dependent on pathlength. The concentrationrange reported in the scope is achievable with a 60-mmpathlength cell constructed with:5.2.1 Hastelloy C and
12、316 Stainless Steel Stock, suitable formachining.51This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicalsand is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Sept. 10, 1995. Published December 1995.2Annual
13、 Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 15.05.4Available from Superintendent of Documents, Government Printing Office,Washington, DC 20402.5Available from Collins Instrument Co. Inc., P.O. Drawer 938 Angleton, TX77516-0938.1Copyright ASTM, 100 Barr Harbor Drive, West C
14、onshohocken, PA 19428-2959, United States.5.2.2 Silver Chloride Windows, 0.5 by 2.5 cm.6FIG. 1(a) Pipe AdapterFIG. 1(b) Air Cap Detail6Available from Harshaw Chemical Co., 6801 Cochran Road, Solon, OH 44139.NOTE 1Drawing not to scale.FIG. 1 Infrared CellE 17542FIG. 1(c) Body DetailFIG. 1(d) Gasket D
15、etailFIG. 1(e) Insert DetailFIG. 1(f) Flange Detail5.2.3 Perfluoroelastomer Sheet, 0.030 in. thickness.75.3 Ball Valves, Monel14 in. valve with pipe and14 in. tubeends.5.4 Needle Valves, nickel or Monel14 in. valve with pipeand14 in. tube ends.5.5 Sample Cylinder Assembly (see Fig. 2), consisting of
16、:5.5.1 Sample Cylinder, nickel, Monel, or tantalum; 400 to1000 mL capacity, double-ended, with valves at each end,specially cleaned. Cylinders with both valves at one end andwith a dip tube on one valve have been found to be satisfactory.Another option is to construct special cylinders containing as
17、eptum fitting on one end.NOTE 1A procedure for cleaning cylinders and valves, for use withliquid chlorine, is given in Test Method E 806, Appendix X2.5.5.2 Needle and Ball Valve, nickel body, having packingresistant to liquid chlorine.8If nickel valves are not available,Monel valves may be used.7Ava
18、ilable from I.E. DuPont de Nemours and Co., Wilmington, DE 19898.8Packing made from TEFLONt, VITONt, or KEL-Ft has been found satisfac-tory for this purpose.E 175435.5.3 Septum, inserted into a14 in. nut.5.5.4 Glove Bag or Dry Box, purged with dry nitrogen (lessthan 5 ppm water vapor).5.5.5 Fittings
19、, for transferring chlorine from one cylinder toanother.5.5.6 0to10L Syringe and 0 to 25 L Syringe, 26 gageneedle.5.5.7 Dewar Flask, of sufficient size to hold a cylindersurrounded by dry ice and methylene chloride. The Dewarflask should be supported by a wooden holder for safetypurposes.5.5.8 Hygro
20、meter, capable of measuring moisture as low as5 ppm in glove bag or dry box.5.6 Silicone Rubber Septa.5.7 Mechanical Shaker.5.8 Drying Oven.6. Reagents6.1 Chlorine, liquid with less than 5 ppm water.6.2 Methylene Chloride (CH2Cl2).96.3 Dry Ice (CO2).6.4 Dry Nitrogen, (5 ppm water) to purge glove bag
21、 or drybox and test equipment.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 test equip-ment, except the infrared spectrophotometer, when this mate-rial is analyzed in the laboratory.7.1.2 The analysis should
22、 be attempted only by persons whoare thoroughly familiar with the handling of chlorine, and evenan experienced person should not work alone. The analyst mustbe provided with adequate eye protection (chemical gogglesare recommended) and an approved chlorine respirator.Splashes of liquid chlorine dest
23、roy clothing and if suchclothing is next to the skin, will produce irritation and burns.7.1.3 When sampling and working with chlorine out ofdoors, people downwind from such operations should bewarned of the possible release of chlorine.7.1.4 It is recommended that means be available for disposalof e
24、xcess chlorine in an environmentally safe and acceptablemanner. If chlorine cannot be disposed of in a chlorineconsuming process, a chlorine absorption system should beprovided. When the analysis and sampling regimen requires aninitial purging of chlorine from a container, the purged chlorineshould
25、be similarly handled. Purging to the atmosphere shouldbe avoided.7.1.5 In the event chlorine is inhaled, first aid should besummoned immediately.8. Sampling8.1 Sampling points should also be chosen with care.Ensure that the sample point is associated with flowingchlorine, and is not near a“ dead leg
26、” where the concentrationsof impurities in the chlorine will never change because thechlorine never moves. If sampling through secondary piping,that piping should be purged well with nitrogen or dry airbefore being blocked in. Otherwise, temperature variations canresult in water vapor condensing ins
27、ide the piping to contami-nate the chlorine sample when it is grabbed. Finally, samplingshould be done at a sample point representative of the chlorineneeding to be analyzed.8.1.1 Sampling from tank cars, barges, storage tanks, andlarge cylinders presents unique problems. Each facility, how-ever, mu
28、st be capable of delivering a liquid sample (not gas).Acceptable samples can be obtained by sampling in accordance9This reagent is used for cooling purposes only.FIG. 2 Sample Cylinder AssemblyE 17544with the Chlorine Institute Pamphlet No. 77, “Sampling LiquidChlorine”.108.2 It is recommended that
29、samples be collected from thesefacilities in the sample cylinder assembly listed in 5.5. Properand safe sampling techniques must be followed. The cylindermust contain at least 75 % by volume of liquid chlorine (lessthan 25 % vapor space).NOTE 2Do not allow the cylinder to become liquid full. Tare th
30、ecylinder, fill with water, and re-weigh to determine the weight of water inthe cylinder. Multiply this weight by 1.56 (the assumed specific gravity ofliquid chlorine) and by 0.75 to obtain the weight of chlorine to fill thecylinder 75 % full. Example: The cylinder holds 1000 g of water (1000mL, ass
31、uming a specific gravity of 1.0). The filled cylinder will hold 1560g of chlorine, and at 75 % of capacity, it will contain 1170 g of chlorine.8.3 The sample cylinders should be thoroughly dried byplacing in an oven at 105C for at least6horpreferablyovernight; the dip tubes are not heated, place the
32、m in adesiccator. Valves are also placed in the oven, but not as a partof the cylinder (packings are resistant to this temperature).After this treatment, the cylinders are cooled with plant air orN2having 5 ppm moisture. The valves are removed, placed ina desiccator with a suitable drying agent, and
33、 cooled to roomtemperature.9. Preparation of Standards for Calibration9.1 Obtain four clean, evacuated sample cylinders. Onlycylinders that have been properly pressure-tested should beused. Equip three with a ball valve and a needle valve, labelthese Cylinders No. 2 through No. 4 and record weight t
34、o thenearest gram. Equip the fourth cylinder with two needle valves,weigh to the nearest gram, record, and label as No. 1. Once itcontains chlorine, it will be used to purge the infrared cellbefore standards are loaded. Use caps on all valves. If dip tubesare used, attach the dip tube to the needle
35、valve. Check thehygrometer to make sure the atmosphere in the glove bag ordry box contains 5 ppm moisture before performing anytransfers of chlorine.9.2 Load the four cylinders with liquid chlorine. The liquidchlorine should contain less than 5 ppm water. All cylindersmust contain at least 75 % by v
36、olume liquid chlorine (less than25 % vapor space). All cylinders should be weighed to thenearest gram and recorded to determine the weight of chlorinein each cylinder (Note 2). Place the filled cylinders into theglove bag or dry box inside the hood. Place all fittings, toolsand equipment, including
37、the purged infrared cell, in the glovebag or dry box. Wait until the hygrometer in the glove bag ordry box is reading 5 ppm moisture before proceeding.9.3 Remove the cap on Valve A of Cylinder No. 1 and blowwith N2to remove any trapped moisture. Do this each time aconnection is made. Then connect th
38、e cylinder and the specialinfrared cell to the filling apparatus (see Fig. 2) in such a waythat the liquid chlorine will flow into the cell and that thevalves on all parts of the apparatus are closed prior to filling thecell. For the following operations, refer to 7.1.4 on ventingchlorine.9.4 Open V
39、alve F and then Valve A. Flush the fillingapparatus by partially opening Valve B for a few seconds andthen closing it. Leave Valve A open.9.4.1 Open Valves E and C. Flush the cell by partiallyopening Valve D and observing flow, then close Valve C andthen Valve D.9.5 Fill the infrared cell by opening
40、 Valve C and observe thefilling of the cell windows. Close Valve C and empty the cellby opening Valve D. Close Valve D.9.6 Fill and empty the cell once more, as above.9.6.1 Close Valve A and open Valve B, to purge the fillingapparatus, then close.9.7 Remove the cylinder. Connect Cylinder No. 2 to th
41、efilling apparatus after blowing Valve A with N2. Make sure thatthe cylinder is connected to the apparatus in such a way that theliquid chlorine will flow into the cell and that the valves on allparts of the apparatus are closed prior to attempting to fill thecell. For the following operations, refe
42、r to 7.1.4 on ventingchlorine. Repeat 9.4 to 9.6.9.8 Fill the cell by opening Valve C. Close Valve C andinvert the cell to ensure complete filling of the cell window andthen close Valve A.9.9 Vent the residual chlorine from the filling apparatus byopening Valve B and then open Valve C a little and d
43、ump asmall amount of chlorine from the inverted cell, then quicklyclose. The cell window should have about15 vapor space wheninverted. Then close Valves B and E.9.10 Allow the cell to come to ambient temperature. Beforeremoving the cell from the filling apparatus, check again foradequate vapor space
44、 in the inverted cell window. If no vaporspace is seen, open Valve B and quickly open and close ValveC a little to dump some more chlorine. Make sure that no morethan14to15 of the cell window is vapor space when the cell isinverted. Remove Cylinder No. 1 and No. 2 and record theirweights.9.11 Place
45、the infrared cell in the spectrometer and scan intransmission mode from 400 to 4400 wavenumbers at4-wavenumber resolution. Ratio this spectrum to a spectrumtaken of the infrared cell filled with nitrogen. Then convert theratioed transmission spectrum to absorbance and measure thenet absorbance of th
46、e band at 1596 wavenumber relative to areference at 1663 wavenumbers.9.12 Repeat the operations above (9.4-9.11, omit 9.6.1) withchlorine Cylinders No. 3 and No. 4.9.13 Low concentrations of water will be present in eachcylinder prior to introduction of additional water via a microli-tre syringe. In
47、frared absorbance spectra of the three cylindersof liquid chlorine obtained at the same time should agreewithin 20 %. For example, absorbance of water at 1596 cm-1less the reference at 1663 cm-1for Cylinder No. 1 yields a peakheight of 25 mAU. The same measurement for Cylinder No. 2is 30 mAU, and fo
48、r Cylinder No. 3 is 20 mAU.9.14 Add approximately 500 mL of methylene chloride tothe Dewar flask supported by a wooden holder. Add smallpieces of dry ice to the Dewar flask, then place the woodenholder and Dewar flask in the glove bag or dry box.9.15 To prevent overflowing the Dewar flask, slowly lo
49、werCylinder No. 2 into the methylene chloride/dry ice mixture for10Available from The Chlorine Institute, Inc., 2001 L St. NW, Washington, DC20036.E 17545cooling. The mixture should cover about23of the cylinder.9.16 Calculate the volume of water in microlitres to add tothe cylinder to increase the water in the chlorine 5 mg/kg. Usethe weight of the cylinder after filling the cell to determine theweight of the chlorine remaining in the cylinder. Assume thedensity of water to be 1.0 g/mL.9.17 In the glove bag or dry box, fill the 10-L syringe withthe volume of water calcula
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