1、Designation: E 1754 08Standard 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 or, in the case of re
2、vision, 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.1. Scope*1.1 This test method covers the determination of the contentof water in liquid chlorine in the conce
3、ntration range of 0.5 to15 mg/kg (ppm).1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the
4、 user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. See Section 7 forspecific hazards statements.1.4 Review the current Material Safety Data Sheets (MSDS)for detailed information concerning toxicity, fi
5、rst aid proce-dures, and safety precautions.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE 806 Test Method for Carbon Tetrachloride and Chloro-form in Liquid Chlorine by Direct Injection (Gas Chro-matographic Procedure)2.2 Federal Standards:349 CFR 173 Code of Fed
6、eral 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 Compressed Gases in Cargo Tanks and PortableTank Containers3
7、. 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 chlorine. This spec-trum is then ratioed to one obtaine
8、d 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 corresponding to this netabsorbance is determined from a calib
9、ration 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 amount of water in thechlorine must be known to prevent pr
10、oblems 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 results.5.2 Special Infrared Cell (see Fig. 1), neither
11、cell size norpathlength are critical to the analysis, but sensitivity and limitof detection are dependent on pathlength. The concentration1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.02 on P
12、roduct Standards.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1995. Last previous edition approved in 2001 as E175495(2001)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
13、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Superintendent of Documents, Government Printing Office,Washington, DC 20402.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr
14、 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.range reported in the scope is achievable with a 60-mmpathlength cell constructed with:5.2.1 Hastelloy C and 316 Stainless Steel Stock, suitable formachining.5.2.2 Silver Chloride Windows, 0.5 by 2.5 cm.FIG. 1(a) Pipe Adapte
15、rNOTE 1Drawing not to scale.FIG. 1 Infrared CellE 1754 082FIG. 1(b) Air Cap DetailFIG. 1(c) Body DetailFIG. 1(d) Gasket DetailFIG. 1(e) Insert DetailFIG. 1(f) Flange DetailE 1754 0835.2.3 Perfluoroelastomer Sheet, 0.030 in. thickness.5.3 Ball Valves, Monel14 in. valve with pipe and14 in. tubeends.5.
16、4 Needle Valves, nickel or Monel 6.35 mm (14 in.) valvewith pipe and 6.35 mm (14 in.) tube ends.5.5 Sample Cylinder Assembly (see Fig. 2), consisting of:5.5.1 Sample Cylinder, nickel, Monel, or tantalum; 400 to1000 mL capacity, double-ended, with valves at each end,specially cleaned. Cylinders with
17、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 aseptum fitting on one end.NOTE 1A procedure for cleaning cylinders and valves, for use withliquid chlorine, is given in Test Method E 806, Appendix X
18、2.5.5.2 Needle and Ball Valve, nickel body, having packingresistant 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.) nut.5.5.4 Glove Bag or Dry Box, purged with dry nitrogen (lessthan 5 ppm water vapor).5.5.5 Fittings, for
19、 transferring chlorine from one cylinder toanother.5.5.6 0 to 10- L 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 Hygrom
20、eter, capable of measuring moisture as low as5 mg/kg (ppm) in glove bag or dry box.5.6 Silicone Rubber Septa.5.7 Mechanical Shaker.5.8 Drying Oven.6. Reagents6.1 Purity of WaterSee Specification D 1193.6.2 Chlorine, liquid with less than 5 mg/kg (ppm) water.6.3 Methylene Chloride (CH2Cl2).NOTE 2This
21、 reagent is used for cooling purposes only.6.4 Dry Ice (CO2).6.5 Dry Nitrogen, (5 mg/kg (ppm) water) to purge glovebag or dry box 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-m
22、ent, except the infrared spectrophotometer, when this mate-rial is analyzed in the laboratory.7.1.2 The analysis should 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 adequat
23、e eye protection (chemical gogglesare recommended) and an approved chlorine respirator.Splashes of liquid chlorine destroy 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 operatio
24、ns should bewarned of the possible release of chlorine.7.1.4 It is recommended that means be available for disposalof excess chlorine in an environmentally safe and acceptablemanner. If chlorine cannot be disposed of in a chlorineconsuming process, a chlorine absorption system should beprovided. Whe
25、n the analysis and sampling regimen requires aninitial purging of chlorine from a container, the purged chlorineshould be similarly handled. Purging to the atmosphere shouldbe avoided.7.1.5 In the event chlorine is inhaled, first aid should besummoned immediately.FIG. 2 Sample Cylinder AssemblyE 175
26、4 0848. 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” where the concentrationsof impurities in the chlorine will never change because thechlorine never moves. If sampling through secondary pip
27、ing,that piping should be purged well with nitrogen or dry airbefore being blocked in. Otherwise, temperature variations canresult in water vapor condensing inside the piping to contami-nate the chlorine sample when it is grabbed. Finally, samplingshould be done at a sample point representative of t
28、he chlorineneeding to be analyzed.8.1.1 Sampling from tank cars, barges, storage tanks, andlarge cylinders presents unique problems. Each facility, how-ever, must be capable of delivering a liquid sample (not gas).Acceptable samples can be obtained by sampling in accordancewith the Chlorine Institut
29、e Pamphlet No. 77, “Sampling LiquidChlorine”4.(See 49 CFR 173, including Parts 173.304,173.314, and 173.315.)8.2 It is recommended that samples be collected from thesefacilities in the sample cylinder assembly listed in 5.5. Properand safe sampling techniques must be followed. The cylindermust conta
30、in at least 75 % by volume of liquid chlorine (lessthan 25 % vapor space).NOTE 3Do not allow the cylinder to become liquid full. Tare thecylinder, 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 chlori
31、ne) and by 0.75 to obtain the weight of chlorine to fill thecylinder 75 % full. Example: The cylinder holds 1000 g of water (1000mL, assuming 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 cylind
32、ers should be thoroughly dried byplacing in an oven at 105C for at least6horpreferablyovernight; the dip tubes are not heated, place them 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 cylind
33、ers are cooled with plant air orN2having 5 mg/kg (ppm) moisture. The valves are removed,placed in a desiccator with a suitable drying agent, and cooledto room temperature.9. Preparation of Standards for Calibration9.1 Obtain four clean, evacuated sample cylinders. Onlycylinders that have been proper
34、ly pressure-tested should beused. Equip three with a ball valve and a needle valve, labelthese Cylinders No. 2 through No. 4 and record weight to 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
35、 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 valve. Check thehygrometer to make sure the atmosphere in the glove bag ordry box contains 5 mg/kg (ppm) moisture before performingany transfers of chlorine
36、.9.2 Load the four cylinders with liquid chlorine. The liquidchlorine should contain less than 5 mg/kg (ppm) water. Allcylinders must contain at least 75 % by volume liquid chlorine(less than 25 % vapor space). All cylinders should be weighedto the nearest gram and recorded to determine the weight o
37、fchlorine in each cylinder (Note 3). Place the filled cylindersinto the glove bag or dry box inside the hood. Place all fittings,tools and equipment, including the purged infrared cell, in theglove bag or dry box. Wait until the hygrometer in the glovebag or dry box is reading 5 mg/kg (ppm) moisture
38、 beforeproceeding.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 the cylinder and the specialinfrared cell to the filling apparatus (see Fig. 2) in such a waythat the liquid chlorine will flow into th
39、e 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 Valve F and then Valve A. Flush the fillingapparatus by partially opening Valve B for a few seconds andthen closing it. Leave Valve A
40、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 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 e
41、mpty 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 thefilling apparatus after blowing ValveAwith N2. Make sure thatthe cylinder is connected to the apparatus in such a way that theliquid
42、 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, refer 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 compl
43、ete 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 dump asmall amount of chlorine from the inverted cell, then quicklyclose. The cell window should have about15 vapor space wheninverted.
44、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 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 chlor
45、ine. Make sure that no morethan14 to15 of the cell window is vapor space when the cellis inverted. Remove Cylinder No. 1 and No. 2 and record theirweights.9.11 Place the infrared cell in the spectrometer and scan intransmission mode from 400 to 4400 wavenumbers at4-wavenumber resolution. Ratio this
46、spectrum to a spectrumtaken of the infrared cell filled with nitrogen. Then convert the4Available from The Chlorine Institute, Inc., 2001 L St. NW, Washington, DC20036.E 1754 085ratioed transmission spectrum to absorbance and measure thenet absorbance of the band at 1596 wavenumber relative to arefe
47、rence 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. Infrared absorbance spectra of the three cyli
48、ndersof 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 for Cylinder No. 3 is 20 mAU.9.14 Add approxi
49、mately 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 lowerCylinder No. 2 into the methylene chloride/dry ice mixture forcooling. The mixture should cover about23 of 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(ppm). Use the weight of the cylinder after filling the cell todetermi
