ASTM E1754-17a Standard Test Method for Determination of Low Levels of Water in Liquid Chlorine By Infrared Spectrophotometry.pdf

1、Designation: E1754 17aStandard Test Method forDetermination of Low Levels of Water in Liquid Chlorine ByInfrared Spectrophotometry1This standard is issued under the fixed designation E1754; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev

2、ision, 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 covers the determination of the contentof water in liquid chlorine in the concent

3、ration range of 0.5 to15 mg/kg (ppm).1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.3 Review the current Safety Data Sheets (SDS) for de-tailed information concerning toxicity, first aid procedures, andsafety precautions.1.4

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 determine the applica-bility of regulatory limitations prior to use. See Section 7 for

5、specific hazards statements.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organ

6、ization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE806 Test Method for Carbon Tetrachloride and Chloroformi

7、n Liquid Chlorine by Direct Injection (Gas Chromato-graphic Procedure)2.2 Federal Standards:349 CFR 173 Code of Federal Regulations Title 49 Transpor-tation: ShippersGeneral Requirements for Shipments andPackaging, including Sections:173.304 Charging of Cylinders with Liquefied CompressedGas173.314

8、Requirements for Compressed Gases in Tank Cars173.315 Compressed 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

9、wavenumbers of theinfrared transmission spectrum of liquid chlorine. 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

10、1663 wavenumbers, isdetermined. The amount of water corresponding 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 detr

11、imental to the use ofchlorine in some applications. The amount of water in thechlorine must be known to prevent problems during its use.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic, Industrial, Specialty and Related Chemicals and is the direct responsi-bility of Subco

12、mmittee D16.16 on Industrial and Specialty Product Standards.Current edition approved July 1, 2017. Published July 2017. Originally approvedin 1995. Last previous edition approved in 2017 as E1754 17. DOI: 10.1520/E1754-17a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcont

13、act ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office, Superintendent ofDocuments, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:/www

14、.access.gpo.gov.*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 StatesThis international standard was developed in accordance with internationally recognized principles on stan

15、dardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15. Apparatus5.1 Infrared Spectrometer, capable of measurements in the1600 wavenumber reg

16、ion. 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 cell size norpathlength are critical to the analysis, but sensitivity and limitof detection are dependent on p

17、athlength. The concentrationrange reported in the scope is achievable with a 60-mmpathlength cell constructed with:FIG. 1(a) Pipe AdapterFIG. 1(b) Air Cap DetailNOTE 1Drawing not to scale.FIG. 1 Infrared CellE1754 17a2FIG. 1(c) Body DetailFIG. 1(d) Gasket DetailFIG. 1(e) Insert DetailFIG. 1(f) Flang

18、e DetailE1754 17a35.2.1 Hastelloy C and 316 Stainless Steel Stock, suitable formachining.5.2.2 Silver Chloride Windows, 0.5 by 2.5 cm.5.2.3 Perfluoroelastomer Sheet, 0.030 in. thickness.5.3 Ball Valves, Monel414 in. valve with pipe and14 in. tubeends.5.4 Needle Valves, nickel or Monel46.35 mm (14 in

19、.) 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,4or 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 on

20、e 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 E806, Appendix X2.5.5.2 Needle and Ball Valve, nickel body, havi

21、ng packingresistant to liquid chlorine. If nickel valves are not available,Monel4valves 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 transferring chlorine from one cylinder toanoth

22、er.5.5.6 0to10-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 Hygrometer, capable of measuring moisture as low as5 mg/k

23、g (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 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 I

24、ce (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 testequipment, except the infrared spectrophotometer, when thism

25、aterial 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 adequate eye protection (chemical gogglesare recommended) and a

26、n 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 operations should bewarned of the possible release of chlorine.7

27、.1.4 It is recommended that means be available for disposalof excess chlorine in an environmentally safe and acceptable4Monel is a registered trademark of Special Metals Corporation.FIG. 2 Sample Cylinder AssemblyE1754 17a4manner. If chlorine cannot be disposed of in a chlorineconsuming process, a c

28、hlorine absorption system should beprovided. When 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

29、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” where the concentrationsof impurities in the chlorine will never change because thechlorine never moves. If sampling through second

30、ary piping,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 representati

31、ve of the chlorineneeding to be analyzed.8.1.1 Sampling from tank cars, barges, storage tanks, andlarge cylinders presents unique problems. Each facility,however, must be capable of delivering a liquid sample (notgas). See Chlorine Institute Pamphlet No. 1, “ChlorineBasics.”5(See 49 CFR 173, includi

32、ng 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 contain at least 75 % by volume of liquid chlorine (lessthan 25 % vapor spa

33、ce).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 chlorine) and by 0.75 to obtain the weight of chlorine to fill thecylinder 7

34、5 % 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 cylinders should be thoroughly dried byplacing in an oven at 105C for at lea

35、st6horpreferablyovernight; 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 cylinders are cooled with plant air orN2having 5 mg/kg (ppm) moisture. The v

36、alves 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 properly pressure-tested should beused. Equip three with a ball valve and a

37、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 be used to purge the infrared cellbefore standards are loaded. Use ca

38、ps 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.9.2 Load the four cylinders with liquid chlorine. The liquidchlorine

39、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 ofchlorine in each cylinder (Note 3). Place the filled cylindersinto th

40、e 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 beforeproceeding.9.3 Remove the cap on Valve A of Cylinder No. 1 and

41、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 the cell and that thevalves on all parts of the apparatus are closed pri

42、or 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 open.9.4.1 Open Valves E and C. Flush the cell by partiallyopening Val

43、ve 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 empty the cell once more, as above.9.6.1 Close Valve A and open Valve B

44、, 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 chlorine will flow into the cell and that the valves on allparts of t

45、he 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 complete filling of the cell window andthen close Valve A.9.9 Vent the resi

46、dual 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. Then close Valves B and E.9.10 Allow the cell to come to ambient tempe

47、rature. Beforeremoving the cell from the filling apparatus, check again for5Available from The Chlorine Institute, Inc., 1300 Wilson Blvd., Suite 525,Arlington, VA 22209.E1754 17a5adequate vapor space in the inverted cell window. If no vaporspace is seen, open Valve B and quickly open and close Valv

48、eC a little to dump some more chlorine. 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

49、-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 the band at 1596 wavenumber relative to areference at 1663 wavenumbers.9.12 Repeat the operations above (9.4 9.11, omit 9.6.1)with chlorine 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