1、BRITISH STANDARD BS 3947:1976 Specification for Liquid chlorine UDC 661.416:661.9404:546.13121BS3947:1976 This BritishStandard, having been prepared under the directionof the Chemicals Standards Committee, was published underthe authority ofthe Executive Board on 30September1976 BSI 12-1999 First pu
2、blished November1965 First revision September1976 The following BSI references relate to the work on this standard: Committee reference CIC/19/3 Draft for comment 74/53821 DC ISBN 0 580 09472 4 Cooperating organizations The Chemicals Standards Committee, under whose supervision this BritishStandard
3、was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Fatty Acid Distillers Chemical Industries Association* Department of Health and Social Security Department of Industry Laboratory of the Government Chemist
4、Fertilizer Manufacturers Association Institute of Vitreous Enamellers Ministry of Agriculture, Fisheries and Food National Sulphuric Acid Association Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association Society for Analytical Chemistry The organization marked with an
5、asterisk in the above list, together with the following, was directly represented on the committee entrusted with the preparation of this BritishStandard: British Fire Services Association Electricity Supply Industry in England and Wales Ministry of Defence Royal Institute of Chemistry National Wate
6、r Council Amendments issued since publication Amd. No. Date of issue CommentsBS3947:1976 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover Foreword iii 1 Scope 1 2 References 1 3 Description 1 4 Sampling 1 5 Chlorine content 1 6 Water content 1 7 Residue on evaporation 1 8 Pac
7、kaging and marking 1 Appendix A Methods of sampling and vaporizing liquid chlorine and of disposing of chlorine gas 2 Appendix B Method for the determination of chlorine content 4 Appendix C Method for the determination of water content: gravimetric method 5 Appendix D Method for the determination o
8、f water content using an electrolytic analyser 8 Appendix E Alternative method of calibration of the electrolytic cell for the determination of water content 11 Appendix F Method for the determination of residue on evaporation 13 Appendix G Method for the determination of nitrogen trichloride conten
9、t 14 Figure 1 Diagram of sample point from a pipe containing a flowing stream of liquid chlorine 17 Figure 2 Sampling into pressurized sample containers 18 Figure 3 Liquid chlorine sample container 19 Figure 4 Head of liquid chlorine sample container 20 Figure 5 Checking of chlorine sample container
10、 before taking the sample 21 Figure 6 Sampling into non-pressurized sample containers 21 Figure 7 Non-pressurized sample containers 22 Figure 8 Vaporization of a sample from a pressurized source 23 Figure 9 Chlorine absorption apparatus 24 Figure 10 Volumetric flask for determining chlorine content
11、25 Figure 11 Calibration graph giving the water content of the magnesium perchlorate as a function of the increase in temperature resulting from the heat of solution under the conditions ofC.10 26 Figure 12 Determination of water content: gravimetric method 27 Figure 13 Diagram of electrolytic analy
12、ser 28 Figure 14 Equilibrium diagram showing moisture content of chlorine after bubbling in sulphuric acid as a function of acid concentration and temperature 29 Figure 15 Diagram of electrolytic analyser and the calibration device 30 Figure 16 Device for drawing off solvent 31 Figure 17 Liquid chlo
13、rine. Variation of density with temperature 32 Figure 18 Example of recorder chart 33 Figure 19 Bubbler for determination of nitrogen trichloride 33BS3947:1976 ii BSI 12-1999 Page Figure 20 Apparatus for the determination of nitrogen trichloride content 34 Publications referred to Inside back coverB
14、S3947:1976 BSI 12-1999 iii Foreword This BritishStandard, prepared under the authority of the Chemicals Standards Committee, comprises a specification for liquid chlorine suitable for a range of industrial uses. It is a revision of the first edition which was published in1965; the latter is now with
15、drawn. Chlorine is a powerful irritant to the skin, mucous membrane and respiratory system. Users should consult the following publications. a) “Precautions in handling, storage and use of liquid chlorine”; Safety and Health, new series No.37, published byH.M.S.O. b) “Methods for the detection of to
16、xic substances in air, booklet No.10, Chlorine” published by H.M. Factory Inspectorate. This provides data on the physiological response to various concentrations of chlorine gas. c) “Codes of practice for chemicals with major hazardsChlorine”, published by the British Chemical Industries Safety Cou
17、ncil of the Chemical Industries Association Ltd. Because of the hazardous nature of liquid chlorine, intending users should consult the chlorine manufacturers on the design of chlorine handling equipment and on suitable operating procedures. The latter should include employee training, protective eq
18、uipment, emergency measures, provision of suitable first aid equipment and procedures for vaporization and sampling. Users are warned that it is dangerous to vaporize large quantities of liquid chlorine (for example from large storage tanks) so that the less volatile nitrogen trichloride, which on d
19、ecomposition can give rise to a violent explosion, concentrates in the residues. The manufacturer should be consulted on the procedure for vaporization. This revision incorporates (seeAppendix C,Appendix D andAppendix E) two International Standards in the preparation of which the UnitedKingdom has b
20、een an active participant. These are both related to liquid chlorine for industrial use and are ISO2121, ISO2202 and ISO2202, Addendum1. They form alternatives replacing the single method given in AppendixB of BS3947:1965. Appendix A gives methods of sampling and vaporizing liquid chlorine in which
21、the method for sampling into pressurized sample containers(A.2) is technically similar to the equivalent method described in ISO/R1552. An improved method for determination of nitrogen trichloride content is given in Appendix G. Certification. Attention is drawn to the certification facilities descr
22、ibed on theinside back cover. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of
23、pages This document comprises a front cover, an inside front cover, pagesi to iv, pages1to34, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.i
24、v blankBS3947:1976 BSI 12-1999 1 1 Scope This BritishStandard specifies requirements for liquid chlorine for general industrial use. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Description Liquid chlorine is a clear yellow liquid, w
25、hich on vaporizing gives a greenish yellow gas. It is gaseous at atmospheric temperatures and pressures. The chlorine supplied in the customary pressure containers is present in both liquid and gaseous phases. 4 Sampling The methods of sampling given in Appendix A shall be used, as appropriate, for
26、the purposes of this specification. 5 Chlorine content The chlorine content of the vaporized liquid shall be not less than99.5%(v/v) when determined by the method described in Appendix B. 6 Water content The water content of the vaporized liquid shall not exceed100mg/kg when determined by either of
27、the methods described in Appendix C andAppendix D (seealso Appendix E). 7 Residue on evaporation The residue on evaporation of the liquid shall not exceed200mg/kg on evaporation at20 C, when determined by the method described in Appendix F. 8 Packaging and marking Liquid chlorine shall be supplied o
28、nly in steel containers which satisfy the recommendations of the Home Office for design, construction 1) , marking, maintenance and contents limitation. NOTEIn the cases of rail and sea conveyance, the containers have also to be approved in these respects by British Rail and the Department of Trade
29、(Marine Division) respectively under their regulations for the carriage of dangerous goods. 1) Attention is drawn to BS401 and BS349. A claim that the container complies with the requirements of BS401 does not imply that its contents meet the requirements of BS3947.BS3947:1976 2 BSI 12-1999 Appendix
30、 A Methods of sampling and vaporizing liquid chlorine and of disposing of chlorine gas NOTEExcept for the method described inA.2, there is no equivalent ISO method. A.1 General This appendix gives procedures, for use in the methods of test described in the other appendices, by means of which liquid
31、chlorine may be sampled from a flowing stream, or from a pressure vessel, vaporized and subsequently absorbed. It comprises procedures for: a) sampling into pressurized sample containers(A.2); b) sampling into non-pressurized sample containers(A.3); c) vaporization of sample from pressurized sources
32、(A.4); d) vaporization of sample from non-pressurized containers(A.5); e) disposal of chlorine gas(A.6). Samples should be taken from the bulk of the liquid to be sampled. In the case of chlorine supplied in containers, this can be done by using a dip tube: in the case of samples from a flowing stre
33、am, the arrangement shown in Figure 1 should be used. Where possible, determinations should be carried out by vaporizing liquid chlorine directly from the source. If samples have to be taken, stainless steel or glass sample containers should be used. A.2 Sampling into pressurized sample containers N
34、OTEThis method is technically similar to the equivalent method described inISO/R1552. A.2.1 Apparatus. The installation, shown diagrammatically in Figure 2, comprises the following. A.2.1.1 Sample container, constructed of stainless steel, complying with the requirements of BS401 and having a usable
35、 capacity of from1litre to10litres (seeexample in Figure 3 and Figure 4), the shorter tube having a length so calculated to give12% to15% of ullage. For the purposes of sampling, the usable capacity V, i.e.the volume from the bottom of the sample container to the lower end of the shorter tube, shall
36、 be determined initially by weighing before and after filling the sample container with water at20 C. The value of1.25V shall be inscribed on the sample container (seeA.2.2). NOTEGlass-lined sample containers may also be used, provided their pressure rating is adequate. A.2.1.2 Connection pipes and
37、needle valves made of chlorine-resistant materials, e.g.stainless steel. The equipment should be kept free from moisture at all times, as stainless steel is attacked by wet chlorine. A.2.2 Procedure. Weigh the clean and dry sample container(A.2.1.1). Check that there is no blockage in the dip tube b
38、y connecting the vessel to a vacuum pump, as indicated in Figure 5, and opening both valves carefully and progressively. The rapid passage of air, observed in the sulphuric acid bubbler, indicates the absence of any blockage. Check that the valves are functioning correctly by closing them alternatel
39、y. The passage of air should then cease. Weigh the sample container and connect it to the installation illustrated in Figure 2 with all the valves closed. Open valve V 1to allow the chlorine to flow to valve V 2 . Close valve V 1and open valve V 2and check the connections for gas tightness with a li
40、ttle soapy water. Open valves V 1and V 3to allow liquid chlorine to flow through the system as indicated by the arrows in Figure 2. Allow the liquid to flow for a suitable time to obtain a representative sample. Close valves V 1 , V 2and V 3in succession and immediately open valve V 4to allow the ch
41、lorine contained in the piping to evaporate. If necessary heat the pipes with steam. Then close valve V 4and disconnect the sample container. Check for correct filling of the sample container in the following manner. Wipe away any condensation water on the outer wall and weigh the filled sample cont
42、ainer. The mass of the liquid chlorine sample (M 2 M 1 ) shall not exceed1.25V where M 1 is the mass of the empty sample container (kg); M 2 is the mass of the filled sample container (kg); V is the volume of the sample container from the bottom of the sample container to the lower end of the shorte
43、r tube (litres).BS3947:1976 BSI 12-1999 3 If the mass, in kilograms, exceeds the value of1.25V, reconnect the sample container to the sampling installation and discharge the excess of liquid chlorine by opening valveV 3 . A.3 Sampling into non-pressurized sample containers A.3.1 Apparatus A.3.1.1 Sa
44、mpling system, a typical example of which is shown in Figure 6, comprising: a) two sampling flasks; b) two vacuum-jacketed cooling baths containing a mixture of solid carbon dioxide with a suitable solvent such as trichloroethylene. WARNING. Because of the toxicity of trichloroethylene, it is recomm
45、ended that it should be handled with care and in a well-ventilated fume cupboard. A.3.1.2 Chlorine absorption apparatus, as shown in Figure 9 (seeA.6). A.3.1.3 Thermometer, spirit in glass, complying with the requirements of BS1704, type B, capable of measuring temperatures down to80 C. A.3.2 Proced
46、ure. Assemble the appropriate sampling flasksA.3.1.1 a), connect to the appropriate chlorine source as shown in Figure 6 and immerse in the cooling mixture. Collect a suitable quantity of liquid in the first flask, maintaining the temperature of the cooling mixture at50 C or lower. Close the contain
47、er valve securely while the flasks are still connected and immersed in the cooling bath. Disconnect the flasks from the chlorine source and insert their stoppers. NOTEAlcohols should not be used for cooling as they can react with chlorine to form explosive organic hypochlorites. A.4 Vaporization of
48、sample from pressurized sources A.4.1 Apparatus, shown in Figure 8, comprising the following. A.4.1.1 Filter (F), consisting of a threaded stainless steel tube approximately6mm internal diameter and150mm long, filled with glass wool. A.4.1.2 Stainless steel needle valve (V 5 ) A.4.1.3 Three-way stop
49、cock (R 1 ), used as a safety by-pass valve or as a means of introducing nitrogen or air purges. NOTEStopcocks, etc.,should be lubricated with chlorine-resistant grease. Greases based on fluorinated or chlorofluorinated products are suitable. A.4.1.4 Stainless steel coil, 250mm to500mm in length,6mm to8mm internal diameter, immersed in a bath of water which is heated to80 C by means of an electric heater (H). A.4.1.5 Electric heater (H) A.4.1.6 Glass safety lute (P) filled with carbon tetrachloride. Varying the height h wil
