BS 4366-1993 Specification for industrial nitrogen《工业氮规范》.pdf

1、BRITISH STANDARD BS4366:1993 Specification for Industrial nitrogen UDC661.938BS4366:1993 This British Standard, having been prepared under the direction of the Chemicals Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 February1993 BSI0

2、4-1999 First published November1968 Withdrawn1988 Second edition February1993 The following BSI references relate to the work on this standard: Committee reference CIC/19 Draft for comment92/81607DC ISBN 0 580 21537 7 Committees responsible for this British Standard The preparation of this British S

3、tandard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/19, upon which the following bodies were represented: Brewers Society British Compressed Gases Association British Soft Drinks Association Ltd. Ministry of Defence Amendments issued since publication

4、 Amd. No. Date CommentsBS4366:1993 BSI 04-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Description 1 4 Sampling 1 5 Oxygen content 1 6 Carbon monoxide and carbon dioxide content 1 7 Total hydrocarbons content 1 8 Water content 1 9 Nitrogen con

5、tent 1 10 Containers 1 11 Labelling 1 Annex A (informative) Safety considerations for the handling of nitrogen 2 Annex B (normative) Method for the determination of oxygen content 2 Annex C (normative) Method for the determination of carbon monoxide and carbon dioxide content 4 Annex D (normative) M

6、ethod for the determination of total hydrocarbons content 4 Annex E (normative) Method for the determination of water content 4 Figure B.1 Configuration of unit for electrochemical determination of oxygen using aqueous electrolyte 3 Figure B.2 Configuration of unit for electrochemical determination

7、of oxygen using gel electrolyte 3 Figure D.1 Flame ionization detector (schematic) 4 List of references Inside back coverBS4366:1993 ii BSI 04-1999 Foreword This British Standard has been prepared under the direction of the Chemicals Standards Policy Committee. BS4366:1968 was withdrawn in1988 as ob

8、solete. At about the same time an EC draft Directive on Food Additives (including gases) was issued, requiring standards of purity of additives to be established in the implementing legislation. This, together with representation from numerous concerns, in particular the welding industry, indicated

9、a need for a revised British Standard to be prepared. This standard represents a complete revision of BS4366:1968, in order to provide a practical standard for both producers and users of industrial nitrogen. Current analytical methods are referred to, in order to present a readily reproducible syst

10、em of checking compliance with the requirements of this standard. Annex A is included as a reminder that safety conditions are paramount. Full details of sampling for analytical purposes are included in BS5309-2, which includes references to compressed and liquefied gases. This standard is one of a

11、pair prepared in parallel, the other being BS4364:1993 Specification for industrial oxygen. Reference to this standard may be made: by a purchaser of products; by a supplier when specifying products offered; by consumer interests and legislative bodies. The role of a purchaser in monitoring a suppli

12、ers compliance with the requirements of this standard may be fulfilled by a third party, such as an accreditation or certification body. Product certification. Users of this British Standard are advised to consider the desirability of third party certification of product conformity with this British

13、 Standard based on testing and continuing product surveillance which may be coupled with assessment of a suppliers quality systems against the appropriate Part of BS5750. Enquiries as to the availability of third party certification schemes are forwarded by BSI to the Association of Certification Bo

14、dies. If a third party certification scheme does not already exist, users should consider approaching an appropriate body from the list of Association members. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for th

15、eir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see c

16、opyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4366:1993 BSI 04-1999 1 1 Scope This British Standard specifies requirements for nitrogen that is to be used in industrial applications. It also describes the analytical

17、 principles and methods to be used to demonstrate compliance with the specification. Requirements for containers and their labelling are also specified. This standard does not apply to nitrogen for medical, breathing, electronics, or other applications where more demanding impurity limits may apply.

18、 NOTEThe nitrogen is referred to hereafter as “the product”. 2 References 2.1 Normative references This standard incorporates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are li

19、sted on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this standard only when incorporated in it by updating or revision. 2.2 Informative references This standard refers to other publications that provide information or guidance. Editions of the

20、se publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Description The product shall consist essentially of nitrogen, N 2 , in the form of a compressed gas or a liquid. NOTEThe gaseous product is colou

21、rless, odourless and tasteless, and slightly less dense than air at equal temperatures. The liquid product is odourless and colourless, and boils at196 C at101.3kPa pressure. One volume of liquid product gives approximately678 volumes of gas at15 C and101.3kPa. 4 Sampling For the purpose of sampling

22、 the product for analysis, the provisions of BS5309-2:1976 shall apply. 5 Oxygen content When determined by the method described in Annex B, the product shall contain a volume fraction of oxygen (O 2 ) of not more than15/10 6in the gaseous form and not more than5/10 6in the liquid form. 6 Carbon mon

23、oxide and carbon dioxide content When determined by the method described in Annex C, the product shall contain a volume fraction of carbon monoxide (CO) of not more than5/10 6and shall contain a volume fraction of carbon dioxide (CO 2 ) of not more than1/10 6 . 7 Total hydrocarbons content When dete

24、rmined by the method described in Annex D, the product shall contain a volume fraction of hydrocarbons expressed as methane of not more than1/10 6 . 8 Water content When determined by the method described in Annex E on a fully charged container, the product shall contain a volume fraction of water o

25、f not more than10/10 6in the gaseous form and not more than2/10 6in the liquid form. NOTE 1As product is removed from a fully charged container the contribution of water from the container wall may increase. NOTE 2Cryogenic liquids do not contain water as such, but may contain ice crystals. The deli

26、very system from a source of liquid product can also contribute water from its surfaces to the product stream. 9 Nitrogen content After determination of the total content of specified impurities the balance shall consist of nitrogen, plus any traces of noble gases present. 10 Containers The gaseous

27、product shall be supplied in containers painted in accordance with BS349:1973. NOTE 1For gaseous product attention is drawn to the Pressure Systems and Transportable Gas Containers Regulations, SI1989 No.21691 and amendments thereof which are currently in force. NOTE 2The liquid product is typically

28、 supplied in specialized vacuum insulated containers for which there is no British Standard. 11 Labelling The container in which the product is supplied shall be clearly labelled with the following: a) the name, address and registered trade mark of the manufacturer or supplier; b) the caption: “NITR

29、OGEN.” NOTEAttention is drawn to the Classification, Packaging and Labelling of Dangerous Substances Regulations, SI1984 No.12442 and amendments thereof which are currently in force.BS4366:1993 2 BSI 04-1999 Annex A (informative) Safety considerations for the handling of nitrogen The product is non-

30、toxic, but constitutes an asphyxiation hazard through the displacement of oxygen in air. The liquid product and the cold gaseous product can cause severe burns or frostbite when in contact with the skin or respiratory tract. The product should not be used in confined spaces without ventilation. Pers

31、onnel should not enter areas enriched with nitrogen. Annex B (normative) Method for the determination of oxygen content B.1 Principle The method uses the principle of electrochemical reduction of any oxygen present in a stream in a detection cell containing either a gel or aqueous solution of electr

32、olyte where the following reactions take place: O 2 +2H 2 O+4eF4OH at the cathode and 2Pb+4OH F 2Pb(OH) 2 +4e at the anode, with the complete reaction represented by: 2Pb+O 2 +2H 2 O F 2Pb(OH) 2 In some instances, electrodes other than lead may be used. B.2 Apparatus A variety of analytical equipmen

33、t suppliers provide simple, ready to run portable units for this purpose, which may be powered either by battery or mains electricity. Figure B.1 illustrates the configuration of a typical unit designed for this purpose, using aqueous electrolyte. NOTE 1Such units require flow to produce any pertine

34、nt signal output and to assist in calibration an adsorbent oxygen scrubber is included in the analyser circuit. Figure B.2 illustrates the configuration of a typical unit designed for this purpose using gel as an electrolyte. NOTE 2In this instance any flow variation is not crucial to the measuremen

35、t. B.3 Calibration Calibration of these units shall be carried out using a calibration mixture produced in accordance with BS4559 and the manufacturers instructions, and conveyed to the analyser in accordance with BS5309-2:1976. B.4 Procedure After calibrating the instrument, introduce the sample of

36、 the product in accordance with the manufacturers instructions and BS5309-2:1976. Record the oxygen content that is displayed by the instrument.BS4366:1993 BSI 04-1999 3 Figure B.1 Configuration of unit for electrochemical determination of oxygen usingaqueouselectrolyte Figure B.2 Configuration of u

37、nit for electrochemical determination of oxygen usinggelelectrolyteBS4366:1993 4 BSI 04-1999 Annex C (normative) Method for the determination of carbon monoxide and carbon dioxide content C.1 Principle The method uses the principle of infra-red absorption by different molecules at specific wavelengt

38、hs in the infra-red spectrum. C.2 Apparatus C.2.1 Scanning infra-red spectrometer, complying with BS4314-1:1968, and fitted with a gas cell of10m minimum optical path length. C.3 Calibration Calibration of these units shall be carried out using a calibration mixture produced according to BS4559 and

39、the manufacturers instructions, and conveyed to the analyser in accordance with BS5309-2:1976. C.4 Procedure After calibrating the instrument, introduce the sample of the product in accordance with the manufacturers instructions and BS5309-2:1976. Calculate the carbon monoxide and carbon dioxide con

40、tents in accordance with BS4314-1:1968. Annex D (normative) Method for the determination of total hydrocarbons content D.1 Principle The method uses the principle of ionizing the hydrocarbon molecules that are present in a particular sample in a flame, and monitoring the change in potential across t

41、wo electrodes in close proximity to the flame, as illustrated in Figure D.1.The change in potential is proportional to the quantity of hydrocarbons present. D.2 Apparatus D.2.1 Gas chromatograph, fitted with a flame ionization detector, a gas sampling valve, and a suitable valve to enable hydrocarbo

42、ns to be “backflushed” to the detector. Nitrogen carrier gas shall be used. NOTEWhile the provisions of BS5443 will assist with the specification of such a system, many other variables, such as column type, length, carrier flow, detector temperature and oven temperature, may be left open, and still

43、provide a suitable system for determination of this impurity. D.3 Calibration Calibration of these units shall be carried out using a calibration mixture produced in accordance with BS4559 and the manufacturers instructions, and conveyed to the analyser in accordance with BS5309-2:1976.The mixture s

44、hall, however, contain only methane in a balance of nitrogen, and the result of the calibration shall be expressed as “Total hydrocarbons calibrated as methane”. D.4 Procedure After calibrating the instrument, introduce the sample of the product in accordance with the manufacturers instructions and

45、BS5309-2:1976. Record the output signal on a computing integrator, and calculate the concentration of hydrocarbons in accordance with the computing integrator manufacturers instructions. Annex E (normative) Method for the determination of water content E.1 Principle The gas is passed through a direc

46、t reading hygrometer. Figure D.1 Flame ionization detector (schematic)BS4366:1993 BSI 04-1999 5 E.2 Apparatus E.2.1 A direct reading hygrometer, of one of the following types: a) cooled mirror dew point; b) electrolytic; c) capacitance; d) piezoelectric. E.3 Calibration Ensure that the instrument ha

47、s a current certificate of calibration demonstrating traceability to the UK national standard held at the National Physical Laboratory. E.4 Procedure Operate the direct reading hygrometer in accordance with the manufacturers instructions. Keep all sample lines as short as practicable and, together w

48、ith all ancillary equipment, ensure that they have only polytetrafluoroethylene or stainless steel wetted parts. Introduce the sample of the product in accordance with the manufacturers instructions and BS5309-2:1976. Record the water content that is displayed by the instrument.6 blankBS4366:1993 BS

49、I 04-1999 List of references (see clause2) Normative references BSI standards publications BRITISH STANDARDS INSTITUTION, London BS349:1973, Specification for identification of the contents of industrial gas containers. BS4314, Specification for apparatus for physical methods of gas analysis. BS4314-1:1968, Infra-red gas analysers for industrial use. BS4559, Methods for preparation of calibration gas mixtures. BS4559-1, Weighing methods. BS4559-1.1:1983, Mixtures containing components fully vaporizable under ambient conditions. BS4559-3: