1、BRITISH STANDARD BS EN ISO 10101-2:1998 BS 3156-11.3.2: 1994 Implementing Amendment No. 1 to BS 3156-11.3.2:1994 ISO10101-2:1993 (renumbers the BS as BSENISO 10101-2:1998) not published separately Natural gas Determination of water by the Karl Fischer method Part 2: Titration procedure The European
2、Standard EN ISO 10101-2:1998 has the status of a British Standard ICS 75.060BSENISO10101-2:1998 This British Standard, having been prepared under the directionof the Petroleum Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15 March 1994 BSI
3、 05-1999 The following BSI references relate to the work on this standard: Committee reference PTC/15 Draft for comment 92/52711 DC ISBN 0 580 22956 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Petroleum Standards Policy Committee (
4、PTC/-) to Technical Committee PTC/15 upon which the following bodies were represented: British Compressed Gases Association British Gas plc Department of Trade and Industry (Gas and Oil Measurement Branch) Department of Trade and Industry (National Engineering Laboratory) Institute of Petroleum Amen
5、dments issued since publication Amd. No. Date Comments 10052 July 1998 Implementation of EN ISO 10101-2:1998BSENISO10101-2:1998 BSI 05-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Reagents 3 5 Appara
6、tus 4 6 Standardization of the Karl Fischer reagent 4 7 Sampling 5 8 Procedure 5 9 Expression of results 5 10 Test report 6 Annex A (normative) Karl Fischer apparatus 7 Annex ZA (normative) Normative references to international publications with their relevant European publications 10 Figure A.1 Det
7、ail of titration cell 8 Figure A.2 Titration apparatus Typical assembly 9 Figure A.3 Schematic circuit diagram 9 List of references Inside back coverBSENISO10101-2:1998 ii BSI 05-1999 National foreword This British Standard has been prepared under the direction of the Petroleum Standards Policy Comm
8、ittee and is the English language version of ENISO10101-2:1998 Natural gas Determination of water by the Karl Fischer method Part2:Titration procedure published by the European Committee for Standardization (CEN). It is identical with ISO10101-2:1993 published by the International Organization for S
9、tandardization (ISO). International Standard ISO10101-2 was prepared by Technical Committee ISO/TC193, Natural gas, Subcommittee SC1, Analysis of natural gas, in which the United Kingdom participated. ISO 10101 consists of the following Parts, under the general title Natural gas Determination of wat
10、er by the Karl Fischer method. Part 1: Introduction; Part 2: Titration procedure; Part 3: Coulometric procedure. Annex A forms an integral part of this Subsection of BS3156. Cross-references The Technical Committee has reviewed the provisions of ISO7504:1984, to which normative reference is made in
11、the text, and has decided that they are acceptable for use in conjunction with this standard. 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 n
12、ot of itself confer immunity from legal obligations. International standard Corresponding British Standard ISO 383:1976 BS 572:1985 Specification for interchangeable conical ground glass joints (Technically equivalent) BS 3156 Analysis of fuel gases Part 11 Methods for non-manufactured gases Section
13、 11.3 Determination of water in natural gas by theKarl Fischer method ISO 10101-1:1993 Subsection 11.3.1:1994 Introduction (Identical) ISO 10101-3:1993 Subsection 11.3.3:1994 Coulometric method (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii,
14、 theENISO title page, pages 2 to 10, 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 theinside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 10
15、101-2 March 1998 ICS 75.060 Descriptors: See ISO document English version Natural gas Determination of water by the Karl Fischer method Part2:Titration procedure (ISO 10101-2:1993) Gaz naturel Dosage de leau par la mthode de Karl Fischer Partie2:Mthode titrimtrique (ISO 10101-2:1993) Erdgas Bestimmu
16、ng des Wassergehaltes nach Karl Fischer Teil2:Titrimetrisches Verfahren (ISO 10101-2:1993) This European Standard was approved by CEN on 22 February 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the st
17、atus of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A
18、 version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, CzechRepublic, Denmark, Finland,
19、France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussel
20、s 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref. No. EN ISO 10101-2:1998 EENISO10101-2:1998 BSI 05-1999 2 Foreword The text of the International Standard from Technical Committee ISO/TC 193, Natural gas, of the International Organiza
21、tion for Standardization (ISO) has been taken over as a European Standard by CEN/CS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September1998, and conflicting national standards shall be with
22、drawn at the latest by September1998. According to CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal,
23、Spain, Sweden, Switzerland and theUnitedKingdom. Endorsement notice The text of the International Standard ISO 10101-2:1993 has been approved by CEN as a European Standard without any modification. NOTENormative references to International Standards are listed in Annex ZA (normative).ISO10101-2:1993
24、(E) BSI 05-1999 3 WARNING Local safety regulations must be taken into account, when the equipment is located in hazardous areas. Due to the toxicity and odour of pyridine, the user should ensure that there is adequate ventilation. 1 Scope This part of ISO10101 specifies a titrimetric procedure for t
25、he determination of water content in natural gas. Volumes are expressed in cubic metres at a temperature of273,15K (0C) and a pressure of101,325kPa (1atm). It applies to water concentrations between5mg/m 3and5000mg/m 3 . 2 Normative references The following standards contain provisions which, throug
26、h reference in this text, constitute provisions of this part of ISO10101. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO10101are encouraged to investigate the possibility of applying the most r
27、ecent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 383:1976, Laboratory glassware Interchangeable conical ground joints. ISO 7504:1984, Gas analysis Vocabulary. ISO 10101-1:1993, Natural gas Determination of wate
28、r by the Karl Fischer method Part1:Introduction. ISO 10101-3:1993, Natural gas Determination of water by the Karl Fischer method Part3:Coulometric procedure. 3 Principle A measured volume of gas is passed through a cell containing a relatively small volume of absorbent solution. Water in the gas is
29、extracted by the absorbent solution and, subsequently titrated with Karl Fischer reagent. The design of the cell and the absorbent solution are chosen so as to ensure efficient collection of the water at the high flowrates necessary. The principle and chemical reactions of the Karl Fischer method ar
30、e given in ISO10101-1:1993, clauses3 and4; interferences are also described in clause4 of ISO10101-1. Clause 4 of ISO10101-1:1993 describes interfering substances which may be present in natural gas and corrections for the interference of hydrogen sulfide and mercaptans. 4 Reagents 4.1 Kark Fischer
31、reagent, of which the water equivalent is approximately5mg/ml. NOTE 1For most applications, commercially available KarlFischer reagent with a water equivalent of approximately5mg/ml has been found adequate. The reagent may be provided as two solutions which are mixed before use. If required, make up
32、 the reagent in the following way. 4.1.1 Components 4.1.1.1 Methanol, with a water content of less than0,01% (m/m). Use commercially available dry methanol or methanol dried in the laboratory by one of the following procedures. a) Place 2litres of methanol in a two-neck3litres flask and add10g of ma
33、gnesium turnings. Add a crystal of iodine, connect the flask to a reflux condenser and leave overnight. Next day, add a further5g of magnesium turnings and reflux for1h. Connect the top of the reflux condenser to a still head, a double surface condenser and a collection flask. Disconnect the water f
34、low through the condenser originally used for reflux, and distil the contents of the flask. Discard the first150ml of condensate. Distil the rest into dried1litre flasks. Vent the system through a drying tube during distillation. b) Dry the methanol over a freshly activated molecular sieve 1) . 4.1.
35、1.2 2-Methoxyethanol, with a water content of less than0,01% (m/m). NOTE 2This can be used as an alternative to methanol(4.1.1.1), with a lower vapour pressure and therefore less losses due to evaporation during sampling of the gas. 4.1.1.3 Pyridine, anhydrous. 4.1.1.4 Sulfur dioxide, liquefied and
36、dry. 4.1.1.5 Iodine. 1) Molecular sieves of type4A(0,4nm pore diameter) or type5A(0,5nm pore diameter) are an examples of a suitable products available commercially. This information is given for the convenience of users of this part of ISO10101 and does not constitute an endorsement by ISO of these
37、 products.ENISO10101-2:1998 4 BSI 05-1999 4.1.2 Preparation Measure 300ml of dry methanol (4.1.1.1) or2-methoxyethanol (4.1.1.2) and110ml of anhydrous pyridine (4.1.1.3) into a750ml conical flask. Slowly pass liquid sulfur dioxide (4.1.1.4) into this solution, mixing carefully until the increase in
38、weight is43 g. Cool this solution in a freezing mixture. When cool, add sufficient iodine (4.1.1.5) to give a permanent light brown colour. Then add63g of iodine and swirl until dissolved. Make up to500ml with dry methanol or2-methoxyethanol. Leave standing in the stoppered conical flask for24h befo
39、re use. NOTE 3If required, the reagent may be diluted with pyridine. NOTE 4For the determination of very small amounts of water, is preferable to use freshly prepared reagent. NOTE 5Commercial reagents, when aged, may give a slow response near the end point. 4.2 Absorbent solution, prepared in the f
40、ollowing way. 4.2.1 Components 4.2.1.1 Ethylene glycol, with a water content less than0,1% (m/m). 4.2.1.2 Sulfur dioxide, liquefied and dry. 4.2.1.3 Pyridine, anhydrous. 4.2.1.4 Karl Fischer reagent, (see 4.1). 4.2.2 Preparation Slowly add 20g of sulfur dioxide (4.2.1.2) to180ml of anhydrous pyridin
41、e (4.2.1.3), while mixing carefully (solution A). To prepare the absorbent solution, add55ml of dry ethylene glycol (4.2.1.1),55ml of Karl Fischer reagent (4.2.1.4) and73ml of solution A to a round bottomed flask. Boil under reflux for10min with a drying tube on the condenser, and then cool. 5 Appar
42、atus 5.1 Karl Fischer apparatus, as described in Annex A. 5.2 Wet-test gas meter, accurate to 1% of the volume passed. 5.3 Guard tube, or Durand bottle, packed with anhydrous calcium chloride (or another suitable drying agent). NOTE 6This is used to prevent back diffusion of water vapour from the ga
43、s meter to the titration cell. 5.4 Titration cell, as shown in Figure A.1. 5.5 Glass syringe, of20ml. NOTE 7Absorbent solution is most easily added to and removed from the cell by means of a20ml graduated syringe with a6% (Luer) fitting and hypodermic needles of suitable length and1mm to2mm bore. 5.
44、6 Syringe, with a fixed needle, of104l, for standardization of the Karl Fischer reagent. 6 Standardization of the Karl Fischer reagent Standardize the Karl Fischer reagent daily or before use, as appropriate. 6.1 Using a dry syringe, introduce sufficient absorbent solution (4.2) to cover the electro
45、des in the apparatus (5.1). Switch on the apparatus and start the stirrer motor. Add the Karl Fischer reagent (4.1) until the needle settles down at a position near zero. When this point is reached, cease additions, since additions of large amounts of reagent will only move the electrometer about0,0
46、2V. To achieve maximum sensitivity at this first stable point, adjust the zero control until the electrometer needle is at zero. Shake the cell several times so that all the internal surfaces are wetted. Once again, adjust to the zero position by adding more reagent. Repeat the procedure until the n
47、eedle remains steady at the zero position for at least30s. NOTE 8The meter needle will remain at zero for at least30s when the titration end point is reached. 6.2 Using the104l syringe (5.6), add exactly10l of distilled water to the contents of the cell (5.4) (withthe syringe needle below the surfac
48、e of the absorbent solution titrate to the zero position and note the volume of reagent used. Once again, shake the cell several times and if the electrometer needle shifts, titrate back to zero. Ignore this additional volume of Karl Fischer reagent; it represents any water which may have entered th
49、e cell as vapour while the104l of water was being added. 6.3 Add a further104l of water to the cell, and again titrate to the zero position. Take an average of the two titrations. If the variation is greater than2%, discard the contents of the cell. Introduce a further portion of absorbent solution into the cell and repeat the standardization procedure. If the titration for two further104l portions of distilled water still varies by more than2%, it is likely that the Karl Fischer reagent has aged and needs replacing wi
