BRITISH STANDARD
Methods for
Analysis and testing of coal and coke — Part 104: Proximate analysis — Section 104.2 Determination of moisture content of the general analysis sample of coke
BS 10 1016 16-1 -104 04.2: .2: 1991
BS 1016-104.2:1991
Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Solid Mineral Fuels Standards Policy Committee (SFC/-) to Technical Committee SFC/3, upon which the following bodies were represented: British Cement Association British Coal Corporation British Gas plc British Steel Industry Department of Trade and Industry (Standards and Quality Policy Unit, Quality, Design and Education Division) Electricity Supply Industry in United Kingdom GAMBICA (BEAMA Ltd.) Institute of British Foundrymen Institute of Petroleum Power Generation Contractors’ Association (BEAMA Ltd.)
This British Standard, having been prepared under the direction of the Solid Mineral Fuels Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 30 April 1991 © BSI 07-1999 First published as BS 1016-4, March 1942 Second edition May 1957 Third edition October 1965 Fourth edition October 1973 Fifth edition as BS 1016-104.2, April 1991
The following BSI references relate to the work on this standard: Committee reference SFC/3 Draft for comment 90/53515 DC
ISBN 0 580 19470 1
Amendments issued since publication Amd. No.
Date
Comments
BS 1016-104.2:1991
Contents
Committees responsible Foreword 0 1 2 3 4 5 6 7 8 9 10
Introduction Scope Definitions Principle Reagent Apparatus Preparation of test sample Procedure Expression of results Precision Test report
Publication(s) referred to
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BS 1016-104.2:1991
Foreword This Section of BS 1016 has been prepared under the direction of the Solid Mineral Fuels Standards Policy Committee. Part 104 is a revision of the 1973 editions of BS 1016-3 and BS 1016-4, which are superseded and withdrawn. This Section replaces clause 4 in BS 1016-4:1973, from which the principal changes are the omission of the direct gravimetric method (in 4.2) and the replacement of drying in nitrogen (in 4.3) by heating in air and then cooling in nitrogen. Part 104 is a further Part numbered under a scheme for rationalizing and restructuring BS 1016. The new series, when complete, will begin with Part 100, which will include a general introduction. The earlier series of Parts is as follows, with the new Part numbers (which will b e given to revisions when they are published) in parentheses. — Part 1: Total moisture of coal (Part 101); — Part 2: Total moisture of coke (Part 102); — Part 5: Gross calorific value of coal and coke (Part 105); — Part 6: Ultimate analysis of coal (Part 106); — Part 7: Ultimate analysis of coke (Part 106); — Part 8: Chlorine in coal and coke (Part 106); — Part 9: Phosphorus in coal and coke (Part 106); — Part 10: Arsenic in coal and coke (Part 106); — Part 11: Forms of sulphur in coal (Part 106); — Part 12: Caking and swelling properties of coal (Part 107); — Part 13: Tests special to coke (Part 108); — Part 14: Analysis of coal ash and coke ash (Part 114); — Part 15: Fusibility of coal ash and coke ash (Part 113); — Part 16: Methods for reporting results (Part 100); — Part 17: Size analysis of coal (Part 109); — Part 18: Size analysis of coke (Part 110); — Part 20: Determination of Hardgrove grindability index of hard coal (Part 112); — Part 21: Determination of moisture-holding capacity of hard coal (Part 103). The following Parts in the new series have been published. — Part 104: Proximate analysis; — Part 111: Determination of abrasion index of coal. Part 104 is divided into four Sections as follows. — Section 104.1: Determination of moisture content of the general analysis sample of coal; — Section 104.2: Determination of moisture content of the general analysis sample of coke; — Section 104.3; Determination of volatile matter content; — Section 104.4: Determination of ash. This Section is related to ISO 687:1974, published by the International Organization for Standardization (ISO). The principal difference is that in the method described in ISO 687 the weighing dish is cooled in a desiccator instead of in an atmosphere of nitrogen.
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There may be alternative methods for carrying out this determination which are more rapid and/or less labour-intensive than the reference method described in this Section of BS 1016. Work is in hand on the preparation of a standard for the validation of such alternative methods. It is important to demonstrate that an alternative method is free from bias when compared to this reference method, an d will give a level of repeatability which is the same as or better than that quoted for the reference method (see clause 9). WARNING NOTE. This British Standard does not necessarily detail all the precautions necessary to comply with the requirements of the Health and Safety at Work etc. Act 1974 or the Control of Substances Hazardous to Health Regulations 1988. Attention should be paid to any appropriate precautions and the method should be operated only by trained personnel. 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 pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 and 2, 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.
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0 Introduction As coke is hygroscopic, its moisture content will vary with change of humidity of the atmosphere. Therefore, the moisture in the general analysis sample has to be determined whenever portions are weighed out for other analytical determinations (for example, volatile matter content, calorific value, cabon and hydrogen content) and when results are required on a dry basis. If all the portions taken for analysis are weighed out on the same day and at about the same time, one test for moisture content should suffice.
1 Scope This Section of BS 1016 describes a reference method for determining the moisture content of the general analysis sample of coke. NOTE The titles of the publications referred to in this standard are listed on the inside back cover.
5.4 Cooling vessel, with provision for the nitrogen to pass through it at about 15 volumes per hour. NOTE The provision of a metal plate, preferably of aluminium, inside the vessel will increase the rate of cooling.
6 Preparation of test sample The coke used for the determination of moisture content is the general analysis sample, ground to pass a sieve of 212 È m aperture (see BS 1017-2). Expose the sample in a thin layer for the minimum time required for the moisture content to reach approximate equilibrium with the laboratory atmosphere. Immediately before weighing out the test portion (see 7.1), mix the test sample for not less than 1 min, preferably by mechanical means.
7 Procedure 7.1 Test portion
For the purposes of this Section of BS 1016, the definitions given in BS 1017-2 apply, together with the following.
Weigh, to the nearest 0.1 mg, a clean, dry, empty weighing dish (5.3) with its cover. Add 1 g to 2 g of the test sample to the dish in an even layer and reweigh the dish, cover and test portion to the nearest 0.1 mg.
moisture in the general analysis sample
7.2 Determination
moisture content of the general analysis sample of a solid mineral fuel after it has attained approximate equilibrium with the atmosphere in the laboratory and which is removable under specified conditions
Transfer the dish containing the test portion (see 7.1), without its cover, to the oven (5.2), preheated to a temperature within the range 190 C to 210 C (see note 1), and heat the dish at that temperature for a minimum of 60 min (see notes 2 and 3). Remove the dish from the oven and replace its cover. Transfer the dish to the cooling vessel (5.4) through which the nitrogen (4.1) is passing at about 15 volumes per hour, and weigh the dish, to the nearest 0.1 mg, when cool.
2 Definitions
3 Principle A known mass of the coke is heated in air at between 190 C and 210 C (see note 1 to 7.2) and maintained at this temperature until constant in mass. The moisture content is calculated from the loss in mass of the coke. °
°
4 Reagent 4.1 Nitrogen, dry and containing less than 10 È L of oxygen per litre.
5 Apparatus
°
°
For further periods each of at least 10 min, reheat the dish without its cover at the same temperature as before, then cool and reweigh it with its cover to the nearest 0.1 mg, until any further change in mass on successive weighings does not exceed 1 mg. NOTE 1 The time taken for the determination can be considerably shortened if drying is carried out at a temperature of 320 C in an atmosphere of nitrogen, when heating for 1 h will usually suffice. NOTE 2 The mass per unit area of the coke layer may be increased up to 0.25 g/cm2, provided that the heating time is increased sufficiently (see note 3). NOTE 3 Heating for 4 h is normally sufficient if the mass of coke per unit area does not exceed 0.15 g/cm2, but if the mass per unit area is 0.25 g/cm2, 6 h will probably be required. °
5.1 Balance, capable of weighing to the nearest 0.1 mg. 5.2 Air oven, capable of maintaining a temperature within the range 190 C to 210 C (see note 1 to 7.2) and in which the atmosphere changes from 3 times to 8 times per hour. °
°
5.3 Weighing dishes, shallow, of glass with ground-on covers or of corrosion-resistant metal with well-fitting covers, of such a size that the mass of coke per unit area does not exceed 0.15 g/cm2 (see note 2 to 7.2).
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8 Expression of results
10 Test report
The moisture content of the coke, expressed as a percentage by mass, is given by the formula:
The test report shall include the following:
m 2 – m 3 ---------------------- ´ 100 m 2 – m 1 where
a) the identification of the sample; b) the reference to the method used, i.e. BS 1016-104.2:1991; c) the results expressed in accordance with clause 8;
m1 is the mass of the empty dish plus cover (in g);
d) any unusual features noted during the determination;
m2 is the mass of the dish plus cover plus coke before heating (in g);
e) any operations not specified in this standard or regarded as optional.
m3 is the mass of the dish plus cover plus coke after heating (in g). Report the result to the nearest 0.1 % (m/m). NOTE It is recommended that the result is calculated as the mean of duplicate determinations.
9 Precision 9.1 Repeatability The results of duplicate determinations, carried out in the same laboratory by the same operator with the same apparatus on representative portions weighed out at the same time from the same test sample, should not differ by more than 0.1 % (m/m). 9.2 Reproducibility Since the humidity conditions in different laboratories will vary, it is not practical to quote a limiting value for reproducibility.
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BS 1016-104.2:1991
Publication(s) referred to BS 1017, Sampling of coal and coke. BS 1017-2, Methods for sampling of coke. ISO 687, Coke — Determination of moisture in the analysis sample 1).
1)
Referred to in the foreword only.
© BSI 07-1999
BS 1016-104.2: 1991
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