BS 1016-106 4 2-1996 Methods for analysis and testing of coal and coke - Ultimate analysis of coal and coke - Determination of total sulfur content - High temperature combustion me.pdf

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1、BRITISH STANDARD BS 1016-106.4.2: 1996 ISO 351:1996 Incorporating corrigendum 1:1996 Methods for Analysis and testing of coal and coke Part 106: Ultimate analysis of coal and coke Section 106.4 Determination of total sulfur content Subsection 106.4.2 High temperature combustion method. ICS 75.160.10

2、BS 1016-106.4.2:1996 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes intoeffect on 15 October 1996 BSI 11-1998 The following BSI references relate to the work on this s

3、tandard: Committee reference SFI/3 Draft for comment 93/508885 DC ISBN 0 580 26461 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee SFI/3 Analysis and testing of coal and coke, upon which the following bodies were repres

4、ented: British Cement Association British Coal Corporation British Iron and Steel Producers Association Electricity Association GAMBICA (BEAMA Ltd.) Power Generation Contractors Association (PGCA (BEAMA Ltd.) Amendments issued since publication Amd. No Date CommentsBS 1016-106.4.2:1996 BSI 11-1998 i

5、 Contents Page Committees responsible Inside front cover National foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reactions 1 5 Reagents 1 6 Apparatus 2 7 Preparation of test sample 4 8 Procedure 4 9 Blank test 5 10 Expression of results 5 11 Precision 5 12 Test report

6、5 Figure 1 Arrangement of furnace and absorption train 3 Table 1 6BS 1016-106.4.2:1996 ii BSI 11-1998 National foreword This British Standard has been prepared by SFI/3 and is identical to ISO351:1996 Solid mineral fuels Determination of total sulfur High temperature combustion method, including Cor

7、rigendum 1:1996, published by the International Organization for Standardization (ISO) and in the preparation of which the UK played a full part. BS 1016-106 will form a revision of Parts 6 to 11 of BS 1016. This Subsection supersedes the following. In BS 1016-6:1977, clause 5, subclause 8.3 and tho

8、se parts of clause 11 which refer to sulfur; In BS 1016-7:1977, clause 5, subclause 8.3 and those parts of clause 10 which refer to sulfur. Principal differences are the allowance of an alternative layout for the absorbers, recommendation of an alternative rate of combustion for certain types of coa

9、l and coke and modification of the precision requirements for the method with respect to higher sulfur content coals. An alternative method is given in BS 1016-106.4.1 ESHKA method. BS 1016-106 is part of a rationalized and restructured BS 1016. The Parts numbered from 1 to 21 are gradually being wi

10、thdrawn and replaced by Parts in the new series. The full list of Parts in the new series, together with corresponding numbering of the old series and related international standards is given in BS 1016 Analysis and testing of coal and coke Part 100:1994 General introduction and methods for reportin

11、g results. The Technical Committee has reviewed the provisions of ISO 1015:1975, ISO5068:1983 and ISO 5069-2:1983 to which normative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. British Standards related to ISO 331:1983, ISO 587:1

12、981, ISO 687:1974, ISO1170:1977, ISO 1988:1975 and ISO 2309:1980 are BS 1016 Methods for analysis and testing of coal and coke Section 104.1:191 Determination of the moisture content of the general analysis sample of coal, Part 8:1977 Chlorine in coal and coke, Section 104.2:1991 Determination of th

13、e moisture content of the general analysis sample of coke, Part 100:1994 General introduction and methods for reporting results, BS 1017 Sampling of coal and coke Part 1:1989 Methods for sampling of coal and Part 2:1994 Methods for sampling of coke respectively. ISO 2309 is being revised in conjunct

14、ion with ISO 1988 Hard coal Sampling, ISO 9411 Solid mineral fuels Mechanical sampling from moving streams Part1: Coal and Part 2: Coke. This revision will be published in eight Parts, and it is intended to implement these Parts as identical British Standards, superseding BS 1017. A British Standard

15、 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

16、inside front cover, pages i and ii, pages1 to 6 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.BS 1016-106.4.2:1996 BSI 11-1998 1 Introduction An alternative metho

17、d to that specified in this International Standard is given in ISO 334:1992, Solid mineral fuels Determination of total sulfur Eschka method. 1 Scope This International Standard specifies a method of determining the total sulfur content of hard coal, brown coal and lignite, and coke by high temperat

18、ure combustion. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreemen

19、ts based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 331:1983, Coal Determination of moisture in the analy

20、sis sample Direct gravimetric method. ISO 587:1981, Solid mineral fuels Determination of chlorine using Eschka mixture. ISO 687:1974, Coke Determination of moisture in the analysis sample. ISO 1015:1992, Brown coals and lignites Determination of moisture content Direct volumetric method. ISO 1170:19

21、77, Coal and coke Calculation of analyses to different bases. ISO 1988:1975, Hard coal Sampling. ISO 2309:1980, Coke Sampling. ISO 5068:1983, Brown coals and lignites Determination of moisture content Indirect gravimetric method. ISO 5069-2:1983, Brown coals and lignites Principles of sampling Part

22、2: Sample preparation for determination of moisture content and for general analysis. 3 Principle A known mass of a sample of coal or coke is burnt in a stream of oxygen, in a tube furnace at a temperature of 1350 C. The acid gases formed (chlorine and oxides of sulfur) are absorbed in hydrogen pero

23、xide and subsequently determined titrimetrically. A correction is made to take account of any chlorine liberated and a suitable combustion additive prevents the retention of sulfur in the ash. 4 Reactions 4.1 SO 2+ H 2 O 2 H 2 SO 4 4.2 Cl 2+ H 2 O 2 2HCl + O2 4.3 Na 2 B4O 7+ 2HCl + 5H 2 O 2NaCl + 4H

24、 3 BO 3 4.4 Na 2 B4O 7+ H 2 SO 4+ 5H 2 O 2NaCl + 4H 3 BO 3 4.5 NaCl + Hg(OH)CN NaOH + HgClCN 4.6 2NaOH + H 2 SO 4 Na 2 SO 4+ 2H 2 O 5 Reagents WARNING Care should be exercised when handling reagents, many of which are toxic and corrosive. During the analysis, unless otherwise stated, use only reagen

25、ts of recognized analytical grade and only distilled water or water of equivalent purity. 5.1 Aluminium oxide (alumina), finely divided. 5.2 Hydrogen peroxide, approximately 3% (m/m) neutral solution. Dilute 100 ml of 30% (m/m) hydrogen peroxide solution to 1 litre with water and neutralize with the

26、 sodium tetraborate solution (5.4) using the mixed indicator (5.6). 5.3 Mercury(II) oxycyanide, saturated solution at20C, approximately 45 g/l. Saturate a suitable volume of water with mercury(II) oxycyanide by prolonged agitation; filter and neutralize the filtrate with the sulfuric acid (5.5), usi

27、ng bromothymol blue as an external indicator. Store in a dark glass bottle; do not keep for more than 4 d. 5.4 Sodium tetraborate, standard volumetric solution, c(Na 2 B 4 O 7 ) = 0,025 mol/l. Dissolve 9,534 2 g of sodium tetraborate decahydrate in water and dilute to 1 litre. Mix thoroughly. 5.5 Su

28、lfuric acid, standard volumetric solution, c(H 2 SO 4 ) = 0,012 5 mol/l.BS 1016-106.4.2:1996 2 BSI 11-1998 5.6 Mixed indicator solution 5.6.1 Solution A Dissolve 0,125 g of 2-(4-dimethylaminophenylazo) benzoic acid, sodium salt (methyl red) in 100 ml of water. 5.6.2 Solution B Dissolve 0,083 g of 3,

29、7-bis(dimethylamino) phenothiazine-5-ylium chloride (methylene blue) in100 ml of water. Store in a dark bottle. 5.6.3 Mixed solution Mix equal volumes of solution A and solution B. Store in a dark bottle. Discard the mixed solution after 1 week. 5.7 Oxygen, laboratory grade, of purity at least99,6%

30、(m/m). 5.8 Sodium hydroxide on an inert base, preferably of a coarse grading, for example 1,2 mm to 1,7 mm, and preferably of the self-indicating type. 6 Apparatus 6.1 Analytical balance, capable of weighing to the nearest 0,1 mg. 6.2 Graduated glassware, conforming to the requirements for class A i

31、n the International Standards prepared by ISO/TC 48, Laboratory glassware and related apparatus. 6.3 Furnace, capable of heating a tube, of approximately 28 mm external diameter over a length of 125 mm to 150 mm, to a temperature of1350 C. The furnace may be heated electrically, using either silicon

32、 carbide resistance rods (controlled by a variable transformer) or a resistance wire (controlled by a variable resistance). 6.4 Combustion tube, of approximately 28 mm external diameter, 3 mm wall thickness and650mm length, made of aluminous porcelain which is impervious to gases up to the working t

33、emperature (see Figure 1). A straight tube is most convenient and may be used in conjunction with an adapter of fused silica having a bell-shaped end, which gives a narrow clearance from the inner wall of the heated tube, and a heat-resistant stopper (acrylonitrile or chloroprene is suitable). Alter

34、natively, the tube may have, a beak end, at the exit, with a tubulure to enable condensation products to be washed out after a test; or a straight tube of aluminous porcelain may be used in conjunction with a borosilicate glass adapter, having a cap-shaped end which fits onto the outer wall of the t

35、ube. In this case it will be necessary to lag the end of the combustion tube with a suitable heat-resistant mineral fibre to prevent condensation in the tube. 6.5 Oxygen cylinder, fitted with a needle valve to control the rate of flow of oxygen (5.7), and a flowmeter to measure up to 300 ml/min. The

36、 oxygen should, as a precautionary measure, be passed through a U-tube packed with sodium hydroxide on an inert base (5.8). 6.6 Combustion boat, of iron-free, unglazed porcelain, of minimum dimensions 45 mm long,12,5mm wide and 10 mm deep, for hard coal and coke samples, and approximately 75 mm long

37、,15 mm wide and 10 mm deep for brown coal and lignite. 6.7 Heat-resistant wire, approximately 2 mm thick and 450 mm long, with a bent end to transfer the used boat from the combustion tube onto a rigid refractory sheet. 6.8 Silica or steel pusher, made from rod or sealed tube, approximately 6 mm in

38、diameter and 450 mm long, with a disc end 12 mm in diameter, for pushing the boat into the hot zone of the combustion tube. The pusher passes loosely through a glass or metal T-piece, one end of which fits into the rubber stopper which closes the inlet end of the combustion tube, the other being sea

39、led by a rubber sleeve (see note1) through which the pusher slides. The sleeve prevents the escape of oxygen, which enters at the stem of the T-piece. The pusher is usually marked from the disc end, for convenience in ascertaining the position of the boat in the combustion tube during pushing. NOTE

40、1The rubber sleeve should be changed periodically to avoid leakage.BS 1016-106.4.2:1996 BSI 11-1998 3 Figure 1 Arrangement of furnace and absorption trainBS 1016-106.4.2:1996 4 BSI 11-1998 6.9 Two absorbers, of capacity about 150 ml, which may be large boiling tubes, wide-necked bottles or Dreschel

41、bottles, each containing a sintered glass disc of 0,015 mm to 0,040 mm maximum pore size in the gas distribution tube. The diameter of the absorber shall be such that the disc is covered to a depth of at least 25 mm by the absorbing solution. Connect the silica adapter, or the reaction tube fitted w

42、ith a tubulure, to the first absorber. Connect this in series with the second absorber. Alternatively, use a single narrow absorber about35mm in diameter and 150 mm deep, so that the bubbler disc (0,015 mm to 0,040 mm maximum pore size) is covered to a depth of at least 90 mm. To avoid leakage at th

43、e rubber sleeve of the inlet end due to the resistance of the sintered glass bubbler, connect the second absorber to a suction-pump through a pressure regulator adjusted to maintain slight suction at the inlet end of the combustion tube. A convenient assembly of the apparatus is illustrated in Figur

44、e 1. 7 Preparation of test sample Prepare the test sample for general analysis in accordance with ISO 1988, ISO 2309 or ISO 5069-2, as appropriate. Ensure that the moisture content of the sample is in equilibrium with the laboratory atmosphere, exposing it, if necessary, in a thin layer for the mini

45、mum time required to achieve equilibrium. Before commencing the determination, thoroughly mix the test sample for at least 1 min, preferably by mechanical means. If the results are to be calculated other than on an “air-dried” basis (see clause 10), after weighing the test portion (see clause 8), de

46、termine the moisture content using a further portion of the test sample by the method described in ISO 331, ISO 687, ISO 1015 or ISO 5068, as appropriate. A further portion should be set aside if the determination of chlorine by the Eschka method (ISO 587) is required. 8 Procedure Raise the temperat

47、ure of the furnace (6.3) to1350C. Weigh, to the nearest 0,1 mg, about0,5g of the test sample (clause 7) and transfer to a combustion boat (6.6), taking care to spread uniformly. Cover evenly with about 0,5 g of the aluminium oxide (5.1). Measure 100 ml of the hydrogen peroxide solution (5.2) and eit

48、her divide this amount between the two absorbers (6.9) or pour it all into the single absorber. Adjust the suction-pump and pressure regulator (see 6.9) so that a rapid stream of air is drawn at constant pressure through the absorber(s). Insert the silica adapter into the combustion tube (6.4) and s

49、ecure the stopper. Adjust the oxygen (5.7) flow to300 ml/min. Insert the charged boat from the inlet end of the combustion tube so that its centre is 240 mm from the centre of the hottest zone and secure the stopper carrying the pusher (6.8) and the oxygen inlet. After1 min, move the boat forward 40 mm. At the end of each of the next five 1 min periods, push the boat forward about 40 mm, pulling back the pusher each time to prevent distortion. After the last push, the boat should be at the centre of the hottest zone