1、ICS 75.160.10Prfung fester Brennstoffe Bestimmung des Gehaltes an Kohlenstoffund Wasserstoff Verfahren nach Radmacher-HoverathIn keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.Ref
2、. No. DIN 51721 : 2001-08English price group 06 Sales No. 010602.02DEUTSCHE NORM August 200151721Continued on pages 2 to 5. No part of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the e
3、xclusive right of sale for German Standards (DIN-Normen).Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.Determining the carbon and hydrogencontents of solid fuel by theRadmacher-Hoverath methodSupersedes DIN 51721,August
4、 1950 edition.ForewordThis standard has been prepared by Technical Committee Prfung fester Brennstoffe of theNormenausschuss Materialprfung (Material Testing Standards Committee).AmendmentsThis standard differs from the August 1950 edition as follows:a) a preliminary degassing procedure has been int
5、roduced;b) the standard has been editorially revised and brought into line with current standards practice.Previous editionDIN 51721: 1950-08.1 ScopeThe method described in this standard serves to determine the total carbon and hydrogen contents of hardcoal, brown coal and lignite, and coke; it may
6、also be applied to liquid fuel. It is classed as a reference methodfor instrumental methods of determining carbon and hydrogen contents.Knowledge of the carbon and hydrogen contents is required when determining how balanced the elementalcontents are.NOTE: The method determines not only organic carbo
7、n, but also mineral carbonates. The content of organiccarbon can be calculated by determining carbon in the carbonates as specified in DIN 51726.Similarly, the method permits the determination not only of organic hydrogen, but also of the hydrogenpresent in the moisture and in the minerals (water of
8、 crystallization). The former can be allowed for bydetermining the moisture content as specified in DIN 51718 at the same time as determining the totalhydrogen content and including the result in calculating the bound hydrogen. The hydrogen in the water ofhydration cannot be determined directly.2 No
9、rmative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions
10、of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies (including amendments).Page 2DIN 51721 : 2001-08DIN 51701-3 Sampling of solid fuels Sample preparationDIN 51718 D
11、etermination of water content and of analytical moisture content of solid fuelDIN 51726 Determination of the carbonate carbon dioxide content of solid fuelsDIN EN ISO 4259 Petroleum products Determination and sampling of precision data in relation to methodsof test (ISO 4259 : 1992 + Corr 1 : 1993)3
12、 PrincipleThe fuel sample is placed in a reaction tube and degassed in the degassing zone. The substances evolved areconveyed in an inert gas (nitrogen) through a heated capillary into the combustion zone, where they are burntin excess oxygen. When degassing is complete, the solid residues are burnt
13、 by passing oxygen into thedegassing zone. The combustion products are passed through a lead dioxide layer at 200 C to absorb sulfuroxides, nitrogen oxides and halogens, while the water and carbon dioxide produced are absorbed anddetermined gravimetrically.4 ApparatusThe following equipment shall be
14、 used.4.1 Combustion assembly, consisting ofa) a reaction tube, heated by two gas burners (see figure 1);b) absorption train, for absorbing the combustion products (see figure A.1).Figure 1: Reaction tube4.2 Platinum, porcelain or silica combustion dish or boat, about 70 mm long.New combustion vesse
15、ls shall be roasted before being used for the first time.4.3 Analytical balance, capable of weighing to an accuracy of 0,1 mg.4.4 Flowmeter.4.5 Purification train, containing sodium hydroxide and magnesium perchlorate retained by a layer of inertmaterial.5 Reagents5.1 GeneralThe following analytical
16、 grade reagents shall be used.6 Oxygen inlet7 9 cm absorption zone8 11 cm combustion zone9 13 cm degassing zoneKey1 Quartz wool2 Silicone oil3 Lead dioxide4 Partition5 Dividing wall with capillaryPage 3DIN 51721 : 2001-08()122927mmw = ,C(tot)5.2 Anhydrous magnesium perchlorate (absorbent No. 1), hav
17、ing a particle size of 0,8 mm to 2,5 mm.Spent magnesium perchlorate shall not be regenerated.5.3 Sodium hydroxide (absorbent No. 2), in layers having particle sizes of 0,8 mm to 1,6 mm and 1,6 mm to3 mm, respectively, retained by a layer of inert material.5.4 Lead dioxide, prepared by processing lea
18、d dioxide powder with water to form a thick paste, applying anapproximately 10 mm thick layer of the latter to a 2 mm analytical sieve, drying it for about 12 hours at 250 C,carefully reducing the dried material in size, drying it again at 200 C and then removing fines by sieving througha 1,6 mm sie
19、ve.5.5 Auxiliary materials, comprising clay shards, cotton wool, quartz wool and silicone oil.6 ProcedureWeigh about 200 mg of finely divided analytical sample material prepared as in DIN 51701-3 into a combustionboat, to an accuracy of 0,1 mg. Prepare and test the serviceability of the absorption v
20、essels as described inAppendix A and, after weighing them to an accuracy of 0,1 mg, connect them to the equipment. Adjust the gasburners that heat the combustion tube so that a temperature of (200 t 5) C is maintained in the absorptionzone.Push the boat into the hot degassing zone and seal the tube
21、with a ground glass stopper having an inlet throughwhich nitrogen is to be passed at an initial rate of 25 ml/min.Adjust the oxygen flow through an inlet directly into the combustion zone to a rate of 120 ml/min, then carefullydegas the fuel and pass the products into the combustion zone to ignite t
22、hem. Ensure that the degassing ofthe sample is slow and uniform and that the flame is soot-free. To complete the combustion of the fuel, use thethree-way stopcock to pass oxygen into the degassing zone. After combustion, continue flushing for a furtherfive minutes with oxygen, then, after disconnect
23、ing the absorption vessels, cool and weigh them. Reset thethree-way stopcock so that nitrogen again flows into the degassing zone.Calculate the carbon and hydrogen contents, as percentages, from the difference in the mass of the vesselsand the initial sample mass.7 Expression of resultsCalculate the
24、 total carbon content, w(C(tot), of the sample, as a percentage by mass, using equation (1):(1)wherem1is the initial sample mass, in g;m2is the blank-corrected increase in mass of the K-type absorption vessel, in g.Calculate the organic carbon content, w(C(org), as a percentage by mass, by subtracti
25、ng the carbon in thecarbonates from the total carbon, using equation (2):(2)wherew(C(tot) is the total carbon content, as a percentage by mass;w(CO2) is the carbon dioxide content determined as in DIN 51726, as a percentage by mass.Calculate the total hydrogen content, w(H(tot), of the sample, as a
26、percentage by mass, using equation (3):(3)wherem1is the initial sample mass, in g;m3is the blank-corrected increase in mass of the W-type absorption vessel, in g.Calculate the anhydrous hydrogen content, w(H(an), by subtracting the hydrogen content due to the moisturefrom the total hydrogen content,
27、 using equation (4):(4)where()() ()292720 CO,CC(tot)(org)www -=()131911mmw = ,H(tot)()() ()A,HH(tot)(an)www -= 91110w(H(tot) is the total hydrogen content, as a percentage by mass;w(A) is the moisture content, as a percentage by mass.Report the result to two decimal places.8 Precision(cf. DIN EN ISO
28、 4259)Repeatability limit(same operator, same equipment)If two results are obtained under repeatability conditions, both results shall be considered acceptable and inconformity with this standard if they differ by no more than the values given in the second column of table 1.Reproducibility limit(di
29、fferent operators, different equipment)If two separate laboratories each obtain a result under reproducibility conditions, both results shall beconsidered acceptable and in conformity with this standard if the mean values of the two results differ by nomore than the values given in the third column
30、of table 1.Table 1: Precision9 Instrumental methodsIf instrumental methods are used, it shall be demonstrated that the results do not differ systematically fromthose obtained by the method described in this standard and that the precision will be as good as or better thanthe values reported here.App
31、endix APreparing and testing the serviceability of absorption vesselsA.1 K-type vesselK-type vessels are used to determine carbon dioxide by absorption on sodium hydroxide retained by a layerof inert material (absorbent No. 2).PreparationPour first the coarse absorbent No. 2 (particle sizes 1,6 mm t
32、o 3 mm), then the finely divided absorbent No. 2(particle sizes 0,8 mm to 1,6 mm) evenly on the layer of clay shards, keeping compaction to a minimum. Theninsert a layer of cotton wool (see figure A.1) before adding a layer of absorbent No. 1.How complete the absorption is will be determined by the
33、ratio of coarse to fine absorbent No. 2 and the depthof the absorbent No. 1 layer.NOTE: The reaction of carbon dioxide with sodium hydroxide produces lumps in the coarse packing due to theformation of water and, since this results in incomplete absorption, it is advisable to add a further K-typeabso
34、rption vessel.A.2 W-type vesselW-type vessels are used to absorb water on magnesium perchlorate (absorbent No. 1).PreparationPlace a layer of cotton wool at the bottom of the vessel and pour absorbent No. 1 (particle sizes 0,8 mm to2,5 mm) on it evenly, keeping compaction to a minimum. Then, add a f
35、urther layer of cotton wool.Page 4DIN 51721 : 2001-08Repeatability limit, as apercentage (absolute)Reproducibility limit, as apercentage (absolute)CarbonHydrogenElementPage 5DIN 51721 : 2001-08Key1 Cotton wool2 Clay shards3 Absorbent No. 2 (particle sizes of 1,6 mm to 3 mm)4 Absorbent No. 2 (particl
36、e sizes of 0,8 mm to 1,6 mm)5 Absorbent No. 1Figure A.1: Absorption trainA.3 Serviceability testingA.3.1 GeneralThe depth and condition of absorbent packings shall be such that the specified flow rate can be maintainedif one W-type vessel and two K-type vessels are combined to form a train.A.3.2 W-t
37、ype vessel testWeigh about 200 mg of a hydrogen-rich coal and burn it by the method described (see clause 6), using only aW-type vessel. The packing of the vessel may be deemed adequate if, when two vessels are connected in series,there is no marked increase in the mass of the second vessel.NOTE: Th
38、is test may also be used to test used W-type vessels for complete absorption.A.3.3 K-type vessel testWeigh about 200 mg of coal and burn it by the method described (see clause 6), using two K-type vessels. Thepacking of the vessel may be deemed adequate if, when the two vessels are connected in series, there is nomarked increase in the mass of the second vessel.K-type vessel W-type vessel
