DIN 51719-1997 Testing of solid fuels - Solid mineral fuels - Determination of ash content《固体燃料试验 固体矿物燃料 灰分含量测定》.pdf

1、ICS 75.160.10Descriptors: Testing, solid fuels, ash content.Prfung fester Brennstoffe Bestimmung des AschegehaltesIn keeping with current practice in standards published by the International Organization for Standardiza-tion (ISO), a comma has been used throughout as the decimal marker.Ref. No. DIN

2、51719 : 1997-07English price group 05 Sales No. 010511.99DEUTSCHE NORM July 199751719Continued on pages 2 and 3. No part of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e.V., Berlin.Beuth Verlag GmbH, D-10772 Berlin, has the exclusive right of s

3、ale for German Standards (DIN-Normen).Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.Determination of ash in solid mineral fuelsSupersedesJune 1978 edition.ForewordThis standard has been prepared by Technical Committee P

4、rfung fester Brennstoffe of the Normen-ausschu Materialprfung (Materials Testing Standards Committee).AmendmentsThis standard differs from the June 1978 edition as follows:a) In accordance with ISO 1171 : 1981, the maximum mass per unit area of the fuel layer in the dishesused for incineration has b

5、een specified as 0,15 g/cm2for coal and as 0,10 g/m2for coke.b) The tolerance on the incineration temperature of 815 C has been reduced to t 10 C.c) The time taken to heat to 500 C has been increased to 60 minutes.d) The results are now to be reported to two decimal places.e) The standard has been e

6、ditorially revised.Previous editionsDIN DVM 3721: 1933-03; DIN DVM 3721 = DIN 53721: 1934-05; DIN 51719: 1950-08, 1967-10, 1978-06.1 ScopeThis standard specifies a method of determining the ash content of solid mineral fuels. It is applicable to hardcoal, coke, brown coal, peat, wood charcoal, and b

7、riquettes made of these materials.2 Normative 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,

8、subsequent amendments to or revisions 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.DIN 1333 Presentation of numerical dataDIN 51700 Testing of solid fuel Gene

9、ral information and overview of methodsDIN 51701-3 Sampling of solid fuels Sample preparationISO 1171 : 1981 Solid mineral fuels Determination of ash contentISO 5725 series Accuracy (trueness and precision) of measurement methods and resultsPage 2DIN 51719 : 1997-073 ConceptAshThe residue present af

10、ter complete combustion of fuel in the air under the conditions specified in this standard.NOTE: The chemical reactions which take place during incineration result in the ash content not being identicalwith the mineral content of the sample 1.4 PrincipleA weighed sample is heated in the presence of

11、air in a specified time to (815 t 10) C, or to (710 t 15) C forwood charcoal and wood briquettes, and incinerated until constant mass is reached.To enable conversion of results to other reference conditions, the moisture content of the sample is determinedat the same time.5 ApparatusThe following eq

12、uipment shall be used.5.1 Analytical balance, with a limit of error of 0,1 mg.5.2 Dishes, made of fused silica, porcelain or platinum, with a depth of 8 to 10 mm, and of a width and lengthsuch that the mass per unit area does not exceed 0,15 g/cm2for coal or 0,10 g/cm2for coke.5.3 Insulating plate,

13、made of ceramic material, having a thickness of 6 mm, or made of heat-resistant steel,of a size which enables it to be easily slid into the muffle furnace.5.4 Muffle furnace, in which a zone large enough to accommodate the dish can be heated to (815 t 10) C.It shall be capable of achieving the heati

14、ng rates specified in clause 7 and the airflow through it shall be suchas to give 5 to 10 air changes per minute.NOTE 1: The number of air changes per minute can be checked using a pitot-static tube and a sensitivemanometer.NOTE 2: A reduced air throughput (e.g. as a result of deposits in the flue p

15、ipe) can lead to erroneous results.It is therefore advisable to check the flue pipe regularly and to clean it if necessary.5.5 Desiccator, without desiccant.6 Sample preparationThe analytical sample shall have a particle size less than 200 mm and shall be prepared as specified inDIN 51701-3.7 Proced

16、ureWeigh an empty dish to the nearest 0,1 mg (mass m1).Weigh (1 t 0,1) g of the prepared sample (see clause 6) into the dish to the nearest 0,1 mg (mass m2) and spreadit evenly.Place the dish containing the sample in the cold furnace (at room temperature or no warmer than 100 C). Cokesamples may be

17、placed in the preheated furnace, in which case the dish containing the sample shall be placedon an insulating plate before being introduced into the furnace.Switch on the furnace and heat at an approximately constant rate to (500 t 10) C over a period of 60 minutes,then to (815 t 10) C and maintain

18、it at the final temperature for not less than 60 minutes.Take the dish together with the ash out of the furnace and place it on a heat-resistant base (e. g. a metal plate)for five to ten minutes to allow it to cool. Then transfer it to a desiccator and reweigh after thermal equilibriumhas been reach

19、ed.NOTE: If the cooling period is too long, the ash may absorb moisture and carbon dioxide and the ash contentmeasured will be too great.Weigh the cooled dish to the nearest 0,1 mg (mass m3). Incineration is complete when the ash contains nounburnt particles. This can be checked by stirring with a p

20、latinum wire.If the sample has not been completely incinerated, heat the dish at (815 t 10) C for a further 30 minutes, coolit as described above and reweigh. If necessary, repeat this procedure until two successive weighings differ bynot more than 1 mg.Evaluation shall be carried out using the last

21、 mass obtained.Page 3DIN 51719 : 1997-078 EvaluationThe ash content, A(an), of the sample, expressed as a percentage by mass, is given by the following equation:m3 m1A(an) = 100 (1)m2 m1wherem1is the mass of the empty dish, in g;m2is the mass of the dish plus sample, in g;m3is the mass of the dish p

22、lus ash, in g.Unless otherwise specified, rounding shall be carried out as in DIN 1333.Conversion to other reference conditions shall be carried out as specified in DIN 51700.The ash content on a dry basis, A(wf), is given by the equation:100A(wf) = A(an) (2)100 W(an)whereA(wf) is the ash content ba

23、sed on the dry sample;A(an) is the ash content based on the moist sample as analysed;W(an) is the moisture content of the sample as analysed.9 Test reportThe test report shall refer to this standard and include the following details:a) identification of sample;b) ash content of the dry fuel, A(wf),

24、as a percentage by mass reported as the mean of at least two singlevalues and rounded to two decimal places.10 PrecisionFor results determined in accordance with this standard and reported as percentages by mass, the repeatabilityand reproducibility limits, determined as specified in the ISO 5725 se

25、ries of standards, are as given in thefollowing table.Table: PrecisionAsh content,Repeatability limit Reproducibility limitA(wf)Mean Meanless than 10% 0,20% (absolute) 0,30% (absolute) 10% or more 2,00% (relative) 3,00% (relative)Bibliography1 Ruhrkohlenhandbuch Anhaltszahlen, Erfahrungswerte und praktische Hinweise fr industrielle Verbraucher(Ruhrkohle Manual: Guideline figures, empirical values and practical information for industrial users),Essen: Verlag Glckauf GmbH.