1、Designation: E 790 87 (Reapproved 2004)Standard Test Method forResidual Moisture in a Refuse-Derived Fuel AnalysisSample1This standard is issued under the fixed designation E 790; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of the residualmoisture in an analysis sample of RDF. It is used to
3、calculateto the dry basis other determinations performed on the analysissample. It is used with the air-dry moisture results to calculatetotal moisture (Note 1). The total moisture is used to calculateas-received values or other analyses performed on the sample.NOTE 1In some instances RDF moisture m
4、ay change during thesize-reduction steps of the analysis sample preparation procedure. Thismoisture change, unless suitable corrections are made, will affect theaccuracy of the total moisture value as calculated from the air-dry andresidual moisture results.1.2 The values stated in acceptable metric
5、 units are to beregarded as standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health pra
6、ctices and determine the applica-bility of regulatory limitations prior to use. For more specificprecautionary information see Section 7.2. Referenced Documents2.1 ASTM Standards:2D 3173 Test Method for Moisture in theAnalysis Sample ofCoal and CokeE 180 Practice for Developing Precision of ASTM Met
7、hodsfor Analysis and Testing of Industrial Chemicals3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 air dryinga process of partial drying of RDF tobring its moisture content near to equilibrium with the atmo-sphere in which further reduction, division, and characteriza-tion of
8、 the sample are to take place. In order to bring about theequilibrium, the RDF is usually subjected to drying undercontrolled temperature conditions ranging from 30 to 40C.3.1.2 analysis samplethe final subsample prepared fromthe air-dried laboratory sample but reduced by passing througha mill with
9、a 0.5-mm (0.02-in.) size or smaller final screen.3.1.3 biasa systematic error that is consistently negativeor consistently positive. The mean of errors resulting from aseries of observations that does not tend towards zero.3.1.4 gross samplea sample representing one lot andcomposed of a number of in
10、crements on which neither reduc-tion nor division has been performed.3.1.5 laboratory samplea representative portion of thegross sample received by the laboratory for analysis.3.1.6 lota large designated quantity (greater than thequantity of the final sample) of RDF which can be representedby a prop
11、erly selected gross sample.3.1.7 precisiona term used to indicate the capability of aperson, an instrument, or a method to obtain reproducibleresults; specifically, a measure of the random error as ex-pressed by the variance, the standard error, or a multiple of thestandard error.3.1.8 refuse-derive
12、d fuelssolid forms of refuse-derivedfuels from which appropriate analytical samples may beprepared are defined as follows in ASTM STP 832.3RDF-1Wastes used as a fuel in as-discarded form withonly bulky wastes removed.RDF-2Wastes processed to coarse particle size with orwithout ferrous metal separati
13、on.RDF-3Combustible waste fraction processed to particlesizes, 95 % passing 2-in. square screening.RDF-4Combustible waste fraction processed into powderform, 95 % passing 10-mesh screening.RDF-5Combustible waste fraction densified (compressed)into the form of pellets, slugs, cubettes, or briquettes.
14、3.1.9 representative samplea sample collected in such amanner that it has characteristics equivalent to the lot sample.1This test method is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommittee D34.03.02 onMunicipal Recovery and Reuse.Curren
15、t edition approved Aug. 28, 1987. Published October 1987. Orginallypublished as E 790 81. Last previous edition E 790 81.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refe
16、r to the standards Document Summary page onthe ASTM website.3Thesaurus on Resource Recovery Terminology, ASTM STP 832, ASTM, 1983,p. 72.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.10 sample divisionthe process of extracting a
17、 smallersample from a sample so that the representative properties ofthe larger sample are retained. During this process it is assumedthat no change in particle size or other characteristics occurs.3.1.11 sample preparationthe process that includes dry-ing, size reduction, division, and mixing of a
18、laboratory samplefor the purpose of obtaining an unbiased analysis sample.3.1.12 sample reductionthe process whereby sample par-ticle size is reduced without change in sample weight.3.1.13 significant lossany loss that introduces a bias infinal results that is of appreciable importance to concernedp
19、arties.4. Summary of Test Method4.1 This test method is based on the loss in weight of anair-dried analysis sample of RDF under rigidly controlledconditions of temperature, time, and air flow.4.2 The total moisture is calculated from the loss or gain inair drying and the residual moisture as determi
20、ned by this testmethod.5. Significance and Use5.1 The treatment of the sample as specified herein isintended for the purpose of determining the residual moisturepresent in an analysis sample of RDF.5.2 The residual moisture value is used to convert as-determined analyses such as gross heating value,
21、 sulfur, andash to a dry sample basis.6. Apparatus6.1 Drying Oven:6.1.1 Referee TypeThe oven shall be so constructed as tohave a uniform temperature within the specimen chamber, havea minimum excess air volume, and be capable of constanttemperature regulation at 107 6 3C. Provision shall be madefor
22、renewing the preheated air in the oven at the rate of two tofour times a minute, with the intake air dried by passing itthrough a desiccant. An oven similar to the one illustrated inFig. 1 of Test Method D 3173 is suitable.6.1.2 Routine TypeAdrying oven of either the mechanicalor natural circulation
23、 type which is capable of constant uniformtemperature within the specimen chamber regulated at 107 63C.NOTE 2Either type of oven may be used for routine determinations.However, the referee-type oven shall be used to resolve differencesbetween determinations.6.2 ContainersA convenient form that allow
24、s the ashdetermination to be made on the same sample is a porcelaincapsule 22 mm in depth and 44 mm in diameter or a fusedsilica capsule of similar shape. This shall be used with awell-fitting flat aluminum cover. Platinum crucibles or glasscapsules with ground-glass caps may also be used. They shou
25、ldbe as shallow as possible consistent with convenient handle-ability.6.3 Analytical Balance, with 0.1 mg sensitivity.6.4 Analysis Sample ContainersHeavy (minimum 4 mil),vapor-impervious bags, properly sealed; or noncorroding cans,glass jars, or plastic bottles with air-tight sealing covers to store
26、RDF samples for analysis. Containers shall be checked forsuitability by measuring weight loss or gain of the sample andcontainer stored for 1 week under ambient laboratory condi-tions. The weight loss or gain should be less than 0.5 % of thesample weight stored in the container.7. Precautions7.1 Due
27、 to the origins of RDF in municipal waste, commonsense dictates that some precautions should be observed whenconducting tests on the samples. Recommended hygienicpractices include use of gloves when handling RDF; wearingdust masks (NIOSH-approved type), especially when shred-ding RDF samples; conduc
28、ting tests under negative pressurehood when possible; and washing hands before eating orsmoking.7.2 Laboratory sample handling shall be performed bytrained personnel. All operations shall be done rapidly aspossible to avoid sample moisture changes due to atmosphericexposure.7.3 Since heavy fine part
29、icles tend to segregate rapidly inthe RDF analysis sample, the analyst should exercise care toassure that the analysis sample is well-mixed prior to perform-ing this determination.7.4 When the residual moisture is to be used for thedetermination of total moisture, special care shall be taken toavoid
30、 any change in sample moisture between the completionof air drying and analysis for residual moisture. It is recom-mended that the delay between sample preparation and thedetermination of residual moisture be a maximum of 72 h.8. Sampling48.1 RDF products are frequently nonhomogeneous. For thisreaso
31、n, significant care should be exercised to obtain a repre-sentative laboratory sample from the RDF lot to be character-ized.8.2 The sample method for this procedure should be basedon agreement between the involved parties.8.3 The laboratory sample must be air-dried and particlesize reduced to pass a
32、 0.5-mm screen for this analysis. Thisprocedure must be performed carefully to preserve the sam-ples representative characteristics (other than particle size)while preparing the analysis sample to be used in this proce-dure.9. Procedure9.1 Heat the empty containers and covers under the condi-tions a
33、t which the sample is to be dried, place the stopper orcover on the container, cool over a desiccant for about 15 to 20min, and weigh. Mix the sample, if necessary, and dip out witha spoon or spatula from the sample bottle approximately1gofthe sample. Put the sample quickly into the container, cover
34、,and weigh at once.NOTE 3If weighing bottles with air-tight covers are used, it may not4ASTM Subcommittee E38.01 is currently in the process of developingprocedures for sampling RDF and the preparation of an analysis sample. Thechairman of E38.01 should be contacted for details.E 790 87 (2004)2be ne
35、cessary to preheat the moisture analysis container nor to desiccate itafter drying.9.2 Remove the cover and place in a desiccator. Quicklyplace the uncovered container into an oven preheated to 107 63C through which is passed a current of dry air. Close theoven at once and heat for 1 hr. Open the ov
36、en, remove, coverthe container quickly, and cool in a desiccator over desiccant.Weigh the sample and container as soon as cooled toroom temperature.10. Calculation (see Note 1)10.1 Calculate the percent residual moisture, R,intheanalysis sample as follows:R 5S 2 BS3 100 (1)where:S = grams of analysi
37、s sample used, andB = grams of sample after heating.10.2 Calculate the percent total moisture in the laboratorysample, as follows:M 5R 100 2 A!1001 A (2)where:R = residual moisture, %, andA = air dry loss determined during preparation of theanalysis sample, %.10.3 To convert other parameters determi
38、ned on the analysissample, such as ash, sulfur, and gross calorific value, to a drysample basis, the following equation can be used:Pdry5Pad100!100 2 R(3)where:Pad= parameter, %“ as-determined” on the analysissample,R = residual moisture, % (see 10.1), andPdry= parameter, % expressed on a dry sample
39、 basis.11. Precision and Bias11.1 Precision:11.1.1 The standard deviations of individual determinations,in percent absolute are as follows:Typical AverageValueWithinLaboratoriesBetweenLaboratories2.54.5 % 0.15 % 0.50 %11.1.2 The above precision estimates are based on aninterlaboratory study conducte
40、d in accordance with PracticeE 180.11.2 BiasThe bias of this test method has not beendetermined due to a lack of a recognized standard referencematerial.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. U
41、sers of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed eve
42、ry five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible techn
43、ical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E 790 87 (2004)3
