1、Designation: E 778 87 (Reapproved 2004)Standard Test Methods forNitrogen in the Analysis Sample of Refuse-Derived Fuel1This standard is issued under the fixed designation E 778; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 These test methods cover the determination of totalKjeldahl nitrogen in (prepared analysis) samples of (solidf
3、orms) of refuse-derived fuel (RDF). The procedures measurefree ammonia or ammonia formed from the conversion oforganic nitrogenous compounds such as amino acids andproteins. However, the procedures may not convert the nitrog-enous compounds of some wastes to ammonia. Examples ofsuch compounds that m
4、ay not be measured are nitro com-pounds, hydrozones, oxines, nitrates, semicarbazones, py-ridines, and some refractory tertiary amines.1.2 Two alternatives are described for the final determina-tion of the ammonia, the Kjeldahl-Gunning Test Method andthe Acid-Titration Test Method.1.3 The analytical
5、 data from these test methods are to bereported as part of the ultimate analysis where ultimate analysisis requested.1.4 These test methods may be applicable to any wastematerial from which a laboratory analysis sample can beprepared.1.5 This standard does not purport to address all of thesafety con
6、cerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary statements see 8.4.1 and Section 9.2. Referenced Docum
7、ents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial ChemicalsE 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysisE 790 Test Met
8、hod for Residual Moisture in Refuse-Derived Fuel Analysis SampleE 791 Test Method for Calculating Refuse-Derived FuelAnalysis Data from As-Determined to Different BasesE 829 Practice for Preparing Refuse-Derived Fuel (RDF)Laboratory Samples for Analysis3. Terminology3.1 Definitions of Terms Specific
9、 to This Standard:3.1.1 refuse-derived fuelsolid 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 w
10、ith orwithout ferrous metal separation.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 pell
11、ets, slugs, cubettes, or briquettes.4. Summary of Test Methods4.1 The determination of nitrogen is made by either theKjeldahl-Gunning Test Method (Section 11) or the Acid-Titration Test Method (Section 12). In both these methods thenitrogen in the sample is converted into ammonium salts bydestructiv
12、e digestion of the sample with a hot, catalyzedmixture of concentrated sulfuric acid and potassium sulfate.The salts are subsequently decomposed in a hot alkalinesolution from which the ammonia is recovered by distillation,and finally determined by alkalimetric or acidimetric titration.1These test m
13、ethods are under the jurisdiction of ASTM Committee D34 onWaste Management and are the direct responsibility of Subcommittee D34.03.02 onMunicipal Recovery and Reuse.Current edition approved Aug. 28, 1987. Published October 1987. Originallypublished as E 778 81. Last previous edition E 778 81.2For r
14、eferenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Thesaurus on Resource Recovery Terminology, ASTM STP 832, ASTM, 19
15、83,p. 72.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 The standard sample is available to producers and usersof RDF as a method for determining the weight percent ofnitrogen in the analysis sample.5.2 Ni
16、trogen is part of the ultimate analysis and can be usedfor calculation of combustion parameters.6. Interferences and Limitations6.1 Because of the nature of RDF, nitrogenous compoundsmay be present which will not readily be converted to ammoniaby this test method (1.1). Modifications to the digestio
17、n of thewaste may enhance the conversion of these nitrogenous com-pounds to the ammonium salts.47. Apparatus7.1 Digestion UnitAn electrical heater of approximately500-W minimum rating or a gas burner of comparable capacity.Either type of heater shall be provided with adequate means ofcontrol to main
18、tain digestion rates as described in 11.1 (Note1). Commercially made, multiple-unit digestion racks providedwith fume exhaust ducts may be used.NOTE 1If commercially made electrical heaters are used, auxiliaryvoltage control equipment, such as an autotransformer, may be needed tomaintain the specifi
19、ed rates of digestion and distillation.7.2 Distillation Unit (Fig. 1)An electrical heater or gasburner as described in 7.1. Either type shall be provided withadequate means of control to maintain rates as described in11.2. Commercially made, multiple-unit distillation racks pro-vided with water-cool
20、ed glass or block tin condensers may beused.7.3 Condenser, glass, water-cooled, having a minimumjacket length of 500 mm.7.4 Kjeldahl Digestion Flask, of heat-resistant glass, havinga capacity of 500 or 800 mL. Borosilicate glass has been foundsatisfactory for this purpose.7.5 Kjeldahl Connecting Bul
21、b, cylindrical type, 45 mm indiameter by 100 mm long, or larger, with curved inlet andoutlet tubes.7.6 Receiving FlasksErlenmeyer flask having a capacityof 250 or 300 mL.7.7 Connecting TubeGlass tubing approximately 10 mmin outside diameter by 200 mm in length.7.8 Pure Gum Rubber Tubing.8. Reagents8
22、.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may
23、beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water, Type II,conforming to Specification
24、 D 1193, prepared by the passagethrough an ion-exchange column containing a strongly acidcation resin in the hydrogen form.8.3 Potassium Sulfate (K2SO4), crystals.NOTE 2Other satisfactory and permissible catalysts for the digestion,together with the quantities of K2SO4required in their use, are as f
25、ollows:(1) Five grams of a mixture containing 32 parts by weight of K2SO4,5parts by weight of mercuric sulfate (HgSO4), and 1 part by weight ofselenium.(2) Three-tenths gram of mercuric selenite (HgSeO3)with7to10gofK2SO4.(3) Three-tenths gram of cupric selenite dihydrate (CuSeO22H2O)with7to10gofK2SO
26、4. When this mixture is used, the addition of asulfide to the alkali solution is not necessary.8.4 Mercury, metal (see Note 2).8.4.1 WarningAppropriate safety precautions should beused when handling and disposing of mercury and seleniumcompounds.8.5 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric ac
27、id(H2SO4).8.6 Potassium Permanganate (KMnO4), crystals.8.7 Zinc, mossy or granular.8.8 Alkali SolutionDissolve 8.0 g of potassium sulfide(K2S) and 500 g of sodium hydroxide (NaOH) in water anddilute to 1 L. The use of appropriate amounts of sodium sulfide(Na2S) or potassium hydroxide (KOH) may be su
28、bstituted forthe above, if desired (Note 2 (c).4Kolthoff, I. M., and Stenger, V. A., Volumetric Analysis II, IntersciencesPublishers, Inc., New York, NY, pp. 173176.5“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal Soc., Washington, DC. For suggestions on the testing of r
29、eagents not listed bythe American Chemical Society, see “Analar Standards for Laboratory U.K.Chemicals,” BDH Ltd., Poole, Dorset, and the “United States Pharmacopoeia”.A = electric heaterB = Kjeldahl digestion flaskC = Kjeldahl connecting bulbD = condenserE = connecting tubeF = receiving flaskFIG. 1
30、 Kjeldahl Distillation ApparatusE 778 87 (2004)28.9 Ethyl Alcohol (95 %)Ethyl alcohol conforming toFormula No. 30 or 2A of the U.S. Bureau of Internal Revenue.Methyl alcohol may be substituted.8.10 SucroseNational Bureau of Standards primary stan-dard grade.8.11 Reagents Required for Kjeldahl-Gunnin
31、g Test Method:8.11.1 Methyl Red Indicator Solution (0.4 to 1 g/L)Dissolve 0.04 to 0.1 g of methyl red in 50 mL of 95 % ethylalcohol or methyl alcohol and add 50 mL of water. Bromcresolgreen indicator solution of equal concentration may be used.8.11.2 Sodium Hydroxide, Standard Solution (0.1 to 0.2N)
32、Prepare and standardize a 0.1 to 0.2 N sodium hydroxide(NaOH) solution against a primary standard, as described inPractice E 200.8.11.3 Sulfuric Acid, Standard Solution (0.2 N)Prepareand standardize a 0.2 N sulfuric acid (H2SO4) solution asdescribed in Practice E 200.8.12 Reagents Required Only for
33、Acid-Titration TestMethod:8.12.1 Boric Acid Solution (50 g/L)Dissolve5gofboricacid (H3BO3) in 100 mL of boiling water. Allow to cool toroom temperature before use.8.12.2 Mixed Indicator SolutionPrepare a solution con-taining 0.125 % methyl red and 0.083 % methylene blue in95 % ethyl alcohol or in me
34、thyl alcohol. Prepare fresh solutionat bimonthly intervals.8.12.3 Sulfuric Acid, Standard Solution (0.1 to 0.2 N)Prepare and standardize a 0.1 to 0.2 N sulfuric acid (H2SO4)solution. Hydrochloric acid (HCl) of similar concentration, asdescribed in Practice E 200, may be substituted.9. Precautions9.1
35、 Due to the origins of RDF in municipal waste, commonsense dictates that precautions should be observed whenconducting tests on the samples. Recommended hygienicpractices include use of gloves when handling RDF; wearingdust masks (NIOSH-approved type), especially while millingRDF samples; conducting
36、 tests under a negative pressure hoodwhen possible; and washing hands before eating or smoking.9.2 The hot acidic and basic solutions in this procedure posea significant potential hazard. Proper laboratory safety prac-tices and equipment should be employed throughout thisprocedure.10. Sampling10.1 R
37、DF products are frequently nonhomogeneous. Forthis reason significant care should be exercised to obtain arepresentative laboratory sample from the RDF lot to becharacterized.10.2 The sampling method for this procedure should bebased on agreement between the involved parties.10.3 The laboratory samp
38、le must be air-dried and particlesize reduced to pass a 0.5-mm screen as described in PracticeE 829. This procedure must be performed carefully to preservethe samples representative characteristics, other than particlesize, while preparing the analysis sample to be used in theprocedures.11. Procedur
39、e for Kjeldahl-Gunning Test Method11.1 Digestion of Sample.11.1.1 After thoroughly mixing the RDF analysis sample toprovide the best possible mix of heavy fines with milled fluff,weigh approximately1gtothenearest 1 mg of sample into aweighing scoop.11.1.2 Carefully transfer the sample into a 500 or
40、800-mLKjeldahl flask containing 7 to 10 g of K2SO4and 0.6 to 0.8 gof mercury (see Note 3).11.1.3 Add 30 mL of H2SO4(sp gr 1.84) to the mixture bypouring it down the neck of the flask while rotating the flask towash any sample adhering to the walls into the mixture. Swirlthe contents of the flask sev
41、eral times to ensure thoroughmixing and wetting of the sample.11.1.4 Incline the flask at an angle of 45 to 60 on thedigestion heater in a fume hood (Note 3). Heat the contentsgradually. If frothing or foaming occurs, or both, lower the heatand digest at a lower temperature until the frothing or foa
42、mingceases.NOTE 3When fume exhaust ducts or hoods are not available anothermethod must be used to exhaust fumes from the flask, such as aspiration.11.1.5 Heat the contents to boiling, controlling the heatinput in such a manner that the H2SO4vapors condense nomore than halfway up the neck of the flas
43、k (see Note 1).Continue the digestion until all sample particles are oxidized,as evidenced by a nearly colorless solution, or for at least 2 hafter the solution has reached a straw color. The total time ofdigestion will require 3 to 6 h.11.1.6 When the digestion is completed and the solution hascool
44、ed, a few crystals of KMnO4may be added to ensurecomplete oxidation; further heating may be necesary to destroythe excess permanganate and decolorize the solution.11.2 Distillation of Digestate (see Fig. 1).11.2.1 Dilute the cooled digestion mixture to about 300 mLwith water and remove any heat of d
45、ilution by cooling the flaskunder running water or by allowing it to stand until cool.11.2.2 Accurately pipet 20.0 mL of 0.2 N H2SO4into a 250or 300-mL Erlenmeyer flask. Add 6 drops of methyl red orbromcresol green indicator solution.11.2.3 Attach the glass connecting tube to the discharge endof the
46、 condenser, using a short piece of rubber tubing as a seal.11.2.4 Incline the Erlenmeyer flask at a suitable angle andinsert this tube so that the end is immersed well below thesurface of the acid solution (see Fig. 1).11.2.5 Add 1 to2gofgranular zinc to the digestion mixturein the Kjeldahl flask (t
47、wo or three small pieces, if mossy zincis used), and slowly add 100 mL of alkali solution so that itforms a distinct layer under the acid solution. This may beaccomplished by inclining the flask at an angle of 45 to 60 andpouring the alkali solution slowly down the neck of the flask.Failure to maint
48、ain discrete layers during the operation maylead to a fairly fast exothermic reaction and loss of ammonia.11.2.6 Quickly connect the flask to the distilling condenserthrough the Kjeldahl connecting bulb and swirl the contents topromote thorough mixing.NOTE 4All connections must be air-tight so no lo
49、ss of ammonia willbe experienced.E 778 87 (2004)311.2.7 Bring the contents of the Kjeldahl flask to a boilcarefully in order to avoid bumping or foaming, or both, anddistill the ammonia over into the acid solution in the Erlenm-eyer flask.11.2.8 Continue the distillation at a maximum rate ofapproximately 350 mL/h until 100 to 150 mL of distillate havebeen collected.11.2.9 Discontinue the boiling, and remove the glass con-necting tube from the condenser and Erlenmeyer flask. Rinsethe tube with water, collecting the washings in the Erlenmeyerflask.1
