1、Designation: E778 15Standard Test Methods forNitrogen in Refuse-Derived Fuel Analysis Samples1This standard is issued under the fixed designation E778; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 solid formsof refuse-derived fuel (R
3、DF). The procedures measure freeammonia or ammonia formed from the conversion of organicnitrogenous compounds such as amino acids and proteins.However, the procedures may not convert the nitrogenouscompounds of some wastes to ammonia. Examples of suchcompounds that may not be measured are nitro comp
4、ounds,hydrozones, oxines, nitrates, semicarbazones, pyridines, andsome 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 data from these test methods are to
5、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 The values stated in SI units are to be regarded asstandard. No other units of measurement are incl
6、uded in thisstandard.1.6 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 practices and determine the applica-bility of regulatory limitations prior t
7、o use. For specificprecautionary statements see 8.4.1 and Section 9.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD5681 Terminology for Waste and Waste ManagementE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Sp
8、e-cialty Chemicals (Withdrawn 2009)3E200 Practice for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical AnalysisE790 Test Method for Residual Moisture in a Refuse-Derived Fuel Analysis SampleE791 Test Method for Calculating Refuse-Derived FuelAnalysis Data from
9、As-Determined to Different BasesE829 Practice for Preparing Refuse-Derived Fuel (RDF)Laboratory Samples for Analysis (Withdrawn 2002)33. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D5681.4. Summary of Test Methods4.1 The determination of nitrogen is made by
10、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 bydestructive digestion of the sample with a hot, catalyzedmixture of concentrated sulfuric acid and potassium sulfate.
11、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.5. Significance and Use5.1 The standard sample is available to producers and usersof RDF as a method for determining the
12、 weight percent ofnitrogen in the analysis samples.5.2 Nitrogen 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 ammoni
13、aby this test method (see 1.1). Modifications to the digestion of1These test methods are under the jurisdiction of ASTM Committee D34 onWaste Management and are the direct responsibility of Subcommittee D34.03 onTreatment, Recovery and Reuse.Current edition approved Sept. 1, 2015. Published Septembe
14、r 2015. Originallyapproved in 1981. Last previous edition approved in 2008 as E778 08. DOI:10.1520/E077815.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the stand
15、ards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1the waste may enhance the conversion of these nitrogenou
16、scompounds to the ammonium salts.47. Apparatus7.1 Digestion UnitAn electrical heater of approximately500-W minimum rating, microwave digester, or a gas burner ofcomparable capacity. These digestion units shall be providedwith adequate means of control to maintain digestion rates asdescribed in 11.1
17、(Note 1). Commercially made, multiple-unitdigestion racks provided with 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 specified rates of digestion and distillation.7.
18、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-cooled glass or block tin condensers may beus
19、ed.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 Bulb, cylindrical type, 45 mm indiameter by
20、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. Reagents8.1 Purity of ReagentsReagent grade chemic
21、als 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 beused, provided it is first ascertained
22、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 D1193, prepared by the passagethrough an
23、 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 follows:(1) Five grams of a mixture contain
24、ing 32 parts by weightof K2SO4, 5 parts by weight of mercuric sulfate (HgSO4), and1 part by weight of selenium.(2) Three-tenths gram of mercuric selenite (HgSeO3) with7to10gofK2SO4.(3) Three-tenths gram of cupric selenite dihydrate(CuSeO22H2O)with7to10gofK2SO4. When this mixture isused, the addition
25、 of a sulfide to the alkali solution is notnecessary.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 acid(H2SO4).8.6 Potassium Permanganate (KMnO
26、4), 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 substituted forthe above, if desired (Note 2
27、 (3).8.9 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-Gunning Test Method:4Kolthoff, I. M., and Stenger
28、, 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 reagents not listed bythe American Chemical Society, see “Analar Standards fo
29、r 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 Kjeldahl Distillation ApparatusE778 1528.11.1 Methyl Red Indicator Solution
30、 (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)Prepare and standardize a 0.1 to 0.2 N sodium hydr
31、oxide(NaOH) solution against a primary standard, as described inPractice E200.8.11.3 Sulfuric Acid, Standard Solution (0.2 N)Prepareand standardize a 0.2 N sulfuric acid (H2SO4) solution asdescribed in Practice E200.8.12 Reagents Required Only for Acid-Titration TestMethod:8.12.1 Boric Acid Solution
32、 (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 methyl alcohol. Prepare fresh solutionat bimonthly int
33、ervals.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 E200, may be substituted.9. Precautions9.1 Due to the origins of RDF in municipal waste, precau
34、-tions should be observed when conducting tests on thesamples. Recommended safety practices include use of suitablegloves when handling RDF; wearing dust masks (NIOSH-approved type), especially while milling RDF samples; con-ducting tests under a negative pressure hood when possible;and washing hand
35、s upon completion of activity and beforeeating 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 RDF products are frequently inhomogene
36、ous. For thisreason significant care should be exercised to obtain a repre-sentative sample from the RDF lot to be characterized.10.2 The sampling method for this procedure should bebased on agreement between the involved parties.10.3 The sample must be air-dried and particle size reducedto pass thr
37、ough a 0.5-mm screen as described in Practice E829.This procedure must be performed carefully to preserve thesamples representativeness beyond particle size, while prepar-ing the analysis sample to be analyzed according to theseprocedures.11. Procedure for Kjeldahl-Gunning Test Method11.1 Digestion
38、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 800-mLKjeldahl flask containing 7 to 10 g of K2SO
39、4and 0.6 to 0.8 gof mercury (see Note 2).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 several times to ensure thoroughmixing and wetting o
40、f the sample.11.1.4 Incline the flask at an angle of 45 to 60C 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 foamingceases.NOTE 3When fume exhaust ducts or hood
41、s 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 flask (see Note 4).Continue the digestion until all
42、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 hascooled, a few crystals of KMnO4may be added to ensur
43、ecomplete 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 dilution by cooling the flaskunder running water
44、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 condenser, using a short piece of rubber tubing
45、 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 (two or three small pieces, if mossy zincis used),
46、 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 60Cand pouring the alkali solution slowly down the neck of theflask. Failure to maintain discrete layers during the operationmay lea
47、d to a fairly fast exothermic reaction and loss ofammonia.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 loss of ammonia willbe experienced.11.2.7 Bring th
48、e 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 Erlen-meyer flask.E778 15311.2.8 Continue the distillation at a maximum rate ofapproximately 350 mL/h until 100 to 150 mL of distillate havebee
49、n 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.11.2.10 Titrate the excess acid in the Erlenmeyer flask to amethyl red or bromcresol green end point, using 0.1 to 0.2 NNaOH solution as the titrant.11.3 Blank DeterminationRun a blank determination inthe same manner as described in 11.1 and 11.2, using approxi-mately1gofsucrose (weighed to the nearest 1 mg) as thesample material (see Note 5).NOTE 5A blank de
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