ASTM E778-2008 431 Standard Test Methods for Nitrogen in the Analysis Sample of Refuse-Derived Fuel《回收废燃料的分析样品中氮的标准试验方法》.pdf

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1、Designation: E 778 08Standard 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 year of last revisi

2、on. A number 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

3、 fuel (RDF). 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 ni

4、tro compounds,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

5、 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 The values stated in SI units are to be regarded asstandard. No other units of measurement

6、are included 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

7、 prior to use. For specificprecautionary statements see 8.4.1 and Section 9.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 5681 Terminology for Waste and Waste ManagementE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Indust

8、rial and Spe-cialty ChemicalsE 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysisE 790 Test Method for Residual Moisture in a Refuse-Derived Fuel Analysis SampleE 791 Test Method for Calculating Refuse-Derived FuelAnalysis Data from As-

9、Determined to Different BasesE 829 Practice for Preparing Refuse-Derived Fuel (RDF)Laboratory Samples for Analysis33. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D 5681.4. Summary of Test Methods4.1 The determination of nitrogen is made by either theKjeldahl

10、-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.The salts are subs

11、equently 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 weight percent of

12、nitrogen in the analysis sample.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 ammoniaby this test metho

13、d (see 1.1). Modifications to the digestion ofthe waste may enhance the conversion of these nitrogenouscompounds to the ammonium salts.41These test methods are under the jurisdiction of ASTM Committee D34 onWaste Management and are the direct responsibility of Subcommittee D34.03.02 onMunicipal Reco

14、very and Reuse.Current edition approved Sept. 1, 2008. Published October 2008. Originallyapproved in 1981. Last previous edition approved in 2004 as E 778 87(2004).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Boo

15、k of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Kolthoff, I. M., and Stenger, V. A., Volumetric Analysis II, IntersciencesPublishers, Inc., New York,

16、 NY, pp. 173176.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. 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 wi

17、th adequate means ofcontrol to maintain 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, m

18、ay be needed tomaintain the specified 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 distilla

19、tion racks pro-vided with water-cooled 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

20、 purpose.7.5 Kjeldahl Connecting Bulb, 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

21、 Pure Gum Rubber Tubing.8. Reagents8.1 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 specificati

22、ons are available.5Other grades may 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,

23、 Type II,conforming to Specification 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

24、K2SO4required in their use, are as follows:(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 di

25、hydrate (CuSeO22H2O)with7to10gofK2SO4. 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

26、(sp gr 1.84)Concentrated sulfuric acid(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

27、 potassium hydroxide (KOH) may be substituted forthe above, if desired (Note 2 (c).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 R

28、eagents Required for Kjeldahl-Gunning 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 Hydrox

29、ide, Standard Solution (0.1 to 0.2N)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

30、200.8.12 Reagents Required Only for Acid-Titration TestMethod: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 for Laboratory U.K.Chemicals,

31、” 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 ApparatusE7780828.12.1 Boric Acid Solution (50 g/L) Dissolve5gofboricacid (H3BO3

32、) 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 intervals.8.12.3 Sulfuric Acid, Standard

33、 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 Due to the origins of RDF in municipal waste, commonsense dictates that precautions shou

34、ld 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 tests under a negative pressure hoodwhen possible; and washing hands before eating or sm

35、oking.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 nonhomogeneous. Forthis reason significant care should be exer

36、cised 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 sample must be air-dried and particlesize reduced to pass a 0.5-mm screen as described in Pra

37、cticeE 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. Procedure for Kjeldahl-Gunning Test Method11.1 Digestion of Sample.11.1.1 After thoroughly mixing

38、 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 K2SO4and 0.6 to 0.8 gof mercury (see Note 2)

39、.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 of the sample.11.1.4 Incline the flask at

40、 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 hoods are not available anothermethod must b

41、e 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 sample particles are oxidized,as evidenc

42、ed 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 ensurecomplete oxidation; further heating may

43、 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 or by allowing it to stand until cool.11

44、.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 as a seal.11.2.4 Incline the Erlenmeyer

45、 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), and slowly add 100 mL of alkali solutio

46、n 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 lead to a fairly fast exothermic reaction a

47、nd 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 the contents of the Kjeldahl flask to a bo

48、ilcarefully 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

49、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).E778083NOTE 5A blank determination must be made with every series o