1、Designation: D 7582 09Standard Test Methods forProximate Analysis of Coal and Coke by MacroThermogravimetric Analysis1This standard is issued under the fixed designation D 7582; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These instrumental test methods cover the determinationof moisture, volatile matter, and ash, and the calculati
3、on offixed carbon in the analysis of coal and coke samples preparedin accordance with Practice D2013 and Practice D346.1.2 These instrumental test methods are not applicable tothermogravimetric analyzers using microgram size samples.1.3 The values stated in SI units are to be regarded asstandard. No
4、 other units of measurement are included in thisstandard.1.4 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-bili
5、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD2013 Practice for Preparing Coal Samples for AnalysisD3173 Test Method for Moisture in the Analysi
6、s Sample ofCoal and CokeD3174 Test Method for Ash in the Analysis Sample of Coaland Coke from CoalD3175 Test Method for Volatile Matter in the AnalysisSample of Coal and CokeD3176 Practice for Ultimate Analysis of Coal and CokeD3180 Practice for Calculating Coal and Coke Analysesfrom As-Determined t
7、o Different BasesD3302 Test Method for Total Moisture in CoalD5016 Test Method for Total Sulfur in Coal and CokeCombustion Residues Using a High-Temperature TubeFurnace Combustion Method with Infrared AbsorptionE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test
8、 Method3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D121.4. Summary of Test Method4.1 In thermogravimetric analysis the mass of a sample in acontrolled atmosphere is recorded repeatedly as a function oftemperature or time, or both. In macro thermogravimetr
9、icanalysis a sample size of approximately 1 g is used. All massmeasurements are conducted by the system. In a typicalanalysis, the temperature is normally ramped from ambient toa specific temperature and held at that temperature for aprescribed length of time. The mass change is recordedrepeatedly d
10、uring the entire procedure. For the thermogravi-metric analysis of coal and coke samples the moisture and ashanalyses are complete when the sample reaches a constantmass as defined in the instrumental operating parameters.Alternatively, the measurement of moisture and ash can beconsidered complete a
11、fter heating the sample for a fixed periodof time. In the volatile matter analysis, the samples are weighedafter heating to 950C and held at this temperature for 7 min.4.2 Moisture is determined by measuring the loss in mass ofthe analysis specimen of coal or coke when heated underspecified conditio
12、ns of temperature, time, atmosphere, speci-men mass, and equipment specifications.4.3 Volatile matter is determined by measuring the loss inmass of the analysis specimen of coal or coke when heatedunder rigidly controlled conditions. The measured mass loss isused to calculate the volatile matter aft
13、er correcting for themoisture content.4.4 Ash is determined by measuring the mass of the residueremaining after burning the coal or coke specimen underspecified conditions of specimen mass, temperature, time,atmosphere, and equipment specifications.4.5 In these test methods, moisture, volatile matte
14、r, and ashcan be determined sequentially in a single instrumental proce-dure. Another procedure allows the moisture and ash to bedetermined sequentially. Moisture and ash can also be deter-mined in separate determinations. Ruggedness testing and past1This test method is under the jurisdiction of AST
15、M Committee D05 on Coaland Coke and is the direct responsibility of Subcommittee D05.21 on Methods ofAnalysis.Current edition approved Nov. 1, 2009. Published November 2009.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
16、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.experiences have shown the volatile matter values determinedon samples wi
17、thout first determining the moisture (drying thesample) are always higher than those of the dried samples.4.6 Where a relative bias between these test methods andother ASTM test methods for the proximate analysis of coaland coke has been shown to exist (16.2), the instrument used inthese test method
18、s must be calibrated using specimens ofknown composition covering the range of parameters beingdetermined.5. Significance and Use5.1 Moisture, as determined by this instrumental testmethod, is used for calculating other analytical results to a drybasis using procedures in Practice D3180.5.2 Moisture
19、 can be used in conjunction with the air-drymoisture loss determined by Test Method D3302 to determinetotal moisture in coal. Total moisture is used for calculatingother analytical results to an as-received basis using PracticeD3180.5.3 Ash yield is the residue remaining after heating the coaland co
20、ke samples (see Note 1).NOTE 1The ash obtained differs in composition and amount from themineral constituents present in the original coal. Combustion causes anexpulsion of all water, the loss of carbon dioxide from carbonates, theconversion of iron pyrite into iron oxides and sulfur oxides, and oth
21、erchemical reactions. Ash yield, as determined by this test method, candiffer from the amount of ash produced in furnace operations or othercombustion systems because combustion conditions influence the chem-istry and amount of ash.5.4 Ash yield is used, (1) as a parameter for evaluatingsampling pro
22、cedures and coal cleaning processes, (2) in theultimate analysis calculation of oxygen by difference usingPractice D3176, (3) in calculations including material balance,reactivity and yields of products relevant to coal conversionprocesses such as gasification and liquefaction, (4) in calcula-tions
23、to estimate the loading on electrostatic precipitators andon the fly ash and bottom ash disposal systems as well aserosion rates on boiler systems.5.5 Volatile matter yield, when determined as herein de-scribed, may be used to (1) indicate coke yield on carboniza-tion, (2) provide the basis for purc
24、hasing and selling, or (3)establish combustion characteristics.5.6 Fixed carbon is a calculated value. It is the differencebetween 100 and the sum of the percent moisture, ash, andvolatile matter. All percents shall be on the same moisturereference base.5.7 Moisture, ash, and volatile matter are thr
25、ee of theprincipal parameters used for assessing the quality of coal.6. Interferences6.1 There are no known interferences for these test methods.7. Apparatus7.1 Macro Thermogravimetric Analyzer (Macro TGA)Acomputer controlled apparatus consisting of a furnace with acavity large enough to accept cruc
26、ibles containing test speci-mens that meet the minimum mass requirements of theprocedure. The macro TGA system can accommodate multiplecrucibles, allowing for continuous analysis with one cruciblereserved for the blank or reference crucible. The furnace isconstructed so the cavity is surrounded by a
27、 suitable refractoryand insulated so as to develop a uniform temperature in allparts of the cavity, but with a minimum free space. The furnaceshall be capable of being heated rapidly (30-45C/min fromambient to 950C. The temperature shall be monitored andmaintained at values specified for each determ
28、ination. Thesystem shall have an integrated balance capable of weighingthe crucibles and test specimens repeatedly throughout theanalysis. All mass measurements are conducted and recordedby the system. The sensitivity of the balance shall be at least0.1 mg. Provision shall be made to introduce gases
29、 specifiedfor this standard and to remove products of drying, devolatil-ization, and combustion. The macro TGA system shall have aventing fan, tolerant of hot product gases, to efficiently removethe exhaust gases.7.2 Crucibleswith covers of composition and dimensionsspecified for the instrument by t
30、he instrument manufacturer.The covers shall fit closely enough so that the carbon depositfrom bituminous, subbituminous, and lignitic coals does notburn away from the underside of the cover during the deter-mination of the volatile matter8. Reagents and Materials8.1 Drying GasNitrogen (99.5% purity)
31、, Argon (99.5%purity) or air, dried to a moisture content of 1.9 mg/L or less(dew point 10C or less).8.2 Inert GasNitrogen (99.5% purity) or Argon (99.5%purity).8.3 Oxidizing GasOxygen (99.5% purity) or air.8.4 Reference MaterialsCoal or coke material(s) meetingthe requirements of 10.1, with a certi
32、ficate of analysis speci-fying the reference value and the uncertainty of the referencevalue. Reference material(s) can be employed to calibrate theinstrument for the determination of volatile matter. It ispreferable to employ reference materials(s) that include infor-mation on the certificate of an
33、alysis concerning method(s)employed to determine volatile matter of the reference mate-rial.9. Hazards9.1 The user shall insure acceptable documented safetyprocedures are in place for the handling of all reagents and testmaterials and for the operation of laboratory equipment speci-fied for these te
34、st methods.9.2 Venting EquipmentInstall equipment in the vicinity ofthe apparatus to vent combustion and volatile gases evolvedduring the test procedures from the laboratory.10. Analysis Sample10.1 The analysis sample shall be the material pulverized topass a 250-m (No. 60) sieve in accordance with
35、PracticeD2013 or Practice D346.11. Preparation of Apparatus11.1 Verify the instrument can meet all specifications in thestandard with respect to gas flows, heating rates, and balanceD7582092sensitivity prior to use. Condition the instrument after initialsetup, or repairs, by conducting a run through
36、 a complete cyclewithout samples.11.2 Condition new crucibles and covers for use in these testmethods by heating under the same conditions of the test andcool before use.11.3 The macro TGA system can be programmed to termi-nate the measurement process when the test specimens andcrucibles have reache
37、d a constant mass. Crucibles are weighedby the instrument at specified intervals. The analysis iscomplete when the sample reaches constant mass. Constantmass is defined as a point where the mass change is or = to0.05% over a nine-minute period, either by using not less thanthree successive weighings
38、 or a fixed nine-minute period ofsuccessive weighings. This mass change of 0.05% is equivalentto 0.0005 g for a 1.0000 g sample. Alternately, the instrumentcan be programmed to allow for moisture and ash determina-tion by heating the test specimens for the time periods, heatingrates and soak tempera
39、tures specified in Test Methods D3173and D3174. The mass measured at the end of the time periodis used for calculations.12. Calibration and Standardization12.1 The instrument can be calibrated for the determinationof volatile matter employing reference materials. The calibra-tion must be performed a
40、t the same furnace ramp temperatureas that used for the analysis. Do not use coal referencematerials(s) for coke volatile matter calibration. Do not usecoke reference material(s) for coal volatile matter calibration.Use coal reference material(s) with a reference value anduncertainty based on measur
41、ements made employing D3175 tocalibrate this test method for the purpose of determining coalrank.13. Procedure13.1 The determination of moisture, followed by volatilematter followed by ash can be carried out in sequence using thesame test specimen. Alternatively, the determination of mois-ture, vola
42、tile matter, or ash can be carried out separately on testspecimens of coal or coke.13.2 Sequential Determination of Moisture, Volatile Matterand Ash:13.2.1 After verifying instrument setup according to Section11 on the preparation of apparatus, load and tare the crucibles.Add1g6 0.1 g of coal or cok
43、e to the crucible in the balanceposition and weigh immediately before advancing the nextcrucible. Transfer the test specimen from the sample bottle tothe crucible quickly to minimize the exposure of the testspecimen to the atmosphere during the initial weighing pro-cess.13.2.2 For moisture determina
44、tions, heat the weighed testspecimens in crucibles without the covers at 107 6 3 C. Usea drying gas flow rate of 0.4 to 1.4 furnace volume changes perminute (see 8.1). Program the instrument to terminate the testwhen the test specimens and crucibles have reached a constantmass (see 11.3). Alternativ
45、ely, program the instrument to allowfor moisture determination by heating the test specimens for 1h.13.2.3 For volatile matter determinations following themoisture analysis, place covers on the crucibles in the TGAcarousel (the crucibles are placed automatically in somesystems and manually in others
46、). Program the instrument toreweigh the crucibles, with specimens inside, and covers inplace before initiating the volatile matter part of the cycle.13.2.3.1 To provide an inert atmosphere, use nitrogen orargon with a flow rate of 0.7 to 1.4 furnace volume changes perminute to sweep away the volatil
47、e components. Raise thefurnace temperature at a rate such that the temperature is raisedfrom 107C to 950 6 10C in a 26-30 min time period (SeeNote 2). Program the instrument to hold at this temperature for7 min. The TGA weighs the covered crucibles at regularintervals while the temperature of the fu
48、rnace is raised. Theweights of the crucibles and covers at the end of the 7-min holdperiod are used in the calculation of the volatile matter.NOTE 2It is the nature of resistance furnaces to start heating slowlywith a gradual increase in heating rate until the furnace heating elementcontroller reduc
49、es the power to moderate the heating rate.As a result, highfurnace ramp rates are seldom ever uniform over the temperature rangeselected. Selecting a heating time (26-30 min) with a high heating ramprate accomplishes the desired result, to duplicate the conditions (MacroTGA furnaces set at 30-45C/min ramp rate) that were used by thelaboratories in the interlaboratory study. At the same time, it allows theMacro TGA furnaces to moderate the heating rate enough to avoidovershooting the selected high temperature of 950C.13.2.3.2 With strongly caking low-volatile and med
