ASTM D7582-09
(Test Method)Standard Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric Analysis
Standard Test Methods for Proximate Analysis of Coal and Coke by Macro Thermogravimetric Analysis
SIGNIFICANCE AND USE
Moisture, as determined by this instrumental test method, is used for calculating other analytical results to a dry basis using procedures in Practice D3180.
Moisture can be used in conjunction with the air-dry moisture loss determined by Test Method D3302 to determine total moisture in coal. Total moisture is used for calculating other analytical results to an as-received basis using Practice D3180.
Ash yield is the residue remaining after heating the coal and coke samples (see Note 1).
Note 1—The ash obtained differs in composition and amount from the mineral constituents present in the original coal. Combustion causes an expulsion of all water, the loss of carbon dioxide from carbonates, the conversion of iron pyrite into iron oxides and sulfur oxides, and other chemical reactions. Ash yield, as determined by this test method, can differ from the amount of ash produced in furnace operations or other combustion systems because combustion conditions influence the chemistry and amount of ash.
Ash yield is used, (1) as a parameter for evaluating sampling procedures and coal cleaning processes, (2) in the ultimate analysis calculation of oxygen by difference using Practice D3176, (3) in calculations including material balance, reactivity and yields of products relevant to coal conversion processes such as gasification and liquefaction, (4) in calculations to estimate the loading on electrostatic precipitators and on the fly ash and bottom ash disposal systems as well as erosion rates on boiler systems.
Volatile matter yield, when determined as herein described, may be used to (1) indicate coke yield on carbonization, (2) provide the basis for purchasing and selling, or (3) establish combustion characteristics.
Fixed carbon is a calculated value. It is the difference between 100 and the sum of the percent moisture, ash, and volatile matter. All percents shall be on the same moisture reference base.
Moisture, ash, and volatile matter are three of the...
SCOPE
1.1 These instrumental test methods cover the determination of moisture, volatile matter, and ash, and the calculation of fixed carbon in the analysis of coal and coke samples prepared in accordance with Practice D2013 and Practice D346.
1.2 These instrumental test methods are not applicable to thermogravimetric analyzers using microgram size samples.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 7582 – 09
Standard Test Methods for
Proximate Analysis of Coal and Coke by Macro
Thermogravimetric Analysis
This standard is issued under the fixed designation D 7582; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 Theseinstrumentaltestmethodscoverthedetermination
of moisture, volatile matter, and ash, and the calculation of
3. Terminology
fixed carbon in the analysis of coal and coke samples prepared
3.1 For definitions of terms used in this test method, refer to
in accordance with Practice D2013 and Practice D346.
Terminology D121.
1.2 These instrumental test methods are not applicable to
thermogravimetric analyzers using microgram size samples.
4. Summary of Test Method
1.3 The values stated in SI units are to be regarded as
4.1 In thermogravimetric analysis the mass of a sample in a
standard. No other units of measurement are included in this
controlled atmosphere is recorded repeatedly as a function of
standard.
temperature or time, or both. In macro thermogravimetric
1.4 This standard does not purport to address all of the
analysis a sample size of approximately 1 g is used. All mass
safety concerns, if any, associated with its use. It is the
measurements are conducted by the system. In a typical
responsibility of the user of this standard to establish appro-
analysis, the temperature is normally ramped from ambient to
priate safety and health practices and determine the applica-
a specific temperature and held at that temperature for a
bility of regulatory limitations prior to use.
prescribed length of time. The mass change is recorded
repeatedly during the entire procedure. For the thermogravi-
2. Referenced Documents
2 metric analysis of coal and coke samples the moisture and ash
2.1 ASTM Standards:
analyses are complete when the sample reaches a constant
D121 Terminology of Coal and Coke
mass as defined in the instrumental operating parameters.
D346 Practice for Collection and Preparation of Coke
Alternatively, the measurement of moisture and ash can be
Samples for Laboratory Analysis
considered complete after heating the sample for a fixed period
D2013 Practice for Preparing Coal Samples for Analysis
oftime.Inthevolatilematteranalysis,thesamplesareweighed
D3173 Test Method for Moisture in theAnalysis Sample of
after heating to 950°C and held at this temperature for 7 min.
Coal and Coke
4.2 Moisture is determined by measuring the loss in mass of
D3174 Test Method forAsh in theAnalysis Sample of Coal
the analysis specimen of coal or coke when heated under
and Coke from Coal
specified conditions of temperature, time, atmosphere, speci-
D3175 Test Method for Volatile Matter in the Analysis
men mass, and equipment specifications.
Sample of Coal and Coke
4.3 Volatile matter is determined by measuring the loss in
D3176 Practice for Ultimate Analysis of Coal and Coke
mass of the analysis specimen of coal or coke when heated
D3180 Practice for Calculating Coal and Coke Analyses
under rigidly controlled conditions. The measured mass loss is
from As-Determined to Different Bases
used to calculate the volatile matter after correcting for the
D3302 Test Method for Total Moisture in Coal
moisture content.
D5016 Test Method for Total Sulfur in Coal and Coke
4.4 Ash is determined by measuring the mass of the residue
Combustion Residues Using a High-Temperature Tube
remaining after burning the coal or coke specimen under
Furnace Combustion Method with Infrared Absorption
specified conditions of specimen mass, temperature, time,
atmosphere, and equipment specifications.
This test method is under the jurisdiction of ASTM Committee D05 on Coal
4.5 In these test methods, moisture, volatile matter, and ash
and Coke and is the direct responsibility of Subcommittee D05.21 on Methods of
can be determined sequentially in a single instrumental proce-
Analysis.
dure. Another procedure allows the moisture and ash to be
Current edition approved Nov. 1, 2009. Published November 2009.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
determined sequentially. Moisture and ash can also be deter-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
mined in separate determinations. Ruggedness testing and past
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7582–09
experiences have shown the volatile matter values determined reserved for the blank or reference crucible. The furnace is
on samples without first determining the moisture (drying the constructed so the cavity is surrounded by a suitable refractory
sample) are always higher than those of the dried samples. and insulated so as to develop a uniform temperature in all
4.6 Where a relative bias between these test methods and parts of the cavity, but with a minimum free space.The furnace
other ASTM test methods for the proximate analysis of coal shall be capable of being heated rapidly (30-45°C/min from
andcokehasbeenshowntoexist(16.2),theinstrumentusedin ambient to 950°C. The temperature shall be monitored and
these test methods must be calibrated using specimens of maintained at values specified for each determination. The
known composition covering the range of parameters being system shall have an integrated balance capable of weighing
determined. the crucibles and test specimens repeatedly throughout the
analysis. All mass measurements are conducted and recorded
5. Significance and Use
by the system. The sensitivity of the balance shall be at least
5.1 Moisture, as determined by this instrumental test 0.1 mg. Provision shall be made to introduce gases specified
method, is used for calculating other analytical results to a dry for this standard and to remove products of drying, devolatil-
basis using procedures in Practice D3180. ization, and combustion. The macro TGA system shall have a
5.2 Moisture can be used in conjunction with the air-dry venting fan, tolerant of hot product gases, to efficiently remove
moisture loss determined by Test Method D3302 to determine the exhaust gases.
total moisture in coal. Total moisture is used for calculating
7.2 Crucibles—with covers of composition and dimensions
other analytical results to an as-received basis using Practice
specified for the instrument by the instrument manufacturer.
D3180.
The covers shall fit closely enough so that the carbon deposit
5.3 Ash yield is the residue remaining after heating the coal
from bituminous, subbituminous, and lignitic coals does not
and coke samples (see Note 1).
burn away from the underside of the cover during the deter-
mination of the volatile matter
NOTE 1—The ash obtained differs in composition and amount from the
mineral constituents present in the original coal. Combustion causes an
expulsion of all water, the loss of carbon dioxide from carbonates, the 8. Reagents and Materials
conversion of iron pyrite into iron oxides and sulfur oxides, and other
8.1 Drying Gas—Nitrogen (99.5% purity), Argon (99.5%
chemical reactions. Ash yield, as determined by this test method, can
purity) or air, dried to a moisture content of 1.9 mg/L or less
differ from the amount of ash produced in furnace operations or other
(dew point –10°C or less).
combustion systems because combustion conditions influence the chem-
istry and amount of ash. 8.2 Inert Gas—Nitrogen (99.5% purity) or Argon (99.5%
purity).
5.4 Ash yield is used, (1) as a parameter for evaluating
8.3 Oxidizing Gas—Oxygen (99.5% purity) or air.
sampling procedures and coal cleaning processes, (2) in the
8.4 Reference Materials—Coal or coke material(s) meeting
ultimate analysis calculation of oxygen by difference using
the requirements of 10.1, with a certificate of analysis speci-
Practice D3176, (3) in calculations including material balance,
fying the reference value and the uncertainty of the reference
reactivity and yields of products relevant to coal conversion
value. Reference material(s) can be employed to calibrate the
processes such as gasification and liquefaction, (4) in calcula-
instrument for the determination of volatile matter. It is
tions to estimate the loading on electrostatic precipitators and
preferable to employ reference materials(s) that include infor-
on the fly ash and bottom ash disposal systems as well as
mation on the certificate of analysis concerning method(s)
erosion rates on boiler systems.
employed to determine volatile matter of the reference mate-
5.5 Volatile matter yield, when determined as herein de-
rial.
scribed, may be used to (1) indicate coke yield on carboniza-
tion, (2) provide the basis for purchasing and selling, or (3)
9. Hazards
establish combustion characteristics.
5.6 Fixed carbon is a calculated value. It is the difference
9.1 The user shall insure acceptable documented safety
between 100 and the sum of the percent moisture, ash, and
procedures are in place for the handling of all reagents and test
volatile matter. All percents shall be on the same moisture
materials and for the operation of laboratory equipment speci-
reference base.
fied for these test methods.
5.7 Moisture, ash, and volatile matter are three of the
9.2 Venting Equipment—Install equipment in the vicinity of
principal parameters used for assessing the quality of coal.
the apparatus to vent combustion and volatile gases evolved
during the test procedures from the laboratory.
6. Interferences
6.1 Therearenoknowninterferencesforthesetestmethods.
10. Analysis Sample
10.1 The analysis sample shall be the material pulverized to
7. Apparatus
pass a 250-µm (No. 60) sieve in accordance with Practice
7.1 Macro Thermogravimetric Analyzer (Macro TGA)—A
D2013 or Practice D346.
computer controlled apparatus consisting of a furnace with a
cavity large enough to accept crucibles containing test speci-
11. Preparation of Apparatus
mens that meet the minimum mass requirements of the
procedure. The macro TGAsystem can accommodate multiple 11.1 Verify the instrument can meet all specifications in the
crucibles, allowing for continuous analysis with one crucible standard with respect to gas flows, heating rates, and balance
D7582–09
sensitivity prior to use. Condition the instrument after initial 13.2.3 For volatile matter determinations following the
setup, or repairs, by conducting a run through a complete cycle moisture analysis, place covers on the crucibles in the TGA
without samples. carousel (the crucibles are placed automatically in some
11.2 Conditionnewcruciblesandcoversforuseinthesetest systems and manually in others). Program the instrument to
reweigh the crucibles, with specimens inside, and covers in
methods by heating under the same conditions of the test and
cool before use. place before initiating the volatile matter part of the cycle.
11.3 The macro TGA system can be programmed to termi- 13.2.3.1 To provide an inert atmosphere, use nitrogen or
nate the measurement process when the test specimens and argonwithaflowrateof0.7to1.4furnacevolumechangesper
crucibles have reached a constant mass. Crucibles are weighed minute to sweep away the volatile components. Raise the
by the instrument at specified intervals. The analysis is furnacetemperatureataratesuchthatthetemperatureisraised
from 107°C to 950 6 10°C in a 26-30 min time period (See
complete when the sample reaches constant mass. Constant
mass is defined as a point where the mass change is < or = to Note 2). Program the instrument to hold at this temperature for
7 min. The TGA weighs the covered crucibles at regular
0.05% over a nine-minute period, either by using not less than
three successive weighings or a fixed nine-minute period of intervals while the temperature of the furnace is raised. The
weightsofthecruciblesandcoversattheendofthe7-minhold
successiveweighings.Thismasschangeof0.05%isequivalent
to 0.0005 g for a 1.0000 g sample. Alternately, the instrument period are used in the calculation of the volatile matter.
can be programmed to allow for moisture and ash determina-
NOTE 2—It is the nature of resistance furnaces to start heating slowly
tion by heating the test specimens for the time periods, heating
with a gradual increase in heating rate until the furnace heating element
rates and soak temperatures specified in Test Methods D3173
controllerreducesthepowertomoderatetheheatingrate.Asaresult,high
and D3174. The mass measured at the end of the time period
furnace ramp rates are seldom ever uniform over the temperature range
selected. Selecting a heating time (26-30 min) with a high heating ramp
is used for calculations.
rate accomplishes the desired result, to duplicate the conditions (Macro
TGA furnaces set at 30-45°C/min ramp rate) that were used by the
12. Calibration and Standardization
laboratories in the interlaboratory study. At the same time, it allows the
12.1 The instrument can be calibrated for the determination
Macro TGA furnaces to moderate the heating rate enough to avoid
of volatile matter employing reference materials. The calibra- overshooting the selected high temperature of 950°C.
tion must be performed at the same furnace ramp temperature
13.2.3.2 With strongly caking low-volatile and medium-
as that used for the analysis. Do not use coal reference
volatile bituminous coals, the coke button can burst as a result
materials(s) for coke volatile matter calibration. Do not use
of the rapid liberation of volatile matter within the button.This
coke reference material(s) for coal volatile matter calibration.
is designated as popping. Such popping can blow the lid off the
Use coal reference material(s) with a reference value and
crucible and cause mechanical loss of the coked material.
uncertainty based on measurements made employing D3175 to
When evidence of such popping is observed, reject the deter-
calibrate this test method for the purpose of determining coal
mination and repeat the test with smaller test specimen sizes
rank.
until popping is no longer evident. Also, some high swelling
coals can expand beyond the volume of the crucible such that
13. Procedure
they raise the crucible cover and stick to the underside of the
13.1 The determination of moisture, followed by volatile
cover. This material can be lost when the crucible cover is
matterfollowedbyashcanbecarriedoutinsequenceusingthe
removed. For swelling coals e
...
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