Significance and Use
5.1 Moisture, as determined by this instrumental test method, is used for calculating other analytical results to a dry basis using procedures in Practice D3180.
5.2 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.
5.3 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.
5.4 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.
5.5 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.
5.6 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.
5.7 Moisture, ash, and volatile matter are three of the principal parameters used for assessing the quality of coal.
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 Test Methods D3173, D3174, and D3175 shall be considered the referee test methods.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
