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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 1573-2001 Determination of Thermal Stability of Coal in whole.
In addition to a number of editorial changes, the following main technical changes have been made with respect to the GB/T 1573-2001:
— the terms and definitions are added (see Clause 3);
— the principle is modified (see Clause 4; Clause 3 of Edition 2001);
— the technical requirements for muffle furnaces are added (see 5.1);
— the clause of “Sample” is added, and the quality of prepared samples is modified (see Clause 6; 5.1 of Edition 2001);
— the heating time in the determination is clarified (see 7.2; 5.3 of Edition 2001);
— The clause of “Test Report” is added (see Clause 10);
This standard was proposed by the China National Coal Association.
This standard is under the jurisdiction of National Technical Committee 42 on Coal of Standardization Administration of China (SAC/TC 42).
The previous editions of this standard are as follows:
— GB/T 1573-1979, GB/T 1573-1989, GB/T 1573-2001.
Determination of Thermal Stability of Coal
This standard specifies the principle, apparatus, sample, procedures, expression of results, precision and test report for the determination of thermal stability of coal.
This standard is applicable to lignite, anthracite and non-cohesive bituminous coal.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 474 Preparation of Coal Sample
GB/T 483 General Rules for Analytical and Testing Methods of Coal
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 483 and the following apply.
3.1
thermal stability
a measure of the ability of coal to maintain a specified particle size when heated
The thermal stability index (TS+6) is taken as the mass fraction of residual coke mass of particle size larger than 6mm in the sum of residual coke mass of each particle size class after heating of coal sample with certain particle size under specified conditions. The mass fraction of the residual coke mass of 3mm to 6mm and less than 3mm in the sum of the residual coke mass of each particle size was taken as the auxiliary thermal stability index (TS3~6, TS-3).
Note: GB/T 483-2007, definition 3.3.22, modified.
4 Principle
The coal sample with a certain volume and of 6mm to 13mm particle size shall be measured and heated by air in muffle furnace at (850 ± 15)°C for 30min, then weighed and sieved to calculate the mass fraction (which is used as thermal stability index and auxiliary thermal stability index, respectively) of residual coke mass with particle size greater than 6mm, 3mm to 6mm and less than 3mm respectively in the sum of residual coke mass of each particle size level.
5 Apparatus
5.1 Muffle furnace
Equipped with constant temperature adjustment device and can be maintained at (850 ± 15)°C, constant temperature area shall not less than 100mm × 230mm, and the back wall of muffle furnace shall be provided with exhaust holes and thermocouple insertion holes. The constant temperature area of muffle furnace shall be determined at least once a year. Pyrometers (including thermocouples and millivolts) shall be calibrated at least once a year.
5.2 Sieve shaker
Reciprocating sieve shaker, with an amplitude of (40 ± 2)mm and a frequency of (240 ± 20)min-1.
5.3 Circular hole sieve
The aperture is 6mm and 3mm, the square sieve of size matches the sieve shaker, and equipped with sieve cover and chassis.
5.4 Industrial balance
The maximum weight is 1kg, to the nearest 0.01g.
5.5 Crucible, with lid
Porcelain crucible or corundum crucible, with a volume of 100cm3.
5.6 Crucible holder
It is made of metal material with temperature resistance above 900°C. According to the size of constant temperature area of muffle furnace, the crucible holder can be made to place 5 or 10 crucibles.
6 Sample
As specified in GB/T 474, about 2kg of air-dried coal sample with particle size of 6mm to 13mm shall be prepared. The coal sample with particle size less than 6mm shall be carefully sieved and divided into two parts after mixing evenly.
Foreword II
2 Normative References
3 Terms and Definitions
4 Principle
5 Apparatus
6 Sample
7 Procedure
8 Expression of Results
9 Precision
10 Test Report
