Classification by rank

Analysis. Analyses of a number of lignitic coals are given in Table 3. Figure 1, a distribution plot of 300 U.S. coals according to ASTM classification by rank, indicates the broad range of fixed carbon values (18). According to the ASTM classification, fixed carbon for both lignite and subbituminous coals has an upper limit of 69%, but in practice this value rarely exceeds 61%. 

ASTM classification by rank Coke, wt % Tar, gal/ton Light oil, galAon Gas, ftVton Water, wt %... 

Lignitic coal, classification by rank, 6 711t Lignocellulose, 5 367-368 10 295 Lignocellulose-based raw materials,... 

Subbing formulations, gelatin in, 12 444 Subbituminous coal, 6 703 classification by rank, 6 1 lit defined, 6 829... 

ASTM Classification by Rank. Coals are classified in order to identify their end use and also to provide data useful in specifying and selecting burning and handling equipment and in the design and arrangement of heat-transfer surfaces. 

FIGURE 6.13 Distribution plot for over 300 coals of the United States, illustrating ASTM classification by rank as defined in Table 6.4. 

Fine grinding of coal is necessary to assure complete combustion of the carbon for maximum efficiency. The required pulverized fuel fineness is expressed as the percentage of the product passing through various sizes of sieves. Coal classification by rank and end use of product determine the fineness to which coal should be ground (Table 6.15). 

Table 2. Classification of Coals by Rank, International Committee for Coal Petrology ...

In 1963 a classification of coals by rank (differing from the ECE scheme) was pubUshed by the International Committee for Coal Petrology (Table 2) (9). This includes a classification of brown coal that correlates a number of important properties including the percent reflectance of vitrinite in the coal. This is a simpler version of that used in German practice, which further subdivides soft brown coals into foHaceous and earthy. Most brown coals belong to the latter group. 

Adapted, with permission, from D388-99, Standard Classification of Coals by Rank copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. 

ASTM 2003a. ASTM D388-99el Standard Classification of Coals by Rank. ASTM International. World Wide Web Address http// www.astm.org. 

Such data are necessary for calculation of parameters in the classification of coal by rank dry, mineral-matter-free volatile matter (or fixed carbon) as well as moist, mineral-matter-free gross calorific value. For volatile matter and fixed-carbon data, it is also necessary to assume that 50% by weight of the sulfur is volatilized in the volatile matter test and therefore should not be included as part of the organic volatile matter (nor should the loss from clays and carbonate minerals) ... 

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