Macerals property

Bodily, D.M. The Effect of Maceral Properties on the Comminution of Coal Final Report DOE/PC/707 6-12, University of Utah, Salt Lake City, Utah, 1987. 

A third step in information gathering is related to the thermal history of the coal. Because the maceral properties change with the maximum temperature experienced by the coal, either in a natural deposit or in a technical system, an independent reconstruction of the process temperature might be possible. 

ASTM Property Alpha-ceUulo se Alpha-ceUulo se Macerated Glass fiber... 

A number of subdivisions of the maceral groups have been developed and documented by the International Commission on Coal Petrology (14). Table 1 Usts the Stopes-Heeden classification of higher rank coals. Periodic revisions include descriptions of the macerals, submacerals, morphology, physical properties, and chemical characteristics. Theories on the mode of formation of the macerals and their significance in commercial appUcations are also included of Reference 14. 

Pieces of coal are mixtures of materials somewhat randomly distributed in differing amounts. The mineral matter can be readily distinguished from the organic, which is itself a mixture. Coal properties reflect the individual constituents and the relative proportions. By analogy to geologic formations, the macerals are the constituents that correspond to minerals that make up individual rocks. For coals, macerals, which tend to be consistent in their properties, represent particular classes of plant parts that have been transformed into coal (40). Most detailed chemical and physical studies of coal have been made on macerals or samples rich in a particular maceral, because maceral separation is time consuming. 

Thus a good correlation between conversion yield and one of these properties obviously implies a similar correlation with the other property. The correlations between the volatile matter yield and the reactive maceral content and between the H/C atomic ratio and the reactive maceral content are not statistically significant. 

Thermal destabilization of the molecular lattice of aromatlc-rlch macerals In bituminous coals at temperatures above 600 K Is associated with their characteristic thermoplasticity (10). The relationship between the extent of this fusion and the molecular properties of the vltrlnlte and Inertlnlte macerals, however. Is not well understood. 

The low-volatile bituminous Bulli coal which contains no liptinite and has significant thermoplastic properties has a M2J pyrogram (Figure 2 (F)) showing only one fusion transition which is lesser in extent and shifted to higher temperatures than that of the Liddell coal. This transition is, of course, attributed to aromatic-rich macerals. 

What is the source for preparation of the molecule of interest Which kind of tissue maceration is optimal with respect to conservation of properties and yield ... 

Table I. Properties of Macerals from British Seams...

Coal reflectance (ASTM D-2798) is very useful because it indicates several important properties of coal, including determination of the maceral composition of coal, which, in turn, is helpful for the prediction of behavior in processing (Davis, 1978 Davis et al., 1991). Coal reflectance is determined by the relative degree to which a beam of polarized light is reflected from a polished coal surface that has been prepared according to a standard procedure (ASTM D-2797). Samples prepared by this practice are used for microscopical determination of the reflectance of the organic components in a polished specimen of coal (ASTM D-2798) as well as the volume percent of physical components of coal (ASTM D-2799). 

C OAL is AN extremely complex, heterogeneous material that is difficult to characterize. It is a rock formed by geological processes and composed of a number of distinct organic substances called macerals and of lesser amounts of inorganic entities called minerals. Each coal maceral and mineral has a unique set of physical and chemical properties that contributes to the overall behavior of coal. Although much is known about the mineral properties of coal, surprisingly little is known about the properties of the individual macerals. 

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