Maceral behavior

The behavior of macrinite and micrinite in industrial processes is not clearly understood. As stated above, many U.S. petro-graphers treat both of these constituents as MinertM coal constituents. On the other hand, overseas workers have observed that micrinite may not be inert during carbonization. Because some micrinite appears to have been generated during the progressive coalification of the liptinite macerals, it might, instead, be quite reactive. 

The studies carried out consist of the megascopic description of the master columns study of thin sections for maceral assessment, determination of maceral composition on polished blocks in reflected light, determination of mean maximum reflectance values on polished pellets, proximate analyses of selected petrographic zones, hot stage studies on vitrinoids to determine the thermal behavior at various temperatures, electron microprobe and spectrochemical studies of selected zones to determine the nature of ash forming elements, analyses of certain zones petrographically important to determine the variation of total carbon, and hydrogen and microhardness determinations on certain macerals. 

Aliphatic structures are still of major importance in the second group of resinites, those of the bituminous coals, but aromatic structures are present in significant amounts. The spectra of these resinites display the type of absorption pattern that has come to be associated with other coal macerals, particularly the sporinites and to a large extent the vitrinites. This pattern is established in the resinites of the high volatile bituminous coals. Furthermore, resinites of this group are reactive during carbonization and oxidation processes in which their behavior parallels that of similarly affected vitrinites of equivalent rank. 

Peter H. Given What was the petrographic purity of your vitrains Have you any information about the behavior of other macerals than vitrinite ... 

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. 

There have been a large number of electron spin resonance (ESR) studies of coal and coal products,(1J but a microscopic interpretation of the resulting data has been hampered by the chemical heterogeneity of the coal samples examined. While several surveys of specially selected macerals have appeared, 3), the recent evolution of maceral separation techniques - now allows detailed ESR observations to be made on coals systematically fractionated in which coal rank, maceral type, and maceral density are simultaneously distinguished. The present report surveys the behavior of a variety of ESR properties of carbon radicals in exinite, vitrinite, and inertinite macerals in a variety of coals of different rank. These data... 

The ability to examine individual coal macerals provides an opportunity for a detailed study of the roles of the chemistry of the starting organic material and the effect of coalification on the final materials. The different macerals exhibit distinct g-value, linewidth and radical density signatures which are related to their chemistry. The present overview will be extended to a qualitative analysis of the ESR properties and the behavior of these macerals under reaction conditions. 

The difference in the extent of exchange at the benzylic and aliphatic positions of Tetralin is measurably less when the iner-tinites rather than the vitrinites from PSOC-106 and PSOC-828, are used to promote the reaction. Indeed, the inertinite obtained from PSOC-828 enhances the exchange reactions at the ben-zylic and aliphatic positions of Tetralin to a comparable degree. This decrease in selectivity suggests that the radicals formed in the initial fragmentation reactions of these semifusinite-rich macerals differ significantly in their behavior from the radicals produced from the other macerals. 

The differences in the reactivities of the macerals become more apparent in the 30-60 minute reactions. The behavior of the macerals and the reference compounds are compared in Table VIII. 

The composition of any individual coal beneficiation feed particle ranges from a nearly uniform metamorphized plant component through an almost infinite mixture series with macerals-minerals to an opposite end member as a nearly uniform mineral component. The behavior of a beneficiation feed during processing is determined by... 

Apart from the selective promotion of specific cell behavior, the ideal wound dressing would also provide an environment which would be more conducive to heahng. In this respect, the healing wound performs better in a moist healing environment but not in a macerated heahng environment. As such, the dressing should have the physical ability to deal with the exudates produced by the wound but at the same time not allow the wound to dry out and the tissues to desiccate. 

An interesting feature of the IR data is the peak at 2868 cm which correlates with the aromatic component at 1600, although it is believed to represent a combination of methyl and methylene stretches. Painter et al. (8) also found this behavior in IR spectra of coal macerals. Our data strongly suggest a reinterpretation of this peak assignment. 

In general terms, the behavior of coal during combustion, carbonization, pyrolysis, gasification, and direct conversion to liquids depends on the type and amount of the macerals present (Fryer et al., 1975 Falcon, 1978 Stach et al., 1982 Bend et al., 1991 Derbyshire, 1991 Kalkreuth et al., 1991 Murchison, 1991 Gagarin and Krichko, 1992 Sen, 1992 Speight, 2005,... 

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