Coal characteristics

W. Spackman, "What Is Coal ", Short Conrse on Coal Characteristics and Coal Conversion Processes, Peimsylvania State University, University Park, Pa., Oct. 1973, 48 pp. 

Three West Virginia coals were supplied by the West Virgmia Geological Survey (WVGS). The particular coals were chosen on the basis of rank, petrographic composition, and mineral matter content The coals were limited to the bituminous rank since these coals are the most amenable to the NMP solvent extraction process and are mdigenous to the Appalachian region. Some of the coal characteristics are listed in Table 2. 

Given, P. H., Cronaucr, D. C., Spackman, W., Lovell, H. L., Davis, A., and Biswas, B., Dependence of coal liquefaction behavior on coal characteristics 1. vitrinite-rich samples. Fuel, 1975, 54, 34 39. 

Experimental Studies of the Dependence of Liquefaction Behavior of U.S. Coals on Coal Characteristics... 

A statistical study of the conversion with tetralin of 68 coals (60) must now be regarded as superseded by a later, more comprehensive paper (61), but it did show very clearly that bivariate plots are of little value in interrelating liquefaction behavior with coal properties at least two or three coal properties must be taken into account in seeking to explain the variance of liquefaction behavior, and some of these properties are not related to the rank of the coal. The paper implies strongly that any interrelationships of coal characteristics must necessarily be multivariate. Hence in any study of coal a large sample and data base is essential if worthwhile generalizations are to be made. 

Thus our rather small set of samples from a few selected areas of the U.S.A. shows a dispersion of some aspects of liquefaction behavior that is evidently associated with differences in the geology and geochemistry of the sample. Still more would we expect many sets of complex interrelationships between coal characteristics to emerge had we had a sufficiently large world-wide sample base to work with. 

In absolute terms, the quantities of reactor solids found in various processes do vary considerably. The rate of accumulation is related to several factors, such as coal characteristics, recycle solvent quality and reactor design. However, it can be stated in general terms that liquefaction of low rank coals (sub-bituminous C and lignites) does result in higher rates of accumulation of solids than do similar operations with bituminous coals. For example, during normal operations of the SRC-I pilot plant at Wilsonville, Ala., it has been found that the amount of solids retained varies from about 0.2-0.5 wt.% (moisture-free) for bituminous coals to 1.0-1.9 wt.% (moisture free) for a subbituminous C coal (Wyodak) (72). Exxon also reports much larger accumulations for lignites and subbituminous coals than those found for bituminous coals (73). 

H. L. Coleman, M. Painter, P. C. "The Relation of Coal Characteristics to Liquefaction Behavior", Quart. Tech. Prog. Repts for period Jan.-June 1978 to U.S. Department of Energy under Contract No. EX-76-C-01-2494, Rept. Nos. FE-2494-7/8, 1978. 

Coal Characteristics and Their Effects in Liquefaction Process... 

Consideration of the latter results in relation to those of Cudmore (10), discussed above, emphasize the need for caution when generalising on the influence of coal characteristics on conversion. Indeed, it would appear that the absolute and relative... 

Also, many of the effects mentioned relate to the overall conversion. In coming to grips with the effects of coal characteristics, attention must be given to the quality as well as the quantity of liquid products obtained during conversion as well as to the rate at which the conversion occurs under various conditions. These aspects, which have not been considered in this presentation, call for careful experimentation where the emphasis is not on maximising conversion but on careful control of experimental conditions with termination of experiments at only partial conversion. 

Guyot, R.E., "Influence of Coal Characteristics on the Yields and Properties of Hydrogenation Products", Aust. Coal Industries Research Laboratories, Report PR 78-8, June 1978. 

Relationship Between Coal Characteristics and Its Reactivity on Hydroliquefaction... 

The analytical data for coal samples used by other researchers and their experimental results are shown in Tables 6 and 7. A rough comparison of the liquefaction conditions used in this study to explore the parameter representing coal characteristics is shown in Table 8. 

Victorian brown coals (Yallourn, Morwell) used here and their data on coal characteristics were offered by the Herman Research Laboratory of the State Electricity Commission of Victoria, to whom the authors wish to express their appreciation. In addition, they wish to thank Nissho-Iwai Co. Ltd. who kindly acted as intermediary with respect to Victorian brown coals studied. 

Figures 5-7 are the spectra exhibiting the thermally extracted mobile phase components over different temperature intervals. All five coals mentioned in Figures 5-7 show distinct mass spectra in the mobile phase compared to the spectra of the macromolecular structure (25) and contain alkylsubstituted naphthalenes in the mobile phase although their relative amounts are dependent on coal characteristics. In general, (the temperature where the maximum rate occurs) in Py-FIMS was in the range of 430-470 C for bituminous rank coals. Around T, the macromolecular structure of bituminous rank coals is decomposed to yield FI spectrum showing the dominant peaks of alkylsubstituted phenols. Detailed FI spectra of the macromolecular structure for the ANL-PCS coals mentioned in Figures 5-7 are illustrated elsewhere (25).

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