Degree of coalification

Solvent extraction using nonreactive Hquids, such as C - or C -alcohols, benzene, or benzene-alcohol mixtures, yields generally 5—20% wax or bitumen (15). The yield and composition of the product are determined primarily by the petrologic character of the coal, not its degree of coalification. Montan wax is extracted from suitable coals for a variety of purposes. 

Classification by rankserves as a measure of their degrees of coalification and of their heating values, as expressed in BTU/lb. 

Rank property of coal that is descriptive of degree of coalification (i.e., the stage of metamorphosis of the original vegetal material in the increasing sequence peat, lignite, subbituminous, bituminous, and anthracite) (ASTM D-388). Anthracite rank of coal such that on a dry, mineral-matter-free basis, the volatile matter content of the coal is greater than 2% but equal to or less... 

The objectives of this study were (1) to reveal trends between selected regions of the infrared spectrum and accepted indicators of coalification (2) to determine the nature and degree of interdependency among these data using statistical analyses and (3) to evaluate the usefulness of FTIR data in measuring degree of coalification. 

McCartney J. T. and Teichmuller M. (1972) Classification of coals according to degree of coalification by reflectance of the vitrinite component. Fuel 51, 64—68. 

Peat is formed from degradative remains of plant material, mainly of the peat mosses Sphagnum and Hypnum. Peat types are categorized by botanical composition and degree of coalification. In peat, the coalification process is only beginning, and lignin,... 

Ito, O. Seki, H. lino, M. Diffuse reflectance spectra in near-i.r. region of coals a new index for degrees of coalification and carbonization. Fuel 1988, 67, 573-578. 

This system of classification, in fact, indicates the degree of coalification as determined by these methods of proximate analysis with lignite being classed as low-rank coal the converse applies to anthracite. Thns, coal rank increases with the amount of fixed carbon but decreases with the amount of moistnre and volatile matter. It is, perhaps, easy to understand why coal rank is often (and incorrectly) eqnated to changes in the proportion of elemental carbon in coal (ultimate analysis Chapter 8). 

The design of a new generation of conversion processes will require a deeper understanding of coal s intrinsic properties and the ways in which it is chemically transformed under process conditions. Coal properties such as the chemical form of the organic material, the types and distribution of organics, the nature of the pore structure, and the mechanical properties must be determined for coals of different ranks (or degrees of coalification) in order to use each coal type most effectively. 

The energy content of coal is related to its rank (degree of coalification) (Table 6.1) which is influenced by the content of nonfuel components (e.g., minerals and moisture) (Chapters 7 through 9). Thus, a primary objective of coal cleaning is to maximize the recovery of the heat value of the coal, consistent with achieving standard specifications for ash, moistme, and sulfur contents. 

With the aid of C-NMR-spectroscopy, which enables a direct insight into the carbon skeleton, the proposed adamantane structure model of coal could be largely dismissed. Figure 3.9 shows the solid-state C-NMR-spectra of coals with varying degrees of coalification. The resonance intensities in the aliphatic region at around 40 to 50 ppm decline markedly as coalification increases anthracite is formed practically exclusively from sp -hybridized carbon, whereas the sub-bituminous coal still has a large proportion of aliphatics. 

Coal is the most abundant fossil fuel on Earth and will continue to be an important energy source over the next several hundred years. It is estimated that at present consumption rates coal can last from 216 years to over 500 years [26]. Coal is a complex mixture of organic compounds composed of carbon, hydrogen, oxygen, and smaller amounts of nitrogen and sulfur, as well as moisture and minerals. According to its degree of coalification, coal... 

If one receives a coal sample, being usually a mix of several size fractions, the first step of investigation may be to determine the rank or degree of coalification of the coal for clear classification. This is necessary, for example, to identify... 

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