Exinite

In Figure 9 the vitrinite + exinite content and the reactive maceral content, as determined by ISCOR, are plotted against the total conversion for the hot-rod technique. Figure 10 plots the same information for the autoclave results. 

The different slopes for the lines of best fit for total reactives and vitrinite + exinite reflects the special petrology of the majority of South African coals used in this study (see Table III). For these coals the reactives contain a high proportion of semi-fusinite in the inertinite. 

Figure 9. Percentage conversion against vitrinite + exinite (%) and total reactive macerals (X) (hot rod mode) ( 1)...

In addition to the Permian coals there are occurrences of Mesozoic and Tertiary coals in Australia. Mesozoic coals occur in small basins in South Australia, Tasmania, New South Wales and Queensland and vary in rank from brown to bituminous. Perhaps the most notable occurrences in the present context are the Walloon coals in the Clarence-Morton basin in Queensland, e.g. Millmerran bituminous coal (78% carbon, vitrinite plus exinite 90%). ... 

It is possible to produce some liquid hydrocarbons from most coals during conversion (pyrolysis and hydrogenation/ catalytic and via solvent refining)/ but the yield and hydrogen consumption required to achieve this yield can vary widely from coal to coal. The weight of data in the literature indicate that the liquid hydrocarbons are derived from the so-called reactive maceralS/ i.e. the vitrinites and exinites present (7 8 1 9). Thusf for coals of the same rank the yield of liquids during conversion would be expected to vary with the vitrinite plus exinite contents. This leads to the general question of effect of rank on the response of a vitrinite and on the yield of liquid products and/ in the context of Australian bituminous coals, where semi-fusinite is usually abundant/ of the role of this maceral in conversion. 

Figure 2. Noncatalytic hydrogenation—product yields vs. vitrinite + exinite content. Curve a, total conversion (X) Curve b, extract ( ) (10). (Note Lines a and b relate to coals where the mean maximum reflectance (R0 max) of the vitrinite fall in the range 0.43-0.68%. Values in parenthesis refer to R0 max for...

An implication of Cudmore s data (10) for the sub-bituminous and high volatile bituminous coals is that the semi-fusinite as such appears to contribute little to the conversion products, otherwise the apparent dependence of yield on the vitrinite (+ exinite) content would not be so linear. 

For example, Beynon and Cwm coals when digested in anthracene oil give extraction yields of 68% and 47% respectively. This variation can be explained by reference to the maceral composition of the coals. Beynon coal contains a lower concentration of inertinite than the Cwm coal (Table V). In experiments where relatively pure samples of petrographic species were digested in anthracene oil, exinite and vitrinite were shown to be highly soluble, whilst in comparison the inertinite was almost completely insoluble. Similar variations in reactivity of macerals have been reported from studies of solubility in pure organic solvents (1(3). 

CRC 502) are the most soluble. In comparison, the extraction yields of exinites were independent of coal rank. The subdivision of inertinites into fusinite and micrinite showed that fusinite was completely insoluble in anthracene oil, whilst the micrinite was slightly soluble. 

The coal studied, 78% C and 15.8% 0 daf, is derived from Carboniferous deposits from the Ziemowit mine in Poland. Its petrographic composition /% vol. dmmf/ is vitrinite, 60 exinite, 12 and inertinite, 28. 

Of the three major groups of petrographic constituents (termed macerals see appended note), vitrinites and exinites ... 

Figure 1. Petrography of Lower Kittanning coal at West Kittanning. Pennsylvania. Symbols V—vitrinite, E—exinite, M—micrinite, SF— semifusinite, F—fusinite...

Similar reflectances of some of the macerals (especially exinite and vitri-nite) in standard oil of n = 1.515 caused difficulties of positive identification. To circumvent this problem, an index oil adjusted to n = 1.60 was compounded from 1-bromonaphtnalene and cedarwood oil. The mixture provided sufficient differences in reflectivity between macerals for meaningful quantification. 

Layer No. Column V it finite Exinite MicHnite S emifusinite Fusinite... 

Bed Sample No. Vitrinite Exinite Micrinite fusinite Fusinite Ash inches... 

Column Vit finite Exinite Micrinite Semifusinite Fusinite... 

Figure B. Clarite with microspores in a high volatile bituminous coal (37% V. M.). Above untreated, below after a-irradiation. The reflectance of vitrinite and exinite increased to the degree of reflectance of a medium volatile coal (with 26% V. M.). Polished section, oil immersion, X 500 (from Brennstoff-Chemie 46, 13 (1965))...

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