Vitrinite calculated

Figure 2. Solubilities and molecular weights of a vitrinite (80.8% C, daf) after nonreductive ethylation (yields calculated on ethylated product (daf))...

Separating the three macerals from the dull coal was difficult. The petro-graphical purity of the exinite is 86% and that of the micrinite 94%. For both macerals, vitrinite is the main impurity. Since the vitrinite has a petrographi-cal purity of 99%, it is not difficult to calculate the values for the pure exinite and pure micrinite from the experimental data on the highly enriched maceral fractions. All values reported in the tables are corrected ones. Table I summarizes the results of elementary analysis (maf) and the percentage of volatile matter. 

Table X shows, in columns 2 and 5, the numbers of CH and CH2 groups per structural unit which can be calculated from the results of Table IV. The values in columns 3 and 4 originate from Table VIII. The data from columns 2 and 5 lead to the values in columns 6 and 7, which give finally the H iicyci/ C iicyci values in columns 8 and 9 of Table X. As expected the micrinite possesses only one value for Haiicyci/Caiicyci (see Table IX). In the case of the exinite, as long as the true number of alicyclic carbon atoms per 10 structural units is not greater than 10-11, all C i icyci atoms can be once substituted, and therefore Haiicyci/Caiicyci can be 1. As soon as the true value of Caiicyci exceeds the value 11, CH2 groups have to be used to complete Caiicyci and therefore Haiicyci/C iicyci increases (this value lies in the extreme case of 57-58 C iicyci atoms per 10 structural units at 1.74). Since the maximum possible number of alicyclic carbon atoms is smaller for exinite than the number of CH2 groups present, all alicyclic C atoms can be unsubstituted, and therefore H iicyci/ Caiicyci can reach the value 2. The situation is somewhat different for the vitrinite. As long as the true number of alicyclic carbon atoms is not greater than 9-10 per 10 structural units, all Caiicyci atoms can be once substituted, and therefore the value 1 for Haiieyei/Caiicyci is possible. If only up to 25-26 alicyclic C atoms are present, all of them can be unsubstituted, and the value...

R(min) — Rar(max) — 0.8. If it is taken into account that only CH2 and CH groups can form alicyclic rings and that these rings contain not more than four and not less than two C atoms, limits for Cun eye 1 (alicyclic C atoms per unit) can be calculated. Results are exinite R[Pg.342]

V10-VI6. reflectance types VP Pitted, mylonitized vitrinite. b Mineral matter calculated according to Parr s formula (2). 

The stability factors were recalculated, and the pitted or mylonitized vitrinite was treated as semifusinite with two-thirds of it being assigned to inerts. Figure 6 shows the relation of the predicted stabilities to the stabilities actually obtained on the coke. Two sets of points are shown, one indicating the position of the stabilities as first calculated and the other the stabilities after re-evaluating the vitrinite. The second calculation is a considerable improvement in the relation of predicted to actual stabilities. The complete data upon which these calculations were made are shown in Table V, while other data pertinent to the evaluation of the samples coked in the movable-wall oven are given in Table VI. The position of the coal represented by point 5 was not improved by recalculation. This coal gave an actual stability of 20.2. 

Figure 7. Influence of rank (as measured by vitrinite reflectance) and type (as measured by percentage of reactive macerals) on metallurgical coke strength. Contour lines of equal coke strength (tumbler stability) were calculated by the author according to the procedures pioneered in the U.S. by Schapiro...

Figure 15. Arsenic concentrations in coals of the Black Warrior basin, Alabama. Shaded areas show the extent of coalfields of Alabama. The proportionally sized symbols. show the content of arsenic in coal samples analyzed by the USGS. Some symbols that plot inside each other are from the same core or coal face. The break points for the symbol groups were calculated using the natural breaks algorithm in the computer program Arcview . Dashed lines are contours of vitrinite reflectance data from coals. We are presently evaluating whether the tack of correspondence of high arsenic content with high vitrinite reflectance values is an artifact due to low sample density or reflects an actual trend in the data.

Fig. 7. Cross plots of calculated vitrinite reflectance equivalent biomarker maturity (Ro Ts) and light hydrocarbon maturity (Schaefer Ro) effectively indicates that almost all oils are mixtures in the true sense with a range of maturities of charge being present together in the trap. Only the flagged oils (red dots) may represent single maturity point charges, but even here that is doubtful. A mass fraction maturity concept better describes the maturity of an oil.

Temperatures within the sedimentary section calculated as a fimction of time are used to estimate the maturation level of the organic matter. The kinetic model of vitrinite maturation (Sweeney and Burnham 1990) is the primary method of maturity estimation. Comparison of measured vitrinite reflectance Rg) with the calculated values and present-day temperature profile (Fig. 6.6) is used to control modeling parameters. The time-temperature index (TTI) (Lopatin 1971 Waples 1980) is also computed as a simple method to describe the paleothermal regime. 

The thermal and burial histories of the basin for a variant that is free from erosion in the Permian were simulated for comparison with the main model (Fig. 6.7). This variant was controlled by present-day temperatures and vitrinite reflectance (similar to Fig. 6.6) and, by coincidence of the tectonic curve, calculated by removing the sediment and water load, resulting from variation in the thermal state of the basement (as... 

Table VII, Raymond et al. ( ) analyzed up to 400 vitrinite grains for organic sulfur content both with and without the aid of photomosaics. Using a t-statistic approach they calculated the number of analyses (n) for each run necessary to give a desired maximum variability of lOJt, at the 95% confidence level, from the true mean as defined by 100 analyses. As can be seen in Table VII, in no case was it necessary to analyze more than 14 vitrinite areas. The second advantage to analyzing only vitrinite is that Raymond et al. ( .) were able to achieve essentially identical results both with and without the use of photomosaics. Using texture and morphology to identify areas of vitrinite after the sample had been placed in the EPM was as successful as identifying the vitrinite using oil-immersion microscopy prior to analysis. It should be noted that only two of the four...

Individual macerals have also been studied by C magnetic resonance spectroscopy the macer-als were from a West Virginia bituminous coal (85.8% C). The calculated values were vitrinite 85%, exinite 66%, micrinite 85%, and fusinite 93%-96%. These results were in agreement with earlier work which had indicated that the aromaticity increases in the order ... 

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