Coal hydrogen distribution

The distribution of products from the hydrogenation of vitrinite and inertinite separated from Australian Bayswater coal is shown in Fig. 3 and Fig. 4 respectively. Fig. 5 shows the distribution of products from the reduction of Soya-Koishi coal by CD + H20. The product distribution shows a similar tendency to that of Yubari coal shown in Fig. 2. Thus, it indicates that the Py-2, Py-1, A, 02 can be considered as intermediate products in a consecutive coal hydrogenation reaction scheme. 

Figure 2. Distribution of products from Yubari coal hydrogenation at 400°C...

Figure 8. Distribution of structural parameters of asphaltene from Shin-Yubari coal hydrogenation at 450°C (O), H2 100kg/cm2 ( ), H2 75 + CHh 25 ( ),...

Aromatic-Aliphatic Hydrogen Distributions in Coals of Different Rank. 

Very commonly, however, the sample of interest is not a pure compound, but is a complex mixture such as a coal liquid. As a result, a specific structure determination for each molecular type is not practical, although it is possible to determine an average chemical structure. Features which may be determined include the hydrogen distribution between saturate, benzylic, olefinic, and aromatic sites. The carbon distribution is usually split into saturate, heterosubstituted saturate, aromatic + olefinic, carboxyl, and carbonyl types. More details are possible, but depend greatly on the nature of the sample, and what information is desired. 

Figure 2. Relation between atomic ratio Htotal/Ctotal and aliphatic hydrogen distribution of coal.

It should be noted that prior to 1950, substantial quantities of hydrogen mixed with CO were produced from coal and distributed in cities as town gas. Some cities in the world still distribute a 50% by volume mixture of H2 with CO in city distribution systems. Currently, hydrogen is an industrial commodity, derived primarily from natural gas and the technology for handling it is familiar to industry. 

The Germans used the relative distribution of the constituents in the coal hydrogenation product as a measure of the conversion of coal to liquid products. They referred to the variation of the distribution of the coal liquefaction constituents as the degree of hydrogenation (Aufhydrierungsbe-dingungen). 

Figure 10. Hydrogen distribution in char from infrared analysis. The hydrogen in the char is normalized by the amount of hydrogen in the starting coal sample. Chars from 80-sec vacuum pyrolysis of PSOC 212...

Other CRAMPS studies on fossil fuels have included the effects of thermal and chemical treatment on CRAMPS spectra of tar sands, determination of the hydrogen distribution in coal maoerals, effects of water on CRAMPS spectra of coals, and a comparison of proton aiomatidties in coals and macerals determined by CRAMPS and C dipolar dephasing methods. 

A study of the hydrogen distribution in the pyridine and chloroform extracts from coal has indicated that ca. 50% of the aliphatic hydrogen was present on carbon atoms directly attached to aromatic rings. Indeed, the aromatic carbon atoms directly attached to aromatic rings has, in part, been reaffirmed by use of proton magnetic resonance to examine hydrogen distribution in coal. 

For any particular coal, the distribution of carbon, hydrogen, and oxygen in the coke is decreased as the temperature of the carbonization is increased. In addition, the yield of gases increases with the carbonization temperature while the yield of the solid (char, coke) product decreases. The yields of tar and low-molecular-weight liquids are to some extent variable but are greatly dependent on the process parameters, especially temperature (Table 13.1 and Figure 13.1), as well as the type of coal employed (Cannon et al., 1944 Davis, 1945 Poutsma, 1987 Ladner, 1988 Wanzl, 1988). 

For a coal, the distribution of carbon, hydrogen, and oxygen in the carbonaceous product is decreased as the temperature of the carbonization is increased. In addition, the yield of gases increases with the carbonization temperature, while the yield of the solid (char, coke) product decreases. 

Figure 3.21 Distribution of coal-hydrogenation products versus hydrogen consumption...

Only a limited number of coal-denved pitches were examined by H NMR because of their low solubility in solvents commonly used m conventional proton magnetic resonance. Table 12 reports the distribution of hydrogen for three of the pitches. Unlike coal-tar pitches, which typically have over 85% of the hydrogen bonded to aromatic carbon, the matenals listed in Table 12 are characterized by a high content of aliphatic hydrogen. 

In contrast to fossil energy resources such as oil, natural gas, and coal, which are unevenly distributed geographically, primary sources for hydrogen production are available virtually eveiywhere in the world. The choice of a primary source for hydrogen production can be made based on the best local resource. 

The modern natural-gas industry has its origins in the nineteenth centuiy as urban gas works that distributed synthesis gas (a mixture of carbon monoxide, hydrogen and carbon dioxide made by the incomplete combustion of coal, oil, or organic wastes in the presence of steam). Gas works illuminated London streets even before 1800, and subsequently... 

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