Carbon coal products, comparison

Possible inter relationships of natural substances are important. Similarities of the low molecular weight alkane isomers from crude oil and Fischer-Tropsch synthesis product have been reported. A similar composition for high temperature coal carbonization has been found. The C4 to C7 alkane isomers from these sources can be calculated quantitatively with equations developed for Fischer-Tropsch products. A reversal of the concentrations of the monomethyl isomers from CG (2 Me > 3 Me) to C7 (3 Me > 2 Me) occurs in all three products comparisons at higher carbon numbers indicate some dissimilarities. Naphthene isomers for crude oil and high temperature coal carbonization also have similar compositions. Aliphatic hydrocarbons from low temperature coal processes are considerably different. The C1 isotopic composition of pure compounds from the various sources are being compared in order to provide information on their origin. 

Coal Derivatives. In attempting to extend this investigation to coal products, it was evident that not many isomeric analyses have been carried out. In the case of low temperature tar the predominant species reported have been normal olefins and normal alkanes. Branched alkane isomers are probably very low in concentration. However, limited data for high temperature coal tar (10) and for coal hydrogenation products (7, 12) indicate a close comparison of C7 alkanes with those from crude oil and the values predicted by the Fischer-Tropsch equation (Table III, top). A close comparison is notable also in the bottom part of Table III, which gives data for the Co and C7 naphthenes from high temperature coal carbonization, coal hydrogenation, and a crude oil. 

The major fossil fuels are coal and petroleum. Marine organisms were typically deposited in mud and under water, where anaerobic decay occurred. The major decomposition products are hydrocarbons, carbon dioxide, water, and ammonium. These deposits form much of the basis for our petroleum resources. Many of these deposits are situated so that the evaporation of the more volatile products such as water and ammonia occurred, giving petroleum resources with little nitrogen- or oxygen-containing products. By comparison, coal is formed from plant material that has decayed to graphite carbon and methane. 

Preliminary measurements have been made on Phillip s n-hexane, known to be derived from natural gas, and comparisons have been made with the Fischer-Tropsch standard, n-hexane. Both products were purified by Dr. B. D. Blaustein of the Pittsburgh Coal Research Center by means of gas chromatography. It is known from the work of Stevenson that breakage of a carbon-12-carbon-12 bond is more probable than breakage of a carbon-12-carbon-13 bond. This means that if the n-hexane from natural gas were formed by a bond... 

Comparison of analyses of heptane insolubles from the liquefaction of Monterey bituminous and Wyodak subbituminous coals in the hydrogen-enriched solvent shows that carbon, hydrogen and oxygen concentrations converge with increasing reaction severity to form a product with similar elemental analyses. The same convergence is seen when the hydrogen-depleted solvent is used. 

Removal of asphaltenes and preasphaltenes was easier than heteroatoms. At an increase of a hydrogen-to-carbon atomic ratio by 0.16, they were 80% removed. A comparison can be made with Synthoil process product of hydrogen-to-carbon atomic ratio equal to 1.04 which was hydrotreated to hydrogen-to-carbon atomic ratio equal to 1.24. The asphaltenes and preasphaltenes were 77% and 99% removed, respectively (7). Squires (8) concluded that the preasphaltenes can be converted to asphaltenes and oils with very little consumption of hydrogen. Asphaltenes are the major consumers of hydrogen. Although Squires conclusions were based on donor-solvent coal liquefaction, similar results were reported... 

Viscosity is an important characteristic of pitches used as binders for the production of carbon and graphite electrodes. We used a Haake balance to measure SCT, petroleum and coal tar pitch viscosity, SCT pitches have viscosity between 1000-4000 cps at 160°C, A comparison of the viscosity-temperature relationship of two SCT pitches prepared by thermal and catalytic processes, a commercial petroleum and a coal tar pitch used for the production of carbon anodes is given in Figure 2. 

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds... 

A comparison of different coconut shell-based carbons (CC-602 and PCB) showed similar absolute capacities but a better performance and better adsorption kinetics of PCB during life time of the coal [55]. However, variations in coconut shell-based coal are vmpredictable due to their production process. Other carbon types might be more predictable in the adsorption performance, but their adsorption characteristics are not good enough. Therefore new adsorption materials have to be developed [19]. 

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