Liquids, hydrocarbon content coal-derived

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. 

Synthetic liquid fuels derived from coal and shale will differ in some characteristics from conventional fuels derived from petroleum. For example, liquid synfuels are expected to contain significantly higher levels of aromatic hydrocarbons, especially for coal-derived fuels, and higher levels of bound nitrogen. These differences can affect the combustion system accepting such fuels in important ways. In continuous combustors, i.e. gas turbines, the increased aromatics content of coal-derived fuels is expected to promote the formation of soot which, in turn, will increase radiation to the combustor liner, raise liner temperature, and possibly result in shortened service life. Deposit formation and the emission of smoke are other potential effects which are cause for concern. Higher nitrogen levels in synfuels are expected to show up as increased emissions of N0X (NO+NO2) An earlier paper presented results of an experimental study on the effect of aromatics and combustor... 

In the studies carried out to date, eight fuels have been tested which include six synfuels and two petroleum derived fuels. The synfuels tested included SRC-II middle and heavy distillate fuels, a blend of these fuels, and one SRC fuel blended with the process donor solvent. Composition data for the various fuels are presented in Table I, where it can be seen that the coal derived liquids have a higher C H ratio than either the diesel or residual petroleum oils, indicative of a higher aromatic hydrocarbon content. The shale-derived DFM on the other hand is a highly processed fuel and has a C H ratio similar to the petroleum diesel oil. Complete analyses of all the actual fuels tested were unfortunately not available at the time of writing, and, where necessary, typical analyses have been taken from previous studies. 

Low-ionization-potential mass spectroscopy is an effective technique for analyzing the hydrocarbon content of coal-derived liquids. Approx-... 

Fischer-Tropsch (FT) synthesis converts natural gas-, coal- and biomass-derived syngas into liquid hydrocarbon fuels which are totally free of sulfur- and nitrogen-containing compounds and have very low aromatic contents [1]. FT synthesis proceeds on cobalt metal sites, the overall niunber of cobalt metal sites on supported catalysts depends on both cobalt dispersion and reducibility. Decomposition of cobalt precursor is an important step in the catalyst preparation, which could significantly influence both cobalt dispersion and cobalt phase composition [2,3]. 

Condensable liquid products and tars will also be prodnced these materials are noted for their high aromatic character and high oxygen content (predominantly phenolic oxygen). By analogy with petroleum-derived products, coal products also contain satnrated (straight- and branched-chain) material, olefins, aromatics, and naphthenes (satnrated hydrocarbon ring systems) with special emphasis on the latter two structnral types. 

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