Dependence of Liquefaction Behavior on Coal Characteristics. Part VIII. A Chemical Study of the Asphaltenes from the Liquefaction of Coal. Concluding Remarks for This Series of Reports. Final Technical Report, March 1981-March 198

摘要

The chemistry of asphaltenes was studied in an attempt to determine the influence of coal characteristics on the composition of the liquefaction products. Forty coals were liquefied in tetralin and the coals and asphaltenes were studied using spectroscopic, oxidative degradative, and derivatization techniques. A suite of 26 high-sulfur coals was selected to provide a homogeneous set with which to evaluate the relationships between coals and asphaltenes using bivariate and multivariate statistical techniques. Other coals studied were from 5 different geologic provinces; these had low sulfur contents, and several exhibited notably high hydrogen contents. Nuclear magnetic resonance was used to obtain carbon and hydrogen distributions, and infrared analysis was used to attain additional information on functional groups. Oxidation with trifluoroperoxyacetic acid was used to study hydrogen-rich structures, and the reaction was modified to better preserve primary oxidation products such as citraconic, homophthalic, cyclohexene dicarboxylic, and long-chain alkanoic acids. The asphaltenes from the high-sulfur coals were structurally homogeneous, since the range of variability was quite narrow in terms of the structural and compositional parameters. The carbon and oxygen contents of the asphaltenes varied linearly with coal rank parameters. This was also evident in the low-sulfur coals that were studied. However, the structural parameters obtained from the spectroscopic analyses and oxidative degradation of asphaltenes could not be statistically related to coal properties or behavior. The principal coal properties which influenced the chemical composition of asphaltenes were related to coal rank and petrology; however, other geologic considerations such as weathering and an accelerated rate of coalification also affected asphaltene structure. 10 references, 26 figures, 36 tables. (ERA citation 10:022286)