Coal liquefaction residues

Walker, P. L. Spackman, W. Given, P. H. Davis, A. Jenkins, R. G. Painter, P. C. "Characterization of Mineral Matter in Coals and Coal Liquefaction Residues", Annual Rept. AF-832 from Pennsylvania State University to Electric Power Research Institute, 1978. 

In the development of coal liquefaction processes considerable effort has been concentrated on the coal liquefaction part of the process. In contrast, less effort has been directed toward utilization of the coal liquefaction residue or vacuum tower bottoms. 

Given, P.H., et. al., Characterization of Mineral Matter in Coals and Coal Liquefaction Residues, EPRI Annual Report AF-832, Research Project 3361, Pennsylvania State University, December, 1978. 

Robin, A.M., Hydrogen Production from Coal Liquefaction Residues, EPRI Final Report AF-233, Research Project 714-1, Texaco, Inc., December, 1976. 

The measure used to designate the pyrrhotites observed in coal liquefaction residues is com monly the atom percent iron. Pollack and Spitler (4) have described the adaptation of the well-established x-ray diffraction method of determining atom percent iron in natural pyrrhotites to coal liquefaction residues. The atom percent iron was estimated by this technique to 0.1 atom percent. The atom percent iron values observed in liquefaction residues, and in natural pyrrhotites, range from about 46 to 50. The latter would be the essentially stoichiometric FeS, troilite (high pyrrhotite). Experimentally, substances with all compositions from 43 to 50 atom percent iron have been prepared (2). The pyrrhotites found in nature manifest atom percent iron values clustered around 46.67 (Fe Sg ... 

L. Bai, Y. Nie, Y. Li et al., Protic ionic liquids extract asphaltenes from direct coal liquefaction residue at room temperature. Fuel Proc. Technol. 108 (2013) 94-100. 

CHARACTERIZATION OF COAL LIQUEFACTION RESIDUES BY THERMAL METHODS OF ANALYSIS... 

Table 2. Results of Elemental Analysis of Coal Liquefaction Residues.

In the above equation, C,H,S, and Ash represent the weight fractions of carbon, hydrogen, sulfur, and ash in the residues. When the values given in Table 2. are used with this equation, an "as received" calorific value of 12,365 BTU/lb (28.76 MJ/Kg) is obtained for the Process 1 residue and a value of 6,157 BTU/lb (14.32 MJ/Kg) is obtained for the Process 2 residue. To say the least, excellent agreement is observed for these two different methods of obtaining the calorific content of these coal liquefaction residues. Furthermore, one may observe from these values that the Process 1 residue shows excellent potential as a direct combustion fuel source. 

The use of thermal methods of analysis for the characterization of coal liquefaction residues can provide much information regarding the physical nature and composition of such coal conversion byproducts. Their thermal and oxidative stabilities are readily assigned from both TG and DSC methods. Heat history effects may be observed from both DSC and WA techniques. Volatile matter content, fixed carbon values, and ash content are readily obtained from thermogravimetry, Calorific values are accurately determined by dynamic DSC studies in flowing air atmospheres. Furthermore, volatilization profiles by TG and combustion profiles by both DSC and DTG may be used as tools for fingerprinting such residues. The use of computerized DSC offers the additional concept of normalized comparisons and subtraction of these profiles versus temperature. A combination of the information obtained from thermal methods of analysis, elemental analysis, microscopic and spectroscopic techniques, and solubility studies may lead to the total characterization of coal conversion by-products. 

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