Chemical characteristics of tars produced in a novel low-severity, entrained-flow reactor

Abstract

The distribution of the light gases and chemical characteristics of the collected tars are dependent on the both the transient particle temperature and ambient gas temperature. A number of investigators have reported that a range of coal types follows the same phenomenological sequence, although the tar yields vary significantly with coal rank characteristics. Moreover, chemical structural characteristics of ''primary'' tars are reported ''similar'' to those present in the parent coal, that is, the tar ''monomers'' reflect the coal ''polymer''. ''Primary'' tars are those collected in conditions in which ''secondary'' reactions have been minimized. Tars collected in these conditions, particularly tars collected in separation systems without extensive phase separation, will appear to be more like the parent coal than the primary tars originally evolved and collected in the above reactor system or other systems that minimize secondary tar reactions. The phenomenological sequence of heavy hydrocarbon formation, tar evolution and gas phase reactions appear similar for a wide range of coals, but the relationship between the chemical structures of primary tars and parent coal varies widely with coal type.