Rapid Heating Pyrolysis of Coals and Vacuum Residues

Abstract

Rapid heating rate (-100°C/sec) pyrolysis studies of three different coals and two vacuum residues were carried out. Yields of total hydrocarbon gases (C1-C4) from coals increased gradually above temperature 450°C and amounted to about 5-8wt% above 850°C. Methane was the main component of the hydrocarbon gases formed and amounted to 70% of total hydrocarbon gases. Remarkable increases in the yield of hydrocarbon gases were observed in both temperature ranges of 500-550°C and 700-800°C. This corresponded to the increase in methane, ethylene, and propylene in these temperature ranges. Hydrogen, carbon monoxide, and carbon diox-ide were also observed above 500°C and these amounts increased with increasing pyro-lysis temperature. In the pyrolysis of vacuum residues of crudes, yields of C1-C4 hydrocarbon gases increased with increasing pyrolysis temperature, and ethylene was the main product. Among the two residues, a yield of C1-C4 hydrocarbon gases from Taching vacuum residue was higher, reflecting that Taching vacuum residue contains longer paraffinic straight chains than Iranian heavy's.