Pyrolysis kinetics and maturation of coals from the San Juan basin

Temperature-programmed pyrolysis was used to analyze 18 coals and coaly shales from the San Juan Basin of the southwestern U.S., giving temperatures of maximum evolution rate (T max ) and pyrolysis yields. T max values increased with maturity (as measured by vitrinite reflectance [%R m ]). The pyrolysis yields remained constant or increased slightly with increasing maturity until a value for %R m of approximately 1.0 was reached, after which the yields declined rapidly. Pyrolysis-gas chromatography and pyrolysis-FTIR showed that alkane and alkene yields followed similar trends. A subgroup of coals from the Fruitland seam of the San Juan Basin was also analyzed by micropyrolysis at several constant heating rates to determine laboratory pyrolysis kinetics