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Description:
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The kinetics of San Miguel (Texas ) lignite pyrolysis was investigated in range of 650 to 800°C at atmospheric pressure . An experimental system which facilitated the monitoring of the actual sample temperature , collection of gas and tar , and measurement of sample weight loss as a function of time was used . It is found that , in the range investigated , lignite decomposition into gas , tar , and char can be described by three parallel first order reactions . Examination of experimental data indicated that , in the range investigated , the rate of pyrolysis is controlled by intraparticle heat transfer . A simplified kinetic -transport model was used to estimate the individual reaction rate constants and the activation energies . The amount and composition of the pyrolysis gas products were also analyzed . The gas produced consisted mainly of carbon dioxide , carbon monoxide , hydrogen , and some low hydrocarbons . The hydrocarbon products consisted mainly of methane , ethane , ethylene , and trace amounts of C+3 compounds . |