Classification of volatile products evolved from temperature-programmed pyrolysis of Soma-Lignite and Şırnak-Asphaltite from Turkey

Abstract

Temperature-programmed pyrolysis of Soma-Lignite and Şırnak-Asphaltite were investigated. The aim of this research was to determine the volatile product distribution and product evolution rate during pyrolysis of lignite and asphaltite as a function of temperature and time. A fixed-bed reactor was used to pyrolyze small sample of lignite and asphaltite under an inert gas flow (argon). A special sampling technique was used for collecting organic products released from the reactor at different temperature and time intervals. The pyrolysis products were analyzed by both capillary gas chromatography (GC) and GC–mass spectroscopy (GC–MS) coupling. The temperature at which product evolution rate is the highest proved to be ∼430 °C both for lignite and asphaltite in pyrolysis operation. n-Paraffins and 1-olefins in aliphatic fraction of pyrolysis products were classified by carbon number. The hydrocarbons produced by pyrolysis of lignite and asphaltite contained 32.4 and 30.1 wt.% of n-paraffins, respectively, at the maximum product release temperature. 1-Olefins produced by pyrolysis of lignite and asphaltite were determined and found as 10.2 and 16.6 wt.% of the pyrolytic oil, respectively. In addition, the performance of the experimental apparatus was investigated by establishing a carbon balance, and the degree of recovery of total organic carbon of the samples as aliphatic hydrocarbons and in solid residue was determined. Conversion into volatile hydrocarbons was found to be lower but the amount of carbon in solid residue was higher for lignite than for asphaltite pyrolysis.