Temperature-programmed co-pyrolysis of Soma-lignites form Turkey with polypropylene (PP) was investigated. The aim of this research was to determine the volatile product distribution and product evolution rate of co-processing of Soma-lignites with PP. A series co-pyrolysis operation was performed with lignites and PP using a 1:3, 1:1, 3:1 total carbon ratio of lignites to plastic. A fixed bed reactor was used to pyrolyse small sample of lignites and PP mixture 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 co-pyrolysis products were analyzed by capillary gas chromatography and the total product evolution rate was investigated as a function of temperature and time. n-Paraffins and 1-olefins in aliphatic fraction of co-pyrolysis products were classified by a carbon number. 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. The assessments were based on incorporating the results on temperature-programmed pyrolysis of lignites and PP. The effect of co-processing of lignites with PP was determined by calculating the difference between the experimental and the hypothetical mean value of conversion of total organic carbon into volatile products. Conversion into volatile hydrocarbons was found higher with increasing PP ratio in lignites-PP system while C16+ hydrocarbons and the amount of coke deposit were lower in the presence of PP. (C) 2002 Elsevier Science B.V. All rights reserved.