Low-temperature pyrolysis and co-pyrolysis of Göynük oil shale and terebinth berries (Turkey) in an autoclave

Abstract

Low-temperature pyrolysis of Turkish Göynük oil shale (GOS) and terebinth berries as individual objects and their dry and hydrous co-pyrolysis in a closed system, in an autoclave was studied. The effect of pyrolysis conditions (temperature and duration) on the yield of extracts (hexane and benzene), gas and organic residue was investigated. The composition of extracts was determined via thin layer chromatography. The yield of the extracts increased with the increase of pyrolysis temperature and duration, and its maximum attained 48.5% from the initial organic matter for GOS and 40% for berries. On the other hand, supercritical water also affected product yields and composition of extracts derived from both GOS and terebinth berries. The total yields of extracts from hydrous pyrolysis were 57.3% and 60.0% for GOS and berries, respectively. However, the extracts of hydrous pyrolysis contained more polar heterocompounds and less nonaromatic hydrocarbons than those of dry pyrolysis. Addition of berries to GOS lowered the co-pyrolysis temperature about 10 °C for reaching the maximum yield of the total extract. Dry co-pyrolysis of GOS with berries resulted in additive rather than in synergistic effect in the total extract yield, but the composition of the extract as a fuel - more nonaromatic hydrocarbons (33.8%) and less heterocompounds (43.0%) than that of extracts from individual feedstocks - was improved. Similarly, in the case of hydrous co-pyrolysis, the yields of extracts (hexane and benzene), gas and organic residue consisted of partial contributions of the yields from the initial feedstocks. © 2011 Estonian Academy Publishers.