Pyrolysis of Rundle oil shale in a continuous fluidized bed retort

Abstract

Experimental results for the pyrolysis of Rundle oil shale in a 5 kg h − 1 fluidized bed pilot plant are reported. Experiments have been conducted over a range of temperatures, 480–540 °C, particle residence time in the range 18–35 min and with two particle size fractions, 0.15–0.53 mm and 0.53–0.99 mm. Increasing the retorting temperature resulted in a large increase in the hydrocarbon gas yield due to thermal cracking reactions. Oil yields less than Fischer assay were observed, probably due to coking of oil on the burnt shale. Over the ranges covered, particle size and solids residence time did not affect oil yield, relative to Fischer Assay oil yield. G.c.-m.s. has been used to study the effect of process parameters on oil composition. The volatility and aromaticity of the fluid bed oil were higher than for Fischer assay oil, and oil volatility and aromaticity increased with retorting temperature as a result of an increase in thermal cracking reactions with temperature.