Impact of internals on oil shale pyrolysis in fixed bed reactor

Abstract

Pyrolysis of oil shale was studied in a fixed bed reactor with internals consisting of a number of heat transfer enhancing plates and a pyrolysis gas collection channel in the bed center. Same experiment was also conducted in the reactor without internals for comparison. The pyrolysis characteristics were verified in terms of the heating rate of oil shale, products yield, quality of produced shale oil and pyrolysis gas composition. The results showed that the internals significantly enhanced the heat transferring of the material in reactor, improving the heating rate of the material around twice compared with the reactor without internals. Correspondingly, for Yilan oil shale, the pyrolysis oil (shale oil) yield was as high as 11.1% (db) in the reactor with internals, which was much higher than the case without internals. With increasing the furnace temperature, the shale oil yield gradually increased in the internals-enhanced reactor, whereas it was obviously decreased without internals. At a furnace temperature of 1000℃, the shale oil yield for the former reactor was 2.3 times of that for the latter, and the generated pyrolysis water was also lower for the former. The composition of the pyrolysis gas was similar for both the reactors, being rich in H2 and CH4 accounted for about 70 vol% of the total gas generated. The calorific value of the gas varied from 4406 to 5400 kcal/Nm3.