Researching Yilan Oil Shale Pyrolysis In Fixed Bed Reactor

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 as11.1wt.%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 of1000℃, the shale oil yield for the former reactor was2.3times 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 H2and CH4accounted for about70vol.%of the total gas generated. The calorific value of the gas varied from4406to5400kcal/Nm3.Preheating temperature and particle size of oil shale had effected on the yield of shale oil in a fixed bed with interals. Preheating temperature of150℃,200℃,250℃300℃,furnace temperature of800℃pyrolysis products distribution shows that although the preheating time is longer, but oil shale increased19.63%on average, and the water yield was reduced16.18%on average, the gas yield was reduced11.82%on average. Shale oil yield had little difference after different preheating temperature.0.5-2mm oil shale got the highest yield of shale oil in the fixed with internals, at900℃furnace temperature. Different particle size ranges of oil shale had resulted in different gaps between different size and haved affected pyrolysis time and gas product residence in high temperature reactor and had affected shale oil yield at the same furnace temperature.Heating rates of material layer, thickness of material layer, product residence time, oil shale char and shale ash affected the shale oil yield by GDL-B. The faster heating rate, the thinner thickness of materials layer and the shorter residence time of product increased shale oil yield. Mixing up the oil shale with oil shale char or shale ash,the higher ratio of oil shale char or shale ash the lower of shale oil yield. Metal oxide exposing on the surface of shale ash could more contact with shale oil and resulting in lower shale oil yield under the same proportion of oil shale char.