Study On Oil Shale Pyrolysis And The Kinetics Of Products Generation Process

During low-temperature pyrolysis of oil shale, shale oil could be obtained withhydrocarbon ratio similar to crude oil. Shale oil is also an important alternative topetroleum. Rational utilization of oil shale has a special strategic significance formaking up the lack of resources and easing the shortage of crude oil. Pyrolysis of oilshale and kinetics study on pyrolysis products is the promise of optimalthermochemical conversion, and it is also the foundation for the comprehensivedevelopment and utilization of oil shale.In this paper, experiment of oil shale isothermal pyrolysis was carried out inself-built fixed-bed bench. The effect of different temperature and pyrolysis time onthe oil shale pyrolysis process of products generation was investigated. And thenaccording to the results, the kinetic parameters of oil shale pyrolysis shale oil andwater were researched.Pyrolysis of Fushun oil shale has been studied in the temperature range460℃~540℃with nitrogen as a carrier gas. With increase in temperature, the shale oilyield increases and reaches a maximum at520℃. The oil yield was6.8wt%and116.6%with respect to the Fisher assay. And then, the oil yield decrease fortemperature higher than520℃. The yields of gas and water increase with increase intemperature. Aliphatic compounds in shale oil were mainly comsisted by long-chainalkanes and olefins. With the temperature rising, the content of aliphatic compoundincreased significantly, in which the content of C6~C13and C14~C20graduallyincreased, while the amount of C20+was significantly reduced. Compounds of shaleoil aromatic were mainly clumsy category, indene, naphthalene and phenanthrene.Along with the temperature rising, the content of aromatic compound increasedinwhich light aromatics content of C6~C10improved whereas content of C11~C14declined. Content of C15+increased after temperature rised higher than520℃. Shaleoil content of asphaltenes and resins decreased with temperature increasing.Carbonization yield of each component in the gas improved with temperatureincreasing and the yield ratio of olefins and paraffins with same carbon numberincreased. At different temperatures, shale oil yield increased rapidly at first thengradually later with the pyrolysis time prolonged, production was not increased after60min in the end. Increasing trends of shale oil four component content with time were similar to the total oil yield.The generation kinetic parameters of shale oil and pyrolysis water wwerecalculated by total package kinetic calculation. The calculation results of oil shaleformation reaction activation energy and pre-exponential factor A were21.102kJ mol-1and2.201s-1, respectively, which were in agreement well with experimental values.For hot water pyrolysis reaction, due to the mineraldecompositon reactions weremixed with pyrolytic water reaction when temperature was higher than500℃whichwould result in the activation energy greatly changing, so that the total package wasno longer applicable. The pyrolysis water generation was mainly by kerogendecomposition proceeds below500℃, the calculated activation energy was26.7141kJ mol-1and pre-exponential factor A was0.0688s-1by first order kinecticequation.