Tongchuan Oil Shale Pyrolysis Behavior Research

Oil shale is a kind of high ash content of sedimentary rocks which contain flammable organic matter. Oil shale can be converted into shale oil by retorting, which is similar to natural oil. Oil shale belong to unconventional resources, which also used to chemical industry, power generation, building industry, agriculture, etc. This article comprehensively study the composition and distribution regularities of gases and liquid that pyrolysis from Tongchuan oil shale.The effect of final temperature and persistent time on oil shale retorting were studied by Gray-King Assay analysis. The oil contents of Tongchuan oil shale are7.81%. In order to gain shale oil, the appropriate conditions is540℃final temperature and20min persistence.The effect of heating rate, particle size, mineral materials and hydrogen atmosphere on oil shale pyrolysis and gas products generation were investigated by TG-FTIR coupled technique. The starting temperature, ending temperature and maximum decomposition rate increased with the increasing of heating rate, and the temperature range of volatile component output became wider; The total weight loss of oil shale did not have certain regularity with the change of heating rate. The weight loss and weight loss rate of Tongchuan oil shale were the maximal at moderate particle size (61～98μm). Compared with demineralized oil shale, the weight loss and weight loss rate of raw oil shale relatively inreased25.5%,18.9%, respectively. The pyrolysis weight loss and maximal weight loss rate relatively increased6.07%,11.5%, respectively at hydrogen atmosphere, the temperature of the maximum decomposition rate brought forward2℃. From FTIR spectra, we can see the output of aromatic hydrocarbon, CnHm, CH4, CO and CO2increased with the increasing of heating rate. The output of main volatile component at particle size of61～98μm were obviously more than the others. The output of aromatic hydrocarbon, CnHm, CH4, CO and CO2decreased after demineralization compared with raw oil shale. The output of aromatic hydrocarbon, CnHm, CH4and CO increased at hydrogen atmosphere, however CO2decreased obviously.Analyse constitute and content of shale oil from Gray-King Assay with GC/MS, Tongchuan shale oil contained aliphatics, lightweight aromatics, polycyclic aromatic compounds, phenols, and heterocyclic compounds.Compared with500℃, aliphatics, polycyclic aromatic compounds and heterocyclic compounds increased lightly at550℃, lightweight aromatics and phenols decreased. Aliphatics, polycyclic aromatic compounds and phenols increased, lightweight aromatics and heterocyclic compounds decreased.Kinetic parameters of Tongchuan oil shale in pyrolysis and its activation energy regularities were obtained by Coats-Redfern. The pyrolysis of Tongchuan oil shale were described by three-step first order reaction,the second step were severe weight loss,at which the activation energy were maximal, the activation energy were smaller at first and third steps.