Study On Pyrolysis And Catalytic Pyrolysis Of Fushun Oil Shale

Oil shale?OS?is an unconventional energy source.Its derived shale oil is similar to crude oil and has high hydrogen-carbon atomic ratio?H/C?,and their extensive reserves worldwide make OS an ideal substitute for crude oil.Pyrolysis has attracted widespread attention as the most effective way to utilize oil shale.In order to study the pyrolysis characteristics and pyrolysis products?shale oil?of Fushun OS,pyrolysis,catalytic pyrolysis and kinetics were studied.Various test analysis methods were used to study the basic characteristics of OS.The effects of heating rate and shale ash?SA?on the pyrolysis characteristics of OS were investigated by thermogravimetric analysis?TG?.In this paper,by changing the loading and type of transition metal salt?ZnCl₂,NiCl₂·6H₂O,and CuCl₂·2H₂O?on SA-based catalyst?SA-Q?,the effect of different types of transition metal salts on shale oil composition was analyzed.Based on the TG study,the kinetics of pyrolysis and catalytic pyrolysis of OS were studied.The main work is as follows.The basic characteristics of OS and SA are analyzed.It is found that OS is a layered solid sedimentary rock containing high ash?77.19 wt.%?and high H/C?2.09?.Its minerals are mainly kaolinite and illite.It is composed of silicate,quartz and a small amount of carbonate.The organic matter is mainly aliphatic.In addition,the shale ash?SA?pore size distribution is not uniform,mainly composed of SiO₂,Al₂O₃,and Fe₂O₃.The effects of heating rate and SA addition on the pyrolysis characteristics of OS were studied.The pyrolysis kinetics of OS was studied by DAEM model,Coats-Redfern model,FWO model and Doyle method.TG analysis showed that both the initial pyrolysis temperature and termination temperature of OS pyrolysis increased with increasing heating rate in 5 to20?/min.SA can promote the pyrolysis of OS,and the ratio of OS:SA optimal quality is 2:1.Coats-Redfern model analysis showed that the activation energy also increased with the increase of heating rate,which was109.4 kJ/mol when the heating rate was 20?/min.In addition,the activation energy was found to increase as the conversion rate increased by the DAEM model,the Doyle method,and the FWO model.The effect of SA-Q catalyst on OS pyrolysis was investigated.Coats-Redfern model was used to analyze the effect of catalyst on the activation energy of OS pyrolysis.Within 0.1 to 3 wt.%of transition metal salt,with the increase of transition metal salt load,SA-Q catalyst not only reduces the temperature at OS initial pyrolysis temperature and maximum weight loss rate,but also reduces the activation energy required for the reaction.The addition of SA-Q reduces shale oil and semi-coke?SC?yield,increasing gas and lost production.By comparing the transition metal salt loading of SA-Zn,SA-Ni and SA-Cu catalysts to 3 wt.%,SA-Cu not only has the highest ability to reduce the activation energy of OS pyrolysis?32.84kJ/mol?,but also increased the gas and loss yield during pyrolysis,which was4.4 wt.%higher than that of OS alone.Therefore,when SA is used as the carrier,the catalytic effect of the transition metal salt is CuCl₂·2H₂O>NiCl₂·6H₂O>ZnCl₂.The compositional analysis of shale oil indicates that the shale oil is mainly composed of aliphatic hydrocarbon materials.SA and SA-Q not only promote the decomposition of long-chain aliphatic hydrocarbons into short-chain aliphatic hydrocarbons,but also promote the formation of aromatic compounds in shale oils.In addition,SA-Q catalyst also increased the content of aliphatic compounds and oxygenates in shale oil.By comparing the stability of shale oil and the formation of aliphatics,the order of catalytic effect of loading transition metal salts on SA is CuCl₂·2H₂O>NiCl₂·6H₂O>ZnCl₂.